JP6530769B2 - Ink, method for producing edible body using the same, and printing method for edible body - Google Patents

Description

  The present invention relates to an ink suitable for ink jet printing, in particular for marking the surface of oral products such as tablets, capsules, foods and the like.

  It is a common practice to print symbols, letters, numbers and / or patterns on the surface of solid preparations such as tablets, hard capsules, soft capsules etc. to prevent accidental ingestion, forgery prevention, drug identification etc. There is.

Conventionally, printing of the solid preparation surface is performed by a plate method such as offset printing or gravure printing. For example, Patent Document 1, Patent Document 2, and Patent Document 3 describe a method of transferring ink to a printing material in a stamp type by pressing the rubber roll surface against a printed material such as a tablet.
However, these plate 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 unevenness, so an uncoated tablet not necessarily having these characteristics, Satisfactory marking on a wide variety of tablets such as sugar coated tablets and OD tablets (orally disintegrating tablets) has not been easy.

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

  The ink jet method is roughly classified into a continuous type and an on-demand type, and in any method, it is necessary to stably discharge the ink from a thin nozzle. In the continuous type, the ink particles which are continuously jetted are charged as necessary, and the path is bent to be attached to the printing surface by deflecting the ink particles according to the charge amount by the deflection electrode. At this time, the ink particles not charged are collected and returned to the ink tank again. On the other hand, the on-demand type is a method of discharging 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 is concentrated or sedimented during ejection and the nozzle is easily clogged. Since there is a problem that it is not easy to achieve satisfactory ejection performance and stability of performance when a pigment is used as a coloring material of ink. In particular, in order to print on an edible substance such as a tablet, it is necessary that there is no problem even if all the components contained in the ink are ingested into the body, and the conventionally known inkjet ink is used as it is Things are difficult. Here, the pigment which can be used for the edible material is limited, and lake pigments, inorganic pigments and the like can be mentioned. However, it is difficult to stably disperse these pigments in the form of fine particles in an aqueous medium, and separation or precipitation in the liquid occurs over time, which causes clogging of the ink nozzle, making it difficult to use for the ink It is. Moreover, in the case of a substrate such as a tablet, since the surface may be coated, satisfactory adhesion with the ink component can not often be obtained. Furthermore, when selecting the material of the surface of the printing material, there are limitations such as being edible, not inhibiting the expression of the effect of the active ingredient of the tablet, and sufficiently adhering without problems in affinity with the ink. is there.

On the other hand, when a dye is used as a coloring material, there is a problem that satisfactory light resistance and water resistance can not be obtained.
Patent Document 4 describes an ink obtained by dispersing carbon black pigment with a shellac resin or a cellulose-based resin. However, since the upper limit of the pigment concentration in the ink is about 0.7% by weight, it is considered that sufficient printing contrast (colorability) can not be secured. In addition, it is disclosed to use for continuous type ink jet, and it is presumed that it is difficult to prevent the occurrence of nozzle clogging when used for on demand type ink jet.

JP 2000-42089 A JP 2000-229847 A JP 2001-31898 A WO 2014/014010 A1 Publication

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

  Therefore, as a result of intensive investigations to achieve the above object, the present inventors can use the specific coloring material, appropriately add a specific polymer material, and adjust the dispersed particle diameter, thereby being able to be taken in the body. Excellent ink that has excellent adhesion to the tablet surface, in particular, and is capable of continuous discharge even in ink jet printing while providing fixability and light resistance and exhibiting sufficient colorability using only the components The present invention has been accomplished.

That is, the present invention
(1) An ink containing at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a viscosity average molecular weight of 1,000 to 220,000, wherein the colorant is activated carbon Ink, which is characterized by
(2) An ink containing at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a K value of 10 to 90, wherein the colorant is activated carbon ink,
(3) an ink containing at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a number average molecular weight (Mn) of 2,000 to 140,000, wherein the colorant is Ink characterized by being activated carbon,
(4) an ink containing at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a weight average molecular weight (Mw) of 4,000 to 500,000, wherein the colorant is Ink characterized by being activated carbon,
(5) An ink containing at least (i) a coloring material, (ii) a dispersion medium, and (iii) a water-soluble polymer having an average molecular weight (Mz) of 10,000 to 1,000,000, wherein the color is Ink characterized in that the material is activated carbon,
(6) An ink containing at least (i) a coloring material and (ii) a dispersion medium, wherein the coloring material is activated carbon, and the average dispersed particle diameter of the activated carbon in the ink is 50 nm to 1 μm. The ink to be
(7) The ink according to any one of the above (1) to (6), wherein the dispersion medium contains one or more of ethanol, isopropanol, polyethylene glycol, propylene glycol and glycerin.
(8) The ink according to any one of (1) to (7), wherein the viscosity is 1.0 to 10.0 mPa · s, and the surface tension is 30 to 38 mN / m.

(9) The ink according to any one of the above (1) to (8), which is an ink jet ink
(10) The ink according to any one of (1) to (9), which is used for marking ink on the surface of an orally ingested product,
(11) A method for producing an orally-ingested product, characterized in that the ink according to any one of the above (1) to (10) is printed on a printing surface using an inkjet printing apparatus, and (12) the above ((12) 1) to a printing method characterized by printing the ink according to any one of (1) to (10) on an orally ingested product using an ink jet printing apparatus.

  According to the present invention, only ingredients that can be ingested in the body have excellent adhesion to the tablet surface in particular, and adhesion and water resistance, light resistance and scratch resistance while making continuous discharge possible even in printing by inkjet method It is possible to obtain an excellent ink with excellent colorability.

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

[Activated carbon]
Activated carbon is a black porous powder and is generally used for deodorization, water purification, waste water treatment, catalyst loading and the like by utilizing its pores. In particular, purified activated carbon is taken as medicinal charcoal and used to adsorb the gas and toxic substances in the intestine and discharge it from the body. In the present invention, thus, activated carbon which is not general as a coloring material is used as a black coloring material.
Activated carbon is known as a carbon material having a very large specific surface area. By heating a carbon material such as wood, so-called charcoal such as Bincho charcoal is obtained (this process is referred to as "carbonization"), but the specific surface area of charcoal (including powdered one) is generally It is said to be 300 to 500 m ² / g. By contrast, activated carbon, by treating at a high temperature even closer 1000 ° C. charcoal, carbon materials (in this way that a specific surface area of 800~2000m ² / g, yet reached 500~3000m ² / g The fact that the specific surface area is increased by treatment at a high temperature to become activated carbon is known as "activation" or "activation reaction") and is known to have extremely high adsorption performance.

In general, activated carbon is produced by reacting carbon materials such as coal and coconut husks with gases and chemicals at high temperatures. A chemical activation method is known in which a raw material and a heated steam are activated at a temperature of 800 to 1000 ° C., although a chemical activation method in which heating activation is performed under certain conditions after impregnating a zinc chloride solution into a raw material is known. The manufacturing method is not particularly limited.
Activated carbon is roughly classified into three types, ie, "coal-based", "plant-based" and "other" depending on the raw material, but can be used without particular limitation in the present invention.

  Also, depending on the shape, it can be roughly divided into powdered activated carbon and granular activated carbon. Powdered activated carbon refers to a powder having a particle size that passes through a 100 Mesh (0.15 mm mesh) sieve, and granular activated carbon refers to a particle size that does not pass through the sieve. In addition, there are a fibrous activated carbon and a specially formed activated carbon (honeycomb shape, plate shape (sheet shape)) as a special shape. In the present invention, it is preferable to use powdered activated carbon because it is finer and has excellent dispersibility and colorability.

The physical properties of the activated carbon used in the present invention are not particularly limited, but generally, those having an average particle diameter of 1 to 100 μm, particularly preferably 5 to 70 μm.
The specific surface area is also 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 also 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 mean 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 at most 0.03% by weight, particularly preferably at most 0.01% by weight.
The measurement of pH, average particle diameter, specific surface area, total pore volume, average pore diameter, iron content is according to the method of JIS K 1474-91.

In addition, activated carbon used in the present invention is 0.53% or less of chloride (as Cl) and sulfate (as SO ₄ ) in accordance with the method described in JIS K 1474-91 and Food Additives Official Standards. It is preferable that the content is 48% or less, 0.10% or less of zinc, and 4.0 μg / g or less of arsenic (as As ₂ O ₃ ).
Within these ranges, it is possible to print on edible materials because it conforms to the food additive specification, and it is also possible to prevent the influence of impurities on the ink physical properties.

The content of activated carbon in the ink liquid is desirably 0.1% by weight to 10% by weight, preferably 0.5% by weight to 8% by weight, and more preferably 1% by weight to 5% by weight.
If it is less than 0.1% by weight, the concentration as a coloring agent may be low, and the marking performance of the object may not be sufficient. If it exceeds 10% by weight, it may be difficult to achieve continuous discharge due to a defect in stability of the ink with time due to aggregation of activated carbon and further a decrease in the dischargeability from the nozzle.

As described above, activated carbon is a black powder or granular material, but is not usually used as a coloring material (coloring material). This is because, in normal use, the expression of blackness is not high and the dispersibility is not high. On the other hand, in the present invention, surprisingly, by making activated carbon into ink as a coloring material, sufficient coloring is achieved, stable and fine dispersion applicable to ink jet printing is achieved, and even oral administration is achieved. It can be used safely.
Furthermore, in the present invention, 0.1% by weight to 10% by weight, particularly 0.5% by weight to 8% by weight, of the activated carbon described above is preferably mixed with a specific polymer material described later. Since it can be contained in the ink at a concentration as high as 1% by weight to 5% by weight and can maintain a stable dispersion state, it can also be used for a continuous type ink jet printer.

Could such an excellent ink be obtained, first of all, even if it is a material that is not normally used as a colorant, can it be used for coloring applications by performing proper dispersion without being preoccupied? This is largely because the inventors of the present invention have conducted intensive studies. In addition, the affinity of activated carbon with the surface of tablets and other edible materials that were not conventionally targeted for ink jet printing can be mentioned as a result. In particular, excellent ink performance could be obtained by being present in the ink in a finely dispersed state described later.
Furthermore, it is speculated that the combination of a specific water-soluble polymer and activated carbon described below exhibits high colorability as well as a more excellent stable dispersion state.

[Water-soluble polymer]
The first embodiment of the ink of the present invention is an ink containing at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a viscosity average molecular weight of 1,000 to 220,000. The ink is characterized in that the coloring material is activated carbon. That is, it is characterized by containing a water-soluble polymer having a viscosity average molecular weight of 1,000 to 220,000.
Generally, 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 compounds having a function of stably dispersing solid fine particles such as pigments in a dispersion medium, and roughly classified into compounds having a relatively low molecular weight and called surfactants, and polymer compounds having higher molecular weights. It is divided roughly.

Among these, polymer compounds generally have many hydrophilic groups in the molecular chain, in which the water molecules are hydrated and dissolved, long-chain aminoamides, acrylic acids, polycarboxylic acids and salts thereof, etc. As a main structure, there are basic ones such as amides and amines as an adsorptive group to be adsorbed to solid fine particles, and soluble ones having an acidic group such as a carboxy group and a phosphoric acid group as a neutralization salt.
In contrast to these general solid particle dispersion methods, in the present invention, activated carbon that is a solid particle is a polymer, which is water-soluble and has a viscosity average molecular weight of 1,000 to 220,000. Stable dispersion of It is not particularly limited to what is known as a dispersant.

The viscosity average molecular weight of the water-soluble polymer is 1,000 to 220,000, preferably 2,000 to 100,000, more preferably 5,000 to 100,000, and most preferably 7,000 to 50,000. is there.
The measurement of viscosity average molecular weight is basically based on the method of molecular weight measurement described in Polymer Journal Vol. 38, No. 7, pp. 457-463 (July, 1981). That is, it is the following procedure.

(1) The sample is added to excess acetone for precipitation purification. After repeating this operation twice, it is dried under reduced pressure until the acetone odor disappears.
(2) Make an aqueous solution of the purified sample, and use a Ubbelohde viscometer (water, 120 seconds) to determine the viscosity average molecular weight using the Mark-Kuhn-Houwink equation (Mark-Houwink-Sakurada equation). The coefficients M and α of the Mark-Kuhn-Houwink equation use the ones described in the above-mentioned polymer literature collection.
However, any method may be used as long as the same result can be obtained.

  The numerical value of the molecular weight may fluctuate by about 10% because of the measurement error and the like. Therefore, the upper and lower ranges of about 10% of the numerical range described above may be used. The same applies to the number average molecular weight, the weight average molecular weight, and the z average molecular weight described later.

  The water-soluble polymer used in the present invention is particularly preferably nonionic. The index of polarity is an acid value, and in the present invention, the acid value is preferably 30 mg KOH / g or less, more preferably 20 mg KOH / g or less, still more preferably 5 mg KOH / g or less, most preferably no acid value is detected The value is substantially 0 mg KOH / g). Within this range, particularly, the dispersion performance of activated carbon and the printing characteristics such as water resistance of printed matter are excellent.

The measurement of the acid number is a method in accordance with DIN 53402, more specifically as follows.
(1) Weigh the sample into a 0.9 to 1.3 g beaker.
(2) Add 50 ml of acetone.
(3) Measure with an automatic potentiometric titrator using 0.1 N NaOH aqueous solution. The automatic potentiometric titration device has the same result regardless of which device is used.
(4) The amine value is determined by the following formula.

  Acid value = [(a-b) x 5.61] / E (mg KOH / g)

a: Number of ml of 0.1 N NaOH required for titration b: Number of ml of 0.1 N NaOH required for titration of blank E: Weight of sample (g)
(5) Display: Display up to one decimal place.

  The second form of the ink of the present invention is an ink containing at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a K value of 10 to 90, wherein the colorant is It is an ink characterized by being activated carbon. That is, it is characterized in that it contains a water-soluble polymer having a K value of 10 to 90. The K value of the water-soluble polymer is preferably 10 to 90, particularly 10 to 60. More preferably, it is 15-40. Here, the K value is obtained by measuring the viscosity according to the method of viscosity measurement method 1 method <2.53> in the 16th revision Japanese Pharmacopoeia, and according to the Fikentscher equation according to the method described in the column "K value" described in the pharmacopoeia It is. In this range, particularly, the dispersion performance of the activated carbon and the print characteristics such as the water resistance of the print are excellent. The K value may fluctuate by about 10% because of the measurement error or the like. Therefore, the upper and lower ranges of about 10% of the above value may be used.

  Specifically, casein, a water-soluble cellulose derivative, polyvinyl pyrrolidone, polyvinyl methyl ether and the like are preferably used as the above-mentioned water-soluble polymer depending on the surface material of the printing material.

  As the above-mentioned water-soluble cellulose derivative, a cellulose ether substituted with an alkyl group and a hydroxyalkyl group, or a cellulose ether substituted with a hydroxyalkyl group is suitably used.

  Particularly preferably, non-polar water-soluble polymers such as hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), polyvinyl pyrrolidone and the like are used. These can provide an ink having excellent dispersion stability when used in the ink of the present invention, excellent dischargeability in printing by the ink jet system, and fixing ability to a substrate. Moreover, the affinity with the resin component used as a tablet coating material or a capsule coating material is also excellent. Moreover, it is preferable because an ink having excellent fixability to various objects such as tablets can be obtained.

These water-soluble polymers such as water-soluble cellulose derivatives, polyvinyl alcohol and polyvinyl pyrrolidone have good adhesion to the coating layer of sugar-coated tablets, and can be suitably used for printing sugar-coated tablets by ink jet. Among them, polyvinyl pyrrolidone is mentioned as an example which is excellent in fixing and has a dispersing ability to a coloring material. In particular, polyvinyl pyrrolidone having a viscosity average molecular weight of 1,000 to 220,000 is preferable, one having 2,000 to 100,000 is more preferable, one having 5,000 to 100,000 is more preferable, and 7,000 Those of ~ 50,000 are most preferred.
When the viscosity average molecular weight is less than 2,000, dispersion becomes difficult and the dispersed particle size tends to be large. On the other hand, if it exceeds 220,000, it may be so thick that it may not be possible to obtain a uniform dispersion.

The third embodiment of the ink of the present invention contains at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a number average molecular weight (Mn) of 2,000 to 140,000. An ink, wherein the coloring material is activated carbon. That is, it is characterized in that it contains a water-soluble polymer having a number average molecular weight (Mn) of 2,000 to 140,000.
Preferably, the number average molecular weight (Mn) is 2,500 to 100,000, more preferably 3,000 to 70,000. If it is less than 2,000, dispersion becomes difficult and the dispersed particle size tends to be large. On the other hand, if it exceeds 140,000, it may be so thick that it may not be possible to obtain a uniform dispersion. In particular, 3,000 to 70,000, which is the most excellent in dispersibility, and also excellent in print characteristics such as water resistance of the print.

The fourth embodiment of the ink of the present invention contains at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having a weight average molecular weight (Mw) of 4,000 to 500,000. An ink, wherein the coloring material is activated carbon. That is, it is characterized by containing a water-soluble polymer having a weight average molecular weight (Mw) of 4,000 to 500,000.
Preferably, the weight average molecular weight (Mw) is 8,000 to 400,000, more preferably 10,000 to 200,000. If it is less than 4,000, dispersion becomes difficult and the dispersed particle size tends to be large. On the other hand, when it exceeds 500,000, it is because it may become thick and it may become impossible to obtain a uniform dispersion. In particular, in the range of 10,000 to 200,000, the dispersibility is most excellent, and the print characteristics such as water resistance of the print are also excellent.

The fifth form of the ink of the present invention comprises at least (i) a colorant, (ii) a dispersion medium, and (iii) a water-soluble polymer having az average molecular weight (Mz) of 10,000 to 1,000,000. An ink containing, wherein the coloring material is activated carbon. That is, it is characterized in that it contains a water-soluble polymer having a z-average molecular weight (Mz) of 10,000 to 1,000,000.
Preferably, the z-average molecular weight (Mz) is 20,000 to 600,000, more preferably 30,000 to 300,000. If it is less than 10,000, dispersion becomes difficult and the dispersed particle size tends to be large. On the other hand, if it exceeds 1,000,000, it may be so thick that it may not be possible to obtain a uniform dispersion. In particular, in the range of 30,000 to 300,000, the dispersibility is the best, and the print characteristics such as water resistance of the print are also excellent.

  Here, these number average molecular weight (Mn), weight average molecular weight (Mw), and z average molecular weight (Mz) can be determined by gel permeation chromatography (GPC) as follows. In addition, even if it is another measuring method, as long as an equivalent value can be obtained, it can be used.

Analytical instrument and measurement conditions:
Preparation of sample: 20 mg of sample is weighed, 10 ml of 0.1 M NaNO ₃ / CH ₃ CN (= 80/20) is added, heated and dissolved in a hot air drier at 40 ° C. for 1 hour, and filtered with a 0.45 μm filter Filter and use for measurement.
Preparation of standard product: Weigh 2 mg of sample, add 10 ml of 0.1 M NaNO ₃ / CH ₃ CN (= 80/20), heat to dissolve in a hot air dryer at 40 ° C for 1 hour, and dissolve in a 0.45 μm filter Filter and measure.

GPC measuring device: Shimadzu Corporation main system LC-20AT
Controller CBM-20A
Degasser DGU-12A LC-10
Pump LC-20AP
Column oven CPO-10A
Detector: RI detector (RID detector RID-10A)

column:
TSKgel G3000PWXL (Tosoh) 7.8 mm ID × 300 mm (inner diameter (mm) × length (mm)) Neutral column
TSKgel G6000PWXL (Tosoh) 7.8 mm ID × 300 mm (inner diameter (mm) × length (mm)) Neutral column

Eluent: 0.1 M NaNO ₃ aqueous solution / acetonitrile = 8/2
Flow rate: 1.0 mL / min
Column temperature: 40 ° C
Injection volume: sample; 100μl, standard product; 100μl

  The measurement is performed twice and the average value is adopted.

  The amount of water-soluble polymer added is preferably 20 to 200 parts by weight, more preferably 25 to 180 parts by weight, and most preferably 30 to 150 parts by weight with respect to 100 parts by weight of activated carbon. If it is less than 20% by weight, sufficient dispersion of the colorant is difficult, and the dispersed particle size of the activated carbon in the dispersion medium becomes large. If the amount is more than 200 parts by weight, the viscosity of the ink becomes high, which makes it difficult to discharge the ink from the nozzles, and the continuous dischargeability is reduced.

  It has been found that, in the ink of the present invention, activated carbon can be dispersed stably and finely by blending the specific water-soluble polymer described above, and it can be suitably used for inkjet printing. Moreover, by blending this specific water-soluble polymer, the color tone of the activated carbon is excellent, and the adhesion when printing on a printing object such as various tablets is improved, and the fixing to the printing object is good. It has become possible to print excellent black without rubbing and disappearing. Although the mechanism by which such excellent effects can be obtained is not completely clear, it has a good affinity with the fine powder of activated carbon, which is a fine powder, and is stabilized by the interaction with the polarity of the surface of the activated carbon It is guessed. At the same time, it is also presumed that the affinity with the coating component on the surface of the tablet or the like is excellent.

[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, but by using water as a main component, in terms of safety and operability. It can be an excellent ink. In addition, even when water is used as a dispersion medium as a main component of the ink of the present invention, stable dispersibility and continuous discharge in ink jet printing can be maintained. When used for printing of a pharmaceutical edible substance such as a tablet, distilled water, water for injection, etc. are suitable. Here, the term “mainly composed of 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 composition is substantially water as a liquid component other than the specific water-soluble organic solvent described below.

[Water-soluble organic solvent]
In the present invention, it is desirable to contain a specific water-soluble organic solvent as a liquid component other than water. The addition of these water-soluble organic solvents makes it possible to prevent clogging of the head portion and adjust the drying property of the ink when used for printing by the inkjet method.
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 combination of two or more. Particularly preferably, as a food additive, ethanol, isopropanol, polyethylene glycol, propylene glycol, glycerin and the like are suitable.

  The amount of the water-soluble organic solvent added is preferably 5 to 30% by weight, and more preferably 6 to 25% by weight in the ink solution. In some cases, the dischargeability from the material may be reduced, or the drying speed may be reduced. If the addition is less than 5% by weight, problems may occur in the discharge of the nozzle, and the occurrence of blurring and the continuous discharge may not be possible.

[Surface tension modifier]
In the present invention, a surface tension regulator can be used as needed. The surface tension adjusting agent is a component having the functions of improving discharge from the nozzle and adjusting the surface tension.
Specific examples of surface tension modifiers are preferably surfactants such as nonionic surfactants, etc. Specifically, for example, alkyl benzene sulfonate, higher alcohol sulfate, higher fatty acid salt, higher alkyl dicarboxylate, alkyl Anionic surfactants such as naphthalene sulfonate, alkyl sulfosuccinate, naphthalene sulfonic acid formalin condensate salt, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phosphate, etc .; eg 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, polyoxyethylene addition acetylene glycol and the like are preferable, among which sucrose is preferable. Sucrose fatty acid esters such as monostearic acid esters 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 regulator 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.

[Sugars and other additives]
Sugars can be added for the purpose of improving the dischargeability and adhesion. Examples of sugars include monosaccharides, disaccharides and polysaccharides, and specific examples include glucose, galactose, mannose, gulose, talose, allose, altrose, idose, fructose, sorbose, tagatose, psicose, sucrose, maltose, Lactose, Maltotriose, Isomaltose, Maltotetraose, Isomaltotetraose, Isomaltotetraose, Panose, Nigerose, Kogybiose, Laccherose, Palatinose, Kestose, Nistose, Fructocilnystose, Inulobiose, Inurotriose, Inurotetra Examples include aus, isomaltellose, maltosyl sucrose, maltotriosyl sucrose, maltopentaose, maltohexaose, maltoheptaose and the like. Further, as the derivatives of these sugars, sugars obtained by reducing or oxidizing the above-mentioned sugars are preferable, and specific examples thereof include maltitol, sorbite and the like.
The addition amount thereof is preferably 1 to 20% by weight in the ink liquid, and has the function of improving the blur when printing on a recording medium and stabilizing the discharge.

  Further, in the ink of the present invention, orthophenylphenol, sodium orthophenylphenol, diphenyl, thiabendazole and imazalil are preferable as a fungicide to have desired physical properties, and hypochlorite as a germicide Sodium acid, hydrogen peroxide and ethanol are preferred. In addition, additives such as an antifoaming agent, a rust inhibitor, and a pH adjuster can be appropriately blended.

Further, the ink of the present invention is characterized by containing activated carbon as a coloring material, but other coloring materials may be contained without impairing the performance of the present invention.
However, for the printing use of the edible material described later, sufficient color development can be obtained even with activated carbon alone.

  In addition, for the purpose of adjusting the viscosity of the ink and the like, another water-soluble polymer may be added as appropriate, as long as the performance of the present invention is not impaired. Examples thereof include starches such as guar gum, locust bean gum, agarten and methyl starch, gelatin, pullulan, xanthan gum, tragacanth gum, dextrin and the like. In addition, other conventionally known dispersants may be added as long as the performance of the present invention is not impaired.

[Preparation of ink]
A sixth aspect of the ink of the present invention is an ink containing at least (i) a coloring material and (ii) a dispersion medium, wherein the coloring material is activated carbon, and the average dispersed particle diameter of the activated carbon in the ink is 50. It is an ink characterized by being -500 nm.
That is, the activated carbon in the ink according to the twenty-sixth aspect of the ink of the present invention has an average dispersed particle diameter of 50 nm to 1 μm, preferably 50 to 800 nm, more preferably 50 to 700 nm, still more preferably 50 to 600 nm, still more preferably It is 50 to 500 nm, more preferably 100 to 450 nm, and most preferably 150 to 400 nm. Within this range, the coloring power, the dispersion stability, the nozzle dischargeability, and the fixability to the printing material are the most excellent, especially in the range of 50 to 500 nm of the average dispersed particle diameter, regardless of the ink jet device or the nozzle. Each physical property is extremely excellent.

When the average dispersed particle size is less than 50 nm, aggregation tends to easily occur due to van der Waals' forces between particles, and the temporal stability tends to decrease. When the average dispersed particle size exceeds 1 μm, the coloring material may be easily separated in the liquid and the precipitation may easily occur.
In addition to controlling the average particle size, it is preferable to suppress the amount of coarse particles. If 90% or more of all the activated carbon particles in the liquid is adjusted to a dispersed particle diameter of 1 μm or less, more preferably 500 nm or less, an ink having even more excellent physical properties can be obtained. It is also conceivable to carry out dispersion treatment until the size of all the particles is in this range, but in order to prevent the generation of a large amount of too fine particles and reaggregation, dispersion treatment is carried out until the average particle diameter is in the above range. After carrying out, a method of removing coarse particles by a known method such as centrifugation 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: The stock solution is diluted with deionized water so that it falls within the defined measurement concentration range.
Measuring equipment: Dynamic light scattering type particle size distribution measuring instrument ("NIKKISO: Microlracwave-EX150")
Measurement time: 120 seconds

  Also in the first to fifth embodiments of the ink of the present invention described above, by setting the average dispersed particle diameter and the dispersed particle diameter of all the particles described above, the ink can have further excellent physical properties. Further, the dispersion medium, the water-soluble organic solvent, the surface tension regulator, the saccharides and other additives described above are common to the twenty-sixth embodiment of the ink of the present invention and can be suitably used. Also, in particular, the presence of the water-soluble polymer used in any one or more of the first to fifth embodiments of the ink of the present invention described above enables fineness of activated carbon to be characterized in the sixth embodiment of the ink of the present invention The dispersed state can be obtained easily and stably.

The viscosity of the ink according to the first to sixth aspects 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.
If the viscosity is less than 1.0 mPa · s, satellite phenomena may occur or droplets may not form droplets from the nozzle. Conversely, when the viscosity exceeds 10.0 mPa · s, the satellite phenomenon may also occur or the ink droplets may not be formed. The satellite phenomenon refers to a small droplet such as dust that separates from the main droplet of the ejected ink droplet from the head nozzle.

The measuring method of viscosity is as follows.
Conditioning: Stock solution
Measuring equipment: Conical flat type rotational viscometer (manufactured by Toki Sangyo Co., Ltd. "TVE-20L type" (part number))
Measurement condition: 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.
Furthermore, when the surface tension is less than 28 mN / m, a phenomenon occurs in which droplets are not ejected from the nozzle without sufficient droplets, and the same applies when the surface tension exceeds 40 mN / m.

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

[Preparation of ink]
In the preparation of the ink of the present invention, the above-described components may be mixed to form an ink. The mixing method is not particularly limited. For example, after mixing and stirring activated carbon, water-soluble polymer and water, the active carbon is dispersed in water by dispersing with a disperser, for example, a paint shaker, roll mill, ball mill, sand mill, jet mill, etc. It can be stabilized.

The method of removing coarse particles at this stage, and thereafter adding the water-soluble organic solvent and the surface tension regulator described above to form an ink is also suitable for securing a stable and favorable dispersed state.
Alternatively, the prepared ink can be subjected to filter processing or the like by a known technique, or impurity ions can be removed to further improve the quality.

[Printing method and application]
It is possible to print on various objects using the ink of the present invention described above. The ink of the present invention can be prepared using only components that can be safely taken into the body, and thus can be suitably used, for example, for printing on medicines such as tablets and capsules, or for printing on various food products. The printing method is also not limited, and may be used for offset printing, gravure printing, etc. conventionally used for printing edibles, but even when used for inkjet printing, stable dischargeability is maintained and excellent Performance can be demonstrated. That is, it can be used as an inkjet ink for printing using an inkjet printing device, and can be used as a marking ink for the surface of an edible body, and the ink of the present invention can be printed using the inkjet printing device An edible material can be produced by printing on a surface.
Since the printed matter obtained in this manner is excellent in colorability and fixability, the ink of the present invention is used for various purposes such as prevention of forgery, securing of traceability, prevention of accidental ingestion, improvement of distinguishability, impartation of amusement. It is possible to print on medicines, foods, etc.

The present invention will be described in detail by way of examples. In the examples, all "parts" indicate parts by weight, and all "%" indicate parts by weight.
The type and number average molecular weight of the water-soluble polymer used in Examples and Comparative Examples, and the measurement results of the weight average molecular weight and z average molecular weight are shown in Table 1. The measurement was performed twice and the average value was adopted.

Example 1
The components shown below were blended and stirred at room temperature for 1 hour with a propeller stirrer.

Component amount
(Parts by weight (hereinafter referred to as parts))
Activated carbon 10.0
(Average particle size: 25 μm, average pore diameter: 2.8 nm)
Polyvinylpyrrolidone 8.5
(Viscosity average molecular weight: 40,000, K value 30, number average molecular weight 6, 401, weight average molecular weight 27, 739, z average molecular weight 71, 598)
Water 81.5

Next, to the obtained mixture, 150 g of 0.7 mm diameter glass beads were placed in a pot for a paint shaker and shaken for 3 hours.
The 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 concentration is 10% by weight, to obtain “dispersion 1”, The ink was made 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 ink was prepared by stirring for 30 minutes with the above composition.
The obtained ink had an average dispersed particle size of 350 nm, a viscosity of 3.1 mPa · s, and a surface tension of 33 mN / m. Moreover, the obtained ink showed uniform black in appearance.
Further, with respect to the above-mentioned ink, the temporal stability, the ejection property, the fixing property, the light resistance and the water resistance were examined according to the following method. The results are shown in Table 1.

(A) Stability Test with Time The ink was put in a glass bottle and left in a thermostatic chamber at 5 ° C. for one month, and then the presence or absence of separation of the color material, floating of water and sedimentation was confirmed. The state in which the separation of the coloring material, the water float and the sedimentation occurred to any extent was evaluated as abnormal.
In Table 1, the case of no abnormality is indicated by ○, and the case of abnormality is indicated by x.

(B) Ejectability test Using an ink jet printer (manufactured by Qualicaps Co., Ltd.) and a droplet observation device, it is possible to discharge ink from the head, to form droplets, and to re-eject after the discharge is temporarily stopped. Was investigated.

(C) Fixability drying test A tablet immediately after printing with an ink jet printer was used as a sample, the printed part of the sample was rubbed with a non-woven fabric, and the presence or absence of extension of the ink and transfer of the ink to the non-woven 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 of light resistance test. The sample is placed in a light stability tester (LST-300D manufactured by Tokyo Rika Kikai Co., Ltd.), exposed to light at a total illuminance of 1.2 million lux · hr, and then the sample before exposed to light using a visual and spectrocolorimeter (SE6000 manufactured by Nippon Denshoku Kogyo Co., Ltd.) The difference between the color tone and the 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 with an ink jet printer, and a sample of the water resistance test was prepared. The sample was stored for 1 week in an atmosphere kept at a constant humidity (about 75% relative humidity) by adding a saturated solution of sodium chloride to a desiccator, and the presence or absence of bleeding in the printed portion was examined.
(F) Coloring test The printed portion of the sample after the test prepared in the test of (e) was checked visually to determine whether the printing could be determined and the color tone. In the case of black to dark gray (red when red color material was used), those which can be discriminated in printing well were marked 〇, and the others were marked x.

Comparative Example 1
An ink was produced in the same manner as in Example 1 except that activated carbon was replaced by red iron oxide and polyvinylpyrrolidone was replaced by gum arabic.
Comparative Example 2
An 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 components shown below were compounded and stirred at room temperature for 1 hour with a propeller stirrer.

Amount of activated carbon 10.0
(Average particle size: 30 μm, average pore diameter: 2.1 nm)
Polyvinylpyrrolidone 10.0
(Viscosity average molecular weight: 25,000, K value 25, number average molecular weight 4,495, weight average molecular weight 18, 291, z average molecular weight 51, 018)
Water 80.0

Next, 150 g of 0.7 mm diameter glass beads were placed in the paint shaker pot and shaken for 3 hours.
The 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 concentration is 10% by weight ("dispersion 2") The 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 ink was prepared by stirring for 30 minutes with the above composition.
The obtained ink had an average dispersed particle size of 250 nm, a viscosity of 2.5 mPa · s, and a surface tension of 32 mN / m. Moreover, the obtained ink showed uniform black in appearance.

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

Amount of activated carbon 10.0
(Average particle size: 35 μm, average pore diameter: 3.4 nm)
Polyvinylpyrrolidone 7.0
(Viscosity average molecular weight: 40,000, K value 30, number average molecular weight 6, 401, weight average molecular weight 27, 739, z average molecular weight 71, 598)
Water 83.0

Then, to the obtained mixture, 370 g of 0.5 mm diameter zirconia beads were placed in a pot for a paint shaker and shaken for 7 hours.
The coarse particles contained in the dispersion are removed to adjust the dispersion particle diameter to 90 nm or less and the solid content concentration to 10% by weight to 90% or more of the total particles, and the dispersion 3 is prepared. I inked.

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

The ink was prepared by stirring for 30 minutes with the above composition.
The obtained ink had an average dispersed particle size of 316 nm, a viscosity of 4.8 mPa · s, and a surface tension of 33 mN / m. Moreover, the obtained ink showed uniform black in appearance.

Comparative Example 3
An ink was prepared in the same manner as in Example 3 except that the activated carbon was replaced with a water-soluble black dye.

Example 4
The components shown below were compounded and stirred at room temperature for 1 hour with a propeller stirrer.

Amount of activated carbon 10.0
(Average particle size: 35 μm, average pore diameter: 3.4 nm)
Polyvinylpyrrolidone 7.0
(Viscosity average molecular weight: 25,000, K value 25, number average molecular weight 4,495, weight average molecular weight 18, 291, z average molecular weight 51, 018)
Water 83.0

Then, to the obtained mixture, 370 g of 0.5 mm diameter zirconia beads were placed in a pot for a paint shaker and shaken for 7 hours.
The coarse particles contained in the dispersion are removed to adjust the dispersion particle diameter to 90 nm or less and the solid content concentration to 10% by weight to 90% or more of the total particles, and the dispersion 3 is prepared. I inked.

Component amount (parts)
Dispersion 4 (solid content 10%) 48.0
Propylene glycol 10.0
Sucrose fatty acid ester 8.7
Water 33.3

The ink was prepared by stirring for 30 minutes with the above composition.
The obtained ink had an average dispersed particle size of 283 nm, a viscosity of 4.0 mPa · s, and a surface tension of 32 mN / m. Moreover, the obtained ink showed uniform black in appearance.

Comparative Example 4
In Example 4, an attempt was made to prepare an ink in the same manner as in Example 4 except that activated charcoal was replaced with Bincho charcoal, but when it was put into a propeller stirrer and stirred, it thickened rapidly to gelate and lost fluidity and uniformly dispersed. Since neither the liquid nor the ink could be obtained, neither test could be performed.

Comparative Example 5
In Example 4, polyvinyl pyrrolidone (viscosity average molecular weight: 25,000, K value 25, number average molecular weight 4,495, weight average molecular weight 18, 291, z average molecular weight 51, 018) was polyvinyl pyrrolidone (viscosity average molecular weight; An attempt was made to make an ink in the same manner except that the value was changed to 2.8 million, K value 120, number average molecular weight 142, 948, weight average molecular weight 525, 307, z average molecular weight 1, 106, 232). When it was added and stirred, it thickened and gelated, lost its fluidity, could not obtain a uniform dispersion, and could not be formed into an ink, so neither test could be performed.

  In Comparative Example 1 and Comparative Example 2, the ejection property was poor, and printing by the inkjet printer was difficult, and a sample for the water resistance test could not be prepared. Further, in Comparative Example 3, the characters printed on the tablets were blurred by the execution of the water resistance test, and it was difficult to distinguish the characters in the coloring test, and the density of the print was also low.

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

According to the present invention, it has excellent fixability to the tablet surface only with components that can be ingested in the body, and fixability and light resistance while enabling continuous discharge even in the ink jet method, especially in continuous type printing. It is possible to provide an excellent ink, a printing method using the same, and a method of producing an edible material.

Claims (11)

At least (i) a coloring material, an ink (ii) a dispersion medium, and (iii) viscosity average molecular weight contains polyvinylpyrrolidone 1,000～220,000, colorant Ri activated carbon der, dispersion medium An ink comprising one or more of ethanol, isopropanol, polyethylene glycol, propylene glycol and glycerin . At least (i) a coloring material, an ink containing (ii) a dispersion medium, and (iii) polyvinylpyrrolidone K value 10-90, colorant Ri activated carbon der, dispersion medium, ethanol, isopropanol, An ink comprising one or more of polyethylene glycol, propylene glycol and glycerin . At least (i) a coloring material, (ii) a dispersion medium, and (iii) an ink having a number average molecular weight (Mn) containing polyvinylpyrrolidone 2,000～140,000, colorant Ri activated carbon der, An ink , wherein the dispersion medium contains one or more of ethanol, isopropanol, polyethylene glycol, propylene glycol and glycerin . At least (i) a coloring material, (ii) a dispersion medium, and (iii) ink weight average molecular weight (Mw) contains polyvinyl pyrrolidone 4,000～500,000, colorant Ri activated carbon der, An ink , wherein the dispersion medium contains one or more of ethanol, isopropanol, polyethylene glycol, propylene glycol and glycerin . An ink containing at least (i) a colorant, (ii) a dispersion medium, and (iii) polyvinylpyrrolidone having a z-average molecular weight (Mz) of 10,000 to 1,000,000, wherein the colorant is activated carbon An ink , wherein the dispersion medium contains one or more of ethanol, isopropanol, polyethylene glycol, propylene glycol and glycerin . At least (i) a coloring material, an ink containing a polyvinylpyrrolidone and (ii) a dispersion medium, a colorant activated carbon, and Ri average dispersed particle diameter 50nm~1μm der activated carbon in the ink, the dispersion medium An ink comprising at least one of ethanol, isopropanol, polyethylene glycol, propylene glycol and glycerin . The ink according to any one of claims 1 to 6 , 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 any one of claims 1 to 7 , which is an inkjet ink. The ink according to any one of claims 1 to 8 , which is used for marking ink on the surface of edible material. A method for producing a edible body, comprising printing the ink according to any one of claims 1 to 9 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 9 on an orally ingested product by an ink jet printing apparatus.