KR102585243B1 - Fluorescent ink composition for anti-counterfeit, method for preparing fluorescent ink composition, and security document preventing counterfeit using the ink composition - Google Patents

Abstract

A fluorescent ink composition for preventing forgery and alteration, a method for manufacturing the fluorescent ink composition, and a security document for preventing forgery and alteration prepared using the same are provided. The fluorescent ink composition includes a solvent; A colored first coloring material contained in the solvent, wherein the first coloring material is insoluble in the solvent; and at least one fluorescent second colorant contained in the solvent, wherein the second colorant is soluble in the solvent or has a higher solubility than the first colorant.

Description

Fluorescent ink composition for preventing forgery and falsification, method for producing fluorescent ink composition, and security document for preventing forgery and falsification using ink composition }

The present invention relates to an ink composition, a method for producing the ink composition, and a security document using the same. In detail, it relates to a fluorescent ink composition for preventing forgery and alteration, a method for manufacturing the fluorescent ink composition, and a security document for preventing forgery and alteration prepared using the same.

Recently, with the rapid development of high-level printing and image processing media, sophisticated imitation or reproduction of documents has become possible. The number of cases of misuse of this forgery technology for crimes is increasing, and various studies are being conducted to identify forgery or prevent forgery. Anti-counterfeiting technologies are being developed in various fields, but one of them is water-marking technology.

Examples of ink used in watermarking include thermosensitive ink, which changes the color of the ink when heated by heat, etc., and photosensitive ink, which changes color when exposed to light of a specific wavelength band. Even if it is a counterfeit document that is extremely similar in appearance under normal conditions, forged documents can be easily identified by determining color variation, such as color change or disappearance under specific conditions.

Republic of Korea Patent Publication No. 10-0517160

As a type of the photosensitive ink described above, an ink composition containing a fluorescent material is being developed. For example, Patent Document 1 discloses a fluorescent ink with dichroism using a plurality of fluorescent substances. Specifically, an ink composition capable of identifying copied documents is disclosed, including fluorescent inks of various colors and colored inks having a complementary color relationship with the fluorescent inks.

However, ink compositions containing conventional fluorescent substances have the problem of being impossible to apply to inks that exhibit black or black as a base color. Colors with a brightness (value) below a certain level that is black or close to black absorb light, making it difficult for the fluorescent material to exhibit fluorescence.

Due to this problem, inks containing conventional fluorescent substances can only be applied to inks that have a bright base color or high brightness, and even in this case, the fluorescence is weak. If more fluorescent substances are added to observe fluorescent colors more strongly, the coloring stability of the ink will decrease or the manufacturing cost will increase. In addition, since the basic colors of fluorescent ink that can be implemented are limited, the field of use is also limited.

An example of the black ink mentioned above is ink using ink. Ink is mainly used in fields such as calligraphy, but ink is also used to sign original works of art in place of the signature of the work of art.

Accordingly, the problem to be solved by the present invention is to provide a fluorescent ink composition that can be applied to basic color inks having a brightness that is black or close to black.

Another problem to be solved by the present invention is to provide a method for producing a fluorescent ink composition that can be applied to basic color inks having a brightness that is black or close to black.

Another problem to be solved by the present invention is to provide a security document to which the above fluorescent ink composition is applied.

The problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

A fluorescent ink composition according to an embodiment of the present invention for solving the above problems includes a solvent; A colored first coloring material contained in the solvent, wherein the first coloring material is insoluble in the solvent; and at least one fluorescent second colorant contained in the solvent, wherein the second colorant is soluble in the solvent or has a higher solubility than the first colorant.

The first coloring material may have a black color or a brightness of 20 or less.

The average particle size of the single particles of the first coloring material may be in the range of 40 nm to 80 nm, and the average particle size of the aggregate particles of the first coloring material may be in the range of 400 nm to 1,200 nm.

The first coloring material includes carbon black, and the content of the first coloring material may be 3.0% by weight to 12% by weight.

Additionally, the content of the second coloring material may be 0.01% by weight to 1.0% by weight.

In some embodiments, the solvent comprises a polar solvent, and the second colorant material comprises M ₃ [L(dpa) ₃ ], wherein M is an alkali metal element that is one of Li, Na, K, Rb, or Cs. and L may be a lanthanide element, one of Eu, Gd, Tb, Dy, or Er.

In some embodiments, the solvent includes a non-polar solvent, and the second coloring material may include porphyrazine, phthalocyanine, derivatives thereof, combinations thereof, and/or combinations of derivatives thereof. there is.

Additionally, the fluorescent ink composition may further include 0.1% to 5.0% by weight of animal protein.

In some embodiments, the fluorescent ink composition may not contain chloroform and polyvinyl alcohol.

A method for producing a fluorescent ink composition according to an embodiment of the present invention to solve the above other problems includes mixing a first coloring material insoluble in a solvent; and mixing a fluorescent second colorant material soluble in the solvent.

A document or security document according to an embodiment of the present invention to solve the above-mentioned another problem may be written, printed, or coated using the above-described fluorescent ink composition.

When the document is exposed to light having a wavelength in a certain range, fluorescence may be visible along the periphery of the written, printed, or coated strokes.

Specific details of other embodiments are included in the detailed description.

According to embodiments of the present invention, the fluorescent material spreads around the dots or strokes printed using ink, so that clear fluorescence can be confirmed regardless of the color of the dots and strokes. In other words, the present invention can achieve fluorescence expression that was considered impossible in conventional black color.

Therefore, there can be no restrictions on the basic color constituting the dot and stroke portion, and clear fluorescence can be confirmed even when, for example, black is used as the basic color. This can make it easier to prove the authenticity. Furthermore, ink compositions of various colors can be provided without limitations on base colors, and the field of application can be expanded.

Using this, it is possible to easily identify forged or altered documents, identify illegal copies, and identify the originals of works of art and other works of art.

Effects according to embodiments of the present invention are not limited to the contents exemplified above, and further various effects are included in the present specification.

Figures 1 and 2 are schematic diagrams showing the non-fluorescence state and the fluorescence expression state of documents written using a fluorescent ink composition according to an embodiment of the present invention, respectively.
Figure 3 is a schematic diagram showing the spread of the fluorescent ink composition of Figures 1 and 2.
Figures 4 to 6 are images written using the fluorescent ink compositions according to Preparation Examples 1 to 3, respectively.
Figure 7 shows images written using the fluorescent ink composition according to Preparation Example 4.
Figures 8 to 10 show images written using the fluorescent ink compositions according to Preparation Examples 5 to 7, respectively.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms, and only the embodiments serve to ensure that the disclosure of the present invention is complete, and those skilled in the art It is provided to fully inform the person of the scope of the invention, and the present invention is only defined by the scope of the claims. That is, various changes may be made to the embodiments presented by the present invention. The embodiments described below are not intended to limit the embodiments, but should be understood to include all changes, equivalents, and substitutes therefor.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings that can be commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless clearly specifically defined.

In this specification, 'pigment' refers to a pigment used by dispersing in a solvent, and 'dye' refers to a pigment used by dissolving in a solvent. The pigments and dyes may be collectively referred to as colorant.

Unless otherwise defined, value refers to the brightness according to CIE Lab's color space, where white is 100 and black is 0. If you divide CIE Lab's brightness by 10, it can almost match the brightness (V) according to the Munsell color system.

In this specification, the chemical symbol 'dpa' refers to dipicolinic acid.

In this specification, 'soluble' or 'solubility' refers to the property of dissolving 10 g or more in 1 L of a specific solvent. ‘Insoluble’ refers to the property of dissolving less than 0.1g in 1L of a specific solvent or substantially not dissolving at all.

In this specification, 'solvent' includes both polar solvents such as water (H ₂ O) and alcohol (-OH) and non-polar solvents such as benzene, hexane, and ether. It is used as a concept.

As used herein, 'and/or' includes each and every combination of one or more of the mentioned items. Additionally, the singular form also includes the plural form unless specifically stated in the phrase. As used herein, 'comprises' and/or 'comprising' do not exclude the presence or addition of one or more other components in addition to the mentioned components. The numerical range expressed using 'to' indicates a numerical range that includes the values written before and after it as the lower limit and upper limit, respectively. ‘About’ or ‘approximately’ means a value or numerical range within 20% of the value or numerical range stated thereafter.

Hereinafter, the present invention will be described in detail.

The ink composition according to an embodiment of the present invention includes a solvent, a first coloring material contained in the solvent, and a second coloring material contained in the solvent, and may further include animal protein.

The solvent may dissolve or disperse the first coloring material and the second coloring material. The type of solvent may be selected in consideration of the types of the first coloring material and the second coloring material, but may include a polar solvent or a non-polar solvent. Examples of the polar solvent include water (H ₂ O), alcohol, ethyl acetate, and dichloromethane, but the present invention is not limited thereto. Alcohol-based solvents may include methanol, ethanol, etc. Examples of the non-polar solvent include acetic acid, benzene, toluene, hexane, chloroform, or ether-based solvents such as diethyl ether and diisopropyl ether, but the present invention is not limited thereto. no.

The first coloring material may be a colored coloring material that provides the base color of the fluorescent ink composition according to the present invention. That is, when writing, printing, or coating using the fluorescent ink composition according to the present invention, the color may be expressed primarily by the first coloring material. More specifically, in a portion where a tool for writing using the fluorescent ink composition according to the present invention, such as a pen nib or brush, or a printing cartridge, or a coating member for coating, etc., directly contacts a base such as paper, the first coloring material Coloration may appear due to .

In an exemplary embodiment, the first colorant material may be made of a material that is substantially insoluble in the solvent, or at least poorly soluble. That is, the first colorant material may be insoluble in both polar solvents and non-polar solvents, or at least in the solvent used. For example, the first coloring material may have characteristics as a pigment. The first coloring material may remain dispersed in the solvent. The first coloring material exists in a solvent in the form of particles, and the average single particle size of the first coloring material may be in the range of about 40 nm to 80 nm. Additionally, the average particle size of the particle aggregate of the first coloring material may be in the range of about 400 nm to 1,000 nm. When the first coloring material is dispersed in a solvent, the first coloring material may be observed in the form of particle aggregates and may not substantially exist in a single particle state, but the present invention is not limited thereto.

The first color material may be a black colorant or a black colorant containing carbon black or carbon black particles (i.e., fine carbon particles). Carbon black, for example, carbon black particles, is insoluble in both polar solvents such as water and non-polar solvents, and may be dispersed in the solvent. As described above, in the case of conventional ink compositions containing fluorescent substances, it was impossible to use a bright color with high brightness as a base color or at least use a black color to express the fluorescent color.

However, as will be described later, the present invention can express excellent fluorescent color regardless of the color of the first coloring material by utilizing the difference in solubility of the first and second coloring materials in the solvent and the difference in spreading ability in the base using the same. . That is, even when the first coloring material contains black color, excellent fluorescence can be exhibited. Alternatively, the first coloring material may be made of a coloring material with a brightness (value) of 20 or less.

However, the present invention is not limited thereto, and if necessary, the first colorant may include an appropriately selected pigment material other than black color, such as a red colorant, a green colorant, a blue colorant, and/or a combination thereof.

The second coloring material may be a fluorescent material that provides the fluorescent color of the fluorescent ink composition according to the present invention, or a fluorescent coloring material. That is, when writing, printing, or coating using the fluorescent ink composition according to the present invention, in addition to the color expression by the first dye material described above, fluorescent color expression can be achieved by the second dye material under specific light conditions. there is. More specifically, fluorescence due to the second dye material may be expressed in a portion of the writing tool, printing cartridge, or coating member that is not in direct contact with the base.

In an exemplary embodiment, the second colorant material may be comprised of a material that is substantially soluble or soluble in a solvent. For example, the second coloring material may have dye properties. The second colorant material may remain dissolved in the solvent. In some embodiments, the second color material, even if not completely soluble in the solvent, has at least a higher solubility than the first color material, such as about 5 times more solubility, or about 10 times more solubility than the first color material. You can.

The second coloring material may optionally be soluble in a polar solvent such as water, or may be soluble in a non-polar organic solvent such as hexane and may exhibit fluorescence when irradiated with light of a specific wavelength. In addition, there is no particular limitation as long as it has the above characteristics and has excellent miscibility with the first coloring material, and does not cause a chemical reaction with the first coloring material.

For example, when using a polar solvent such as water as a solvent, the second colorant material may include M ₃ [L(dpa) ₃ ]. Here, M is an alkali metal element, and may be, for example, one of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), or cesium (Cs). Additionally, L is a lanthanoid and may be, for example, one of europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), or erbium (Er). dpa may be dipicolinic acid.

At this time, different fluorescence colors may appear as the type of lanthanide element changes. For example, when europium is used as a lanthanide element, a red-based fluorescent color can be displayed, and when terbium is used, a green-based fluorescent color can be displayed.

For another example, when using a non-polar organic solvent such as hexane or benzene as a solvent, the second coloring material may be porphyrazine, phthalocyanine, derivatives thereof, combinations thereof, and/or derivatives thereof. May include combinations.

For another example, the second coloring material may be a coumarin dye, a stilbene dye, a benzimidazole dye, a benzidine dye, or a naphthalimide dye. ) It may include aromatic compounds such as dyes. The materials may exhibit a blue-based or green-based fluorescent color. Depending on the type of the second coloring material, a polar solvent or a non-polar solvent can be used.

As described above, the second coloring material does not display color under normal visible light or cannot be recognized by humans. However, when irradiated with wavelengths of light other than visible light, such as infrared and ultraviolet rays, under certain conditions, they may fluoresce and be recognized. In a non-limiting example, the second dye material may exhibit strong fluorescence in an ultraviolet wavelength range of about 200 nm to 400 nm. More specifically, the second dye material may exhibit fluorescence for ultraviolet light having a single peak at about 240 nm to 260 nm or ultraviolet light having a single peak at about 350 nm to 380 nm.

The animal protein may include gelatin or chitosan. For example, the animal protein may be glue, derived from glue, or extracted from glue. The glue may refer to animal glue.

As a non-limiting example, the fluorescent ink composition according to the present invention can be manufactured using ink. Ink is generally prepared in the form of a bar by mixing and drying soot (carbon black) using animal glue, then grinding it on an inkstone and using it as a colloidal solution of carbon black. Ink is one of the traditionally used stationery items. In particular, the fluorescent ink composition according to the present invention can be used as a seal for art works, etc. to determine the authenticity of art works. Recently, interest in Korean culture is increasing around the world, and interest is growing in many previously unknown Korean works of art and literature. In particular, it is expected that the Korean feel can be further highlighted by applying watermarking technology to artworks using ink-based ink, which can give a traditional feel, like the present invention.

Therefore, when using traditional ink as described above to manufacture the fluorescent ink composition according to this embodiment, animal glue may be included. Animal glue can function as a binder for the first pigment materials. Also, although the present invention is not limited to any theory, it appears that animal glue also functions as a dispersant.

In some embodiments, the fluorescent ink composition according to the present invention may further include a dispersant for dispersing the first coloring material and an antifoaming agent to reduce foaming. Since known ingredients can be used for the dispersant and antifoaming agent, detailed descriptions are omitted.

Additionally, the fluorescent ink composition according to the present invention may not contain synthetic plastic components or preservatives.

As will be described later, according to experiments conducted by the inventor of the present invention, it was confirmed that fluorescence is not expressed in the case of an ink composition containing a polymer such as polyvinyl alcohol as an adhesive. Although the present invention is not limited to any theory, the synthetic polymer component inhibits the spread of the solvent from the base such as paper, and thus the spread of the second color material is limited, so as in the present invention, the first color material and the first color material are used. It appears that it is not possible to achieve fluorescence using differences in the spreading properties of the second dye material. In addition, in the case of synthetic polymers such as polyvinyl alcohol, they are reactive with the second coloring material, so the expression of fluorescence may rapidly decrease over time after coloring. In addition, preservatives are also reactive with the second coloring material and may reduce the expression of fluorescence over time after coloring. Examples of the preservative include formalin and the like.

The fluorescent ink composition according to an embodiment of the present invention may include about 3.0% to 12% by weight of the first coloring material, or about 7.0% to 9.0% by weight of the first coloring material, based on the total weight. Additionally, it may include about 0.01% to 1.0% by weight of a second coloring material and about 0.1% to 5.0% by weight of animal protein.

The solvent may be at least about 80% by weight, or at least about 83% by weight, or at least about 85% by weight. The upper limit for solvent content may be about 95% by weight, or about 93% by weight, or about 90% by weight.

If the first coloring material is contained less than the above range, it may be difficult to sufficiently develop the base color of the ink composition. On the other hand, if the first coloring material is contained in more than the above range, the color of the liquid state of the ink composition may become cloudy.

Additionally, if the second dye material is contained less than the above range, it may be difficult to develop clear fluorescence. On the other hand, if the second coloring material is contained more than the above range, manufacturing costs may increase, and ingredients harmful to the human body may be excessively used.

If the animal protein content is less than the above range, the color development may be lowered after writing or printing on a base such as paper, or may become blurred over time. Additionally, because the ink composition does not have the desired spreadability on a base such as paper, the area where the fluorescent color is expressed may not have a sufficient width. In other words, it may be difficult to achieve the effect unique to the present invention using the difference in spreading properties between the first coloring material and the second coloring material.

On the other hand, if the animal protein is contained in more than the above range, the overall viscosity of the ink composition increases, which not only reduces the ease of use, but also takes advantage of the difference in spreadability due to the viscosity of the solvent itself in which the second coloring material is dissolved. It may be difficult to achieve unique effects. For example, the width of the portion where the fluorescent color should be colored may be small, and/or the first coloring material and the second coloring material may not be sufficiently separated.

On the other hand, if the solvent is excessively contained, that is, if the above-mentioned first coloring material, second coloring material and animal protein are overall insufficiently contained, not only the above-mentioned problem occurs, but also the first coloring material and the second coloring material It may be difficult to demonstrate the unique effect of the present invention using differences in the spreading properties of the pigment material.

Hereinafter, a document using the fluorescent ink composition according to the present invention and its expression form will be described with reference to the attached drawings.

Figures 1 and 2 are schematic diagrams showing the non-fluorescence state and the fluorescence expression state of documents written using a fluorescent ink composition according to an embodiment of the present invention, respectively. Specifically, Figure 1 shows a state in which fluorescence is not visible under visible light conditions, and Figure 2 shows a state in which fluorescence is visible under light conditions of a specific wavelength, such as ultraviolet rays. Figure 3 is a schematic diagram showing the spread of the fluorescent ink composition of Figures 1 and 2.

Referring to Figures 1 to 3, a document written, printed, or coated using the fluorescent ink composition according to this embodiment can be prepared by coloring the ink composition on a base 10, such as paper, using a tool. Below, the case of writing the Korean character 'ga' using a brush will be described as an example, but of course, the present invention is not limited to this.

The fluorescent ink composition absorbed or adsorbed on the bristle portion of the brush may be transferred to the base 10 by contacting the base 10. At this time, the part where the brush comes into contact with the base 10 may be the first part 20.

The first part 20 may be a part where the author of the document actually intended to implement a stroke. That is, the first part 20 may substantially form a 'stroke'. In a state in which the fluorescence caused by the second dye material is not expressed, for example, under visible light, only the first part 20 may be visible to a person, and the second part 30 may not be visible, as shown in FIG. 1 .

The first part 20 may be a part in which the above-described first color material, that is, a pigment such as carbon black, is absorbed into the base 10 while dispersed in a solvent, or may be coated. In some embodiments, the first portion 20 may also contain a second coloring material in addition to the first coloring material, but the first coloring material has low brightness and absorbs visible light, thereby substantially adding the second coloring material. This may not be acknowledged.

On the other hand, the second part 30 may be a part formed by the brush not contacting the base 10, but at least a portion of the components of the fluorescent ink composition spread through the base 10.

The second part 30 is a part where the writer of the document does not touch the brush to create a stroke, but may be formed by spreading the second coloring material. As described above, the first coloring material is dispersed in a solvent, and its spreadability may be limited to a certain degree by animal proteins, etc. On the other hand, since the second coloring material is dissolved in the solvent, it can spread farther along with the solvent. In this way, the difference in solubility of the first coloring material and the second coloring material in the solvent can be used to cause a difference in the movement speed of the first coloring material and the second coloring material with respect to the base. Accordingly, under light of a specific wavelength, for example, under ultraviolet ray conditions, not only the first part 20 is visible as shown in FIG. 2, but also the second part 30 expressing a fluorescent color can also be visible to a person.

The second part 30 may be a part that substantially does not contain the above-described first coloring material and is absorbed into or coated with the base 10 in a state in which only dye such as the second coloring material is dissolved in a solvent.

As described above, the fluorescent ink composition according to the present invention has a significantly different solubility of the first coloring material and the second coloring material in the solvent, and accordingly, there is a difference in the spreading properties of the first coloring material and the second coloring material in the base. Alternatively, the difference in movement speed can be maximized. In other words, even when a writing, printing, or coating tool such as a brush contacts the first point P1, the first coloring material, etc. that is not dissolved in the solvent has a relatively small movement speed in the base 10, so the second It can only spread to point (P2). On the other hand, the second coloring material dissolved in the solvent can spread from the first point (P1) to the third point (P3) located further than the second point (P2) because the moving speed in the base 10 is relatively high. there is. Accordingly, it is possible to form a stroke portion substantially formed by the first colorant material, that is, a second portion 30 surrounding the first portion 20 .

Under normal visible light conditions, only the first part is visible, but under light conditions of a specific predetermined wavelength, the second part surrounding the first part may emit fluorescence together. Through this, the authenticity of the document can be determined.

Hereinafter, the present invention will be described in more detail with reference to experimental examples.

[Production Example 1]

The ink was ground on an inkstone from the Silla Jomuksa Temple to form ink, and Na ₃ [Eu(dpa) ₃ ] fluorescent material (red fluorescence) was dissolved in a small amount of water and mixed with the ink. Analysis of the prepared ink composition showed that carbon black had an average aggregate particle size of about 700 nm and was distributed at a level of about 400 nm to 1,200 nm. As a result of component analysis, it was found that the carbon black content was about 8.0wt%, the animal protein content was about 3.0wt%, and the fluorescent material content was about 0.7wt%. The content of water as a solvent was about 87wt% to 88wt%. Synthetic polymer plastics such as polyvinyl alcohol and chloroform were not detected.

Then, the fluorescent ink composition according to Preparation Example 1 was written on Korean paper with a brush, and the image under visible light is shown in Figure 4a, and the image under ultraviolet ray wavelength is shown in Figure 4b.

[Production Example 2]

An ink composition was prepared substantially in the same manner as Preparation Example 1, except that Na ₃ [Tb(dpa) ₃ ] fluorescent substance (green fluorescence) was used as the fluorescent substance. As a result of component analysis, synthetic polymer plastics such as polyvinyl alcohol and chloroform were not detected.

Then, the fluorescent ink composition according to Preparation Example 2 was written on Korean paper with a brush, and the image under visible light is shown in FIG. 5A, and the image under ultraviolet ray wavelength is shown in FIG. 5B.

[Production Example 3]

An ink composition was prepared substantially the same as Preparation Example 1, except that a stilbene-based diaminostilbene (DAS) fluorescence brightening agent was used as a fluorescent material. Diaminostilbene is soluble in water. As a result of component analysis, synthetic polymer plastics such as polyvinyl alcohol and chloroform were not detected.

Then, the fluorescent ink composition according to Preparation Example 3 was written on Korean paper with a brush, and the image under visible light is shown in Figure 6a, and the image under ultraviolet ray wavelength is shown in Figure 6b.

[Production Example 4]

It was prepared in the same manner as Preparation Example 3, but the amount of fluorescent material added and the mixing amount of solvent were adjusted. As a result of component analysis, it was found that the carbon black content was about 7.5 wt%, the animal protein content was about 6.0 wt%, and the fluorescent substance content was about 0.7 wt%.

Then, the fluorescent ink composition according to Preparation Example 4 was written on Korean paper with a brush, and the image under visible light is shown in Figure 7a, and the image under ultraviolet ray wavelength is shown in Figure 7b.

Referring to Figures 7a and 7b, it can be seen that the width of the fluorescent part, that is, the second part, is very thin, and the fluorescent color of the ink-colored part, that is, the first part, is also slightly visible. It was confirmed that the width of the second part varied depending on the animal protein content.

[Production Example 5]

Commercially available ink was purchased, and red fluorescent material was mixed with it. Then, water was further mixed and the carbon black content was adjusted to about 8.0 wt% and the fluorescent material content was adjusted to about 0.7 wt%. As a result of the component analysis, approximately 1.72 wt% of polyvinyl alcohol (PVA), which was presumed to be contained in the original ink, was detected, and animal glue was not included. The average particle size of the particulate matter (aggregate) is approximately 300 nm, and it is presumed that industrial carbon black was used.

Then, the fluorescent ink composition according to Preparation Example 5 was written on Korean paper with a brush, and the image under ultraviolet wavelength is shown in FIG. 8.

Referring to FIG. 8, it can be seen that almost no fluorescence was recognized even though the fluorescent material was contained at the same level as Preparation Example 1.

[Production Example 6]

Different types of commercial ink were purchased and the composition was adjusted as in Preparation Example 5. As a result of component analysis, approximately 1.13 wt% of polyvinyl alcohol, approximately 1.92 wt% of chloroform, and some ceramic components presumed to be contained in the original ink were detected. The average particle size of the particulate matter (aggregate) is approximately 300 nm, and it is presumed that industrial carbon black was used.

Then, the fluorescent ink composition according to Preparation Example 6 was written on Korean paper with a brush, and the image under ultraviolet wavelength is shown in FIG. 9.

Referring to FIG. 9, it can be seen that the width of the portion where the fluorescent color should be colored is small, or the first coloring material and the second coloring material are not sufficiently separated.

[Production Example 7]

It was prepared in the same manner as Preparation Example 1, but the amount of fluorescent material added and the mixing amount of solvent were adjusted. As a result of component analysis, it was found that the carbon black content was about 2.91wt%, the animal protein content was about 0.01wt%, and the fluorescent substance content was about 0.01wt%. The content of water as a solvent was about 96 wt% to 97 wt%. That is, the content of water, which is a solvent, was found to be significantly higher than that of Preparation Example 1. The fluorescent ink composition according to Preparation Example 7 was written on Korean paper with a brush, and the image under ultraviolet wavelength is shown in FIG. 10.

Referring to Figure 10, it can be seen that the fluorescent part spreads unevenly. This may be because the overall content of animal protein and other ingredients was too low.

Although the description has been made above with a focus on embodiments of the present invention, this is merely an example and does not limit the present invention, and those skilled in the art will be able to understand the present invention without departing from the essential characteristics of the embodiments of the present invention. It will be apparent that various modifications and applications not exemplified above are possible.

Therefore, the scope of the present invention should be understood to include changes, equivalents, or substitutes of the technical ideas exemplified above. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

Claims (12)

polar solvent;
As carbon black contained in the solvent, 3.0% by weight to 12% by weight of carbon black whose average particle size of aggregate particles is in the range of 400nm to 1,200nm;
At least one fluorescent coloring material contained in the solvent, 0.01% to 1.0% by weight of a coloring material that is soluble in the solvent or has a high solubility compared to the carbon black; and
An ink composition comprising 0.1% to 5.0% by weight of animal protein. According to paragraph 1,
An ink composition wherein the carbon black is a pigment material having a black color or a brightness of 20 or less. According to paragraph 1,
An ink composition wherein the average particle size of the single particles of carbon black is 40 nm to 80 nm. According to paragraph 1,
The animal protein is an ink composition comprising glue, a material derived from glue, or a material extracted from glue. According to paragraph 1,
An ink composition wherein the upper limit of the solvent content is 90% by weight. According to paragraph 1,
The fluorescent dye material includes M ₃ [L(dpa) ₃ ],
M is an alkali metal element, one of Li, Na, K, Rb or Cs,
An ink composition wherein L is a lanthanide element selected from Eu, Gd, Tb, Dy, or Er. According to paragraph 1,
The fluorescent dye material is,
An ink composition containing diaminostilbene. According to paragraph 1,
An ink composition containing no fluorescent pigment material and no reactive synthetic polymer. According to paragraph 1,
An ink composition containing no chloroform and polyvinyl alcohol. According to paragraph 1,
An ink composition in which fluorescence is visible along the periphery of a stroke when the ink composition is written, printed, or coated and exposed to light having a peak in a wavelength range of at least 200 nm to 400 nm. A document written, printed, or coated using the ink composition according to claim 1. According to clause 11,
A document in which fluorescence is visible along the periphery of written, printed, or coated strokes when exposed to light having a peak in the wavelength range of at least 200 nm to 400 nm.