JP2006233034A - Mirror ink and method of mirror printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mirror ink which allows a low temperature baking, gives a thin metal film having a good mirror gloss and contributes to higher quality and functions of various printings, and a method of mirror printing. <P>SOLUTION: The mirror ink uses metal particles having an average particle size of 1-100 nm. The method of mirror printing involves a step to print with the mirror ink, a step to irradiate printed matter printed with the mirror ink with actinic rays and a step to heat the printed matter at ≤150°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a printing ink and a printing method for forming a character, figure, or pattern image having mirror gloss or specular reflection.

Conventionally, when forming images of characters, figures, and patterns with specular reflectivity on a transparent film, etc., by depositing a metal such as aluminum on the entire printed surface and then removing unnecessary parts with chemicals, etc. There is a method for forming a predetermined image having mirror gloss. Alternatively, masking corresponding to the image to be formed in advance is performed on the transparent film, and then silver fine powder is vapor-deposited on the entire surface on one side of the masked transparent film by a metal vapor deposition step, and then the masking is removed. Thus, there is a method for forming a predetermined image having a mirror gloss composed of the remaining portion.

On the other hand, as a method by printing, as disclosed in JP-A-9-268269 and JP-A-2003-315511, mirror ink using scaly metallic powder or aluminum foil pieces is printed by gravure printing, flexographic printing or silk screen printing, and mirror surface is used. A method of imparting sex has been performed.

The above-mentioned conventional technique using a vapor deposition method requires a large-scale equipment because it requires a vapor deposition process, and has a lot of man-hours. For pattern formation using, powerful drugs such as strong acids are often used, and wastewater treatment is required, which is not preferable from the viewpoint of environmental conservation. Furthermore, in the pattern forming method having specular reflectivity by printing using scaly metallic powder or aluminum foil, it is necessary to have a thickness of about 3 μm in order to obtain specularity and concealment. However, since it is expensive, it is not as expensive as the vapor deposition method, and the method of fixing the resin by solvent removal or oxidative polymerization is used as a drying means, and it takes time, so that it has a defect in productivity.
Japanese Patent Laid-Open No. 9-268269 JP 2003-315511 A

As a result of intensive research, the inventor added an ingredient that generates an acid component by irradiating energy rays to metal fine particles having a particle size of 1 to 100 nm that are coated with a dispersant and have fluidity at room temperature, and irradiated with energy rays. By doing so, the dispersant can be instantaneously detached from the metal fine particles, and the metal fine particles having a particle size of 1 to 100 nm are different from the behavior of metal particles of about 1 μm and melt and sinter at a lower temperature as the particle size becomes smaller. Therefore, the inventors have found that a thin film having very good specular reflectivity can be obtained by melting and sintering metal fine particles at a low temperature of 25 to 150 ° C., thereby completing the present invention.

That is, the present invention relates to a mirror ink characterized by using metal fine particles having an average particle diameter of 1 to 100 nm.
Further, the present invention is characterized in that the metal species of the metal fine particles are one kind selected from gold, silver, copper, platinum, palladium, rhodium, ruthenium, indium, nickel, aluminum, or a mixture or alloy of two or more thereof. It relates to the above mirror ink.
Furthermore, the present invention relates to the mirror ink, wherein the metal fine particles are coated with a dispersant which is an amine, an alcohol, a phenol, a thiol, or a mixture thereof.

Furthermore, this invention relates to the said mirror ink characterized by including the compound which generate | occur | produces an acid component by energy ray irradiation.
Further, the present invention provides the above mirror, wherein the compound that generates an acid component upon irradiation with energy rays is one kind selected from an onium compound, a sulfone compound, a halide, and an iron allene complex, or a mixture of two or more of these. It relates to ink.

Furthermore, the present invention relates to the above mirror ink, wherein the energy beam is an electron beam or an ultraviolet ray. Furthermore, this invention relates to the mirror surface printing method which has the process of printing the said mirror ink on a to-be-printed body, the process of irradiating an energy ray to the to-be-printed body which printed the mirror ink, and the process of heating below 150 degreeC.

In the present invention, a composition in which fine particles of a metal or alloy such as gold, silver, copper, etc. are stably dispersed in a liquid uses an energy ray, so that sintering is instantaneously performed at a temperature of 25 ° C. to 150 ° C. A metallic thin film with a specular gloss can be obtained, which can contribute to the high quality and high functionality of various printing. The mirror ink composed of the metal fine particles is excellent in transferability and concealment compared with the conventional mirror ink using scaly metallic powder or aluminum foil pieces, and as a method for printing on a printing medium, gravure printing, flexographic printing, In addition to silk screen printing, techniques such as offset printing, letterpress printing, and inkjet can be used.

Embodiments of the present invention will be described below.

In the state before sintering by energy beam irradiation and heat treatment, the surface of the metal fine particle is an organic compound capable of coordinating with the metal element, such as 2-methylaminoethanol, diethanolamine, butoxypropylamine, diethylmethylamine, 2-dimethyl. It is coated with amine compounds such as aminoethanol and methyldiethanolamine, alicyclic thiols such as alkylamines, ethylenediamine, alkylalcohols, ethylene glycol, propylene glycol, alkylthiols, cyclohexylthiol, and ethanedithiol. ing. Due to this coating action, each of the metal particles is dispersed in a stable shape in the organic solvent.

Examples of the metal species of the fine metal particles used in the present invention include gold, silver, copper, platinum, palladium, rhodium, ruthenium, indium, nickel, and aluminum. Of these, silver is preferably used as the metal species in order to maximize the effects of the present invention. Two or more metal species can be mixed and used.

The metal fine particles used in the present invention can be added in the range of 10 to 95% in the ink, and can be appropriately selected according to various printing methods. Specifically, 40 to 60% for gravure printing, 60 to 80% for flexographic printing, 70 to 90% for silk screen printing, and 80 to 95% for offset printing are preferred. However, the present invention is not limited to this because a viscosity suitable for printing can be imparted.

As a compound that generates an acid upon irradiation with energy rays used in the present invention, for example, a chemical amplification type photoresist or a compound used for photocation polymerization is used (edited by Organic Electronics Materials Research Group, “Organic Materials for Imaging”). Bunshin Publishing (1993), pages 187-192). Examples of compounds suitable for the present invention are listed below. First, B (C6F5) 4, PF6, AsF6, SbF6, and CF3SO3 salts of aromatic onium compounds such as diazonium, ammonium, iodonium, sulfonium, and phosphonium can be exemplified. Those having a borate compound as a counter anion are preferred because of their high acid generation ability. Examples of onium compounds include bis (alkyl (C = 10-14) phenyl) iodonium hexafluorophosphate, 4-methylphenyl [4- (1methylethyl) phenyl] iodonium tetrakis (pentafluorophenyl) borate, and An example is illustrated.

Secondly, sulfonated substances that generate sulfonic acid can be mentioned. An example of a specific compound is illustrated below.

Thirdly, a halide that generates hydrogen halide can also be used. Examples of specific compounds are shown below.

Fourthly, an iron allene complex can be mentioned.

In the present invention, the compound that generates an acid upon irradiation with energy rays is preferably blended in an amount of 0.1 to 100 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the metal fine particles. If the blending amount is less than 0.1 parts by weight, it is difficult to obtain sufficient sensitivity, and if it exceeds 100 parts by weight, disqualification may occur during metal sintering by irradiation with energy rays and heating, and good specular reflectivity may be impaired. . Therefore, it is preferable that the addition amount of the compound acid generator that generates an acid upon irradiation with energy rays is the minimum necessary.

The energy rays used in the present invention are an ultra-low acceleration voltage electron beam irradiation apparatus having an acceleration voltage of 100 kV or less, a low acceleration voltage electron beam irradiation apparatus having an acceleration voltage of 100 to 300 kV, a medium acceleration voltage electron beam irradiation apparatus of 300 to 800 kV, and 1000 kV. An electron beam generated by the above high acceleration voltage electron beam irradiation apparatus and / or ultraviolet light or visible light having a wavelength of 180 to 500 nm can be used.

The acceleration voltage of the electron beam contributes to the thickness direction of the metal fine particles, and the electron beam can be transmitted to a deeper position as the acceleration voltage is higher. However, an excessive acceleration voltage may cause damage to the pair to be printed on which metal fine particles are printed, and it is preferable to use a low acceleration voltage electron beam irradiation apparatus of 300 kV or less.

Examples of the light generation source of ultraviolet light or visible light having a wavelength of 180 to 500 nm include, for example, a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal is a ride lamp, a chemical lamp, a black light lamp, a mercury-xenon lamp, an excimer lamp. , Short arc lamp, helium-cadmium laser, argon laser, excimer laser, UV electrodeless lamp, sunlight and the like.

In the present invention, a photoradical generator and a sensitizer having a sensitizing action can be used together with a compound that generates an acid with energy rays in the metal fine particles, if necessary.
Here, the photoradical generator can be roughly classified into a photocleavage type and a hydrogen abstraction type. Examples of the former include benzoins such as benzoin, benzoin methyl ether, benzoin isopropyl ether, and α-acrylobenzoin, benzyl, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one (Irgacure 907: Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone (Irgacure 369: Ciba Specialty Chemicals), benzylmethyl ketal (Irgacure 651: Ciba Specialty Chemicals) 1-hydroxycyclohexyl phenyl ketone (Irgacure 184: manufactured by Ciba Specialty Chemicals), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173: manufactured by Merck), 1- (4- Isopropyl fe ) -2-Hydroxy-2-methylpropan-1-one (Darocur 1116: manufactured by Merck & Co., Inc.), 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 4- (2- Acryloyl-oxyethoxy) phenyl-2-hydroxy-2-propylketone, diethoxyacetophenone (ZLI3331: manufactured by Ciba Specialty Chemicals), Esacure KIP100 (manufactured by Ramberty), Lucillin TPO (manufactured by BASF), bis (2,6 -Dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide (BAPO1: manufactured by Ciba Specialty Chemicals), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (BAPO2: Ciba Specialty Chemicals) Manufactured), BTTB (manufactured by NOF Corporation) , CGI1700 (from Ciba Specialty Chemicals, and the like.

Examples of the latter include benzophenone, p-methylbenzophenone, p-chlorobenzophenone, tetrachlorobenzophenone, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 2-isopropylthioxanthone 2,4-dimethylthioxanthone, 2,4 diethylthioxanthone, 2,4 dichlorothioxanthone, aryl ketone initiators such as acetophenone, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) Dialkylaminoaryl ketone initiators such as benzophenone, isoamyl p-dimethylaminobenzoate, and p-dimethylaminoacetophenone, thioxanthone, xanthone-based and halogen-substituted polycyclic cals Examples include bonyl-based initiators. These can be used alone or in appropriate combinations, but are not limited thereto.

Examples of the sensitizer include compounds such as anthracene, but are not limited thereto.

In the present invention, the compound used as a sensitizer is preferably blended in an amount of 0.1 to 100 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the metal fine particles. If the blending amount is less than 0.1 parts by weight, it is difficult to obtain sufficient sensitivity, and if it exceeds 100 parts by weight, disqualification may occur during metal sintering by irradiation with energy rays and heating, and good specular reflectivity may be impaired. .

Furthermore, in the present invention, an active energy ray binder and a compound that develops a known photocationic polymerization can be added as a component for forming a film on the metal fine particles, if necessary.

The active energy ray-curable binder is a non-reactive resin (innert resin) having a softening point of 50 to 180 ° C. represented by diallyl phthalate resin, or a reactive (radical polymerizable) oligomer, a radical polymerizable monomer, and if necessary It consists of a radical polymerization initiator, a photosensitizer, a pigment as required, and various additives. Examples of the non-reactive resin (innert resin) include ortho to isotype diallyl phthalate resins. Examples of the reactive (radical polymerizable) oligomer include alkyd acrylate, polyester acrylate, epoxy acrylate, and urethane-modified acrylate.

A (meth) acrylic monomer or acrylic oligomer having an ethylenically unsaturated double bond will be described as a radical polymerizable monomer. As the (meth) acrylic monomer having an ethylenically unsaturated double bond, an alkyl (having 1 to 18 carbon atoms) (meth) acrylate as a monofunctional monomer, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl There are (meth) acrylates, hexyl (meth) acrylates, octyl (meth) acrylates, dodecyl (meth) acrylates, stearyl (meth) acrylates, plus benzyl (meth) acrylates, butylphenol, octylphenol or nonylphenol or alkylphenols such as dodecylphenol Ethylene oxide adduct (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, tricyclodecane monomethylol (meth) Acrylate and the like.

Furthermore, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di ( (Meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, pentyl glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalylhydroxy Pivalate di (meth) acrylate (commonly called manda), hydroxypivalyl hydroxypivalate dicaprolactonate di (meth) a Acrylate, 1,6-hexanediol di (meth) acrylate, 1,2-hexanediol di (meth) acrylate, 1,5-hexanediol di (meth) acrylate, 2,5-hexanediol di (meth) acrylate, 1 , 7-Heptanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,2-octanediol di (meth) acrylate di (meth) acrylate, 1,9-nonanediol di (meth) Acrylate, 1,2-decanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 1,2-decanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, 1,2-dodecanediol di (meth) acrylate, 1,14-tetradecanediol di (me ) Acrylate, 1,2-tetradecanediol di (meth) acrylate, 1,16-hexadecanediol di (meth) acrylate, 1,2-hexadecanediol di (meth) acrylate, 2-methyl-2,4-pentanediol Di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 2-methyl-2-propyl-1,3-propanediol di (meth) acrylate, 2,4-dimethyl-2 4-pentanediol di (meth) acrylate, 2,2-diethyl-1,3-propanediol di (meth) acrylate, 2,2,4-trimethyl-1,3-pentanediol di (meth) acrylate, dimethylol Octane di (meth) acrylate, 2-ethyl-1,3-hexanediol di (meth) acrylate, 2,5-dimethyl-2,5- Xanthdiol di (meth) acrylate, 2-methyl-1,8-octanediol di (meth) acrylate, 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, 2,4-diethyl- 1,5-pentanediol di (meth) acrylate, 1,2-hexanediol di (meth) acrylate, 1,5-hexanediol di (meth) acrylate, 2,5-hexanediol di (meth) acrylate, 1, 7-heptanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,2-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,2- Decanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 1,2-decanediol di (meth) ) Acrylate, 1,12-dodecanediol di (meth) acrylate, 1,2-dodecanediol di (meth) acrylate, 1,14-tetradecanediol di (meth) acrylate, 1,2-tetradecanediol di (meth) acrylate 1,16-hexadecanediol di (meth) acrylate, 1,2-hexadecanediol di (meth) acrylate, 2-methyl-2,4-pentanedi (meth) acrylate, 3-methyl-1,5-pentanediol di (Meth) acrylate, 2-methyl-2-propyl-1,3-propanediol di (meth) acrylate, 2,4-dimethyl-2,4-pentanediol di (meth) acrylate, 2,2-diethyl-1 , 3-propanediol di (meth) acrylate, 2,2,4-trimethyl-1,3-pentanediol di (meth) Acrylate, dimethyloloctane di (meth) acrylate, 2-ethyl-1,3-hexanediol di (meth) acrylate, 2,5-dimethyl-2,5-hexanediol di (meth) acrylate, 2-butyl-2 -Ethyl-1,3-propanediol di (meth) acrylate, 2,4-diethyl-1,5-pentanediol di (meth) acrylate tricyclodecane dimethylol di (meth) acrylate, tricyclodecane dimethylol dicapro Lactonate di (meth) acrylate, bisphenol A tetraethylene oxide adduct di (meth) acrylate, bisphenol F tetraethylene oxide adduct di (meth) acrylate, bisphenol S tetraethylene oxide adduct di (meth) acrylate, water-added bisphenol A tetrae Ren oxide adduct di (meth) acrylate, water-added bisphenol F tetraethylene oxide adduct di (meth) acrylate, water-added bisphenol A di (meth) acrylate, water-added bisphenol F di (meth) acrylate, bisphenol A tetraethylene oxide Examples include adduct dicaprolactonate di (meth) acrylate, bisphenol F tetraethylene oxide adduct dicaprolactonate di (meth) acrylate, and the like.

Glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tricaprolactonate tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolhexane tri (meth) acrylate as trifunctional monomers , Trimethylol octane tri (meth) acrylate, pentaerythritol tri (meth) acrylate and the like.

Tetraerythritol tetra (meth) acrylate, pentaerythritol tetracaprolactonate tetra (meth) acrylate, diglycerin tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, ditrimethylolpropane tetracapro Lactonate, tetra (meth) acrylate, ditrimethylolethanetetra (meth) acrylate, ditrimethylolbutanetetra (meth) acrylate, ditrimethylolhexanetetra (meth) acrylate, ditrimethyloloctanetetra (meth) acrylate, dipentaerythritol penta ( (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol hexa (meth) acrylate DOO, tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, dipentaerythritol polyalkylene oxide hepta (meth) acrylate and the like.

Further examples include alkylene oxide adduct (meth) acrylate monomers of aliphatic alcohol compounds, particularly alkylene oxide adduct (meth) acrylate monomers of aliphatic alcohol compounds having C3 to C20 or higher alkylene oxides. Although it can combine individually or in combination of 2 or more types, it is not limited to this.

Examples of the compound that causes photocationic polymerization include photocationically polymerizable monomers, and various known cationically polymerizable monomers can be used. For example, epoxy compounds (aromatics) exemplified in JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and JP-A-2001-220526. Alicyclic, aliphatic, etc.), vinyl ether compounds, oxetane compounds and the like.

A preferable aromatic epoxide is a di- or polyglycidyl ether produced by the reaction of a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin, such as bisphenol A or an alkylene oxide thereof. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or its alkylene oxide adducts, and novolak-type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is mentioned.

Preferred aliphatic epoxides include di- or polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol or Diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or alkylene oxide adduct thereof, polyethylene glycol or alkylene oxide adduct thereof Diglycidyl ethers of polyalkylene glycols such as diglycidyl ethers, polypropylene glycols or diglycidyl ethers of alkylene oxide adducts thereof And the like. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

Among these epoxides, in view of fast curability, aromatic epoxides and alicyclic epoxides are preferable, and alicyclic epoxides are particularly preferable. In the present invention, one of the epoxides may be used alone, or two or more may be used in appropriate combination.

Examples of the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, and trimethylol. Di- or trivinyl ether compounds such as propane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl Vinyl ether, isopropyl vinyl ether, isopropenyl ether -o- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.

In the present invention, one of the above vinyl ether compounds may be used alone, or two or more thereof may be used in appropriate combination.

The oxetane compound is a compound having an oxetane ring, and any known oxetane compound as disclosed in JP-A Nos. 2001-220526 and 2001-310937 can be used.

In this invention, you may combine the said binder component 1 type (s) or 2 or more types. The added amount is 1 to 1000 parts by weight, preferably 5 to 500 parts by weight, based on 100 parts by weight of the metal fine particles. If it is 5 parts by weight or less, the effect as a binder is poor, and if it is 500 parts by weight or more, the joining of metals is hindered and good specular reflectivity cannot be obtained.

The composition of the present invention may contain a solvent. Examples of the solvent used in the present invention include aliphatic hydrocarbons such as hexane, cyclohexane, heptane, alcohols, N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylformamide, N, N— Polar aprotic solvents such as dimethylacetamide and dimethylsulfoxide, ethers such as tetrahydrofuran and dioxane, ketones such as acetone, methyl ethyl ketone and diisobutyl ketone, esters such as ethyl acetate, propylene glycol monomethyl ether acetate and ethyl lactate, toluene And aromatic hydrocarbons such as xylene, and the like. By using these alone or in combination, the viscoelasticity and fluidity of the mirror ink corresponding to various printing methods can be adjusted.

The composition of the present invention contains an amino group and a silane coupling agent having no amino residue, a titanium chelating agent, etc., in order to further improve the adhesion to silicon, silicon nitride, silicon oxide, and phosphorus silicate glass substrates. It can also be added.

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited by these examples.

(Metal fine particle dispersion 1)
Commercially available silver ultrafine particle dispersion (trade name: Independently dispersed ultrafine particle Perfect Silver, Vacuum Metallurgical Co., Ltd.), specifically, silver fine particles 100 parts by mass, alkylamine as dodecylamine 15 parts by mass, organic As a solvent, a dispersion of silver fine particles having an average particle diameter of 8 nm containing 75 parts by mass of toluene was used as metal fine particle dispersion 1.
(Metal fine particle dispersion 2)
Commercially available silver ultrafine particle dispersion (trade name: Independently dispersed ultrafine particle Perfect Silver, Vacuum Metallurgical Co., Ltd.), specifically, silver fine particles 100 parts by mass, alkylamine as dodecylamine 15 parts by mass, organic A paste-like dispersion of silver fine particles was prepared using a dispersion of silver fine particles having an average particle diameter of 8 nm containing 75 parts by mass of toluene as a solvent. Butoxypropylamine and 87.5 parts by weight (vs. Ag solid content: 50 wt%: manufactured by Guangei Chemical Co., Ltd.) were mixed with 500 parts by weight of the silver ultrafine particle dispersion, and the mixture was heated and stirred at 80 ° C. for 1 hour. After stirring, toluene was removed by concentration under reduced pressure.
The solvent-removed mixture was transferred to a 2 L beaker, methanol and 1,000 g were added, and the mixture was stirred at room temperature for 3 minutes and allowed to stand. Ag particles were aggregated and settled by adding methanol as a polar solvent. In the supernatant, a brown methanol solution containing unnecessary organic components was obtained. After removing the supernatant layer, 800 g of methanol was added again, and the mixture was stirred and allowed to stand to remove the supernatant layer. After the washing, the precipitated Ag particles were dried and the remaining methanol was volatilized to obtain a blue fine powder. Toluene and 330 g were added to the obtained fine Ag powder, and Ag particles aggregated by heating and stirring at 70 ° C. for 30 minutes were redispersed. After the stirring, the mixture was filtered through a 0.2 μm membrane filter to obtain a uniform dark blue-colored butoxypropylamine dispersion, which was designated as gold fine particle dispersion 2.

(Adjustment of mirror ink 1)
57 parts by weight of metal fine particle dispersion 1, 3 parts by weight of Wcation Pharmaceutical Co., Ltd. photocationic initiator WPI-113 (bis (alkyl (C = 10-14) phenyl) iodonium hexafluorophosphate), manufactured by Toagosei Co., Ltd. Mirror ink 1 for gravure printing with a viscosity of 50 mPa · s was prepared by blending 10 parts by weight of Aronix M-220 (TPGDA tripropylene glycol diacrylate) and 30 parts by weight of toluene and stirring at 400 rpm for 1 minute.

(Adjustment of mirror ink 2)
67 parts by weight of metal fine particle dispersion 2, 3 parts by weight of Wiko Pharmaceutical Co., Ltd. photocation initiator WPI-113 (bis (alkyl (C = 10-14) phenyl) iodonium hexafluorophosphate), manufactured by Toagosei Co., Ltd. Mirror ink 2 for flexographic printing having a viscosity of 500 mPa · s was prepared by blending 10 parts by weight of Aronix M-220 (TPGDA tripropylene glycol diacrylate) and 20 parts by weight of toluene and stirring at 400 rpm for 1 minute.

(Adjustment of mirror ink 3)
77 parts by weight of the metal fine particle dispersion 1, 3 parts by weight of Wcation Pharmaceutical Co., Ltd. photocation initiator WPI-113 (bis (alkyl (C = 10-14) phenyl) iodonium hexafluorophosphate), manufactured by Toagosei Co., Ltd. Mirror ink 3 for silk screen printing having a viscosity of 30 Pa · s was prepared by blending 10 parts by weight of Aronix M-220 (TPGDA tripropylene glycol diacrylate) and 10 parts by weight of toluene and stirring at 400 rpm for 1 minute.

(Adjustment of mirror ink 4)
87 parts by weight of fine metal particle dispersion 2, 3 parts by weight of Wiko Pharmaceutical Co., Ltd. photocation initiator WPI-113 (bis (alkyl (C = 10-14) phenyl) iodonium hexafluorophosphate), manufactured by Toagosei Co., Ltd. 10 parts by weight of Aronix M-220 (TPGDA tripropylene glycol diacrylate) was blended and stirred at a high speed mixer of 400 rpm for 1 minute to prepare a mirror ink 4 for offset printing and letterpress printing having a viscosity of 50 Pa · s.

(Examples 1-4)
Mirror inks 1 to 3 were applied onto a 50 μm-thick PET film using a bar coater # 3. Mirror ink 4 was developed on the same PET film under the condition of an RI tester roll ink overlay of 0.4 cc. Ultraviolet rays were irradiated five times at a conveyor speed of 10 m / min under a 160 w / cm air-cooled high-pressure mercury lamp with an ultraviolet irradiation device manufactured by Igraphic Co., Ltd.
The specular gloss value was defined as a value obtained by measuring the obtained printed matter through an N filter that attenuates the amount of light at an incident angle of 60 ° and a reflection angle of 60 ° of a gloss meter manufactured by Murakami Color Giken. Table 1 shows the measurement results.

(Examples 5 to 8)
The ink was cured in the same manner as in Examples 1 to 4, except that instead of ultraviolet rays, an electron beam irradiation device “MinEB” manufactured by Toyo Ink Manufacturing Co., Ltd. was used and an electron beam of 1000 kGy was irradiated at an acceleration voltage of 50 kV. The specular gloss value of the printed material is also shown in Table 1.

(Comparative Example 1) Mirror ink MIR-9100 (deposited aluminum foil dispersion type) manufactured by Teikoku Mfg. Co., Ltd. was applied to a PET film with a film thickness of 3 μm using a bar coater and dried in an oven at 50 ° C. for 30 minutes. Table 1 shows the specular gloss value of the printed material that was made to produce a mirror surface printed material.

Claims (7)

A mirror ink characterized by using metal fine particles having an average particle diameter of 1 to 100 nm. The metal species of the metal fine particles is one selected from gold, silver, copper, platinum, palladium, rhodium, ruthenium, indium, nickel, and aluminum, or a mixture or alloy of two or more thereof. Mirror ink. 3. The mirror ink according to claim 1, wherein the metal fine particles are coated with a dispersant which is one or a mixture of two or more selected from amines, alcohols, phenols and thiols. . 4. The mirror ink according to claim 1, further comprising a compound that generates an acid component upon irradiation with energy rays. The mirror ink according to claim 4, wherein the compound that generates an acid component upon irradiation with energy rays is one kind selected from an onium compound, a sulfone compound, a halide, and an iron allene complex, or a mixture of two or more thereof. 6. The mirror ink according to claim 5, wherein the energy beam is an electron beam or an ultraviolet ray. A mirror surface printing method comprising: a step of printing the mirror ink according to any one of claims 1 to 6 on a substrate to be printed; a step of irradiating an energy beam onto the substrate to be printed with the mirror ink; and a step of heating at 150 ° C or lower. .