JP2003089893A - Decoloring device, decoloring method, and forgery preventing and checking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely decolor a coloring agent without mixing any impurities (a second substance) in a base material in order to repeatedly recycle the base material with the coloring agent adhering thereto. SOLUTION: A decoloring device 5 decolors the coloring agent having chromophoric group including chain-like double bond, and has an anode 4 and a cathode 3 formed of a hydrogen occlusion metal, and further comprises a cell 1 to generate hydrogen atoms from the cathode 3 by the electrolysis and a cell 2 in which at least a part of the cathode 3 is exposed in the inside thereof. The coloring agent present in the cell 2 is subjected to the hydrogenolysis by hydrogen atoms passing through the cathode 3, and decolored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an erasing device for erasing a colorant attached to a substrate, a erasing method, and an anti-counterfeiting authentication method using the erasing method.

[0002]

2. Description of the Related Art In recent years, researches on recycling technology have been actively conducted in various fields from the viewpoint of environmental protection and resource saving. Among them, as a method of decoloring the colorant attached to the substrate in order to recycle the substrate such as paper that has been once printed or colored, there is a method of using a boron salt of a cationic dye as the colorant. Specifically, by irradiating the paper printed with this colorant with near-infrared light, the printed portion is erased. However, the substrate colored and printed with the above colorant has a property that the colorant absorbs near-infrared light, and therefore, against sunlight or white lamps containing near-infrared light. However, there is a problem of fading. In addition, there is a problem that the colorant cannot be completely decolored and the color remains even when the printed and colored substrate is irradiated with near infrared light.

Therefore, in JP-A-8-199485, a colorant containing a cationic dye as a main component is printed, and a colored substrate is coated with a reducing agent solution such as a borohydride compound or a hydrazine compound to erase the colorant. A method for erasing a colored coloring composition is disclosed. That is, by using a colorant containing a cationic dye as a main component, fading due to near infrared light is prevented. In addition, the erasing method of the above-mentioned publication can be easily erased without much residual color as compared with the above-described erasing method of irradiating near infrared light.

[0004]

However, in the above-mentioned conventional structure, since the reducing agent solution which is the second substance other than the colorant is applied, the purity of the base material is lowered and the base material is repeatedly recycled. There is a problem that it is not suitable for.
Further, since a reducing agent solution which is a chemical is used, there is a problem in safety in handling.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is, for example, to make it possible to repeatedly recycle a base material, a colorant attached to the base material is used as an impurity (first An object of the present invention is to provide an erasing device capable of safely erasing without mixing two substances), an erasing method, and an anti-counterfeiting authentication method using the erasing method.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have focused on an azo dye or azo pigment having a diazo group in the structure as a colorant, and at least It was found that continuous erasing is possible by printing or coloring with a colorant mainly composed of an azo dye or azo pigment, and by contacting the base material on which the colorant is attached with atomic hydrogen, continuous erasing is possible. The invention was completed. Furthermore, the present inventors take advantage of the fact that the product (colorant) after decolorization absorbs ultraviolet rays, and it has a new added value that even if it is visually colorless, it can be irradiated with ultraviolet rays and the reflected light can be confirmed. I found it.

That is, the erasing device according to the present invention is, in order to solve the above problems, a erasing device for erasing a colorant having a chromophore containing a chain-like double bond, which comprises: ,
A cathode comprising a hydrogen storage metal, comprising a first cell for generating hydrogen atoms in the cathode by electrolysis and a second cell in which at least a part of the cathode is exposed inside; The colorant existing in the second cell is hydrolyzed by the hydrogen atoms passing through the cell to be decolored.

According to the above structure, when, for example, water is put into the first cell and electrolysis is performed, hydrogen is stored in the cathode of the hydrogen storage metal. Eventually, hydrogen atoms that cannot be fully occluded are generated as hydrogen atoms from the back surface of the electrode, that is, the surface of the cathode on the second cell side. When a colorant having a chromophore containing a chain-like double bond comes into contact with the surface of such a cathode, the colorant is hydrolyzed and decolorized. This is because hydrogen is generated in the state of atoms having a strong reducing power on the surface of the cathode. That is, in a colorant in which the chromophore contains a chain-like double bond, for example, when the chromophore is an azo group (-N = N-), the hydrogen atom generated from the cathode causes hydrogenolysis as described below. To color.

-N = N- + 4H → -NH ₂ + H ₂ N- Further, for example, the chromophore has a vinylene group (-CH = CH-).
In the case of 1, the hydrogen atoms generated from the cathode are hydrolyzed and decolorized as follows.

The [0010] _{-CH = CH- + 4H → -CH 3} + H 3 C- this, the substances other than the colorant, which is decomposed in the second cell will not be mixed, for example, colorant adheres The existing base material is not contaminated. As a result, the base material can be repeatedly recycled. Further, since the second substance such as a reducing agent solution which has been conventionally used for decoloring the colorant is not required, the color can be safely decolorized.

Further, the decoloring device according to the present invention is characterized in that, in addition to the above-mentioned constitution, a platinum film is formed on the surface of the cathode.

According to the above structure, since the platinum film having a low overvoltage against the electrolysis reaction is formed on the surface of the cathode by, for example, the plating treatment, many hydrogen atoms can be generated and the coloring agent The efficiency of erasing can be improved.

Further, in addition to the above structure, the erasing apparatus according to the present invention further comprises a contact member for contacting the base material having the colorant attached thereto with the cathode exposed inside the second cell, It is characterized in that it is provided with a carrying member for carrying the base material.

According to the above construction, the base material can be continuously fed to the cathode and brought into contact with the cathode, so that the decoloring treatment can be continuously carried out. As a result, the color erasing process of the base material can be performed quickly.

On the other hand, the color erasing method according to the present invention is a color erasing method for erasing a colorant having a chromophore containing a chain double bond in order to solve the above-mentioned problems, The method is characterized by including at least a step of generating hydrogen atoms in the cathode by means of and a step of hydrolyzing and decoloring the colorant by the hydrogen atoms passing through the cathode.

According to the above method, when the colorant having a chromophore containing a chain-like double bond comes into contact with the surface of the cathode, the colorant is hydrolyzed and erased by hydrogen atoms having a strong reducing power. That is, in the above colorant, for example, when the chromophore is an azo group (-N = N-), it is hydrolyzed and erased by hydrogen atoms generated from the cathode as follows.

-N = N- + 4H → -NH ₂ + H ₂ N- Further, for example, the chromophore is a vinylene group (-CH = CH-).
In the case of 1, the hydrogen atoms generated from the cathode are hydrolyzed and decolorized as follows.

[0018] By _{-CH = CH- + 4H → -CH 3} + H 3 C- this, conventionally, a second material such as a reducing agent solution which has been used for decoloring the colorant be unnecessary Therefore, it can be safely erased.

Further, the forgery prevention authentication method according to the present invention is
A colorant having a chromophore containing a chain double bond and a benzene ring or a condensed ring attached to a base material is generated by electrolysis, and is hydrolyzed by a hydrogen atom passing through the cathode to be decolorized. It is characterized by including at least a step and a step of irradiating the decolored substrate with ultraviolet rays.

According to the above method, the product after being decolorized has a benzene ring or a condensed ring having a property of absorbing light in the ultraviolet region. Thereby, when the decolored base material is irradiated with ultraviolet rays, the product absorbs the light and the decolorized portion can be highlighted. That is, it is possible to visually confirm the printed (adhered) content, then erase the color, visually make it colorless, irradiate ultraviolet rays when authenticity authentication is required, and confirm the printed content by the reflected light.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Regarding one embodiment of the present invention,
It will be described below with reference to FIG. FIG. 1 shows a cross-sectional view of an erasing device 5 according to an embodiment of the present invention. As shown in the figure, the erasing device 5 has a cell 1 (first cell) and a cell 2 (second cell). A cathode 3 made of a hydrogen storage metal is formed on a common wall (separator) that separates the cell 1 and the cell 2, and an anode 4 is formed on the opposite side of the cathode 3 on the cell 1 side. Water in cell 1
And, if necessary, the electrolyte is filled, and the cell 2 is filled with water containing a coloring agent, for example, a dye. Then, by applying a voltage between the cathode 3 and the anode 4, the water contained in the cell 1 is electrolyzed.

Some hydrogen atoms (H) generated on the surface of the cathode 3 on the cell 1 side are released as hydrogen molecules (H ₂ ) on the electrode surface, while the remaining hydrogen atoms are emitted to the cathode 3. It is occluded. When the cathode 3 eventually becomes unable to store hydrogen atoms, the hydrogen atoms that cannot be stored are generated on the back surface of the electrode, that is, on the surface of the cathode 3 on the cell 2 side, and released as hydrogen molecules. When the colorant touches the surface of the cathode 3 as described above, the touched colorant is hydrolyzed and erased. This is because hydrogen is generated in the state of atoms having a strong reducing power on the surface of the cathode 3. Since the hydrogen atoms continue to be generated as long as the water in the cell 1 is electrolyzed, the decoloring process can be continuously performed.

The cathode 3 applied to the decoloring device 5 may be any one capable of occluding hydrogen by electrolysis of water and providing hydrogen from the back side, and the kind thereof is not limited, but the hydrogen occluding metal palladium is used. (Pd) is more preferable. Furthermore, it is more preferable to form a platinum film having a low overvoltage on the surface of the cathode 3 against the hydrogen generation reaction, specifically, to plate platinum. Specifically, it is preferable that the surface of the cathode 3 is plated with platinum black, which allows a large number of hydrogen atoms to be generated. That is, the efficiency of decoloring the colorant can be improved. On the other hand, the anode 4
The type is not particularly limited, but a nickel plate or the like is suitable. Further, in order to generate more hydrogen atoms from the cathode 3, the contact area of the anode 4 in contact with the water contained in the cell 1 is preferably larger than the contact area of the cathode 3.

The type of the electrolyte of the cell 2 is not limited, because water is basically electrolyzed in the cell 1. For example, potassium hydroxide, sodium hydroxide, hydrochloric acid and the like can be used, but potassium hydroxide is more preferable. Among them, the molar concentration is 6M
(Mol / l) aqueous potassium hydroxide solution is more preferred.

Next, the colorants applicable to the erasing device 5 will be described below. However, the colorant applicable to the above-described decoloring principle is not limited to these, and the present invention can be applied to a colorant in which the chromophore itself contains a chain double bond. For example, the chromophore is an azo group (-N = N-)
In the case of 1, the hydrogen atoms generated from the cathode 3 are hydrolyzed in the following manner to generate an amine and decolorize.

-N = N- + 4H → -NH ₂ + H ₂ N- When the chromophore is a vinylene group (-CH = CH-),
The hydrogen atoms generated from the cathode 3 are hydrolyzed as described below to generate a methyl group and decolorize.

[0027] _{-CH = CH- + 4H → -CH 3} + H 3 C- Incidentally, only a limited double bond azo group of the chromophore (-N = N-) or vinylene group (-CH = CH-) However, the present invention is not applicable to a colorant having a chromophore itself which is cyclic, for example, a colorant having a benzene ring or a condensed ring as a chromophore. The decolorizable dyes and pigments are listed below.

Examples of dyes include monoazo dyes such as Amaranth and Orange II, disazo dyes such as metanil yellow and tartrazine, basic dyes such as Bismark Brown G and chrysoidine, Acid Alizarin Red B, Krome Blue B, Krome Yellow GG and Metachrome. Acid mordant dyes such as Black Blue G, Direct Black BH,
Examples include disperse dyes such as Sirius Supra Blue 6G, Sirius Yellow GC, Chloranthine Green BLL, Chrysophenin G, Sirius Supra Yellow RT, Benzofast Copper Blue F3GL, and Sirius Red Violet RL.

Azoic dyes such as Variamine Blue Salt B, Fast Red Salt G, Procion Yellow RS, Tipaclone Brilliant Red B, Remazol Brilliant Violet 5R and Oil Red IV.
Oil-soluble dyes such as Indigo, Brom Indigo 4
B, vat dyes such as thioindigo, stilbene dyes such as Blancophore B, and nitro dyes such as Uvitex ER.

On the other hand, in the case of pigment, Pigment Red 48:
1, Pigment Red 48: 2, Pigment Red 4
8: 3, Pigment Red 48: 4, Pigment Red 48: 5, Pigment Red 52: 1, Pigment Red 52: 2, Pigment Red 57: 1, Pigment Red 58: 2, Pigment Red 58: 4, Pigment Red 63: 1, soluble red azo pigments such as Pigment Red 63: 2, Pigment Red 64, Pigment Red 64: 1, Pigment Red 200 and Pigment Brown 5.

Pigment Yellow 1, Pigment Yellow 2, Pigment Yellow 3, Pigment Yellow 5, Pigment Yellow 6, Pigment Yellow 4
9, Pigment Yellow 65, Pigment Yellow 7
3, Pigment Yellow 74, Pigment Yellow 7
5, Pigment Yellow 97, Pigment Yellow 9
8, Pigment Yellow 111, Pigment Yellow 1
16, pigment yellow 130, pigment orange 1 and other monoazo yellow pigments.

Pigment Yellow 61, Pigment Yellow 62: 1, Pigment Yellow 133, Pigment Yellow 168, Pigment Yellow 169, Pigment Yellow 100, Pigment Yellow 183,
Pigment Yellow 190, Pigment Yellow 191
And β-naphthol pigments such as Pigment Orange 2, Pigment Orange 5, Pigment Red 1, Pigment Red 3, Pigment Red 4, Pigment Red 6 and the like.

Pigment Red 49, Pigment Red 49: 1, Pigment Red 49: 2, Pigment Red 49: 3, Pigment Red 50: 1, Pigment Red 51, Pigment Red 53, Pigment Red 53: 1, Pigment Red 68. Pigment Orange 17, Pigment Orange 17: 1, Pigment Orange 46, and the like.

Pigment Yellow 120, Pigment Yellow 151, Pigment Yellow 154, Pigment Yellow 175, Pigment Yellow 180, Pigment Yellow 181, Pigment Yellow 194,
Benzimidazolone pigments such as Pigment Orange 36, Pigment Orange 60, Pigment Orange 62, Pigment Red 171, Pigment Red 175, Pigment Red 176, Pigment Red 185, Pigment Red 208, Pigment Violet 32 and Pigment Brown 25 are also included.

Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 55, Pigment Yellow 63, Pigment Yellow 81, Pigment Yellow 83, Pigment Yellow 87, Pigment Yellow 90, Pigment Yellow 106, Pigment Yellow. Yellow 113, Pigment Yellow 114, Pigment Yellow 121, Pigment Yellow 124, Pigment Yellow 126, Pigment Yellow 127, Pigment Yellow 136, Pigment Yellow 152, Pigment Yellow 170, Pigment Yellow 171, Pigment Yellow 172, Pigment Yellow 174, Pigment Yellow 176. , Pigment Yellow 188, Pigment Orange 5, Pigment Orange 16, Ziz azo yellow pigments such as Pigment Orange 44 and the like.

Pigment Orange 13, Pigment Orange 34, Pigment Red 37, Pigment Red 38, Pigment Red 41, Pigment Red 1
Pyrazolone pigments such as 11, Pigment Yellow 93,
Pigment Yellow 94, Pigment Yellow 95, Pigment Yellow 128, Pigment Yellow 166,
Pigment Orange 31, Pigment Red 144, Pigment Red 166, Pigment Red 214, Pigment Red 220, Pigment Red 221, Pigment Red 242, Pigment Brown 23 and other condensed azo pigments, Pigment Red 88, Pigment Red 1
Thioindigo pigments such as 81, Pigment Yellow 10
9, Pigment Yellow 110, Pigment Yellow 1
Other examples include isoindolinone pigments such as 73 and Pigment Orange 61.

Next, a decoloring device according to another embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a cross-sectional view of the erasing device 11 according to another embodiment of the present invention. As shown in the figure, the erasing device 11 has a cell 12 (first cell) and a cell 13 (second cell). A cathode 14 is formed on a common wall 18 that separates the cell 12 and the cell 13, and an anode 15 is formed on the opposite surface of the cathode 14 on the cell 12 side. The cell 12 is filled with water and optionally an electrolyte, and the cell 13 is filled with water. Then, by applying a voltage to the cathode 14 and the anode 15, the water contained in the cell 12 is electrolyzed. In order to generate more hydrogen atoms from the cathode 14, the contact area of the anode 15 in contact with water filled in the cell 12 is larger than the contact area of the cathode 14. Furthermore, on the cell 13 side,
A roller 17 (contact member, conveyance member) that is in contact with the cathode 14 is provided.

Some of the hydrogen atoms generated on the surface of the cathode 14 on the cell 12 side are released as hydrogen molecules on the electrode surface, while the remaining hydrogen atoms are absorbed by the hydrogen storage metal of the cathode 14. . Eventually, when the cathode 14 can no longer store hydrogen atoms, the hydrogen atoms are generated on the surface of the cathode 14 on the cell 13 side and are released as hydrogen molecules. In order to smoothly supply the hydrogen atoms from the surface of the cathode 14 on the cell 13 side, it is effective to fill the hydrogen atoms in the cathode 14 in advance by using night power before use.

When a colorant touches the surface of the cathode 14 as described above, the touched colorant is hydrolyzed and erased. In addition,
The decoloring device 11 uses a roller 17 in a water containing a base material 16 such as paper to which a colorant is attached by printing or coloring in a cell 13 by using a roller 17 as a method of bringing the colorant into contact with the cathode 14. Contact 14 to erase the color. Then, by rotating the roller 17, the base material 16 is conveyed in a fixed direction, and the colorant attached to the base material 16 is continuously fed to the cathode 14.
Contact with and erase the color.

That is, the roller 17 has a function as a contact member for bringing the base material 16 into contact with the cathode 14 exposed inside the cell 13, and a function as a transfer member for transferring the base material 16. A brush can also be mentioned as a structure of a contact member. However, the above two members are not limited to those integrally formed. That is, for example, only the contact member for contacting the base material with the cathode 14 is provided in the cell 13
A configuration may be used in which a transport member that is provided inside and that transports the base material 16 is provided outside the cell 13.

According to the structure of the decoloring device 11 as described above, no substance other than water is required on the cell 13 side, and therefore no substance other than the decomposed colorant is mixed. The material 16 is not contaminated. As a result, the base material 16 can be repeatedly recycled. Also,
Since a second substance such as a reducing agent solution which has been conventionally used for decoloring a colorant is not necessary, the color can be safely decolorized.

The material of the base material 16 is not limited to paper, and cloth, plastic, glass and the like are not limited, but the surface is preferably smooth. On the other hand, the cathode 14 only needs to be a portion that contacts the base material by the roller 17. Therefore, in the decoloring device 11, the cathode 14 may be provided on at least the portion of the wall 18 separating the cell 12 and the cell 13 that is in contact with the base material by the roller 17.

Next, a forgery prevention authentication method to which the erasing method according to the present invention is applied will be described below. For example, in the conventional technique, in Japanese Patent Laid-Open No. 6-227192,
A forgery prevention technique using infrared absorbing ink on a paper surface is disclosed. This is a colorless transparent infrared absorbing ink that prints certain information on a commuter pass. Not only is this information invisible, but it cannot be copied using a copying machine or the like. However, when this commuter pass is irradiated with infrared light, the reflected light can be detected and information can be confirmed. This makes it possible to distinguish between a genuine commuter pass and a forged commuter pass, and is a system that can prevent forgery.

On the other hand, a colorant applicable to the color erasing method according to the present invention, which has a benzene ring or a condensed ring in a structure other than the chromophore, is decolorized by the color erasing method according to the present invention. The product will have a benzene ring and a condensed ring. Further, a compound having a benzene ring or a condensed ring has a property of absorbing light in the ultraviolet region.

The forgery prevention authentication method according to the present invention uses the above properties. Specifically, first, a colorant having a benzene ring or a condensed ring on a structure other than the chromophore is attached to the substrate by printing or coloring, and the ink on the paper surface is erased by the erasing method according to the present invention. To do. Then, when the decolorized paper is dried and irradiated with ultraviolet rays, the product having a benzene ring or a condensed ring absorbs the light, and the decolorized portion can be highlighted. In other words, it is possible to visually confirm the adhered (printed) content, then erase the color, and irradiate with ultraviolet rays to confirm the authenticity when it is necessary.

[0046]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these as long as the gist thereof is not exceeded.

Example 1 Dye Amaranth (manufactured by Wako Pure Chemical Industries, see Chemical Formula 1) 0.1% by weight ion-exchanged water 99.9% by weight Dye amaranth and ion-exchanged water were mixed well in the above-mentioned ratio to obtain The colored aqueous solution is sprayed on plain paper (base material)
Was applied to. After drying for a whole day and night, it was cut into 50 mm × 50 mm to obtain a sample before erasing. As an erasing device,
The erasing device 11 (see FIG. 2) was used. 2 for the cathode 14
A palladium plate having a thickness of 0 mm × 55 mm and a thickness of 5 mm was used. The surface of the cathode 14 on the side of the cell 13, which is one side of the cathode 14, was plated with platinum black. On the other hand, a nickel plate is used as the anode, and the aqueous solution of the electrolyte has a molar concentration of 6 M (mol / mol
l) An aqueous solution of potassium hydroxide was used.

A current having a current density of 50 mA / cm ² was passed between the cathode 14 and the anode 15 of the decoloring device 11. After electrolyzing water for about 1 hour to fill the cathode 14 which is a palladium electrode with hydrogen, the sample before decoloring was brought into contact with the cathode 14 for an appropriate period of time. The decolorized sample was dried overnight and the brightness and hue were measured.

[0049]

[Chemical 1]

[Example 2] Pigment Novoperm Red F2RK 70-N (manufactured by Clariant, see Chemical formula 2) 0.5 wt% Solspers 20000 (Zeneca) 3.0 wt% diethylene glycol 10.0 wt% ethylene glycol-n -Butyl ether 4.0% by weight Ion-exchanged water 82.5% by weight Solsperse 20000, diethylene glycol, and the above components except ethylene glycol-n-butyl ether were mixed, and 20 kHz using an ultrasonic crusher (Nippon Seiki Seisakusho Co., Ltd.). The ultrasonic wave of was irradiated for 2 hours to disperse. Then, after stirring and mixing the remaining components, 0.4
A 5 μm membrane filter was used to obtain an aqueous colorant solution. This aqueous coloring agent solution was applied to plain paper in the same manner as in Example 1 to erase the color, and then the brightness of the sample
The hue was measured.

[0051]

[Chemical 2]

[Example 3] Decoloring was performed in the same manner as in Example 1 except that the cathode 14 was replaced with a non-plated palladium plate.

Table 1 shows the results of comparing the erasing speeds by measuring the optical densities in the above Examples 1 to 3. Specifically, the color erasing speeds of the colorants of Examples 1 to 3 were measured by measuring the C value (optical density) of the colorant with X-Rite 938 (manufactured by Nippon Lithographic Equipment Co., Ltd.). The half-life was compared.

[0054]

[Table 1]

From Table 1, comparing Example 1 and Example 3, it can be seen that the decoloring rate of the platinum black-plated cathode 14 is faster than that of the untreated cathode 14. I understand.

Example 4 A plain paper, which had been coated with an aqueous colorant solution and decolorized in the same manner as in Example 2, was irradiated with ultraviolet rays from a 200 W low-pressure mercury lamp, and its reflected light was confirmed. Then, I was able to reveal the latent image before erasing.

[0057]

EFFECTS OF THE INVENTION For example, by a decoloring device for decoloring a coloring agent such as a dye or a pigment adhered on a substrate with atomic hydrogen,
The reducing agent solution that was conventionally used to decolorize the colorant is no longer necessary. That is, the cells for erasing do not need anything other than water. Therefore, a base material such as paper or cloth can be reused repeatedly. Moreover, since water is electrolyzed as a source of atomic hydrogen, the additional cost is only water and electricity. Moreover, it has become possible to construct a forgery prevention system by utilizing the property of absorbing ultraviolet rays after the colorant has been erased.

That is, the color erasing device according to the present invention is a color erasing device for erasing a colorant having a chromophore containing a chain double bond as described above, and includes an anode and a hydrogen storage metal. And a second cell in which at least a part of the cathode is exposed inside, the first cell having a cathode made of The colorant existing in the second cell is hydrolyzed and decolored by the hydrogen atom.

Therefore, when, for example, water is put into the first cell and electrolyzed, hydrogen is occluded in the cathode of the hydrogen occluding metal, and eventually hydrogen atoms that cannot be occluded are stored in the cathode on the second cell side. Generated as hydrogen atoms from the surface of. When a colorant having a chromophore containing a chain-like double bond comes into contact with the surface of such a cathode, the colorant is hydrolyzed and decolorized. This is because hydrogen is generated in the state of atoms having a strong reducing power on the surface of the cathode.

As a result, a substance other than the decomposed colorant is not mixed in the second cell, so that, for example, the base material to which the colorant is attached is not contaminated. As a result, the base material can be repeatedly recycled. Further, since a second substance such as a reducing agent solution which has been conventionally used for decoloring a colorant is unnecessary, it is possible to safely decolor.

Further, the decoloring device according to the present invention has a structure in which a platinum film is formed on the surface of the cathode, in addition to the above structure, as described above.

Therefore, since a platinum film having a low overvoltage against the electrolysis reaction is formed on the surface of the cathode, many hydrogen atoms can be generated and the efficiency of decoloring the colorant can be improved. It has the effect of being able to.

Further, in the decoloring device according to the present invention, as described above, in addition to the above structure, the base material to which the coloring agent is attached is brought into contact with the cathode exposed inside the second cell. This is a configuration including a contact member and a transport member that transports the base material.

Therefore, since the base material can be continuously fed to the cathode and brought into contact with the cathode, the decoloring treatment can be continuously carried out. As a result, there is an effect that the color erasing process of the base material can be performed quickly.

On the other hand, the color erasing method according to the present invention is a color erasing method for erasing a colorant having a chromophore containing a chain double bond as described above. It is a method including at least a step of generating atoms and a step of hydrolyzing and decoloring a colorant with hydrogen atoms that have passed through the cathode.

Therefore, when the colorant having a chromophore containing a chain-like double bond comes into contact with the surface of the cathode, the colorant is hydrolyzed and erased by hydrogen atoms having a strong reducing power. This eliminates the need for a second substance such as a reducing agent solution that has been conventionally used for decoloring a colorant, and thus has the effect of safely decoloring.

Further, the forgery prevention authentication method according to the present invention is
A colorant having a chromophore containing a chain double bond and a benzene ring or a condensed ring attached to a base material is generated by electrolysis, and is hydrolyzed by a hydrogen atom passing through the cathode to be decolorized. And a step of irradiating the decolored substrate with ultraviolet rays.

Therefore, since the product after being decolorized has a benzene ring or a condensed ring having a property of absorbing light in the ultraviolet region, when the decolorized substrate is irradiated with ultraviolet rays. The product has an effect that it absorbs light and the decolorized portion can be highlighted.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an outline of an erasing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an outline of an erasing device according to another embodiment of the present invention.

[Explanation of symbols]

1 cell (first cell) 2 cells (second cell) 3 cathode 4 anode 5 Decoloring device 11 Decoloring device 12 cells (first cell) 13 cells (second cell) 14 cathode 15 Anode 16 Base material 17 rollers (contact member, transport member) 18 walls

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C25B 11/08 C25B 9/00 A

Claims (5)

[Claims] 1. A decoloring device for decoloring a colorant having a chromophore containing a chain-like double bond, the decoloring device having an anode and a cathode made of a hydrogen storage metal, wherein hydrogen is formed on the cathode by electrolysis. A first cell for generating atoms and a second cell in which at least a part of the cathode is exposed to the inside are provided, and a colorant present in the second cell is removed by a hydrogen atom passing through the cathode. An erasing device characterized by being hydrolyzed and erasing. 2. The decoloring device according to claim 1, wherein a platinum film is formed on the surface of the cathode. 3. A contact member for contacting a base material, to which a colorant is attached, with a cathode exposed inside the second cell, and a transfer member for transferring the base material. Item 1. The erasing device according to item 1 or 2. 4. A decoloring method for decoloring a colorant having a chromophore containing a chain double bond, the step of generating hydrogen atoms in the cathode by electrolysis, and the hydrogen atoms passing through the cathode. And hydrolyzing the colorant to erase the color. 5. A colorant having a chromophore containing a chain double bond and a benzene ring or a condensed ring attached to a base material is generated by electrolysis, and is hydrolyzed by hydrogen atoms passing through the cathode. The anti-counterfeiting authentication method is characterized by including at least a step of erasing and a step of irradiating the decolored base material with ultraviolet rays.