JP2015010144A - Ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ink of which the color can be visually recognized under visible light, however, the color cannot be visually recognized under ultraviolet irradiation.SOLUTION: Ink includes: a first coloring material having a color under visible light; and a second coloring material developing, under ultraviolet irradiation, a color in a complementary relation with the color of the first coloring material developed under visible light. In the ink, the second coloring material develops, under visible light, a white color, or is colorless, or develops the same color as that of the first coloring material. Because the ink includes the first coloring material developing the color under visible light and the second coloring material developing, under ultraviolet irradiation, the color in a complementary relation with the color of the first coloring material developed under visible light, the first coloring material can be visually recognized under visible light, and under ultraviolet irradiation, the ink develops the white color due to the second coloring material developing the color in a complementary relation with the color of the first coloring material developed under visible light, and consequently a color visually recognized under visible light cannot be visually recognized.

Description

  The present invention relates to an ink that can be visually recognized under visible light but cannot be visually recognized under visible light when irradiated with ultraviolet light (such as black light).

  So-called stealth ink, which is not visible under visible light and visible when irradiated with ultraviolet rays, is used for art purposes such as graphics, posters, wallpaper, and photos, as well as forgery and falsification of paper money, securities, checks and other documents. Often done. Especially for art applications, by using stealth ink, by irradiating ultraviolet rays onto posters and wallpapers that look plain under visible light, vivid images can appear, and printed matter that has an impact on the viewer It is possible to produce.

  For example, as a related technique in which an image can be visually recognized by irradiating excitation light other than visible light although it cannot be recognized under normal visible light, Patent Document 1 discloses that the ink is emitted with excitation light. A technique for expressing black by providing a portion in which no ink is printed in an image to be printed is described. This is based on the fact that when the excitation light is irradiated, the portion where the fluorescent ink is printed emits light, but the portion where the fluorescent ink is not printed does not emit light. If there is an unprinted portion, the portion on which the fluorescent ink is not printed appears dark and black can be recognized.

Japanese Patent Laid-Open No. 10-287034

  By forming an image with stealth ink on an image made with normal CMYK ink, it is possible to express different images under visible light and when irradiated with ultraviolet rays, and can be used in various arts. . However, since normal CMYK inks can be viewed under UV light, images that are visible under UV light can also be viewed under UV light, so that images visible under UV light and images visible under UV light are visible together. There is a problem that the entire image is messed up.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink that can visually recognize a color under visible light but cannot visually recognize this color when irradiated with ultraviolet rays. is there.

The ink of the present invention includes a first color material that is colored under visible light and a second color material that develops a color complementary to the color of the first color material under visible light when irradiated with ultraviolet light. It is what.
The second color material is preferably white, colorless or the same color as the first color material under visible light.

  The ink of the present invention includes a first color material that is colored under visible light and a second color material that develops a color that is complementary to the color of the first color material under visible light when irradiated with ultraviolet rays. Under the light beam, the first color material can be visually recognized, and when the ultraviolet ray is irradiated, the ink of the present invention becomes white by the second color material that develops a color complementary to the color of the first color material under the visible light beam. A color that is visible under visible light becomes invisible. For this reason, for example, when an image of the ink of the present invention and another image of the stealth ink are printed, only the image of the ink of the present invention is visible under visible light, and only the image of the stealth ink is visible during ultraviolet irradiation. Is possible.

  Hereinafter, the ink of the present invention will be described in detail. The ink of the present invention includes a first color material that is colored under visible light and a second color material that develops a color that is complementary to the color of the first color material under visible light when irradiated with ultraviolet light. Here, visible light means a wavelength of 380 to 750 nm, and ultraviolet light means a wavelength of less than 380 nm. The color complementary to the color of the first color material under visible light is 180 ° ± when the position facing the color of the first color material under visible light in the hue circle is 180 °. It means the color at the 20 ° position. Preferably, the second color material is a color at a position of 180 ° ± 15 ° with respect to the first color material, and further a color at a position of 180 ° ± 10 °.

  Specifically, for example, a first color material that is purple under visible light and a second color material that is white under visible light and develops a yellow-green color that is complementary to purple of the first color material when irradiated with ultraviolet light. When an image is formed with ink, a purple image is visible under visible light, and when irradiated with ultraviolet light, the color of the second color material, which is complementary to the purple of the first color material, becomes white, and when irradiated with ultraviolet light, the image becomes white. It becomes invisible. In addition, a first color material that is yellow under visible light and a second color material that develops blue that is the same color as the first color material under visible light and blue that is complementary to yellow of the first color material when irradiated with ultraviolet light. When an image is formed with ink, a yellow image is visible under visible light, and when irradiated with ultraviolet light, the second color material, which is complementary to yellow of the first color material, becomes white due to blue, and when exposed to ultraviolet light, the image is visible. become unable.

  In addition, when an image is formed with an ink containing a yellow first color material under visible light, a white color under visible light and a second color material that develops a blue color complementary to yellow of the first color material when irradiated with ultraviolet rays. Under visible light, a yellow image can be visually recognized, and when irradiated with ultraviolet light, the second color material, which is complementary to yellow of the first color material, becomes white due to blue, and when irradiated with ultraviolet light, the image becomes invisible. Furthermore, the color development under visible light may be performed by mixing the first color material and the second color material. For example, in order to make yellow color development under visible light, the first color material of yellowish green under visible light and An orange second colorant may be mixed under visible light. In this case, when the second color material is purple, which is a complementary color of yellowish green when irradiated with ultraviolet rays, the image cannot be visually recognized when irradiated with ultraviolet rays. However, in this example, yellow under visible light is colored by mixing a yellow-green first color material under visible light and an orange second color material under visible light, so the vividness is low. . For this reason, the second color material is preferably white, colorless or the same color as the first color material under visible light.

  The second colorant is preferably a fluorescent dye from the viewpoint of versatility. Examples of the second color material include CARTAX CXDP (yellowish green) manufactured by Clariant Japan Co., Ltd., Lumisys E-300 (red), Lumisys E-400 (red), and Lumisys T- of Central Techno Co., Ltd. 500 (green), Lumisis T-600 (green), Lumisis Y-700 (green), Lumisis G-900 (green), Lumisis B-800 (blue), Lumisis WB-1000 (blue), Lumisis YB-1200 ( Blue), Luminous UV phosphor series, UV phosphor UVP-1 (purple), UV phosphor UVB-1 (blue), UV phosphor UVG-1 (green), UV phosphor UVG-2 ( Green), UV phosphor UVR-1 (red), UV phosphor UVR-2 (red), and the like. In addition, the color in the parenthesis of the color material is a color at the time of ultraviolet irradiation.

  The first color material may be either a pigment or a dye, and is not particularly limited as long as it is colored. Here, the color means a color material other than white and black. As the pigment, regardless of whether it is an organic pigment or an inorganic pigment, those generally used in the technical field of printing can be used. Specifically, cadmium red, chrome yellow, cadmium yellow, chromium oxide, pyridian, titanium Cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, dioxazine pigment, selenium pigment, perylene pigment, thioindigo pigment, quinophthalone pigment , Metal complex pigments and the like can be preferably used. These pigments may be used alone or in combination of two or more. When using in combination of 2 or more types, the color which mixed 2 types turns into a 1st color material and a color.

  As the dye, depending on the type of ink, for example, an azo, anthraquinone, azine or the like water-soluble dye or oil-soluble dye can be used.

  The first color material and the second color material are preferably contained in a range of 0.01 to 20% by mass with respect to the total amount of ink. The mass ratio of the first color material and the second color material varies depending on the type of color material used, the intensity of fluorescence of the second color material, and the like, but the total amount of the first color material and the second color material is 1. In this case, it is preferable that the first color material has a mass ratio in the range of 0.1 to 0.9, preferably in the range of 0.2 to 0.8, and more preferably in the range of 0.3 to 0.7.

  The type of the ink of the present invention is not particularly limited, and emulsion ink (water-in-oil type, oil-in-water type), non-aqueous ink (solvent ink, oil-based ink), water-based ink, ultraviolet curable ink, hot-melt ink It can be applied to both.

  When the ink of the present invention is a water-in-oil emulsion ink, the first color material and the second color material may be contained in either the water phase or the oil phase. The first color material and the second color material may be included in separate phases, such as an oil phase. The oil phase is mainly composed of a resin, a solvent, and an emulsifier, but may contain a known component such as a gelling agent and an antioxidant as necessary. The ratio of the oil phase is preferably 20 to 60% by mass and more preferably 30 to 50% by mass with respect to the total amount of ink.

Resins impart viscosity to the ink and improve the stability of the emulsion, and those that dissolve in the oil phase are used. As the resin, for example, rosin, gilsonite, rosin ester, maleic acid resin, phenol resin, alkyd resin, petroleum resin, acrylic resin, amino resin, urethane resin, cellulose resin, natural rubber derivative resin and the like can be preferably used. Alkyd resins and phenol resins can be used more preferably. A reaction product of an alkyd resin or rosin-modified resin with an aluminum chelate compound or aluminum alcoholate can also be preferably used.
The content of the resin is preferably 3 to 25% by mass, and more preferably 8 to 20% by mass with respect to the total mass of the ink.

  As the solvent, any of a nonpolar organic solvent and a polar organic solvent can be used. These may be used alone or in combination of two or more as long as they form a single phase. Preferred examples of the nonpolar organic solvent include aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents. Examples of the aliphatic hydrocarbon solvent and alicyclic hydrocarbon solvent include paraffinic, isoparaffinic, and naphthenic solvents. For example, what is sold with the following brand names is mentioned. Teclean N-16, Teclean N-20, Teclean N-22, Naphthezol L, Naphthezol M, Naphthezol H, No. 0 Solvent L, No. 0 Solvent M, No. 0 Solvent H, Isosol 300, Isosol 400, AF Solvent No. 4, AF Solvent No. 5, AF Solvent No. 6, and AF Solvent No. 7 (all manufactured by JX Nippon Oil & Energy Corporation); Isopar G, Isopar H, Isopar L, Isopar M, Exol D40, Exol D80, Exol D100, Exol D130 and Exol D140 (both manufactured by ExxonMobil). Examples of the aromatic hydrocarbon solvent include grade alkene L, grade alkene 200P (alkylbenzene, both manufactured by JX Nippon Oil & Energy Corporation), Solvesso 200 (manufactured by ExxonMobil Corporation), and the like.

  Preferable examples of the polar organic solvent include ester solvents, alcohol solvents, higher fatty acid solvents, ether solvents and the like. Ester solvents include methyl laurate, isopropyl laurate, isopropyl myristate, isopropyl palmitate, isostearyl palmitate, methyl oleate, ethyl oleate, isopropyl oleate, butyl oleate, methyl linoleate, isobutyl linoleate , Ethyl linoleate, isopropyl isostearate, soybean oil methyl, soybean oil isobutyl, tall oil methyl, tall oil isobutyl, diisopropyl adipate, diisopropyl sebacate, diethyl sebacate, propylene glycol monocaprate, tri-2-ethylhexanoic acid tri Methylolpropane, glyceryl tri-2-ethylhexanoate; alcoholic solvents such as isomyristyl alcohol, isopalmityl alcohol, isostearyl alcohol Oleyl alcohol; higher fatty acid solvents such as isononanoic acid, isomyristic acid, hexadecanoic acid, isopalmitic acid, oleic acid, isostearic acid; ether solvents such as diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether And propylene glycol dibutyl ether.

  Vegetable oils can also be used. Examples of vegetable oils include vegetable fats such as palm oil and palm oil, soybean oil, olive oil, castor oil, and linseed oil. The content of the solvent and vegetable oil is preferably 1 to 50% by mass and more preferably 3 to 20% by mass with respect to the total amount of the ink.

  The emulsifier is used to constitute a water-in-oil emulsion, and any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant may be used. Among these, it is preferable to use a nonionic surfactant from the viewpoint of the emulsifiability and storage stability of the water-in-oil emulsion.

  Specifically, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monooleate, sorbitan sesquioleate, sorbitan fatty acid esters such as sorbitan monoisostearate, glyceryl monostearate, hexaglyceryl tetraoleate, decaglyceryl deca (Poly) glycerin fatty acid esters such as oleate and hexaglyceryl pentaoleate, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbite fatty acid ester, propylene glycol fatty acid ester, (poly) ethylene glycol fatty acid ester , Polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alcohol Phenyl ethers, polyoxyethylene (hardened) can be exemplified preferably castor oil and the like. The said nonionic surfactant may be used independently and can also be used in combination of 2 or more types as appropriate.

In the aqueous phase, in addition to water, a water evaporation inhibitor (or antifreezing agent), an electrolyte, a pH adjuster, an antioxidant and the like can be included as necessary.
Specific examples of water evaporation inhibitors (or antifreeze agents) include water-soluble organic solvents such as polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, and glycerin. The content is preferably 1 to 20% by mass and more preferably 3 to 15% by mass with respect to the total amount of the aqueous phase.

  Examples of the electrolyte include sodium sulfate, magnesium sulfate, potassium hydrogen phosphate, sodium citrate, potassium tartrate, sodium borate and the like, and the content thereof is 0.1 to 5.0% by mass with respect to the total amount of the aqueous phase. It is preferable that it is 0.5-2.0 mass%.

  The water-in-oil emulsion ink can be prepared by the following procedure. First, after dispersing a 1st color material and a 2nd color material in resin with a well-known disperser, it dilutes with a solvent and adds another oil phase component. A known stirrer can be used for dilution. The aqueous phase can be prepared by mixing and dissolving the components of the aqueous phase in water with a stirrer. And a water-in-oil emulsion ink can be obtained by dripping an aqueous phase in the oil phase under stirring using a well-known emulsifier. The conditions adopted for carrying out these dispersion, dilution, emulsification and the like can be appropriately selected.

  When the ink of the present invention is an oil-based ink, it is composed of at least a solvent in addition to the first color material and the second color material. If necessary, known components such as a dispersant, a resin, and an antioxidant are added. It can be included as appropriate. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, and a high molecular weight unsaturated acid ester. , Modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester, polyoxyethylene nonyl phenyl ether, polyester polyamine, stearylamine acetate, etc. .

  Among these, polymer dispersants are preferably used, and examples thereof include those sold under the following trade names: Solsperse 5000 (phthalocyanine ammonium salt type), 11200 (polyamide type), 13940 (polyesteramine type) ), 17000, 18000 (fatty acid amine series), 22000, 24000, and 28000 (all manufactured by Nippon Lubrizol Corporation); EFKA 400, 401, 402, 403, 450, 451, 453 (modified polyacrylate), 46, 47, 48, 49, 4010, and 4055 (modified polyurethane) (all manufactured by Efka CHEMICALS); Demol P, EP, Poise 520, 521, 530, and Homogenol L-18 (polycarboxylic acid type polymer surfactant) ) (Both Kao Corporation Dispalon KS-860, KS-873N4 (amine salt of high molecular polyester) (all manufactured by Enomoto Kasei Co., Ltd.); Discol 202, 206, OA-202, and OA-600 (non-chain polymer non-polymer) (Ionic system) (both manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); ANTARON V216 (vinyl pyrrolidone-hexadecene copolymer) (manufactured by IPS Japan Co., Ltd.). Of these, polyamide-based and polyesteramine-based are more preferable. The content of the dispersant may be an amount that can sufficiently disperse the first color material and the second color material in the ink, and is usually about 1 to 10% by mass with respect to the total amount of the ink. When a dye or a self-dispersing pigment is used as the color material, a dispersant may not be included.

  As the solvent for the oil-based ink, a nonpolar organic solvent, a polar organic solvent, or a mixture thereof can be used in the same manner as the solvent for the water-in-oil emulsion ink described above.

  The polar organic solvent is preferably contained in an amount of 10% by mass or more based on the total amount of the oil-based ink. Furthermore, from the viewpoint that sufficient stability can be obtained on a storage container or a printing press, the ratio of the polar organic solvent to the solvent in the ink is more preferably 20 to 80% by mass.

  In addition to the above components, the oil-based ink may contain conventional additives. Additives include surfactants such as anionic, cationic, amphoteric or nonionic surfactants, antioxidants such as dibutylhydroxytoluene, propyl gallate, tocopherol, butylhydroxyanisole, and nordihydroguaiare. And tic acid.

The oil-based ink can be prepared by, for example, supplying all components in a known disperser such as a bead mill in a lump or divided and dispersing them, and if desired, passing them through a known filter such as a membrane filter.
Examples of emulsion ink and oil-based ink will be shown below as examples of the ink of the present invention.

[Preparation of emulsion ink]
(Examples 1-6, Comparative Examples 1 and 2)
According to the formulation shown in the following Table 1 (the numerical values shown in the table are parts by mass), inks of Examples and Comparative Examples were prepared according to the following procedure. First, a part of the first color material, the second color material, the resin, and the solvent was mixed and dispersed by a three-roll mill. The remaining solvent, unsaturated oil and fat, antioxidant, and emulsifier were added thereto, and stirred sufficiently to obtain an oil phase component. Separately from this, water phase component materials were mixed and stirred to obtain an aqueous phase component. The oil phase component was emulsified with a stirrer while gradually adding the water phase component to obtain a water-in-oil emulsion ink.

In addition, the detail of the raw material of Table 1 is as follows, and all the used fluorescent dyes are white under visible light.
・ Purple pigment: Fastgen Super Bio Red RN (manufactured by DIC Corporation)
Green pigment: Fastgen Green S (manufactured by DIC Corporation)
・ Red pigment: Shimura Red 3075 (manufactured by DIC Corporation)
Yellow pigment: Shimura Fast Yellow 4090G (manufactured by DIC Corporation)
・ Fluorescent dye (yellowish green): CARTAX CXDP (manufactured by Clariant Japan Co., Ltd.)
・ Fluorescent dye (red): Lumisis E-400 (manufactured by Central Techno Co., Ltd.)
・ Fluorescent dye (blue): Lumisys B-800 (manufactured by Central Techno Co., Ltd.)
・ Alkyd resin: Hariftal 3371 (manufactured by Harima Chemicals)
AF solvent 6: Nonpolar organic solvent (manufactured by JX Nippon Oil & Energy Corporation)
・ Soybean oil: Nissin soybean white squeezed oil (Nisshin Oilio Group Co., Ltd.)
・ BHT: Dibutylhydroxytoluene (manufactured by Tokyo Chemical Industry Co., Ltd.)
・ Sorbitan monooleate: Emazole O-10V (manufactured by Kao Corporation)

(Evaluation)
Images were printed on printing paper with a stencil printing machine (lithograph RZ970: manufactured by Riso Kagaku Kogyo Co., Ltd.) using the emulsion inks obtained in Examples and Comparative Examples. The obtained printed matter was irradiated with ultraviolet rays of 365 nm, visually confirmed and evaluated according to the following criteria.
A: White color was obtained B: Almost white but slightly colored C: White color was not obtained Table 1 shows the evaluation results together with the ink formulation.

  As shown in Table 1, the image of the comparative ink was visually recognized by ultraviolet irradiation, but the ink of the example developed white or almost white color instead of the colors of the first color material and the second color material by ultraviolet irradiation. Obtained.

[Preparation of oil-based ink]
(Example 7)
5 parts of fluorescent dye (CARTAX CXDP, manufactured by Clariant Japan Co., Ltd.), 5 parts of purple pigment (Fastgen Super Bio Red RN, manufactured by DIC Corporation), 3 parts of dispersant (Solsperse 28000, manufactured by Nippon Lubrizol Co., Ltd.) 47 parts of methyl oleate (Exepal M-OL, manufactured by Kao Corporation) and 40 parts of Isopar G (manufactured by JX Nippon Oil & Energy Corporation) are mixed and used in a bead mill (using zirconia beads having a diameter (φ) of 0.5 mm). The obtained dispersion was filtered through a membrane filter (opening diameter: 3 μm) to prepare an oil-based ink. This ink was filled in an ink cartridge, and printing was performed with an inkjet printer (ORPHIS X9050: manufactured by Riso Kagaku Corporation). When the obtained printed matter was irradiated with ultraviolet rays of 365 nm, white color was obtained.

  As is clear from the above examples, according to the ink of the present invention, it is possible to visually recognize the color under visible light, but this color cannot be visually recognized when irradiated with ultraviolet rays. If another image is formed with stealth ink on the image produced in step 1, it is possible to express different images under visible light and ultraviolet irradiation, and it can be applied to art, etc. that produces different images under different light. Is possible.

Claims (2)

  An ink comprising: a first color material which is colored under visible light; and a second color material which develops a color complementary to the color under visible light of the first color material when irradiated with ultraviolet rays.   The ink according to claim 1, wherein the second color material is white, colorless, or the same color as the first color material under visible light.