JP2001207398A - Paper for preventing counterfeit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper for preventing counterfeit of which a genuine material and a counterfeit material can clearly be distinguished by using a simple device by arranging a pigment capable of providing different colors by light sources on a part or the whole of one surface of a paper substrate. SOLUTION: This paper 1 for preventing the counterfeit has a counterfeit- preventing layer 12 containing a simple substance of a lanthanoid rare earth element or a compound thereof at least on a part or the whole of the one surface of the base paper 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to paper used for various kinds of goods including securities and the like which require forgery prevention, and more particularly, to forgery and offset by a color copier, a personal computer printer and the like. The present invention relates to an anti-counterfeiting paper that can be easily identified as authentic even if advanced counterfeiting that has been finely restored by a printing method or the like is attempted.

[0002]

2. Description of the Related Art In recent years, copiers, especially color copiers, have made great strides in terms of functionality, and these copiers (copiers) and color copiers (color copiers) have been used for securities. Such printed materials are frequently copied and misused, which has become a problem.

In view of these problems, counterfeiting prevention techniques employing copy prevention means utilizing characteristics of a copying machine have been developed in response to these problems. For example, this type of anti-counterfeiting means uses a colorant ink that has a sharp peak in the spectral reflection curve, prints the image, and reproduces a different color tone by color copying the image. By providing a halftone dot of a size less than the limit and combining this halftone dot with a halftone dot that can be resolved by a copying machine,
By making the original image unreproducible or by changing part of the lines that make up the image to a direction that does not overlap the scanning direction due to the scanning of the copier, only the lines that are in different directions appear to be raised during copying There are some that form an image, and those that combine a halftone dot and a line and reproduce the image when the difference between the halftone dot and the line is emphasized when copied. Could be done.

Furthermore, micro-characters are provided below the resolution of the copier, and the micro-characters are crushed during copying, making it difficult to completely reproduce the characters. In addition, at least a part of the printed image is made of magnetic ink. Since the magnetic ink portion is not reproduced in the copy, it is possible to determine the authenticity by detecting the presence or absence of this magnetic component, and the color to be observed according to the visual angle to the print By providing an image made of ink which causes a change in color (color shift), an image which cannot be reproduced in a copy, and an image made of black ink having no absorption in an infrared region is provided, and an infrared ray in a black portion of the copy is provided. By detecting the presence or absence of absorption, it is possible to determine the authenticity, such as in characters, images, designs, etc. with special ink It was such that discriminates authenticity by the presence or absence of the detection of.

[0005] However, improvement in resolution due to recent advances in copiers and color copiers has made it possible to reproduce the resolution and hue of images, which have been considered difficult in the past.
There has been a problem that the effect of the above-described forgery prevention technology is being lost. In addition, when a magnetic ink, which is a special ink, is used, there is a disadvantage that the authenticity cannot be determined without using a measuring unit having a magnetic head and a magnetic sensor. In order to enable the determination, it is important that there is a clear difference that is easier to determine, and it has been desired to provide such a determination means.

On the other hand, as a means for preventing forgery, there are a method of performing forgery prevention on the paper itself and a method of providing a thread on a part of the paper as the forgery prevention paper, instead of the above-described printing or the like. For example, Japanese Utility Model Application No. 58-168
As proposed in Japanese Patent Publication No. 754, a proposal is made to provide a bright plate such as aluminum foil or the like with a remarkable metallic color on the upper surface of the base paper, and to provide a character pattern on the surface of the bright plate to make the paper uncopyable by a copying machine. There is. Also, Japanese Patent Application Laid-Open No. 7-56377
As disclosed in Japanese Unexamined Patent Application Publication, there is an anti-counterfeit paper in which a pearl pigment-coated paper is formed by applying a coating liquid mainly composed of a pearl pigment and a binder, and the pearl pigment-coated paper is provided in a thread.

[0007]

However, even in the case of the forgery prevention paper as described above, the improvement in image resolution and color reproducibility due to the progress of copiers and color copiers has not been improved.
Since it has become possible to reproduce images and colors, which has been difficult in the past, there has been a problem that the effect of the above-described forgery prevention technology is being lost.

The present invention has been made to solve the problems and demands of the prior art. The object of the present invention is to provide a pigment which appears to have a different hue depending on the light source over the entire or partial space between paper substrates. An object of the present invention is to provide an anti-counterfeiting paper which can clearly identify a genuine product and a counterfeit product by using a simple device.

[0009]

According to the present invention, in order to attain the above object, according to the first aspect of the present invention, at least a part or all of one side of a paper base material contains a simple substance of a lanthanoid rare earth element or a lanthanoid rare earth element. Wherein the compound of formula (1) is contained.

[0010] In the invention according to claim 2, the compound is a compound selected from oxides, carbides, chlorides, fluorides, sulfides and nitrides. It was used as prevention paper.

According to a third aspect of the present invention, there is provided the anti-counterfeit paper according to the first or second aspect, wherein the compound is an oxide of any one of Ho, Nd and Pr.

According to the first, second or third aspect of the present invention, the lanthanoid rare earth element alone or a compound thereof contained in a part or all of one surface of the paper base varies depending on the type of light source. Since it looks like a color, it can be made a forgery prevention paper that is easy to determine authenticity. Also,
At the same time, the color of the paper changes reversibly depending on the light source,
It can also be used as decorative paper.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an explanatory view showing one embodiment of the forgery prevention paper of the present invention in a side cross section. FIG. 2A shows another embodiment of the forgery prevention paper of the present invention. FIG. 2B is a side sectional view of the forgery prevention sheet of FIG. 2. FIG. 3 is a plan view showing still another embodiment of the forgery prevention paper of the present invention.

The forgery prevention paper of the present invention is a forgery prevention paper (1) in which a forgery prevention layer (12) is provided on one entire surface of a base paper (11) as shown in the plan view of FIG. FIG. 2 shows a forgery prevention sheet according to another embodiment of the present invention.
As shown in the plan view of (a), the anti-counterfeit paper (1) is provided with, for example, a slit-shaped anti-counterfeit layer (14) on one side of a base paper (11). As the prevention paper, as shown in the plan view of FIG.
The anti-counterfeit paper (1) provided with, for example, a random pattern anti-counterfeit layer (16) on one side of (1).

The base paper (11) constituting the forgery prevention paper (1) of the present invention is softwood bleached kraft pulp (NBK).
P), hardwood bleached kraft pulp (LBKP), softwood bleached sulphite pulp (NBSP), thermomechanical pulp (TMP), and other papermaking pulp, with a dry paper strength enhancer, wet paper strength enhancer, and sizing agent , Fixing agent, retention improver, drainage improver, defoamer, dye, coloring pigment,
Papermaking is performed using a known paper machine such as a fourdrinier machine or a circular net machine, using a fluorescent agent or the like as appropriate. It is also possible to coat starch, polyvinyl alcohol, etc. on the paper surface during the papermaking process. This method is effective in improving the adhesion between the paper and the conductive layer. Further, if necessary, a machine calendering treatment or a super calendering treatment is performed to appropriately improve the surface smoothness.

The anti-counterfeit layers (12, 14, 16) constituting the anti-counterfeit paper (1) of the present invention include La, C and La.
e, Pr, Nd, Pm, Sm, Eu, Gd. Tb, D
It is composed of a simple substance of a lanthanoid rare earth element selected from y, Ho, Er, Tm, Yb and Lu, or a material containing a compound of these elements. Where the compound is
It is a compound selected from oxides, carbides, chlorides, fluorides, sulfides and nitrides. More specifically, for example, La ₂ O ₃ , LaCl ₃ , La (CO ₃ ) ₃ , LaF ₃ ,
CeO ₂ , Ce (SO ₄ ) ₂ , Ce ₂ (CO ₃ ) ₃ , Pr ₆ O
₁₁ , PrCl ₃ , Nd ₂ O ₃ , NdCl ₃ , Nd ₂ (CO ₃ )
₃ , NdF ₃ , Pm ₂ O ₃ , Sm ₂ O ₃ , SmCl ₃ , Eu ₂ O
₃ , EuCl ₃ , Gd ₂ O ₃ , GdF ₃ , Tb ₄ O ₇ , Dy ₂ O
₃ , Dy ₂ (CO ₃ ) ₃ , Dy (NO ₃ ) ₃ , Ho ₂ O ₃ , Er
₂ O ₃ , Er ₂ (CO ₃ ) ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , Lu ₂ O
_{3 and the} like can be selected as appropriate according to the purpose and the like.

When the particle size of the compound (material) of the lanthanoid-based rare earth element is 10 to 1000 nm, a larger color change occurs, which is preferable as an effect of preventing forgery and the like.

The forgery prevention layer (12,
In forming (14, 16), the above-mentioned material such as a lanthanoid-based rare earth element compound, a binder, a dispersant and an auxiliary agent are mixed on one surface and the surface of a base paper (11) as a forgery prevention ink. Alternatively, it can be formed by a printing method. For example, as shown in the side sectional view of FIG.
When the forgery prevention layer (12) is formed on the entire surface of 1), it can be formed by a gravure coating method, a roll coating method, or the like. As shown in FIGS. When the slit-like forgery prevention layer (14) is formed in (11), it can be formed by a gravure printing method, a screen printing method, or the like. This slit-shaped forgery prevention layer (14)
In consideration of the size of an article using this paper, for example, securities, it is necessary to provide an interval such that one slit-shaped forgery prevention layer (14) exists in at least one sheet of securities. is there. Also, as shown in the plan view of FIG.
Forgery prevention layer of random pattern on base paper (11) (16)
Can be formed by a gravure printing method, a screen printing method, or the like, as in the case of the slit shape.

Further, the paper may be made by mixing the above-mentioned materials such as the lanthanoid-based rare earth element compound with a sizing agent, a fixing agent, a coloring pigment, a fluorescent agent and the like at the time of paper making of the base paper (11).

In the case of the coating or printing method as well as the case of the above-mentioned paper making, the forgery prevention layer (12, 14, 1) is used.
6) From the top, machine calendar processing or super calendar processing is performed, and printing is performed so that the base paper (11) and the slit-shaped forgery prevention layer (14) are on the same plane, for example, as shown in FIG. Improving the surface smoothness in consideration of an appropriate surface is also appropriately performed.

The lanthanoid-based rare earth elements or their compounds constituting the anti-counterfeit layers (12, 14, 16) have visually different hues under light sources of different wavelengths. For example, taking Ho ₂ O ₃ as an example,
Under the sunlight, it looks pale yellow to the human eye, and it is a three-wavelength fluorescent lamp, more specifically, a wavelength of 450 nm (blue) and 540 nm.
Irradiation with light that emits light in three wavelength ranges of (green) and 610 nm (red), that is, under this light, human eyes appear pink.

The lanthanoid rare earth element has electrons in the 4f orbit, and absorbs a large amount of light having a wavelength in a narrow band in the visible region, and does not absorb much light having a wavelength outside the band. These characteristics are the same even for a lanthanoid-based rare earth compound.

As an example of this, FIG. 4 shows a spectral spectrum of Ho ₂ O ₃ which is a lanthanoid rare earth oxide.
As shown in this figure, Ho ₂ O ₃ has a wavelength of 450 nm and a wavelength of 55 nm.
It has sharp absorption bands around 0 nm and 650 nm. That is, Ho ₂ O ₃ absorbs a large amount of light in the above-mentioned wavelength range, but does not absorb much light of other wavelengths.
Therefore, the spectrum of the reflected light of Ho ₂ O ₃ when irradiated with the spectral wavelength of sunlight as shown in FIG. 5 is almost the same as the spectral spectrum of FIG. 4 and looks pale yellow.
450 nm, 540 nm, 610 nm as shown in FIG.
When irradiating Ho ₂ O ₃ with a three-wavelength fluorescent lamp of
Emission of 450 nm which is blue wavelength and 54 which is green wavelength
Since the light of 0 nm is absorbed by Ho ₂ O _3, only the light of 610 nm, which is the red wavelength, is reflected and looks like pink.

For this reason, for example, a color copier
At Ho_TwoO_ThreeCopies printed with ink containing
Then, each R (red) and G (grid) of the color copier
Green) due to the characteristics of B (blue) filter
Or it is copied in pale yellow. In this way, the forger is one
It looks like a similar paper is obtained,
450nm, 540nm, 610nm three wavelength emission type
Under fluorescent light, Ho _TwoO_ThreeGenuine paper contains
It looks dark, but the one copied by the color copier is
Copied because it looks pale green or pale yellow
That is, a forgery can be easily found.

That is, since the lanthanoid-based rare earth compound has the above-mentioned characteristics, it becomes a different color when irradiated with light sources having two or more kinds of spectral wavelengths in the same manner as described above.

Therefore, the authenticity of the anti-counterfeit paper (1) containing the lanthanoid-based rare earth compound of the present invention is determined by, for example, using a white light (52) close to sunlight, as shown in the schematic side view of FIG. 450nm, 540nm as above,
Using a simple judgment device equipped with a fluorescent lamp (50) of a 610 nm three-wavelength emission type, both light sources are alternately illuminated and viewed.
It will be possible to judge the truth immediately.

The forgery prevention paper (1) of the present invention as described above.
Can be used not only as paper for securities, tickets, etc., but also as wrapping paper for preventing forgery, and is also suitable as fancy paper with color-changing and excellent decorativeness depending on the light source.

[0029]

EXAMPLES The present invention will be described in detail with reference to specific examples.

<Example 1> A base paper consisting of the following [base paper composition] was adjusted to a paper layer having a basis weight of 90 g / m ² using a fourdrinier paper machine.
The paper was made to be. Thereafter, an anti-counterfeit ink composed of the following [composition of anti-counterfeit ink] is applied to the entire surface of the base paper by a microgravure method so as to have a dry weight of 15 g / m ² , and then subjected to a calendering treatment to obtain the anti-counterfeit paper. Obtained. [Composition of base paper] Softwood bleached kraft pulp (NBKP) 20 parts by weight Hardwood bleached kraft pulp (LBKP) 80 parts by weight White clay 10 parts by weight Paper strength enhancer 0.3 parts by weight Sizing agent 1 part by weight The above NBKP and LBKP are 350 mlC. . S. F, beaten it with clay, paper strength agent (trade name "Polystron 1").
91 "manufactured by Arakawa Chemical Industry Co., Ltd., a sizing agent (trade name" Sazpine E "manufactured by Arakawa Chemical Industry Co., Ltd.), and an appropriate amount of a pH adjuster to adjust the stock. [Composition of anti-counterfeit ink] Acrylic resin (trade name “Vylon BR-116” manufactured by Toyobo Co., Ltd.) 10 parts by weight Solvent Toluene 40 parts by weight MEK 40 parts by weight Ho ₂ O ₃ 10 parts by weight

When a copy of the anti-counterfeit paper is made by a color copier, and the anti-counterfeit paper and the duplicate are viewed in sunlight, both appear pale yellow, but a three-wavelength fluorescent lamp. When viewed below, the anti-counterfeit paper appeared pink, but the duplicate appeared pale yellow, as viewed under sunlight. Therefore, it was easy to distinguish between authentic products and duplicate products.

<Example 2> A base paper consisting of [base paper composition] used in Example 1 was formed using a fourdrinier paper machine so that the basis weight of the paper layer became 90 g / m ² . Thereafter, a dry weight of 15 g was obtained by a gravure printing method using a forgery prevention ink composed of the same [forgery prevention ink composition] as in Example 1.
/ M ² , a slit-like forgery prevention layer (14) was formed on the base paper (11) as shown in FIG. 2 (a), and thereafter a calender treatment was performed to obtain a forgery prevention paper (1).

When a copy of the above forgery prevention paper (1) is made by copying with a color copier, and the forgery prevention paper and the copy are viewed under sunlight, both of the forgery prevention portions have a slit pattern shape. It looks pale yellow, but when viewed under a three-wavelength fluorescent lamp, the anti-counterfeit paper looks pink with a slit pattern in the anti-counterfeit area, and the duplicate is pale yellow as it does under sunlight. And it was easy to distinguish the authentic product from the duplicate product.

[0034]

As described above, the present invention has the following effects. That is, the entire surface or a part of one side of the paper substrate contains a lanthanoid rare earth element or a compound thereof that absorbs a large amount of light having a wavelength in a narrow band in the visible region and does not absorb much light having a wavelength outside the band. By forming a layer, two layers having different spectral characteristics can be obtained.
Anti-counterfeit paper that exhibits different hues when viewed under more than one type of light source can be used, and by using the anti-counterfeit paper of the present invention, authenticity can be determined by a simple judgment machine.

Further, since the color of the paper is reversibly changed by the light source, the paper can be used as fancy paper having decorativeness.

Accordingly, the present invention exhibits an excellent practical effect as a forgery prevention sheet used in various fields, such as securities, tickets, admission tickets, as well as wrapping paper.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a forgery prevention sheet of the present invention.

FIG. 2 shows another embodiment of the forgery prevention paper of the present invention, in which (a) is a plan view and (b) is a side sectional view thereof.

FIG. 3 is a plan view showing still another embodiment of the forgery prevention sheet of the present invention.

FIG. 4 is a graph showing a representative spectral waveform of an anti-counterfeit ink constituting the anti-counterfeit paper of the present invention.

FIG. 5 is a graph showing a relative energy ratio at each wavelength of sunlight.

FIG. 6 is a graph showing a relative energy ratio at each wavelength of the lamp for authenticity determination according to the present invention.

FIG. 7 is a schematic side view for explaining an example of a device for authenticity determination according to the present invention.

[Explanation of symbols]

 1 anti-counterfeit paper 11 base paper 12 entire anti-counterfeit layer 14 slit anti-counterfeit layer 16 random anti-counterfeit layer 52 white light 54 three-wavelength fluorescent lamp

Claims (3)

[Claims] An anti-counterfeit paper characterized in that at least a part or all of one side of a paper substrate contains a simple substance of a lanthanoid-based rare earth element or a compound thereof. 2. The compound according to claim 1, wherein the compound is an oxide, a carbide, a chloride,
2. The forgery prevention paper according to claim 1, wherein the paper is a compound selected from fluoride, sulfide and nitride. 3. The forgery prevention paper according to claim 1, wherein said compound is an oxide of any of Ho, Nd and Pr.