JP3876013B2 - Anti-counterfeit sheet - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an anti-counterfeit sheet that can be determined as authentic, and more specifically, is used as a base sheet for certificate sheets such as banknotes, securities, cash vouchers, checks, tickets, and cards such as ID cards and credit cards. The present invention relates to an anti-counterfeit sheet that can be easily found by using a simple method even if these sheets are counterfeited or altered by a color copying machine, a digital color printer, or the like.
[0002]
[Prior art]
In recent years, due to the rapid performance improvement of digital color printers and color copiers, the preparation range of color reproducibility, resolution, density copy density, etc. has been remarkably improved and expanded, making it difficult to identify alterations and counterfeits at a glance. It has become. Thus, as an example of measures for preventing such counterfeiting and alteration, a number of techniques related to anti-counterfeiting sheets in which confidential information is printed on a sheet surface with fluorescent ink have been proposed. According to this technique, the secret information printed with fluorescent ink is difficult to see with the naked eye under visible light, but the secret information is irradiated by irradiating the sheet with ultraviolet light (black light). It is possible to visually recognize the fluorescent light so that the authenticity of the sheet can be determined.
[0003]
[Problems to be solved by the invention]
However, according to such a conventional anti-counterfeit sheet using fluorescent ink, there is no authenticity determination method other than the confirmation of secret information by irradiating black light, in other words, an ultraviolet irradiation device is installed. The authenticity cannot be determined except for the place where it is located, and the authenticity cannot be determined if the device breaks down.
[0004]
Therefore, according to the present invention, based on the conventional anti-counterfeiting method using black light, secret information cannot be visually recognized under visible light, but authenticity can be determined by making the secret information fluorescent with black light. In addition, another object of the present invention is to provide an anti-counterfeit sheet that can determine authenticity by a simple method without using an ultraviolet irradiation device.
[0005]
[Means for Solving the Problems]
As a result of intensive research in view of such problems, the present inventor has found that a conventional capsular wall material in a microcapsule of leuco dye crystal violet lactone (hereinafter abbreviated as CVL) known in the field of pressure-sensitive copying paper. The composition ratio between the core material and the thickness of the wall material is not particularly changed, and the CVL concentration in the organic solvent of the capsule core material is a concentration (about 2% by weight) that is applied to conventional pressure-sensitive copying paper. ) And a microcapsule-containing oil-based ink production technique (Japanese Patent Laid-Open No. 7-216273) already developed by the present inventors, and a transparent containing the microcapsules obtained by other techniques in a dispersed state When the ink film is formed on the surface of the sheet base material using ink, it is difficult to see with the naked eye under visible light. Fluorescence, the fluorescence was observed with the naked eye, and conceived the present invention found that the visible and generally to the uniform fluorescence entire ink film it through the capsule wall film.
[0006]
That is, the present invention is a character, number, figure, symbol, pattern, etc., formed on a predetermined part of the surface of a single piece sheet , with a transparent ink film having transparency under visible light and fluorescently developing under ultraviolet irradiation. a single piece sheet for preventing forgery that of comprising a secret information, transparent ink film is, is the anti-counterfeit sheet characterized by comprising a microcapsule of leuco dye Crystal violet lactone .
[0007]
The anti-counterfeit sheet of the present invention utilizes a fluorescent phenomenon of black light of an organic solvent containing a specific concentration range of CVL, and is produced by a known CVL microcapsulation technique in the field of pressure-sensitive copying paper. By printing the secret information with a transparent ink containing capsules dispersed in the ink vehicle, the secret information is difficult to see with the naked eye under visible light, but uniformly fluoresces with black light. . Further, when the secret information part is brought into contact with and pressed against a color developing sheet (developer coating sheet) of pressure-sensitive copying paper conventionally used, CVL is transferred to the developer and the color developing sheet Since it is colored, authenticity can be determined.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, although the structure of the anti-counterfeit sheet according to the present invention will be described in detail based on preferred examples, first, a method for preparing a CVL microcapsule-containing ink that forms a transparent ink film will be exemplified.
[0009]
[Method for preparing CVL microcapsule-containing ink]
A styrene maleic anhydride copolymer is dissolved together with a small amount of sodium hydroxide. In 200 parts of an aqueous solution containing 5% by weight of this solution, 6 parts of CVL is heated and dissolved in 194 parts of alkylnaphthalene, and dispersed to obtain an average particle size. An emulsion having a diameter of 1.8 μm was obtained. Next, 60 parts of a melamine-formalin prepolymer was added to the emulsion, and the temperature of the system was stirred at 75 ° C. for 2 hours to prepare an aqueous solution of 50% by weight of CVL microcapsules. Furthermore, 80 parts of this aqueous solution, 20 parts of glycerin, and 20 parts of UV curable varnish are added, while removing water by a method that combines vacuum distillation under predetermined conditions, and further 30 parts of a preparation for printing ink is added, The microcapsules were dispersed in a vehicle to prepare an ink containing CVL microcapsules.
[0010]
The CVL microencapsulation method in the present invention is not limited to the illustrated method, and may be based on a conventionally known encapsulation technique in the field of pressure-sensitive copying paper such as an in-situ method and an interfacial condensation polymerization method. The capsule particle size, the capsule wall thickness, etc. may be the same as those used in conventional pressure-sensitive copying paper, and there is no particular limitation. However, the CVL-containing concentration of the microcapsule core material in the organic solvent is required to be at least 2% by weight in order to sufficiently exhibit the fluorescence function, while the saturated concentration (normal temperature) with respect to the organic solvent in the capsule core material is required. ) Far exceeds CVL, and the fluorescence function cannot be efficiently extracted. Furthermore, it is not preferable to exceed 5% by weight from the relationship with the solubility in the organic solvent constituting the core substance, or the cost, etc. Therefore, the range of 2 to 5% by weight is necessary, preferably It is 2.5 to 3.5% by weight, more preferably around 3% by weight.
[0011]
Next, as for the technique related to the method for preparing an ink for CVL microcapsule, the exemplified method is based on the inventor's microcapsule-containing oil-based ink manufacturing technique (JP-A-7-216273). In the present invention, Without being limited to this method, a conventionally known inking preparation technique may be used. However, an exemplary method with good capsule dispersibility in the vehicle is most suitable for suitable printing performance of the secret information, or in order to make the secret information fluoresce preferably and uniformly when irradiated with black light. The transparent ink film in the present invention is not limited as long as the ink film formed on the surface of the single-piece sheet has transparency to the extent that it is difficult to visually recognize, even when the ink itself is somewhat colored. Is.
[0012]
Hereinafter, the example of the anti-counterfeit sheet according to the present invention will be described in detail as a promissory note. Here, FIG. 1 is a schematic perspective view of the promissory note, and FIG. 2 is a sectional view taken along line XX of FIG. FIG. 3 is a schematic explanatory view of an authenticity determination method using black light for the promised bill of FIG. 1, and FIG. 4 is a schematic explanatory view of an authenticity determination method using a coloring sheet for the promised bill of FIG. FIG. 5 is a schematic explanatory view of the secret information mode transferred to the developer coating surface of the color developing sheet of FIG.
[0013]
First, as shown in FIGS. 1 and 2, the promissory note 1 of the present embodiment has a single piece sheet for preventing counterfeiting having predetermined information A such as an amount column, a payee information column, a payer information column, etc. Secret information B consisting of “# 123 *” composed of numerals and symbols printed and formed with the CVL microcapsule-containing transparent ink exemplified above by a normal printing means on a predetermined portion of the surface 3 of 2 It is something that has been applied. And since this secret information B is comprised with the transparent ink membrane | film | coat, visual recognition with the naked eye is very difficult under visible light.
[0014]
There are two methods for determining the authenticity of the promissory note 1. That is, as shown in FIG. 3, when the surface 3 of the promissory note 1 is irradiated with black light (wavelength 370 nm) by the ultraviolet irradiation device E, the secret information B is fluorescent and “# 123 *” can be visually recognized. . When the ultraviolet irradiation device is not used, the bottom portion of the writing instrument P while contacting the secret information B with a color developing sheet S (developer coating sheet) of commercially available pressure-sensitive copying paper as shown in FIG. As shown in FIG. 5, the secret information B is transferred to the color developer coating surface 4 of the color developing sheet S, and a mirror image B ′ of “# 123 *” is formed in color. In addition to the present embodiment, the secret information B may be simply a simple figure such as a rectangle or a circle. In this case, the presence or absence of coloring may be confirmed simply by rubbing the coloring sheet.
[0015]
【The invention's effect】
As described above, the anti-counterfeit sheet of the present invention is a transparent ink in which CVL microcapsules manufactured by a encapsulation technique known in the field of pressure-sensitive copying paper are contained in an ink vehicle in a dispersed state. Since the secret information is printed, the secret information is difficult to see with the naked eye under visible light, but is uniformly fluorescent when irradiated with black light. Furthermore, since the colored sheet is colored when it is rubbed against the colored sheet of the pressure-sensitive copying paper that has been used in the past, the colored sheet will be colored. The authenticity can be easily determined even in a place where the apparatus has not been used or when the apparatus has failed.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a promissory note which is an example of an anti-counterfeit sheet according to the present invention.
2 is a cross-sectional view taken along line XX in FIG.
FIG. 3 is a schematic explanatory diagram of an authenticity determination method using black light for the promissory note of FIG. 1;
4 is a schematic explanatory diagram of a method for determining authenticity using a color developing sheet for the promissory note in FIG. 1;
5 is a schematic explanatory view of a secret information mode transferred to a developer application surface of the color developing sheet of FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sheet for forgery prevention 2 Single piece sheet 3 Single piece sheet surface A Predetermined information B Secret information B 'Mirror image of confidential information E Ultraviolet irradiation device S Color development sheet

Claims (1)

In a predetermined part of the surface of the single piece sheet , it has confidential information such as letters, numbers, figures, symbols, patterns, etc., formed with a transparent ink film that is transparent under visible light and fluorescently develops under ultraviolet irradiation. A forgery-preventing sheet, wherein the transparent ink film contains microcapsules of a leuco dye crystal violet lactone.

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