KR102750549B1 - The security product for preventing forgery - Google Patents

Abstract

The present invention relates to a security product for preventing forgery and a method for detecting forgery using the same. According to one embodiment, the security product for preventing forgery has a characteristic of being labeled only by light of a specific wavelength, and thus can be utilized as a high-level security technology higher than the covert level.

Description

{The security product for preventing forgery}

The present disclosure relates to a security product for preventing forgery and a method for detecting forgery using the same.

Due to the development of counterfeiting technology, interest in anti-counterfeiting technology, which was previously limited to banknotes and ID cards, is expanding to all industries. In particular, research is actively being conducted on security above the covert level that hides anti-counterfeiting technology in order to utilize it in application fields that require a high level of security.

An example of covert level security technology is the introduction of a material that changes color only when a specific stimulus is received, and if a photothermal dye that absorbs light of a specific wavelength and generates heat is introduced into security technology based on a material that changes color due to heat, it can be utilized as a high-level security technology that is marked only by a specific wavelength.

Republic of Korea Patent Publication No. 10-2015-0017711 A (2015.02.17)

One aspect of the present invention is to provide a security system and security article for preventing forgery and tampering that can be utilized in security technology above the covert level.

A security article for preventing counterfeiting according to one aspect of the present invention may include a near-infrared absorbing photothermal dye and a donor acceptor Stenhouse adduct-based (DASA) thermochromic dye.

The above donor acceptor Stenhouse adduct system (DASA) compound may be represented by the following chemical formula 1.

[Chemical Formula 1]

(In the above chemical formula 1,

X ₁ and X ₂ are each independently O or NR is ₃ ,

X ₃ is a hydroxy group or a halogen;

R ₁ to R ₃ are each independently (C1-C7) alkyl or (C6-C12) aryl.

The above donor acceptor Stenhouse adduct system (DASA) compound may be represented by the following chemical formula 1-2.

[Chemical Formula 1-2]

(In the above chemical formula 1-2,

R ₁ to R ₃ are each independently (C1-C7) alkyl.)

The above near-infrared absorbing photothermal dye may be an organic photothermal dye including a diimmonium-based photothermal dye, a squarylium-based photothermal dye, a BODIPY-based photothermal dye, a cyanine-based photothermal dye, a polyaniline-based photothermal dye, a polydopamine-based photothermal dye, or a combination thereof.

The above diimmonium-based photothermal dye may be represented by the following chemical formula 2.

[Chemical formula 2]

(In the above chemical formula 2,

R ₅ to R ₈ are each independently (C1-C7)alkyl, (C1-C20)alkoxy, halogen, cyano, or nitro;

R ₁₁ to R ₁₈ are each independently (C1-C20)alkyl, (C3-C20)cycloalkyl, or (C6-C20)aryl;

a to d are each independently integers from 0 to 3;

X is an n-valent anion, where n is 1 or 2.)

The above diimmonium-based photothermal dye may be represented by the following chemical formula 2-2.

[Chemical Formula 2-2]

(In the above chemical formula 2-2,

X ^- is a halogen ion, tetraphenylborate ion, hexafluorophosphate ion (PF ₆ ^- ), hexafluoroantimonate ion (SbF ₆ ^- ), perchlorate ion (ClO ₄ ^- ), or , and x and y are each independently 0 or 1.)

The above diimmonium-based photothermal dye may be represented by the following chemical formula 2-3.

[Chemical Formula 2-3]

(In the above chemical formula 2-3,

x and y are each independently 0 or 1.)

The above squarylium-based photothermal dye may be represented by the following chemical formula 3.

[Chemical Formula 3]

(In the above chemical formula 3,

R ₂₁ and R ₂₂ are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, or (C6-C20)aryl;

R ₂₃ to R ₂₆ are each independently hydrogen, (C1-C20) alkyl, or (C6-C20) aryl; and R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ may be connected to each other to form a fused ring.

The above squarylium-based photothermal dye may be represented by the following chemical formula 3-1.

[Chemical Formula 3-1]

(In the above chemical formula 3-1,

R ₂₁ and R ₂₂ are each independently fluoro(C1-C7)alkyl.)

The above thermochromic dye and photothermal dye may be included in a weight ratio of 1:0.001 to 1.

The above security item may be a textile.

The above thermochromic dye may be included as one type or as a combination of thermochromic dyes having different colors after discoloration.

The above photothermal dye may be included as one type or as a combination of photothermal dyes having different maximum absorption wavelengths.

The above-mentioned tamper-evident security product according to one aspect may change color depending on the wavelength in the near-infrared range.

Another aspect of the present invention provides a method for detecting forgery and tampering, comprising: a step of irradiating the above-described forgery-preventing security article with light of a near-infrared wavelength; and a step of determining whether or not it is forged through a color change.

Security products for preventing forgery and tampering according to one aspect can be used as high-level security technology as they are marked only by light of a specific wavelength in the near-infrared range.

Specifically, a security article for preventing forgery according to one aspect is a combination of a photothermal dye that generates heat only by light of a specific wavelength in the near-infrared region and a thermochromic dye that changes color only above a specific temperature, so that when light of a specific wavelength in the near-infrared region is irradiated, heat is generated in the area irradiated with the light and the color can be changed by the generated heat. In addition, since the security contents cannot be identified before irradiating the article with light of a specific wavelength in the near-infrared region, it can be utilized as a high-level security technology.

In addition, the security article for preventing counterfeiting according to one aspect not only has excellent photothermal effects but can also implement distinct discoloration characteristics, and can be restored to its original color by irradiation with visible light after discoloration. In addition, the security article for preventing counterfeiting according to one aspect has low absorption of visible light wavelengths and is transparent, so it can be used in various industrial fields such as the clothing industry.

Figure 1 illustrates the visible light to near-infrared absorption spectrum of a diimmonium-based photothermal dye according to Manufacturing Example 2.
Figure 2 illustrates the visible light to near-infrared absorption spectrum of a squarylium-based photothermal dye according to Manufacturing Example 3.
Figure 3 illustrates the results of photothermal discoloration experiments of Example 1, Example 2, and Comparative Example 1.

Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As used herein, the singular form may be intended to include the plural form as well, unless the context clearly indicates otherwise.

Throughout this specification, references to a component as "comprises," "includes," "contains," or "has" a component, unless specifically stated to the contrary, do not exclude other components, but rather may include other components, and do not exclude additional unrecited elements, materials, or processes.

The numerical range used in this specification includes the lower and upper limits and all values within that range, the increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of the upper and lower limits of a numerical range defined in different shapes. Unless otherwise specifically defined herein, values outside the numerical range that may arise due to experimental error or rounding of values are also included in the defined numerical range.

Unless otherwise specifically defined herein, “about” may be considered a value within 30%, 25%, 20%, 15%, 10% or 5% of the stated value.

In this specification, “photothermal dye” means a compound that exhibits a photothermal effect that converts light energy into heat energy and generates heat when light is absorbed, and “thermochromic dye” means a compound that exhibits a color change according to a change in temperature.

Hereinafter, the present disclosure will be described in detail. However, this is merely exemplary and the present disclosure is not limited to the specific embodiments described as exemplary.

One aspect of the present invention provides a tamper-evident security article comprising a near-infrared absorbing photothermal dye and a donor acceptor Stenhouse adduct system (DASA) thermochromic dye.

Since the security product for preventing forgery and tampering according to one aspect includes the above-mentioned combination of components, it can be used as a high-level security technology because it can be marked only by near-infrared light of a specific wavelength.

The above donor-acceptor Stenhouse adducts (DASA) compounds are compounds having a structure in which an electron donor, an electron acceptor, and the donor and the acceptor are connected by a triene bridge, and have the characteristics of being able to change from colorless to colored by heat, and then changing from colored to colorless again by visible light. In addition, the color after discoloration can be controlled depending on the structure of the electron donor and electron acceptor.

The above electronic craftsman may be -NR ₁ R ₂ , and R ₁ and R ₂ may each independently be (C1-C7) alkyl, (C6-C12) aryl, or R ₁ and R ₂ may be connected to each other to form a ring, and -CH ₂ - of the alkyl of R ₁ and R ₂ may be substituted with -O-.

The above electron acceptor may be a (C3-C20) heterocycle containing -C(=O)- in the ring, or a (C3-C12) heterocycle, and the heterocycle may be further substituted with (C1-C7)alkyl or halo(C1-C7)alkyl. Specifically, the electron acceptor may be selected from the following structures.

In the above structure, X ₁ and X ₂ are each independently O or NR ₃ , and R ₃ can be (C1-C7) alkyl or (C6-C12) aryl.

Specifically, the donor acceptor Stenhouse adduct compound may be represented by the following chemical formula 1.

[Chemical Formula 1]

(In the above chemical formula 1,

X ₁ and X ₂ are each independently O or NR ₃ ,

X ₃ is a hydroxy group or a halogen;

R ₁ to R ₃ are each independently (C1-C7) alkyl or (C6-C12) aryl.

For example, R ₁ to R ₃ can each independently be (C1-C4) alkyl, and can be methyl or ethyl.

For example, R ₁ and R ₂ are the same as each other and can be (C1-C4) alkyl and can be methyl or ethyl.

The above donor acceptor Stenhouse adduct system (DASA) compound may be represented by the following chemical formula 1-1 or the following chemical formula 1-2.

[Chemical Formula 1-1]

[Chemical Formula 1-2]

(In the above chemical formulas 1-1 and 1-2,

R ₁ to R ₃ are each independently (C1-C7) alkyl;

X ₃ is a hydroxyl group or a halogen.)

The above donor acceptor Stenhouse adduct compound may be represented by the following chemical formula A, but is not limited thereto.

[Chemical Formula A]

The near-infrared absorbing photothermal dye according to one embodiment is not particularly limited as long as it generates heat by absorbing a wavelength in the near-infrared range, and may be, for example, an organic photothermal dye including a diimonium-based photothermal dye, a squarilum-based photothermal dye, a BODIPY-based photothermal dye, a cyanine-based photothermal dye, a polyaniline-based photothermal dye, a polydopamine-based photothermal dye, or a combination thereof.

The security article for preventing forgery according to one aspect may include one type of the photothermal dye, or a combination of photothermal dyes having different maximum absorption wavelengths, and when a combination of photothermal dyes having different absorption wavelengths is used, it can be utilized for higher security.

The above diimmonium-based photothermal dye can be represented, for example, by the following chemical formula 2.

[Chemical formula 2]

(In the above chemical formula 2,

R ₅ to R ₈ are each independently (C1-C7)alkyl, (C1-C20)alkoxy, halogen, cyano, or nitro;

R ₁₁ to R ₁₈ are each independently (C1-C20)alkyl, (C3-C20)cycloalkyl, or (C6-C20)aryl;

a to d are each independently integers from 0 to 3;

X is an n-valent anion, where n is 1 or 2.)

The above X is not particularly limited as long as it is a monovalent or divalent anion, but for example, it can be an anion of a monovalent or divalent organic acid or inorganic acid, and for example, it can be any one selected from organic carboxylic acid ions such as acetate ion, lactate ion, trifluoroacetate ion, propionate ion, benzoate ion, oxalate ion, succinate ion, and stearate ion; organic sulfonic acid ions such as methanesulfonate ion, toluene sulfonate ion, naphthalene monosulfonate ion, chlorobenzene sulfonate ion, nitrobenzene sulfonate ion, dodecylbenzene sulfonate ion, benzene sulfonate ion, ethane sulfonate ion, and trifluoromethane sulfonate ion; and organic borate ions such as tetraphenylborate ion and bisoxalateborate. Or fluoride ion, chloride ion, bromide ion, iodide ion; It may be any one selected from thiocyanate ion, hexafluoroantimonate ion, perchlorate ion, periodate ion, nitrate ion, tetrafluoroborate ion, hexafluorophosphate ion, molybdate ion, tungstate ion, titanate ion, vanadate ion, phosphate ion, etc., but is not limited thereto.

For example, n may be 1 and X may be a monovalent anion (X ^- ), and the diimmonium-based photothermal dye may be represented by the following chemical formula 2-1 or 2-2.

[Chemical Formula 2-1]

(In the above chemical formula 2-1,

R ₅ to R ₈ are each independently (C1-C7)alkyl, (C1-C20)alkoxy, halogen, cyano, or nitro;

R ₁₁ to R ₁₈ are each independently (C1-C20)alkyl, (C3-C20)cycloalkyl, or (C6-C20)aryl;

a to d are each independently integers from 0 to 3;

X ^- is a halogen ion, tetraphenylborate ion, hexafluorophosphate ion (PF ₆ ^- ), hexafluoroantimonate ion (SbF ₆ ^- ), perchlorate ion (ClO ₄ ^- ), or , and x and y are each independently 0 or 1.)

For example, R ₁₁ to R ₁₈ can each independently be (C1-C10)alkyl, (C3-C12)cycloalkyl, or (C6-C12)aryl, and specifically, R ₁₁ to R ₁₈ can each independently be (C1-C7)alkyl or (C1-C4)alkyl, and more specifically, can be methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, or t-butyl.

[Chemical Formula 2-2]

(In the above chemical formula 2-2,

X ^- is a halogen ion, tetraphenylborate ion, hexafluorophosphate ion (PF ₆ ^- ), hexafluoroantimonate ion (SbF ₆ ^- ), perchlorate ion (ClO ₄ ^- ), or , and x and y are each independently 0 or 1.)

The above diimmonium-based photothermal dye can be represented by the following chemical formula 2-3.

[Chemical Formula 2-3]

(In the above chemical formula 2-3,

x and y are each independently 0 or 1.)

More specifically, the above diimmonium-based photothermal dye can be represented by the following chemical formula B, but is not limited thereto.

[Chemical Formula B]

In the above chemical formula B, n-Bu means n-butyl.

The above squarylium-based photothermal dye can be represented by the following chemical formula 3.

[Chemical Formula 3]

(In the above chemical formula 3,

R ₂₁ and R ₂₂ are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, or (C6-C20)aryl;

R ₂₃ to R ₂₆ are each independently hydrogen, (C1-C20) alkyl, or (C6-C20) aryl; and R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ may be connected to each other to form a fused ring.

For example, the above R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ may be linked to form a ring, and L ₁ may be a single bond, O, S or (C1-C2)alkylene.

The above squarylium-based photothermal dye may be represented by the following chemical formula 3-1.

[Chemical Formula 3-1]

(In the above chemical formula 3-1,

R ₂₁ and R ₂₂ are each independently fluoro(C1-C7)alkyl.)

The above fluoro(C1-7) alkyl may be a perfluoro(C1-C7) alkyl group, and more specifically, may be, but is not limited to, -CF _{3 ,} -C ₂ F ₅ , -C ₃ F ₇ , -C ₄ F ₉ , C ₅ F ₁₁ .

More specifically, the above squarylium-based photothermal dye can be represented by the following chemical formula C, but is not limited thereto.

[Chemical Formula C]

A security product for preventing counterfeiting according to one aspect may contain the thermochromic dye and the photothermal dye in a weight ratio of 1:0.001 to 1.

A security product for preventing counterfeiting according to one aspect may include one type of the thermochromic dye, or may use a combination of two or three or more types of thermochromic dyes having different colors after discoloration, as necessary.

In addition, the security article for preventing forgery according to one aspect may include one type of the photothermal dye, or may use a combination of two or three or more types of photothermal dyes having different maximum absorption wavelengths, as needed. It is expected that in the future, if two or more types of photothermal dyes that absorb light of different wavelengths are used in combination, it can be utilized as a dual security technology in which different patterns appear depending on the wavelength.

The above-mentioned anti-counterfeiting security product is characterized by changing color according to wavelength in the near-infrared range, and after discoloration, can be restored to its original color according to wavelength in the visible light range.

In addition, the type of the above article may vary depending on the substrate, for example, a textile substrate may be used, and the anti-counterfeiting security article according to one embodiment may be an anti-counterfeiting security textile.

In addition, another aspect of the present invention provides a method for detecting forgery and tampering, including the steps of irradiating the above-described forgery-preventing security article with light of a near-infrared wavelength; and the step of determining whether it is forged or tampered with through a color change.

Hereinafter, the above-described implementation examples will be described in more detail through examples. However, the following examples are for the purpose of explanation only and do not limit the scope of the rights.

[Manufacturing Example 1] Manufacturing of thermochromic dye (compound A)

1,3-Dimethylbarbituric acid (1 eq) and 2-furaldehyde were added to purified water and stirred at room temperature (25°C) for two hours. The yellow solid mixture was filtered and washed several times with cold water. After extraction with MC/NaHSO ₃ , the organic layer was completely separated using MgSO ₄ , and the solvent was completely dried by distillation under reduced pressure to obtain 5-(furan-2-ylmethylene)-1,3-dimethylpyrimidin-2,4,6(1H,3H,5H)-trione (Compound A-1).

¹ H-NMR (300 MHz, CDCl ₃ ): δ (ppm) =8.65 (d, 1H), 8.45 (s, 1H), 7.86 (s, 1H), 6.81 - 6.69 (m, 1H), 3.41 (d) , 6H).

The compound A-1 (1 eq, 10 g) obtained above was dissolved in tetrahydrofuran (1 eq, 3.12 g), and then diethylamine (50 ml) was added. The mixture was stirred at room temperature for 30 minutes, cooled to 0 ℃, and stirred for another 30 minutes. Thereafter, the solvent was evaporated by distillation under reduced pressure, and the compound was obtained by precipitating with cold ether, and the obtained compound was freed of all solvents in a vacuum to obtain compound A.

¹ H-NMR (300 MHz, CDCl ₃ ): δ (ppm) =12.58 (d, 1H), 7.28 - 7.13 (m, 2H), 6.77 (d, 1H), 6.10 (t, 1H), 3.52 (p, 4H), 3.38 (d, 5H), 1.36 (dt, 7.2 Hz, 6H).

[Manufacturing Example 2] Manufacturing of diimmonium photothermal dye (compound B)

Tris(dibenzylideneacetone)dipalladium(0) 0.24 g (0.24 mmol) and tri-tertbutylphosphine 0.11 ml (0.37 mmol) were placed in a two-necked 100 ml flask and stirred for 10 minutes at room temperature using 20 ml toluene as a solvent. Then, 2.84 g (9.24 mmol) of 4-bromo-N,N-dibutylaniline was added and stirred for another 10 minutes at room temperature. Additionally, 0.2 g (1.85 mmol) of 1,4-aminobenzene and 2.3 g (21.6 mmol) of sodium tertbutoxide were added and stirred at 110 ℃ for 15 hours. The above reaction mass was cooled to room temperature, extracted with ethyl acetate, water was removed with sodium sulfate, filtered, and the organic solvent was completely distilled off using a reduced pressure distillation device. The concentrated compound was well dissolved in 50 ml of dimethylformamide (DMF), 150 ml of isopropyl alcohol was added, stirred at 0 ℃ for 1 hour, the recrystallized compound was filtered, and washed 2 to 3 times with methanol to obtain 1.4 g (82%) of a brown powder compound N,N,N',N'-tetrakis(p-dibutylaminophenyl)-p-phenylenediamine (Compound B-1).

In the above, 0.2 g (0.22 mmol) of compound B-1 and 0.12 g (0.54 mmol) of lithium bisoxalate borate were placed in a 2-necked 100 ml flask and stirred at 70°C for 4 hours using 10 ml of dichloromethane and 5 ml of ethanol as solvents. After that, 0.1 g (0.33 mmol) of potassium persulfate dissolved in 4 ml of water was added and stirred for another 2 hours. The mixture was extracted with water and dichloromethane, and after removing moisture with sodium sulfate and filtering, the organic solvent was completely distilled off using a reduced pressure distillation device. The concentrated compound was washed 2 to 3 times with normal hexane and dried to obtain 0.26 g (85%) of bisoxalate borate N,N,N',N'-tetrakis(p-dibutylaminophenyl)-p-phenylenedimonium (compound B).

¹ H-NMR (300MHz, CDCl ₃ ): δ (ppm) =6.90-6.71 (br d, 12H), 6.62-6.57 (br d, 8H), 3.28 (s, 16H), 1.55 (br m, 16H) , 1.36 (br m, 16H), 0.93 (br m, 24H).

[Manufacturing Example 3] Manufacturing of squarylium-based photothermal dye (compound C)

9-Fluorenone (10 mmol) and 1,8-diaminonaphthalene (10 mmol) were placed in a dried 100 ml 2-necked flask and dissolved in ethanol (40 ml). Acetic acid was slowly added to the mixture, heated, and stirred at 100°C for 24 hours. The mixture was cooled to room temperature (25°C) to terminate the reaction, filtered, and crystals were obtained from chloroform and hexane to obtain 1H,3H-spiro[fluorene-9,2-perimidine] (Compound C-1).

In the above, compound C-1 (0.936 mmol) and squaric acid (0.356 mmol) were placed in a 2-necked flask containing 100 ml and dissolved in butanol (10 ml) and toluene (10 ml). The mixture was stirred at 110°C for 24 hours while heating. After the solvent was completely distilled off to complete the reaction, the concentrated compound was dissolved in acetone and crystallized with ethanol to obtain 3-oxo-2-(1H,3H-spiro[fluorene-9,2-perimidin]-4-yl)-4-(1H,9H-spiro[fluorene-9,2-perimidin]-9-ylidene-3-ium)cyclobut-1-ten-1-oleate (Compound C-2).

The compound C-2 (1 eq) obtained above was added to 40 ml of anhydrous ethyl acetate (EA) and completely dissolved at room temperature, and the reaction solution was cooled to -10 °C. After slowly adding triethylamine (1 eq), the mixture was stirred for 10 minutes, and trifluoroacetic anhydride (1.5 eq) dissolved in 5 ml of EA was slowly added to the mixture while being careful not to increase the temperature, and the mixture was stirred at -10 °C for 2 hours. The temperature was slowly increased to room temperature, and the reaction was completed after 12 hours of stirring at room temperature. The completed reaction mixture was extracted several times with EA and brine, and purified through a column with MC/MeOH (1:10) to obtain compound C.

¹ H-NMR (300 MHz, DMSO): δ 11.21 (s, 1H), 11.00 (s, 1H), 7.75 (m, 0.9 Hz, 4H), 7.38 (m, 1.3 Hz, 4H), 7.33 - 7.22 (m , 8H), 7.22 - 7.11 (m, 8H), 6.63 (m, 4H).

[Example 1]

Step 1

The thermochromic dye (compound A) obtained in the above Manufacturing Example 1 was dissolved in distilled water at a concentration of 0.5 mg/mL to prepare a solution, and cotton yarn (100% cotton / 20 counts, 4 ply / manufactured by Woodzen Co., Ltd., product number 1029178) was completely immersed in the solution for 3 hours, then taken out and dried to prepare a fiber dyed with the thermochromic dye.

Step 2

The diimmonium-based photothermal dye (compound B) obtained in the abovementioned Manufacturing Example 2 was dissolved in tetrahydrofuran (THF) at 0.25 mg/ml to prepare a photothermal dye solution, and then a fiber dyed with the thermochromic dye was briefly immersed in it, then taken out and dried to prepare a security fiber for preventing counterfeiting of Example 1.

[Example 2]

In step 2 of the above Example 1, the same procedure was performed, except that instead of the diimmonium-based photothermal dye, a photothermal dye solution containing 1 mg/mL of the squarylium-based photothermal dye (compound C) obtained in the above Preparation Example 3 was used in tetrahydrofuran (THF).

[Comparative Example 1]

In the above Example 1, only step 1 was performed to obtain a fiber dyed with a thermochromic dye.

[Comparative Example 2]

The diimmonium-based photothermal dye (compound B) obtained in the above manufacturing example 2 was dissolved in tetrahydrofuran (THF) at 0.25 mg/ml to prepare a photothermal dye solution, and then cotton yarn was briefly immersed in the solution, taken out, and dried to obtain a fiber dyed with the diimmonium-based photothermal dye.

[Comparative Example 3]

The squarylium-based photothermal dye (compound C) obtained in the above manufacturing example 3 was dissolved in tetrahydrofuran (THF) at 1 mg/ml to prepare a photothermal dye solution, and then cotton yarn was briefly immersed in the solution, taken out, and dried to obtain a fiber dyed with the squarylium-based photothermal dye.

<Evaluation example>

Evaluation 1. Maximum absorption wavelength (λ) of photothermal dye _max )

The maximum absorption wavelengths of the photothermal dyes obtained in Manufacturing Examples 2 and 3 were measured using a UV-Vis-NIR spectrometer (JASCO V-770). The maximum absorption wavelength of the diimmonium-based photothermal dye of Manufacturing Example 2 was confirmed to be about 1100 nm (Fig. 1), and the maximum absorption wavelength of the squarylium-based photothermal dye of Manufacturing Example 3 was confirmed to be about 800 nm (Fig. 2).

Evaluation 2. Photothermochromic experiment

The fibers obtained in the above examples and comparative examples were placed on paper without lifting, and a photothermal discoloration experiment was performed. The photothermal discoloration experiment was performed using a near-infrared laser (NIR laser) having a wavelength of 808 nm and 1064 nm, at a power of 1 W, a diameter of 8 mm, and a height of 15 cm for 180 seconds, and the temperature was observed using a thermal imaging camera, and the color change was observed with the naked eye. The results are shown in Table 1 and Fig. 3 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Maximum temperature 808nm 37.2 ℃ 54.57 ℃ 28.63 ℃ 37.25 ℃ 54.86 ℃ 1064nm 63.5 ℃ 32.00 ℃ 27.1 ℃ 63.2 ℃ 31.84 ℃ Color change Before light exposure Colorless Colorless Colorless Colorless Colorless 808nm - Pink - - - 1064nm Pink - - - -

Referring to Table 1 and FIG. 3, the fibers of Example 1 and Comparative Example 2, which include a diimmonium-based photothermal dye having a maximum absorption wavelength close to 1064 nm, showed an increase in the temperature of the fiber surface due to the photothermal effect only when a 1064 nm NIR laser was used, and when irradiated with an 808 nm NIR laser, there was no significant difference from the fiber of Comparative Example 1 that did not include the photothermal dye, and the discoloration temperature of the thermochromic dye was not reached. In addition, it can be seen that the fibers of Example 2 and Comparative Example 3, which include a squarylium-based photothermal dye having a maximum absorption wavelength close to 808 nm, showed an increase in the temperature of the fiber surface due to the photothermal effect only when an 808 nm NIR laser was used.

In addition, it was confirmed that the security fiber of Example 1 including a thermochromic dye and a diimmonium-based photothermal dye selectively showed a color change only when irradiated with a 1,064 nm NIR laser, and the security fiber of Example 2 including a thermochromic dye and a squarylium-based photothermal dye selectively showed a color change only when irradiated with an 808 nm NIR laser. On the other hand, in the case of the fiber of Comparative Example 1 that was not dyed with a photothermal dye, there was no color change regardless of the irradiation with a NIR laser of any wavelength, and it could be seen that the fibers of Comparative Examples 2 and 3 that did not include a thermochromic dye showed no color change although the temperature increased by light irradiation.

In addition, it was confirmed that the security fibers of Examples 1 and 2 returned to their original color when irradiated with visible light after discoloration.

That is, the security fiber according to the present invention can secure a high security level higher than the covert level by selectively exhibiting color change only by a specific wavelength. In addition, it is expected that in the future, if two or more photothermal dyes that selectively absorb light of different wavelengths are used in combination, it can be utilized as a dual security technology in which different patterns appear depending on the wavelength.

Although the above implementation example has been described in detail through examples and experimental examples, the scope of the implementation example is not limited to specific examples, and should be interpreted according to the appended patent claims.

Claims (15)

A security article for preventing counterfeiting, comprising a near-infrared absorbing photothermal dye and a donor acceptor Stenhouse adduct-based (DASA) thermochromic dye,
The above donor-acceptor Stenhouse adduct thermochromic dye is a compound having a structure in which an electron donor, an electron acceptor, and the donor and the acceptor are linked by a triene bridge, and can be changed from colorless to colored by heat, and can be changed from colored to colorless again by visible light, a security article for preventing counterfeiting. In the first paragraph,
A security article for preventing counterfeiting, wherein the donor acceptor Stenhouse adduct system (DASA) compound is represented by the following chemical formula 1.
[Chemical Formula 1]

In the above chemical formula 1,
X ₁ and X ₂ are each independently O or NR is ₃ ,
X ₃ is a hydroxy group or a halogen;
R ₁ to R ₃ are each independently (C1-C7) alkyl or (C6-C12) aryl. In the first paragraph,
A security article for preventing counterfeiting, wherein the donor acceptor Stenhouse adduct system (DASA) compound is represented by the following chemical formula 1-2.
[Chemical Formula 1-2]

In the above chemical formula 1-2,
R ₁ to R ₃ are each independently (C1-C7) alkyl. In the first paragraph,
A security article for preventing counterfeiting, wherein the near-infrared absorbing photothermal dye is an organic photothermal dye including a diimmonium-based photothermal dye, a squarylium-based photothermal dye, a BODIPY-based photothermal dye, a cyanine-based photothermal dye, a polyaniline-based photothermal dye, a polydopamine-based photothermal dye, or a combination thereof. In paragraph 4,
A security product for preventing counterfeiting, wherein the above diimmonium-based photothermal dye is represented by the following chemical formula 2.
[Chemical formula 2]

In the above chemical formula 2,
R ₅ to R ₈ are each independently (C1-C7)alkyl, (C1-C20)alkoxy, halogen, cyano, or nitro;
R ₁₁ to R ₁₈ are each independently (C1-C20)alkyl, (C3-C20)cycloalkyl, or (C6-C20)aryl;
a to d are each independently integers from 0 to 3;
X is an n-valent anion, where n is 1 or 2. In paragraph 4,
A security product for preventing counterfeiting, wherein the above diimmonium-based photothermal dye is represented by the following chemical formula 2-2.
[Chemical Formula 2-2]

In the above chemical formula 2-2,
X ^- is a halogen ion, tetraphenylborate ion, hexafluorophosphate ion (PF ₆ ^- ), hexafluoroantimonate ion (SbF ₆ ^- ), perchlorate ion (ClO ₄ ^- ), or , and x and y are each independently 0 or 1. In paragraph 4,
A security product for preventing counterfeiting, wherein the above diimmonium-based photothermal dye is represented by the following chemical formula 2-3.
[Chemical Formula 2-3]

In the above chemical formula 2-3,
x and y are each independently 0 or 1. In paragraph 4,
A security product for preventing counterfeiting, wherein the above squarylium-based photothermal dye is represented by the following chemical formula 3.
[Chemical Formula 3]

In the above chemical formula 3,
R ₂₁ and R ₂₂ are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, or (C6-C20)aryl;
R ₂₃ to R ₂₆ are each independently hydrogen, (C1-C20)alkyl, or (C6-C20)aryl; R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ may be linked to each other to form a fused ring. In paragraph 4,
A security product for preventing counterfeiting, wherein the above squarylium-based photothermal dye is represented by the following chemical formula 3-1.
[Chemical Formula 3-1]

In the above chemical formula 3-1,
R ₂₁ and R ₂₂ are each independently fluoro(C1-C7)alkyl. In the first paragraph,
A security article for preventing counterfeiting, wherein the thermochromic dye and the photothermal dye are included in a weight ratio of 1:0.001 to 1. In the first paragraph,
The above security item is a textile security item for preventing forgery and tampering. In the first paragraph,
A security product for preventing counterfeiting, wherein the thermochromic dye is one type or a combination of thermochromic dyes whose colors after discoloration are different from each other. In the first paragraph,
A security product for preventing counterfeiting, wherein the photothermal dye is one type or a combination of photothermal dyes having different maximum absorption wavelengths. In the first paragraph,
The above-mentioned anti-counterfeiting security product is a anti-counterfeiting security product whose color changes depending on the wavelength in the near-infrared range. A method for detecting counterfeiting, comprising: a step of irradiating light of a near-infrared wavelength to a security product for preventing counterfeiting selected from any one of claims 1 to 14; and a step of determining whether the product is counterfeit or not through a change in color.