JP2006335922A - Ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink suitable for forming an opaque part on a transparent material when printed on various foods, materials contacting with foods, food packaging materials, etc., especially an ink and a packaging material for the use to a light-shielding food packaging material and free from hygienic problem even in the case of contacting the ink, etc., directly with a food and directly contacting the mouth to the food or drink or to the printed part. <P>SOLUTION: The ink for food or food packaging use contains 1-50 wt.% one or more kinds of carbon powder pigment having an average particle diameter of 0.01-5μm and 1-50 wt.% one or more kinds of resins usable as a food additive. The invention further provides the above ink wherein the average particle diameter of the carbon powder pigment is 0.05-3μm, and the above ink containing a food color other than the carbon powder pigment in an amount of 0.3-20 wt.% based on the whole ink. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is suitable for printing on foods, unprocessed foods or processed foods, directly on these surfaces, or on packaging materials or materials that have an opportunity to come into contact with foods, food packaging materials, etc. It relates to ink.

Foods and food packaging materials are required to display the production location, producer display, production history, etc., and the expiration date. Clarification of production history, harvest date, expiration date, etc. is expected as a method for improving quality, confirming safety, reliability of products, and providing a sense of security.
Such a display is constructed in view of various code systems, search methods, and the like, but preferably, it is desired that each product is printed individually in the future.
Therefore, it is important for raw foods, processed foods and other objects directly, through packaging materials, etc., for materials that come into contact with food, or for materials that pass through food handling environments. It is a difficult task.

It is also important to process foods and related packaging materials such as letters, figures, designs, etc., to make products that incentivize purchase.
In such printing, the ink is required to be made of an edible material.
Furthermore, in materials for packaging foods, quality deterioration such as fading of contents due to visible light and ultraviolet light from the outside of the container during the storage period becomes a problem. In order to eliminate such a problem, the container is made of a material that does not transmit light, thereby preventing quality deterioration.

As such a material, there is a material by aluminum vapor deposition or the like, but handling becomes troublesome in recent disposal of containers and separation of materials in recycling.
Moreover, the method of providing a coating layer with the coating materials using pigments, such as carbon black, is also considered. However, in the process of forming the container, or as a container, it is difficult to avoid a part where the part coated with the paint is in contact with the food part as an end face. Moreover, the processing method for avoiding such a thing is not easy.
Therefore, even if the end face is in contact with food, an end face made of a material that is not harmful is preferable.

From such a viewpoint, an ink using a material composed of a food additive is desired.
In the case where it is not intended to block light, inks based on the following edible materials are known.
That is, a water-soluble dye that is a food additive colorant dissolved in water is known in the field of ink-jet inks, but because it is a pigment that dissolves in water, the color developability on a dark base material is not sufficient, Moreover, water resistance was inferior and it could not be used for the object which contacts water.

In the field of ink-jet ink, as an ink-jet ink excellent in water resistance and suitable for printing on the surface of food, Patent Document 1 (Japanese Patent Laid-Open No. 53-127010) discloses that the binder is shellac, water and A green ink composition is disclosed comprising a solvent comprising ethanol and sodium iron chlorophyllin or (and) copper chlorophyllin as colorants. However, the colorant such as copper chlorophyllin that is used does not have sufficient solubility in alcohol but is a water-soluble pigment, and the use of water is indispensable for increasing the ink concentration. Therefore, this ink is essentially composed mainly of water and is used by mixing a small amount of ethanol. The shellac resin is also of a type that is soluble in water, and in order to stabilize the dissolution, a non-food additive such as morpholine is used as the ink raw material. In addition, in order to maintain the solubility of the resin, a solvent such as methyl cellosolve was also used. These also consisted of materials that were not permitted in food additives.
Further, since it is a soluble dye, it was not suitable for a dark base material.

  Patent Document 2 (Japanese Patent Laid-Open No. 9-302294) discloses an ink containing a bayberry extract, a flavonoid substance, and an organic acid as an edible stabilizer. In this patent document 2, an edible stabilizer is shown, which aims to stabilize the light resistance of the dye. The ink is an ink that uses 70 parts by weight or more of water, and the dye and stabilizer have solubility only in water, and only about 20 parts by weight is used in consideration of solubility in ethanol. is not. Therefore, when the printed matter comes into contact with water, it is recognized as a category of so-called water-based ink in which pigments, resins, and the like are easily dissolved by water.

  Although these inks have been shown to have good light stability, they are inks that contain more water than ethanol, so that the drying property is such that more than 70 parts by weight of the solvent component is used as alcohol. No good alcohol type ink formulation is disclosed. Further, the resin used is a water-soluble type resin and is not a water-resistant ink mainly composed of alcohol.

In addition, when printing on foods, if the substrate to be printed is transparent, or conversely black or highly brown, etc. However, it has a tendency to cause problems such as a case where the required concealing property cannot be obtained due to excessive transparency, and the effect of printing cannot be confirmed by the color of the base.
As a light-shielding material that is not a food material, use of carbon black or inorganic particles having a large particle size is conceivable. However, when it comes to food materials, there are limitations that make it impossible to consider the original safety.

As an alternative to carbon black, there is a material composed of bamboo and plant sumi, and Patent Document 3 (Japanese Patent Laid-Open No. 2002-212474) uses acaloid as a binder and charcoal powder as an edible colorant. Printed on edible inks and plastics.
However, it cannot be fully confirmed whether acaloid is a food additive. Therefore, it is not necessarily an edible ink composed of food additives. Moreover, although it is estimated easily that a black printed matter is formed, a technique for forming a packaging material having a light shielding property is not mentioned.

Moreover, although patent document 4 (Unexamined-Japanese-Patent No. 10-251562) describes the electromagnetic wave shielding coating material using the bamboo charcoal which passes a 300 mesh sieve, it does not describe the light-shielding property for foodstuffs.
In addition, Patent Document 5 (Japanese Patent Laid-Open No. 2003-268290) does not disclose a technology for use as a food or food ink although a paint using plant-derived charcoal powder is used.

In addition, Patent Document 6 (Japanese Patent Laid-Open No. 2000-14495) discloses a far infrared ray and Patent Document 7 (Japanese Patent Laid-Open No. 2002-94284) discloses an electromagnetic wave shield as Patent Document 8 (Japanese Patent Laid-Open No. 2003-2003). 89770) as a building material, Patent Document 9 (Japanese Patent Laid-Open No. 2003-119428), as a deodorant component for aerosol, and Patent Document 10 (Japanese Patent Laid-Open No. 2004-331682). Patent Document 11 (Japanese Patent Application Laid-Open No. 2005-105010) and the like describe use as formaldehyde adsorption and VOC adsorption functional materials, but do not describe food-use inks.
As described above, in applications that impart opacity to printing inks, and for the purpose of constituting a food or food additive, there are restrictions on materials, and the use of materials for printing inks is limited. This adjustment was difficult and this adjustment was difficult.

Japanese Patent Laid-Open No. 53-127010 JP 09-302294 A JP 2002-212474 A Japanese Patent Laid-Open No. 10-251562 JP 2003-268290 A JP 2000-14495 A JP 2002-94284 A JP 2003-89770 A JP 2003-119428 A JP 2004-331682 A JP 2005-105010 A

An object of this invention is to provide the ink suitable for formation of the opaque part in a transparent material, when printing on various foodstuffs, the material which touches foodstuffs, food packaging materials, etc.
Particularly suitable for food packaging materials with light-shielding properties, which may come into direct contact with food, and when food or drink comes into contact with food, or where the printed part directly touches the mouth The purpose of the present invention is also to provide an ink and a packaging material that can eliminate concerns about hygiene.

In addition, when printed on various foods, food-contact materials, food packaging materials, etc., ink that does not cause coloration elution and does not cause disgusting appearance even when wet, and printed foods or packaging The purpose is to provide materials.
Another object of the present invention is to provide an ink composed only of a material that can be added to food and a packaging material printed with the ink.

  That is, the present invention includes 1 to 50% by weight of one or more carbon powder pigments having an average particle diameter of 0.01 to 5 μm, and 1 to 50% by weight of one or more resins that can be added to food. The present invention relates to a food or a food packaging ink.

  Moreover, this invention relates to the said ink whose average particle diameter of a carbon powder pigment | dye is 0.05-3 micrometers.

  Moreover, this invention relates to the said ink which contains 0.3-20 weight% of edible pigments other than a charcoal pigment | dye further.

  Moreover, this invention relates to the said ink whose edible pigment | dye is an extraction pigment | dye from a natural product.

  The present invention further relates to the above ink containing an emulsifier capable of food addition.

  The present invention also relates to the above ink, wherein the food-addable resin is shellac resin.

  The present invention also relates to the above ink, wherein the carbon powder pigment is obtained by carbonizing a plant by heating it to a high temperature by a steam activation method.

  Further, the present invention provides the above ink, wherein the charcoal pigment is obtained by roasting the shell of cacao fruit, by burning vegetable oil or fat, or bamboo charcoal.

  Moreover, this invention relates to the said ink whose ink is for gravure.

  The present invention also relates to the above ink, wherein the ink is for flexo.

  The present invention also relates to the above ink, wherein the ink is for pad printing.

  Moreover, this invention relates to the said ink whose ink is an object for screen printing.

  The present invention also relates to a printing method for performing opaque printing on foods and / or food packaging materials using the above ink.

  The present invention also relates to the above printing method, wherein the ink layer thickness is set so that the transmittance of light having wavelengths of 320 nm, 356 nm, 500 nm, 600 nm, and 900 nm of the ink layer after printing is 30% or less.

  The present invention also relates to a food or packaging material obtained by printing the above ink with opaque printing on a food and / or food packaging material.

  The present invention also relates to the above packaging material, wherein the ink layer after printing has a light transmittance of wavelengths of 320 nm, 356 nm, 500 nm, 600 nm, and 900 nm of 30% or less.

According to the present invention, it is possible to provide an ink constituted only by a material that is allowed to be added to foods and a packaging material printed with this ink. Therefore, a packaging material having a high concealment effect can be used with peace of mind.

(Smoke powder pigment)
The ink of the present invention uses charcoal pigment as an edible pigment and an opaque material.
The carbon powder pigment used in the present invention is obtained by carbonizing a plant. For example, the carbon powder pigment is obtained by heating a plant to a high temperature by a steam activation method and carbonizing the plant. Specific examples include those recognized as food additive pigments, such as roasted cacao fruit shells, burned vegetable oils and fats, bamboo charcoal which is a bamboo carbide, and the like. In the present invention, a carbon powder pigment is derived from a plant.

  Since carbon powder pigments can be used as a concealing material, those having an average particle diameter of 0.01 to 5 μm are used in the present invention. However, a particle diameter of 0.05 to 3 μm is preferable in the ink making process. Furthermore, it is preferable to disperse | distribute as 1 micrometer or less in the dispersion | distribution process in ink.

The average particle diameter can be determined by a light scattering method or the like.
In general, plant carbides are in the form of lumps, so they are refined by a pulverizer.
As such a miniaturization method, various pulverizing and dispersing machines by mechanical impact are used.

As a method of further reducing the particle size, a method of dispersing the carbon powder pigment and the edible resin in a plate shape with two rolls, a high viscosity mixture of the carbon powder pigment and the edible resin with three rolls A method of dispersing, a method of dispersing with a high-speed agitator mill in a medium viscosity state, a method of applying an impact with a carbon powder pigment and an edible resin with a ball mill while reducing the solvent content, and the like are appropriately used.
The carbon powder pigment is used in the whole ink in an amount of 1 to 50% by weight, preferably 8 to 50% by weight, and more preferably 15 to 25% by weight.

In the present invention, the carbon powder pigment is poorly soluble in water or alcohol. Therefore, it can be used in the form of dispersion with a particle size of 0.01 to 5 μm.
Good opacity and black color reproduction are possible with this particle size and the above-mentioned use amount. Moreover, it can be an ink form superior in sedimentation compared to inorganic white powder.

(Food color)
In the present invention, edible pigments other than the carbon powder pigment can be used together with the carbon powder pigment. As the food color that can be used in the present invention, natural color or synthetic color that is insoluble or poorly soluble in alcohol or water is used.
In some cases, natural pigments or synthetic pigments that are soluble in alcohol or water, or natural pigments or synthetic pigments that are partially dissolved in water or alcohol containing propylene glycol are used.
For applications that do not require water resistance, water-soluble dyes are used.

Specific examples of the dye include a turmeric dye, a gardenia dye, a beige powder dye, a cucumber dye, a rose dye, an anato dye, an akane dye, an anthocyanin dye, a chlorophyllin dye, a food red, a food yellow, and a food blue.
In the natural pigment system, alcohol-soluble quorian pigment, rosewood pigment, turmeric pigment and the like are preferable. These pigments are pigments extracted with a mixed solvent of alcohol and water.

  Edible pigments such as charcoal powder or bamboo charcoal are preferably contained in the ink in an amount of 1 to 50% by weight. When the content is less than 1% by weight, the print density is insufficient, and when the content exceeds 50% by weight, poor dispersion and poor printability occur. In particular, the stability tends to deteriorate in continuous printing.

(Resin capable of food addition)
In the ink of the present invention, by using one or more kinds of resins that can be added to food, it has water resistance and friction resistance with which the printed ink does not elute even if it is immersed in water or rubbed. be able to.

As a resin to which food can be added, an edible resin is used, and shellac resin, dammar resin, and copal resin are easy to use because of their solubility in alcohol solvents. In addition, water-based resins may be used, and carboxymethyl cellulose, methyl cellulose, crystalline cellulose, gelatin, casein, soybean protein, gum arabic cyclodextrin and the like can be used in whole or in part depending on the solvent.
Among these resins, a shellac resin is a preferable resin from various aptitudes.

As the shellac resin used in the present invention, an alcohol-soluble resin is particularly preferably used. This shellac resin is compatible with the food dye used in the present invention. In addition, it functions to dissolve in alcohol and increase the viscosity of the ink, and also functions as a good binder for the substrate.
In addition, there is a shellac resin of a type that dissolves in a water / alcohol mixed solvent, and this type of shellac resin is preferable in order to emphasize stability on the alkali side.

  In the present invention, the resin to which food can be added is contained in the whole ink in an amount of 1 to 50% by weight, preferably 4 to 40% by weight. When the content is less than 1% by weight, preferably less than 4% by weight, an appropriate viscosity cannot be obtained. Moreover, it is difficult to obtain sufficient adhesion. On the other hand, if it is 50% by weight or more, preferably 40% by weight or more, the viscosity of the ink becomes too high, the fluidity at low temperature is insufficient, and the printing stability is also lowered.

(Ink solvent)
In the present invention, the ink can contain one or more solvents. The solvent can be used in an amount of 30 to 85% by weight in the entire ink.
As a solvent in the ink of the present invention, ethanol is superior in terms of drying property.

  The ink of the present invention is preferably essentially composed of ethanol as a solvent, and in the ink, an alcohol ink containing at least 50% by weight of ethanol is a prescription suitable for a water-resistant ink. . Ethanol that can be used in the present invention is food-grade fermented ethanol or denatured ethanol.

Propylene glycol can be used to perform the roles of improving the solubility of the pigment, adjusting the drying of the ink, adjusting the ink viscosity, and the like. In addition, depending on the foundation, it also has an effect of adjusting penetration.
Propylene glycol is used in the range of 0 to 30% by weight in the ink. Appropriate penetration into the printing material and adjustment of drying are possible.

(emulsifier)
In the present invention, the ink may contain one or more food-addable emulsifiers.
As the emulsifier, glycerin fatty acid ester, sucrose fatty acid ester, lecithin and the like are used. These are used in an amount of 0 to 5% by weight. Contributes to the dispersion stability of the charcoal pigment in the ink.
In these emulsifiers, the nonionic active agent is suitable for HLB depending on the type of ink, HLB 8-16 for gravure and pad inks, HLB 4-7 for aqueous type screen inks, For materials such as chocolate, ink adjustment such as HLB1-2 has suitability for printing.

(Packaging material)
The ink of the present invention can form printed matter with good water resistance, and depending on the printing system, high-speed variable information can be printed.
The ink of the present invention can be used for foods, materials that come into direct contact with foods, and food packaging materials. Examples of such a packaging material include plastic materials such as polypropylene, polyethylene, nylon, and polyethylene terephthalate that have been surface-treated as necessary, nonwoven fabric, and paper. By printing on the entire surface, a light-shielding package can be formed.

The food packaging material is a material for forming a container, and in particular, a material used in an application where it is necessary to prevent deterioration of food by light. Such a material requires light-shielding properties depending on the type of food.
Moreover, in the formation of a container, there exists a form which has a possibility that the end surface of a packaging material may contact with a foodstuff, and this material has the suitability as a packaging material to such a container.
That is, a printing surface in which the ink layer is reduced by 70% or more in transmittance is formed with an ink composed of charcoal pigment and a resin to which food can be added.

In addition, the ink of the present invention can be used to produce a laminated film for food packaging containers. Since the ink is composed of additives, hygiene concerns can be eliminated.

The ink of the present invention is an ink using 1 to 50% by weight of one or more carbon powder pigments having an average particle diameter of 0.01 to 5 μm, and preferably, the content is an ink of 15 to 25% by weight. By using the ink layer thickness as 1 to 5 μm, the transmittance of ultraviolet light, visible light, and near infrared light can be cut by 70% or more. Furthermore, a cut of 95% or more can be achieved by setting the ink layer thickness to 2 to 8 μm.
A method of preparing an ink layer having a film thickness of 1 μm or less and laminating two or more ink layers is also a preferable method for improving the light shielding property.
Even in this case, even when the container is formed, it may be in contact with food, or may be directly in contact with the mouth when eating or drinking after opening, the concern about hygiene can be eliminated.

Furthermore, the ink of the present invention is composed of those recognized as food additives, and is also effective for food design, decoration, high-quality data display, quality traceability, and the like.
In addition, it can be used for various types of printing such as gravure, flexo, pad printing, screen printing, etc. The printed design and data include the place of production, date of harvest, producer, date, special symbol. Etc. can also be printed.

  These notations give reliability to the distribution form of the product as a reliable display method of the route.

Examples of foods to be printed include gums, candies, biscuits, cookies, buns, and chocolates. There are also fruits, vegetables, and meats such as oranges, apples, and watermelons.
These food packaging materials are also subject to printing.

Hereinafter, the present invention will be described in detail with reference to examples. In the examples, parts and% indicate parts by weight and% by weight, respectively.
Example 1-1
Average particle diameter 1.74μm D99 2.21μm carbon powder pigment (by plant steam activation method) 15%, shellac resin 28%, glycerin fatty acid ester 2%, fermentation ethanol 55% in a sand mill using zirconia beads Dispersion was carried out, and an ink of 20 seconds was produced with Zahn Cup No. 3.
A solid ink layer was provided on the polyester film by gravure printing so as to have a film thickness of 2 μm.

The spectral transmittances at 320 nm, 356 nm, 500 nm, 600 nm, and 900 nm by printing this film were 7.6%, 7.5%, 7.6%, 7.6%, and 8.4%, respectively, and the transmittance decreased by 90% or more.
When the ink layer thickness was 5 μm, the transmittance decreased by 99% or more at 0.5%, 0.5%, 0.5%, 0.56%, and 0.5%.

Example 1-2
When the charcoal pigment of Example 1-1 was 8%, the fermentation ethanol was 62%, the ink was adjusted, and the ink layer thickness was changed to 2 μm, the transmittance was measured in the same manner. 10%, 10%, 10%, 10%, and 11%, and the transmittance of the charcoal powder was reduced by 70% or more when the ink was 8% or more.

Example 1-3
When the carbon powder pigment concentration in Example 1-1 was 3%, the transmittance was 66%, 66%, 66%, 66%, 71% and 30% when the film thickness was 2 μm. The above reduction was possible.

Example 1-4
In addition, the carbon powder pigment concentration of Example 1-1 was 7%, and when the film thickness was 2 μm, the transmittance was 35%, 35%, 35%, 35%, 39%, A reduction of 30% or more was possible.

(Examples and Comparative Examples)
The raw materials shown in Table 1 below were mixed and dispersed by an emulsifier, and then filtered through a 20 μm filter to prepare an ink. The ethanol used in this example is 95% or more fermented ethanol.
About the ink obtained by the Example and the comparative example, the viscosity (mPa * s) in 25 degreeC was measured. The viscosity was measured using a viscometer ("Digital Viscomate" manufactured by YAMAICHI).

  Moreover, the ink obtained by the Example and the comparative example was printed on the to-be-printed body with the gravure test printing machine, and the following evaluation was performed about the obtained printed matter. The results are shown in Table 2. Moreover, the same ink was pad-printed on the white chocolate sugar coating surface with the pad printing machine which has a silicon rubber plate, and the check property of printed matter was evaluated.

Particle size: Measured with a particle size distribution meter (UPA manufactured by Nikkiso Co., Ltd.).
Sedimentability: Ink was placed in a glass tube with a diameter of 10 mm to a height of 45 mm, and the state of separation after half a day was measured.
Adhesion: Ink applied to various printed materials, and whether or not there is peeling by rubbing a cotton swab.
Water resistance: Check for elution by rubbing with a cotton swab moistened with water.
Change over time: The ink is stored in a screw tube (glass container), and the presence or absence of sediment on the bottom and aggregate on the wall surface is evaluated visually.
Transmittance: Transmittance at 600 nm by a spectrophotometer. The ink film thickness is 1.5μm, 2μm, 4μm.

Example 8
The screen ink for chocolate was prepared by dispersing in a hot bath at 60 ° C. with the composition shown in Table 3.

  In Example 8, in printing on white chocolate, troubles of ink transfer from the screen and clogging on the screen were also good. The fluidity during printing was also good.

Example 9 and Comparative Example Table 4 was dispersed in an emulsifier to prepare an aqueous screen ink.

The ink of Example 9 was printed by screen printing on cookies. Since the ink of Comparative Example 1 was highly transparent, the image could not be discriminated by the base, but the ink of Example 9 lost transparency and formed a good image.
Example 10 and Comparative Example 2
The composition shown in Table 5 was dispersed in an emulsifier to prepare gravure and flexographic inks.

The ink of Example 10 was printed by flexographic printing on a PET film. Since the ink of Comparative Example 2 was high in transparency, the image could not be discriminated by the groundwork, but the ink of Example 10 lost transparency and formed a good image. The ink of Comparative Example 2 has a large amount of resin, but calcium carbonate easily settles and separates from the ink, but the ink of Example 10 has less sedimentation than that of Comparative Example 2 and can continue to be printed stably. Comparative Example 2 Ink became a printed matter with transparency and the influence of the groundwork could not be ignored. The concealability of ultraviolet light, visible light, and near infrared light could not be controlled.
In Example ink, even when a dark color material was placed at the bottom of the printing surface, the characters and design of the printing could be confirmed sufficiently. The light shielding property was sufficient.

Example 11 and Comparative Example 3
The composition shown in Table 6 was dispersed in an emulsifier to prepare a gravure ink and printed on a food PET film. The ink of Comparative Example 3 was liable to settle and lacked stability. Further, the ink of Example 11 had a concealing property, whereas the ink of Comparative Example 3 was a printed matter that had transparency and the influence of the base could not be ignored. The concealability of ultraviolet light, visible light, and near infrared light could not be controlled.
In Example 11, even when a dark color material was placed at the bottom of the printing surface, the characters and design of printing could be sufficiently confirmed. The light shielding property was sufficient.

Example 12 and Comparative Example 4
The composition shown in Table 7 was dispersed in an emulsifier to prepare a gravure ink and printed on a food PET film. The ink of Comparative Example 4 was liable to settle and lacked stability. In contrast, the ink of Example 12 had a concealing property, whereas the ink of Comparative Example 4 was a printed matter that had transparency and the influence of the base could not be ignored. In Example 12, even when a dark color material was placed at the lower part of the printing surface, the characters and design of printing could be sufficiently confirmed. The concealability of ultraviolet light, visible light, and near infrared light could not be controlled.

Claims (16)

1 to 50% by weight of one or more charcoal pigments having an average particle size of 0.01 to 5 μm and 1 to 50% by weight of one or more resins to which food can be added Ink. The ink according to claim 1, wherein an average particle diameter of the carbon powder pigment is 0.05 to 3 µm. Furthermore, the ink of Claim 1 or 2 containing 0.3-20 weight% of edible pigments other than a charcoal pigment in the whole ink. The ink according to any one of claims 3 to 4, wherein the food coloring is an extraction coloring from a natural product. Furthermore, the ink in any one of Claims 1-4 containing the emulsifier which can add foodstuffs. The ink according to any one of claims 1 to 5, wherein the food-addable resin is a shellac resin. The ink according to any one of claims 1 to 6, wherein the carbon powder pigment is carbonized by heating a plant to a high temperature by a steam activation method. The ink according to claim 1, wherein the charcoal pigment contains roasted cocoa fruit shells, burned vegetable oil or fat, or bamboo charcoal. The ink according to any one of claims 1 to 8, wherein the ink is for gravure. The ink according to any one of claims 1 to 8, wherein the ink is for flexo. The ink according to any one of claims 1 to 8, wherein the ink is for pad printing. The ink according to any one of claims 1 to 8, wherein the ink is for screen printing. A printing method for performing opaque printing on a food and / or food packaging material using the ink according to claim 1. 14. The printing method according to claim 13, wherein the ink layer thickness is set so that the transmittance of light having wavelengths of 320 nm, 356 nm, 500 nm, 600 nm, and 900 nm of the printed ink layer is 30% or less. A food or packaging material obtained by printing the ink according to any one of claims 1 to 12 with opaqueness on food and / or food packaging material. 16. The packaging material according to claim 15, wherein the ink layer after printing has a transmittance of light of wavelengths of 320 nm, 356 nm, 500 nm, 600 nm, and 900 nm of 30% or less.