Natural pigment-containing toner

Abstract

To provide a natural pigment-containing toner which uses phycocyanin, known to be susceptible to problems such as elution to water and associated color fading, as a pigment and is capable of maintaining its color tone for a prolonged period of time.SOLUTION: A color toner is provided containing a colorant (A), binder resin (B), magnetic powder (C), and anti-fading agent (D), where the colorant (A) is a water-insoluble pigment composition containing phycocyanin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a natural pigment-containing toner that contains phycocyanin. [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.

[0003] In recent years, there has been a strong tendency to avoid synthetic colorants due to concerns about their carcinogenicity, etc., and expectations are growing for natural dyes, which are thought to be safer. However, it is often difficult for natural dyes to maintain their vivid colors under various environments.

[0004] For example, phycocyanin, an algae pigment, is a natural blue pigment. Phycocyanin is a protein-bound pigment that is known 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. However, phycocyanin is water-soluble, and it has been revealed that when used in cosmetics or food coloring, it is prone to problems such as dissolution into water and the associated discoloration.

[0005] There are various methods for making water-soluble dyes water-insoluble. For example, an aqueous solution of alkali silicate is spray-dried, and the particles obtained by spraying are immersed in an aqueous solution containing a sufficient amount of acid to remove the alkali in the particles, thereby removing the alkali and converting the particles into silica, thereby obtaining spherical silica particles with a solid or hollow interior. However, it has been proposed that if a dye is dispersed in the aqueous solution of alkali silicate and used, it is possible to obtain dye-containing silica-based particles colored in the same color tone as the dye used (see, for example, Patent Document 1). However, the above-mentioned phycocyanin cannot be encapsulated in silica particles by such a method because it cannot maintain its color tone stably against changes in pH, such as alkalinity and acidity.

[0006] Also, a method has been provided in which reactive functional groups are added to the surface of fine particles such as colloidal silica, fluorescent dyes are immobilized via the reactive functional groups, and the surface is further covered with a silica coating to obtain silica particles with immobilized dyes (see, for example, Patent Document 2). In this method, the chemical structure of the immobilized dye is partially changed to form new bonds, so there is a concern that the color tone will not be maintained. In addition, this method also uses alkaline or acidic compounds in combination, so there is a concern about the color tone stability of phycocyanin.

[0007] Furthermore, all of the techniques for producing these colored particulate materials require complicated processes, which results in an increased production cost.

[0008] Although several inks using natural pigments as raw materials have been disclosed, they do not specify a specific colorant (see, for example, Patent Document 3), or are characterized by utilizing the fading properties of the natural pigments to fade after a certain period of time (see, for example, Patent Document 4), and do not take into consideration maintaining the vivid color of the pigments over the long term. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2013-095797 A [Patent Document 2] JP 2008-247713 A [Patent Document 3] Japanese Patent Application Publication No. 08-109346 [Patent Document 4] JP 2013-082922 A Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a natural colorant-containing toner that uses phycocyanin as a colorant and is capable of retaining its color tone for a long period of time. [Means for solving the problem]

[0011] As a result of intensive research to solve the above problems, the present inventors have found that the above problems can be solved by making phycocyanin water-insoluble and adding various anti-fading agents, and have completed the present invention.

[0012] That is, the present invention includes the following aspects. [1]

[0013] A toner containing a natural pigment, the toner comprising a colorant (A), a binder resin (B), a magnetic powder (C) and a discoloration inhibitor (D), 1. A toner containing a natural pigment, wherein the colorant (A) is a water-insoluble pigment composition containing phycocyanin. [2]

[0014] 2. The natural dye-containing toner according to claim 1, wherein the colorant (A) is a water-insoluble dye composition in which a metal hydroxide or oxide is coated with phycocyanin. [3]

[0015] The composition of the metal hydroxide or oxide and phycocyanin is in the mass ratio: 3. The toner according to claim 2, wherein the ratio of metal hydroxide or oxide:phycocyanin is 99.9:0.1 to 10:90. [4]

[0016] 2. The toner according to claim 1, wherein the amount of the colorant (A) blended is 0.5 to 25 parts by mass based on 100 parts by mass of the binder resin (B). [5]

[0017] 4. The water-insoluble pigment composition according to claim 1, wherein the phycocyanin is derived from cyanobacteria of the genus Spirulina. [6]

[0018] 4. The water-insoluble dye composition according to claim 1, wherein the phycocyanin is Linablue G1 (trade name, manufactured by DIC Lifetech Co., Ltd.). [7]

[0019] 2. The natural colorant-containing toner according to claim 1, wherein the anti-fading agent (D) is at least one selected from the group consisting of heat-resistant anti-aging agents, metal oxides and / or metal soaps. Effect of the Invention

[0020] According to the present invention, it is possible to provide a natural pigment-containing toner that uses phycocyanin as a pigment and is capable of retaining its color tone for a long period of time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The natural colorant-containing toner of the present invention will be described in detail below. However, the following description of the constituent elements is merely an example of one embodiment of the present invention, and the present invention is not limited to these contents.

[0022] (Colorant (A)) The coloring agent used in the present invention contains phycocyanin. The phycocyanin used in the present invention is a protein-bound pigment and has phycocyanobilin as a chromophore. Phycocyanin has a structure in which phycocyanobilin and protein are bound together.

[0023] 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.

[0024] 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.

[0025] In addition, as a raw material for preparing phycocyanin, raw cyanobacteria may be used, or dried cyanobacteria may be used. As for the dried product of cyanobacteria, raw cyanobacteria may be dried according to a conventional method, or a commercially available dried product may be used.

[0026] Phycocyanin can be obtained, for example, by suspending blue-green algae in water or a buffer solution such as a phosphate buffer or a citrate buffer, and extracting the phycocyanin from the blue-green algae.

[0027] The method for extracting phycocyanin is not particularly limited, and any commonly known method can be used.

[0028] A preferred embodiment of the extraction method is, for example, the extraction method described in JP 2006 230272 A. Specifically, the extraction method described in the following extraction method (i) can be mentioned. By the extraction method (i), phycocyanin with high purity and vivid color can be obtained.

[0029] <Extraction method (i)> The extraction method (i) is A first step of extracting phycocyanin from cyanobacteria into a water suspension; a second step of reacting a calcium salt with a phosphate in the extract to produce calcium phosphate and adsorbing impurities of phycocyanin to the calcium phosphate to obtain an adsorbate; and a third step of removing residual blue-green algae and adsorbed substances from the extract.

[0030] Furthermore, it is more preferable that the above extraction method (i) is the following extraction method (ii). <Extraction method (ii)> The extraction method (ii) is A first step of extracting phycocyanin from cyanobacteria into a water suspension; a second step of reacting a calcium salt with a phosphate in the extract to produce calcium phosphate and adsorbing impurities of phycocyanin to the calcium phosphate to obtain an adsorbate; The method includes a third step of removing residues of blue-green algae and adsorbed substances from the extract, and a step prior to the third step of adding a chelating agent to the extract.

[0031] The phycocyanin used in this invention was selected from the commercially available Linablue G1 (DIC Lifetech Co., Ltd., trehalose 55%, phycocyanin pigment 40%, trisodium citrate 5%) mixed with a stabilizer. As described in JP-A-11-299450, trehalose is used to increase thermal stability, and citric acid is used as a pH adjuster.

[0032] (Water-insoluble pigment composition) In an embodiment of the present invention, the water-insoluble pigment composition may consist of only phycocyanin, or may contain components other than phycocyanin as long as the effects of the present invention are obtained. Among them, the components other than phycocyanin are preferably metals or metal compounds, more preferably metal hydroxides or oxides, and even more preferably metal hydroxides or oxides coated with phycocyanin.

[0033] The metal elements in the metal or metal compound used in the present invention include those belonging to Groups 1 to 15 of the Periodic Table of Elements, excluding those in the first and second periods. Among them, metal elements such as iron, cobalt, nickel, zinc, aluminum, and titanium can be used, and one or more metal elements selected from them can be used. In the embodiment of the present invention, aluminum, titanium, and zinc are particularly preferred.

[0034] When the water-insoluble dye composition used in the present invention contains a metal or a metal compound and phycocyanin, in order to strengthen the physical adsorption of phycocyanin with the metal or metal compound, a metal hydroxide or oxide is preferably used as the metal or metal compound, and aluminum hydroxide, titanium oxide, and zinc oxide are particularly preferably used. It is preferable to add an alkali to a chloride such as aluminum chloride, titanium tetrachloride, or zinc chloride to form a slurry of aluminum hydroxide, titanium oxide, zinc hydroxide, etc., since this will strengthen the physical adsorption with phycocyanin. Furthermore, in order to strengthen the physical adsorption, it is more preferable that the surface of the metal or metal compound is coated with phycocyanin. The definition of coating refers to a state in which phycocyanin is present partially or uniformly on the metal surface and covers it.

[0035] The particle size of the metal or metal compound particles varies depending on the application, and the hue also varies depending on the particle size of the metal or metal compound particles. For example, 50 nm to 20 μm is preferable for food and cosmetic applications, and 50 to 500 nm is preferable for other applications.

[0036] When the water-insoluble pigment composition used in the present invention contains a metal or metal compound and phycocyanin, the mass ratio of the composition of the metal or metal compound and phycocyanin can be designed arbitrarily. In particular, when a metal hydroxide or oxide is used as the metal or metal compound, the ratio of the metal hydroxide or oxide:phycocyanin can be set to 99.9:0.1 to 10:90. Preferably, the ratio of the metal hydroxide or oxide:phycocyanin is 99:1 to 30:70.

[0037] (Method of producing water-insoluble dye composition) As a method for producing the water-insoluble dye composition of the present invention, when the water-insoluble dye composition contains a metal or metal compound and phycocyanin, a method of mixing particles of the metal or metal compound with phycocyanin in a solvent is preferable because it is possible to produce the most uniform water-insoluble dye composition.

[0038] The method for producing a water-insoluble pigment composition by mixing each substance in a solvent includes: 1) first preparing a dispersion of a metal or metal compound; 2) dissolving phycocyanin or a preparation containing phycocyanin in water to prepare an aqueous solution; 3) mixing the two liquids to prepare a water-insoluble pigment composition; and 4) filtering and drying the resulting mixed liquid containing the water-insoluble pigment composition. The mixing temperature may be room temperature or may be heated and mixed. Considering the decomposition temperature of phycocyanin alone, mixing is preferably performed at 10 to 60°C, more preferably 20 to 50°C.

[0039] As a method for mixing metal or metal compound with phycocyanin, a phycocyanin-containing aqueous solution may be mixed with an aqueous dispersion of a metal or metal compound, or vice versa, an aqueous dispersion of a metal or metal compound may be mixed with an aqueous solution containing phycocyanin, or these two liquids may be mixed little by little. Also, a powder of phycocyanin or a metal or metal compound may be added to a liquid of a metal or metal compound or phycocyanin, or a powder of a metal or metal compound and phycocyanin may be mixed and water may be added. The temperature for mixing may be room temperature or may be heated and mixed. In consideration of the decomposition temperature of phycocyanin alone, mixing is preferably performed at 10 to 60 ° C, more preferably 20 to 50 ° C. In addition, the pH range when mixing a metal or metal compound with a phycocyanin-containing aqueous solution is preferably 3.0 to 8.0, and more preferably adjusted to 4.0 to 7.5.

[0040] Examples of pH adjusters for adjusting the pH include hydrochloric acid, citric acid, acetic acid, lactic acid, etc. The pH range of the mixed solution when the pH adjuster is added is preferably 3.0 to 5.0, more preferably 3.5 to 5.0, from the viewpoint of efficiently adsorbing and insolubilizing the metal or metal compound and phycocyanin in the mixed solution.

[0041] The obtained mixture is filtered and dried to obtain a water-insoluble pigment composition. When the mixture is filtered through a filter such as a Nutsche filter, it is confirmed that the filtrate is not colored, and it is confirmed that the pigment phycocyanin is adsorbed to the metal or metal compound. In addition, the wet cake of the water-insoluble pigment composition is further repeatedly washed with water, and the filtrate is similarly colorless and transparent, and it is confirmed that the pigment component has not flowed out. The water-containing wet cake of the obtained water-insoluble pigment composition is dried at room temperature, by heating, vacuum, reduced pressure drying, etc., to obtain a dry water-insoluble pigment composition. The drying method and dryer can be any ordinary method and device, and are not limited.

[0042] The amount of the water-insoluble dye composition used in the natural dye-containing toner is not particularly limited, but is preferably 0.5 to 25 parts by mass per 100 parts by mass of the binder resin (B), and more preferably 4 to 10 parts by mass per 100 parts by mass of the binder resin in order to further enhance the charging performance of the colorant itself.

[0043] (Binder resin (B)) As the binder resin used in the natural colorant-containing toner of the present invention, any known and commonly used resins can be used. Among them, natural resins, synthetic resins, natural rubber, synthetic rubber, synthetic wax, etc. that exhibit adhesive properties under application of heat or pressure can be used.

[0044] Examples of natural resins useful in the present invention include balsam resin, rosin, shellac, and corval. These resins may be modified with one or more resins selected from vinyl resins, acrylic resins, alkyd resins, phenolic resins, and the like, which will be described later.

[0045] Furthermore, examples of useful synthetic resins and synthetic waxes for use in the natural colorant-containing toner of the present invention include polyvinyl chloride, polyacetal resins, polyamides, polycarbonates, polystyrene, polyacrylonitrile, polypropylene, polyethylene, fluororesins, polyurethanes, epoxy resins, silicone resins, polyesters, melamine resins, urea resins, phenolic resins, methacrylic resins, acrylic resins, alkyd resins, vinyl resins, or copolymers made from the respective monomer components of these resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes, and the like.

[0046] Furthermore, examples of useful natural or synthetic rubber materials that can be used in the natural colorant-containing toner of the present invention include natural rubber, chlorinated rubber, cyclized rubber, polyisobutylene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, polybutadiene rubber, butyl rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, silicone rubber, fluororubber, chlorohydrin rubber, and the like.

[0047] The binder resin used in the natural colorant-containing toner of the present invention is not limited to these, and a suitable mixture of two or more kinds of binder resin components may be used.

[0048] As the binder resin, a binder resin having a thermal fixing property is preferable, and it is more preferable to use styrene-based resins such as polystyrene and styrene-(meth)acrylic acid ester copolymers, polyester-based resins, and epoxy-based resins.

[0049] (Magnetic powder (C)) The magnetic powder used in the toner containing a natural dye of the present invention is not particularly limited, but one whose color does not affect the reproduced color can be preferably used, for example, iron oxide such as γ-iron oxide, yellow γ-iron oxide, ferrite, etc.; metals such as iron, cobalt, nickel, or alloys of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, organic magnetic materials such as poly-1,4-bis(2,2,6,6-tetramethyl-4-oxyl-4-piperidyl-1-oxyl)butadiene porphyrin metal complex, and mixtures thereof. Among them, yellow γ-iron oxide is more preferably used from the viewpoint of hue.

[0050] The average particle size of these magnetic powders is preferably in the range of 0.1 to 1 μm, more preferably 0.1 to 0.5 μm in terms of charging stability and hue. The amount of these powders contained in the natural colorant-containing toner is preferably 30 to 150% by mass relative to 100 parts by mass of the binder resin, more preferably 40 to 120% by mass relative to 100 parts by mass of the binder resin in terms of charging stability and hue.

[0051] (Anti-fading agent (D)) The discoloration inhibitor used in the natural colorant-containing toner of the present invention is not particularly limited, but may be, for example, at least one selected from the group consisting of heat-resistant anti-aging agents, metal oxides, and metal soaps.

[0052] Specific examples of the heat-resistant antioxidant include hydroquinone derivative-based antioxidants such as 2,5-di-t-amylhydroquinone, 2,5-di-t-butylhydroquinone, and hydroquinone monoethyl ether; methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, bis(4-hydroxyphenyl)sulfone, 2,2-bis(4-hydroxyphenyl)propane, 3,4-dihydroxy-4′-methyldiphenylsulfone, and 3,4-dihydroxy-4′-methyldiphenylsulfone. Dihydroxyphenyl-p-tolylsulfone, n-methyl gallate, n-ethyl gallate, n-propyl gallate, stearyl gallate, lauryl gallate, resorcinol, 1-oxy-3-methyl-4-isopropylbenzene, 2,6-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-sec-butylphenol, butylhydroxyanisole, 2,6-di-t- alkylated phenol and phenol derivative antioxidants such as butyl-α-dimethylamino-p-cresol, 2-(1-methylcyclohexyl)-4,6-dimethylphenol, styrenated phenol, and alkylated phenol; and phosphite ester antioxidants such as 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 4,4′-butylidenebis-(3-methyl-6-t-butylphenol), 2,2-thiobis(4′-hydroxy-3′,5′-di-t-butylphenyl)phosphite, tris(mixed mono- and di-nonylphenyl)phosphite, phenyl diisodecyl phosphite, diphenyl mono(2-ethylhexyl)phosphite, diphenyl monotridecyl phosphite, diphenyl isodecyl phosphite, diphenyl isooctyl phosphite, triphenyl phosphite, tris(tridecyl)phosphite, and tetraphenyl dipropylene glycol phosphite. These heat-resistant antioxidants may be used alone or in combination of two or more.Among these heat-resistant anti-aging agents, methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, bis(4-hydroxyphenyl)sulfone, 2,2-bis(4-hydroxyphenyl)propane, 3,4-dihydroxy-4'-methyldiphenylsulfone, 3,4-dihydroxyphenyl-p-tolylsulfone, n-methyl gallate, n-ethyl gallate, n-propyl gallate, stearyl gallate, lauryl gallate, resorcinol, and the like are preferred because they have excellent solubility in the binder resin (B).

[0053] Specific examples of the metal oxides include MgO, Al2O3, SiO2, Na2O, SiO2·MgO, SiO2, Al2O3, Al2O3·Na2O·CO2, MgO·Al2O3·CO2, etc. These metal oxides are used alone or in combination of two or more. Among these metal oxides, MgO, a mixture of MgO and SiO2 or Al2O3, Na2O, SiO2·MgO, SiO2·Al2O3, Al2O3·Na2O·CO2, MgO·Al2O3·CO2, etc. are particularly preferred because they have excellent anti-fading properties.

[0054] Specific examples of the metal soap include stearates such as lithium stearate, magnesium stearate, aluminum stearate, calcium stearate, strontium stearate, barium stearate, zinc stearate, cadmium stearate, and lead stearate; laurates such as cadmium laurate, zinc laurate, calcium laurate, and barium laurate; chlorostearates such as calcium chlorostearate, barium chlorostearate, and cadmium chlorostearate; barium 2-ethylhexylate, 2-ethylhexyl stearate, and the like. Examples of metal soaps include 2-ethylhexylates such as zinc ricinoleate, cadmium 2-ethylhexylate, and lead 2-ethylhexylate; ricinoleates such as barium ricinoleate, zinc ricinoleate, and cadmium ricinoleate; dibasic lead stearates such as 2PbO·Pb(C17H35COO)2; salicylates such as lead salicylate, zinc salicylate, tin salicylate, and chromium salicylate; tribasic lead maleates such as 3PbO·Pb(C4H2O4)H2O; and dibasic lead phthalates such as 2PbO·Pb(C8H4O4).These metal soaps can be used alone or in combination of two or more. Among these metal soaps, zinc stearate, calcium stearate, magnesium stearate, zinc laurate, zinc salicylate, zinc ricinoleate, barium ricinoleate, barium 2-ethylhexylate, etc. are preferred from the viewpoint of having a melting point suitable for use in a toner, etc.

[0055] The natural dye-containing toner produced using the water-insoluble dye composition of the present invention as a constituent component can be used as a one-component magnetic toner containing a magnetic material in the toner (color toner for magnetic one-component development), a non-magnetic one-component color toner not containing a magnetic material (color toner for non-magnetic one-component development), or a color toner for a two-component color developer mixed with a carrier (color toner for two-component development).

[0056] The one-component color magnetic toner can be composed of, for example, a colorant, a binder resin, a magnetic powder, and other additives such as a charge control agent and a release agent, in the same manner as commonly used toners.

[0057] The charge control agent is used for the purpose of adjusting the charge amount of the toner containing a natural colorant, and examples thereof include nigrosine dyes, quaternary ammonium salts, trimethylethane dyes, copper phthalocyanine, perylene, quinacridone, azo pigments, and metal complex azo dyes.

[0058] The release agent is used for the purpose of reinforcing the high-temperature offset resistance of the toner containing a natural colorant, and examples thereof include various waxes such as montan wax, carnauba wax, candelilla wax, rice wax, polypropylene wax, and polyethylene wax.

[0059] Since the toner containing the natural colorant of the present invention is a toner containing phycocyanin, it can exhibit a vivid blue or a color close to the vivid blue, and can affect human sensibility. Moreover, compared with a toner using only a synthetic colorant as a colorant, it can be a toner that is friendly to living things and the environment.

[0060] The use of the natural pigment-containing toner of the present invention is not limited to the expression of a specific color. However, since the natural pigment-containing toner of the present invention is a toner containing phycocyanin and exhibits a vivid blue or a color close to it, it is particularly preferable to use it as a cyan toner, among the common toner colors of black, cyan, yellow, and magenta. EXAMPLES

[0061] The present invention will be described in more detail below using production examples and formulation examples, but the present invention is not limited to the following embodiments. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0062] (Production Example 1: Water-insoluble pigment composition) In a 5L glass beaker, 46.3 g of aluminum chloride (III) hexahydrate (Kanto Chemical Co., Ltd.) was dissolved in 1200 mL of ion-exchanged water at room temperature (20 ° C), and 47.4 g of 48% sodium hydroxide aqueous solution (Kanto Chemical Co., Ltd.) was added to adjust the pH to 6.0 to prepare an aluminum hydroxide slurry. 37.5 g of Lina Blue G1 (DIC Life Tech Co., Ltd., trehalose 55%, phycocyanin pigment 40%, trisodium citrate 5%) was stirred and dissolved in 600 mL of ion-exchanged water, and the Lina Blue G1 aqueous solution was added little by little to the above aluminum hydroxide slurry at room temperature (20 ° C). After stirring for 1 hour, one drop of the blue slurry was dropped onto a filter paper, and the dropped area turned blue in a circular shape, and then a colorless and transparent liquid was observed to spread concentrically, confirming the insolubilization of phycocyanin. The blue slurry was filtered through a filter paper using a Nutsche filter and washed with 2 L of ion-exchanged water. The washings were colorless. The wet cake was a beautiful blue color. The wet cake was dried in a vacuum dryer (740 mmHg) at room temperature (20 ° C) for 12 hours, and then dried in a 50 ° C dryer for 5 hours to obtain 27.0 g of powder (1) in which aluminum hydroxide was coated with phycocyanin. The composition ratio of phycocyanin pigment and aluminum hydroxide in powder (1), calculated by subtracting the amount of aluminum hydroxide calculated from the amount of powder (1) from the yield of powder (1), was phycocyanin:aluminum hydroxide = 50:50 by mass ratio. The obtained powder (1) exhibited the same blue color as phycocyanin.

[0063] (Production Example 2: Water-insoluble pigment composition) In a 2L glass beaker, 25.5 g of aluminum chloride (III) hexahydrate (Kanto Chemical Co., Ltd.) was dissolved in 858 mL of ion-exchanged water at room temperature (20 ° C.), and a 5% aqueous sodium hydroxide solution prepared from a 48% aqueous sodium hydroxide solution (Kanto Chemical Co., Ltd.) was added to adjust the pH to 4.0 to obtain an aluminum hydroxide slurry. 49.7 g of Lina Blue G1 (DIC Life Tech Co., Ltd., trehalose 55%, phycocyanin pigment 40%, trisodium citrate 5%) was added in powder form and stirred at room temperature (20 ° C.) for 30 minutes. Next, a 5% aqueous sodium hydroxide solution was added to adjust the pH from 4.0 to 7.0, and aluminum hydroxide precipitated, resulting in a blue slurry. After stirring for 1 hour, a drop of the blue slurry was dropped onto a filter paper, and the area where the drop was applied turned blue in a circular shape, after which a colorless and transparent liquid was observed to spread concentrically, confirming the insolubilization of phycocyanin. The blue slurry was filtered through a filter paper using a Nutsche filter and washed with 2 L of ion-exchanged water to obtain a blue wet cake. The wet cake was dried in a vacuum dryer (740 mmHg) at room temperature (20 ° C) for 12 hours, and then dried in a 50 ° C dryer for 5 hours to obtain 28.1 g of powder (2) in which aluminum hydroxide was coated with phycocyanin. The composition ratio of phycocyanin pigment and aluminum hydroxide in powder (2), calculated by subtracting the amount of aluminum hydroxide calculated from the amount of powder (2) from the yield of powder (2), was phycocyanin: aluminum hydroxide = 70: 30 by mass ratio. The obtained powder (2) exhibited the same blue color as phycocyanin.

[0064] (Production Example 3: Water-insoluble pigment composition) In a 500 mL glass beaker, 1.0 g of Lina Blue G1 (DIC Life Tech Co., Ltd., trehalose 55%, phycocyanin pigment 40%, trisodium citrate 5%) was dissolved in 100 mL of ion-exchanged water at room temperature (20 ° C), and 3.8% hydrochloric acid prepared from hydrochloric acid (Kanto Chemical Co., Ltd.) was added to adjust the pH to 4.0. 1.6 g of ultrafine titanium dioxide (hydrophilic) (Orange Flower Co., Ltd.) was added to this solution and stirred at room temperature (20 ° C) for 30 minutes. When one drop of the blue slurry was dropped onto a filter paper, the dropped area turned blue in a circular shape, and then a colorless and transparent liquid was observed to spread concentrically, confirming the insolubilization of phycocyanin. The blue slurry was then filtered using a Nutsche filter and washed with ion-exchanged water until the pH of the washing solution became neutral, obtaining a blue wet cake. The wet cake was dried in a vacuum dryer (740 mmHg) at room temperature (20°C) for 12 hours, and then dried in a 50°C dryer for 5 hours to obtain 1.6 g of powder (3) in which aluminum hydroxide was coated with phycocyanin. The composition ratio of phycocyanin pigment and titanium oxide in powder (3), calculated from the amounts of Lina Blue G1 and titanium oxide charged, was phycocyanin:titanium oxide = 20:80 by mass. The obtained powder (3) exhibited the same blue color as phycocyanin.

[0065] (Production Example 4: Water-insoluble pigment composition) In a 1L glass beaker, 1.0 g of zinc oxide (Orange Flower Co., Ltd.) was added at room temperature (20°C), dispersed in 300 mL of ion-exchanged water, and 3.8% hydrochloric acid prepared from hydrochloric acid (Kanto Chemical Co., Ltd.) was added to adjust the pH to 4.0. At this time, zinc oxide became zinc chloride and dissolved in water. Next, 250 mg of Lina Blue G1 (DIC Life Tech Co., Ltd., trehalose 55%, phycocyanin pigment 40%, trisodium citrate 5%) was added to this solution and stirred at room temperature (20°C) for 30 minutes. Next, 5% aqueous sodium hydroxide solution was added to this solution, and the pH of the solution was adjusted to 7.0. At this time, zinc chloride became zinc hydroxide and precipitated, and the phycocyanin was stained to form a blue slurry. When one drop of the blue slurry was dropped onto a filter paper, the dropped area turned blue in a circular shape, and then a colorless and transparent liquid was observed to spread concentrically, confirming the insolubilization of phycocyanin. The blue slurry was then filtered using a Nutsche filter and washed with ion-exchanged water until the pH of the washings became neutral, obtaining a blue wet cake. The wet cake was dried in a vacuum dryer (740 mmHg) at room temperature (20°C) for 12 hours, and then dried in a 140°C dryer for 5 hours to convert zinc hydroxide to zinc oxide, obtaining 1.0 g of powder (4) in which zinc oxide was coated with phycocyanin. The composition ratio of the phycocyanin pigment and zinc oxide in powder (4), calculated from the amounts of Lina Blue G1 and zinc oxide charged, was phycocyanin:zinc oxide = 9:91 by mass. The obtained powder (4) exhibited the same blue color as phycocyanin.

[0066] (Comparative Manufacturing Example 1) Linablue G1 produced by the manufacturing method described in JP-A-11-299450 was used. 10 mg of Linablue G1 was added to 1.00 g of water and stirred for 5 minutes to produce dispersion (1). When one drop of dispersion (1) was dropped onto filter paper, it was observed that the blue liquid spread uniformly in a concentric shape around the drop. This indicates that Linablue G1 was dissolved in water in dispersion (1), and Linablue G1 was soluble in water.

[0067] As is clear from Production Examples 1 to 4 and Comparative Production Example 1, phycocyanin is water-soluble, but the pigment compositions containing phycocyanin and aluminum hydroxide, titanium oxide or zinc oxide were water-insoluble.

[0068] (Formulation Example 1: Toner containing natural pigments) Water-insoluble dye composition prepared in Preparation Example 1: 5.0 parts Styrene-acrylic acid copolymer 100.0 parts (Hymer SBM100, manufactured by Sanyo Chemical Industries, Ltd.) Yellow gamma-iron oxide 40.0 parts (MAPICOY-LOP, manufactured by Titan Kogyo Co., Ltd.) 0.1 parts 2,2-bis(4-hydroxyphenyl)propane

[0069] (Formulation Example 2: Toner containing natural pigments) Water-insoluble dye composition prepared in Preparation Example 1: 5.0 parts Styrene-acrylic acid copolymer 100.0 parts (Hymer SBM100, manufactured by Sanyo Chemical Industries, Ltd.) Yellow gamma-iron oxide 40.0 parts (MAPICOY-LOP, manufactured by Titan Kogyo Co., Ltd.) 3,4-dihydroxyphenyl-p-tolylsulfone 0.1 parts

[0070] (Formulation Example 3: Toner containing natural pigments) Water-insoluble dye composition prepared in Preparation Example 1: 5.0 parts Styrene-acrylic acid copolymer 100.0 parts (Hymer SBM100, manufactured by Sanyo Chemical Industries, Ltd.) Yellow gamma-iron oxide 40.0 parts (MAPICOY-LOP, manufactured by Titan Kogyo Co., Ltd.) Zinc stearate 0.1 parts

[0071] Any one of the components of the above Blend Examples 1 to 3 is kneaded in an extruder, then pulverized and classified in a jet mill to obtain a toner with an average particle size of 10 μm. This can be mixed with 1.0% hydrophobic silica (Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) to produce a toner containing natural colorants.

Claims

1. A toner containing a natural pigment, the toner comprising a colorant (A), a binder resin (B), a magnetic powder (C) and a discoloration inhibitor (D), 1. A toner containing a natural pigment, wherein the colorant (A) is a water-insoluble pigment composition containing phycocyanin.

2. 2. The toner according to claim 1, wherein the colorant (A) is a water-insoluble dye composition in which a metal hydroxide or oxide is coated with phycocyanin.

3. The composition of the metal hydroxide or oxide and phycocyanin is in the mass ratio:

3. The toner according to claim 2, wherein the ratio of metal hydroxide or oxide:phycocyanin is 99.9:0.1 to 10:

90.

4. 2. The toner according to claim 1, wherein the amount of the colorant (A) blended is 0.5 to 25 parts by mass based on 100 parts by mass of the binder resin (B).

5. 4. The water-insoluble pigment composition according to claim 1, wherein the phycocyanin is derived from a cyanobacterium of the genus Spirulina.

6. The water-insoluble pigment composition according to any one of claims 1 to 3, wherein the phycocyanin is Linablue G1 (trade name, manufactured by DIC Lifetech Co., Ltd.).

7. 2. The toner according to claim 1, wherein the anti-fading agent (D) is at least one selected from the group consisting of a heat-resistant anti-aging agent, a metal oxide and / or a metal soap.