Edible ink composition

Abstract

The present invention provides an edible ink composition not containing titanium oxide. The edible ink composition not containing titanium oxide is provided by mixing magnesium carbonate, magnesium hydroxide, or the like as a whitening agent, an alcohol-soluble binder, an alcohol as a solvent, and an optional additive. Since the edible ink composition of the present invention uses a white pigment such as magnesium carbonate, which has been safely used without health problems, instead of titanium oxide, it can be used for solid foods, solid pharmaceutical preparations, and the like. It is particularly useful as an ink printed on the surface of capsules, tablets, and caplets by offset printing.

Description

Technical Field

[0001] This invention relates to an edible ink composition that is free of titanium dioxide. The invention relates to an edible ink composition comprising a whitening agent selected from the group consisting of: magnesium carbonate (including basic magnesium carbonate, light magnesium carbonate, and heavy magnesium carbonate), magnesium hydroxide, magnesium stearate, calcium hydroxide, calcined calcium, calcium stearate, tricalcium phosphate, carnauba wax, dolomite, bentonite, agar, activated clay, or mixtures thereof. The edible ink composition further comprises an alcohol-soluble film-forming polymer (referred to herein as an alcohol-soluble binder) as a binder and an alcohol as a solvent.

[0002] This invention particularly relates to an edible ink composition comprising a white pigment, in particular magnesium carbonate, as a whitening agent. The invention also relates to an edible ink composition suitable for printing, particularly offset printing, on the surfaces of solid foods and pharmaceutical solid dosage forms, such as confectionery, candy, tablets, capsules, etc., and a method for preparing the same.

[0003] Furthermore, the present invention relates to a method for offset printing using an edible ink composition containing the aforementioned whitening substances, and to solid food and solid pharmaceutical preparations (e.g., tablets, capsules, and granules) printed with the edible ink composition. Background Technology

[0004] Solid food products such as confectionery or sweets and solid pharmaceutical preparations such as tablets, capsules, and pouches typically have symbols, characters, and / or patterns printed on their surfaces to identify the product. In particular, printing on solid pharmaceutical preparations is widely used as a means of conveying various information, such as product names, code numbers, company names (such as their symbolic markings), etc.

[0005] Traditionally, printing on solid pharmaceutical preparations and solid food products has been done using edible printing inks, which contain pigments mixed or dispersed in a carrier, such as titanium dioxide, ferric oxide and edible aluminum lake, in which shellac is dissolved in an alcoholic organic solvent (Patent Document 1 and Patent Document 2).

[0006] Shellac is a thermosetting resin produced by the lac insect (Laccifer lacca) and is harmless to humans. Because of its ability to adhere to surfaces, it is used as a binder for edible inks in many countries.

[0007] White pigments such as water-insoluble calcium salts (e.g., calcium phosphate, calcium oxide, and calcium carbonate) and titanium dioxide are used to whiten edible ink compositions. Titanium dioxide, in particular, has a high refractive index and excellent hiding power and tinting strength. Therefore, it is not only widely used as a white pigment but also in combination with colorants of colors other than white.

[0008] However, in 2020, the European Union (EU) classified titanium dioxide as a "carcinogenic category 2" and banned its use in the European food market starting in 2022.

[0009] (https: / / www.jetro.go.jp / biznews / 2022 / 08 / 817e100825b5eb14.html) Furthermore, in the EU, it is said that the use of titanium dioxide in pharmaceuticals will be banned around 2025. Therefore, there is an urgent need to develop a titanium dioxide-free, edible white ink composition for use in the food and pharmaceutical industries.

[0010] As an example of using other materials to replace titanium dioxide in the field of edible inks, Patent Document 3 describes an edible ink composition comprising a yellow oil-based natural coloring material, characterized by 10%-15% by weight of the aforementioned oil-based natural coloring material, 15%-40% by weight of edible oil or fat as a carrier, and 50%-70% by weight of eggshell calcium. The main component of eggshell calcium is calcium carbonate.

[0011] Patent document 4 describes an edible ink composition for screen printing, characterized by containing water, alcohol, stabilizer, sugar and / or surfactant, and an edible, water-insoluble inorganic fine powder with covering power, wherein inorganic calcium salts, titanium dioxide, magnesium carbonate, and shell powder are listed as examples of water-insoluble white inorganic fine powders used in the ink. A thickener is used as a stabilizer in this ink composition, and, if necessary, a resin and an edible polymer are used.

[0012] These stabilizers are water-soluble and act as binders or physical property improvers in the inks, enabling the compositions of the present invention to exhibit the various properties necessary for screen printing inks. However, the aforementioned ink compositions, due to the presence of water as a solvent, have a slow drying rate and therefore cannot be used for offset printing, which is performed at high speeds.

[0013] Patent document 5 describes an edible ink formulation comprising: Solvent, binder, and triangular calcium carbonate particles, The solvent comprises one or more C2 to C6 alcohols selected from the group consisting of isopropanol, 1-propanol, ethanol, 1-butanol, 3-methyl-1-butanol, 2-butanol, hexanol, and combinations thereof, wherein the triangular-faceted calcium carbonate particles are present in an amount of about 15% to about 35% by weight, and wherein the edible ink formulation, when prepared into a dry film, exhibits a reflectance of about 30% to about 75% in the wavelength range of about 440 nm to about 700 nm, and when the dry film is made from a wet film with a thickness of about 13 μm or less, it exhibits a luminance of at least about 40 L under the CIE standard light source D65. Value. Patent document 6 describes an edible ink formulation comprising triangular-faceted calcium carbonate particles, an alcohol, and an aqueous solvent, wherein the edible ink formulation, when applied as a film, exhibits a print durability score of less than 70.

[0014] These publications disclosed edible inks containing triangular-faceted calcium carbonate particles as a white pigment in place of titanium dioxide, but did not teach any other whitening agents.

[0015] Patent document 7 describes an ink composition containing a polymer, a coloring component, and a solvent or dispersion medium, which can be incorporated into edible materials. It lists hydroxypropyl cellulose, polyvinylpyrrolidone, hydroxypropyl methylcellulose, etc., as polymers; calcium carbonate, magnesium carbonate, magnesium oxide, magnesium stearate, calcium stearate, etc., as coloring components; and one or more solvents selected from water, ethanol, and acetone as solvents. However, this ink composition is used to form a transfer layer in a laser transfer film and is unrelated to offset printing inks.

[0016] Patent document 8 describes an inkjet printer ink containing resin and pigment, wherein the resin comprises 15 to 50 parts by weight relative to 1 part by weight of pigment, the resin contains shellac, the pigment contains charcoal powder dye, and the pigment comprises 0.05% to 0.7% by weight, the ink having a pencil hardness of 2B to 4H after drying, and the reflectance density of the ink after drying into a film is 0.1 to 0.3, and it also lists examples of titanium dioxide and calcium carbonate as other pigments.

[0017] Patent document 9 describes a tablet with a printed surface consisting of printed dots made by a dried coating of inkjet ink containing a dye, hydroxypropyl cellulose with a molecular weight of 10,000 to 150,000, and a solvent containing ethanol and water as essential components, and each printed dot is concave, and provides an example of titanium dioxide as the dye.

[0018] These documents do not disclose any white pigments other than titanium dioxide and calcium carbonate, and all of them are ink compositions specifically for inkjet printers and cannot be used for offset printing.

[0019] Existing technical documents Patent documents Patent document 1: JPS47-31706A Patent document 2: JP2020-29537A Patent document 3: JPH8-308533A Patent document 4: JPS63-63363A Patent document 5: US2023 / 0217950A Patent document 6: US 2021 / 259275A Patent document 7: JP2015-091647A Patent document 8: JP2014-240386A Patent document 9: JP2015-218144A Summary of the Invention

[0020] The problem to be solved by the present invention The first object of the present invention is to provide an edible ink composition suitable for printing on the surface of solid food or solid pharmaceutical preparations, which does not have the carcinogenic problems of titanium dioxide.

[0021] A second objective of this invention is to provide a quick-drying, edible ink composition that can be used for high-speed printing via offset printing.

[0022] Solution to the problem The inventors of this invention have conducted extensive research to find a novel edible colorant that can replace titanium dioxide in white inks, and have discovered that printing inks containing magnesium carbonate as a whitening agent can be used for printing with clear legibility. Magnesium carbonate is a chemical substance traditionally used as a pharmaceutical additive in oral and topical medicines, and is also used in various foods to supplement or fortify the essential mineral magnesium. Therefore, it can be safely used as a whitening agent, particularly as a white pigment in edible ink compositions.

[0023] Furthermore, the inventors have discovered that a group of whitening agents, such as magnesium hydroxide, magnesium stearate, calcium hydroxide, calcined calcium, calcium stearate, carnauba wax, tricalcium phosphate, dolomite, bentonite, agar, and activated clay, also provide prints with clear distinguishability, just like magnesium carbonate.

[0024] The inventors of this invention have discovered that an edible ink composition containing the aforementioned whitening agent can be used for offset printing by using an alcohol-soluble film-forming polymer as an alcohol-soluble binder and using alcohol as a solvent. The alcohol-soluble film-forming polymer and alcohol impart a rapid drying speed to the ink.

[0025] These edible ink compositions can be printed at high speeds on the surfaces of solid pharmaceutical preparations and solid foods using offset printing.

[0026] In addition to the aforementioned white pigment, the edible ink composition of the present invention also contains a binder and a solvent, and may also contain optional additives such as humectants (drying rate regulators) and dispersants. Even in the presence of these additives, the intended use of the ink for offset printing can be fully achieved.

[0027] (definition) As used herein, the term edible ink composition according to the present invention refers to a liquid composition comprising a whitening agent, a binder, and a solvent, and optionally additives, wherein all components are edible. The edible ink composition may also be referred to herein as the term "ink composition" or simply the term "ink".

[0028] The solids remaining after the edible ink composition has dried, i.e. after the volatile components have evaporated, are generally referred to herein as “dried edible ink composition” or simply “dried ink”.

[0029] Unless otherwise stated, “% by weight” refers to the ratio of the weight of the component to the weight of the edible ink composition (i.e., the undried ink).

[0030] Unless otherwise stated, the unit "um" is the same as the unit "μm", which means "micrometer".

[0031] As used in this article, the term "room temperature" refers to 20°C to 25°C.

[0032] For propane-1,2,3-triol, all three common names glycerol, glycerin, and glycerine are used as synonyms in this document.

[0033] The present invention is based on the above findings and includes the following aspects.

[0034] [1] An edible ink composition for offset printing, comprising a whitening agent, an alcohol-soluble binder, and a solvent, wherein the edible ink composition is free of titanium dioxide. The whitening agent mentioned herein is selected from the group consisting of: magnesium carbonate, magnesium hydroxide, magnesium stearate, calcium hydroxide, calcined calcium, calcium stearate, carnauba wax, tricalcium phosphate, dolomite, bentonite, agar, activated clay, and mixtures thereof; The alcohol-soluble binder is hydroxypropyl cellulose, polyvinylpyrrolidone, hydroxypropyl methylcellulose, hydroxyethyl cellulose, or a mixture thereof, and The solvent is an alcohol.

[0035] Aspect [2] According to the edible ink composition of aspect [1], wherein the whitening agent is a white pigment and is magnesium carbonate.

[0036] [3] According to the edible ink composition of [1] or [2], wherein after drying the edible ink composition, the amount of whitening agent in the dried ink is 30% to 90% by weight, preferably 50% to 80% by weight, based on the weight of the dried ink.

[0037] Aspect [4] An edible ink composition according to any one of aspects [1] to [3], wherein the solid content of the edible ink composition is from 10% to 90% by weight, preferably from 20% to 50% by weight, based on the weight of the edible ink composition.

[0038] Aspect [5] An edible ink composition according to any one of aspects [1] to [4], wherein the solvent evaporates or evaporates by drying the edible ink composition and is substantially not left in the dried edible ink composition.

[0039] Aspect [6] An edible ink composition according to any one of aspects [1] to [5], wherein the solvent is selected from the group consisting of ethanol, propanol, isopropanol and butanol, preferably ethanol or butanol, even more preferably ethanol.

[0040] Aspect [7] The edible ink composition according to any one of aspects [1] to [6] comprises a colorant having a color other than white as an additional component.

[0041] Aspect [8] An edible ink composition according to any one of aspects [1] to [7] comprises an additive as an additional component, said additive being selected from the group consisting of: sorbitol, glycerol, propylene glycol, sucrose, glucose, galactose, fructose, xylitol, maltose, maltitol, trehalose, lactose, alcohol-soluble oligosaccharides, cationic or anionic surfactants, glycerol fatty acid esters, polysaccharides, nonionic surfactants (such as glycerol fatty acid esters, sorbitan fatty acid esters and sucrose fatty acid esters), polycarboxylic acid polymer dispersants, phosphates (such as polyphosphates and hexametaphosphates), and clay minerals having a zeta potential (such as kaolin, halloysite, montmorillonite, diaspore and silica anhydride) and combinations thereof.

[0042] Aspect [9] A printing substrate for offset printing using an edible ink composition according to any one of aspects [1] to [8]; preferably, the printing substrate is a solid food or a solid pharmaceutical preparation; the solid pharmaceutical preparation is preferably a hard capsule, soft capsule, tablet or capsule capsule.

[0043] Aspect

[10] A method for producing an edible ink composition according to any one of aspects [1] to [8], comprising the step of mixing a whitening agent, a binder, a solvent and any optional additional components as components of the edible ink composition, thereby providing the edible ink composition.

[0044] Aspect

[11] A method for printing, the method comprising the step of offset printing an edible ink composition according to any one of aspects [1] to [8] onto a printing substrate.

[0045] The components of the edible ink composition of the present invention are described in more detail below.

[0046] (Whitening agent) In this invention, magnesium carbonate can be used as a whitening agent, i.e., as a white pigment. Magnesium carbonate includes basic magnesium carbonate, heavy magnesium carbonate, and light magnesium carbonate.

[0047] The precipitate obtained by adding sodium carbonate or potassium carbonate to an aqueous solution of magnesium salt is called basic magnesium carbonate (mMgCO3-Mg(OH)2-nH2O) and is commonly referred to as magnesium carbonate.

[0048] The composition ratio of basic magnesium carbonate varies depending on the manufacturing method. The ratio of MgCO3 to Mg(OH)2 is 3 to 5, i.e., m can be 3 to 5, and the ratio of H2O is 3 to 7, i.e., n can be 3 to 7.

[0049] Heavy magnesium carbonate is a pentahydrate salt with a molar mass of 485.65 g / mol. Light magnesium carbonate is a tetrahydrate salt and is called light magnesium carbonate because its composition is lighter than that of heavy magnesium carbonate. Its molar mass is 467.64 g / mol.

[0050] The stronger the light reflection of the particles, the whiter the ink will be, and this amount of reflection can be characterized by the refractive index. Whitening agents, especially white pigments, are preferably substances with a refractive index close to that of titanium dioxide (2.3-2.8: depending on the crystal system). Magnesium carbonate, with a refractive index of 1.52-1.63, is one of the highest refractive indexes among white pigments used in food and medicine.

[0051] From the perspective of preventing the fine markings engraved on the offset printing roller of the printing press from clogging and increasing the amount of light reflection, the preferred particle size of the pigment is 0.1 μm to 30 μm, more preferably 0.1 μm to 20 μm, and even more preferably 0.1 μm to 10 μm.

[0052] From the perspective of particle shape that enhances light reflection, flat particles with a high aspect ratio are superior to blocky or spherical particles that scatter and reflect light in terms of whiteness.

[0053] Furthermore, the inventors have discovered other compounds besides magnesium carbonate that have a strong white color and can be used as suitable whitening agents.

[0054] These are magnesium hydroxide, magnesium stearate, calcium hydroxide, calcined calcium, calcium stearate, tricalcium phosphate (Ca3(PO4)2), dolomite (a double salt in which CaCO3 and MgCO3 are combined in a 1:1 molar ratio), carnauba wax, bentonite, agar, and activated white clay.

[0055] Calcined calcium refers to calcium oxide (CaO). It is produced by baking washed and finely crushed seashells at temperatures exceeding 1000°C for an extended period, followed by further pulverizing the shells into fine particles. It can also be obtained by calcining CaCO3 or Ca(OH)2.

[0056] These whitening agents can be used alone, or in combination of two or more.

[0057] Therefore, the whitening agent is selected from the group consisting of: magnesium carbonate, magnesium hydroxide, magnesium stearate, calcium hydroxide, calcined calcium, calcium stearate, carnauba wax, tricalcium phosphate, dolomite, bentonite, agar, activated clay, and mixtures thereof. Preferably, the whitening agent is a white pigment and is magnesium carbonate.

[0058] In addition to these whitening agents, the edible ink compositions of the present invention may contain other white pigments besides titanium dioxide, which are edible and provide sufficient whiteness to the ink.

[0059] Therefore, another implementation of the whitening agent is a combination of magnesium carbonate and magnesium oxide.

[0060] The particle size of the white pigment described herein has been measured by laser diffraction at a detection wavelength of 650 nm and an emission wavelength of 405 nm. Preferably, this measurement has been performed and can be performed using an aqueous dispersion of the white pigment. Preferably, this measurement has been performed and can be performed at 24°C.

[0061] The particle size distribution has been and can be measured as follows, using magnesium oxide as an example of a white pigment; those skilled in the art can apply this procedure to any white pigment of the present invention: Preparation of aqueous dispersions of magnesium oxide: A sample for measurement was prepared by dispersing an appropriate amount of magnesium oxide in an aqueous solution of sodium hexametaphosphate (0.2 wt%) (Wako Pure Chemical Industries, Ltd.) in an external ultrasonic bath.

[0062] Then, the dispersion is placed in a particle size analyzer, and the particle size distribution is measured while the sample is sonicated by the corresponding ultrasonic device built into the particle size analyzer.

[0063] Measurement device: PARTICA LA-960V2 laser diffraction / scattering particle size distribution analyzer (Horiba Ltd.) Measurement unit: wet Temperature measured: room temperature Light source: LD (laser diode, 650 nm) and LED (light-emitting diode, 405 nm) Particle size standard: volume Particle refractive index: 1.76 (real part), 0.00 (imaginary part) Solvent: 0.2% by weight sodium hexametaphosphate aqueous solution Solvent refractive index: 1.333 In one embodiment, the edible ink composition is free of the white colorant titanium dioxide (TiO2).

[0064] In one embodiment, the edible ink composition is TiO2-free.

[0065] In one embodiment, the edible ink composition does not contain the white colorant calcium carbonate (CaCO3).

[0066] In one embodiment, the edible ink composition is free of CaCO3.

[0067] In one embodiment, the edible ink composition is free of white colorant TiO2 and free of white colorant CaCO3.

[0068] In one embodiment, the edible ink composition is free of TiO2 and CaCO3.

[0069] In one embodiment, the edible ink composition does not contain the white colorant calcium oxide (CaO).

[0070] In one embodiment, the edible ink composition does not contain CaO.

[0071] In one embodiment, the edible ink composition is free of white colorant TiO2 and free of white colorant CaO.

[0072] In one embodiment, the edible ink composition is free of TiO2 and CaO.

[0073] In one embodiment, the edible ink composition does not contain any white coloring agents (also known as white colorants) other than whitening agents and MgO.

[0074] In one embodiment, the edible ink composition does not contain any white coloring agents (also known as white colorants) other than whitening agents.

[0075] (Alcohol-soluble binder) Alcohol-soluble binders, also referred to herein as “binders,” are edible film-forming polymers that are soluble in alcohol. These binders are hydroxypropyl cellulose (HPC), polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), hydroxyethyl cellulose (HEC), or mixtures thereof.

[0076] Preferably, the binder is hydroxypropyl cellulose (HPC), polyvinylpyrrolidone (PVP), or a mixture thereof.

[0077] From the perspective of printing quality, the preferred film-forming polymer is hydroxypropyl cellulose.

[0078] Hydroxypropyl cellulose is a nonionic cellulose ether obtained by treating cellulose (pulp), which is widely found in nature, with sodium hydroxide and then reacting it with an etherifying agent such as propylene oxide. Hydroxypropyl cellulose is used as a pharmaceutical additive in tablets, capsules, and granules, such as a lubricant, coating agent, disintegrant, and binder. Polyvinylpyrrolidone is also used in the pharmaceutical industry in Japan and in the European Union (EU) as a coating agent for pharmaceutical tablets.

[0079] Therefore, there are no safety issues when these substances are used as binders in edible ink compositions.

[0080] (solvent) The solvent is essentially evaporated or volatilized during the drying of the edible ink composition, and does not remain in the dried ink after the edible ink composition has dried, especially after printing the edible ink composition.

[0081] In this invention, alcohol is used as a solvent to enable rapid drying of the edible ink composition. Adding a large amount of alcohol to the edible ink composition reduces the concentration of solid components, thereby increasing the drying speed of the edible ink composition.

[0082] The alcohol is preferably selected from the group consisting of ethanol, propanol, isopropanol and butanol, more preferably ethanol or butanol, and even more preferably ethanol.

[0083] Offset printing is faster than screen printing; for example, hard capsules can be printed at speeds of up to 300,000 per hour. Therefore, the ink compositions used in offset printing require significantly shorter drying times than those used in screen printing. Specifically, the inks are required to dry within 5 seconds of printing.

[0084] Since the vapor pressure of alcohol is much higher than that of water, the edible ink composition of the present invention has the advantage of fast drying speed and therefore can be used for high-speed offset printing.

[0085] The edible ink composition of the present invention may contain one or more of the following additional components: (Moisturizer) The drying rate of edible ink compositions is affected by ambient humidity. When the air is dry, the edible ink composition begins to dry on the printing plate and blanket of the printing press, which may cause the ink in the printed matter to fade.

[0086] To prevent this problem and adjust the drying speed of the edible ink composition, a humectant can be added to the edible ink composition as a possible additional component.

[0087] Sorbitol, glycerin, propylene glycol, sucrose, glucose, galactose, fructose, xylitol, maltose, maltitol, trehalose, lactose, and alcohol-soluble oligosaccharides can be used as humectants. The amount of humectant should be adjusted while inspecting the printed matter. In the case of sugars, the typical amount of humectant is 0% to 3% by weight; in other cases, it is 0% to 20% by weight, with the weight percentage based on the weight of the edible ink composition.

[0088] (Dispersant) In edible ink compositions, dispersants can be added as a possible additional component to stably disperse the pigment in the binder solution. Dispersants can include charged cationic or anionic surfactants, nonionic surfactants such as glycerol fatty acid esters, polyglycerol fatty acid esters, sorbitol fatty acid esters, sucrose fatty acid esters, or polycarboxylate polymer dispersants; phosphates such as polyphosphates and hexametaphosphates; or clay minerals with zeta-tracking properties such as kaolin, halloysite, montmorillonite, and diaspore. Alternatively, the dispersion can be stabilized by dispersing thixotropic agents such as silica anhydride. These substances can also be used in combination.

[0089] The amount of dispersant is from 0% to 10% by weight, where the weight percentage is based on the weight of the edible ink composition.

[0090] (Coloring agent) If a color other than white is required, the desired amount of colorant other than white can be added to the edible ink composition, or it can replace a portion of the white pigment of the present invention.

[0091] Colorants that can be used include pigments and dyes known to those skilled in the art and suitable as components in edible compositions, such as tar-based pigments such as aluminum lake, insoluble colored pigments such as yellow ferric oxide, red ferric oxide, black ferric oxide and carbon black, dyes dissolved in alcohol such as squid ink, or uniformly dispersed dyes.

[0092] The edible ink composition described above may contain one or more additives as other possible components commonly used in printing inks, such as plasticizers, adhesion enhancers, ink gloss agents, and fragrances. Preferably, any other components are edible additives. Even in the presence of these additives, the edible ink composition of the present invention can fully achieve its purpose as a printing ink.

[0093] (Weight ratio of components) Based on the weight of the edible ink composition, the preferred amount of solvent in the edible ink composition is 20% to 89% by weight, more preferably 60% to 80% by weight.

[0094] Based on the weight of the edible ink composition, the preferred amount of binder in the edible ink composition is from 1% to 60% by weight, more preferably from 2% to 20% by weight, or even more preferably from 3% to 10% by weight.

[0095] Based on the weight of the edible ink composition, the typical amount of whitening agent (such as magnesium carbonate) in the edible ink composition is 10% to 60% by weight, more preferably 12% to 40% by weight, and even more preferably 15% to 30% by weight.

[0096] The weight ratio of pigment to binder in the edible ink composition (pigment / binder) is preferably 1 to 10.

[0097] Preferably, after drying, the amount of whitening agent (such as magnesium carbonate) in the edible ink composition is 30% to 90% by weight, preferably 50% to 80% by weight, based on the weight of the dried ink.

[0098] Based on the weight of the edible ink composition, the solid content of the edible ink composition, i.e., the weight of the dried ink after drying, is preferably 10% to 90% by weight, and more preferably 20% to 50% by weight.

[0099] In the edible ink composition, the preferred amount of the sum of any other components is 0% to 25%, preferably 0% to 10%, or even only 0% to 5%; the typical amount is 0% to 10%; % is based on the weight of the edible ink composition.

[0100] The preferred blending ratios of the binder, solvent, whitening agent (such as magnesium carbonate), optionally humectant, and optionally dispersant in the edible ink composition of the present invention are within the following ranges.

[0101] Whitening agent: 10%-60% by weight Adhesive: 1%-60% by weight; Solvent: 20%-89% by weight; Moisturizer: 0%-25% by weight; Dispersant 0%-10% by weight; The percentage by weight is based on the weight of the edible ink composition.

[0102] (Method for preparing edible ink composition) Another subject of the present invention is a method for preparing edible ink compositions, particularly edible ink compositions for offset printing, the method comprising the steps of mixing a whitening agent (such as magnesium carbonate), a binder, a solvent, and any optional additional components as components of the edible ink composition, thereby providing an edible ink composition. The mixing of the components can be carried out in any order.

[0103] Depending on the properties of the whitening agent, especially in the case of white pigments, the method may include the step of dispersing the whitening agent in a solvent.

[0104] In one embodiment, a method for preparing an edible ink composition includes the following steps: (i) Dissolve the adhesive in a solvent. (ii) Add a whitening agent, particularly a white pigment, to the adhesive solution provided in step (i); and (iii) Disperse the whitening agent, especially the white pigment, in the binder solution.

[0105] (Printing method) Another subject of the present invention is a printing method comprising the step of offset printing an edible ink composition onto a printing substrate.

[0106] Offset printing is particularly suitable for printing on printing substrates such as solid food and solid pharmaceutical preparations using edible ink compositions containing white pigments according to the present invention.

[0107] For example, printing on capsules can be done directly using the edible ink composition of the present invention, or further diluted with a solvent as needed, for example, to adjust the final viscosity, and then printed using an offset printing press.

[0108] (Printing object) Another subject of the present invention is a printing substrate for offset printing using an edible ink composition.

[0109] The printing substrate can be a solid food or a solid pharmaceutical preparation, preferably a hard capsule, soft capsule, tablet or capsule.

[0110] In the case of hard capsules, the capsule matrix material can be any known material that can be used in pharmaceuticals and health foods, such as gelatin, pullulan, cellulose-based polymers such as hydroxypropyl methylcellulose (HPMC), cellulose acetate phthalate (CAP), hydroxypropyl methylcellulose acetate succinate (HPMCAS), hydroxypropyl methylcellulose phthalate (HPMCP), ethyl acrylate-methyl methacrylate copolymer, polyvinyl alcohol (PVA), starch-based materials, and combinations of these capsule matrix materials. HPMC capsules, gelatin capsules, and pullulan capsules are preferred.

[0111] The capsules can be sealed with a belt or a closed seal. The capsule shells can also be colored with known colorants, preferably natural dyes.

[0112] Solid foods such as sugars and candies can also be used as printing substrates for the edible ink compositions of the present invention.

[0113] Effects of the present invention By using the edible ink composition containing a whitening agent according to the present invention for offset printing on printing substrates such as tablets, capsules, and pouches, it is possible to obtain white and clear printed materials at high speed. Colored printed materials can also be obtained when dyes having colors other than white are added to the edible ink composition. These printed materials also exhibit good peel resistance and other properties.

[0114] Imprints formed on printing substrates using the above-described edible ink composition containing a whitening agent according to the present invention, and printing substrates such as capsules printed using the above-described edible ink composition containing a whitening agent according to the present invention, are stable over time and under light.

[0115] The printed capsules also meet the characteristics, quality, and features of capsules as defined in the Japanese Pharmacopoeia, namely, tests for appearance, properties, and purity, and can be used for pharmaceutical or food purposes in exactly the same manner as regular capsules.

[0116] Example The present invention will be described in detail based on the following embodiments. Undoubtedly, these embodiments do not limit the present invention.

[0117] Example 1 Ink film formation test Samples of edible ink compositions were prepared having the composition shown in Table 1 as a percentage by weight based on the weight of the edible ink composition.

[0118] Table 1 (Preparation of edible ink composition) HPC (Nisso Corporation: Cerny SSL) and PVP (BASF Corporation: PVP90) are used as binders in edible ink compositions.

[0119] Use the whitening agent described below: Basic magnesium carbonate (Kanto Chemical Industry Co. Ltd.) Heavy magnesium carbonate (Konoshima Chemical Co., Ltd.) Light magnesium carbonate (Konoshima Chemical Co., Ltd.) Magnesium sulfate (Kanto Chemical Industry Co. Ltd.) Magnesium hydroxide (Konoshima Chemical Co., Ltd.) Magnesium chloride (Kanto Chemical Industry Co. Ltd.) Magnesium phosphate (Budenheim). Magnesium stearate (Nitto Chemical Industry). Calcium carbonate (Kanto Chemical Industry Co. Ltd.) Calcium hydroxide (Kanto Chemical Industry Co. Ltd.) Tricalcium phosphate (Kanto Chemical Industry Co. Ltd.) Calcium hydrogen phosphate (Kyowa Chemical Industry) Calcined calcium (CaO, NC Corporation). Calcium citrate (Fuso Chemical Co., Ltd.) Calcium stearate (Nitto Chemical Industry Co.) Calcium pantothenate (DSM Japan KK). Calcium gluconate (Fuso Chemical Co., Ltd.) Potassium aluminum sulfate (Kosakai Chemical Industry Co. Ltd.) Anhydrous sodium sulfate (akasugi Pharmaceutical Co., Ltd.) Sodium alginate (Kimica Corporation) Sodium pyrophosphate (TAIHEI CHEMICAL INDUSTRIAL CO., LTD.) Clusterd dextrin (Glico Nutrition Co., Ltd.) Cyclodextrin (Nihon Shokuhin Kako Co., Ltd.), Pregelatinized starch (Asahi Kasei Chemicals Corporation). Xylitol (Xlear) Glucose (Nihon Shokuhin Kako Co., Ltd.), Gelatin powder (Rousselot Japan KK) Gum arabic (Sanei Yakuhin Boeki Co. LTD.) Brazilian carnauba wax (Freund Sangyo) Gel polysaccharide (Mitsubishi Corporation Life Sciences Limited). Inulin (Fuji Nihon Seito Corporation), L-Glutamic Acid (Ajinomoto Co.Ink.) DL-alanine (Ajinomoto Healthy Supply Co., Inc.) Anhydrous crystalline maltose (NAGASE & CO., LTD.). Kawai Material Refined bentonite (Hojun). Succinyl polysaccharide (DSP Gokyo). Guar gum (DSP Gokyo). Konjac potato extract (Shimizu Chemical). Agar (Ina Foods) Pectin (Sansho Co.,LTD.) Activated clay (Mizusawa Industrial Chemicals, Ltd.) Dissolve HPC and PVP completely in ethanol at room temperature to provide an ethanol solution for the binder. If the pigment particles are large, grind them into fine particles using a grinder or mortar and pestle, and add them to the ethanol solution of the binder prepared above, stirring thoroughly with a spoon until the dispersion is sufficiently homogeneous.

[0120] (Formation of ink film) Two 83 μm thick adhesive tapes are pasted parallel to each other onto a flat glass plate, with a gap between the two tapes. A small amount of the prepared ink composition is placed in the space between the two tapes, and a circular glass rod is slid across the gap between the two tapes to perform rod coating of the ink composition. The thickness of the tape strips acts as a spacer, resulting in a uniformly thick ink composition coating.

[0121] (result) When the ink composition, applied in film form, to a flat glass plate is placed in a room at 25°C and 45% RH, all inks dry within 10 minutes. Ink that dries within 10 minutes under these conditions can be determined to be acceptable as ink for offset printing.

[0122] The actual thickness of the dry ink obtained by offset printing is approximately 5 μm. When attempting to print this thickness in the laboratory, the ink dries before printing, making it difficult to assess the drying rate. However, experience has shown that under the aforementioned conditions—that is, if the ink is applied to a glass plate at a thickness of 83 μm and dried within 10 minutes at 25°C and 45% RH—printing with an offset printing press will not be problematic.

[0123] Example 2 Evaluation of ink whiteness White performance test method: Prepare ink compositions comprising each of the whitening agents described in Example 1 and HPC and PVP as binders: Add 3 g of whitening agent to 7 g of test base solution (binder ethanol solution, binder:ethanol weight ratio = 3.5:66.5), stir thoroughly with a spoon, and use as test solution (ink composition).

[0124] The test solution was applied to a glass plate in the same manner as in Example 1. After the coated ink composition dried at room temperature, the L value was measured using a Ci7600 colorimeter manufactured by X-Rite.

[0125] (result) The test results are shown in Table 2 below.

[0126] The higher the L value, the stronger the whiteness. Here, those with an L value of 70 or greater are considered acceptable (〇), and those with an L value less than 70 are considered unacceptable (×).

[0127] Table 2 Shellac is used as a binder for titanium dioxide inks.

[0128] Table 2 shows the L-values ​​and ratings of the various whitening agents tested. Among the whitening agents tested, those not listed in Table 2 (magnesium sulfate, magnesium chloride, dicalcium phosphate, calcium citrate, calcium pantothenate, calcium gluconate, potassium aluminum sulfate, anhydrous sodium sulfate, sodium alginate, sodium pyrophosphate, tetradextrin, cyclodextrin, pregelatinized starch, xylitol, glucose, gelatin powder, gum arabic, gelling polysaccharide, inulin, L-glutamic acid, DL-alanine, anhydrous crystalline maltose, succinosaccharide, guar gum, konjac potato extract, and pectin) were all rated ×. As a comparison product, a commercially available white ink containing titanium dioxide was used; the comparison product was White manufactured by San-Ei GenFFI Co., Ltd. Magnesium carbonate exhibited high whiteness regardless of whether the binder was HPC or PVP.

[0129] (Example 3) Preparation of edible ink compositions containing magnesium carbonate An edible ink composition having the composition shown in Table 3 was prepared by the same method as described in Example 1.

[0130] Table 3 [Weight %] The edible ink composition was prepared in the same manner as described in Example 1. Any additional components were added to the solution of binder and ethanol before the whitening agent was added.

[0131] Each ink composition was applied to a glass plate in the same manner as in Example 1, and then placed in a room at 25°C and 45% RH. All ink compositions dried within 10 minutes.

[0132] Ink composition 3-1 has a uniform gray color because it contains squid ink pigment. Ink compositions 3-2 and 3-3 exhibit a uniform white color. Magnesium oxide is added to 3-1 as part of the white pigment. Magnesium oxide can be used as a white pigment in edible inks.

[0133] Industrial applicability The edible ink composition of the present invention, being titanium dioxide-free, enables high-value-added printing that is both healthy and safe, and is socially desirable. Furthermore, the whitening agents used in the present invention, such as magnesium carbonate, magnesium hydroxide, magnesium stearate, calcium hydroxide, calcined calcium, calcium stearate, carnauba wax, tricalcium phosphate, dolomite, bentonite, agar, and activated white clay, are edible and possess good whiteness and opacity, thus allowing for clear printing of white and other colors. Moreover, the edible ink composition of the present invention, due to the use of alcohol-soluble binders and alcohol as a solvent, dries quickly and can be used as an ink for offset printing.

[0134] The edible ink composition of the present invention can be used as an ink composition for offset printing on the surface of solid foods, solid pharmaceutical preparations, especially capsules, tablets and sachets, particularly capsules.

Claims

1. An edible ink composition for offset printing, comprising a whitening agent, an alcohol-soluble binder, and a solvent, wherein the edible ink composition is free of titanium dioxide. The whitening agent mentioned herein is selected from the group consisting of: magnesium carbonate, magnesium hydroxide, magnesium stearate, calcium hydroxide, calcined calcium, calcium stearate, carnauba wax, tricalcium phosphate, dolomite, bentonite, agar, activated clay, and mixtures thereof; The alcohol-soluble binder is hydroxypropyl cellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, polyvinylpyrrolidone, or a mixture thereof, and The solvent is an alcohol.

2. The edible ink composition according to claim 1, wherein the whitening agent is a white pigment and is magnesium carbonate.

3. The edible ink composition according to claim 1 or 2, wherein after drying the edible ink composition, the amount of whitening agent in the dried ink is 30% to 90% by weight, preferably 50% to 80% by weight, based on the weight of the dried ink.

4. The edible ink composition according to any one of claims 1 to 3, wherein the solid content of the edible ink composition is from 10% to 90% by weight, preferably from 20% to 50% by weight, based on the weight of the edible ink composition.

5. The edible ink composition according to any one of claims 1 to 4, wherein the solvent evaporates or evaporates by drying the edible ink composition and leaves substantially no residue in the dried edible ink composition.

6. The edible ink composition according to any one of claims 1 to 5, wherein the solvent is selected from the group consisting of ethanol, propanol, isopropanol and butanol, preferably ethanol or butanol, and even more preferably ethanol.

7. The edible ink composition according to any one of claims 1 to 5, comprising as an additional component a colorant having a color other than white.

8. The edible ink composition according to any one of claims 1 to 7, comprising as an additional component an additive selected from the group consisting of: sorbitol, glycerol, propylene glycol, sucrose, glucose, galactose, fructose, xylitol, maltose, maltitol, trehalose, lactose, alcohol-soluble oligosaccharides, cationic or anionic surfactants, glycerol fatty acid esters, polysaccharides, nonionic surfactants such as glycerol fatty acid esters, dehydrated sorbitol fatty acid esters and sucrose fatty acid esters, polycarboxylic acid polymer dispersants, phosphates such as polyphosphates and hexametaphosphates, and clay minerals having a zeta potential such as kaolin, halloysite, montmorillonite, diaspore and silica anhydride, and combinations thereof.

9. A printing substrate for offset printing using an edible ink composition according to any one of claims 1 to 8; preferably, the printing substrate is a solid food or a solid pharmaceutical preparation; the solid pharmaceutical preparation is preferably a hard capsule, soft capsule, tablet, or capsule capsule.

10. A method for preparing an edible ink composition according to any one of claims 1 to 8, comprising the following steps: The edible ink composition is provided by mixing a whitening agent, a binder, a solvent, and any optional additional components that are components of the edible ink composition.

11. A method for printing, the method comprising the step of offset printing an edible ink composition according to any one of claims 1 to 8 onto a printing substrate.

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