Ink, printed material with printed layer formed by printing ink, and production method for printed material obtained by printing ink

Abstract

To provide an ink comprising a natural dye.SOLUTION: The present invention provides an ink that contains at least a colorant and a solvent, where the colorant contains phycocyanin, as well as a printed material with a printed layer formed by printing the ink, and a production method for a printed material obtained by printing the ink.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an ink, a printed item having a printed layer formed by printing the ink, and a method for producing a printed item obtained by printing the ink. [Background technology]

[0002] Traditionally, coloring materials such as dyes and pigments have been widely used to impart color to inks, paints, cosmetics, and other applications. Among these, synthetic colorants such as Blue No. 1 and Yellow No. 5 have also been used in food applications. In recent years, there has been a strong tendency to avoid synthetic colorants due to concerns about their carcinogenicity, and expectations are growing for natural dyes, which are thought to be safer. Recently, there is an increasing demand for natural materials not only for food applications as described above but also for industrial applications, and there is a demand for the use of natural dyes as colorants for packaging and cushioning materials. When packaging paper or cushioning materials colored with industrial dyes are used as food containers, problems have arisen such as the color bleeding or fading of the dye components due to water such as rainwater, which can contaminate food that has come into contact with the paper or cushioning materials.

[0003] For example, phycocyanin, an algae pigment, is a natural blue pigment. Phycocyanin is a protein-bound pigment that is known to be able to be extracted from cyanobacteria such as spirulina. Phycocyanin is a pigment that exhibits a vivid blue color, and there are high expectations in the market for it as a sustainable pigment.

[0004] Patent Document 1 describes an acidic aqueous coloring material solution that contains phycocyanin (A), a polycarboxylic acid (B) containing one or more hydroxyl groups, and at least one nonionic emulsifier (C) having an HLB of 15 or more selected from the group consisting of sucrose esters and polyglycerol esters, and discloses that the aqueous coloring material solution is used in foods and beverages, pharmaceuticals such as tablets, and cosmetics.

[0005] However, research into the blending of phycocyanin with industrial pigments has not been carried out sufficiently, and there has been a problem in that its usefulness has not been fully elucidated or utilized. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 129745 [Patent Document 2] Japanese Patent Application Publication No. 11 299450 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, the problem to be solved by the present invention is to provide an ink using phycocyanin, a printed matter having a printing layer formed by printing the ink, and a method for producing a printed matter obtained by printing the ink. [Means for solving the problem]

[0008] The ink contains at least a colorant and a solvent, and the colorant contains phycocyanin.

[0009] The phycocyanin in the ink is derived from blue-green algae of the genus Spirulina.

[0010] The ink contains phycocyanin Linablue G1 (trade name, manufactured by DIC Lifetech Co., Ltd.).

[0011] The ink contains phycocyanin as a colorant that has been insoluble in water (laked).

[0012] The ink contains a colorant that is a composite of phycocyanin and a silica structure.

[0013] The ink is a two-phase continuous silica structure having a silica phase as a main component, the silica phase being chemically bonded via Q4 bonds, and an air phase.

[0014] The ink further contains a dispersion resin.

[0015] The ink further contains a binder.

[0016] The ink contains a resin in which the binder is produced using a compound derived from a biomass resource.

[0017] In the ink, the compound derived from a biomass resource is a diol compound.

[0018] The ink contains an organic solvent as a solvent.

[0019] The ink contains water or an aqueous medium as a solvent.

[0020] The ink further contains a pH adjuster.

[0021] The inks may be inkjet, flexographic, or gravure.

[0022] The ink is intended for printing on a paper substrate.

[0023] The ink is intended for printing on plastic substrates.

[0024] The ink is for deinking.

[0025] The ink may be for food, cosmetic, industrial or pharmaceutical use.

[0026] The printed matter has a print layer formed by printing ink.

[0027] The printed matter can be obtained by printing ink onto a paper substrate or a plastic substrate by inkjet printing, flexographic printing, or gravure printing. Effect of the Invention

[0028] According to the present invention, there is provided an ink using phycocyanin, a printed matter having a printing layer formed by printing the ink, and a method for producing a printed matter obtained by printing the ink, which has a particularly remarkable technical effect. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The present invention will be described in detail below.

[0030] The present invention is an ink comprising at least a colorant and a solvent, the colorant comprising phycocyanin.

[0031] Phycocyanin used in the present invention is a protein-bound pigment that has phycocyanobilin as a chromophore. Phycocyanin has a structure in which phycocyanobilin and protein are bound together.

[0032] Examples of phycocyanin according to the present invention include phycocyanins derived from algae, such as phycocyanin derived from blue-green algae, phycocyanin derived from red algae, and phycocyanin derived from cryptophyte. Among these, phycocyanin derived from blue-green algae is preferred because it can be harvested in large quantities.

[0033] Examples of cyanobacteria include those of the genus Spirulina, Arthrospira, Aphanizomenon, Fisherella, Anabaena, Nostoc, Synechocystis, Synechococcus, Tolypothrix, Aphanothece, Mastigoclaus, Pleurocapsa, etc. Among them, cyanobacteria of the genus Spirulina and Arthrospira, which are produced on an industrial scale and have been confirmed to be safe, are preferred, and those of the genus Spirulina are more preferred.

[0034] The raw material for phycocyanin is not particularly limited, but can be one obtained from biological materials such as algae containing phycocyanin, such as spirulina, blue-green algae, red algae, and cryptophyte, and preferably phycocyanin obtained from blue-green algae, and more preferably phycocyanin obtained from spirulina.

[0035] Spirulina used as a raw material for phycocyanin is a unicellular algae belonging to the order Oscillatory, Cyanobacteria, and examples thereof include Spirulina geitlerii, Spirulina platensis, Spirulina maxima, Spirulina mayer, Spirulina laxissima, Spirulina aldaria, etc. The origin of the spirulina in the present invention is not particularly limited, and natural products and artificially cultured products can be used as appropriate.

[0036] The phycocyanin used in the present invention can be obtained by extracting the above-mentioned spirulina, blue-green algae, red algae, cryptophyte algae, etc. The method for extracting phycocyanin is not particularly limited as long as it is a method that can obtain phycocyanin, and known methods such as crushing, extraction, squeezing, centrifugation, and supercritical extraction can be used alone or in combination. In addition, known extraction methods such as the methods described in JP-A-2003-342489 and JP-A-4677250 can be used.

[0037] The extraction solvent used to extract phycocyanin may be one or a combination of two or more selected from water or organic solvents, and these extraction solvents may be, for example, water, organic solvents such as alcohols such as ethanol and methanol, and preferably water, ethanol, and mixtures thereof. In addition, when extracting with these extraction solvents, various additives may be added to the extent that the effects of the present invention are not impaired in order to increase the extraction efficiency.

[0038] The amount of the extraction solvent used to extract phycocyanin is preferably about 1 to 1000 times, more preferably about 5 to 200 times, the amount of the raw algae such as spirulina. The extraction method is not particularly limited, but the extraction temperature is usually within the range of 10 to 50 degrees under normal pressure, and the extraction operation may be performed once or multiple times. When extracting phycocyanin multiple times, fresh extraction solvent can be added to the residue after extraction again and the extraction operation can be performed, or the extraction solvent can be brought into contact with the extraction raw material multiple times. If necessary, further purification treatment such as centrifugation or filtration can be added, and the mixture can be concentrated and dried by a vacuum concentration device such as an evaporator or by removing the solvent by heating.

[0039] The phycocyanin used in the examples of the present invention is a commercially available product mixed with a stabilizer, Linablue G1 (manufactured by DIC Lifetech Co., Ltd., trehalose 55%, spirulina pigment 40%, trisodium citrate 5%). As described in JP-A-11-299450, trehalose is used to increase thermal stability, and citric acid is used as a pH adjuster.

[0040] The colorant may contain phycocyanin insoluble in water (laked).

[0041] The colorant may be a composite of phycocyanin and a silica structure.

[0042] The silica structure may be a two-phase continuous silica structure consisting of a phase mainly composed of silica in which the chemical bonds are Q4 bonds, and an air phase.

[0043] The fact that the chemical bond of silica is composed of Q4 bonds means that it does not substantially have silanol groups. The silanol group is a functional group that is hydrophilic and has a high affinity for water. For this reason, for example, when a water-soluble dye is used in combination with a silica compound having a silanol group, the silica compound adsorbs or absorbs water, which makes the dye more likely to come off the silica, and as a result, it is thought that this may cause bleeding. On the other hand, it is difficult for silica composed of highly hydrophobic Q4 bonds to adsorb water-soluble dyes to its surface. In this situation, the specific structure of phycocyanin can interact with the two-phase cocontinuous silica structure of the present application, and as a result, a complex of phycocyanin and a two-phase cocontinuous silica structure can be prepared in a simple manner, and this can be used as a water-insoluble dye. This is the present invention.

[0044] The two-phase co-continuous silica structure is not particularly limited as long as it is substantially free of silanol groups as described above and the air phase and the silica phase are co-continuous.

[0045] A simple method for obtaining such a two-phase bicontinuous silica structure is to use silica obtained by an existing silica synthesis method as a precursor raw material, utilize the affinity between a metal oxide that exhibits high-temperature sublimation and silica, and infiltrate the vapor of the metal oxide near the silanol groups, where the silica is scraped off, the chemical bonds of the silica are converted into Q4 bonds, and hollow tunnels are formed from the outer surface of the structure to the entire interior, making the two phases of silica and air continuous with each other.

[0046] The ink of the present invention may further contain a dispersing resin. The dispersing resin is adsorbed around the colorant, thereby imparting dispersion stability to the colorant in the solvent. Examples of the dispersing resin include polyvinyl alcohols, polyvinylpyrrolidones, acrylic resins such as acrylic acid-acrylic acid ester copolymers, polyurethane resins, acrylic acid-polyurethane copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, styrene-acrylic resins such as styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymers, styrene-maleic acid copolymers (including resins made from half-esterified or esterified maleic acid), styrene-maleic anhydride copolymers, vinylnaphthalene-acrylic acid copolymers, and salts of the aqueous resins. The carboxyl groups of these resins function not only as hydrophilic groups but also as crosslinkable functional groups, so that the crosslinking treatment described below can be expected to improve gloss and abrasion resistance. The dispersion resin may be, for example, a resin having an anionic group, such as a carboxyl group, a sulfonic acid group, or a phosphoric acid group.

[0047] The ink of the present invention may further contain a binder. The binder resin generally refers to a resin having appropriate pigment affinity and dispersibility and rheological properties required for printing ink. For example, non-reactive resins include diallyl phthalate resin, epoxy resin, epoxy ester resin, polyurethane resin, polyester resin, petroleum resin, rosin ester resin, poly(meth)acrylic acid ester, cellulose derivative, vinyl chloride-vinyl acetate copolymer, polyamide resin, polyvinyl acetal resin, butadiene-acrylonitrile copolymer, etc. In addition, reactive resins having at least one polymerizable group in the molecule include epoxy acrylate compounds, urethane acrylate compounds, polyester acrylate compounds, etc. The binder resin may be used alone or in combination of two or more types.

[0048] The binder may contain a resin produced using a compound derived from a biomass resource. Examples of the compounds derived from biomass resources include diol compounds, propylene, ethylene, monoethylene glycol, terephthalic acid, sebacic acid, hexamethylenediamine, isosorbide, hydroxyalkanoic acid, lactic acid, amino acids such as aspartic acid, succinimide, etc. Resins can be obtained by chemically synthesizing, fermenting, etc., these compounds.

[0049] In the ink of the present invention, the solvent may contain an organic solvent, which is not particularly limited and may include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, hexylene glycol, 1,3-butylene glycol, thiodiethylene glycol, glycerin, 2-pyrrolidone, N-methyl-2-pyrrolidone, etc.

[0050] The solvent may contain water or an aqueous medium. In the case of an aqueous ink, water is used as the main solvent, but from the viewpoint of preventing nozzle clogging, it is preferable to use water from which hard water components (polyvalent metal salts) in the water have been removed. In addition, if necessary, a low-boiling organic solvent such as methyl ethyl ketone, methanol, or ethanol, or an acetate ester may be mixed and used.

[0051] The ink of the present invention may further contain a pH adjuster. As the pH adjuster, inorganic or organic alkali or inorganic or organic acid can be used, and specifically, potassium hydroxide, sodium carbonate, diethanolamine can be used as the alkali, and phosphoric acid, ammonium sulfate, glycolic acid, etc. can be used as the acid. In the case of oil-based ink, acetic acid, organic amines, etc. can be used preferably.

[0052] The inks of the present invention may be suitable for inkjet printing, flexographic printing, or gravure printing.

[0053] When the phycocyanin composition is used as a colorant for ink, the same method of use as that of colorants or fillers conventionally used for these purposes can be applied. In this case, the phycocyanin composition of the present invention, particularly the water-insoluble pigment in the form of a complex, may be dispersed only in a thermoplastic resin, but it can also be dispersed in a printing ink vehicle containing a thermoplastic resin as an essential component.

[0054] When used as an inkjet printing ink, the resin to be combined may be a conventionally known water-soluble resin or oil-soluble resin. As the water-soluble resin, polyvinyl alcohol resin, polyester resin, water-soluble silicone-modified alkyd resin, water-soluble modified epoxy resin, water-soluble nylon resin, water-soluble melamine resin, etc. are preferably used. As the oil-soluble resin, polyester resin, acrylic resin, methacrylic resin, etc. are preferably used.

[0055] Vehicles for gravure printing inks and flexographic printing inks are produced from raw materials such as 10 to 50% (by mass) of one or more resins selected from rosins, maleic acid resins, polyamide resins, vinyl resins, cyclized rubbers, chlorinated rubbers, ethylene-vinyl acetate copolymer resins, urethane resins, polyester resins, alkyd resins, nitrocellulose, cellulose acetate, etc., and 30 to 80% (by mass) of a solvent such as alcohols, toluene, n-hexane, ethyl acetate, cellosolve, butyl cellosolve acetate, etc.

[0056] The inks of the present invention may be intended for printing on a paper substrate.

[0057] The ink of the present invention may be used for printing on a plastic substrate. When used for printing on a plastic substrate, a thermoplastic resin (plastic) for thermoforming such as injection molding or press molding, such as polyolefins such as polyethylene and polypropylene, or polyvinyl chloride resin, is used, and the ink of the present invention can be used by kneading it into these resins by a conventionally known method.

[0058] The inks of the present invention may be used for deinking.

[0059] The inks of the present invention may be for food, cosmetic, industrial or pharmaceutical use.

[0060] The present invention may also be a printed matter having a printed layer formed by printing the above ink.

[0061] The present invention may also be a method for producing a printed matter obtained by printing the ink on a paper substrate or a plastic substrate by inkjet printing, flexographic printing, or gravure printing.

[0062] The present invention will be described in more detail below with reference to formulation examples, but the present invention is not limited to these formulation examples.

[0063] Ink formulation example 1 Linablue G1 (DIC Lifetech Co., Ltd., trehalose 55%, spirulina pigment 40%, trisodium citrate 5%) 0.5 to 20% by mass Acrylic dispersion resin 0.1 to 10 parts by mass Poly(meth)acrylic ester binder resin 0.1 to 10% by mass Preservatives: 0-5% by mass Surface tension adjuster 0~5% by mass Aqueous solvent balance

[0064] Ink formulation example 2 Linablue G1 (DIC Lifetech Co., Ltd., trehalose 55%, spirulina pigment 40%, trisodium citrate 5%) 0.5 to 20% by mass Polyurethane resin dispersion resin 0.1 to 10 parts by mass Polyurethane resin binder resin 0.1 to 10 mass% Preservatives: 0-5% by mass Surface tension adjuster 0~5% by mass Aqueous solvent balance

[0065] Ink formulation example 3 Linablue G1 (DIC Lifetech Co., Ltd., trehalose 55%, spirulina pigment 40%, trisodium citrate 5%) 0.5 to 20% by mass Styrene-acrylic resin dispersion resin 0.1 to 10 parts by mass Polyester acrylate compound binder resin 0.1 to 10% by mass Preservatives: 0-5% by mass Surface tension adjuster 0~5% by mass Aqueous solvent balance

[0066] In addition, in the above formulation example, Linablue G1 can be changed to a phycocyanin powder in which phycocyanin and a silica structure are composited. Phycocyanin powder composited with silica structure was obtained by, for example, adding the raw materials of Production Examples A1 to A3 described later and a stirrer to a 100 mL eggplant flask, stirring the solution for 10 minutes at room temperature (20°C) and leaving it for 24 hours under light-shielded conditions. The mixture was filtered through filter paper, washed with 200 mL of ion-exchanged water until the washing liquid was no longer colored, and the solid after filtration was dried in a vacuum dryer (740 mmHg) at 20°C for 12 hours to obtain a powder.

[0067] Manufacturing example A1 Silica structure 500mg Linablue G1 (DIC Lifetech Co., Ltd., trehalose 55%, spirulina pigment 40%, trisodium citrate 5%) 1250mg Ion-exchanged water 5mL

[0068] Manufacturing example A2 Silica structure 500mg Linablue G1 (DIC Lifetech Co., Ltd., trehalose 55%, spirulina pigment 40%, trisodium citrate 5%) 1250mg Ethylene glycol solution 5mL

[0069] Manufacturing example A3 Silica structure 500mg Brilliant Blue FCF (blue dye, manufactured by Kanto Chemical Co., Ltd.) 500mg Ion-exchanged water 5mL

Claims

1. Contains at least a colorant and a solvent, The ink characterized in that the colorant contains phycocyanin.

2. 2. The ink according to claim 1, wherein the phycocyanin is derived from blue-green algae of the genus Spirulina.

3. 3. The ink according to claim 1, wherein the phycocyanin is Linablue G1 (trade name, manufactured by DIC Lifetech Co., Ltd.).

4. The ink according to any one of claims 1 to 3, wherein the colorant contains phycocyanin that has been insolubilized (laked) in water.

5. The ink according to any one of claims 1 to 3, wherein the colorant is a composite of phycocyanin and a silica structure.

6. 6. The ink according to claim 5, wherein the silica structure is a two-phase continuous silica structure comprising a phase mainly composed of silica whose chemical bonds are Q4 bonds, and an air phase.

7. The ink according to any one of claims 1 to 6, further comprising a dispersing resin.

8. The ink according to any one of claims 1 to 7, further comprising a binder.

9. The ink of claim 8 , wherein the binder comprises a resin produced using compounds derived from biomass resources.

10. The ink according to claim 9 , wherein the compound derived from a biomass resource is a diol compound.

11. The ink according to any one of claims 1 to 10, wherein the solvent comprises an organic solvent.

12. The ink according to any one of claims 1 to 11, wherein the solvent comprises water or an aqueous medium.

13. The ink according to any one of claims 1 to 12, further comprising a pH adjuster.

14. An ink according to any one of claims 1 to 13, which is for inkjet printing, flexographic printing or gravure printing.

15. An ink according to any one of the preceding claims for printing on a paper substrate.

16. The ink according to any one of claims 1 to 14, which is for printing on a plastic substrate.

17. The ink according to any one of claims 1 to 16, which is for deinking.

18. The ink according to any one of claims 1 to 17, which is for food, cosmetic, industrial or pharmaceutical use.

19. A printed matter having a printed layer formed by printing the ink according to any one of claims 1 to 18.

20. A method for producing a printed matter by printing the ink according to any one of claims 1 to 19 onto a paper substrate or a plastic substrate by inkjet printing, flexographic printing, or gravure printing.