KR950011226B1 - Luminescent material - Google Patents

Abstract

The wave-changeable photosensitizer composed of CaSrW2O8: Eu+3, Nd+3 is produced by (a) mixing a calcium cpd. [CaSrW2O8 as a matrix with an europium cpd. [EuCl3, EuF3, Eu(NO3)3, Eu2O3, Eu(CO3)3, Eu2(SO4)3 and a neodymium cpd. [NdCl3, NdF3, Nd(NO3)3, Nd2O3, Nd2(SO4)3 , (b) firing the mixture in the alumina crucible under the oxidation atmosphere at 700-900 deg.C. For 30-100 min., and crushing it to 10-20 micrometer size, (c) firing it in the high temp. vacuum furnace inserted with an argon gas at 1000-1200 deg.C. for 90-150 min., and crushing it to 1-5 micrometer size, and (d) firing it at 500-700 deg.C. for 50-100 min. The photosensitizer is used in the forgery prevention of bank bills and checks.

Description

Wave-sensitive photosensitive agent and its manufacturing method

The present invention is to provide a novel light-sensitive photosensitive agent, which is a light emitting material that can be used as an identification means for counterfeit or other special printed matter, such as banknotes or securities, in particular by mixing in ink for printing such banknotes or securities, color copying Providing a novel waveguide photosensitive agent and a method of manufacturing the same, in which the identification means may not be easily exposed by preventing counterfeiting by a forgery and hiding a detection means in a mechanical automatic processing device such as counting, winding sorting and hand winding classification. It is for.

Among the fields of general printing are ultraviolet curing ink and infrared curing ink which are used to speed up the drying speed of ink (Ink) in printing. UV Curing Ink is an ink that uses a photosensitive resin, photosensitive monomer, and photoinitiator as its main ingredient, and it dries instantly by irradiating UV rays. The infrared curing ink is an IR varnish ), A gel varnish, and a solvent based solvent (Vehicle), which refers to a kind of ink for speeding up the drying speed of the ink, which are completely different from the present invention. There should be no confusion.

Banks and checks at home and abroad are often used with ink containing UV-reactive fluorescent substances to prevent forgery. However, the ultraviolet fluorescence reactant is exposed to fluorescence by irradiating ultraviolet light (UV Lamp), and the general development of the industrial technology facilitates the acquisition of ultraviolet light, so that the addition of the ultraviolet fluorescence material can be detected relatively easily. Accordingly, the present invention provides a wave sensitive photosensitive agent which is excited by light in a wavelength range of 450 to 630 nm, which is a visible region, and emits light in a wavelength range of 900 to 1500 nm, which is an invisible region. Natural colors can be obtained only by special optical devices such as Mercury Lamp, He-Ne laser, Monochromator, Scanning controller, etc. It is to prevent counterfeiting by copiers and to prevent counterfeits of banknotes and securities by making it difficult for counterfeiters to detect whether the photosensitive agent is injected or not.

The general principle of luminescence of luminescent material is energy in the ground state, which is the minimum state of energy which is sequentially filled from the orbital where the electrons of the element are low. When it absorbs and becomes an excited state (ci: Excited State) and removes external energy, electrons fall from the excited state to the ground state, which emits energy and emits light.

On the other hand, the optical spectrum represented by the ions of rare earth elements is characterized by a sensitive peak, which is shaped like an absorption spectrum and associated with 4f electron transitions. The light emission wavelength is strongly dependent on the parent crystal, and in 4f transition, the light emission shows light emission having a narrow spectral width depending on the type of ion.

The present invention utilizes the characteristics of the light emission principle and the rare earth element so that the visible region of the neodymium (Neodimium: Nd) having a light emitting region of 90-1500nm and the light emitting region of 600-1500nm using the europium (Eu) as an activator Providing a variable photosensitive agent which is excited by light in the wavelength range of 450-630 nm to have an emission peak wave length in the infrared (IR) region 900-1500 nm which is an invisible region. It is for.

The present invention uses _a known C _a S _r W ₂ O ₈ , which is a calcium compound, as a matrix, and the europium compounds [EuCl ₃ , EuF ₃ , Eu (NO ₃ ) ₃ so that the europium ions are 0.5-2.0% of the total. , Eu ₂ O ₃ , Eu (C ₂ O ₄ ) ₃ , Eu (CO ₃ ) ₃ , Eu ₂ (SO ₄ ) ₃ ] and neodymium compounds so that neodymium (Nd) ions are 0.3-1.0% of the total [NdCl ₃ , NdF ₃ , (CH ₃ CO ₂ ) Nd, Nd (NO ₃ ) ₃ , Nd ₂ O ₃ , Nd ₂ (SO ₄ ) ₃ ] are mixed and uniformly mixed, and oxidative for the first step reaction It was sintered at 700-900 ° C. for 30-100 minutes in an atmosphere and pulverized to about 10-20 μm, and it was found that neodymium ionization and crystallization of the matrix were incomplete by the first stage reaction alone. Thus, the present invention is introduced into the high-temperature vacuum furnace for the second step of the reaction mixture and then vacuumed to 10 ^-2 ~ ^-5 Torr, charged with argon gas and calcined at 1000-1200 ℃ for 90-150 minutes and neodymium The matrix was crystallized and pulverized to about 1-5㎛, and thus the crushed particles are stressed (Stress) state, there is a risk that the crystals change over time. Thus, in the third step for stabilization, the second step reactant was calcined at 500-700 ° C. for 50-100 minutes to obtain a variable photosensitive agent having a molecular formula of C _a S _r W ₂ O ₈ : Eu ⁺³ , Nd ⁺³ . It was. The present invention will be described in detail by way of examples as follows.

EXAMPLE

1st process

0.175 mol of calcium chloride (Calcium Chloride: CaCl ₂ ) and 0.175 mol of strontium chloride (Stronitum Chloride: SrCl ₂ ) and sodium tungstate (Na ₂ WO ₄ ) are dissolved in H ₂ O to form an aqueous solution, and then a precipitate is formed. Prepare reactant A, a Matrix. The scheme is as follows.

CaCl ₂ + SrCl ₂ + 2Na ₂ WO ₄ + H ₂ O → CaSrW ₂ O ₈ + 4NaCl + H ₂ O (A)

2nd process

Europium chloride (Europium Chloride: EuCl ₃ ) and neodymium chloride (Neodymiun Chloride: NdCl ₃ ) are added to the matrix amount of reactant A in an amount of 0.009 mol and 0.005 mol, respectively, to form a reactant B. .

3rd process

The reactant B is charged into an alumina crucible, calcined at 800 ° C. for 60 minutes in an oxidizing atmosphere, and then pulverized to about 15 μm to obtain a reactant C.

4th process

The reactant C was introduced into a high-temperature vacuum furnace for an oxidation-free reaction, vacuumed to a vacuum degree of 10 ^-3 Torr, charged with argon gas, calcined at 1200 ° C. for 90 minutes, and then heated to an average particle diameter of about 3 μm. Trituration yields reactant D.

5th process

The reaction is terminated by calcining reactant D at 600 ° C. for 60 minutes.

The variable photosensitive agent of the present invention obtained by terminating the above-described step reaction is a metallic ink varnish (High Tack Varnish) based on Coumarone-Indene Resin (Metallic Ink Varnish). Incorporated as a vehicle as a vehicle, the ink was prepared, the manufacturing aptitude was examined, and the results of experiments on factors such as changes in optical properties were obtained.

Experiment 1

Input rate and luminous intensity

Inks with 10, 20, 30, and 40 Wt% charge rate were prepared using the variable photosensitive agent, and the intensity was measured by printing with printed materials having the same print pattern (Pattern). (Emission Intensity) could be obtained.

TABLE 1

Experiment 2

Ink thickness and luminous intensity

As a result of measuring the intensity of a printed material having a thickness of 10, 20, 30, 40, and 50㎛ ink film using the same dose of the photosensitive agent (20Wt%), the thickness of the ink film was proportional to that shown in Table 2 below. Luminous intensity could be obtained.

TABLE 2

Experiment 3

Review of the impact of colored pigments

In order to examine the effects of light interference of colored pigments in the production of printed materials, fix the photosensitive agent at 20% and input the color pigments (colorless, yellow, green, blue, red, black). The light emission intensity was measured at 8% and the ink film thickness of 15 μm.

1) Colorless system (Ca sieving pigment)

2) Yellow (Symuler Fast Yellow)

3) Green system (Symuler Fast Yellow {4} + Phthalocyanine Blue {1})

4) Blue system (Phthalocyanine Blue)

5) Red system (Symuler Fast Red)

6) Black (Carbon Black)

Experiment 4

Flat printing experiment

In order to manufacture a large amount of flat printed matter, flat ink properties were prepared using Tack (3 min, 32 ° C. and 50 m / min) 162, Flow (3 min, 20 ° C.) and 870 dyne / cm ² . As a result of conducting the flat printing experiment on the flatbed printing machine, the printability, chemical resistance, light resistance, general resistance such as light resistance, and special prints such as luminous effect were good, and the ink composition ratio was as follows.

Flat Green Ink Composition Wt%

Transmutant Photoresist 35.16

Ca-based extender pigment 14.39

Phthalocyanine Blue 0.57

Symuler Fast Yellow 0.57

Metallic Ink Varnish 35.98

# 3 Varnish 7.36

Solvent (T-26) 5.56

Desiccant (Cobalt Octoate) 0.41

100.00

Solvent T-26 is a petroleum solvent with a boiling point of 260 ° C.

Experiment 5

Typography

Apart from flat printing experiments, typographic printing experiments were conducted to make the printing area as small as possible and to increase the effect of the photosensitive agent. The ink color was tested by producing three kinds of colorless, blue and red colors using only the photosensitive agent itself. As a result, it has good effect as a special print such as ink manufacturing aptitude, printing aptitude, and luminescent effect. As follows.

Ink property

Ink composition ratio (Wt%)

When the variable photosensitive agent of the present invention, which is an infrared light emitting material, is printed on special printed materials such as banknotes or securities, the luminous state is not visible, and the counterfeit can check whether the counterfeit photosensitive agent of the present invention is inserted. As such, it is expected to maximize the automatic inspection function, which is a mechanical automatic processing function such as authenticity discrimination, hand classification, automatic counting and currency exchange, and prevent the color copying of securities due to the large amount of color copiers.

Claims (8)

A variable photosensitive agent having the molecular formula CaSrW ₂ O ₈ : Eu ⁺³ , Nd ⁺³ . A process for producing a photosensitive agent, characterized in that a calcium compound is used as a matrix and crystallized after mixing a europium (Eu) compound with a neodymium (Nd) compound as an activator. The method of claim 2, wherein the matrix calcium compound is CaSrW ₂ O ₈ . [4] The method of claim 3, wherein the europium compound is mixed so that the europium ion (Eu) is 0.5-20% of the total, and the neodymium compound is mixed so that the neodymium (Nd) ion is 0.3-1.0% of the total. Method for producing a photosensitive agent. The method for producing a photosensitive agent according to claim 2, 3 or 4, wherein the compounding method of the matrix and the activator is a firing method. The method according to claim 5, wherein the firing method comprises a first step of calcination at about 10-20 μm after calcination at 700-900 ° C. for 30-100 minutes in an oxidizing atmosphere, and 10 ^-2 to ^-5 Torr The second stage reaction and the second stage reactant at 500-700 ° C. and 50-100 at 500-700 ° C. It is a 3rd step reaction which bakes for minutes, The manufacturing method of the photosensitive photosensitive agent characterized by the above-mentioned. 7. The calcination temperature and time of the first stage reaction are 800 DEG C and 60 minutes, and the size of the pulverized particles is about 15 mu m, and the vacuum degree of the vacuum furnace in the second stage reaction is 10 ^-3 Torr. The firing temperature is 1200 ℃, the firing time is 90 minutes, the size of the pulverized particles is 3㎛, the firing temperature and time in the third step reaction is 600 ℃ and 60 minutes, the manufacturing method of the photosensitive agent. The method according to claim 5, wherein the firing method comprises a first step of calcination at about 10-20 µm after firing for 30-100 minutes at 700-900 ° C. in an oxidizing atmosphere, and 120 minutes at 1400 ° C. in a oxidizing atmosphere. Method for producing a photosensitive agent, characterized in that the second step reaction and the second step reaction to pulverization to about 1-5㎛ after firing at 500-700 ℃ 50-100 minutes for the third step reaction.