JPWO2016117518A1 - Ink, edible body manufacturing method using the same, and edible body printing method - Google Patents

Abstract

An ink jet ink suitable for marking on the surface of an edible body such as a tablet, capsule or food, having excellent ink droplet ejection from an ink jet printer nozzle, and printing on a substrate. Disclosed is an ink that can be prevented from fading, can be continuously ejected, and has fixing properties to a printing material and light resistance. An ink containing at least (i) a color material, (ii) a dispersion medium, and (iii) a dispersant, wherein the color material is activated carbon.

Description

  The present invention relates to an ink suitable for printing by an inkjet method, particularly for marking the surface of oral products such as tablets, capsules and foods.

  In order to prevent accidental ingestion, counterfeiting, and drug identification, it is common practice to print symbols, letters, numbers and / or patterns on the surface of solid preparations such as tablets, hard capsules, and soft capsules. Yes.

Conventionally, printing on the surface of these solid preparations has been performed by a plate-making method such as offset printing or gravure printing. For example, Patent Literature 1, Patent Literature 2, and Patent Literature 3 describe a method of transferring ink to a printing material in a stamp type by pressing a rubber roll surface against a printed material such as a tablet.
However, these plate-based methods are based on the premise that the printing surface has a certain degree of hardness, and that the surface is flat and has no irregularities. Satisfactory marking on a wide variety of tablets such as sugar-coated tablets and OD tablets (orally disintegrating tablets) has been difficult.

  Therefore, it is conceivable to employ a non-plate printing method such as an inkjet method or a UV laser method. In particular, according to the ink jet method, the surface to be printed is less restricted than the UV laser method, and printing can be performed on a wider range of objects.

  Inkjet systems are broadly classified into continuous types and on-demand types, and in either method, it is necessary to stably eject ink from thin nozzles. In the continuous type, ink particles ejected continuously are charged as necessary, and deflected in accordance with the amount of charge by a deflection electrode to bend the course and adhere to the print surface. At this time, the uncharged ink particles are collected and returned to the ink tank again. On the other hand, the on-demand type is a system that ejects ink only when necessary. The latter on-demand type has the advantage that the structure of the ink ejection mechanism is simpler and easier to miniaturize than the continuous type, but the ink tends to clog because the ink concentrates or settles while it is not ejected. Therefore, when a pigment is used as the ink coloring material, it is not easy to achieve satisfactory discharge performance and stable performance. In particular, in order to print on an edible body such as a tablet, it is necessary that all the components contained in the ink be ingested into the body, so that a conventionally known inkjet ink is used as it is. It ’s difficult. Here, the pigments that can be used in the edible body are limited, and include lake pigments and inorganic pigments. However, it is difficult to stably disperse these pigments as fine particles in an aqueous medium, and separation or precipitation in the liquid occurs over time, which induces clogging of the ink nozzles and is difficult to use for ink. It is. Further, in the case of a printing material such as a tablet, since the surface thereof may be coated, satisfactory adhesion with an ink component is often not obtained. Furthermore, when selecting the material for the surface of the substrate, there are restrictions such as being edible, not inhibiting the effective expression of the active ingredients of the tablet, and having sufficient adhesion with the ink without problems. is there.

On the other hand, when a dye is used as the coloring material, there is a problem that satisfactory light resistance and water resistance cannot be obtained.
Patent Document 4 describes an ink formed by dispersing charcoal pigment and shellac resin or cellulose resin. However, since the upper limit of the pigment concentration in the ink is 0.7% by weight, it seems that the printing contrast (colorability) cannot be sufficiently ensured. Further, it is disclosed that it is used for continuous ink jet, and it is estimated that it is difficult to prevent nozzle clogging when used for on-demand ink jet.

JP 2000-42089 A JP 2000-229847 A JP 2001-31898 A WO2014 / 014010A1 publication

  An object of the present invention is to provide an ink that can be used for marking on the surface of an edible body such as a tablet, a capsule, or a part of food, and is also suitable for printing by an inkjet method.

  Therefore, as a result of intensive studies to achieve the above-mentioned object, the present inventors can use a specific color material, add a specific polymer material or adjust the dispersed particle size as appropriate, and can be taken in the body. An excellent ink that has excellent adhesion to the tablet surface with only the components, and has sufficient fixability and light resistance while enabling continuous ejection even in ink jet printing, and exhibits sufficient colorability. And completed the present invention.

That is, the present invention
(1) An ink containing at least (i) a color material, (ii) a dispersion medium, and (iii) a dispersant, wherein the color material is activated carbon,
(2) An ink containing at least (i) a color material and (ii) a dispersion medium, wherein the color material is activated carbon, and an average dispersed particle diameter of the activated carbon in the ink is 50 nm to 1 μm. Ink,
(3) The ink according to (1) or (2), wherein the dispersion medium contains one or more of ethanol, isopropanol, polyethylene glycol, propylene glycol, and glycerin,
(4) The ink according to any one of (1) to (3), having a viscosity of 1.0 to 10.0 mPa · s and a surface tension of 30 to 38 mN / m,

(5) The ink according to any one of (1) to (4) above, which is an inkjet ink,
(6) The ink according to any one of (1) to (5), which is used as a marking ink on the surface of an orally ingested product,
(7) A method for producing an orally ingested product, wherein the ink according to any one of (1) to (6) is printed on a printing surface using an inkjet printing apparatus, and (8) the above ( A printing method comprising printing the ink according to any one of 1) to (6) on an orally ingested product using an inkjet printing apparatus.

  According to the present invention, with only components that can be taken in the body, it has excellent adhesion to the tablet surface in particular, and can be continuously ejected even in printing by an ink jet method while maintaining adhesion, water resistance, light resistance, and faintness. An excellent ink having a sufficient colorability can be obtained.

  The ink of the present invention is characterized by containing at least (i) a color material and (ii) a dispersion medium, and using activated carbon as the color material.

[Activated carbon]
Activated carbon is a black porous powder, and is generally used for deodorization, water purification, wastewater treatment, catalyst support, and the like using its pores. In particular, purified activated carbon is used as medicinal charcoal and is used to adsorb gas and toxic substances in the intestines and discharge them outside the body. In the present invention, activated carbon, which is not common as a color material, is used as a black color material.
Activated carbon is known as a carbon material having a very large specific surface area. By heating carbon materials such as wood, so-called charcoal such as Bincho charcoal is obtained (this process is called “carbonization”), but the specific surface area of charcoal (including powdered ones) is generally 300-500 m ² / g. On the other hand, activated carbon is one that has reached 800 to 2000 m ² / g and further 500 to 3000 m ² / g by treating charcoal at a high temperature close to 1000 ° C. (In this way, the carbon material is treated at a high temperature. (It is called “activation” or “activation reaction”) that the specific surface area is increased to become activated carbon, which is known to have extremely high adsorption performance.

In general, activated carbon is made by reacting with a gas or a chemical at a high temperature using a carbon material such as coal or coconut shell as a raw material. There are known a chemical activation method in which a raw material is impregnated with a zinc chloride solution and heated under certain conditions, and a water vapor activation method in which the raw material and heated water vapor are activated at a temperature of 800 to 1000 ° C. The production method is not particularly limited.
Activated carbon is roughly classified into three types, that is, “coal-based”, “plant-based”, and “others” depending on the raw material, but can be used without any particular limitation in the present invention.

  Moreover, it can be roughly divided into powdered activated carbon and granular activated carbon depending on the shape. Powdered activated carbon refers to powder having a particle size that passes through a sieve of 100 mesh (aperture 0.15 mm), and granular activated carbon refers to that having a particle size that does not pass through the sieve. Other special shapes include fibrous activated carbon and specially-shaped activated carbon (honeycomb shape, plate shape (sheet shape)). In the present invention, it is preferable to use powdered activated carbon because it is finer and excellent in dispersibility and colorability.

Although the physical property of the activated carbon used by this invention is not specifically limited, Generally, an average particle diameter is 1-100 micrometers, Most preferably, it is a 5-70 micrometers thing.
The specific surface area is not particularly limited, but is preferably 500 to 3000 m ² / g, particularly preferably 1000 to 2000 m ² / g.
The total pore volume is not particularly limited, but is preferably 0.3 to 5 ml / g, more preferably 0.5 to 4 ml / g, and most preferably 0.5 to 3 ml / g.

The average pore diameter is preferably 1 to 20 nm, particularly preferably 2 to 10 nm.
The pH of the activated carbon is preferably 3 to 8, particularly preferably 4.5 to 7.5.
The iron content in the activated carbon is preferably 0.03% by weight or less, particularly preferably 0.01% by weight or less.
Measurement of pH, average particle diameter, specific surface area, total pore volume, average pore diameter, and iron content is based on the method of JIS K 1474-91.

Also, the activated carbon used in the present invention, according to the method described in JIS K 1474-91 and food additives compendia, chloride 0.53% or less (as Cl), (as SO ₄₎ sulfate 0. What is 48% or less, zinc 0.10% or less, and arsenic (as As ₂ O ₃ ) 4.0 μg / g or less is preferable.
If it is in these ranges, since it conforms to the food additive standards, printing on the edible body is possible, and the influence of the impurities on the ink physical properties can be prevented.

The amount of the activated carbon is 0.1 to 10% by weight, preferably 0.5 to 8% by weight, more preferably 1 to 5% by weight in the ink liquid.
If it is less than 0.1% by weight, the concentration as a colorant is thin, and the marking performance of the object may not be sufficient. If it exceeds 10% by weight, it may be difficult to achieve continuous ejection due to poor temporal stability of the ink due to agglomeration of activated carbon, and further, the ejection performance from the nozzles decreases.

As described above, the activated carbon is a black powder or a granular material, but is not usually used as a coloring material. This is because in normal usage, the degree of blackness is not high and the dispersibility is not high. In contrast, in the present invention, surprisingly, the activated carbon is converted into an ink as a color material, thereby achieving sufficient coloring, achieving stable and fine dispersion applicable to inkjet printing, and also for oral administration. It can be used safely.
Further, in the present invention, by using activated carbon and a dispersant described later, the above-described 0.1 wt% to 10 wt%, particularly 0.5 wt% to 8 wt%, and further 1 wt% to 5 wt% Since it can be contained in the ink at a high concentration and a stable dispersed state can be maintained, it can also be used for a continuous ink jet printer.

  First of all, we were able to obtain such an excellent ink, even if it is a material that is not normally used as a coloring material. This is largely due to the extensive study by the present inventors. In addition, the affinity between activated carbon and the surface of tablets and other edible bodies, which has not been a target of inkjet printing, is excellent. In particular, excellent ink performance could be obtained by being present in the ink in the finely dispersed state described below.

[Dispersant]
The ink of the present invention is an ink containing at least (i) a color material, (ii) a dispersion medium, and (iii) a dispersant, wherein the color material is activated carbon.
In general, in order to prepare a liquid composition in which solid fine particles such as pigments are dispersed in a liquid medium, a compound called a dispersant is added. These are general terms for surfactants that have the function of stably dispersing solid fine particles such as pigments in a dispersion medium. In general, these surfactants have a relatively low molecular weight and generally several hundred to several thousand molecular weights. It is roughly classified into a compound called an agent (amphiphile) and a polymer dispersant having a higher molecular weight and consisting of an oligomer or a polymer.

The surfactant is composed of a hydrophilic part composed of a functional group highly compatible with water and a hydrophobic part that is easily compatible with oil. Surfactants are roughly classified into nonionic surfactants, anionic surfactants, cationic surfactants, and zwitterionic surfactants depending on the type of ions.
Specifically, examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, fatty acid monoglyceride, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid. Examples include esters, glycerin fatty acid esters, and polyoxyethylene-added acetylene glycol.
Examples of the anionic surfactant include alkylbenzene sulfonate, higher alcohol sulfate ester salt, higher fatty acid salt, higher alkyl dicarboxylate, alkyl naphthalene sulfonate, alkyl sulfosuccinate, naphthalene sulfonate formalin condensate salt, poly Examples thereof include oxyethylene alkyl ether sulfates and polyoxyethylene alkyl phosphate esters.
Examples of the cationic surfactant include aliphatic amine salts, aliphatic phosphonium salts, and aliphatic sulfonium salts.
Zwitterionic surfactants are those having a group imparting cationicity and a group imparting anionicity, the ionicity of which varies with pH. For example, N-alkylaminopropionic acid, dimethylalkylamine oxide, N-alkyl Examples include betaine, alkylbetaine, N-alkylsulfobetaine and the like.

Polymeric dispersants are generally roughly classified into water-soluble resins and self-emulsifiable resins.
As adsorbing groups to the solid fine particles, basic groups such as isocyanate groups, epoxy groups, amides and amines, and acidic groups such as carboxy groups and phosphoric acid groups are common.
A type that has many hydrophilic groups in the molecular chain, in which water molecules hydrate and dissolve, and the adsorbing groups on the solid particles are neutralized with sodium, potassium, ammonium, etc. to become neutralized salts There are types that exhibit solubility, and types that self-emulsify by the hydrophilic group of the monomer.

There are various types of resin of the polymer dispersant, and for example, acrylic resin, urethane resin, epoxy resin, polyester resin, etc. are common.
The polymer dispersant used in the present invention is preferably an acrylic resin or a urethane resin excellent in dispersibility and fixability.
As the acrylic resin, styrene-acrylic acid copolymer, styrene-methylstyrene-acrylic acid copolymer, styrene-acrylic acid- (meth) acrylic acid ester (lower alkyl ester of about C1 to C4, the same shall apply hereinafter) Polymer, methacrylic acid- (meth) acrylic acid ester copolymer, acrylic acid- (meth) acrylic acid ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid copolymer, styrene- (meth) acrylic Acid ester-maleic acid copolymer, styrene- (meth) acrylic acid ester-allylsulfonic acid copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer, or sodium, potassium thereof, Salts such as ammonium, carboxyvinyl polymer, polyax Such as Le sodium and the like. Other modified types are also included.

  These dispersants can be used without particular limitation. Furthermore, any compound that has an affinity for activated carbon and has a function of stabilizing activated carbon in a liquid medium can be used without particular limitation to those known as dispersants.

  Among these various types of dispersants, polymer dispersants are particularly suitable for the ink containing the activated carbon of the present invention. The polymer dispersant can be synthesized by a known method, but a commercially available product may be used. Examples of such commercially available products include the following.

  Commercially available polymer dispersants that are acrylic resins include Jonkrill 61J and Jonkrill 62 as aqueous solution types, and Jonkrill 67, Jonkrill 678, and Jonkrill 586 as flaky types used by neutralization and dissolution. , Jonkrill 680, Jonkrill 683, Jonkrill 690, etc. (above are trade names of products manufactured by BASF); BYK-154, DISPERBYK190, DISPERBYK191, DISPERBYK2010, DISPERBYK2015, etc. Name).

Examples of commercially available polymer dispersants that are urethane resins include Neoretz R-9320, Neorad R-440 (the above are trade names of products manufactured by AstraZeneca Co., Ltd.); Iselux S-1020, Iselux S-1020, IZELUX S-1040 (above are trade names of products manufactured by Hodogaya Chemical Co., Ltd.); Bamboo rack W-5025, Bamboo rack 5030, Bamboo rack W-5661, Bamboo rack W-6010, Bamboo rack W-6020, Bamboo rack W-6061, Bamboo rack W-6110, Bamboo Rack W-405, Bamboo Rack W-605, Bamboo Rack WS-4000, Bamboo Rack WS-5000, Bamboo Rack WS-5100, Bamboo Rack WS-5984, Bamboo Rack WS-6021, Bamboo Rack WSA-5920, etc. Made by company Goods of the trade name); HYDRAN ADS-110, HYDRAN ADS-120, HYDRAN CP-7050, such as HYDRAN 7610 (more than the trade names of products manufactured by DIC Co., Ltd.) and the like.
Specific examples of the epoxy resin include W2801, W2821R70 (the above are trade names of products manufactured by Mitsubishi Chemical Corporation); SR-PG, SR-2EG and the like (the above are the trade names of products manufactured by Sakamoto Pharmaceutical Co., Ltd.).

  The weight average molecular weight of the polymeric dispersant is preferably 1,000 to 100,000. More preferably, it is 1,000-80,000, Especially preferably, it is 1,500-50,000, Most preferably, it is 2,000-30,000.

  The weight average molecular weight of the dispersant is measured by GPC method (Gel Permeation Chromatography). It is the most widely used method for measuring the molecular weight of polymers, and is the SEC method (Size Exclusion Chromatography). Size exclusion chromatography), or one of liquid chromatography also called GFC method (Gel Filtration Chromatography). In general, a calibration curve (also referred to as “calibration curve”) showing the relationship between the elution time and the molecular weight is obtained and calculated in advance using a standard polymer such as polystyrene.

In this invention, what was measured on condition of the following is used.
GPC measuring device: In a GPC system manufactured by Shimadzu Corporation, a detector having an RI detector and a PDA detector is used as a detector, and detection is performed by an RI detector.
column:
Guard column “SuperHZ-L” manufactured by Tosoh Corporation (inner diameter 4.6 mm × 2 cm) + “TSKgel SuperHZ4000” manufactured by Tosoh Corporation (inner diameter 4.6 mm × 15 cm)
+ Tosoh Corporation “TSKgel SuperHZ3000” (inner diameter 4.6 mm × 15 cm)
+ "TSKgel SuperHZ2000" manufactured by Tosoh Corporation (inner diameter 4.6 mm x 15 cm)
+ Tosoh Corporation “TSKgel SuperHZ1000” (inner diameter 4.6 mm × 15 cm)
Flow rate 0.35 ml / min Column temperature: 40 ° C
Sample injection volume: Sample; 10 μl, standard product: 100 μl
Sample: 0.5 mass% tetrahydrofuran (THF) solution in terms of resin solid content, filtered through a microfilter (10 μl).
Calibration curve: A calibration curve was obtained using monodisperse standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) with a molecular weight of 4000000-250.
The column type is appropriately selected in consideration of the resolution, molecular weight fraction range, linearity of calibration curve, adsorptivity, recovery rate, solvent exchangeability, column life, sample loading, system dead volume, etc. It is desirable to do.
Also, other methods can be used as long as equivalent results can be obtained.

  The polymer dispersant having the above preferred molecular weight can be synthesized by a known method, but a commercially available product may be selected and used. Among the commercially available products in the most preferred molecular weight range, among them, Jonkrill 61J, Jonkrill 62, Jonkrill 67, Jonkrill 678, Jonkrill 586, Jonkrill 680, Jonkrill 683, Jonkrill 690BYK-154, DISPERBYK190, DISPERBYK191, DISPERBYK2010, DISPERBYK2015 are mentioned.

  The addition amount of the dispersant is preferably 10 to 200 parts by weight, more preferably 15 to 180 parts by weight, and most preferably 20 to 150 parts by weight with respect to 100 parts by weight of the activated carbon. If it is less than 10% by weight, it is difficult to sufficiently disperse the coloring material, and the dispersed particle diameter of the activated carbon in the dispersion medium becomes large. When it exceeds 200 parts by weight, the viscosity of the ink becomes high, and it becomes difficult to eject from the nozzle, and the continuous ejection property is lowered.

  In the ink of the present invention, it has been found that by adding the above-described dispersant, the activated carbon can be stably and finely dispersed and can be suitably used for inkjet printing. In addition, by blending this specific water-soluble polymer, the activated carbon color tone is excellent, the adhesion when printed on various printing objects such as tablets is improved, and the fixing to the printing object is good. Excellent black printing became possible without rubbing and disappearing. The mechanism for obtaining such an excellent effect is not completely clear, but it has good affinity with activated carbon, which is a porous fine powder, and is stabilized by the interaction with the polarity of the surface of the activated carbon. Guessed. At the same time, it is presumed that it has excellent affinity with the coating components on the surface of tablets and the like.

[Dispersion medium]
The dispersion medium of the present invention is not particularly limited as long as it is a liquid that can disperse activated carbon, and may be appropriately selected according to the application. However, by using water as a main component, in terms of safety and operability. An excellent ink can be obtained. The ink of the present invention can maintain stable dispersibility and continuous discharge in ink jet printing even when water is mainly used as a dispersion medium. When used for printing pharmaceutical edible bodies such as tablets, distilled water and water for injection are suitable. Here, “mainly comprising water” means that 50% by weight or more, more preferably 60% by weight or more of the liquid constituting the ink is water. Particularly preferably, the liquid component other than the specific water-soluble organic solvent described below has a composition that is substantially water.

(Water-soluble organic solvent)
In the present invention, it is desirable to include a specific water-soluble organic solvent as a liquid component other than water. When these water-soluble organic solvents are added, the head portion can be prevented from being clogged and the drying property of the ink can be adjusted when the ink-jet printing is used. Specific examples of such water-soluble organic solvents include, for example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, t-butanol, trimethylolpropane, ethylene glycol monoethyl ether, ethylene Glycol monobutyl ether, monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, diglycerin, 1,2-hexane Diol, 1,6-hexanediol, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,5-pentanediol, monoethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, monoethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, triethylene glycol dimethyl ether, triethylene glycol monobutyl ether, methyl lactate, lactic acid It is selected from ethyl and 1,3-dimethyl-2-imidazolidinone, and these can be used alone or in admixture of two or more. Particularly preferably, ethanol, isopropanol, polyethylene glycol, propylene glycol, glycerin and the like are suitable as food additives.

  The addition amount of the water-soluble organic solvent is 5% to 30% by weight, preferably 6% to 25% by weight in the ink liquid, and if added more than that, the ink itself has a high viscosity, and the stability of the ink is increased. In addition, the dischargeability from the nozzle and the nozzle may be reduced, and the drying speed may be reduced. Addition of less than 5% by weight may cause a problem in nozzle discharge, resulting in blurring and continuous discharge.

[Surface tension modifier]
In the present invention, a surface tension adjusting agent can be used as necessary. The surface tension adjusting agent is a component having the function of improving the discharge from the nozzle and adjusting the surface tension.
Specific examples of the surface tension adjusting agent include surfactants such as nonions and anions. Specifically, for example, alkylbenzene sulfonates, higher alcohol sulfates, higher fatty acid salts, higher alkyl dicarboxylates, alkyls. Anionic surfactants such as naphthalene sulfonate, alkyl sulfosuccinate, naphthalene sulfonate formalin condensate salt, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phosphate ester; for example, polyoxyethylene alkyl ether, polyoxy Ethylene alkyl phenyl ether, fatty acid monoglyceride, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, glycerin fatty acid ester Ether, nonionic surfactants such as polyoxyethylene-added acetylene glycol, silicone surfactants, fluorine surfactants, ethanol, water-soluble organic solvent such as isopropanol and the like.

In the ink of the present invention, nonionic surfactants such as sucrose fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, glycerin fatty acid ester, and polyoxyethylene-added acetylene glycol are particularly suitable. Sucrose fatty acid esters such as sugar monostearate and sucrose oligoesters and glycerin fatty acid esters such as triacetin can achieve the most preferable liquid properties.
The addition amount of the surface tension adjusting agent may be appropriately selected according to the required surface tension, but it is preferably 0.5 to 30% by weight, particularly preferably 1 to 20% by weight in the ink.

[Sugar and other additives]
Saccharides can be added for the purpose of improving dischargeability and adhesion. Examples of the sugar include monosaccharides, disaccharides, and polysaccharides.Specific examples include glucose, galactose, mannose, growth, talose, allose, altrose, idose, fructose, sorbose, tagatose, psicose, sucrose, maltose, Lactose, maltotriose, isomaltose, maltotetraose, isomaltotriose, isomalttetraose, panose, nigerose, kojibiose, lactose, palatinose, kestose, nistose, fructosylnystose, inulobiose, inurotriose, inurotetra Examples thereof include aose, isomalterose, maltosyl sucrose, maltotriosyl sucrose, maltopentaose, maltohexaose, maltoheptaose and the like. The sugar derivatives are preferably sugars obtained by reducing or oxidizing the above sugars, and specific examples include maltitol and sorbit.
The addition amount is preferably 1 to 20% by weight in the ink liquid, and has the function of improving the fading when printing on the recording medium and stabilizing the ejection properties.

  Further, in the ink of the present invention, orthophenylphenol, sodium orthophenylphenol, diphenyl, thiabendazole, and imazalil are preferable as the antifungal agent so as to have desired physical properties, and hypochlorite is used as the disinfectant. Sodium acid, hydrogen peroxide and ethanol are preferred. Moreover, additives, such as an antifoamer, a rust preventive agent, and a PH adjuster, can be mix | blended suitably.

In addition, the ink of the present invention is characterized by containing activated carbon as a color material, but other color materials may be contained within a range not impeding the performance of the present invention.
However, sufficient coloring can be obtained with activated carbon alone for edible printing applications described below.

  In addition, for the purpose of adjusting the viscosity of the ink, improving the adhesion, and other purposes, a water-soluble polymer and other components may be appropriately added as long as the performance of the present invention is not impaired. For example, starch type such as guar gum, locust bean gum, agar, methyl starch, gelatin, pullulan, xanthan gum, tragacanth gum, dextrin, casein, water-soluble cellulose derivatives, non-polar water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone You can also

[Preparation of ink]
The activated carbon in the ink of the present invention has an average dispersed particle size of 50 nm to 1 μm, preferably 50 to 800 nm, more preferably 50 to 700 nm, more preferably 50 to 600 nm, still more preferably 50 to 500 nm, still more preferably 100 to 100 nm. It is 450 nm, most preferably 150 to 400 nm. Within this range, the coloring power, dispersion stability, nozzle ejection property, and fixability to the printed material are the most excellent, but the average dispersed particle diameter is in the range of 50 to 500 nm, regardless of the above-mentioned ink jet device or nozzle. Each physical property is extremely excellent.

When the average dispersed particle size is less than 50 nm, aggregation is likely to occur due to van der Waals force between particles, and the temporal stability tends to be lowered. When the average dispersed particle size exceeds 1 μm, the color material is likely to be squad in the liquid, and precipitation may easily occur.
In addition to controlling the average particle diameter, it is preferable to suppress the amount of coarse particles. If 90% or more of all the activated carbon particles in the liquid are adjusted to have a dispersed particle diameter of 1 μm or less, more preferably 500 nm or less, an ink having further excellent physical properties can be obtained. Dispersion treatment may be performed until the size of all particles falls within this range, but the dispersion treatment is performed until the average particle diameter falls within the above range in order to prevent a large amount of particles that are too fine from being generated and reaggregated. A method of removing coarse particles by a known method such as centrifugal separation or filter filtration is also suitable.

In addition, the measurement of the average dispersed particle diameter here and the dispersed particle diameter of all the particles is as follows.
Conditioning: Dilute the stock solution with ion-exchanged water so that it enters the defined concentration range.
Measuring instrument: Dynamic light scattering particle size distribution analyzer ("NIKKISO: Microlracwave-EX150")
Measurement time: 120 seconds

Moreover, the viscosity of the ink of the present invention described above is 1.0 to 10.0 mPa · s. Preferably, it is 1.5 to 9.0 mPa · s, and particularly preferably 2.0 to 8.0 mPa · s.
When the viscosity is less than 1.0 mPa · s, a satellite phenomenon may occur or the nozzle may not become droplets. Conversely, when the viscosity exceeds 10.0 mPa · s, a satellite phenomenon may occur or ink droplets may not be formed. The satellite phenomenon refers to small droplets such as dust that are separated from the main droplets of the ejected ink droplets from the head nozzle.

The method for measuring the viscosity is as follows.
Conditioning: Stock solution
Measuring equipment: Conical plate type rotational viscometer (“TVE-20L type” (product number) manufactured by Toki Sangyo Co., Ltd.)
Measurement conditions: 50 rpm
Measurement temperature: 25 ° C

The surface tension is preferably 28 to 40 mN / m, more preferably 30 to 38 mN / m, and particularly preferably 31 to 37 mN / m.
Further, when the surface tension is less than 28 mN / m, a phenomenon occurs in which the liquid droplets are ejected without sufficient droplets, and the same applies when the surface tension exceeds 40 mN / m.

The method for measuring the surface tension is as follows.
Conditioning: Stock solution
Measuring instrument: Automatic surface tension meter (plate method) (Kyowa Interface Science Co., Ltd. “CBVP-Z”)
Measurement temperature: 25 ° C

[Preparation of ink]
The ink of the present invention can be prepared by mixing the above-described components into an ink. The mixing method is not particularly limited. For example, after the activated carbon, the water-soluble polymer, and water are mixed and stirred, the activated carbon is dispersed by a dispersing machine such as a paint shaker, a roll mill, a ball mill, a sand mill, or a jet mill. Can be stabilized in water.

At this stage, the method of removing coarse particles and then adding the water-soluble organic solvent and the surface tension adjusting agent described above to form an ink is also suitable for ensuring a stable and good dispersion state.
Alternatively, it is possible to further improve the quality by subjecting the prepared ink to filter processing or the like by a known technique, or removing impurity ions.

[Printing method and application]
Printing can be performed on various objects using the ink of the present invention described above. Since the ink of the present invention can be prepared with only components that can be safely taken into the body, it can be suitably used for printing on pharmaceuticals such as tablets and capsules or printing on various foods. The printing method is not limited, and it may be used for offset printing and gravure printing methods that have been used for edible printing conventionally, but even when used for inkjet printing, it maintains stable ejection properties and is excellent. Performance can be demonstrated. That is, it can be used as an inkjet ink for printing using an inkjet printer, and can also be used as a marking ink on the surface of an edible body. The ink of the present invention is printed using an inkjet printer. An edible body can be produced by printing on the surface.
Since the printed matter obtained in this way is excellent in colorability and fixability, the ink of the present invention is used for various purposes such as prevention of counterfeiting, ensuring traceability, preventing accidental ingestion, improving discrimination, and imparting amusement properties. Printing on medicines, foods, etc. can be performed.

  Hereinafter, the present invention will be described in detail with reference to examples. In the examples, all “parts” indicate parts by weight, and “%” indicates all parts by weight.

[Example 1]
The following components were blended and stirred for 1 hour at room temperature with a propeller stirrer.

Component amount
(Parts by weight (hereinafter referred to as parts))
Activated carbon 10.0
(Average particle diameter: 25 μm, average pore diameter: 2.8 nm)
20% John Krill 683 15.0
TEA 120% neutralization (molecular weight 8000)
Water 75.0

Next, 150 g of 0.7 mm-diameter glass beads were put into a paint shaker pot and shaken for 3 hours.
Coarse particles contained in this dispersion are removed to adjust the dispersion particle diameter of 90% or more of all the particles to 500 nm or less and the solid content concentration to 10% by weight to obtain “Dispersion 1”. Ink formation was performed by the following method.

Component amount (parts)
Dispersion 1 (solid content 10%) 50.0
Glycerin 10.0
Ethanol 10.0
Fatty acid monoglyceride 3.0
Water 27.0
The mixture was stirred for 30 minutes to prepare an ink.
The obtained ink had an average dispersed particle size of 297 nm, a viscosity of 2.8 mPa · s, and a surface tension of 33 mN / m.
Furthermore, the above inks were examined for stability over time, ejection properties, fixing properties, light resistance, and water resistance according to the following methods. The results are shown in Table 1.

(A) Stability test over time The ink was put in a glass bottle and allowed to stand in a thermostatic chamber at 5 ° C. for 1 month, and then the presence or absence of color material separation, water floating and sedimentation was confirmed. The state in which separation of the coloring material, water floating and sedimentation occurred as little as possible was evaluated as abnormal.
In Table 1, “O” indicates no abnormality and “X” indicates abnormality.

(B) Ejectability test Using an inkjet printer (Qualicaps Co., Ltd.) and a droplet observation device, whether or not ink can be ejected from the head, whether or not droplets can be formed, and whether or not re-ejection can be performed after ejection has been stopped Was investigated.

(C) Fixability drying test Using a tablet immediately after printing with an ink jet printer as a sample, the printed portion of the sample was rubbed with a nonwoven fabric, and the presence or absence of ink extension and the presence or absence of ink transfer to the nonwoven fabric were investigated.

(D) Light resistance test About 0.5 mL of ink was applied to white paper for color tone test using a bar coater No. 5, and the ink was dried to prepare a sample for light resistance test. Place the sample in a light stability tester (LST-300D manufactured by Tokyo Rika Kikai Co., Ltd.), and after exposure at a total illuminance of 1.2 million lux · hr, the sample before exposure using visual and spectral color difference meter (SE6000 manufactured by Nippon Denshoku Industries) The difference in color tone was investigated.

(E) Water resistance test A tablet having a wire diameter of about 0.1 mm and a size of about 0.5 mm square was printed on a tablet by an ink jet printer to prepare a sample for water resistance test. A sample was stored in a desiccator with a saturated solution of sodium chloride and kept in a constant humidity state (relative humidity of about 75%) for 1 week, and then the presence or absence of bleeding on the printed portion was examined.
(F) Coloring test The printed part of the sample after the test prepared in the test of (e) was visually confirmed to confirm whether the printing can be distinguished and the color tone. Black or dark gray (red when red color material is used) that can be clearly distinguished is marked with ◯, and others with x.

[Comparative Example 1]
Ink was produced in the same manner as in Example 1, except that the activated carbon was replaced with a petal.
[Comparative Example 2]
Ink was produced in the same manner as in Example 1, except that the activated carbon was replaced with black iron oxide.

[Example 2]
The following components were blended and stirred for 1 hour at room temperature with a propeller stirrer.

Component amount Activated carbon 10.0
(Average particle size: 30 μm, average pore diameter: 2.1 nm)
20% Jonkrill 678 15.0
TEA 120% neutralization (molecular weight 8500)
Water 75.0

Next, 150 g of 0.7 mm diameter glass beads were put into a paint shaker pot and shaken for 3 hours.
Coarse particles contained in this dispersion are removed and adjusted so that the dispersion particle diameter of 90% or more of all particles is 500 nm or less and the solid content concentration is 10% by weight to obtain “dispersion 2”. Ink was obtained by the following method.

Component amount (parts)
Dispersion 2 (solid content 10%) 50.0
Glycerin 10.0
Propylene glycol 10.0
Sucrose fatty acid ester 10.0
Water 20.0
The mixture was stirred for 30 minutes to prepare an ink.
The obtained ink had an average dispersed particle size of 320 nm, a viscosity of 2.3 mPa · s, and a surface tension of 32 mN / m.

[Comparative Example 3]
Ink was prepared in the same manner as in Example 2, except that the activated carbon was replaced with a water-soluble black dye.

[Example 3]
The following components were blended and stirred for 1 hour at room temperature with a propeller stirrer.

Component amount Activated carbon 10.0
(Average particle diameter: 35 μm, average pore diameter: 3.4 nm)
20% Jonkrill 690 15.0
TEA 200% neutralization (molecular weight 16500)
Water 75.0

Next, 370 g of 0.5 mm-diameter zirconia beads were placed in a paint shaker pot and shaken for 5 hours.
Coarse particles contained in this dispersion are removed and adjusted so that the dispersed particle diameter of 90% or more of all particles is 500 nm or less and the solid content concentration is 10% by weight to obtain “dispersion 3”. The following ink was made.

Component amount (parts)
Dispersion 3 (solid content 10%) 48.0
Sucrose fatty acid ester 10.9
Water 41.1

The mixture was stirred for 30 minutes to prepare an ink.
The obtained ink had an average dispersed particle size of 397 nm, a viscosity of 4.3 mPa · s, and a surface tension of 32 mN / m.

[Comparative Example 4]
In Example 4, except that the activated carbon was replaced with Bincho charcoal, an ink was prepared in the same manner, but when the mixture was put into a propeller stirrer and stirred, it was vigorously thickened and gelled, and lost its fluidity. Since no ink was formed, none of the tests could be performed.

なお比較例１及び比較例２では、吐出性が悪くインクジェット印刷機による印字が困難であり、耐水性試験のための試料を作成できなかった。また、比較例３では、耐水性試験の実施により、錠剤に印字された文字が滲んでしまい、発色試験においては文字の判別が困難で、また印字の濃度も薄くなっていた。

In Comparative Example 1 and Comparative Example 2, it was difficult to print with an ink jet printer due to poor dischargeability, and it was not possible to prepare a sample for a water resistance test. Further, in Comparative Example 3, the characters printed on the tablets were blurred due to the water resistance test, and it was difficult to distinguish the characters in the color development test, and the printing density was low.

  From the above Examples and Comparative Examples, it can be seen that the ink of the present invention using activated carbon as a coloring material and containing a dispersant has excellent characteristics as an inkjet ink.

  According to the present invention, it has excellent fixability on the tablet surface only with components that can be ingested by the body, and it enables fixing and light fastness while enabling continuous discharge even in ink jet printing, particularly on-demand printing. An excellent ink provided, a printing method using the ink, and a method for producing an edible body can be provided.

Claims (8)

  An ink comprising at least (i) a color material, (ii) a dispersion medium, and (iii) a dispersant, wherein the color material is activated carbon.   An ink comprising at least (i) a color material and (ii) a dispersion medium, wherein the color material is activated carbon, and an average dispersed particle diameter of the activated carbon in the ink is 50 nm to 1 μm.   The ink according to claim 1 or 2, wherein the dispersion medium contains one or more of ethanol, isopropanol, polyethylene glycol, propylene glycol, and glycerin.   The ink according to any one of claims 1 to 3, which has a viscosity of 1.0 to 10.0 mPa · s and a surface tension of 30 to 38 mN / m.   The ink according to claim 1, which is an ink jet ink.   The ink according to any one of claims 1 to 5, which is used as a marking ink on the surface of an edible body.   A method for producing an edible body, wherein the ink according to any one of claims 1 to 6 is printed on a printing surface using an ink jet printing apparatus.   A printing method comprising printing the ink according to any one of claims 1 to 5 on an orally ingested product by an ink jet printing apparatus.