Microcapsule pigment

Abstract

To provide a microcapsule pigment comprising a hydrophobically treated powder sufficiently encapsulated in a microcapsule.SOLUTION: A microcapsule pigment comprises at least a hydrophobically treated powder and a crystalline compound, both encapsulated therein, the compound having a melting point in the range of -40°C to 95°C and being selected from the group consisting of esters, ethers, and ketones. The hydrophobically treated powder is a powder hydrophobically treated with a surface treatment agent containing at least two types, including an N-acylamino acid or a salt thereof, and a compound selected from the group consisting of amino acids, esters, and metal complexes thereof.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to microcapsule pigments.

Background Art

[0002] Conventionally, pigments with a large specific gravity such as titanium oxide, and pigments such as carbon black that are somewhat difficult to disperse, are encapsulated in a water-insoluble medium having a specific gravity of less than 1 at 20°C, improving dispersibility and enabling arbitrary control of the specific gravity and particle size. Microcapsule pigments have been disclosed (see, for example, Patent Document 1). The above microcapsule pigments can be produced by an interfacial polymerization method in which an oily component (oily phase) containing a pigment (coloring component) is dispersed in an aqueous medium (aqueous phase) and a polymerization reaction is carried out at the interface between the oily phase and the aqueous phase. However, the pigment may not be retained in the oily phase and may migrate to the aqueous phase, resulting in insufficient encapsulation of the pigment in the microcapsules. In particular, titanium oxide with a hydrophilic surface easily migrates from the oily phase to the aqueous phase and cannot be encapsulated in the microcapsules, making it difficult to obtain the desired effect.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made based on the background art as described above, and aims to provide a microcapsule pigment in which a hydrophobized powder is sufficiently encapsulated in microcapsules.

Means for Solving the Problems

[0005] The present invention requires a microcapsule pigment comprising at least a hydrophobized powder and a crystalline compound selected from the group consisting of esters, ethers, and ketones having a melting point in the range of -40 to 95°C. Further, the hydrophobized powder is a powder hydrophobized by a surface treatment agent comprising at least two kinds selected from the group consisting of N-acyl amino acids or salts thereof and compounds selected from the group consisting of amino acids, esters, or metal complexes thereof. The ester contained in the surface treatment agent is a compound that can be obtained by reacting a saturated aliphatic alcohol having 12 to 20 carbon atoms with a monovalent or divalent carboxylic acid having 8 to 12 carbon atoms. Furthermore, a liquid composition comprising the microcapsule pigment and a vehicle is required. Also, the liquid composition is selected from the group consisting of printing inks, paints, inkjet inks, ultraviolet curable inks, writing instrument inks, coating tool inks, stamp inks, paints, cosmetics, and fiber coloring liquids. A writing instrument containing the writing instrument ink is required. Furthermore, a solid writing body or solid cosmetic comprising the microcapsule pigment and an excipient is required. Furthermore, a molding resin composition comprising a microcapsule pigment and a molding resin is required. Also, a molded body obtained by molding the molding resin composition is required. Furthermore, a laminate comprising a support and a colored layer containing the microcapsule pigment is required.

Advantages of the Invention

[0006] The present invention can provide a microcapsule pigment in which a hydrophobized powder is sufficiently encapsulated in microcapsules by encapsulating a hydrophobized powder and a crystalline compound selected from the group consisting of esters, ethers, and ketones having a specific melting point.

Embodiments for Carrying Out the Invention

[0007] The microcapsule pigment according to the present invention comprises a hydrophobized powder and a compound selected from the group consisting of crystalline esters, ethers, and ketones having a melting point in the range of -40 to 95°C as a medium, and a core substance obtained by dissolving or dispersing the hydrophobized powder in the medium is encapsulated by a wall film to form the microcapsule pigment. Hereinafter, the hydrophobized powder may be referred to as "hydrophobized powder" or "powder", and the compound selected from the group consisting of crystalline esters, ethers, and ketones having a melting point in the range of -40 to 95°C may be referred to as "medium". Hereinafter, each component constituting the microcapsule pigment according to the present invention will be described.

[0008] The microcapsule pigment according to the present invention contains a hydrophobized powder. Hereinafter, the powder to be hydrophobized may be referred to as "powder substrate". The powder substrate is not particularly limited, and inorganic powder or organic powder can be used.

[0009] Examples of the inorganic powder include extender pigments such as natural mica, sericite, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, calcium phosphate, aluminum oxide, magnesium oxide, aluminum hydroxide, barium sulfate, magnesium sulfate, silicic acid, anhydrous silicic acid, magnesium silicate, aluminum silicate, calcium silicate, barium silicate, silicon carbide, metal tungstate, clay, bentonite, zeolite, smectite, hydroxyapatite, ceramic powder, boron nitride, boron boride, and silica; coloring pigments such as titanium oxide, zinc oxide, cerium oxide, red iron oxide, yellow iron oxide, black iron oxide, chromium oxide, chromium hydroxide, ultramarine blue, ultramarine, carbon black, lake of tar pigment, and lake of natural pigment; fine particle titanium oxide, fine particle zinc oxide, fine particle iron oxide, fine particle cerium oxide, etc. having an average particle diameter of less than 0.1 μm; and lustrous pigments such as bismuth oxychloride, mica titanium, fish scale foil, and powder obtained by coating synthetic mica with titanium oxide.

[0010] Examples of the organic powder include wool powder, polyamide powder, polyester powder, polyethylene powder, polypropylene powder, polystyrene powder, polyurethane powder, benzoguanamine powder, polymethylbenzoguanamine powder, tetrafluoroethylene powder, polymethyl methacrylate powder, cellulose powder, silk powder, silicone powder, silicone rubber powder, styrene-acrylic acid copolymer, divinylbenzene-styrene copolymer, vinyl resin, urea resin, phenol resin, fluororesin, silicone resin, acrylic resin, melamine resin, epoxy resin, polycarbonate resin and other synthetic resin powders; microcrystalline fiber powder, starch powder, acylated lysine powder, long-chain alkyl metal phosphate powder, metal soap powder, C.I. Pigment Yellow, C.I. Pigment Orange, etc. Examples also include tar pigments such as Red No. 3, Red No. 10, Red No. 106, Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 226, Red No. 227, Red No. 228, Red No. 230, Red No. 401, Red No. 505, Yellow No. 4, Yellow No. 5, Yellow No. 202, Yellow No. 203, Yellow No. 204, Yellow No. 401, Blue No. 1, Blue No. 2, Blue No. 201, Blue No. 404, Green No. 3, Green No. 201, Green No. 204, Green No. 205, Orange No. 201, Orange No. 203, Orange No. 204, Orange No. 206, Orange No. 207; and natural pigments such as carmine, laccaic acid, kermesic acid, brazilein, crocin.

[0011] The powder base material is preferably a metal oxide, more preferably titanium oxide, zinc oxide, red iron oxide, yellow iron oxide, black iron oxide, fine particle titanium oxide, or fine particle zinc oxide. Since the surface of the metal oxide is generally terminated with hydroxyl groups and exhibits hydrophilicity, it is likely to transfer from the oil phase to the water phase during the process of preparing microcapsules. However, by hydrophobically treating the metal oxide, it becomes more likely to be retained in the oil phase, so it is preferably used as the powder base material.

[0012] The hydrophobized powder can be used as a coloring component or a non-coloring component of the microcapsule pigment. When it is a coloring component, it functions as a colorant for coloring the microcapsule pigment white, black, red, yellow, green, blue, etc. When it is a non-coloring component, the microcapsule pigment is transparent to translucent, and for example, it can be a microcapsule pigment that functions as an extender pigment for adjusting the fluidity, hiding power, gloss, and colorability of the ink.

[0013] The average particle diameter of the powder substrate is not particularly limited, but is preferably in the range of 0.01 to 3 μm. When the average particle diameter is within the above range, it can stably exist in a medium composed of a crystalline compound selected from the group consisting of esters, ethers, and ketones having a melting point in the range of -40 to 95°C described later, and a microcapsule pigment in which the hydrophobized powder is sufficiently encapsulated can be easily obtained. In addition, the average particle diameter of the powder substrate when it exists in a dispersed state in the medium is the value of the volume-based average particle diameter (median diameter) measured using a dynamic light scattering particle size distribution measuring device [manufactured by Microtrac Bell Corporation, product name: NANOTRAC FLEX] calibrated based on the numerical value measured using a standard sample or other measurement methods.

[0014] The hydrophobized powder according to the present invention is obtained by subjecting a powder substrate to surface treatment with one or more surface treatment agents selected from the group consisting of silicone-based compounds, N-acyl amino acids or their salts, fatty acids, hydrogenated lecithin, esters, alkyl silanes, alkyl phosphates, organic titanates, dextrin fatty acid esters, or fructooligosaccharide esters.

[0015] Examples of silicone compounds include cyclic methylhydrogen silicones such as methylhydrogenpolysiloxane, dimethiconol, one-terminal alkoxysilyl dimethylpolysiloxane, trimethylsiloxysilicic acid, and tetrahydrotetramethylcyclotetrasiloxane, acrylic silicone, silicone acrylate, amino-modified silicone, carboxy-modified silicone, phosphate-modified silicone, triethoxysilylethyl polydimethylsiloxyethyl dimethicone, triethoxysilylethyl polydimethylsiloxyethyl hexyldimethicone, and the like.

[0016] An N-acyl amino acid or a salt thereof is a compound in which an acyl group is introduced into the amino group of an amino acid or a salt thereof. Examples of amino acids include glutamic acid, alanine, glycine, sarcosine, proline, hydroxyproline, leucine, isoleucine, etc., and glutamic acid or aspartic acid is preferred. Examples of acyl groups include saturated fatty acids having 12 to 20 carbon atoms, and a stearoyl group or a lauroyl group is preferred. The carboxy group of the amino acid may be in the free form, or may be in the form of a salt with an alkali metal such as sodium or potassium, or an alkaline earth metal such as magnesium or calcium, and preferably a sodium salt. Preferred examples of N-acyl amino acids or salts thereof include disodium N-stearoylglutamate, sodium N-lauroylglutamate, sodium N-lauroylaspartate, and the like.

[0017] Examples of fatty acids include linear or branched saturated or unsaturated fatty acids having 12 to 22 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, palmitoleic acid, behenic acid, lignoceric acid, 2-ethylhexanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, isobehenic acid, etc. The fatty acid may be a metal salt.

[0018] Hydrogenated lecithin is obtained by hydrogenating natural or synthetic lecithin, and is hydrogenated lecithin with an iodine value of 15 or less, and is a glyceride having a phosphate group. Hydrogenated lecithin may be a metal salt.

[0019] Examples of the ester include compounds that can be obtained by reacting a saturated aliphatic alcohol having 12 to 20 carbon atoms with a monovalent or divalent carboxylic acid having 8 to 12 carbon atoms, and isostearyl sebacate is preferred. Alternatively, it may be a metal complex in which an ester is coordinately bonded to a metal atom. As the metal complex of the ester, isopropyl titanate triisostearate is preferred.

[0020] Examples of the alkylsilane include alkylalkoxysilanes having 1 to 18 carbon atoms, and examples thereof include methyltriethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, octadecyltriethoxysilane, aminopropyltriethoxysilane, and the like.

[0021] Alkyl phosphate is a monoester, diester, or triester of a long-chain alkyl alcohol and phosphoric acid, and examples thereof include lauryl phosphate, monocetyl phosphate, dicetyl phosphate, tricetyl phosphate, stearyl phosphate, and C 20-22 Phosphoric acid can be exemplified. Alkyl phosphate may be a metal salt.

[0022] Organic titanate is a compound having a Ti(OR)4 structure as a basic skeleton, and R is independently an alkyl group or an organic carbonyl group.

[0023] Dextrin fatty acid ester is an ester composed of dextrin and fatty acid or a derivative thereof, and fructooligosaccharide ester is an ester composed of fructooligosaccharide and fatty acid or a derivative thereof.

[0024] The surface treatment agent can be used alone or in combination of two or more. The surface treatment agent according to the present invention preferably comprises at least two kinds of N-acyl amino acid or its salt and a compound selected from the group consisting of amino acid, ester or its metal complex. This surface treatment agent has excellent affinity with a crystalline compound selected from the group consisting of esters, ethers, and ketones having a melting point in the range of -40 to 95°C described later, and the powder hydrophobized by this surface treatment agent stably exists in the medium. Therefore, during the preparation of the microcapsule pigment, the transfer from the oil phase to the aqueous phase is further suppressed, and since the hydrophobized powder is sufficiently encapsulated in the microcapsule, the specific gravity, particle diameter, etc. can be arbitrarily controlled, and a microcapsule pigment having a desired effect can be easily obtained. More preferably, the surface treatment agent is a surface treatment agent comprising at least two kinds of N-acyl amino acid or its salt and a compound obtained by reacting a saturated fatty alcohol having 12 to 20 carbon atoms as an ester with a monovalent or divalent carboxylic acid having 8 to 12 carbon atoms.

[0025] Examples of the surface treatment agent comprising at least two kinds of the above-mentioned N-acyl amino acid or its salt and a compound selected from the group consisting of amino acid, ester or its metal complex include a surface treatment agent containing sodium lauroyl glutamate and lysine (ASL treatment agent), a surface treatment agent containing disodium N-stearoyl glutamate and isostearyl sebacate (NHS treatment agent), a surface treatment agent containing sodium N-lauroyl aspartate and isopropyl titanate triisostearate (ASI treatment agent), and the like. Specific examples of the powder hydrophobized with the above surface treatment agent include ASL-treated powders such as ASL-1 TiO2CR-50, ASL-Red R-516P, ASL-Yellow LL-100P, and ASL-Black BL-100P manufactured by Daito Kasei Co., Ltd.; NHS-treated powders such as NHS-Titanium CR-50, NHS-Red R-516PS, NHS-Yellow LL-100P, NHS-Black BL-100P, NHS-Talc JA-46R, and NHS-Mica M-102 manufactured by Miyoshi Kasei Co., Ltd.; and ASI-treated powders such as ASI-1 TiO2CR-50, ASI-Red R-516P, ASI-Yellow LL-100P, ASI-Black BL-100P, and ASI-Talc JA-46R manufactured by Daito Kasei Co., Ltd.

[0026] The hydrophobized powder may be used in the form of a dispersion liquid preliminarily dispersed in an oily medium using a surfactant or a resin.

[0027] The microcapsule pigment according to the present invention encapsulates a compound selected from the group consisting of crystalline esters, ethers, and ketones having a melting point in the range of -40 to 95°C as a medium.

[0028] Examples of esters include esters having 13 or more carbon atoms in total, composed of a monovalent carboxylic acid and an aliphatic monohydric alcohol or a monohydric alcohol having an alicyclic ring; esters having 18 or more carbon atoms in total, composed of an aliphatic divalent or polyvalent carboxylic acid and an aliphatic monohydric alcohol or a monohydric alcohol having an alicyclic ring; esters having 18 or more carbon atoms in total, composed of an aliphatic divalent or polyvalent alcohol or a divalent or polyvalent alcohol having an alicyclic ring and a monovalent carboxylic acid; esters having 24 or more carbon atoms in total, composed of a divalent alcohol having an aromatic ring and a monovalent fatty acid; esters having 15 or more carbon atoms in total, composed of a monovalent carboxylic acid having an aromatic ring and an aliphatic monohydric alcohol or a monohydric alcohol having an alicyclic ring; esters having 14 or more carbon atoms in total, composed of a monovalent carboxylic acid having an aromatic ring and a monovalent alcohol having an aromatic ring; esters having 15 or more carbon atoms in total, composed of a monovalent carboxylic acid and a monovalent alcohol having an aromatic ring; esters having 16 or more carbon atoms in total, composed of a divalent carboxylic acid and a monovalent alcohol having an aromatic ring, and the like.

[0029] Also, the ester may be a compound represented by the following formula (1).

Chemical formula

Chemical formula

[0030] Furthermore, it may be a compound represented by the following formula (3).

Chemical formula

[0031] Furthermore, it may be a compound represented by the following formula (4).

Chemical formula

[0032] Furthermore, it may be a compound represented by the following formula (5).

Chemical formula

[0033] Furthermore, it may be a compound represented by the following formula (6).

Chemical formula

[0034] Furthermore, it may be a compound represented by the following formula (7). [Chemical formula] (In the formula, R represents any one of an alkyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, a cycloalkyl group, and an alkenyl group having 4 to 22 carbon atoms; X represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom; and n represents 0 or 1.)

[0035] Furthermore, it may be a compound represented by the following formula (8). [Chemical formula] (In the formula, R represents an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X represents any one of a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, and a halogen atom; Y represents a hydrogen atom or a methyl group; and Z represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, and a halogen atom.)

[0036] Furthermore, it may be a compound represented by the following formula (9). [Chemical formula] (In the formula, R represents any one of an alkyl group having 4 to 22 carbon atoms, an alkenyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, and a cycloalkyl group; X represents any one of a hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom; Y represents any one of a hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom; and n represents 0 or 1.)

[0037] Furthermore, it may be a compound represented by the following formula (10). [Chemical formula] (In the formula, R represents any one of an alkyl group having 3 to 18 carbon atoms, a cycloalkylalkyl group having 6 to 11 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, and an alkenyl group having 3 to 18 carbon atoms; X represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a halogen atom; Y represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, and a halogen atom.)

[0038] Furthermore, it may be a compound represented by the following formula (11).

Chemical formula

[0039] Furthermore, it may be a compound represented by the following formula (12).

Chemical formula

[0040] Examples of the ethers include aliphatic ethers having a total of 16 or more carbon atoms; ethers having an aromatic ring with a total of 11 or more carbon atoms, and the like.

[0041] Examples of the ketones include aliphatic ketones having a total of 10 or more carbon atoms; ketones having an aromatic ring or an alicyclic ring with a total of 10 or more carbon atoms, and the like.

[0042] The microcapsule pigment according to the present invention may encapsulate other components other than the aforementioned hydrophobized powder and the compound selected from the group consisting of crystalline esters, ethers, and ketones having a melting point in the range of -40 to 95°C, as long as the function is not affected. Examples of other components include colorants such as dyes or pigments (excluding hydrophobized powders); dispersants; antioxidants; ultraviolet absorbers; infrared absorbers; solubilizers; and various additives such as preservatives or fungicides.

[0043] Examples of dyes include acid dyes, basic dyes, direct dyes, oil-soluble dyes, and disperse dyes. Examples of pigments include inorganic pigments, organic pigments, lustrous pigments, fluorescent pigments, and phosphorescent pigments.

[0044] The microcapsule pigment according to the present invention may encapsulate a dispersant for the purpose of improving the dispersibility of the hydrophobized powder with respect to the compound selected from the group consisting of crystalline esters, ethers, and ketones having a melting point in the range of -40 to 95°C as a medium. Examples of dispersants include surfactants and polymer dispersants. Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Examples of polymer dispersants include, for example, polyvinyl butyral; polyvinyl ether; ketone resin; resins containing carboxy groups such as styrene-maleic acid copolymer, styrene-acrylic acid copolymer, and acrylic acid-sulfonic acid copolymer; hydroxyethyl cellulose and its derivatives; acrylic polymers; PO·EO adducts; hyperbranched polyesters; and amine-based oligomers of polyesters. Among these dispersants, those that dissolve in the compound selected from the group consisting of crystalline esters, ethers, and ketones having a melting point in the range of -40 to 95°C are preferred.

[0045] The microcapsule pigment according to the present invention may encapsulate an electron-donating color-forming compound and an electron-accepting compound. Thereby, a reversible thermochromic microcapsule pigment that reversibly changes color due to temperature changes can also be obtained. This is because a crystalline compound selected from the group consisting of esters, ethers, and ketones having a melting point in the range of -40 to 95°C according to the present invention acts as a reaction medium that determines the temperature at which the color-forming reaction of the electron-donating color-forming compound and the electron-accepting compound occurs. That is, by encapsulating the electron-donating color-forming compound and the electron-accepting compound, a reversible thermochromic composition comprising (a) an electron-donating color-forming compound, (b) an electron-accepting compound, and (c) a reaction medium that determines the temperature at which the color-forming reaction of the above components (a) and (b) occurs is contained in the microcapsules, and a reversible thermochromic microcapsule pigment can be obtained.

[0046] The following specifically describes the components (a) and (b).

[0047] Component (a), that is, the electron-donating color-forming organic compound, is a component that determines the color, and is a compound that donates electrons to component (b), which is a developer, and develops color.

[0048] Examples of the electron-donating color-forming organic compound include phthalide compounds, fluoran compounds, styrylnaphthyridine compounds, diazarhodamine lactone compounds, pyridine compounds, quinazoline compounds, bisquinazoline compounds, and the like. Examples of the phthalide compound include diphenylmethane phthalide compounds, phenylindolyl phthalide compounds, indolyl phthalide compounds, diphenylmethane azaphthalide compounds, phenylindolyl azaphthalide compounds, and their derivatives. Among these, phenylindolyl azaphthalide compounds and their derivatives are preferred. Examples of the fluoran compound include aminofluorane compounds, alkoxyfluorane compounds, and their derivatives.

[0049] The following exemplify the compounds that can be used for component (a). 3,3-bis(4-dimethylaminophenyl)-6-dimethylaminophthalide, 3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide, 3,3-bis(1-n-butyl-2-methylindol-3-yl)phthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(2-ethoxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-(2-n-hexyloxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-[2-ethoxy-4-(N-ethylanilino)phenyl]-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-(2-acetamido-4-diethylaminophenyl)-3-(1-propyl-2-methylindol-3-yl)-4-azaphthalide, 3,6-bis(diphenylamino)fluoran, 3,6-bis(N-phenyl-N-p-tolylamino)fluoran, 3,6-dimethoxyfluoran, 3,6-di-n-butoxyfluoran, 2-methyl-6-(N-ethyl-N-p-tolylamino)fluoran, 3-chloro-6-cyclohexylaminofluoran, 2-methyl-6-cyclohexylaminofluoran, 2-chloroamino-6-di-n-butylaminofluoran, 2-(2-chloroanilino)-6-di-n-butylaminofluoran, 2-(3-trifluoromethylanilino)-6-diethylaminofluoran, 2-(3-trifluoromethylanilino)-6-di-n-pentylaminofluoran, 2-dibenzylamino-6-diethylaminofluoran, 2-N-Methylanilino-6-(N-ethyl-N-p-tolylamino) fluoran, 1,3-Dimethyl-6-diethylamino fluoran, 2-Chloro-3-methyl-6-diethylamino fluoran, 2-Anilino-3-methyl-6-diethylamino fluoran, 2-Anilino-3-methoxy-6-diethylamino fluoran, 2-Anilino-3-methyl-6-di-n-butylamino fluoran, 2-Anilino-3-methoxy-6-di-n-butylamino fluoran, 2-Xylidino-3-methyl-6-diethylamino fluoran, 2-Anilino-3-methyl-6-(N-ethyl-N-p-tolylamino) fluoran, 6-Diethylamino-1,2-benzofluorane, 6-(N-Ethyl-N-isobutylamino)-1,2-benzofluorane, 6-(N-Ethyl-N-isopentylamino)-1,2-benzofluorane, 2-(3-Methoxy-4-dodecoxystyryl) quinoline, 2-Diethylamino-8-diethylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one, 2-Di-n-butylamino-8-di-n-butylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one, 2-Di-n-butylamino-8-diethylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one, 2-Di-n-butylamino-8-(N-ethyl-N-isoamylamino)-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one, 2-Di-n-butylamino-8-di-n-pentylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one, 4,5,6,7-Tetrachloro-3-(4-dimethylamino-2-methoxyphenyl)-3-(1-n-butyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-Tetrachloro-3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-Tetrachloro-3-(4-diethylamino-2-ethoxyphenyl)-3-(1-n-pentyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-Tetrachloro-3-(4-diethylamino-2-methylphenyl)-3-(1-ethyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone, 3′,6′-Bis〔phenyl(2-methylphenyl)amino〕spiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one, 3′,6′-Bis〔phenyl(3-methylphenyl)amino〕spiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one, 3′,6′-Bis〔phenyl(3-ethylphenyl)amino〕spiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one, 2,6-Bis(2′-ethyloxyphenyl)-4-(4′-dimethylaminophenyl)pyridine, 2,6-Bis(2′,4′-diethyloxyphenyl)-4-(4′-dimethylaminophenyl)pyridine, 2,6-Bis(2,4-diethyloxyphenyl)-4-〔4-bis(4-methyloxyphenyl)aminophenyl〕pyridine, 2-(4′-Dimethylaminophenyl)-4-methoxyquinazoline, 4,4′-Ethylenedioxy-bis〔2-(4-diethylaminophenyl)quinazoline〕

[0050] In addition, as fluorans, in addition to compounds having a substituent on the phenyl group forming the xanthene ring, compounds that have a substituent on the phenyl group forming the xanthene ring and also have a substituent (e.g., an alkyl group such as a methyl group, a halogen atom such as a chlorine atom) on the phenyl group forming the lactone ring and exhibit blue or black may also be used.

[0051] (B) component, that is, the electron-accepting compound, receives electrons from the (A) component and functions as a color former for the (A) component. Examples of the electron-accepting compound include compounds selected from a group of compounds having an active proton, a group of pseudo-acidic compounds [compounds that are not acids but act as acids in the reversible thermochromic composition to cause the (A) component to develop color], and a group of compounds having an electron hole. Among the above (B) components, compounds selected from the group of compounds having an active proton are preferred.

[0052] Examples of the group of compounds having an active proton include compounds having a phenolic hydroxy group and their derivatives, carboxylic acids and their derivatives, acidic phosphoric acid esters and their derivatives, azoazole compounds and their derivatives, 1,2,3-triazole and its derivatives, cyclic carbosulfimides, halohydrins having 2 to 5 carbon atoms, sulfonic acids and their derivatives, and inorganic acids. As the carboxylic acid and its derivatives, aromatic carboxylic acids and their derivatives, or aliphatic carboxylic acids having 2 to 5 carbon atoms and their derivatives are preferred. Examples of the group of pseudo-acidic compounds include metal salts of compounds having a phenolic hydroxy group, metal salts of carboxylic acids, metal salts of acidic phosphoric acid esters, metal salts of sulfonic acids, aromatic carboxylic acid anhydrides, aliphatic carboxylic acid anhydrides, mixed anhydrides of aromatic carboxylic acids and sulfonic acids, cycloolefin dicarboxylic acid anhydrides, urea and its derivatives, thiourea and its derivatives, guanidine and its derivatives, and halogenated alcohols. Examples of the group of compounds having an electron hole include borates, boric acid esters, and inorganic salts.

[0053] Among the above component (b), a compound having a phenolic hydroxy group is preferable because the thermochromic properties can be more effectively exhibited. Compounds having a phenolic hydroxy group widely include from monophenol compounds to polyphenol compounds. Further, bisphenol compounds, tris-phenol compounds, phenol-aldehyde condensation resins, etc. are also included therein. The compound having a phenolic hydroxy group preferably has at least two benzene rings. Further, the compound having a phenolic hydroxy group may have substituents such as an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group, a carboxy group and its ester or amide group, and a halogen atom.

[0054] Examples of the metal contained in the metal salt such as the compound having a phenolic hydroxy group include sodium, potassium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, lead, and molybdenum.

[0055] Examples of the compounds that can be used for the component (b) are given below. Phenol, o-Cresol, 4-n-p-Nonylphenol, 4-n-Octylphenol, 4-n-Dodecylphenol, 4-n-Stearylphenol, 4-Chlorophenol, 4-Bromophenol, 2-Phenylphenol, n-Butyl 4-Hydroxybenzoate, n-Octyl 4-Hydroxybenzoate, Resorcinol, 4-tert-Butylcatechol, 2,4-Dihydroxy-4'-tert-Butylbenzophenone, Dodecyl Gallate, 1,1-Bis(4-Hydroxyphenyl)ethane, 1,1-Bis(4-Hydroxyphenyl)propane, 1,1-Bis(4-Hydroxyphenyl)n-butane, 1,1-Bis(4-Hydroxyphenyl)n-pentane, 1,1-Bis(4-Hydroxyphenyl)n-hexane, 1,1-Bis(4-Hydroxyphenyl)n-heptane, 1,1-Bis(4-Hydroxyphenyl)n-octane, 1,1-Bis(4-Hydroxyphenyl)n-nonane, 1,1-Bis(4-Hydroxyphenyl)n-decane, 1,1-Bis(4-Hydroxyphenyl)n-dodecane, 1,1-Bis(4-Hydroxyphenyl)-2-Methylpropane, 1,1-Bis(4-Hydroxyphenyl)-3-Methylbutane, 1,1-Bis(4-Hydroxyphenyl)-3-Methylpentane, 1,1-Bis(4-Hydroxyphenyl)-2,3-Dimethylpentane, 1,1-Bis(4-Hydroxyphenyl)-2-Ethylbutane, 1,1-Bis(4-Hydroxyphenyl)-2-Ethylhexane, 1,1-Bis(4-Hydroxyphenyl)-3,7-Dimethyloctane, 1,1-Bis(4-Hydroxyphenyl)cyclohexane, 1,1-Bis(4-Hydroxyphenyl)-3,3,5-Trimethylcyclohexane, 1-Phenyl-1,1-Bis(4-Hydroxyphenyl)ethane, 2,2-Bis(4-Hydroxyphenyl)propane, 2,2-Bis(4-Hydroxyphenyl)n-butane, 2,2-Bis(4-Hydroxyphenyl)n-pentane, 2,2-Bis(4-Hydroxyphenyl)n-hexane, 2,2-Bis(4-Hydroxyphenyl)n-heptane, 2,2-Bis(4-Hydroxyphenyl)n-octane, 2,2-Bis(4-Hydroxyphenyl)n-nonane, 2,2-Bis(4-Hydroxyphenyl)n-decane, 2,2-Bis(4-Hydroxyphenyl)n-dodecane, 2,2-bis(4-hydroxyphenyl)ethyl propionate, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxyphenyl)-4-methylhexane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)butane, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, bis(2-hydroxyphenyl)methane, 4,4′-dihydroxydiphenyl sulfone, 4-isopropoxy-4′-hydroxydiphenyl sulfone, bis(4-hydroxyphenyl) sulfide, 1,1,1-tris(4-hydroxyphenyl)ethane, 4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bisphenol, 4,4′-[4-(4-hydroxyphenyl)-sec-butylidene]bis(2-methylphenol),

[0056] As the reversible thermochromic composition, a heat-decoloring type reversible thermochromic composition having a characteristic of a relatively small hysteresis width (ΔH) (ΔH = 1 to 7°C) described in Japanese Patent Publication No. Sho 51-44706, Japanese Patent Publication No. Sho 51-44707, Japanese Patent Publication No. Hei 1-29398, etc. can be used. The heat-decoloring type means decoloring by heating and coloring by cooling. This reversible thermochromic composition changes color before and after a predetermined temperature (color change point). It shows a decolored state in the temperature range above the high-temperature side color change point and a colored state in the temperature range below the low-temperature side color change point. Only one of the two states exists at room temperature, and the other state is maintained while the heat or cold applied to develop the state is being applied, but returns to the state presented at room temperature when the application of heat or cold stops.

[0057] As the reversible thermochromic composition, a heat-decoloring type reversible thermochromic composition having a large hysteresis width (ΔH = 8 to 80°C) described in, for example, Japanese Patent Publication No. 4-17154, Japanese Unexamined Patent Application Publication No. 7-179777, Japanese Unexamined Patent Application Publication No. 7-33997, Japanese Unexamined Patent Application Publication No. 8-39936, and Japanese Unexamined Patent Application Publication No. 2005-1369 can be used. The heat-decoloring type means decoloring upon heating and coloring upon cooling. In this reversible thermochromic composition, the shape of the curve plotting the change in coloring density due to temperature change is significantly different when the temperature is increased from a lower temperature side than the discoloration temperature range and when the temperature is decreased from a higher temperature side than the discoloration temperature range, and the coloring state in the temperature range below the complete coloring temperature t1 or the decoloring state in the high temperature range above the complete decoloring temperature t4 has color memory in a specific temperature range (the temperature range between the coloring start temperature t2 and the decoloring start temperature t3 (substantially two-phase holding temperature range)).

[0058] When the microcapsule pigment according to the present invention encapsulates the reversible thermochromic composition having the above-described color memory, specifically, as the reversible thermochromic composition, the complete coloring temperature t1 is set to a temperature that can only be obtained in a freezer, a cold region, etc., and the complete decoloring temperature t4 is set to a temperature range obtained from frictional heat by a friction body, a heating body such as a hair dryer that is close at hand. By specifying the ΔH value to be 40 to 100°C, it can function effectively to maintain the color exhibited in the normal state (daily living temperature range).

[0059] The temperature that can only be obtained in a freezer, a cold region, etc. is -50 to 0°C, preferably -40 to -5°C, more preferably -30 to -10°C. The temperature obtained from a heating body such as a hair dryer that is close at hand is 50 to 95°C, preferably 50 to 90°C, more preferably 60 to 80°C.

[0060] As the reversible thermochromic composition, a heat-coloring type reversible thermochromic composition using a gallic acid ester described in, for example, Japanese Patent Publication No. 51-44706 and Japanese Unexamined Patent Application Publication No. 2003-253149 can also be used. The heat-coloring type means coloring upon heating and decoloring upon cooling.

[0061] The reversible thermochromic composition is a solid solution having the above components (a), (b), and (c) as essential components, and the ratio of each component depends on the concentration, the color change temperature, the color change form, and the type of each component. Generally, the component ratio at which desired properties can be obtained is in the range of 0.1 to 100, preferably 0.1 to 50, more preferably 0.5 to 20 of component (b), and 1 to 800, preferably 5 to 200, more preferably 10 to 100 of component (c) with respect to 1 of component (a) (all of the above ratios are in parts by mass).

[0062] In the above reversible thermochromic microcapsule pigment, when the hydrophobized powder according to the present invention exhibits white, in the colored state of the reversible thermochromic composition, the white by the hydrophobized powder and the color by the reversible thermochromic composition are mixed, and the microcapsule pigment exhibits a pastel-colored color. Further, in the decolored state of the reversible thermochromic composition, it exhibits white by the hydrophobized powder. That is, the reversible thermochromic microcapsule pigment exhibits a behavior of reversibly changing from a pastel-colored color to white due to a temperature change. Further, in the above reversible thermochromic microcapsule pigment, when the hydrophobized powder according to the present invention exhibits a color, in the colored state of the reversible thermochromic composition, the color by the hydrophobized powder and the color by the reversible thermochromic composition are mixed, and the microcapsule pigment exhibits a color due to the color mixture. Further, in the decolored state of the reversible thermochromic composition, it exhibits the color by the hydrophobized powder. That is, the reversible thermochromic microcapsule pigment exhibits a behavior of reversibly changing from color (1) to color (2) due to a temperature change. In the above, "colored" means a color other than white.

[0063] The microcapsule pigment according to the present invention may contain a photochromic material that changes color upon irradiation with light. This color change may be reversible or irreversible, but a reversible photochromic material is preferred because repeated color changes can be exhibited depending on the presence or absence of light irradiation. Examples of the reversible photochromic material include photochromic compounds.

[0064] As the photochromic compound, there are conventionally known spirooxazine derivatives, spiropyran derivatives, naphthopyran derivatives, etc. that develop color when irradiated with sunlight, ultraviolet light, or purple to blue light with a peak emission wavelength in the range of 400 to 495 nm, and fade when the irradiation is stopped. For example, the compounds described in JP-A-2021-120493 and WO 2020 / 137469 can be exemplified. Furthermore, a photochromic compound having photomemory properties (color memory type photochromism) can also be used. Examples of such photochromic compounds include diarylethene derivatives, etc., and for example, the compounds described in JP-A-2021-120493 can be exemplified.

[0065] The microcapsule pigment according to the present invention can be made into a reversible photochromic microcapsule pigment that reversibly changes color depending on the presence or absence of light irradiation by encapsulating a photochromic compound.

[0066] In the above reversible photochromic microcapsule pigment, when the hydrophobized powder according to the present invention exhibits white, in the colored state of the photochromic compound, the white due to the hydrophobized powder and the color due to the photochromic compound are mixed, and the microcapsule pigment exhibits a pastel-colored appearance. Also, in the decolored state of the photochromic compound, it exhibits white due to the hydrophobized powder. That is, the reversible photochromic microcapsule pigment exhibits a behavior of reversibly changing from a pastel color to white depending on the presence or absence of light irradiation. Also, in the above reversible photochromic microcapsule pigment, when the hydrophobized powder according to the present invention exhibits a color, in the colored state of the photochromic compound, the color due to the hydrophobized powder and the color due to the photochromic compound are mixed, and the microcapsule pigment exhibits a color due to the color mixture. Also, in the decolored state of the photochromic compound, it exhibits the color due to the hydrophobized powder. That is, the reversible photochromic microcapsule pigment exhibits a behavior of reversibly changing from a color (1) to a color (2) depending on the presence or absence of light irradiation. In the above, "colored" means a color other than white.

[0067] The microcapsule pigment according to the present invention can be produced by a microencapsulation method. Examples of the microencapsulation method include an interfacial polymerization method, an in Situ polymerization method, an in-liquid curing coating method, a phase separation method from an aqueous solution, a phase separation method from an organic solvent, a melt dispersion cooling method, an air suspension coating method, a spray drying method, and the like. The present invention is characterized in that when preparing the microcapsule pigment, the hydrophobized powder hardly transfers from the oil phase to the aqueous phase, and a microcapsule pigment in which the powder is sufficiently encapsulated can be easily obtained. Therefore, a microencapsulation method in which an oil phase (oil component) containing a hydrophobized powder is dispersed in an aqueous phase (aqueous medium) to prepare a microcapsule pigment is suitable. Examples thereof include an interfacial polymerization method and an in Situ polymerization method.

[0068] On the surface of the microcapsule pigment according to the present invention, a secondary resin film can be further provided according to the purpose to impart durability or to modify the surface characteristics for practical use.

[0069] The microcapsule pigment according to the present invention preferably has a mass ratio of core substance: wall film of 7:1 to 1:1. When the mass ratio of the core substance to the wall film is within the above range, a decrease in color density and vividness can be prevented. More preferably, the mass ratio of core substance: wall film is 6:1 to 1:1.

[0070] The average particle diameter of the microcapsule pigment is not particularly limited, but is preferably in the range of 0.01 to 50 μm, more preferably 0.1 to 30 μm, and even more preferably 0.5 to 20 μm. When the average particle diameter exceeds 50 μm, it lacks dispersion stability or processability when blended into ink, paint, or resin. On the other hand, when the average particle diameter is less than 0.01 μm, it becomes difficult to exhibit high-concentration color development. When the microcapsule pigment according to the present invention is used in the ink for writing instruments described below, the average particle size is preferably in the range of 0.01 to 5 μm, more preferably 0.05 to 4 μm, still more preferably 0.1 to 3 μm, and particularly preferably 0.5 to 3 μm. When the average particle size exceeds 5 μm, it becomes difficult to obtain good ink ejection performance when used in a writing instrument. On the other hand, when the average particle size is less than 0.01 μm, it becomes difficult to exhibit high-concentration color development.

[0071] The measurement of the average particle size was performed by determining the particle region using image analysis type particle size distribution measurement software [manufactured by Mountech Co., Ltd., product name: MacView], calculating the equivalent diameter of the projected area circle (Heywood diameter) from the area of the particle region, and measuring it as the average particle size of the particles equivalent to an equal-volume sphere based on that value. When the particle size of all particles or most particles exceeds 0.2 μm, it is also possible to measure the average particle size of the particles equivalent to an equal-volume sphere by the Coulter method using a particle size distribution measuring device [manufactured by Beckman Coulter, Inc., product name: Multisizer 4e]. Furthermore, based on the numerical values measured using the above software or the measuring device by the Coulter method, the volume-based particle size and average particle size may be measured using a laser diffraction / scattering type particle size distribution measuring device [manufactured by Horiba, Ltd., product name: LA-960V2] that has been calibrated.

[0072] The microcapsule pigment according to the present invention can be made into an ink composition (hereinafter sometimes referred to as "ink") by dispersing it in a vehicle containing at least one of water and an organic solvent and various additives as necessary. It can be used as a liquid composition such as printing ink for screen printing, offset printing, process printing, gravure printing, coater, tampo printing, etc. / brush painting, spray coating, electrostatic coating, electroplating coating, flow coating, roller coating, dipping coating, etc. / inkjet ink / ultraviolet curable ink / ink for marking pens, ballpoint pens, fountain pens, felt-tip pens, etc. / ink for applicators / ink for stamps / art paints / cosmetics / coloring liquid for fibers.

[0073] Various additives can be incorporated into the liquid composition. Examples of additives include resins, crosslinking agents, curing agents, desiccants, plasticizers, viscosity modifiers, dispersants, ultraviolet absorbers, antioxidants, light stabilizers, anti-settling agents, smoothing agents, gelling agents, defoamers, matting agents, penetrants, pH adjusters, foaming agents, coupling agents, humectants, antifungal agents, preservatives, rust preventives, and the like.

[0074] Examples of the vehicle for writing ink used in writing instruments include an oil-based vehicle containing an organic solvent or an aqueous vehicle containing water and, if necessary, an organic solvent. When the vehicle is an aqueous vehicle, a water-soluble organic solvent compatible with water can be incorporated into the writing ink. The water-soluble organic solvent suppresses the evaporation of moisture from the ink, prevents fluctuations in the specific gravity of the vehicle, and has the effect of stably dispersing the microcapsule pigment in the ink.

[0075] Examples of the organic solvent include ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, thiodiethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, and the like.

[0076] When the writing ink contains a water-soluble organic solvent, the content of the water-soluble organic solvent relative to the total mass of the ink composition is not particularly limited, but is preferably in the range of 1 to 40% by mass, more preferably 5 to 30% by mass, and still more preferably 10 to 25% by mass.

[0077] The ink for writing instruments can be blended with a thickener, which can suppress the aggregation or sedimentation of microcapsule pigments and the bleeding of writing, so that good writing can be formed. As the thickener, conventionally known substances can be used, but it is preferable to use a substance (shear-thinning viscosity-imparting agent) that can impart shear-thinning viscosity to the ink composition. The ink containing a shear-thinning viscosity-imparting agent (shear-thinning ink) has a high viscosity and is difficult to flow in a stationary state or when the stress is low, and easily becomes low-viscosity when an external stress is applied. Therefore, during non-writing, ink leakage can be prevented, ink separation or backflow can be prevented, and it is easy to improve the ink ejection stability from the pen tip during writing. In particular, when such an ink composition is used in a writing instrument (ballpoint pen) having a ballpoint pen tip as the pen tip, since it has a high viscosity during standing when no shear stress is applied, the ink composition is stably held in the ballpoint pen. For this reason, during writing, a strong shear stress is applied to the ink composition by the rotation of the ball, and the ink composition near the ball is more likely to become lower-viscosity, so that the ink ejection stability can be improved.

[0078] When the ink for writing instruments contains a thickener, the content rate of the thickener with respect to the total mass of the ink composition is not particularly limited, but is preferably in the range of 0.1 to 20% by mass.

[0079] Examples of the shear-thinning viscosity-imparting agent include water-soluble polysaccharides, polymers having a molecular weight of 100,000 to 150,000 mainly composed of alkyl esters of methacrylic acid, poly-N-vinylcarboxylic acid amide crosslinked products, benzylidene sorbitol and its derivatives, benzylidene xylitol and its derivatives, alkali-thickening type acrylic resins, crosslinkable acrylic acid polymers, inorganic fine particles, nonionic surfactants having an HLB value of 8 to 12, metal salts or amine salts of dialkyl sulfosuccinic acid, etc. The shear-thinning viscosity-imparting agent can be used alone or in combination of two or more.

[0080] Examples of water-soluble polysaccharides include xanthan gum, welan gum, zeta-carrageenan, diutan gum, macrohomoopsis gum, succinoglycan, guar gum, locust bean gum and its derivatives, hydroxyethyl cellulose, alkyl alginates, glucomannan, and carbohydrates having a gelling ability extracted from seaweeds such as agar or carrageenan.

[0081] A dispersant can be incorporated into the ink for writing instruments to enhance the dispersibility of the microcapsule pigments. Examples of dispersants include synthetic resins such as polyvinylpyrrolidone, polyvinyl butyral, polyvinyl ether, styrene-maleic acid copolymer, ketone resin, hydroxyethyl cellulose and its derivatives, styrene-acrylic acid copolymer, acrylic polymers, PO·EO adducts, and amine-based oligomers of polyester.

[0082] When the ink for writing instruments contains a dispersant, the content of the dispersant relative to the total mass of the ink composition is not particularly limited, but is preferably in the range of 0.01 to 2% by mass, more preferably 0.1 to 1.5% by mass. By having the content within the above range, it becomes easier to improve the dispersibility of the microcapsule pigments in the ink.

[0083] When the ink for writing instruments is used in a writing instrument (ballpoint pen) equipped with a ballpoint pen tip, a lubricant can also be incorporated into the ink for writing instruments. The lubricant can improve the lubricity between the ball seat provided inside the tip body and the ball provided at the front end of the tip body, easily prevent wear of the ball seat, and improve the writing feel.

[0084] Examples of lubricants include higher fatty acids such as oleic acid; nonionic surfactants having long-chain alkyl groups; polyether-modified silicone oils; trialkyl phosphite esters such as tris(alkoxycarbonylmethyl ester) thiophosphite and tris(alkoxycarbonylethyl ester) thiophosphite, phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, phosphoric acid diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, or phosphoric acid ester-based surfactants such as metal salts, ammonium salts, amine salts, and alkanolamine salts of these phosphoric acid esters.

[0085] For writing instrument inks, other additives such as polymer flocculants, water-soluble resins, specific gravity adjusters, surfactants, pH adjusters, wetting agents, resin particles, rust preventives, wetting agents, defoamers, viscosity adjusters, preservatives or fungicides, bubble absorbers, defoamers, antioxidants, and ultraviolet absorbers can be blended as necessary.

[0086] In writing instrument inks, the content of the microcapsule pigment relative to the total mass of the ink composition is not particularly limited, but is preferably in the range of 5 to 40% by mass, more preferably 10 to 40% by mass, and still more preferably 10 to 30% by mass. When the content is within the above range, a desired color density can be obtained and a decrease in ink flowability can be prevented.

[0087] The method for producing the ink composition can be carried out by any conventionally known method. Specifically, the ink composition can be produced by blending the above-described components in required amounts and stirring with various stirrers such as a propeller stirrer, a homodisper, or a homomixer, or by dispersing with various dispersers such as a bead mill.

[0088] Examples of writing instruments that can contain the writing instrument ink include various writing instruments such as ballpoint pens, marking pens, fountain pens, brush pens, and calligraphy pens.

[0089] When the ink for writing instruments is used in a ballpoint pen, the structure and shape of the ballpoint pen itself are not particularly limited. For example, it can be used by filling a ballpoint pen refill or a ballpoint pen equipped with a ballpoint pen tip and an ink filling mechanism.

[0090] The ballpoint pen tip consists of a tip body and a ball provided at the front end of the tip body. The ballpoint pen tip is, for example, a tip formed by holding a ball in a ball holding portion obtained by pressing and deforming the vicinity of the tip of a tip body made of a metal pipe inward from the outer surface, a tip formed by holding a ball in a ball holding portion formed by cutting with a drill or the like on a tip body made of a metal material, a tip provided with a resin ball seat inside a metal or plastic tip body, or a tip in which the ball held by the above tip is biased forward by a spring body, etc. can be exemplified.

[0091] The materials of the tip body and the ball are not particularly limited, and examples include cemented carbide (carbide), stainless steel, ruby, ceramic, resin, rubber, etc. Furthermore, the ball can also be subjected to a surface treatment such as DLC coating.

[0092] The diameter of the ball is generally in the range of 0.2 to 3 mm, preferably 0.2 to 2 mm, more preferably 0.2 to 1.5 mm, and even more preferably 0.2 to 1 mm.

[0093] Examples of the ink filling mechanism include an ink container that can directly fill ink. For the ink container, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, nylon, etc., or a metal tubular body can be used.

[0094] A ballpoint pen refill (hereinafter sometimes referred to as a "refill") can be formed by connecting a ballpoint pen tip directly or via a connecting member to an ink container and directly filling the ink container with ink. A ballpoint pen can be formed by housing this refill in a barrel.

[0095] An ink backflow prevention body is filled at the rear end of the ink filled in the ink container. Examples of the ink backflow prevention body include a liquid plug or a solid plug.

[0096] The liquid plug is composed of a non-volatile liquid and / or a hardly volatile liquid. For example, petrolatum, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefin, oligomer or co-oligomer of α-olefin, dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, polyether-modified silicone oil, fatty acid-modified silicone oil, etc. can be exemplified. The non-volatile liquid and / or the hardly volatile liquid can be used singly or in combination of two or more.

[0097] It is preferable to add a thickening agent to the non-volatile liquid and / or the hardly volatile liquid to thicken it to a suitable viscosity. Examples of the thickening agent include clay-based thickening agents such as silica with a hydrophobic surface treatment, particulate silica with a methylated surface treatment, aluminum silicate, swelling mica, bentonite and montmorillonite with a hydrophobic treatment; fatty acid metal soaps such as magnesium stearate, calcium stearate, aluminum stearate, zinc stearate; dextrin-based compounds such as tribenzylidene sorbitol, fatty acid amide, amide-modified polyethylene wax, hydrogenated castor oil, fatty acid dextrin; cellulose-based compounds, etc.

[0098] Examples of the solid plug include solid plugs made of polyethylene, polypropylene, polymethylpentene, etc. As the ink backflow prevention body, a solid plug and the above-described liquid plug can also be used in combination.

[0099] Alternatively, by using the shaft cylinder itself as an ink filling mechanism, directly filling ink into the shaft cylinder, and attaching a ball pen tip to the front end of the shaft cylinder, a ball pen equipped with a ball pen tip and an ink filling mechanism can also be formed.

[0100] When the ink filled in the ink filling mechanism has a low viscosity, the ball pen equipped with a ball pen tip and an ink filling mechanism may further include an ink supply mechanism for supplying the ink filled in the ink filling mechanism to the pen tip.

[0101] The ink supply mechanism is not particularly limited. For example, (1) a mechanism that includes an ink guiding core made of a fiber bundle or the like as an ink flow regulator and supplies ink to the pen tip through this; (2) a mechanism that includes a comb-shaped ink flow regulator and supplies ink to the pen tip through this; (3) a mechanism that supplies ink to the pen tip through a pen core in which a number of disk bodies are arranged in parallel with a comb-shaped interval, and slit-shaped ink guiding grooves and ventilation grooves wider than the grooves that vertically penetrate the disk bodies in the axial direction are provided, and an ink guiding core for guiding ink from the ink filling mechanism to the pen tip is arranged at the axis center, etc. can be mentioned.

[0102] The material of the pen core is not particularly limited as long as it is a synthetic resin that can be injection-molded into a structure in which a number of disk bodies are comb-shaped. Since it has high moldability and it is easy to obtain pen core performance, acrylonitrile-butadiene-styrene copolymer (ABS resin) is preferably used.

[0103] Specifically, as the configuration of a ballpoint pen for accommodating writing implement ink, examples include: (1) a ballpoint pen having an ink container filled with ink inside a shaft cylinder, with a ballpoint pen tip connected to the ink container directly or via a connecting member, and an ink backflow prevention body filled at the end face of the ink; (2) a ballpoint pen in which ink is directly filled inside the shaft cylinder, and having a mechanism for supplying the ink to the pen tip by interposing an ink flow regulator in the form of a comb-shaped groove or an ink guiding core made of a fiber bundle; (3) a ballpoint pen in which ink is directly filled inside the shaft cylinder, and having a mechanism for supplying the ink to the pen tip via the above pen core, etc.

[0104] When the writing implement ink is used in a marking pen, the structure and shape of the marking pen itself are not particularly limited. For example, it can be used by filling a marking pen refill or a marking pen equipped with a marking pen tip and an ink filling mechanism.

[0105] Examples of the marking pen tip include conventionally widely used porous members with communicating pores having a porosity generally in the range of 30 to 70%, such as resin-processed bodies of fibers, fusion-processed bodies of heat-meltable fibers, felt bodies, or extrusion-molded bodies of synthetic resin having a plurality of ink outlet holes extending in the axial direction. One end is processed into a shape suitable for the purpose, such as a bullet shape, a rectangular shape, a chisel shape, etc., and is put into practical use.

[0106] Examples of the ink filling mechanism include an ink storage body capable of filling ink. The ink storage body is a fiber aggregate in which crimped fibers are aggregated in the longitudinal direction, and is configured by being incorporated in a covering body such as a plastic cylinder or film, and adjusting the porosity to generally be in the range of 40 to 90%.

[0107] A marking pen can be formed by accommodating an ink storage body impregnated with ink inside a shaft cylinder, and connecting a marking pen tip directly or via a connecting member to the shaft cylinder so as to connect to the ink storage body.

[0108] Further, an ink reservoir containing an ink-impregnated ink storage body is housed, and a marking pen tip is connected to the ink storage body so as to be connected to the ink storage body directly or via a connecting member, whereby a marking pen refill (hereinafter sometimes referred to as a "refill") can be formed. A marking pen can be formed by housing this refill in a shaft cylinder.

[0109] As the ink reservoir, for example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, nylon, or a metal tubular body is used.

[0110] A marking pen having a marking pen tip and an ink filling mechanism may further include an ink supply mechanism for supplying the ink filled in the ink filling mechanism to the pen tip.

[0111] The ink supply mechanism is not particularly limited. For example, in addition to the ink supply mechanism provided in the above-described ballpoint pen, a mechanism including an ink flow rate regulator by a (4) valve mechanism and supplying ink to the pen tip by opening the valve can be mentioned. As the valve mechanism, a conventionally widely used pumping type that is opened by pressing the tip can be used, and it is preferably set to a spring pressure that can be pressed and opened by the writing pressure.

[0112] When the marking pen includes an ink supply mechanism, as the ink filling mechanism, in addition to the above-described ink storage body, an ink reservoir that can be directly filled with ink can be used. Further, the shaft cylinder itself may be used as the ink filling mechanism to directly fill the ink.

[0113] Specifically, as the configuration of a marking pen for accommodating ink for writing instruments, there are: (1) a marking pen in which an ink storage body composed of a fiber aggregate impregnated with ink is accommodated in a shaft cylinder, and a marking pen tip composed of a fiber processed body or a resin molded body with a capillary gap formed is connected to the shaft cylinder directly or via a connecting member so that the ink storage body and the tip are connected; (2) a marking pen in which ink is directly filled in the shaft cylinder, and a mechanism for supplying ink to the pen tip is provided with an ink flow regulator in the form of a comb-shaped groove or an ink guiding core composed of a fiber bundle or the like interposed as the ink flow regulator; (3) a marking pen in which ink is directly filled in the shaft cylinder, and a mechanism for supplying ink to the pen tip via the above pen core is provided; (4) a marking pen provided with a valve mechanism that opens by pressing the tip and an ink storage body, and the ink storage body is directly filled with ink, etc. can be exemplified.

[0114] When a ballpoint pen or a marking pen according to the present invention directly fills ink, in order to facilitate the redispersion of microcapsule pigments, a stirring body such as a stirring ball for stirring the ink can also be incorporated in the ink storage body or the shaft cylinder into which the ink is filled. Examples of the shape of the stirring body include a spherical body, a rod-shaped body, etc. The material of the stirring body is not particularly limited, and for example, metal, ceramic, resin, glass, etc. can be exemplified.

[0115] Writing instruments such as ballpoint pens or marking pens according to the present invention can also be in the form of an ink cartridge as a detachable structure. In this case, after using up the ink accommodated in the ink cartridge of the writing instrument, the writing instrument can be used again by replacing it with a new ink cartridge.

[0116] As the ink cartridge, one that also serves as a shaft cylinder that constitutes the writing instrument when connected to the writing instrument body, or one that covers and protects the shaft cylinder (rear shaft) after being connected to the writing instrument body is used. In the latter case, in addition to being used as a single ink cartridge, in a writing instrument before use, it may be one in which the writing instrument body and the ink cartridge are connected, or one in which the ink cartridge in the shaft cylinder is accommodated in a non-connected state so that the user of the writing instrument can connect the ink cartridge in the shaft cylinder and start using it at the time of use.

[0117] In the writing instrument such as a ballpoint pen or a marking pen according to the present invention, by providing a cap that is attached so as to cover the pen tip (writing tip portion) to make it a capped writing instrument, it is possible to prevent the writing tip portion from being contaminated or damaged. In addition, in a writing instrument such as a ballpoint pen or a marking pen in which a refill is accommodated in the shaft cylinder, an extending and retracting mechanism that allows the writing tip portion to extend and retract from the shaft cylinder can be provided in the shaft cylinder to make it an extending and retracting type writing instrument, and it is possible to prevent the writing tip portion from being contaminated or damaged.

[0118] Any retractable writing instrument can be used as long as the writing tip portion is accommodated in the shaft cylinder in a state where it is exposed to the outside air and the writing tip portion protrudes from the shaft cylinder opening by the operation of the retracting mechanism. In addition, it can also be a composite type retractable writing instrument in which a plurality of refills are accommodated in the shaft cylinder, and the writing tip portion of any one of the refills is retracted and extended from the shaft cylinder opening by the operation of the retracting mechanism.

[0119] As the protruding and retracting mechanism, for example, (1) a side slide type protruding and retracting mechanism in which an operating part (clip) that can move in the front-rear direction from the rear side wall of the shaft cylinder protrudes radially outward, and the writing tip is protruded and retracted from the front end opening of the shaft cylinder by sliding the operating part forward; (2) a rear end knock type protruding and retracting mechanism in which the writing tip is protruded and retracted from the front end opening of the shaft cylinder by pressing an operating part provided at the rear end of the shaft cylinder forward; (3) a side knock type protruding and retracting mechanism in which the writing tip is protruded and retracted from the front end opening of the shaft cylinder by pressing an operating part protruding from the outer surface of the side wall of the shaft cylinder radially inward; (4) a rotary type protruding and retracting mechanism in which the writing tip is protruded and retracted from the front end opening of the shaft cylinder by rotating an operating part at the rear of the shaft cylinder, etc. can be exemplified.

[0120] The form of the ballpoint pen or the marking pen is not limited to the above-described configuration. In addition to attaching chips of different forms or attaching chips that derive inks of different color tones or hues, a composite writing instrument (such as a double-ended type or a pen tip extending type) that attaches chips of different forms and the color tones or hues of the inks derived from each chip are different may also be used.

[0121] When the microcapsule pigment contains a reversible thermochromic microcapsule pigment, the handwriting formed on the writing surface using a writing instrument containing the ink for writing instruments can be discolored by rubbing with a finger or by using a heating tool or a cooling tool.

[0122] Examples of the heating tool include an energization heating discoloration tool equipped with a resistance heating element such as a PTC element, a heating discoloration tool filled with a medium such as warm water, a heating discoloration tool using steam or laser light, the application of a hair dryer, etc. Since it can be discolored by a simple method, a friction member and a friction body are preferable. Examples of the cooling tool include an energization thermoelectric discoloration tool using a Peltier element, a thermoelectric discoloration tool filled with a refrigerant such as cold water or ice pieces, a cold storage agent, the application of a refrigerator or a freezer, etc.

[0123] As the friction member and the friction body, elastic bodies such as elastomers and plastic foams that are rich in elasticity and can generate appropriate friction and frictional heat during rubbing are preferred, but plastic molded bodies, stones, woods, metals, fabrics, etc. can also be used. In addition, although the handwriting may be rubbed using a common eraser used for erasing handwriting with a pencil, since eraser chips are generated during rubbing, the above-described friction member and friction body that hardly generate eraser chips are preferably used.

[0124] Examples of the materials of the friction member and the friction body include silicone resin, styrene-ethylene-butadiene-styrene block copolymer (SEBS resin), etc. Since the resin tends to adhere to the portion erased by rubbing in the case of silicone resin and the handwriting tends to be repelled when writing repeatedly, SEBS resin is more preferably used.

[0125] The above friction member or friction body may be a member of any shape separate from the writing instrument, but it can be made excellent in portability by providing it on the writing instrument. Further, a writing instrument set can also be obtained by combining a writing instrument and a friction member or friction body of any shape separate from the writing instrument.

[0126] In the case of a writing instrument provided with a cap, the location where the friction member or friction body is provided is not particularly limited. For example, the cap itself can be formed of a friction member, the shaft cylinder itself can be formed of a friction member, or when a clip is provided, the clip itself can be formed of a friction member, or a friction member or friction body can be provided at the tip (top) of the cap or the rear end of the shaft cylinder (the portion where the writing tip is not provided).

[0127] In the case of a writing instrument provided with a retractable mechanism, the location where the friction member or friction body is provided is not particularly limited. For example, the shaft cylinder itself can be formed of a friction member, or when a clip is further provided, the clip itself can be formed of a friction member, or a friction member or friction body can be provided near the opening of the shaft cylinder, the rear end of the shaft cylinder (the portion where the writing tip is not provided), or the knock portion.

[0128] The ink composition according to the present invention can be used as a stamp ink. Examples of the stamp vehicle used in the stamp ink include an oily vehicle containing an organic solvent, or an aqueous vehicle containing water and, if necessary, an organic solvent.

[0129] Examples of the organic solvent include castor oil fatty acid alkyl esters, cellosolve solvents, alkylene glycol solvents, ester solvents, hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents, ketone solvents, propionic acid solvents, highly polar solvents, or a mixed solvent thereof.

[0130] When the vehicle is an aqueous vehicle, a water-soluble organic solvent compatible with water can be blended in the stamp ink.

[0131] When the stamp ink contains a water-soluble organic solvent, the content of the water-soluble organic solvent relative to the total mass of the ink composition is not particularly limited, but is preferably in the range of 30 to 60% by mass, more preferably 30 to 55% by mass, and even more preferably 40 to 50% by mass. When the content is within the above range, the ink does not dry or absorb moisture, and a clear image is easily obtained.

[0132] A thickener can be blended in the stamp ink, which can suppress the aggregation or sedimentation of the microcapsule pigment and suppress the bleeding of the image, so that a clear image can be formed. As the thickener, a conventionally known substance can be used, but an alkali-soluble type acrylic emulsion is preferred. When an alkali-soluble type acrylic emulsion is used as the thickener, the pH of the stamp ink is preferably in the range of 6 to 11, more preferably 7 to 11, and even more preferably 7 to 10.

[0133] In addition to the above, if necessary, additives such as binder resin, surfactant, pH adjuster, wetting agent, resin particles, rust inhibitor, wetting agent, defoaming agent, viscosity modifier, preservative or fungicide, air bubble absorber, defoaming agent, antioxidant, ultraviolet absorber, etc. can also be incorporated into the stamp ink.

[0134] In the stamp ink, the content of the microcapsule pigment relative to the total mass of the ink composition is not particularly limited, but is preferably in the range of 10 to 40% by mass, more preferably 10 to 35% by mass, and even more preferably 10 to 30% by mass. If the content exceeds 40% by mass, the dispersion stability of the microcapsule pigment in the ink tends to decrease. On the other hand, if the content is less than 10% by mass, the color density tends to decrease.

[0135] The stamp ink can be used as stamp pad ink or stamp ink provided with an impression material having continuous pores. For example, a stamp pad can be obtained by impregnating the ink into a stamp pad and supplying the ink to the printing surface of the stamp in contact therewith. Also, a stamp can be obtained by impregnating the ink into the impression material of a stamp provided with an impression material having continuous pores.

[0136] The above-mentioned stamp can form an image on various surfaces to be stamped. Further, when the microcapsule pigment contains a reversible thermochromic microcapsule pigment, the image formed on the surface to be stamped using the stamp containing the stamp ink can be discolored by rubbing with a finger or by the aforementioned heating tool or cooling tool. Since it can be discolored by a simple method, as the heating tool, the aforementioned friction member and friction body are preferred.

[0137] The above-mentioned friction member or friction body may be a member of any shape separate from the stamp, but it can be made to have excellent portability by providing it on the stamp. Also, a stamp set can be obtained by combining a stamp and a friction member or friction body of any shape separate from the stamp.

[0138] When the ink composition according to the present invention is used by printing or coating, the material of the support to be printed or coated is not particularly limited and all are effective. For example, paper, synthetic paper, fiber, fabric, synthetic leather, leather, plastic, glass, ceramic, metal, wood, stone, etc. can be exemplified. can be given. The shape of the support is not limited to a flat shape and may be uneven.

[0139] By providing a colored layer made of a liquid composition on the support, a laminate (printed matter) can be obtained. When the microcapsule pigment contains a reversible thermochromic microcapsule pigment or a reversible photochromic microcapsule pigment, a color-changing laminate (color-changing printed matter) provided with a color-changing layer made of a reversible thermochromic liquid composition or a reversible photochromic liquid composition can be obtained on the support. This laminate (printed matter) reversibly changes color depending on the temperature change or the presence or absence of light irradiation. In addition, in the case where a non-color-changing colored layer (non-color-changing colored image) is previously formed on the support, by providing a color-changing layer on the non-color-changing colored layer, the non-color-changing colored layer (non-color-changing colored image) can be hidden and revealed by the color-changing layer depending on the temperature change or the presence or absence of light irradiation, and the aspect of the change can be further diversified.

[0140] By melt-blending and molding the microcapsule pigment according to the present invention with an excipient, it can be used as a solid form for coating and can be used as a solid writing implement or a solid cosmetic. Examples of the solid writing implement include crayons, pencil leads, mechanical pencil leads, solid gel markers, etc. Examples of the solid cosmetic include foundations, eyeliners, eyebrows, eyeshadows, lipsticks, etc.

[0141] Examples of the excipient used for the solid writing implement include wax, gelling agent, clay mineral, etc. Among the excipients, it is preferable to contain at least one selected from the group consisting of polyolefin wax, sucrose fatty acid ester, and dextrin fatty acid ester because it is easy to improve the handwriting density.

[0142] The content rate of the excipient relative to the total mass of the solid writing body is not particularly limited, but is preferably in the range of 0.2 to 70% by mass, more preferably 0.5 to 40% by mass. By the content rate being within the above range, it is easy to obtain the shape as a solid writing body, and the writing density of the solid writing body is likely to be high.

[0143] In the solid writing body, additives such as fillers, binder resins, viscosity modifiers, preservatives or fungicides, antibacterial agents, antioxidants, ultraviolet ray inhibitors, lubricants, and fragrances can also be blended as necessary.

[0144] The solid writing body may be used alone as a writing body, or may be a core-sheath structure (double core) provided with a shell that covers the outer peripheral surface using it as an inner core.

[0145] The above-mentioned solid writing body can write on various writing surfaces. Further, when the microcapsule pigment contains a reversible thermochromic microcapsule pigment, the writing formed on the writing surface using the solid writing body can be discolored by rubbing with a finger or by the above-mentioned heating tool or cooling tool. Since it can be discolored by a simple method, as the heating tool, the above-mentioned friction member and friction body are preferable.

[0146] The above-mentioned friction member or friction body may be a member of an arbitrary shape separate from the outer packaging of the solid writing body or the solid writing instrument in which the solid writing body is housed in an outer packaging container, but by providing it on the outer packaging of the solid writing body or the solid writing instrument, it can be made excellent in portability. Specifically, forms in which the outer packaging is in the shape of a pencil such as wood or paper, or a crayon, and a friction member is provided, etc. can be mentioned. Further, a solid writing body set can also be obtained by combining the solid writing body with a friction member or friction body of an arbitrary shape separate from the solid writing body.

[0147] The microcapsule pigment according to the present invention can be melt-blended with a thermoplastic resin, a thermosetting resin, waxes, etc. to be in the form of pellets, powders, or pastes, and can be used as a resin composition for molding. Using the above-described resin composition for molding, molded articles in the form of three-dimensional objects of arbitrary shapes, films, sheets, plates, filaments, rods, pipes, etc. can be obtained by means such as general-purpose injection molding, extrusion molding, blow molding, casting molding, etc. Also, toners and powder coatings can be obtained by melt-blending with thermoplastic resins.

[0148] Specific examples of products using the microcapsule pigment according to the present invention include the following. (1) Toys Dolls and animal-shaped toys; hairs for dolls and animal-shaped toys; accessories for dolls such as doll houses and furniture, clothes, hats, bags, shoes, etc.; accessory toys; stuffed toys; drawing toys; picture books for toys; puzzle toys such as jigsaw puzzles; building block toys; block toys; clay toys; fluid toys; tops; kites; musical instrument toys; cooking toys; gun toys; capture toys; background toys; mask toys; toys imitating vehicles, animals, plants, buildings, foods, etc. (2) Clothing Clothes such as T-shirts, trainers, blouses, dresses, swimsuits, raincoats, ski wear, etc.; footwear such as shoes; shoelaces; shoe components such as insoles, outsoles, midsoles, etc.; cloth items around the body such as handkerchiefs, towels, tablecloths, etc.; gloves; neckties; hats; sports wear, etc. (3) Interior decorations Carpets, curtains, curtain cords, tablecloths, floor mats, cushions, zabutons, chair covers, sheets, mats, picture frames, artificial flowers, photo stands, etc. (4) Furniture Bedding such as futons, pillows, mattresses, etc.; chairs; stools; sofas; lighting fixtures; heating and cooling appliances, etc. (5) Ornaments Rings, bracelets, tiaras, necklaces, earrings, hairpins, false nails, ribbons, scarves, watches, glasses, key holders, etc. (6) Stationery Writing instruments, stamping tools, erasers, blotting papers, rulers, notebooks, pads, adhesive tapes, etc. (7) Daily necessities Toiletries such as paper diapers; bath supplies; toothbrushes; cold or heat insulation bags; warmers; thermometers; watering cans; buckets; cleaning tools; cosmetics such as lipsticks, eyeshadows, foundations, eyeliners, eyebrows, nail polishes, hair dyes, nail paints, etc. (8) Kitchen supplies Cooking utensils, lunch boxes, water bottles, cups, plates, chopsticks, spoons, forks, pots, frying pans, coasters, pot holders, lunch mats, etc. (9) Others Calendars, labels, cards, recording materials, various printed materials for anti-counterfeiting; books such as picture books; sports supplies such as gloves, protectors, nets, etc.; bags; packaging containers; embroidery threads; fishing gear; musical instruments; cold storage agents; bag items such as wallets; umbrellas; vehicles; buildings; temperature detection indicators; teaching aids such as picture books, maps, etc.; pet supplies: medical or nursing care supplies such as supporters, bandages, band-aids, etc., electronic devices such as smartphones, earphones, speakers, etc.

Example

[0149] Examples are shown below. Unless otherwise specified, "parts" in the examples indicate "parts by mass".

[0150] Example 1 Preparation of microcapsule pigments As the hydrophobized powder, a composition consisting of 30 parts of hydrophobized titanium oxide [manufactured by Miyoshi Kasei Co., Ltd., product name: NHS-Titanium CR-50] and 50 parts of stearyl capric acid (melting point: 39°C) as the medium was put into a mixed solution consisting of 35 parts of an aromatic isocyanate prepolymer as the wall film forming material and 40 parts of a co-solvent, and then emulsified and dispersed in an 8% aqueous polyvinyl alcohol solution. After continuing stirring while heating, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was continued to prepare a microcapsule dispersion. A microcapsule pigment was obtained from the above microcapsule dispersion by centrifugation.

[0151] The microcapsule pigments of Examples 2 to 4 were prepared in the same manner as in Example 1, except that the types and amounts of the materials to be blended were changed to those described in Table 1 below.

[0152] Comparative Example 1 Preparation of Microcapsule Pigment As the powder not subjected to hydrophobic treatment (hereinafter sometimes referred to as "non-hydrophobically treated powder"), 30 parts of titanium oxide [manufactured by Teika Co., Ltd., product name: JR-405] and 50 parts of stearyl capric acid (melting point: 39°C) as a medium were used. The resulting composition was put into a mixed solution consisting of 35 parts of an aromatic isocyanate prepolymer as a wall film forming material and 40 parts of a co-solvent, emulsified and dispersed in an 8% aqueous polyvinyl alcohol solution, and stirred while heating. Then, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was continued to prepare a microcapsule dispersion. A microcapsule pigment was obtained from the above microcapsule dispersion by centrifugation.

[0153] The microcapsule pigment of Comparative Example 2 was prepared in the same manner as Comparative Example 1, except that the types and amounts of the materials to be blended were changed to those described in Table 1 below.

[0154] [Table 1]

[0155] The materials in Table 1 are as follows. Titanium oxide hydrophobically treated with a surface treatment agent (NHS treatment agent) containing sodium N-stearoylglutamate and isostearyl sebacate [manufactured by Miyoshi Kasei Co., Ltd., product name: NHS-Titanium CR-50] Titanium oxide hydrophobically treated with a surface treatment agent (ASL treatment agent) containing sodium N-lauroylglutamate and lysine [manufactured by Daito Kasei Co., Ltd., product name: ASL-1 TiO2CR-50] Red iron oxide hydrophobically treated with a surface treatment agent (ASI treatment agent) containing sodium N-lauroylaspartate and isopropyl titanate triisostearate [manufactured by Daito Kasei Co., Ltd., product name: ASI-Red R-516P] Titanium oxide [manufactured by Teika Co., Ltd., product name: JR-405] B-1 Stearyl caprate (Melting point: 39°C) B-2 4-Benzyloxyphenylethyl caprate (Melting point: 64°C) B-3 Cetyl 2-ethylhexanoate (Melting point: -5°C) C-1 Hyperbranched polyester [manufactured by BYK Chemie Japan Co., Ltd., product name: DISPER BYK-2152 (solid content: 100%)]

[0156] [Possibility of microencapsulation] 20 parts of each microcapsule pigment obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were mixed and dispersed with 80 parts of water to prepare a pigment dispersion. Next, each pigment dispersion was uniformly coated on high-quality paper using a bar coater (#2) and dried to obtain a printed matter as a test sample. The coated portion of the test sample was observed with a scanning electron microscope (SEM) [manufactured by Hitachi High-Technologies Corporation, product name: TM-4000II] to confirm whether the hydrophobized powder or the non-hydrophobized powder was encapsulated in the microcapsules. The results were as shown in Table 1 above, and the evaluation "A" was regarded as passing. A: No hydrophobized powder or non-hydrophobized powder was confirmed outside the microcapsules, and the hydrophobized powder or non-hydrophobized powder was sufficiently encapsulated in the microcapsules. B: A large amount of hydrophobized powder or non-hydrophobized powder was confirmed outside the microcapsules, and the hydrophobized powder or non-hydrophobized powder was not sufficiently encapsulated in the microcapsules.

[0157] Example 5 Preparation of microcapsule pigment As the hydrophobized powder, 30 parts of hydrophobized titanium oxide (manufactured by Miyoshi Kasei Co., Ltd., product name: NHS-Titanium CR-50), 1.5 parts of 3-(2-hexyloxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide as the (a) component, 5 parts of 2,2-bis(4-hydroxyphenyl)hexafluoropropane and 3 parts of 1,1-bis(4-hydroxyphenyl)-2-ethylhexane as the (b) component, and 50 parts of 4-benzyloxyphenylethyl caprate (melting point: 64°C) as the medium [(c) component] were put into a mixed solution composed of 35 parts of an aromatic isocyanate prepolymer and 40 parts of a cosolvent as the wall film forming material. After that, it was emulsified and dispersed in an 8% aqueous polyvinyl alcohol solution, and stirring was continued while heating. Then, 2.5 parts of a water-soluble aliphatic modified amine were added, and stirring was further continued to prepare a microcapsule dispersion. A microcapsule pigment was obtained from the above microcapsule dispersion by centrifugation.

[0158] Example 6 The microcapsule pigment of Example 6 was prepared in the same manner as in Example 5, except that the types and amounts of the materials to be blended were changed to those described in Table 2 below.

[0159] [Table 2]

[0160] The materials in Table 2 are the materials shown below. A-1 and A-3 are the same as above. Ba-1 3-(2-hexyloxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide Bb-1 2,2-bis(4-hydroxyphenyl)hexafluoropropane Bb-2 1,1-bis(4-hydroxyphenyl)-2-ethylhexane Bc-1 is the same as B-3 above.

[0161] [Possibility of Microencapsulation] Twenty parts of each microcapsule pigment obtained in Examples 5 and 6 were mixed and dispersed with 80 parts of water to prepare a pigment dispersion. Subsequently, each pigment dispersion was uniformly coated on fine paper using a bar coater (#2) and dried to obtain a printed matter as a test sample. The coated portion of the test sample was observed with a scanning electron microscope (SEM) [manufactured by Hitachi High-Tech Corporation, product name: TM-4000II] to confirm whether the hydrophobized powder was encapsulated in the microcapsules. The results were as shown in Table 2 above, and the evaluation "A" was regarded as passing. A: No hydrophobized powder was confirmed outside the microcapsules, and the hydrophobized powder was sufficiently encapsulated in the microcapsules. B: A large amount of hydrophobized powder was confirmed outside the microcapsules, and the hydrophobized powder was not sufficiently encapsulated in the microcapsules.

[0162] [Confirmation of reversible thermochromic function] Forty parts of each microcapsule pigment obtained in Examples 5 and 6 were mixed with 52 parts of an ethylene-vinyl acetate copolymer resin emulsion, 5 parts of a thickener, and 3 parts of a leveling agent to prepare an ink. The above ink was used to screen-print a solid pattern on fine paper to obtain a test sample. Each of the above test samples was set in the measurement part of a color difference meter [manufactured by Tokyo Denshoku Co., Ltd., product name: TC-3600], the temperature of the sample part was raised and lowered at a rate of 2 °C / min, and the lightness value was measured as the color density at each temperature to create a color density-temperature curve. The complete color development temperature t1 and the complete color fading temperature t4 were determined from the color density-temperature curve. Subsequently, for each test sample, when heated to a temperature equal to or higher than the complete color fading temperature t4 of the microcapsule pigment, it was visually confirmed whether the microcapsule pigment changed from the colored state to the colorless state and the test sample changed color. Then, when cooled to a temperature equal to or lower than the complete color development temperature t1 of the microcapsule pigment, it was visually confirmed whether the microcapsule pigment changed from the colorless state to the colored state and the test sample changed color. And it was evaluated whether the microcapsule pigment had a reversible thermochromic function. The evaluation results are as described in Table 2 above, and an evaluation of "A" was considered a pass. A: The microcapsule pigment reversibly changed from a colored state to a decolorized state due to temperature changes and had a reversible thermochromic function. B: The microcapsule pigment did not reversibly change from a colored state to a decolorized state due to temperature changes and did not have a reversible thermochromic function. Also, the colors of the microcapsule pigment in the colored state and the decolorized state when the temperature of each test sample was changed were described in Table 2 above.

[0163] The microcapsule pigment of Example 5 exhibits a pastel blue color in which the blue color of the reversible thermochromic composition and the white color of the hydrophobized powder (hydrophobized titanium oxide) as a coloring component are mixed because the reversible thermochromic composition is in a colored state and turns blue in the temperature range below the complete coloring temperature t1. Also, in the temperature range above the complete decoloring temperature t4, the reversible thermochromic composition is in a decolorized state and becomes colorless, so it exhibits the white color of the hydrophobized powder. That is, the microcapsule pigment reversibly changes from pastel blue to white due to temperature changes. The microcapsule pigment of Example 6 exhibits a purple color in which the blue color of the reversible thermochromic composition and the red color of the hydrophobized powder (hydrophobized iron oxide) as a coloring component are mixed because the reversible thermochromic composition is in a colored state and turns blue in the temperature range below the complete coloring temperature t1. Also, in the temperature range above the complete decoloring temperature t4, the reversible thermochromic composition is in a decolorized state and becomes colorless, so it exhibits the red color of the hydrophobized powder. That is, the microcapsule pigment reversibly changes from purple to red due to temperature changes.

[0164] Application Example 1 Production of a writing instrument (marking pen) 23 parts of the microcapsule pigment of Example 1 were mixed into an aqueous vehicle composed of 0.4 part of an acrylic polymer dispersant [product name: Solsperse 43000, manufactured by Lubrizol Japan Ltd.], 0.2 part of a preservative (sodium 2-pyridinethiol 1-oxide) [product name: Sodium Omadine, manufactured by Ark Chemical Japan Co., Ltd.], 0.2 part of a preservative (3-iodo-2-propynyl N-butylcarbamate) [product name: Glycacil 2000, manufactured by Ark Chemical Japan Co., Ltd.], 30 parts of glycerin, and 46.2 parts of water to prepare a liquid composition which is an ink for writing instruments. The above ink for writing instruments was impregnated into an ink storage body in which polyester slivers were coated with a synthetic resin film, and the ink storage body was housed in a shaft cylinder made of polypropylene resin. A resin-processed pen body (chisel type) made of polyester fiber was assembled in a connected state to the tip of the shaft cylinder via a resin holder, and a cap was attached to produce a marking pen. Using the above marking pen, at room temperature (20 °C) environment, on a black paper of A4 size [manufactured by Nagatoya Shoten Co., Ltd., product name: Color Paper A4 Medium Thickness Mouth (thickness: 0.09 mm, density: 80 g / m 2 )], when handwritten notes were made, handwriting (characters) with a certain concentration and line width were obtained. Also, this handwriting concealed the writing surface and was good handwriting rich in concealability. In addition, since the microcapsule pigment used in the above marking pen sufficiently encapsulates the hydrophobically treated powder as a coloring component, even after the writing instrument was stored for a long time, only the hydrophobically treated powder was suppressed from separating and aggregating. When writing on the paper surface again at room temperature (20 °C) environment using the writing instrument stored for a long time, good white handwriting (characters) with a certain concentration and line width were obtained, similar to the initial handwriting.

[0165] Application Example 2 Production of Printed Matter 40 parts of the microcapsule pigment of Example 4 were uniformly mixed into an aqueous vehicle composed of 50 parts of a urethane resin emulsion, 3 parts of a leveling agent, and 1 part of a thickening agent to prepare a liquid composition which is an ink for printing. A solid pattern was printed on the surface of the white synthetic paper by screen printing using the above printing ink, dried and cured to provide a colored layer, thereby obtaining a laminate. In the above laminate, the colored layer was a distinct red color. In addition, since the microcapsule pigment used in the above printing ink sufficiently encapsulates the hydrophobically treated powder as the coloring component, even after long-term storage of the printing ink, only the hydrophobically treated powder is separated and aggregated. This was suppressed. When a printed matter was produced by the same method as above using the printing ink after long-term storage, the colored layer had a uniform density, and no roughness due to aggregation of the hydrophobically treated powder was observed. The same result as the printed matter produced using the printing ink before long-term storage was obtained.

[0166] Application Example 3 Production of a reversible thermochromic writing instrument (reversible thermochromic marking pen) 23 parts of the microcapsule pigment of Example 6 (pre-cooled to -20°C or lower and developed into purple) were mixed into an aqueous vehicle consisting of 0.4 part of an acrylic polymer dispersant [manufactured by Nippon Lubrizol Corporation, product name: Solsperse 43000], 0.2 part of a preservative (sodium 2-pyridinethiol 1-oxide) [manufactured by Ark Chemical Japan Co., Ltd., product name: Sodium Omadine], 0.2 part of a preservative (3-iodo-2-propynyl N-butylcarbamate) [manufactured by Ark Chemical Japan Co., Ltd., product name: Glycacil 2000], 30 parts of glycerin, and 46.2 parts of water to prepare a reversible thermochromic liquid composition which is an ink for writing instruments. The above ink for writing instruments was impregnated into an ink storage body in which a polyester sliver was coated with a synthetic resin film, housed in a shaft cylinder made of polypropylene resin, and a resin-processed pen body (chisel type) made of polyester fiber was assembled in a connected state to the tip of the shaft cylinder via a resin holder, and a cap was attached to produce a marking pen. Note that an SEBS resin was attached as a friction member to the rear end portion of the shaft cylinder. When writing on paper at room temperature (20°C) using the above-mentioned marking pen, purple handwriting (characters) with a certain concentration and line width was obtained. When the handwriting was rubbed with a friction member, the reversible thermochromic composition was decolorized and the handwriting became red, and this state could be maintained unless it was cooled to -20°C or lower. When the paper was placed in a freezer and cooled to -20°C or lower, the handwriting showed a color-changing behavior of turning purple again, and this color-changing behavior could be repeatedly reproduced. In addition, since the microcapsule pigment used in the above-mentioned marking pen sufficiently encapsulates the hydrophobically treated powder as a coloring component, even after the writing instrument is stored for a long period of time, only the hydrophobically treated powder is suppressed from separating and aggregating. When writing on paper again at room temperature (20°C) using the writing instrument after long-term storage, good purple handwriting (characters) with a certain concentration and line width was obtained as in the initial handwriting.

Claims

1. A microcapsule pigment comprising at least a hydrophobically treated powder and a crystalline compound selected from the group consisting of esters, ethers, and ketones having a melting point in the range of -40 to 95°C.

2. The hydrophobically treated powder is an N-acyl amino acid or a salt thereof, and a compound selected from the group consisting of an amino acid, an ester, or a metal complex thereof and is a powder hydrophobically treated with a surface treatment agent containing at least two kinds thereof. The microcapsule pigment according to Claim 1.

3. The ester contained in the surface treatment agent is a compound obtainable by reacting a saturated aliphatic alcohol having 12 to 20 carbon atoms with a monovalent or divalent carboxylic acid having 8 to 12 carbon atoms. The microcapsule pigment according to Claim 2.

4. A liquid composition comprising the microcapsule pigment according to any one of Claims 1 to 3 and a vehicle.

5. The liquid composition according to Claim 4, selected from the group consisting of printing ink, paint, inkjet ink, ultraviolet curable ink, writing instrument ink, applicator ink, stamp ink, paint, cosmetic, and fiber coloring liquid.

6. A writing instrument containing the writing instrument ink according to Claim 5.

7. A solid writing body or a solid cosmetic comprising the microcapsule pigment according to any one of Claims 1 to 3 and an excipient.

8. A resin composition for molding comprising the microcapsule pigment according to any one of Claims 1 to 3 and a molding resin.

9. A molded body formed by molding the resin composition for molding according to Claim 8.

10. A laminate comprising a support and a colored layer containing the microcapsule pigment according to any one of Claims 1 to 3.

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