JP3265034B2 - Security ink composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a security ink for preventing forgery of prepaid cards, gift certificates, securities and the like. More specifically, the present invention relates to a security ink containing a phthalocyanine compound as a near-infrared absorbing agent and an acrylic resin.

[0002]

2. Description of the Related Art There are several methods for preventing counterfeiting of prepaid cards and the like.
There is a method using security ink that cannot be read by a normal visible light sensor. In this case, a near-infrared absorbing agent is usually used. As a specific method, a security ink containing a near-infrared absorbing agent and a binder resin is printed on the surface of the prepaid card. As the near-infrared absorbing agent, a dye having an absorption wavelength at 700 to 1100 nm is used. As the binder resin, those usually used for coating a film or paper may be used. For example, urethane-based, epoxy-based, phenol-based, and polyester-based resins are used. Here, since the thickness of 3 μ or more is sensed by touch, the print thickness is preferably 3 μ or less. When a prepaid card printed using the security ink produced by the above method is irradiated with near-infrared rays (700 to 1100 nm), light having a wavelength in that region is absorbed, so that the card can be read. That is, the recording surface is irradiated with an infrared laser, and the difference in reflection between a recorded portion and a non-recorded portion at a specific wavelength is read. Utilization of this principle makes it possible to determine authenticity.

[0003] Security ink compositions containing these near infrared absorbers are required to have various physical and chemical properties as described below. (1) The near infrared absorbing agent is completely dissolved in the security ink composition. In the case of poor dissolution, if the pigment particles are large, they may be sensed by touch. (2) The near-infrared absorbing agent has a large molar extinction coefficient. If it is small, it is necessary to add a large amount to the ink, and the printing thickness may exceed 3μ. (3) The security ink composition is 700 to 1100
It is necessary to have an absorption band in the wavelength range of nm. (4) The security ink composition is 400 to 700 n
The absorption in the visible region of m is small. If the absorption in the visible region is large, the ink will be colored and will no longer serve as a security ink. (5) The heat and light resistance of the security ink composition is good. In the case of a defect, the absorption of the wavelength in the near-infrared region becomes incomplete due to a change over time, and a reading error may occur. None of the known security ink compositions satisfying all these points has been reported.

Japanese Patent Application Laid-Open No. Hei 4-320466 proposes a security ink containing a phthalocyanine compound having an o-aminophenylthioether group in a cyclohexanone-based solvent. Since the absorption in the visible region of 700 nm is relatively large, coloring is conspicuous and is insufficient for use as a security ink. Also,
JP-A-3-62878 describes a phthalocyanine compound having a large absorption in a near-infrared region, particularly in a semiconductor laser oscillation wavelength region (760 to 830 nm).
However, there is no description of a method of using the phthalocyanine compound to form an ink layer on paper or resin that does not fall off even when touched by hand and has excellent light resistance.

[0005]

An object of the present invention is to provide a security ink composition using a phthalocyanine compound.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a certain phthalocyanine
The present inventors have found that the problem of coloring and light fastness can be solved by preparing a security ink composition by combining an anine compound with an acrylic resin binder, and completed the present invention. That is, the present invention relates to a security ink composition containing a phthalocyanine compound represented by the general formula (I) (Formula 2) and an acrylic resin. Further, the present invention relates to the security ink composition, wherein the acrylic resin is a polyalkyl methacrylate.

[0007]

Embedded image [In the formula (I), A ^{1 to} A ⁸ are each independently substituted or unsubstituted.
An alkoxy group of conversion, the B ¹ .about.B ⁸ are each independently, C
Represents a halogen atom, a substituted or unsubstituted arylthio group.
M represents a divalent metal atom, a trivalent or tetravalent substituted metal atom, or an oxymetal. ]

[0008] The security ink composition of the present invention has low coloring, has absorption between 700 and 1100 nm,
Further, it is a security ink composition having excellent heat resistance and light resistance, and the near-infrared absorbing agent used in the present invention is a phthalocyanine compound represented by the general formula (I).

In the phthalocyanine represented by the formula (I), A
¹ Examples of the substituted or unsubstituted alkoxy group represented by to A ^8, a methoxy group, an ethoxy group, n- propyl group, iso- propyl group, n- butyloxy, iso-
Butyloxy group, sec-butyloxy group, t-butyloxy group, n-pentyloxy group, iso-pentyloxy group, neo-
Pentyloxy group, 1,2-dimethyl-propyloxy group,
n-hexyloxy group, cyclo-hexyloxy group, 1,3-dimethyl-butyloxy group, 1-iso-propylpropyloxy group, 1,2-dimethylbutyloxy group, n-heptyloxy group, 1,4-dimethyl Pentyloxy group, 2-methyl-1-iso-
Propylpropyloxy group, 1-ethyl-3-methylbutyloxy group, n-octyloxy group, 2-ethylhexyloxy group, 3-methyl-1-iso-propylbutyloxy group, 2-methyl-1-iso-propyl C 1-2 groups such as oxy group, 1-t-butyl-2-methylpropyloxy group, n-nonyloxy group, etc.
0 linear or branched alkoxy, methoxymethoxy, methoxyethoxy, ethoxyethoxy, propoxyethoxy, butoxyethoxy, γ-methoxypropyloxy, γ-ethoxypropyloxy, methoxyethoxyethoxy, ethoxy Alkoxyalkoxy groups such as ethoxyethoxy group, dimethoxymethoxy group, diethoxymethoxy group, dimethoxyethoxy group, diethoxyethoxy group, etc., methoxyethoxyethoxy group, ethoxyethoxyethoxy group, butyloxyethoxyethoxy group, etc., alkoxy Alkoxyalkoxyalkoxy group, chloromethoxy group, 2,2,2-trichloroethoxy group, trifluoromethoxy group, 2,2,2-trifluoroethoxy group, 1,1,1,3,3,3,-
Examples include a halogenated alkoxy group such as a hexafluoro-2-propyloxy group, an alkylaminoalkoxy group such as a dimethylaminoethoxy group and a diethylaminoethoxy group, and a dialkylaminoalkoxy group.

Examples of the substituted or unsubstituted arylthio groups represented by B ^{1 to} B ⁸ include a phenylthio group, a naphthylthio group and an alkylphenylthio group.

Examples of halogen include fluorine, chlorine, bromine and iodine.

Examples of the divalent metal represented by M include Cu (II), Zn (II), Co (II) and Ni (I
I), Ru (II), Rh (II), Pd (II), Pt (I
I), Mn (II), Mg (II), Ti (II), Be (I
I), Ca (II), Ba (II), Cd (II), Hg (I
I), Pb (II), Sn (II) and the like. Examples of monosubstituted trivalent metals include Al-Cl, Al-Br,
Al-F, Al-I, Ga-Cl, Ga-F, Ga-
I, Ga-Br, In-Cl, In-Br, In-I,
In-F, Tl-Cl, Tl-Br, Tl-I, Tl-
_{F, Al-C 6 H 5} , Al-C 6 H 4 (CH 3), In
_{-C 6 H 5, In-C} 6 H 4 (CH 3), In-C 6 H
₅ , Mn (OH), Mn (OC ₆ H ₅ ), Mn [OSi
(CH _{3) 3],} Fe-Cl, include Ru-Cl, etc.. Examples of disubstituted tetravalent metals include CrCl ₂ , Si
Cl ₂ , SiBr ₂ , SiF ₂ , SiI ₂ , ZrC
l ₂ , GeCl ₂ , GeBr ₂ , GeI ₂ , GeF ₂ ,
SnCl ₂ , SnBr ₂ , SnF ₂ , TiCl ₂ , Ti
Br ₂ , TiF ₂ , Si (OH) ₂ , Ge (OH) ₂ ,
Zr (OH) ₂ , Mn (OH) ₂ , Sn (OH) ₂ , T
iR ₂ , CrR ₂ , SiR ₂ , SnR ₂ , GeR ₂ [R
Represents an alkyl group, a phenyl group, a naphthyl group, and derivatives thereof], Si (OR ′) ₂ , Sn (OR ′) ₂ ,
Ge (OR ') ₂ , Ti (OR') ₂ , Cr (OR ')
₂ [R ′ represents an alkyl group, a phenyl group, a naphthyl group, a trialkylsilyl group, a dialkylalkoxysilyl group and a derivative thereof], Sn (SR ″) ₂ , Ge (S
R ″) ₂ (R ″ represents an alkyl group, a phenyl group, a naphthyl group, and derivatives thereof), etc. Examples of the oxymetal include VO, MnO, and TiO.

Of these, particularly preferred is phthalocyanine having an absorption maximum around 760 to 830 nm, which is a semiconductor laser oscillation wavelength region, and a binder resin,
Particularly good mutual solubility with the acrylic resin, a easy phthalocyanine ink production, in formula (I), A ¹ ~
A ⁸ is a substituted or unsubstituted alkoxy group having 2 to 10 carbon atoms, B ^{1 to} B ⁸ are arylthio groups such as a phenylthio group, a naphthylthio group, a methylphenylthio group having 6 to 12 carbon atoms, and M is Cu, Ni, Co, Fe, Pd, V
O and TiO are preferred.

Usually, a security ink can be obtained by incorporating a near-infrared absorbing agent into a binder resin. Specifically, a security ink is produced by dissolving a near-infrared absorbing agent in a solvent and adding the binder resin thereto. . The amount of the phthalocyanine compound used as the near-infrared absorber in the present invention is not limited to a uniform one, since it is determined according to the absorption amount in the desired near-infrared region, or the thickness of the coating. It is preferable to use it in the range of 0.1 to 10 (% by weight) based on the acrylic resin as the binder.

Examples of the acrylic resin as a binder include ketones and esters which are general-purpose solvents for inks.
Resins soluble in cellsolves, aromatic hydrocarbons and the like are used. Examples thereof include polyalkyl acrylates such as polymethyl acrylate, polyethyl acrylate, and polybutyl acrylate, and polyalkyl methacrylates such as polymethyl methacrylate, polyethyl methacrylate, and polybutyl methacrylate. Among them, particularly preferred are polyalkyl methacrylates such as polymethyl methacrylate and polyethyl methacrylate.

Examples of the solvent include aliphatic hydrocarbons such as n-hexane and n-heptane, aromatic hydrocarbons such as toluene and xylene, methyl alcohol, ethyl alcohol and propyl alcohol which are usually used in gravure inks and screen inks. , Butyl alcohol, cyclohexyl alcohol, alcohols such as 2-methylcyclohexyl alcohol, methyl acetate, ethyl acetate, propyl acetate,
Esters such as butyl acetate, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIB
K), ketones such as cyclohexanone and methylcyclohexanone, glycols such as ethylene glycol and propylene glycol, glycol ethers such as cellosolve, methylcellosolve and butylcellosolve, cellosolve acetate, butylcellosolve acetate, carbitol acetate and the like Can be used, but esters or ketones are used alone or a mixed solvent containing them is preferable from the problem of solubility of the acrylic resin. The amount of the solvent to be used with respect to the acrylic resin can be appropriately selected depending on the required viscosity of the ink, but it is usually 1 to 100 times (weight) times.

In the security ink of the present invention, if necessary, a polymerization initiator, a plasticizer, an antioxidant, an ultraviolet absorber, a thickener, a wax, etc. which are added to ordinary gravure inks, screen inks, etc. Can also be added. Based on the above embodiments, the security ink composition of the present invention containing a phthalocyanine compound and an acrylic resin can solve all of the above-mentioned required properties (1) to (5), so that there is no reading error. An excellent prepaid card can be provided which is not sensed by touch, which is extremely valuable in practical use.

[0018]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited by this. The phthalocyanine compounds represented by the formulas (II) to (V) shown in the examples are obtained by simplifying the structure represented by the formula (I) in the text. Example 1 5 g of polymethyl methacrylate (PMMA) pellets (Delpet 80N manufactured by Asahi Kasei Corporation) and the following formula (II)
100 mg of copper phthalocyanine represented by the following formula (3) was dissolved in 30 ml of ethyl acetate to prepare a security ink composition. After coating this security ink composition on PET synthetic paper (Toray Co., Ltd. Lumilar white type, 188 μ thickness) using a coil bar (No. 12),
The solvent was removed by drying at room temperature for 1 hour. The coating surface was measured for total reflection at an incident angle of 45 ° using a spectrophotometer UV2200 manufactured by Shimadzu Corporation (magnesium oxide standard). The reflectance of visible light was calculated according to JIS-R-3106 to be 81%. The minimum reflectance in the near infrared region was 11% (760 nm). A light resistance test was performed by irradiating the coated surface of the synthetic paper with a carbon arc lamp at 63 ° C. for 24 hours. After the test,
When the reflectance was measured in the same manner, the visible light reflectance was 81% and the minimum reflectance was 13% (760 nm). The change in reflectance before and after the test was small, and the light resistance was good.

[0019]

Embedded image

Example 2 Instead of phthalocyanine (II) in Example 1, the following formula (I)
II) Except for using the copper phthalocyanine represented by (Chem. 4), the same operation as in Example 1 was performed to prepare a security ink, and coating was performed on PET synthetic paper. When the reflectance was measured in the same manner, the visible light reflectance was 82%,
The minimum reflectance was 15% (798 nm). When the reflectance was measured by performing the same 24-hour light resistance test as in Example 1, the visible light reflectance was 82%, and the minimum reflectance was 17% (798n).
m), the change in reflectance before and after the test was small, and the light resistance was good.

[0021]

Embedded image

Example 3 Acrylic resin (Uban 20S manufactured by Mitsui Toatsu Chemicals, Inc.)
A security ink was prepared by dissolving 5 g of E-60 and Almatex 748-5M manufactured by the company in a ratio of 3: 7) and 100 mg of copper phthalocyanine represented by the following formula (IV) (formula 5) in 30 ml. . Coating was performed on PET synthetic paper in the same manner as in Example 1. When the reflectance was measured in the same manner, the visible light reflectance was 85% and the minimum reflectance was 12%.
(740 nm). When the reflectance was measured by performing the same 24-hour light resistance test as in Example 1, the visible light reflectance was 85% and the minimum reflectance was 13% (740 nm). The change in reflectance before and after the test was small, and the light resistance was high. The properties were good.

[0023]

Embedded image

Comparative Example 1 The polymethyl methacrylate (PM
MA) Instead of using pellets, saturated polyester resin pellets (Toyobo Co., Ltd. Byron 200) were used.
The same operation as in Example 1 was performed to prepare a security ink, and coating was performed on PET synthetic paper. When the reflectance was measured in the same manner, the visible light reflectance was 80% and the minimum reflectance was 10% (778 nm). When the reflectance was measured by performing the same 24-hour light resistance test as in Example 1, the visible light reflectance was 82%, and the minimum reflectance was 60% (778 n).
m), the reflectance was large before and after the test, and the light resistance was insufficient.

Comparative Example 2 Example 1 was repeated except that phthalocyanine (II) of Example 1 was replaced by 200 mg of copper phthalocyanine in which an amino group represented by the following formula (V) was directly bonded to the phthalocyanine skeleton. A security ink was prepared by performing the same operations as described above, and coating was performed on PET synthetic paper. When the reflectance was measured in the same manner, the visible light reflectance was 65%,
The minimum reflectance was 18% (990 nm). It was insufficient as a security ink because of low visible light reflectance and large coloring.

[0026]

Embedded image

[0027]

The phthalocyanine compound used in the present invention has a high solubility in an organic solvent and a resin binder, and the security ink can be easily prepared. Also, due to the high molar extinction coefficient, when recording on paper or resin, the difference between the reflectance of the recorded part and the non-recorded part in a specific near-infrared region is remarkable with a small amount of use, which may cause a reading error. Is small. Furthermore, as is clear from the examples and comparative examples, when a saturated polyester was used as a binder, the light resistance was remarkably reduced. However, a security ink having high light resistance could be obtained by using an acrylic binder. . The phthalocyanine compound used in the present invention has a low coloration, the transparency of the ink is high, and when coated on white paper, the minimum reflectance in the near infrared region is 10 to 10.
The visible light reflectance was 80% or more even when reduced to about 20%. As a result, it is possible to provide an excellent prepaid card which has no reading error and is not visually perceived, and is extremely valuable in practical use.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-138382 (JP, A) JP-A-3-62878 (JP, A) JP-A-4-39361 (JP, A) JP-A-4- 292671 (JP, A) JP-A-4-320466 (JP, A) JP-A-62-177076 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11 / 20 B41M 3/14 C09B 47/00-47/32 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. Phthalo represented by the general formula (I) (Formula 1)
Cyanine compound [In the formula (I), A ^{1 to} A ⁸ are each independently substituted or unsubstituted.
An alkoxy group of conversion, the B ¹ .about.B ⁸ are each independently, C
Represents a halogen atom, a substituted or unsubstituted arylthio group.
M represents a divalent metal atom, a trivalent or tetravalent substituted metal atom, or an oxymetal. ] And an acrylic resin. 2. The security ink composition according to claim 1, wherein the acrylic resin is a polyalkyl methacrylate.