JP3317033B2 - Infrared transmitting 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 an infrared transmitting ink composition used for printing confidential information which can be read by infrared rays, and in particular, has a high light resistance, has a light absorption in a visible region, and has an infrared region. The present invention relates to an infrared transmitting ink composition having no absorption.

[0002]

2. Description of the Related Art Conventionally, machine-readable code marks such as bar codes and OCR characters have been used as means for reading information described in securities such as stock certificates, bonds, checks, gift certificates, lottery tickets, commuter passes and the like. Often provided, the substrate surface that normally reflects light in the near infrared region (for example,
A code mark is formed on a paper, a plastic, or the like, or a base material which is easily processed to reflect light, using black ink containing carbon black or the like that absorbs light in a near-infrared region. As a forgery preventing means in this case, a concealing layer having no absorption in the infrared region is formed on the code mark, or a black ink which shows the same black color as carbon black visually but does not absorb in the infrared region is used. In some cases, a dummy pattern is formed by reading a code mark based on the presence or absence of reading in the infrared region.

For example, Japanese Patent Application Laid-Open No. 58-45999 discloses the former, which utilizes the infrared reflectivity and infrared absorptivity of white ink and black ink to provide mechanically readable information in the form of a bar code or the like. It describes that a mark is applied to a medium or the like, infrared light is irradiated on the medium, the mark is scanned, and the recorded information is read by binarizing the intensity of the reflected infrared light. It describes that a visible light is shielded so that information is not read illegally, and a concealing layer that transmits infrared rays is formed to prevent the information from being easily read by visible light.

The latter is combined with a black infrared-absorbing ink using carbon, which has the same visual appearance but has a difference in spectral characteristics in the infrared region, to determine the authenticity of a specific portion of a printed matter. It is used when information or the like is concealed and the authenticity discrimination information is read out based on the presence or absence of reading in the infrared region at the time of collation, and the validity is confirmed based on the presence or absence or trueness. For example, as a black ink used as a dummy and having no absorption in the infrared region, three primary colors of cyan (blue), yellow (yellow), and magenta (red) process inks are mixed and used as an infrared transmitting ink composition.
Thus, two types of ink compositions having different optical characteristics have been used.

[0005] In particular, in the latter case, specific authenticity discrimination information is formed and concealed in the same color according to marks, patterns, designs, characters, numbers, etc. in printed matter, so that it is almost the same as a real one using a copying machine. Even if it is copied to, since the copy has absorption in the infrared region as a whole, the authenticity identification information cannot be confirmed by verification by infrared irradiation,
It is possible to easily determine the authenticity. In addition, since the genuine article looks through a portion formed of ink having no absorption in the infrared region, the authenticity determination information can be easily confirmed.

[0006]

However, in the printed matter created at the time of creation under the above conditions, the authenticity discrimination information is recognized by a collation device using infrared rays, except in the case of confirmation. Although it is not possible to do so, especially when an ink made of organic materials that does not absorb in the infrared region (hereinafter referred to as infrared transmitting ink) is used, discoloration, discoloration, etc. occur over time, and infrared absorbing ink and infrared transmitting ink Since the two types of ink appear as a color difference, there is a problem in that the concealed true / false discrimination information is known. In addition, the infrared transmitting ink composition, which has been produced by mixing the three primary colors of process inks that do not absorb in the infrared region, which has been conventionally used, has a problem in various resistances in practical use, such as light resistance, heat resistance, and solvent resistance. Had.

Accordingly, the present invention provides a color ink which is visually the same color as a black ink using carbon as a pigment, has light absorption in the visible region, has no absorption in the infrared region, and has light resistance, heat resistance, and solvent resistance. It is an object of the present invention to provide an infrared-transmitting ink composition having various resistances, such as ink resistance.

[0008] The present invention has been made to achieve the above object.
The invention according to claim 1 is an ink composition having an absorption in a visible region and a light transmittance in an infrared region, wherein a main component of a coloring agent of the ink composition is bismuth sulfide, and An infrared transmitting ink composition, wherein the ink composition is black.

According to a second aspect of the present invention, there is provided the infrared ray transmitting ink composition according to the first aspect, wherein the infrared ray transmitting ink composition has an absorption in a visible region and a light transmittance in an infrared region. Polymers, monomers, photopolymerization initiators,
It is composed of an auxiliary agent and the content of the ultraviolet curable resin component is 7
An infrared-transmitting ink composition comprising 0.0 to 90.0% by weight, and a content of a coloring material composed of bismuth sulfide fine powder is 10.0 to 30.0% by weight.

According to a third aspect of the present invention, there is provided the ink composition according to the first aspect, which has an absorption in a visible region and a light transmittance in an infrared region. The content of an oxidatively polymerizable resin component comprising a polymer, a monomer, a photopolymerization initiator, and an auxiliary agent is 70.
0 to 90.0% by weight, the content of the coloring material composed of bismuth sulfide fine powder is 10.0 to 30.0% by weight, and the content of the dryer is 1 to 5% by weight. This is an infrared transmitting ink composition.

[0011] The invention according to claim 4 is the invention according to claims 1, 2,
3. The infrared transmitting ink composition according to 3, wherein the bismuth sulfide fine powder is 0.5 μm or less.

[0012]

According to the infrared transmitting ink composition of the present invention, it has high absorbency in the visible region, high transmittance in the infrared region, and various resistances such as light resistance, heat resistance, and solvent resistance. Having.

[0013]

Embodiments of the present invention will be described below in detail.

According to the present invention, the bismuth sulfide fine powder, as a pigment (or coloring material), absorbs light in the visible region, that is, conceals a lower layer portion when laminated, and exhibits a characteristic of transmitting light in the infrared region. It has been found, and has extremely high chemical stability, and is excellent in light resistance, heat resistance, solvent resistance and the like. In particular, by setting the particle size to 0.50 μm or less, the transmission characteristics in the infrared region are improved.

The infrared transmitting ink composition of the present invention containing bismuth sulfide fine powder as a main component of a coloring material comprises an ultraviolet curable ink comprising a prepolymer, a monomer, a photopolymerization initiator and an auxiliary agent; There is an oxidative polymerization type ink composed of a resin, linseed oil, a dryer and the like.

The UV-curable ink has a UV-curable resin component content of 70.0 to 90.0% by weight and a bismuth sulfide fine powder content of 10.0 to 30.0% by weight. It is an ink, and the particle size of the bismuth sulfide fine powder is 0.50 μm or less.

The oxidative polymerization type ink has a content of the oxidatively polymerizable resin component of 70.0 to 90.0% by weight,
The content of the dryer is 1 to 5% by weight, and the content of the bismuth sulfide fine powder is 10.0 to 30.0% by weight.
It is a black ink and the particle size of the bismuth sulfide fine powder is 0.5
0 μm or less.

The bismuth sulfide fine powder has a particle size of 0.1.
As the powder is further refined from 50 μm to 0.050 μm, the reflection curve changes from (1) to (2) as shown in the graph showing the spectral characteristics in FIG. Shift to the wavelength side. (The graph is shifted to the left.)

More specifically, an ultraviolet-curable resin component, which is a material for forming an ultraviolet-curable infrared-transmitting ink composition, comprises a prepolymer, a monomer, a photopolymerization initiator,
Consists of auxiliary agents and the like. More specifically, prepolymers include epoxy acrylate, epoxidized oil acrylate, urethane acrylate, unsaturated polyester, polyester acrylate, polyether acrylate, vinyl / acrylate, polyene / thiol, silicone,
Examples thereof include polybutadiene and polystyrylethyl methacrylate.

As the monomer, a monofunctional monomer, 2
There are functional monomers and polyfunctional monomers, and also have a role as a solvent.

Monofunctional monomers include t-butylaminoethyl methacrylate, 2-cyanoethyl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, and 2 (2 -Ethoxyethoxy) ethyl acrylate, 2-ethoxyethyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, 2-hydroxyethyl acrylate,
2-2-hydroxyethyl methacrylate, hydroxypropyl acrylate, isobornyl acrylate, isobornyl methacrylate, isodecyl acrylate,
Isodecyl methacrylate, isooctyl acrylate, n-lauryl acrylate, 2-methoxyethyl acrylate, 2-phenoxyethyl acrylate, stearyl methacrylate, tridecyl methacrylate, N
-Vinylpyrrolidone, tetrahydrofurfuryl acrylate, glycidyl methacrylate and the like.

As the bifunctional monomer, neopentyl glycol acrylate, polyethylene glycol 200
Examples include diacrylate, bisphenol A ethoxyethoxy diacrylate, tripropylene glycol diacrylate, and tetraethylene glycol diacrylate.

Examples of the polyfunctional monomer include pentaerythritol triacrylate, trimethylolpropane triacrylate, propoxytrimethylol, propane triacrylate, and dipentaerythritol hexaacrylate.

Further, as a photopolymerization initiator, a photoradical generator is known, and an intramolecular bond cleavage type and an intermolecular hydrogen abstraction type are known. Examples of the intramolecular bond type include benzoisobutyl ether, benzyldimethyl ketal, and dicarboxylic acid. Ethoxyacetophenone, acyloxime ester, chlorinated acetophenone, hydroxyacetophenone, acylphosphine oxide, and the like. As the intermolecular hydrogen abstraction type, benzophenone, Michler-ketone, dibenzosuberone, 2-ethylanthraquinone, isobutylthioxanthone , Benzyl and the like.

In addition, amines such as n-butylamine, di-n-butylamine and tri-n-butylphosphine allylthiouric acid, sulfones and phosphines are added as photopolymerization initiation aids having a sensitizing effect.

The oxidatively polymerizable resin component, which is a material for forming the infrared-permeable ink composition of the oxidative polymerization type resin, includes phenolic resin, alkyd resin, linseed oil, and the like. Salt is added.

In order to improve printability, a non-reactive resin such as wax, vaseline, polyester, epoxy and triazine resin and a surface modifier are added.

Although not shown, the authenticity discrimination information is formed by the infrared transmitting ink thus produced, and the specific information is hidden in the printed matter by concealing it with the infrared absorbing ink of the same color visually. I can do it. This true / false discrimination information can be discriminated only by collation by infrared irradiation, and has extremely high confidentiality. In particular, the infrared transmitting ink composition of the present invention has high light resistance, heat resistance, solvent resistance, etc. Since the deterioration is small, there is no visible color difference between the infrared transmitting ink and the infrared absorbing ink, and it is possible to reduce the possibility of finding secret information carelessly.

Hereinafter, more specific examples will be described in detail.

[Example 1] In the ultraviolet ray-curable infrared ray transmitting ink composition, the ultraviolet ray-curable resin component is composed of: o oligomers and aliphatic polyester tetraacrylate (trade name: Photomer 5018 manufactured by San Nopco) 60 parts o monomer and trimethylol Propane triacrylate (trade name: Kayarad TMPTA manufactured by Nippon Kayaku Co., Ltd.) 14 parts ○ Polymerization initiator ・ 3,3′-dimethyl-4-methoxybenzophenone (trade name: Kayacure MBP manufactured by Nippon Kayaku Co., Ltd.) 1 part ・ Thioxanson ( Product name: Nisso Cure TX manufactured by Nippon Soda Co., Ltd. 8 parts ・ 4-phenoxydichloroacetophenone (trade name: manufactured by Sandry 1000 Sand) 1 part ○ White vaseline 4 parts, and coloring material further ○ Coloring material ・ Bismuth sulfide Particle size 0 0.2 to 0.6 μm Central particle size 0.4 to 0.5 μm 1 As part of these were kneaded and inked. A test piece was prepared from this ink and measured as follows.

Linear sensor (TCD1500, manufactured by Toshiba)
The infrared cut filter on the surface of C) is an infrared transmission filter (IR made by HOYA) having the spectral characteristics shown in FIG.
83) was used as a detection device to irradiate infrared rays and to detect the reflected light.

FIG. 1 is a graph showing the spectral characteristics of the infrared transmitting ink composition of the present invention. According to the spectral characteristic curve (1) of the infrared transmitting ink composition of Example 1, the visible region (400
〜700 nm), and a large amount of absorption is averaged. In addition, absorption in the infrared region having a wavelength longer than 930 nm was small, and it was confirmed that infrared light was transmitted.
As a comparative example, the spectral characteristics of an ink composed of mixed color black shown below are shown in a spectral characteristic curve (3) of FIG. According to this, even when compared with the infrared transmission ink composition comprising a conventional infrared transmission material, it has the same infrared transmission,
In addition, it shows absorption comparable to that in the visible region.

As a comparative example, the following dye-based ink was kneaded to prepare a dye-based black ink having infrared transmittance. RT-7 yellow (Dainippon Ink) 40 parts RT-7 Beni (Dainippon Ink) 30 parts RT-7 indigo (Dainippon Ink) 30 parts Test pieces having the same concentration as the infrared transmitting ink of the invention were prepared, and their spectral characteristics and light resistance were measured using a fade meter using a carbon arc as a light source.

As a result, the color change of the infrared transmitting ink of the comparative example started to occur 50 hours after irradiation, but the color change of the infrared transmitting ink of the present invention even after 550 hours passed from the irradiation. I couldn't see it.

Next, as a test for chemical resistance, a test piece was 70
When immersion was performed in% ethanol, 1% acetic acid, 1% sodium carbonate, an acid and an alkaline artificial sweat solution, no change in color was observed in the infrared transmitting ink of the present invention.

Further, as a test for resistance to temperature and humidity, the test piece was left in an atmosphere of 40 ° C.-90% for 24 hours, but no change in color was observed in the infrared transmitting ink of the present invention.

Example 2 The bismuth sulfide fine powder as a coloring material had a particle diameter of 0.05 to 0.3 μm and a center particle diameter of 0.1 to 0.3 μm.
Example 1 was repeated except that the particle size was further reduced to 1 to 0.15 μm.
An infrared transmitting ink having the same composition and amount as in Example 1 was prepared and compared with the infrared transmitting ink of Example 1. The results are shown in FIG. The spectral characteristic curve (2) of the second embodiment is different from the spectral characteristic curve (1) of the first embodiment in that the end of the infrared transmission region is shifted to the short wavelength side by about 20 nm and the infrared transmission region is expanded to the short wavelength side. Was confirmed. In each test of light fastness, chemical fastness, and temperature and humidity fastness, good results were similarly obtained without causing color change.

Example 3 Next, in the infrared ray transmitting ink composition of the oxidation polymerization type, the resin component capable of undergoing the oxidation polymerization was used as follows: 25 oligomers and acrylates (trade name: Epicoat Nippon Kayaku Co., Ltd.) 25 monomers Trimethylolpropane triacrylate 15 parts (trade name: Kayarad TMPTA made by Nippon Kayaku Co., Ltd.)-Dipentaerythritol hexaacrylate 60 parts (trade name: Kayarad DPHA made by Nippon Kayaku Co., Ltd.) ○ Polymerization initiator ・ 2,4'-diethyl Thioxanthon 3 parts (trade name: Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) p-Dimethylaminobenzoic acid isoamyl ester 3 parts (trade name: Kayacure DMBI, manufactured by Nippon Kayaku Co., Ltd.) Bismuth Particle size 0.2 to 0.6 μm Central particle size 0.4 to 0.5 μm 10 parts ・ phthalocyanine These were kneaded to form an ink as 0.3 parts of a blue ink. A test piece was prepared from this ink and measured in the same manner as in Example 1.

The infrared transmitting ink composition of this example is
It shows black color visually and hardly differs from carbon black. The absorption in the infrared region was small, and it was confirmed that infrared light was transmitted. Further, the resistance was equivalent to that of the ultraviolet-curable infrared transmitting ink composition of Example 1.

As described above, the infrared transmitting ink composition of the present invention has the same infrared transmittance as the conventional infrared transmitting ink composition comprising an organic dye or pigment infrared transmitting material. They have excellent resistance to deterioration due to aging as represented by light resistance. This is formed into authenticity determination information as described above,
Specific information can be hidden in printed matter by concealing it with infrared absorbing ink that is the same color visually. This true / false determination information can be determined only by verification using infrared irradiation. That is, since the deterioration of the infrared transmitting ink composition due to aging changes is small, there is no visual color difference between the infrared transmitting ink and the infrared absorbing ink, and it is possible to reduce the possibility of inadvertently finding secret information. Because it is possible to use printed matter where security is important, such as banknotes, securities, gift certificates,
It can be used in various fields such as certificate paper.

[0041]

As described above, the infrared absorbing ink composition according to the present invention exhibits the same infrared transmittance as that of a conventional infrared absorbing material obtained by converting an organic dye or pigment into an ink. This makes it difficult to recognize authenticity discrimination information such as marks formed on printed matter in combination with an infrared absorbing ink, but has absorption in the visible light region and little absorption in the infrared region. Authenticity discrimination information can be detected. In addition, it has excellent resistance to deterioration due to aging as represented by light resistance, and it does not cause changes such as fading and discoloration over time. Since the ink does not appear as a color difference, there is no problem that the concealed true / false determination information is known over time. Due to such improved resistance, it can be used in fields where use has been restricted in the past.

[Brief description of the drawings]

FIG. 1 is a graph showing spectral characteristics (reflectance with respect to applied wavelength) of infrared transmitting ink compositions according to Example 1 and Comparative Example.

FIG. 2 is a graph showing spectral characteristics (reflectance with respect to applied wavelength) of the infrared transmitting ink compositions according to Examples 1 and 2.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-264984 (JP, A) JP-A-6-313805 (JP, A) JP-A-5-289336 (JP, A) JP-A-5-289336 270174 (JP, A) JP-A-5-147378 (JP, A) JP-A-6-191162 (JP, A) JP-A-6-107985 (JP, A) JP-A-2-56806 (JP, A) 6-5948 (JP, U) JP-B-46-41931 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20 B41M 3/14 B42D 15/10

Claims (4)

(57) [Claims] 1. An ink composition having absorption in the visible region and light transmittance in the infrared region, wherein the main component of the coloring material of the ink composition is bismuth sulfide, and the ink composition Is an infrared-transmitting ink composition, characterized in that it is black. 2. An ink composition having an absorption in a visible region and a light transmittance in an infrared region, comprising an ink, a prepolymer, a monomer, a photopolymerization initiator, and an auxiliary agent. The content is 70.0 to 90.0% by weight,
The content of the coloring material composed of bismuth sulfide fine powder is 10.0 to
The infrared transmitting ink composition according to claim 1, wherein the content is 30.0% by weight. 3. An ink composition having an absorption in the visible region and a light transmittance in the infrared region, comprising a prepolymer, a monomer, a photopolymerization initiator, an auxiliary agent, etc., and an oxidatively polymerizable resin. 9. The content of the component is 70.0 to 90.0% by weight, and the content of the coloring material composed of bismuth sulfide fine powder is 10.
0 to 30.0% by weight, and the content of the dryer is 1 to
The infrared transmitting ink composition according to claim 1, wherein the content is 5% by weight. 4. The infrared transmitting ink composition according to claim 1, wherein said bismuth sulfide fine powder is 0.5 μm or less.