JP2010248313A - Inkjet ink, method for manufacturing the same, and method for using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet ink desired which forms a non-transparent clear setting record to thereby give a satisfactory visibility, and elutes none of coloring matter even when wetted with water, in the case of recording on a variety of foods, the materials contacting with foods, food-packaging materials, etc. <P>SOLUTION: This inkjet ink includes carbon black coloring matter, a shellac resin, a cellulose-based resin, ethanol and water, each of which is permitted as a food additive. This inkjet ink is manufactured by a manufacturing method which comprises the first process of obtaining a dispersion by dispersing carbon black coloring matter into a resin solution in which a cellulose-based resin is dissolved in a first solvent containing water of 50 wt.% or more relative to the whole solvent and the second process of dispersing additionally the dispersion obtained in the first process into a shellac solution in which a shellac resin is dissolved in a second solvent containing ethanol of 50 wt.% or more relative to the whole solvent. There is also provided the method for using such an inkjet ink on an inkjet printer as is diluted with a diluting solvent containing ethanol, water and ammonium carbonate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is used for printing and recording on the surface of foods (foods include medicinal tablets; the same applies hereinafter), packaging materials that wrap foods, materials that have an opportunity to come into contact with foods, and the like. The present invention relates to an ink, and more particularly, to an ink-jet ink having improved drying properties with ethanol, a method for producing the same, and a method for using the same.

  In recent years, food and food packaging materials are required to display the production location, producer, production history, and the like, and regarding quality, it is necessary to display the expiration date, date of manufacture, and the like. Displaying these pieces of information can confirm safety and provide a sense of security and reliability for the product. In addition, the quality can be improved from such a viewpoint.

  On the other hand, processing characters, figures, designs, and the like on foods and related packaging materials is also an important factor for making a product that incentivizes purchase. When recording directly on food, it is naturally necessary to use ink made of edible materials, but when recording on materials related to food, such as packaging, using edible ink materials, A sense of security can be obtained. From such a viewpoint, an ink composed of a material composed of a food material or a food additive is desired.

  However, preparing inks made of foods or food additives has limitations on the ink materials. In addition, since there are few types of such ink materials, it is difficult to prepare them in the same manner as general inkjet inks. Conventionally, ink made of food additives has been known as a food-related measure. For example, a water-soluble dye that is a food additive colorant dissolved in water is known as an inkjet ink. However, since such an ink contains a pigment that dissolves in water, it has poor water resistance and cannot be used for an object that contacts water. In addition, for a dark recording object, there is too much transparency and the density is not sufficient.

  Therefore, Patent Document 1 below discloses an inkjet ink that is excellent in water resistance and suitable for printing on the surface of food. This ink is a green ink composition containing shellac resin as a binder, ethanol and water as solvents, and iron chlorophyllin sodium or (and) copper chlorophyllin sodium as a colorant. By the way, the colorants such as copper chlorophyllin that are used are water-soluble pigments that do not have sufficient solubility in alcohol, so it is essential to use a large amount of water in order to increase the ink concentration. become. Therefore, this ink is essentially composed mainly of water and is used by mixing a small amount of ethanol. In addition, some of the materials that were not allowed for food additives were used.

  Patent Document 2 discloses an ink containing a bayberry extract or the like as an edible stabilizer. In this patent document 2, it aims at stabilizing the light resistance of a pigment | dye. The composition of the ink is an ink that uses 70% by weight or more of water as a whole, and the dye and stabilizer are exclusively soluble in water, and ethanol is used only about 20% by weight of the whole ink. Absent. Accordingly, it is recognized that water-based inks in which pigments, resins, and the like are easily dissolved by water are shown, and the constitution is different from that of alcohol-type inks containing a lot of alcohol with good drying properties.

Also, if the object to be printed and recorded is transparent, or conversely black or dark brown, etc., the ink will be transparent when printing with colored natural pigments that dissolve in the solvent. Therefore, problems such as a lack of opacity in the required printed portion and a failure to confirm the printing effect due to the underlying color are likely to occur.
When it is not necessary to use a food material, use of carbon black or inorganic particles having a large particle size is also conceivable. However, when these are used, when food or a material that comes in contact with food is used as a recording object, naturally, there is a limitation, and consideration for the original safety cannot be achieved.

As food materials or food additives that replace carbon black, materials composed of bamboo and plant sumi are known.
Patent Document 3 discloses an edible ink and a printed matter on plastic using an acaloid resin as a binder and charcoal powder as an edible color material. However, acaloid resin is a special natural resin, and it is difficult to judge whether it is approved as a food additive by the Food Sanitation Law.

Patent Document 4 describes an electromagnetic wave shielding paint using bamboo charcoal, but does not describe an ink jet ink having opacity for food.
Patent Document 5 discloses a paint using plant-derived charcoal powder, but uses an acrylic emulsion, and there is no technical disclosure until it is used as food or ink for food.

  In addition, Patent Document 6 discloses a paint for far infrared rays as a material using bamboo or charcoal. Patent Document 7 discloses a paint for electromagnetic wave shielding. Patent Document 8 discloses a paint as a building material. Patent Document 9 discloses a deodorant component for aerosol. Further, Patent Document 10, Patent Document 11 and the like describe uses as an adsorption functional material for formaldehyde adsorption and VOC. However, they do not describe inks for food.

Patent Document 12 discloses an ink composed of charcoal and a non-aqueous solvent such as liquid paraffin. Although various activators are shown, there is no description of ingredients that will fix charcoal.
Patent Document 13 discloses a method of treating charcoal with hypochlorous acid. Although there is no disclosure of a specific formulation for this ink, it is recognized that it is intended for water-based inks mainly composed of water. There is no description on the suitability of drying properties for films and the like.
Patent Document 14 discloses an ink composed of charcoal and a non-polar non-aqueous solvent. There is no description about the component which fixes charcoal in this.

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 JP 2007-106915 A JP 2007-126583 A JP 2007-126592 A

An object of the present invention is to provide an inkjet ink having sufficient visibility even when recorded on various foods, materials in contact with food, food packaging materials, and the like. It is another object of the present invention to form an opaque clear print record without a decrease in visibility due to being transparent like a dye even when the recording object is dark. In addition, when recorded on various foods, food-contacting materials, food packaging materials, etc., inks that have been recorded in foods and packaging materials that do not dissolve pigments and do not cause disgusting appearance even when wet. The purpose is to provide. In addition, for the purpose of providing ink composed only of materials that are allowed to be added to food, and packaging materials recorded with this ink, in particular, it may be in direct contact with food, and in contact with food when eating or drinking Alternatively, even when the recording part is in direct contact with the mouth, the object is to eliminate concerns about hygiene.
The subject of the present invention is a food that is safe even if it is put in the mouth, but since foods such as tablets that are restricted by health food or the Pharmaceutical Affairs Law can also be put in the mouth, It is handled as the same recording object.

  As a result of intensive studies to solve the above-mentioned conventional problems, the present inventors have been approved as a food additive on the premise that ethanol is included for improving drying properties. By using powdery dye, shellac resin, cellulosic resin, and water, it was possible to realize an inkjet ink in which carbon powder dye was stably dispersed in shellac resin and water ethanol solvent.

 That is, the ink-jet ink according to the present invention comprises charcoal powder pigment, shellac resin, cellulosic resin, ethanol, and water, all of which are approved as food additives. In this case, approval as a food additive follows the provisions of the Food Sanitation Law. The same applies hereinafter.

  Moreover, this invention provides the inkjet ink which further contains the electrically conductive agent approved as a food additive in said structure.

  In the present invention, 1 to 20 parts by weight of carbon powder pigment, 1 to 20 parts by weight of shellac resin, 0.1 to 10 parts by weight of cellulose resin, and 40 to 90 parts by weight of ethanol, all of which are approved as food additives. An ink-jet ink comprising 3 parts by weight, 3 to 20 parts by weight of water, and 0.1 to 2 parts by weight of a conductive agent is provided.

  Furthermore, the present invention includes 1-20 parts by weight of Bincho charcoal, 1-20 parts by weight of shellac resin, 0.1-10 parts by weight of hydroxypropyl cellulose, 40-90 parts by weight of ethanol, 3-20 parts by weight of water, and sodium lactate. An inkjet ink comprising 0.1 to 2 parts by weight is provided.

  Moreover, this invention provides the inkjet ink whose carbon powder pigment | dye in each said structure is a powder of Bincho charcoal.

  And this invention provides the inkjet ink which further contains the pH adjuster approved as a food additive in each said structure.

  Furthermore, the present invention provides a method for producing the ink-jet ink according to claim 1 or claim 3, wherein the resin solution is obtained by dissolving a cellulosic resin in a first solvent containing 50% by weight or more of water as a whole. In addition, a first step of obtaining a dispersion by dispersing carbon powder pigment and a shellac solution in which a shellac resin is dissolved in a second solvent containing 50% by weight or more of ethanol as a whole are obtained in the first step. And a second step of further dispersing the dispersion. A method for producing an ink-jet ink is provided.

  Further, in the present invention, when recording on a food-related recording object using an inkjet printer using the inkjet ink according to claim 3, the inkjet ink is diluted with a diluent solvent containing ethanol, water, and ammonium carbonate. The present invention provides a method for using inkjet ink, which is characterized by being used in an inkjet printer.

  According to the present invention, since the ink was prepared using carbon powder pigment, shellac resin, cellulose resin, ethanol, and water, an inkjet ink in which carbon powder pigment was stably dispersed in shellac resin and water ethanol solvent was obtained. I was able to. According to the present invention, a black inkjet ink composed only of a material that is allowed to be added to food is obtained. Inks composed of food materials and food additives in this way can be used with confidence in food packaging materials, and foods or packaging materials recorded with these inks can be mixed into food during the recording process. Even if there is contact, the packaging can be carried out without any problem. When the ink of the present invention is used for recording on various foods, materials in contact with food, food packaging materials, etc., sufficient visibility can be provided to the recorded portions. Further, even when the recording object is a dark color, an opaque and clear print record can be formed without causing a drop in visibility as in the case of using a transparent dye. In particular, even when food is in direct contact with food, or when food is in contact with food or when the recorded portion is in direct contact with the mouth, hygiene concerns can be eliminated. And when it records on various foodstuffs, the material which touches foodstuffs, food packaging materials, etc., even if it gets wet, there is an advantage that a black pigment does not elute and it does not give an aversion to the appearance.

In addition, according to the method for producing an ink-jet ink according to the present invention, first, a cellulose resin that is easily soluble in water is dissolved in a first solvent mainly composed of water to form a resin solution. Is easily dispersed to form a dispersion. On the other hand, a shellac resin that is easily soluble in ethanol is dissolved in a second solvent mainly composed of ethanol to form a shellac solution, and the dispersion is mixed with the shellac solution. Thereby, the ink in which the carbon powder pigment | dye in a dispersion was disperse | distributed stably can be obtained. Incidentally, even if it is attempted to directly add and disperse the carbon powder pigment in the second solvent mainly composed of ethanol, the carbon powder pigment is not stably dispersed in the second solvent.
According to the method of using the ink-jet ink according to the present invention, since it is used in an ink-jet printer while appropriately diluting the ink-jet ink with a diluting solvent comprising ethanol, water, and ammonium carbonate, Even when printing is performed, ink concentration in the printer can be prevented, and the pH can be maintained on the alkali side. Accordingly, the solubility of the shellac resin is not lowered in the ink, the stability of the ink is ensured, and the long-term continuous printing performance can be stably continued.

`` Charcoal powder ''
The ink-jet ink according to the present invention is an ink for an ink-jet printer that prints and records by jetting ink onto a recording object, and is composed of all the components approved as food additives. This ink uses charcoal pigment as an edible pigment and an opaque material.
The charcoal pigment used in the present invention is not particularly limited as long as it is approved as a food additive, but, for example, those containing carbon as a main component obtained by carbonizing a plant are preferable from the viewpoint of food-related applications. As such plant-derived carbon powder pigments, those obtained by roasting the shells of cacao fruits are generally known. For example, those obtained by heating and carbonizing a plant by a steam activation method and those obtained by burning vegetable oils and fats are recognized as food additive pigments. Bamboo charcoal, which is a charcoal of bamboo, charcoal such as hardwoods and conifers, and the like are also exemplified as plant charcoal powder.

  In the present invention, among the charcoal pigments derived from plants, those using raw materials such as hardwood, firewood, fresh, firewood, etc. as raw materials are particularly preferable. In particular, it is more preferable to use Binchotan charcoal obtained using swallows. This Bincho charcoal is produced in Kishu, Tosa, etc., and has a structure with many holes. This is presumed to be related to the structure of the plant before carbonization, but because it is such a structure, although it is a very hard material, the necessary miniaturization for ink jet can be made relatively easy. . Bincho charcoal has a high carbon content, so it is easy to obtain a black feeling when used as an ink. Bincho charcoal is also a material that has been used for foods and has undergone a long culture. Therefore, it is also a valuable material that provides a sense of security for use in foods. Bincho charcoal is a material having a lower electrical resistance than that of Takesumi, and is a material that is less susceptible to static electricity in ink production and easy to handle.

  Since carbon powder pigments such as Bincho charcoal are generally obtained in a lump shape, they are coarsely pulverized with a pulverizer and then refined for easy dispersion. As such a miniaturization method, various general-purpose pulverizers by mechanical impact can be used. For further miniaturization, it is desirable to use a fine pulverizer such as a jet mill. In order to obtain inkjet ink, the finely pulverized carbon powder pigment is used and dispersed in the edible resin.

  Since it is used as a material for inkjet ink, the carbon powder pigment dispersed in the edible resin preferably has an average particle size of 0.01 μm or more and 10 μm or less. When the average particle diameter is larger than 10 μm, it takes too much time to sufficiently disperse the edible resin. In addition, the characteristics of the edible resin may be changed due to excessive heat. If the average particle diameter of the carbon powder pigment is smaller than 0.01 μm, there arises a problem that the printing density is lowered.

  When dispersing into edible resin, a method of rolling and dispersing charcoal pigment and edible resin in a plate shape between two rolls, rolling a high viscosity mixture of charcoal pigment and edible resin with three rolls And a method for dispersing the mixture in a medium viscosity state with a high-speed agitator mill, a method for applying an impact by a ball mill with carbon powder pigment and edible resin in a state where the solvent content is reduced, and the like. Can do. However, from the aspect of mixing with the resin solution in the dispersion, dispersion using a horizontal sand mill using zirconia beads or the like as a dispersion medium is preferable.

  When an ink is prepared from the carbon powder pigment and the edible resin mixed as described above, the average particle diameter of the carbon powder pigment is preferably 0.05 μm or more and 3 μm or less. Furthermore, it is more preferable to disperse particles having an average particle diameter of 1 μm or less. Such adjustment of the average particle diameter can be performed by a horizontal sand mill. That is, when the average particle diameter of the carbon powder pigment is larger than 3 μm, sedimentation during storage of ink occurs remarkably, and ink sedimentation or clogging easily occurs in the printer piping system. Moreover, it is not preferable to make the average particle diameter finer than 0.05 μm because it requires unnecessary dispersion energy, and it is not preferable in terms of inducing transparency. With such an ink containing a carbon powder pigment having an average particle diameter of 0.05 to 3 μm, good opacity and black color reproduction can be achieved. About the average particle diameter of the carbon powder pigment | dye disperse | distributed at the time of ink preparation, it can measure with the particle size distribution analyzer of various systems using a laser beam, such as a light-scattering method.

  The carbon powder pigment is related to the content by weight of other components in the present invention, but is preferably contained in the ink in the range of 1 to 20 parts by weight. Furthermore, Preferably it is 1-5 weight part. If the content is less than 1 part by weight, the print density becomes insufficient. When the content of the carbon powder pigment exceeds 20 parts by weight, poor dispersion and continuous printability are deteriorated. In particular, the stability tends to deteriorate in continuous recording. Moreover, there is a possibility that a problem of insufficient fluidity in the ink piping system in the printer may occur.

"Shellac resin"
The shellac resin used in the present invention is an edible resin obtained by refining a resinous substance derived from the silkworm, which is a mixture of many types of resin acids and esterified products thereof, waxes, pigments, etc. An alcohol-soluble type is particularly preferably used. This shellac resin contributes to the dispersion of the carbon powder pigment used in the present invention and fixing with water resistance, and also has a function of increasing the viscosity of the ink by dissolving in alcohol. The shellac resin is also soluble in a water / alcohol mixed solvent. Thus, it contributes as a preferable binder also in the point which can be used for the solvent which mixed water partially.

In the case where the shellac resin is partially mixed with water, the pH of the ink is preferably adjusted to an alkali side of 7.5 to 10.5 in order to maintain stable solubility. When the pH of the ink is lower than 7.5, a part of the shellac resin is easily precipitated. On the other hand, when the pH of the ink exceeds 10.5, the odor in the printer or during printing becomes a problem.
The pH adjuster for adjusting the pH of the ink within the above range is preferably a food additive and a component that volatilizes after printing from the viewpoint of water resistance. For example, ammonium hydroxide, ammonium carbonate, ammonium chloride Etc. Especially, it is preferable to adjust pH using ammonium hydroxide or ammonium carbonate from a viewpoint from which a residue does not become a problem.

  In the ink-jet ink of the present invention, by using a food-addable resin, even if it is immersed in water or rubbed, it can have water resistance and friction resistance that can suppress the dissolution of the recorded ink as much as possible. As such a food additive ability resin, not only the above-mentioned shellac resin, but also danmar resin, copal resin, etc. are easy to use because of their high solubility in alcohol solvents. In addition, a water-soluble resin can be used. As such a water-soluble resin, for example, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, methylcellulose, crystalline cellulose, gelatin, casein, soybean protein, gum arabic cyclodextrin and the like can be used as part of the resin depending on the type of solvent. it can.

"Cellulose resin"
In the present invention, a cellulose resin is used in combination with the shellac resin described above. This cellulosic resin is used by dissolving in water alone or in a mixed solvent of water and alcohol.
In addition, by dispersing carbon powder pigment in an aqueous solution of cellulose resin in advance before dispersion in shellac resin and then dispersing it in shellac resin solution, good dispersion stability can be maintained. In order to maintain this dispersion stability satisfactorily, a cellulosic resin having solubility in water and alcohol is suitable, and hydroxypropyl cellulose having high solubility in both water and alcohol is preferable.
The cellulose resin can have various molecular weights, but it is preferable to use a low molecular weight in view of suitability for dispersion and viscosity. In particular, it is more preferable to use a 2 wt% aqueous solution at 20 ° C. having a molecular weight exhibiting a viscosity of 1 to 7 mPa · s.
Thus, in order to disperse the carbon powder pigment in the cellulose resin in advance, the carbon powder pigment is dispersed in a resin solution obtained by dissolving the cellulose resin in water alone or in a mixed solvent of water and alcohol. At this time, as a liquid for dissolving the cellulose resin, a solvent containing 50% by weight or more of water and less than 50% by weight of ethanol is used. When the ethanol content in the solvent is 50% by weight or more, the dispersion of the carbon powder pigment in the solvent becomes unstable. In particular, the dispersion stability when dispersed in the shellac resin solution in the next second step is lowered, and further, the dispersion is easily broken when a conductive agent is added.

In the present invention, the resin to which food can be added is preferably contained in the range of 1 to 20% by weight, preferably 2 to 15% by weight of the total ink. If the resin content is less than 1% by weight, preferably less than 2% by weight, an ink with an appropriate viscosity cannot be obtained. Further, it is difficult to obtain sufficient adhesion to the recording object. On the other hand, if it exceeds 20% by weight, preferably 15% by weight, the viscosity of the ink becomes too high, the fluidity at low temperature becomes insufficient, and the stability during recording of the ink jet printer also decreases.
In addition, when 2 to 5 parts by weight of a cellulose resin is used with respect to 10 parts by weight of the carbon powder pigment, excellent dispersibility is obtained. When the content of the cellulose resin is less than 2 parts by weight, the carbon powder pigment cannot be sufficiently dispersed. When the content of the cellulose resin exceeds 5 parts by weight, the solubility of the resin itself is high. Insufficient viscosity may cause problems such as excessive viscosity during dispersion.

"Ink solvent"
The inkjet ink of the present invention can contain one or more solvents. The solvent can be used in an amount of 50 to 90% by weight of the total ink. In the present invention, a large amount of ethanol that is superior in dryness is used. In the ink of the present invention, an alcohol ink containing 50% by weight or more of ethanol in the total amount of the ink is a prescription suitable for a dry and water-resistant ink. The ethanol that can be used in the present invention is food-grade fermented ethanol or denatured ethanol.
Moreover, in the inkjet ink of this invention, although related with the content part weight of another component, 3-20 weight part of water is contained. This water dissolves the cellulosic resin in the dispersion of the carbon powder pigment, and is used for the dispersion of the carbon powder pigment. Further, in the ink formulation (second step), it is used to increase the solubility of the conductive agent for adjusting the conductivity according to the suitability of the printer and to obtain a desired conductivity. Although it is used in the ink with the content as described above, when the content of water is less than 3 parts by weight, the dispersion stability of the carbon powder pigment cannot be obtained. On the other hand, if the water content is more than 20 parts by weight, the drying property is deteriorated, and the “quick drying” characteristic for ethanol ink cannot be obtained.

"Wetting agent"
Further, as the solvent, a wetting agent such as propylene glycol may be used in order to adjust the drying property at the nozzle as long as the drying property during recording is not deteriorated. Such a wetting agent serves to adjust the drying property of the ink and the ink viscosity. Further, depending on the background of the recording material, the effect of adjusting the permeability is also suitable for the purpose of use. When such propylene glycol is used in the range of 0 to 10% by weight of the whole ink, it is possible to appropriately permeate the recording object and adjust the drying. When the content of propylene glycol exceeds 10% by weight, the desired improvement in drying properties cannot be achieved.

"emulsifier"
In the present invention, an emulsifier that can be added to food can be further included as an ink component. Examples of such an emulsifier include sorbitan fatty acid ester, glycerin fatty acid ester, sucrose fatty acid ester, and lecithin. These emulsifiers are edible and excellent in aqueous stability, and contribute to the dispersion stability of the carbon powder pigment in the ink.
These emulsifiers are preferably used in an amount of 5% by weight or less based on the solubility in an alcohol solvent, and a sufficient effect can be obtained by using the emulsifier within the range.
Among these emulsifiers, the nonionic active agent is suitable for ink HLB depending on the type of the recording object. Therefore, when the recording object is a packaging film, HLB 8 to 16 are also used for fat and oil content. For foods with a large amount of ink, the ink adjustment such as HLB1-2 is suitable for recording.

"Conducting agent"
The ink-jet ink of the present invention can be used for both continuous-type ink-jet printers and on-demand-type ink-jet printers. However, in the case of inks used for continuous-type ink-jet printers, the conductivity depending on the printer used is used. Rate adjustments are made. A conductive agent is used to adjust the conductivity.
As such a conductive agent, those approved as food additives are used, and examples thereof include sodium lactate, sodium acetate, and pantotensan sodium. Among these, sodium lactate dissolves well in an alcohol-containing solvent, and can achieve the role of maintaining the conductivity of ink droplets in a printer in a small amount.
Although the addition amount of a electrically conductive agent is related with the content part weight of another component, it is preferable that it is 0.2-2.0 weight part. By using within this range, the conductivity of the ink can be adjusted to an appropriate level of about 0.5 m to 5 mS / cm. Adjustment within a small amount is preferable even within the above range. When the addition amount of the conductive agent exceeds 2.0 parts by weight, there is a possibility of causing aggregation of the dye.

Since the ink-jet ink of the present invention contains ethanol or contains ethanol as a solvent main component, the drying property is improved as compared with a water-based ink containing 50% by weight or more of water as a whole. Further, even a non-permeable material can form a recording portion having good water resistance, and depending on the recording system, high-speed variable information can be printed.
The ink of the present invention can be particularly preferably used for a material that comes into contact with food directly or a packaging material for food. Examples of such packaging materials include plastic materials such as polypropylene, polyethylene, polyamide, and polyethylene terephthalate that have been surface-treated as necessary, or nonwoven fabrics, paper, and the like.

  Furthermore, the ink of the present invention is composed entirely of those recognized as food materials and food additives, and is also effective for food design, decoration, high quality data display, quality traceability, etc. It becomes. As the design and its data, production place, harvest date and time, producer, date, special symbol, character image, etc. can be recorded. These notations can also give reliability to the distribution form of the product as a reliable display method of the route.

  Examples of foods on which the inkjet ink of the present invention is recorded include gums, candies, biscuits, cookies, buns, chocolates, and the like. Also, for example, it can be recorded in fruits such as oranges, apples, watermelons, melons, mangoes, strawberries, peaches, vegetables, processed meats, and the like. It is also possible to record health foods on tablets and the like. In addition, packaging materials for packaging these foods are also subject to recording. Alternatively, it can be recorded on food packaging materials such as bread wraps, food trays, lunch boxes, packs, etc., or splits, toothpicks, skewers, etc.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Example 1]
In preparing the inkjet ink of this example, a resin solution, a dispersion, a shellac solution, and an ink were prepared.
First, as “preparation of resin solution preparation”, 3 parts by weight of hydroxypropylcellulose (2% by weight aqueous solution, 20 ° C., 2.5 mPa · s) was dissolved in 87 parts by weight of water (first solution) to prepare hydroxypropylcellulose. An aqueous solution (resin solution) was obtained.
Next, as “preparation of dispersion”, 90 parts by weight of the aqueous hydroxypropyl cellulose solution and 10 parts by weight of Bincho charcoal derived from swallow are mixed to prepare a mill base, and then a horizontal mill containing zirconia beads is prepared. For 2 hours to obtain a dispersion 1 having an average particle size of Bincho charcoal of 0.34 μm (first step, see Table 1 described later).
Subsequently, as “preparation of shellac solution”, shellac resin was added to 99 ° fermented ethanol (second solvent) and stirred to obtain an ethanol solution of 25 wt% shellac resin (25% shellac solution).
Then, as “preparation of ink”, to 20 parts by weight of dispersion 1, 28 parts by weight of 25% shellac solution, 1 part by weight of ammonium carbonate, 1 part by weight of 50% by weight sodium lactate aqueous solution, and 50 parts by weight of ethanol were added, Bincho charcoal in dispersion 1 was refined and further dispersed with a horizontal mill (second step, see Table 2 described later). The resulting dispersion was designated as No. It filtered with the filter of 63. Subsequently, it filtered with the filter of 0.8 micrometer of opening, and obtained the inkjet ink.

[Example 2]
Instead of 20 parts by weight of Dispersion 1, 10 parts by weight of Dispersion 2 shown in Table 1 below (Bumecho charcoal) was used, and the amount of ethanol added in the second step was increased by 10 parts by weight. Except for the above, an ink-jet ink was prepared in the same manner as in Example 1.

[Example 3]
Instead of Dispersion 2, Dispersion 3 (Umekake Bincho charcoal) shown in Table 1 below was used, the amount of shellac solution used in the second step was reduced by 1 part by weight, and the amount of ethanol was increased by 1 part by weight. Except that, an ink-jet ink was prepared in the same manner as in Example 2.

[Example 4]
An ink-jet ink was prepared by treating in the same manner as in Example 2 except that instead of Dispersion 2, Dispersion 4 shown in Table 1 below was used.

[Example 5]
Implemented except that dispersion 5 (takesumi) shown in Table 1 below was used instead of dispersion 2, and the amount of ethanol added in the second step was reduced by 5 parts by weight and 5 parts by weight of propylene glycol was added. An ink-jet ink was prepared by treating in the same manner as in Example 2.

[Example 6]
Instead of Dispersion 2, Dispersion 6 shown in Table 1 below (Bumecho charcoal) was used, the amount of shellac solution used in the second step was increased by 2 parts by weight, and the amount of ethanol was 2.3 wt. An ink jet ink was prepared in the same manner as in Example 2 except that the amount was reduced and the amount of 50% sodium lactate was increased by 0.3 part by weight.

[Example 7]
Instead of Dispersion 6, Dispersion 7 shown in Table 1 below (Bumecho charcoal) was added, 0.5 parts by weight of glycerin fatty acid ester was added, and the amount of ethanol added in the second step was 0.5. An inkjet ink was prepared in the same manner as in Example 6 except that the weight part was reduced.

[Example 8]
Instead of Dispersion 7, Dispersion 8 shown in Table 1 below (Bumecho charcoal) was added, 0.5 part by weight of sorbitan fatty acid ester was added, and the amount of 50% sodium lactate was 0.2 part by weight. An ink jet ink was prepared in the same manner as in Example 7 except that the amount of ethanol added in the second step was reduced by 0.7 parts by weight.

[Example 9]
Instead of 10 parts by weight of Dispersion 6, 15 parts by weight of Dispersion 9 shown in Table 1 below (Bumecho charcoal) was used, and the amount of 50% sodium lactate was increased by 0.2 parts by weight. Inkjet ink was treated in the same manner as in Example 6 except that the amount of ammonium was increased by 0.5 parts by weight, 3 parts by weight of propylene glycol was added, and the amount of ethanol added in the second step was reduced by 8.7 parts by weight. Was prepared.

[Comparative Example 1]
Using 20 parts by weight of dispersion 1A (Arashino Bincho charcoal) shown in Table 3 below, 0.5 parts by weight of glycerin fatty acid ester, 2 parts by weight of sodium lactate, and 77.5 parts by weight of purified water, Inkjet ink was produced.

[Comparative Example 2]
Using 25 parts by weight of dispersion 2A (Arashino Bincho charcoal) shown in Table 3 below, glycerin fatty acid ester and purified water were omitted, and 40 parts by weight of 25% shellac solution and 33 parts by weight of ethanol were added. Except that, an inkjet ink was prepared in the same manner as in Comparative Example 1.

[Comparative Example 3]
Using 10 parts by weight of dispersion 3A (Arashino Bincho charcoal) shown in Table 3 below, 1 part by weight of ammonium carbonate and 5 parts by weight of purified water were added, and the amount of 25% shellac solution was increased by 10 parts by weight. Except that, an inkjet ink was prepared in the same manner as in Comparative Example 2.

[Comparative Example 4]
An inkjet ink was prepared in the same manner as in Comparative Example 3, except that 20 parts by weight of dispersion 4A shown in Table 3 below was used, and the amount of 25% shellac solution was reduced by 10 parts by weight. Prepared.

[Comparative Example 5]
Using 20 parts by weight of dispersion 5A shown in Table 3 below, refined water is omitted, the amount of 25% shellac solution is increased by 10 parts by weight, and the amount of ethanol is reduced by 5 parts by weight. Except that, an inkjet ink was prepared in the same manner as in Comparative Example 4.

[Comparative Example 6]
Using 20 parts by weight of Dispersion 6A shown in Table 3 below, ammonium carbonate is omitted, the amount of 25% shellac solution is reduced by 10 parts by weight, and the amount of sodium lactate is 2 parts by weight. An inkjet ink was prepared in the same manner as Comparative Example 5 except that the amount of ethanol was increased and the amount of ethanol was increased by 8 parts by weight.

[Comparative Example 7]
Using 20 parts by weight of dispersion 7A (Takesumi) shown in Table 3 below, adding 1.5 parts by weight of ammonium carbonate, reducing the amount of sodium lactate by 2 parts by weight, and increasing the amount of ethanol by 0.5 parts by weight An inkjet ink was prepared in the same manner as in Comparative Example 6 except that.

[Comparative Example 8]
Using 20 parts by weight of Dispersion 8A shown in Table 3 below, the amount of 25% shellac solution is reduced by 12 parts by weight, the amount of ammonium carbonate is reduced by 0.3 parts by weight, An inkjet ink was prepared in the same manner as in Comparative Example 7, except that the amount was increased by 12.3 parts by weight.

[Comparative Example 9]
An inkjet ink was prepared in the same manner as in Comparative Example 8 except that 20 parts by weight of Dispersing Element 9A shown in Table 3 below was used.

The prescriptions of dispersions 1 to 9, 1A to 9A used in the above Examples and Comparative Examples, the prescriptions of inkjet inks prepared in Examples 1 to 9 and Comparative Examples 1 to 9, and various physical properties are shown in the following table. Table 1 relates to the formulations of Dispersions 1-9 used in Examples 1-9, Table 2 relates to Examples 1-9, and Table 3 shows Dispersions 1A used in Comparative Examples 1-9. Table 4 relates to Comparative Examples 1-9.
Of the physical property items shown in the table,
“Redispersibility” was evaluated by the dispersion state at that time after filtering the ink that had been left standing after shaking 20 times.
“Water resistance” was confirmed by the presence or absence of ink dissolution when the printed surface of a printed recording object was moistened with water, the color of water, and the color of tissue paper wiped from the printed surface.
"Adhesion" was confirmed by the presence or absence of peeling when ink was applied to a food grade polyamide film and the coated part was rubbed with a cotton swab.
“Print density” was obtained by printing ink on PPC paper and measuring the reflection density of the printed portion with a Macbeth reflection densitometer (Model RD918 manufactured by GretagMacbeth).
“Continuous ejection” refers to troubles when the ink prepared as described above is loaded into a continuous ink jet printer (model KGK JET CCS-N manufactured by Kishu Giken Kogyo Co., Ltd.) and a continuous printing test is performed ( Nozzle clogging, defective printing (abnormal font), abnormal ejection pressure, etc.). With this continuous ink jet printer, confectionery, apples, mango, food-use polyamide films, and tablets were printed, and printed matter with a good black feeling was obtained.
“Printing performance in a high temperature environment” evaluated the state of printing results when a printing test was performed with an ink jet printer in an environmental chamber maintained at a room temperature of 45 ° C.
“Printing performance in a low-temperature environment” evaluated the state of printing results when a printing test was performed with an inkjet printer in an environmental chamber maintained at a room temperature of 5 ° C.

The viscosity (20 ° C., mPa · s) of the ink-jet ink is measured using a viscometer (EH cone type) manufactured by TOKI Sangyo Co., Ltd., the pH is measured using a pH meter, and the conductivity (mS / cm) is Horiba. It measured using the company-made conductivity meter. The average particle diameter of the carbon powder pigment in the ink was measured by the median diameter (d50) using a particle size distribution meter (UPA type) manufactured by Nikkiso Co., Ltd.
In each table, the numerical value indicating the prescription represents parts by weight. Moreover, the numerical value shown in () in Table 1 and Table 3 has shown the weight part in the ink whole quantity when an inkjet ink is prepared. The numerical values shown in parentheses in the column of 25% shellac solution in Tables 2 and 4 indicate the parts by weight of the shellac resin itself in the total amount of ink. In Tables 1 and 3, HPC represents hydroxypropyl cellulose, and those given (* 1) are those in which the viscosity of a 2 wt% HPC aqueous solution is 2.5 mPa · s. Those marked with (* 2) are those in which the viscosity of the 2 wt% HPC aqueous solution is 3.85 mPa · s. In Table 3, CMC represents carboxymethylcellulose.

As shown in Tables 1 to 4 above, the inkjet inks of Examples 1 to 9 are gathered without greatly varying between Examples with respect to the average particle diameter, viscosity, pH, and conductivity. Is also an appropriate range for product inks. However, the ink jet ink of Example 5 using bamboo stain as a carbon powder pigment has a slightly larger average particle size than the other examples, which results in a somewhat lower printing density. However, these values are also within the appropriate range. In addition, the inkjet inks of Examples 1 to 9 can satisfy all the items regarding redispersibility, water resistance, adhesion, printing density, 45 ° C environmental printing performance, 5 ° C environmental printing performance, and continuous ejection properties. It was a result (refer Table 2). These are because the ink-jet inks of Examples 1 to 9 contain charcoal pigment, shellac resin, cellulosic resin, ethanol, and water, and each component is blended in a predetermined range. In addition, a dispersion is obtained by dispersing a carbon powder pigment in a resin solution in which a cellulose resin is dissolved in a water / ethanol solvent, and this dispersion is mixed with a shellac resin ethanol solution to disperse the carbon powder pigment. This is because it was manufactured in
In the process of continuous discharge for a long period in the continuous discharge test, the concentration of ink due to the evaporation of the alcohol from the ink is 90% by weight of ethanol and 10 parts by weight of water. A solution obtained by dissolving 1.1 parts by weight of ammonium carbonate in an ethanol / water mixture was used as a diluent. The pH of this diluted solution was 10.4. At this time, the pH of the ink is 9 or more and the alkali side, so there is no decrease in the solubility of the shellac resin in the ink, the stability of the ink is ensured, and the long-term continuous printing stability can be maintained. ing.

 On the other hand, the inkjet ink of Comparative Example 1 did not use shellac resin because the solvent was not ethanol but water alone, but the redispersibility with the ink was good. However, water resistance and adhesion were not good. Ink jet ink of Comparative Example 2 has CMC dissolved in a large amount of ethanol in Dispersion 2A, so that the dispersion state of the bamboo in the ink is not good (redispersibility), and thus the average particle size cannot be measured. It was. Further, the water resistance and adhesion with the ink were not good. Since the inkjet inks of Comparative Examples 3 and 4 used shellac resin instead of cellulose resin in dispersions 3A and 4A, the water resistance and adhesion with the ink were good. However, since a large amount of ethanol was used in dispersions 3A and 4A, redispersibility was poor. In the inkjet ink of Comparative Example 5, since Bincho charcoal was dispersed in water without using any resin in Dispersion 5A, the redispersibility with the ink was poor and the average particle size could not be measured. In the inkjet ink of Comparative Example 6, Bincho charcoal and HPC were dispersed in ethanol without using water at all in the dispersion 6A, so the redispersibility with the ink was poor and the aggregated state was not able to be measured. Since the inkjet ink of Comparative Example 7 uses charcoal in the dispersion 7A, the viscosity of the ink increased with time, and the viscosity became out of specification of the product ink as well as the deterioration of redispersibility. Ink-jet inks of Comparative Examples 8 and 9 are dispersed in 8A and 9A without using ethanol, but Bincho charcoal and HPC are dispersed in water. Aggregation occurred and redispersibility was not good.

Claims (8)

An ink-jet ink comprising charcoal pigment, shellac resin, cellulosic resin, ethanol, and water, all of which are approved as food additives. The inkjet ink according to claim 1, further comprising a conductive agent approved as a food additive. All are approved as food additives, 1 to 20 parts by weight of carbon powder pigment, 1 to 20 parts by weight of shellac resin, 0.1 to 10 parts by weight of cellulose resin, 40 to 90 parts by weight of ethanol, 3 to 20 water An inkjet ink comprising parts by weight and 0.1 to 2 parts by weight of a conductive agent. Bincho charcoal 1-20 parts by weight, shellac resin 1-20 parts by weight, hydroxypropylcellulose 0.1-10 parts by weight, ethanol 40-90 parts by weight, water 3-20 parts by weight, and sodium lactate 0.1-2 parts by weight Ink-jet ink comprising a part. The inkjet ink according to any one of claims 1 to 4, wherein the carbon powder pigment is a powder of Bincho charcoal. The inkjet ink according to any one of claims 1 to 5, further comprising a pH adjuster approved as a food additive. A method for producing an inkjet ink according to claim 1 or claim 3, wherein a carbon powder pigment is added to a resin solution in which a cellulose-based resin is dissolved in a first solvent containing 50% by weight or more of water as a whole. The dispersion obtained in the first step is further dispersed in a first step of obtaining a dispersion by dispersion and a shellac solution in which a shellac resin is dissolved in a second solvent containing 50% by weight or more of ethanol as a whole. And a second step for producing the ink-jet ink. When recording on a food-related recording object with an inkjet printer using the inkjet ink according to claim 3, the inkjet ink is diluted with a diluting solvent containing ethanol, water, and ammonium carbonate and used in the inkjet printer. A method of using an inkjet ink characterized by