Aqueous coloring composition, coloring method, pigment dispersion, and method for producing metal pigments

Abstract

To provide a water-based coloring composition or the like having excellent water resistance, glossiness and dispersibility.SOLUTION: There is provided a water-based coloring composition which comprises a metallic pigment, water and an organic solvent, wherein the metallic pigment is surface treated with a first surface treatment agent and a second surface treatment agent, the first surface treatment agent contains a phosphonic acid-based compound represented by the formula (1) or a phosphoric acid-based compound represented by the formula (2), the second surface treatment agent contains a phosphonic acid-based compound represented by the formula (3) or a phosphoric acid-based compound represented by the formula (4), the number of carbons of R1 or R2 in the first surface treatment agent is larger than the number of carbons of R3 or R4 in the second surface treatment agent. (R1)PO(OH)2 (1), (R2O)aPO(OH)3-a (2), (R3)PO(OH)2 (3), (R4O)bPO(OH)3-b (4).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous coloring composition, a coloring method, a pigment dispersion, and a method for producing a metal pigment. [Background technology]

[0002] Traditionally, compositions such as inks and paints containing metallic pigments, including aluminum, have been developed to produce articles with a metallic luster. Furthermore, in recent years, from the perspective of environmental considerations and ease of handling, aqueous compositions with water as the primary solvent have been preferred over non-aqueous compositions with organic solvents as the primary solvent in the development of these compositions.

[0003] For example, Patent Document 1 discloses a base metal pigment for aqueous ink compositions, which has good water resistance and dispersion stability in aqueous media, and in which the base metal pigment is surface-treated with a fluorine-based compound and has a predetermined zeta potential. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2015-140359 [Overview of the project] [Problems that the invention aims to solve]

[0005] As described in Patent Document 1, surface treatment with fluorine-based compounds is expected to improve water resistance and dispersibility. However, metal pigments used in water-based inks require even greater water resistance, dispersibility, and dispersion stability. Naturally, improved gloss is also desired. [Means for solving the problem]

[0006] The aqueous coloring composition of the present invention contains a metal pigment, water, and an organic solvent, and the metal pigment is surface-treated with a first surface treatment agent and a second surface treatment agent. The first surface treatment agent contains a phosphonic acid compound represented by the following formula (1) or a phosphoric acid compound represented by the formula (2), and the second surface treatment agent contains a phosphonic acid compound represented by the following formula (3) or a phosphoric acid compound represented by the formula (4). In the first surface treatment agent, the carbon number of R 1 or R 2 is greater than the carbon number of R 3 or R 4 in the second surface treatment agent. (R 1 )PO(OH)2(1) (In formula (1), R [[ID=I7]] 1 is a hydrocarbon group having 12 or more carbon atoms in which a hydrogen atom may be substituted with a substituent.) (R 2 O) s a PO(OH) 3-a (2) (In formula (2), R 2 are each independently a hydrocarbon group having 12 or more carbon atoms in which a hydrogen atom may be substituted with a substituent, and a is an integer of 1 or 2.) (R 3 )PO(OH)2(3) (In formula (3), R 3 is a hydrocarbon group having a carbon number of 4 or more in which a hydrogen atom may be substituted with a substituent.) (R 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 are each independently a hydrocarbon group having a carbon number of 4 or more in which a hydrogen atom may be substituted with a substituent, and b is an integer of 1 or 2.)

[0007] The coloring method of the present invention includes a step of attaching a coloring composition containing the above aqueous coloring composition to a colored object.

[0008] The pigment dispersion of the present invention contains a metal pigment, water, and an organic solvent, wherein the metal pigment is surface-treated with a first surface treatment agent and a second surface treatment agent, the first surface treatment agent contains a phosphonic acid compound represented by the following formula (1) or a phosphoric acid compound represented by the following formula (2), the second surface treatment agent contains a phosphonic acid compound represented by the following formula (3) or a phosphoric acid compound represented by the following formula (4), and the R in the first surface treatment agent 1 or R 2 The number of carbon atoms is R in the second surface treatment agent described above. 3 or R 4 It has more carbon atoms than [the other number]. (R 1 )PO(OH)2(1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is independently a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents, and a is an integer of 1 or 2. (R 3 )PO(OH)2(3) (In formula (3), R 3 This refers to a hydrocarbon group having four or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is independently a hydrocarbon group having 4 or more carbon atoms, where the hydrogen atoms may be substituted with substituents, and b is an integer of 1 or 2.

[0009] The present invention provides a method for producing a metal pigment, comprising: a first surface treatment step of surface-treating a metal pigment with a first surface treatment agent; and a second surface treatment step of surface-treating the metal pigment surface-treated with the first surface treatment agent with a second surface treatment agent, wherein the first surface treatment agent includes a phosphonic acid compound represented by the following formula (1) or a phosphoric acid compound represented by the following formula (2). The second surface treatment agent described above contains a phosphonic acid compound represented by formula (3) or a phosphoric acid compound represented by formula (4), and the R in the first surface treatment agent described above 1 or R 2 The number of carbon atoms is R in the second surface treatment agent described above. 3 or R 4 It has more carbon atoms than [the other number]. (R 1 )PO(OH)2(1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is independently a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents, and a is an integer of 1 or 2. (R 3 )PO(OH)2(3) (In formula (3), R 3 This refers to a hydrocarbon group having four or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is independently a hydrocarbon group having 4 or more carbon atoms, where the hydrogen atoms may be substituted with substituents, and b is an integer of 1 or 2. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of a coloring apparatus used in the coloring method of this embodiment. [Modes for carrying out the invention]

[0011] The embodiments of the present invention (hereinafter referred to as "these embodiments") will be described in detail below, with reference to the drawings as necessary. However, the present invention is not limited thereto, and various modifications are possible without departing from its essence. In the drawings, the same elements will be denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Moreover, the dimensional ratios in the drawings are not limited to those shown.

[0012] 1. Water-based coloring composition The aqueous coloring composition according to this embodiment (hereinafter also simply referred to as "coloring composition") contains a metal pigment, water, and an organic solvent, wherein the metal pigment is surface-treated with a first surface treatment agent and a second surface treatment agent. The first surface treatment agent contains a phosphonic acid compound represented by formula (1) or a phosphoric acid compound represented by formula (2) below, and the second surface treatment agent contains a phosphonic acid compound represented by formula (3) or a phosphoric acid compound represented by formula (4) below, and the R in the first surface treatment agent 1 or R 2 The number of carbon atoms is R in the second surface treatment agent described above. 3 or R 4 It has more carbon atoms than [the other number]. (R 1 )PO(OH)2(1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is independently a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents, and a is an integer of 1 or 2. (R 3 )PO(OH)2(3) (In formula (3), R 3 This refers to a hydrocarbon group having four or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is independently a hydrocarbon group having 4 or more carbon atoms, where the hydrogen atoms may be substituted with substituents, and b is an integer of 1 or 2.

[0013] Conventionally, in coloring compositions containing metal pigments, coloring compositions containing metal pigments that have been surface-treated with surface treatment agents such as fluorine-based surface treatment agents have been studied with the aim of improving water resistance and other properties. However, there was still room for further investigation into improving water resistance.

[0014] Furthermore, thin, flake-shaped (flat) metallic pigments have been developed to further improve gloss. The larger the surface area of ​​each metallic pigment particle and the thinner the particle, the greater the surface area per unit mass. This makes it easier for the flake-shaped metallic pigment to orient itself so that its plane is more parallel to the plane of the object being colored. The resulting colored object exhibits superior gloss due to the formation of a glossy layer. This orientation is also known as "leafing."

[0015] However, while such flaky metallic pigments improve the gloss of the resulting colored material, they tend to aggregate easily and have poor dispersibility. Furthermore, aggregation can sometimes prevent the desired level of gloss from being achieved.

[0016] Therefore, surface treatment with a surface treatment agent is being considered to suppress aggregation and improve dispersibility. Generally, it is believed that metal pigments with superior water resistance can be obtained by surface treatment with a surface treatment agent having long-chain alkyl groups (hereinafter also called a "long-chain surface treatment agent") rather than a surface treatment agent having short-chain alkyl groups (hereinafter also called a "short-chain surface treatment agent"). However, even with surface treatment using a long-chain surface treatment agent, the water resistance was not sufficient.

[0017] In this regard, the inventors diligently investigated the matter with the aim of further improving water resistance. As a result, it was found that while long-chain alkyl groups can suppress water molecules from approaching the surface of the metal pigment when the surface is treated with a long-chain surface treatment agent, the long-chain surface treatment agent does not easily penetrate into the gaps between the multiple long-chain surface treatment agents bonded to the metal pigment, so the amount of surface treatment by the long-chain surface treatment agent tends to be coarse.

[0018] Therefore, in this embodiment, the metal pigment is surface-treated with a first surface treatment agent corresponding to a long-chain surface treatment agent and a second surface treatment agent corresponding to a short-chain surface treatment agent. This makes it possible to further surface-treat the gaps in the long-chain surface treatment agent with the short-chain surface treatment agent. As a result, water resistance and dispersibility can be further improved. Furthermore, gloss can also be improved.

[0019] In this embodiment, an aqueous composition refers to a composition in which the water content is 20% by mass or more relative to the total solvent components. In this embodiment, water resistance refers to the effect of suppressing gas generation when a metal pigment is brought into contact with water, such as by being incorporated into an aqueous paint or aqueous ink. Furthermore, a coloring composition refers to a composition that can be used as a coloring method itself, such as an inkjet ink or paint composition.

[0020] The following describes in detail the aqueous coloring composition, coloring method, pigment dispersion, and method for producing metal pigments according to this embodiment.

[0021] 1.1. Metallic Pigments The metal pigment in this embodiment is surface-treated with a surface treatment agent. The relationship between the metal pigment and the surface treatment agent in this embodiment is not particularly limited, but for example, by surface modification with the surface treatment agent, the metal particles and the surface treatment agent may be chemically bonded by the reaction between the -OH groups on the surface of the metal pigment and the functional groups of the surface treatment agent.

[0022] The metallic pigment is not particularly limited, but for example, the entire metallic pigment may be made of a metallic material, or it may have a base made of a non-metallic material and a coating made of a metallic material covering the surface of the base. The base made of a non-metallic material may be, for example, a flaky resin, and its entire surface may be covered with a metallic material.

[0023] The content of the metal pigment can be appropriately adjusted depending on the application, such as whether the coloring composition is a pigment dispersion, a paint composition, or an ink composition. As an example for these various applications, the content of the metal pigment is preferably 0.1% to 30% by mass, more preferably 0.3% to 25% by mass, even more preferably 0.5% to 20% by mass, and still more preferably 1.0% to 10% by mass, based on the total amount of the coloring composition. When the content of the metal pigment is within the above range, the composition tends to have excellent dispersibility, gloss, and water resistance.

[0024] 1.1.1. Constituent Materials The metal species constituting the metallic pigment is not particularly limited, but for example, elemental metals and various alloys can be used. Examples of such metallic species include aluminum, silver, gold, platinum, nickel, chromium, zinc, indium, titanium, iron, and copper. Among these, metallic pigments containing base metals are preferred, metallic pigments containing aluminum or aluminum alloys are more preferred, and metallic pigments made of aluminum or aluminum alloys are even more preferred. This results in a tendency for particularly superior gloss among various metallic materials. Furthermore, since aluminum or aluminum alloys have a relatively low specific gravity compared to other metallic materials, they tend to have excellent dispersibility. Moreover, they are superior in suppressing the increase in production costs of colored products manufactured using coloring compositions containing metallic pigments. Note that a single metallic pigment may be used alone, or two or more may be used in combination.

[0025] 1.1.2. Particle Shape The shape of the metallic pigment is not particularly limited, but may be any shape, such as flake-shaped (flat), spherical, spindle-shaped, or needle-shaped. Among these, the metallic pigment is preferably flake-shaped, and more preferably, the metallic pigment is flake-shaped and thin. When the metallic pigment is flake-shaped, the wider surface area of ​​the particles is arranged along the surface of the object to be colored, which tends to further improve the glossiness of the resulting colored product.

[0026] In this embodiment, "scale-like" refers to a shape such as a flat plate or a curved plate, where, when observed from a predetermined angle, for example, the area when viewed from above is larger than the area when observed from an angle perpendicular to the direction of observation.

[0027] The method for measuring the physical properties of metal pigment particles based on observation is not particularly limited, but observation may be performed based on the AFM (atomic force microscopy) method, for example. This method can be used when measuring the average thickness. The atomic force microscope is not particularly limited, and for example, NanoNavi E-Sweep (manufactured by SII Nanotechnology Co., Ltd.) can be used.

[0028] 1.1.3. Volume-average particle diameter Volume average particle size D of metal pigments in coloring compositions 50 The larger the volume average particle size D of the metal pigment in the coloring composition, the better the gloss tends to be, and the smaller the volume average particle size D tends to be, but the preferred range may be defined based on the application of the coloring composition. 50 The volume average particle size D of the metal pigment is preferably 0.10 μm to 15 μm, more preferably 0.20 μm to 12 μm, and even more preferably 0.30 μm to 9.0 μm. 50 When the above range is present, it tends to have excellent gloss, dispersibility, and / or water resistance.

[0029] Furthermore, from a similar perspective, the volume-average particle size D of the metal pigment when the coloring composition is used as an inkjet ink composition or a component thereof. 50 The wavelength is preferably 1.0 μm or less, more preferably 100 nm to 1.0 μm, more preferably 200 nm to 800 nm, and even more preferably 300 nm to 600 nm.

[0030] Furthermore, from the viewpoint of suitably using it as a paint or its component, the volume average particle size D of the metal pigment 50 The particle size is preferably 3.0 μm or more and 15 μm or less, more preferably 5.0 μm or more and 12 μm or less, and even more preferably 7.0 μm or more and 9.0 μm or less.

[0031] Volume average particle diameter D of this embodiment 50 This refers to the median diameter of the volume distribution of a particle dispersion measured using laser diffraction and scattering. When multiple measurement results are expressed as the cumulative abundance ratio for each size, it is the particle size that represents exactly 50% of the median value in the cumulative distribution. If the metal particles are flaky, the volume-average particle diameter shall be determined based on the shape and size of the metal particles when converted to a spherical form.

[0032] 1.1.4. Preparation of Metallic Pigments The method for preparing the metal pigment is not particularly limited, and known methods can be used. For example, a metal film can be formed on one side of a sheet-like substrate using a vapor deposition method, and then the metal film can be peeled off and pulverized from the sheet-like substrate to obtain a flaky metal pigment. This vapor deposition method makes it possible to obtain a flaky metal pigment with less variation in film thickness and high surface flatness, allowing the metallic luster and other properties inherent to the metal pigment to be expressed more effectively. The thickness of the thin film becomes the thickness of the flaky metal pigment. Furthermore, the metal pigment obtained in this way may be classified as needed to adjust its particle size distribution as desired. In addition, ion plating or sputtering may be used instead of the vapor deposition method described above.

[0033] Furthermore, when preparing metallic pigments made of aluminum or aluminum alloys, it is preferable to prepare them by grinding a film formed by vapor deposition, from the viewpoint of more effectively expressing their luster and other properties. This method can also be used when preparing relatively thin metallic pigments.

[0034] As the sheet-like substrate used in the above vapor deposition method, for example, a plastic film such as polyethylene terephthalate (PET) can be used. In addition, a release agent such as silicone oil may be applied to the film-forming surface of the sheet-like substrate in advance to improve release properties, or a release resin layer may be formed. Examples of resins used for the release resin layer include polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, polymethacrylic acid ester, polyacrylamide, cellulose derivatives such as cellulose acetate butyrate, and modified nylon resins.

[0035] The peeling and pulverization of the metal film is performed by applying external force, for example, by irradiating the film with ultrasound in an organic solvent or by stirring it with a homogenizer. The organic solvent used is not particularly limited, but can preferably be alcohols such as methanol, ethanol, propanol, and butanol; hydrocarbon compounds such as n-heptane, n-octane, decane, dodecane, tetradecane, toluene, xylene, decahydronaphthalene, and cyclohexylbenzene; ether compounds such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, bis(2-methoxyethyl) ether, and p-dioxane; and polar organic solvents such as propylene carbonate, γ-butyrolactone, N-methyl-2-pyrrolidone, N,N-dimethylformamide, and acetonitrile. By using such organic solvents, it is possible to prevent unintended oxidation of the metal pigment while reducing variations in size, shape, and properties between individual particles.

[0036] 1.2. Surface treatment agents The metal pigment used in this embodiment is surface-treated with a first surface treatment agent and a second surface treatment agent. The first surface treatment agent in this embodiment contains a phosphonic acid compound represented by formula (1) or a phosphoric acid compound represented by formula (2) below, and the second surface treatment agent contains a phosphonic acid compound represented by formula (3) or a phosphoric acid compound represented by formula (4) below, and the R in the first surface treatment agent 1 or R 2 The number of carbon atoms in the second surface treatment agent is R 3 or R 4 It has more carbon atoms than [the other number]. (R 1 )PO(OH)2(1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 2 O) a PO(OH) 3-a (2) (In formula (2), R 2Each of these is independently a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents, and a is an integer of 1 or 2. (R 3 )PO(OH)2(3) (In formula (3), R 3 This refers to a hydrocarbon group having four or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is independently a hydrocarbon group having 4 or more carbon atoms, where the hydrogen atoms may be substituted with substituents, and b is an integer of 1 or 2.

[0037] The compounds represented by the above general formulas (1) and (3) (substituted or unsubstituted alkyl phosphonic acids) are compounds in which the hydrogen atoms of the phosphonic acid are substituted with (R1-) and (R3-) groups. Because such compounds have less steric hindrance due to the alkyl group, they are easily positioned in areas of the metal particle surface that have not been surface-treated with long-chain surface treatment agents, and can improve the dispersion stability and gloss of the metal pigment.

[0038] The compounds represented by the above general formulas (2) and (4) are compounds in which one or two of the three hydroxyl groups of phosphoric acid are esterified with a substituted or unsubstituted alkyl group.

[0039] The compounds represented by general formulas (2) and (4) are diesters (di-isomers) of substituted or unsubstituted alkyl groups when a is 1, and monoesters (mono-isomers) of substituted or unsubstituted alkyl groups when a is 2. When a is 1 (di-isomer), the compounds represented by general formulas (2) and (4) have two substituted or unsubstituted alkyl groups, which increases the steric hindrance that prevents water molecules from approaching the surface of the metal particles, thus tending to make the metal pigments more water-resistant. Hereafter, "monoester" may be referred to as "mono-isomer" and "diester" as "di-isomer".

[0040] In the above formulas (1) and (2), R 1 and R 2 are each a hydrocarbon group having 12 or more carbon atoms in which a hydrogen atom may be substituted with a substituent. In the above formulas (3) and (4), R 3 and R 4 are each a hydrocarbon group having 4 or more carbon atoms in which a hydrogen atom may be substituted with a substituent. The hydrocarbon group may be any of a branched-chain type, a straight-chain type, or a cyclic type, and may contain a saturated bond or an unsaturated bond. The hydrocarbon group having 12 or more carbon atoms is a hydrocarbon group having a skeleton in which 12 or more carbon atoms are continuously bonded. Also, R 1 、 R 2 、R 3 、and R 4 do not include the carbon atoms of the substituent in their carbon numbers.

[0041] R 1 、R 2 、R 3 、or R 4 There is no particular limitation on the type of substituent in, and examples thereof include a halogen atom, a carboxyl group, a hydroxyl group, an amino group, an oxyalkylene group, etc. More specifically, R 1 、R 2 、R 3 、or R 4 may be a perfluoro group in which a hydrogen atom of the hydrocarbon group described later is substituted with a fluorine atom. R 1 、R 2 、R 3 、or R 4 Each may have some of the hydrogen atoms of the hydrocarbon group substituted by such a substituent, but R 1 、R 2 、R 3 、or R 4 The number of substituents each has may be 1 or less, or it may have no substituent. When having a substituent, R 1 、R 2 、R 3 、or R 4The position of the atom is more preferable, as it tends to result in better dispersion stability of the metal pigment, when it is bonded to the carbon atom furthest from P or O.

[0042] The oxyalkylene group has one or more alkylene oxide units, and may have two or more. In particular, it may have a structure in which multiple alkylene oxide units are repeated. The number of repeating alkylene oxide units is preferably 10 or less, more preferably 4 or less. The lower limit is 1 or more, preferably 2 or more, and more preferably 3 or more. The number of alkylene carbon atoms in the alkylene oxide unit is preferably 1 or more and 4 or less.

[0043] Also, R 1 , R 2 , R 3 , or R 4 The hydrocarbon group may be a saturated hydrocarbon group that does not have a double bond or a triple bond between carbon atoms, or it may be an unsaturated hydrocarbon group that has a double bond or a triple bond between carbon atoms. Furthermore, the hydrocarbon group may be an aromatic hydrocarbon group whose carbon skeleton has an aromatic ring structure, or it may be a chain-like or cyclic aliphatic hydrocarbon group, etc. Among these, R 1 , R 2 , R 3 , or R 4 The aliphatic hydrocarbon group is preferably a chain-like aliphatic hydrocarbon group. The chain-like aliphatic hydrocarbon group includes branched-chain and linear types, but is preferably linear.

[0044] 1.2.1. First surface treatment agent The first surface treatment agent includes a phosphonic acid compound represented by formula (1) or a phosphoric acid compound represented by formula (2). From the viewpoint of improving the water resistance of the metal pigment, it is preferable to use a phosphonic acid compound represented by formula (1) as the first surface treatment agent.

[0045] In formula (1), the hydrocarbon group R 1In this, one of the carbon atoms is directly bonded to the phosphorus atom of formula (1), and the oxygen atom is directly bonded to the phosphorus atom of P, but R 1 In this case, the atom directly bonded to the phosphorus atom is preferably R 1 It is the carbon atom at the end of the molecular chain. Similarly, in formula (2), the hydrocarbon group R 2 If any of the carbon atoms in is (R) of formula (2) 2 It is directly bonded to the oxygen atom in O), and that oxygen atom is directly bonded to the phosphorus atom in P, but R 2 The atom directly bonded to the oxygen atom in is preferably R 2 It is the carbon atom at the end of the molecular chain.

[0046] In equation (1) or equation (2), R 1 or R 2 The number of carbon atoms in each atom is 12 or more, preferably 12 to 32, more preferably 15 to 30, even more preferably 16 to 22, and even more preferably 16 to 20. This improves the dispersion stability and water resistance of the coloring composition.

[0047] In equation (1) or equation (2), R 1 or R 2 Specific examples include, but are not limited to, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, n-docosyl group, n-tetracosyl group, etc. From the viewpoint of excellent water resistance, dispersibility, and gloss, n-dodecyl group, n-octadecyl group, or n-docosyl group are preferred.

[0048] Specific examples of phosphonic acid compounds represented by formula (1) are not particularly limited, but include, for example, dodecylphosphonic acid, tridecylphosphonic acid, tetradecylphosphonic acid, pentadecylphosphonic acid, hexadecylphosphonic acid, heptadecylphosphonic acid, octadecylphosphonic acid, nonadecylphosphonic acid, eicosylphosphonic acid, henicosylphosphonic acid, and docosylphosphonic acid. Furthermore, from the viewpoint of excellent water resistance, dispersibility, and gloss, it is preferable to use docosylphosphonic acid, octadecylphosphonic acid, and / or dodecylphosphonic acid as the phosphonic acid compound represented by formula (1), more preferable to use octadecylphosphonic acid or dodecylphosphonic acid, and even more preferable to use octadecylphosphonic acid.

[0049] Specific examples of phosphate compounds represented by formula (2) are not particularly limited, but include, for example, dodecyl phosphate, tridecyl phosphate, tetradecyl phosphate, pentadecyl phosphate, hexadecyl phosphate, heptadecyl phosphate, octadecyl phosphate, nonadecyl phosphate, eicosyl phosphate, didecyl phosphate, diundecyl phosphate, didodecyl phosphate, ditridecyl phosphate, ditetradecyl phosphate, dipentadecyl phosphate, dihexadecyl phosphate, diheptadecyl phosphate, dioctadecyl phosphate, dinonadecyl phosphate, and diicosyl phosphate. Furthermore, from the viewpoint of excellent water resistance, dispersibility, and gloss, octadecyl phosphate is preferred as the phosphate compound represented by formula (2).

[0050] The content of the first surface treatment agent is preferably 10% to 50% by mass, more preferably 12% to 48% by mass, even more preferably 15% to 45% by mass, and still more preferably 20% to 40% by mass, based on the total amount of metal pigments contained in the coloring composition. When the content of the first surface treatment agent is 10% by mass or more, the water resistance tends to be excellent, and when it is 50% by mass or less, the dispersibility and gloss tend to be excellent.

[0051] Furthermore, the content of the first surface treatment agent is preferably 0.05% by mass or more and 10.0% by mass or less, more preferably 0.10% by mass or more and 2.5% by mass or less, even more preferably 0.15% by mass or more and 2.0% by mass or less, and even more preferably 0.20% by mass or more and 1.0% by mass or less, based on the total amount of the coloring composition. When the content of the first surface treatment agent is 0.05% by mass or more, the water resistance tends to be excellent, and when it is 3.0% by mass or less, the dispersibility and gloss tend to be excellent.

[0052] 1.2.2. Second surface treatment agent The second surface treatment agent includes a phosphonic acid compound represented by formula (3) or a phosphoric acid compound represented by formula (4).

[0053] R in the first surface treatment agent 1 or R 2 The number of carbon atoms and R in the second surface treatment agent 3 or R 4 The difference in the number of carbon atoms is preferably between 4 and 14. 1 Or R 2 and R 3 Or R 4 As the difference in carbon number between the two is within the above range, water resistance, gloss, and dispersibility tend to be further improved. From a similar perspective, R 1 Or R 2 and R 3 Or R 4 The difference in the number of carbon atoms is more preferably 5 to 12, and even more preferably 6 to 10.

[0054] In formula (3), the hydrocarbon group R 3 In this, one of the carbon atoms is directly bonded to the phosphorus atom of formula (3), and the oxygen atom is directly bonded to the phosphorus atom of P, but R 3 In this case, the atom directly bonded to the phosphorus atom is preferably R 3 It is the carbon atom at the end of the molecular chain. Similarly, in formula (4), the hydrocarbon group R 4If any of the carbon atoms in is (R) of formula (4) 4 It is directly bonded to the oxygen atom in O), and that oxygen atom is directly bonded to the phosphorus atom in P, but R 4 The atom directly bonded to the oxygen atom in is preferably R 4 It is the carbon atom at the end of the molecular chain.

[0055] In equation (3) or equation (4), R 3 or R 4 The number of carbon atoms in each element is 4 or more, and may be between 4 and 30. From the viewpoint of excellent water resistance, dispersibility, and gloss, R 3 or R 4 The number of carbon atoms is preferably 4 to 18, more preferably 4 to 12, even more preferably 4 to 11, and even more preferably 4 to 8.

[0056] In equation (3) or equation (4), R 3 or R 4 Specific examples include, but are not limited to, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, n-tetracosyl group, etc. From the viewpoint of excellent water resistance, dispersibility, and gloss, it is preferable to have an n-butyl group, n-octyl group, n-dodecyl group, or n-octadecyl group, and more preferably an n-butyl group, n-octyl group, or n-dodecyl group.

[0057] Specific examples of phosphonic acid compounds represented by formula (3) are not particularly limited, but include, for example, butylphosphonic acid, pentylphosphonic acid, hexylphosphonic acid, octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, undecylphosphonic acid, dodecylphosphonic acid, tridecylphosphonic acid, tetradecylphosphonic acid, pentadecylphosphonic acid, hexadecylphosphonic acid, heptadecylphosphonic acid, octadecylphosphonic acid, nonadecylphosphonic acid, eicosylphosphonic acid, henicosylphosphonic acid, docosylphosphonic acid, etc. Furthermore, from the viewpoint of excellent water resistance, dispersibility, and gloss, it is preferable to use butylphosphonic acid, octylphosphonic acid, dodecylphosphonic acid, or octadecylphosphonic acid as the phosphonic acid compound represented by formula (3), and it is more preferable to use butylphosphonic acid, octylphosphonic acid, or dodecylphosphonic acid.

[0058] Specific examples of phosphate compounds represented by formula (4) are not particularly limited, but include butyl phosphate, pentyl phosphate, hexyl phosphate, octyl phosphate, nonyl phosphate, decyl phosphate, undecyl phosphate, dodecyl phosphate, tridecyl phosphate, tetradecyl phosphate, pentadecyl phosphate, hexadecyl phosphate, heptadecyl phosphate, octadecyl phosphate, nonadecyl phosphate, eicosyl phosphate, didecyl phosphate, diundecyl phosphate, didodecyl phosphate, ditridecyl phosphate, ditetradecyl phosphate, dipentadecyl phosphate, dihexadecyl phosphate, diheptadecyl phosphate, dioctadecyl phosphate, dinonadecyl phosphate, and diicosyl phosphate. Furthermore, from the viewpoint of excellent water resistance, dispersibility, and gloss, it is preferable to use butyl phosphate, octyl phosphate, or dodecyl phosphate as the phosphate compound represented by formula (4).

[0059] The content of the second surface treatment agent is preferably 10% to 50% by mass, more preferably 12% to 48% by mass, even more preferably 15% to 45% by mass, and still more preferably 20% to 40% by mass, based on the total amount of metal pigments contained in the coloring composition. When the content of the second surface treatment agent is 10% by mass or more, the water resistance tends to be excellent, and when it is 50% by mass or less, the dispersibility and gloss tend to be excellent.

[0060] Furthermore, the content of the second surface treatment agent is preferably 0.05% by mass or more and 10.0% by mass or less, more preferably 0.10% by mass or more and 2.5% by mass or less, even more preferably 0.15% by mass or more and 2.0% by mass or less, and even more preferably 0.20% by mass or more and 1.0% by mass or less, based on the total amount of the coloring composition. When the content of the second surface treatment agent is 0.05% by mass or more, the water resistance tends to be excellent, and when it is 3.0% by mass or less, the dispersibility and gloss tend to be excellent.

[0061] The coloring composition according to this embodiment may contain surface treatment agents other than the first and second surface treatment agents described above, as long as the effects of the present invention are not impaired. Examples of such surface treatment agents include fluorine-based compounds. Preferably, fluorine-based compounds include compounds containing fluorine and one or more elements selected from phosphorus, sulfur, and nitrogen as constituent elements. Specifically, examples include fluorine-based phosphonic acids, fluorine-based carboxylic acids, fluorine-based sulfonic acids, and salts thereof.

[0062] 1.3.Water The coloring composition of this embodiment is an aqueous coloring composition containing water. The aqueous coloring composition is a coloring composition that contains at least water as the main solvent component of the coloring composition.

[0063] The water content can be adjusted as appropriate depending on the application, such as whether the coloring composition is an inkjet ink or a pigment dispersion. As an example for these various applications, the water content is preferably 30% to 98% by mass, more preferably 40% to 95% by mass, even more preferably 50% to 90% by mass, and even more preferably 60% to 80% by mass, based on the total amount of the coloring composition. When the water content is within the above range, the composition tends to have excellent water resistance, gloss, and dispersibility.

[0064] 1.4. Organic Solvents The coloring composition of this embodiment contains a water-soluble organic solvent. Such organic solvents are not particularly limited and may include, for example, alcohols, hydrocarbon compounds, ether compounds, ketones, esters, propylene carbonate, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, cyclohexanone, acetonitrile, etc.

[0065] Among these, it is preferable to use alcohols as the organic solvent. By using alcohols, the water resistance, dispersibility, and gloss of the resulting composition tend to be further improved as a synergistic effect with the surface treatment agent mentioned above. Note that one type of organic solvent may be used alone, or two or more types may be used in combination.

[0066] Specifically, examples of organic solvents for alcohols include monoalcohol compounds such as methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, 1-butanol (n-butanol), 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, 3-methoxy-3-methylbutanol, and tert-pentanol; 1,2-hexanediol, hexylene glycol, propylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-propyl alcohol. Examples include glycol compounds such as ropanediol, 1,2-butanediol, 1,2-pentanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol; aromatic alcohol compounds such as 2-phenoxyethanol, phenoxydiglycol, (methoxyphenoxy)ethanol, methylphenoxyethanol, bis(β-hydroxyethyl)hydroquinone ether, nonylphenol, phenol, cresol, resorcinol, catechol, hydroquinone, naphthol, and furfuryl alcohol; and polyhydric alcohol compounds such as glycerin.

[0067] Among these, the organic solvent included in the coloring composition preferably contains glycol compounds and / or aromatic alcohol compounds, and more preferably glycol compounds. By using such organic solvents, the dispersibility and water resistance of the resulting composition, as well as the glossiness of the colored product, tend to be further improved as a synergistic effect with the surface treatment agent mentioned above. Furthermore, from a similar viewpoint, it is more preferable to include 1,2-hexanediol and 2-phenoxyethanol.

[0068] In addition to the above, esters, alkylene glycol ethers, cyclic esters, alkoxyalkylamides, and other organic solvents may also be included.

[0069] Esters include glycol monoacetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, methoxybutyl acetate, ethylene glycol diacetate, and diethylene glycol. Examples of glycol diesters include propyl diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, diethylene glycol acetate butyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, dipropylene glycol acetate butyrate, and dipropylene glycol acetate propionate.

[0070] The alkylene glycol ethers can be any monoether or diether of alkylene glycol, with alkyl ethers being preferred. Specific examples include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monobutyl ether. Examples include alkylene glycol monoalkyl ethers such as ethyl ether, and alkylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol methyl butyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and tripropylene glycol dimethyl ether.

[0071] Furthermore, of the alkylene glycols mentioned above, diethers tend to dissolve or swell the resin in the ink composition more easily than monoethers, and are therefore preferred in that they can further improve friction fastness.

[0072] Examples of cyclic esters include cyclic esters (lactones) such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, β-butyrolactone, β-valerolactone, γ-valerolactone, β-hexanolactone, γ-hexanolactone, δ-hexanolactone, β-heptanolactone, γ-heptanolactone, δ-heptanolactone, ε-heptanolactone, γ-octanolactone, δ-octanolactone, ε-octanolactone, δ-nonalactone, ε-nonalactone, and ε-decanolactone, as well as compounds in which the hydrogen atoms of the methylene group adjacent to the carbonyl group are substituted with alkyl groups having 1 to 4 carbon atoms.

[0073] Examples of alkoxyalkylamides include 3-methoxy-N,N-dimethylpropionamide, 3-methoxy-N,N-diethylpropionamide, 3-methoxy-N,N-methylethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-diethylpropionamide, 3-ethoxy-N,N-methylethylpropionamide, 3-n-butoxy-N,N-dimethylpropionamide, 3-n-butoxy-N,N-diethylpropionamide, 3-n-butoxy-N,N-methylethylpropionamide, 3-n-propoxy-N, Examples include N-dimethylpropionamide, 3-n-propoxy-N,N-diethylpropionamide, 3-n-propoxy-N,N-methylethylpropionamide, 3-iso-propoxy-N,N-dimethylpropionamide, 3-iso-propoxy-N,N-diethylpropionamide, 3-iso-propoxy-N,N-methylethylpropionamide, 3-tert-butoxy-N,N-dimethylpropionamide, 3-tert-butoxy-N,N-diethylpropionamide, 3-tert-butoxy-N,N-methylethylpropionamide, etc.

[0074] Examples of cyclic amides include lactams, such as pyrrolidones including 2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-propyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone. These are preferred in that they promote resin film formation, with 2-pyrrolidone being particularly preferred.

[0075] The content of the organic solvent can be adjusted as appropriate depending on the intended use of the coloring composition. As an example for various uses, the content of the organic solvent is preferably 10% to 60% by mass, more preferably 15% to 55% by mass, even more preferably 20% to 50% by mass, even more preferably 25% to 45% by mass, and particularly preferably 30% to 40% by mass, based on the total amount of the coloring composition. When the content of the organic solvent is within the above range, the composition tends to have excellent water resistance, gloss, and dispersibility.

[0076] 1.5. Other ingredients The coloring composition of this embodiment may contain other components. Examples of other components include dispersants, resins, and other ingredients.

[0077] 1.6.Applications The use of the coloring composition of this embodiment is not particularly limited, but it is preferable to use it as a paint composition or ink composition because it is suitable for use in such applications. The ink composition may be an inkjet ink composition. The coloring composition can also be used as a raw material for a pigment dispersion.

[0078] 2. Pigment dispersion In this embodiment, the pigment dispersion may be a pigment dispersion used in the preparation of a paint composition, or a pigment dispersion used in the preparation of an ink composition.

[0079] The pigment dispersion of this embodiment is a pigment dispersion containing a metal pigment, water, and an organic solvent, wherein the metal pigment is surface-treated with a first surface treatment agent and a second surface treatment agent, the first surface treatment agent containing a phosphonic acid compound represented by formula (1) or a phosphoric acid compound represented by formula (2), the second surface treatment agent containing a phosphonic acid compound represented by formula (3) or a phosphoric acid compound represented by formula (4), and the R in the first surface treatment agent 1 or R 2 The number of carbon atoms is R in the second surface treatment agent described above.3 or R 4 It has more carbon atoms than [the other number]. (R 1 )PO(OH)2(1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is independently a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents, and a is an integer of 1 or 2. (R 3 )PO(OH)2(3) (In formula (3), R 3 This refers to a hydrocarbon group having four or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is independently a hydrocarbon group having 4 or more carbon atoms, where the hydrogen atoms may be substituted with substituents, and b is an integer of 1 or 2.

[0080] The metal pigment, water, organic solvent contained in the pigment dispersion, and the surface treatment agent for surface-treating the metal pigment can be used according to the above-mentioned materials and compounds, in the amounts and methods of use described above.

[0081] The pigment dispersion of this embodiment may contain components other than those described above. Examples of such components include other components exemplified in the coloring composition, and these can be added as appropriate and as needed.

[0082] 3. Method for manufacturing metal pigments The method for producing a metal pigment according to this embodiment comprises a first surface treatment step of surface-treating the metal pigment with a first surface treatment agent, and a second surface treatment step of surface-treating the metal pigment surface-treated with the first surface treatment agent with a second surface treatment agent, wherein the first surface treatment agent contains a phosphonic acid compound represented by the following formula (1) or a phosphoric acid compound represented by the following formula (2), and the second surface treatment agent contains a phosphonic acid compound represented by the following formula (3) or a phosphoric acid compound represented by the following formula (4). (R 1 )PO(OH)2(1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is independently a hydrocarbon group having 12 or more carbon atoms, where hydrogen atoms may be substituted with substituents, and a is an integer of 1 or 2. (R 3 )PO(OH)2(3) (In formula (3), R 3 This refers to a hydrocarbon group having four or more carbon atoms, where hydrogen atoms may be substituted with substituents. (R 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is independently a hydrocarbon group having 4 or more carbon atoms, where the hydrogen atoms may be substituted with substituents, and b is an integer of 1 or 2.

[0083] The method for producing the metal pigment in this embodiment involves performing a first surface treatment step, followed by a second surface treatment step using a surface treatment agent with a shorter alkyl chain (i.e., fewer carbon atoms in the alkyl chain) than the first surface treatment agent. This reduces the area of ​​the metal surface where the surface treatment agent is not adsorbed, thereby improving the water resistance of the metal pigment. As a result, it is presumed that the gloss and dispersibility of the coloring composition containing the metal pigment will also improve, but the factors are not limited to this.

[0084] When surface-treating metal pigments, known surface treatment methods may be used. For example, a surface treatment agent can be added to a dispersion in which metal pigments are dispersed in an organic solvent, and the surface treatment agent can be bonded to the surface of the metal pigment by irradiating it with ultrasound. In this case, the amount of surface treatment agent to be added should be the amount described above as appropriate.

[0085] Furthermore, while the above-mentioned surface treatment agent may be applied directly to the surface of the metal pigment, it may also be applied to a metal pigment that has been pre-treated with an acid or base. This allows for more reliable chemical modification of the metal pigment surface by the surface treatment agent, and enables the effects of the present invention described above to be expressed more effectively. In addition, the oxide film on the metal pigment can be removed by treatment with an acid or base, thereby improving the glossiness.

[0086] The acid used for pretreatment is not particularly limited, but examples include hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, boric acid, acetic acid, carbonic acid, formic acid, benzoic acid, chlorous acid, hypochlorous acid, sulfurous acid, hyposulfurous acid, nitrite, hyponitrite, phosphorous acid, and hypophosphorous acid. On the other hand, the base used for pretreatment is not particularly limited, but examples include sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0087] 3.1. First surface treatment process In the first surface treatment step, it is preferable to perform the surface treatment in a solvent-based medium. Performing the first surface treatment step in a solvent-based medium tends to improve water resistance, gloss, and dispersibility. In this embodiment, the solvent-based medium refers to a medium containing an organic solvent used when performing surface treatment on metal pigments. One type of solvent-based medium may be used alone, or two or more types may be used in combination.

[0088] Such solvent-based media are not particularly limited, but examples include diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, and ethylene glycol monobutyl ether. Among these, surface treatment in diethylene glycol diethyl ether is preferable from the viewpoint of improving water resistance, gloss, and dispersibility.

[0089] 3.2. Second surface treatment process In the second surface treatment step, it is preferable to perform the surface treatment in an aqueous medium. Performing the second surface treatment step in an aqueous medium tends to facilitate the adsorption of the second surface treatment agent onto the surface of the metal pigment, thereby improving water resistance.

[0090] The aqueous medium is not particularly limited, but for example, the above-mentioned water-soluble organic solvent, water, etc., can be used, and it is preferable to use something similar to the ink water, which has the same composition as the above-mentioned aqueous coloring composition except that it does not contain metal pigments.

[0091] In the method for producing metal pigments, the metal pigments and surface treatment agents used can be the materials and compounds described above.

[0092] 4. Coloring method The coloring method of this embodiment may be printing by an inkjet method that includes a step of applying the above-mentioned coloring composition to the object to be colored, or it may be painting in which the paint is applied to the object to be colored using a spray, brush, bar coater, etc.

[0093] When the coloring composition of this embodiment is used as a paint composition, methods for applying the paint composition to the object to be colored include, for example, brush application, spraying, dipping, flow coating, and spin coating. A heat drying step may also be included after the application step. In the heat drying step, the object to be colored to which the coloring composition has been applied is heated and dried.

[0094] Furthermore, when a coloring composition is used as a raw material for an ink composition, one method for applying the ink composition to the object to be colored is, for example, an inkjet method in which the ink composition is ejected from an inkjet head. More specifically, a pressure generating means provided in the inkjet head is driven to eject the ink filled in the pressure generating chamber of the inkjet head from a nozzle. Examples of inkjet heads used in the application process include line heads that perform coloring in a line manner and serial heads that perform coloring in a serial manner.

[0095] 5.Coloring device The following describes in detail an example of a coloring apparatus that can be used for inkjet coloring when the coloring composition of this embodiment is used in an inkjet ink composition.

[0096] Such an inkjet coloring apparatus comprises an inkjet head having nozzles for ejecting inkjet ink onto an object to be colored, and a transport means for transporting the object to be colored. The inkjet head includes a pressure chamber to which ink is supplied and nozzles for ejecting the ink. The transport means consists of transport rollers and a transport belt provided within the coloring apparatus.

[0097] An example of a coloring apparatus according to this embodiment will be described below with reference to Figure 1. In Figure 1, the XYZ coordinate system is such that the X direction represents the length direction of the object to be colored, the Y direction represents the width direction of the object to be colored in the transport path within the coloring apparatus, and the Z direction represents the height direction of the apparatus.

[0098] As an example, the coloring device 10 is a line-type inkjet printer capable of high-speed and high-density printing. The coloring device 10 includes a feeding unit 12 for storing the object to be colored P, such as paper, a transport unit 14, a belt transport unit 16, a coloring unit 18, an Fd (face down) discharge unit 20 as an "discharge unit", an Fd (face down) placement unit 22 as a "placement unit", an inversion path unit 24 as an "inversion transport mechanism", a Fu (face up) discharge unit 26, and a Fu (face up) placement unit 28.

[0099] The feeding unit 12 is located at the bottom of the coloring device 10. The feeding unit 12 includes a feeding tray 30 for storing the objects to be colored P, and a feeding roller 32 for sending the objects to be colored P stored in the feeding tray 30 to the transport path 11.

[0100] The objects to be colored P, stored in the feeding tray 30, are fed along the transport path 11 to the transport unit 14 by the feeding roller 32. The transport unit 14 is equipped with a transport drive roller 34 and a transport driven roller 36. The transport drive roller 34 is rotationally driven by a drive source (not shown). In the transport unit 14, the objects to be colored P are nipped between the transport drive roller 34 and the transport driven roller 36 and transported to the belt transport unit 16 located downstream of the transport path 11.

[0101] The belt conveying unit 16 includes a first roller 38 located upstream in the conveying path 11, a second roller 40 located downstream, an endless belt 42 rotatably mounted on the first roller 38 and the second roller 40, and a support 44 that supports the upper section 42a of the endless belt 42 between the first roller 38 and the second roller 40.

[0102] The endless belt 42 is driven by a first roller 38 or a second roller 40, driven by a drive source (not shown), to move in the upper section 42a from the +X direction to the -X direction. As a result, the object to be colored P, conveyed from the conveying section 14, is further conveyed downstream of the conveying path 11 in the belt conveying section 16.

[0103] The coloring unit 18 comprises a line-type inkjet head 48 and a head holder 46 that holds the inkjet head 48. The coloring unit 18 may also be a serial-type unit in which the inkjet head is mounted on a carriage that reciprocates in the Y-axis direction. The inkjet head 48 is positioned to face the upper section 42a of the endless belt 42 supported by the support 44. When the object to be colored P is conveyed in the upper section 42a of the endless belt 42, the inkjet head 48 ejects ink toward the object to be colored P and performs coloring. The object to be colored P is conveyed downstream of the conveying path 11 by the belt conveying unit 16 while coloring is being performed.

[0104] A "line-type inkjet head" is a head used in a coloring device that forms an image by fixing one of the head or the coloring object P and moving the other. The nozzle area formed in a direction intersecting the transport direction of the object to be colored P is provided so as to be able to cover the entire intersecting direction of the object to be colored P. However, the nozzle area in the intersecting direction of the line head does not necessarily have to be able to cover the entire intersecting direction of all the coloring objects P that the coloring device supports.

[0105] Furthermore, a first branching section 50 is provided downstream of the conveying path 11 of the belt conveying section 16. The first branching section 50 is configured to switch between a conveying path 11 that conveys the object to be colored P to the Fd discharge section 20 or the Fu discharge section 26, and a reversal path 52 of a reversal path section 24 that reverses the colored surface of the object to be colored P and conveys the object to be colored P back to the coloring section 18. When the object to be colored P is switched to the reversal path 52 by the first branching section 50 and conveyed, the colored surface is reversed during the conveying process in the reversal path 52, and the object is conveyed back to the coloring section 18 so that the surface opposite to the initial colored surface faces the inkjet head 48.

[0106] A second branch section 54 is provided downstream of the first branch section 50 along the transport path 11. The second branch section 54 is configured to switch the transport direction of the object to be colored P so as to transport the object to be colored P toward the Fd discharge section 20 or toward the Fu discharge section 26.

[0107] At the second branching section 54, the object to be colored P is transported toward the Fd discharge section 20, discharged from the Fd discharge section 20, and placed on the Fd placement section 22. At this time, the colored surface of the object to be colored P is placed facing the Fd placement section 22. Also, at the second branching section 54, the object to be colored P is transported toward the Fu discharge section 26, discharged from the Fu discharge section 26, and placed on the Fu placement section 28. At this time, the colored surface of the object to be colored P is placed facing away from the Fu placement section 28.

[0108] Although the above describes an example using a line-type inkjet head, the coloring apparatus according to this embodiment may also be a printer using a serial-type inkjet head (serial printer). In a serial printer, printing is performed by moving the inkjet head in a direction intersecting the transport direction while transporting the object to be colored in the transport direction.

[0109] 6. Colored object The material to be colored in this embodiment is not particularly limited, but for example, absorbent or non-absorbent materials may be used depending on the application.

[0110] The absorbent colored material is not particularly limited, but examples include plain paper such as electrophotographic paper with high ink permeability to inkjet inks, inkjet paper (inkjet-specific paper equipped with an ink-absorbing layer composed of silica particles or alumina particles, or an ink-absorbing layer composed of hydrophilic polymers such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP)), and art paper, coated paper, and cast paper used in general offset printing, which have relatively low ink permeability.

[0111] Non-absorbable colored materials are not particularly limited, but examples include films and plates of plastics such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, and polyurethane; plates of metals such as iron, silver, copper, and aluminum; or metal plates or plastic films made by vapor deposition of these various metals, plates of alloys such as stainless steel and brass; and colored materials obtained by bonding (coating) films of plastics such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, and polyurethane to a paper substrate. [Examples]

[0112] The present invention will be described more specifically below using examples and comparative examples. The present invention is not limited in any way by the following examples.

[0113] 1. Preparation of coloring composition A release layer was formed on a 20 μm PET substrate by coating it with a release resin solubilized with acetone using a roll coater. The PET substrate with the release layer was transported to an aluminum vacuum deposition machine at a speed of 5 m / s, and an aluminum layer with a thickness of 15 nm was formed under reduced pressure. The prepared aluminum / release resin / PET substrate was immersed in a tetrahydrofuran tank and irradiated with 40 kHz ultrasound to peel the aluminum pigment from the PET substrate, obtaining an aluminum pigment peeling solution. Next, after removing the tetrahydrofuran with a centrifuge, an appropriate amount of diethylene glycol diethyl ether was added to obtain an aluminum particle suspension with an aluminum concentration of 5% by mass.

[0114] An aluminum pigment suspension (5%, diethylene glycol diethyl ether) was pulverized using a circulating high-power ultrasonic grinder (20 kHz) until the desired average particle size was achieved, thereby obtaining an aluminum pigment suspension with an inkjet-ready particle size of 0.5 μm or less.

[0115] After the aforementioned grinding process, the aluminum pigment was dispersed down to primary particles by heat treatment at 55°C for 1 hour under 40 kHz ultrasonic irradiation to break down agglomeration. The first surface treatment agent was added to the aluminum pigment suspension dispersed down to primary particles, and the suspension was heat-treated at 55°C for 3 hours under 28 kHz ultrasonic irradiation.

[0116] The obtained aluminum dispersion was centrifuged, and the solvent in the aluminum dispersion was replaced with the ink water described in Tables 1-3 to prepare the ink composition. Then, the second surface treatment agent was added and the mixture was heat-treated in the same manner to obtain an ink composition containing a surface-treated metal pigment. Analysis of the solvent removed from the dispersion of the surface-treated aluminum pigment after surface treatment revealed that no surface treatment agent was present in any of the examples. Therefore, it is presumed that the surface treatment agents in each example in the table are adhering to the metal particles contained in the composition.

[0117] In the table, the values ​​for each component shown in each example represent mass percentages of the total amount of the coloring composition unless otherwise specified. Furthermore, the values ​​for metal pigments in the table represent mass percentages of the solid content. In the table, the surface treatment agent with the longest hydrocarbon group in each example is designated as the first surface treatment agent, and the surface treatment agent with the next longest hydrocarbon group is designated as the second surface treatment agent.

[0118] [Table 1]

[0119] [Table 2]

[0120] [Table 3]

[0121] The abbreviations and product ingredient details used in Tables 1-3 are as follows.

[0122] <Surface treatment agent> Docosil (C 22 H 45 )Phosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) • Octadecyl (C 18 H 37 )Phosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) • Octadecyl (C 18 H 37 ) Phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) Dodecyl (C 12 H 25 )Phosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) Dodecyl (C 12 H 25 ) Phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) Octyl (C8H) 17 )Phosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) Octyl (C8H) 17 ) Phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) • Butyl (C4H9) phosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) Butyl (C4H9) phosphoric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) • Ethyl (C2H5) phosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) • Ethyl (C2H5) phosphoric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) • FHP (Perfluorohexylphosphonic Acid, manufactured by Unimatec) <Organic solvents> · 1,2-Hexanediol(C6H 14 O2) ·2-PhenoxyEthanol(C8H 10 O2)

[0123] 2. Evaluation Method 2.1. Particle size, etc. Volume average particle size (D) of metallic pigments 50 The particle size distribution was measured using a Microtrac MT-3300 (Microtrac-Bell, a laser diffraction / scattering particle size distribution analyzer). All metal pigments were found to be flaky.

[0124] 2.2. Water resistance Ten cc of the coloring composition obtained as described above was sealed in an aluminum pack. The aluminum pack was stored at a constant temperature of 70°C for six days. The amount of gas generated per unit mass of the coloring composition was determined before sealing it in the aluminum pack and after sealing it and storing it under the above conditions, and the water resistance was evaluated according to the following evaluation criteria. The results of the water resistance evaluation are shown in Tables 1 to 3. (Evaluation Criteria) A: Gas generation amount is less than 0.1 ml / g B: Gas generation amount is 0.1 ml / g or more and less than 0.15 ml / g C: Gas generation amount is 0.15 ml / g or more and less than 0.19 ml / g D: Gas generation amount is 0.19 ml / g or more and less than 1.0 ml / g E: Gas generation amount is 1.0 ml / g or more

[0125] 2.3. Glossiness Using a modified inkjet printer (SC-S80650, manufactured by Seiko Epson), the inkjet head was filled with the coloring compositions for each example, and the drive waveform of the inkjet head was optimized to ensure optimal ejection before creating the colored materials for each example. The nozzle density of the inkjet head nozzle row was set to 360 npi and 360 nozzles. A polyvinyl chloride film (Mactac5829R, manufactured by Mactac) was used as the material to be colored. The ink adhesion amount in the colored pattern during coloring was 5 mg / inch. 2 The color resolution was set to 1440 x 1440 dpi.

[0126] The colored portions of the resulting colored materials were measured for gloss at a tilt angle of 60° using a MINOLTA MULTI GLOSS 268 gloss meter, and evaluated according to the following evaluation criteria. A higher value tends to indicate a superior metallic luster. The evaluation results for gloss are shown in Tables 1-3. (Evaluation Criteria) A: Glossiness level of 400 or higher B: Glossiness is between 350 and 400 C: Glossiness is between 300 and 350 D: Glossiness is between 250 and 300 E: Glossiness is less than 250

[0127] 2.4. Dispersibility A 5% by mass suspension of a metal pigment containing 20kHz sonicated diethylene glycol diethyl ether, obtained during the manufacturing process of the above coloring composition, is partially removed. To this, Esream AD-374M (manufactured by NOF Corporation), a dispersant that exhibits good dispersibility in non-aqueous media, is added to disperse the metal particles to form a dispersion. Using a Microtrac MT-3300 (manufactured by Microtrac-Bell, a laser diffraction / scattering particle size distribution analyzer), the volume average particle size D of the metal particles contained in the dispersion is measured. 50 The value was measured and used as the reference value.

[0128] Next, 100 mL of the above coloring composition was placed in a glass container, sealed, and left at room temperature for one month. After shaking the container 10 times, the volume average particle size D of the metal pigment was measured for these coloring compositions using the above apparatus. 50 The following was measured: D from the above reference value before being placed in the constant temperature bath. 50 The rate of increase was determined, and the divergence was evaluated according to the following evaluation criteria: Volume average particle diameter D 50 The smaller the rate of increase, the more the metal pigment tends to disperse well. The results of the dispersibility evaluation are shown in Tables 1-3. (Evaluation Criteria) A: Particle size in ink (D 50 ) is less than 110% of the pulverized particle size. B: Particle size in ink (D 50 ) is between 110% and 150% of the pulverized particle size. C: Particle size in ink (D 50 ) is 150% or more but less than 200% of the crushed particle size. D: Particle size in ink (D 50 ) is between 200% and 500% of the crushed particle size. E: Particle size in ink (D 50 ) is 500% or more of the crushed particle size.

[0129] 3. Evaluation Results Tables 1-3 show the composition of the ink used in each example and the evaluation results. From Tables 1-3, the water-based coloring composition contains a metal pigment, water, and an organic solvent, and the metal pigment is surface-treated with a first surface treatment agent and a second surface treatment agent, the first surface treatment agent contains a phosphonic acid compound represented by formula (1) or a phosphoric acid compound represented by formula (2), the second surface treatment agent contains a phosphonic acid compound represented by formula (3) or a phosphoric acid compound represented by formula (4), and the R in the first surface treatment agent 1 or R 2 The number of carbon atoms in the second surface treatment agent is R 3 or R 4 It was found that water-based coloring compositions with a number of carbon atoms greater than the given number exhibit superior water resistance, gloss, and dispersibility. [Explanation of symbols]

[0130] 10...Coloring device, 11...Conveying path, 12...Feeding section, 14...Conveying section, 16...Belt conveying section, 18...Coloring section, 20...Fd discharge section, 22...Fd placement section, 24...Reversing path section, 26...Fu discharge section, 28...Fu placement section, 30...Feeding tray, 32...Feeding roller, 34...Conveying drive roller, 36...Conveying driven roller, 38...First roller, 40...Second roller, 42...None End belt, 42a... Upper section of endless belt, 44... Support, 46... Head holder, 48... Inkjet head, 50... First branching section, 52... Reversal path, 54... Second branching section, 56... Discharge roller pair, 64... Discharge drive roller, 68... Drive shaft, 76... Mounting surface, 78... Convex part, 80... First biasing member, 82... Second biasing member, 84, 86... Support shaft, P... Body to be colored.

Claims

1. A water-based coloring composition containing a metal pigment, water, and an organic solvent, The aforementioned metal pigment is surface-treated with a first surface treatment agent and a second surface treatment agent. The first surface treatment agent comprises a phosphonic acid compound represented by the following formula (1) or a phosphoric acid compound represented by the following formula (2). The second surface treatment agent comprises a phosphonic acid compound represented by the following formula (3) or a phosphoric acid compound represented by the following formula (4), (R) 1 )PO(OH) 2 (1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, in which the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group. (R) 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is an independent hydrocarbon group having 12 or more carbon atoms, in which hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group, and a is an integer of 1 or 2. (R) 3 )PO(OH) 2 (3) (In formula (3), R 3 This refers to a hydrocarbon group having 4 to 11 carbon atoms, in which case the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group. (R) 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is an independent hydrocarbon group having 4 to 11 carbon atoms, in which case the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group, and b is an integer of 1 or 2. R in the first surface treatment agent 1 or R 2 The number of carbon atoms is R in the second surface treatment agent. 3 or R 4 More than the number of carbon atoms, The aqueous coloring composition is a paint composition or an inkjet ink composition.

2. R in the first surface treatment agent 1 or R 2 The number of carbon atoms and the R in the second surface treatment agent. 3 or R 4 The difference in the number of carbon atoms is between 4 and 14. The aqueous coloring composition according to claim 1.

3. The water content is 50% by mass or more and 90% by mass or less, relative to the total amount of the aqueous coloring composition. The aqueous coloring composition according to claim 1.

4. The content of the organic solvent is 10% by mass or more and 60% by mass or less, based on the total amount of the aqueous coloring composition. The aqueous coloring composition according to claim 1.

5. The content of the metal pigment is 0.5% by mass or more and 20% by mass or less, based on the total amount of the aqueous coloring composition. The aqueous coloring composition according to claim 1.

6. The aforementioned metallic pigment is made of aluminum or an aluminum alloy. The aqueous coloring composition according to claim 1.

7. The process comprises the step of applying the aqueous coloring composition according to any one of claims 1 to 6 to an object to be colored. Coloring method.

8. A pigment dispersion containing a metal pigment, water, and an organic solvent, The aforementioned metal pigment is surface-treated with a first surface treatment agent and a second surface treatment agent. The first surface treatment agent comprises a phosphonic acid compound represented by the following formula (1) or a phosphoric acid compound represented by the following formula (2). The second surface treatment agent comprises a phosphonic acid compound represented by the following formula (3) or a phosphoric acid compound represented by the following formula (4), (R) 1 )PO(OH) 2 (1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, in which the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group. (R) 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is an independent hydrocarbon group having 12 or more carbon atoms, in which hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group, and a is an integer of 1 or 2. (R) 3 )PO(OH) 2 (3) (In formula (3), R 3 This refers to a hydrocarbon group having 4 to 11 carbon atoms, in which case the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group. (R) 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is an independent hydrocarbon group having 4 to 11 carbon atoms, in which case the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group, and b is an integer of 1 or 2. R in the first surface treatment agent 1 or R 2 The number of carbon atoms is R in the second surface treatment agent. 3 or R 4 More than the number of carbon atoms, Pigment dispersion.

9. A first surface treatment step involves surface-treating a metal pigment with a first surface treatment agent, The process includes a second surface treatment step in which the metal pigment, which has been surface-treated with the first surface treatment agent, is surface-treated with a second surface treatment agent. The first surface treatment agent comprises a phosphonic acid compound represented by the following formula (1) or a phosphoric acid compound represented by the following formula (2). The second surface treatment agent comprises a phosphonic acid compound represented by the following formula (3) or a phosphoric acid compound represented by the following formula (4), (R) 1 )PO(OH) 2 (1) (In formula (1), R 1 This refers to a hydrocarbon group having 12 or more carbon atoms, in which the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group. (R) 2 O) a PO(OH) 3-a (2) (In formula (2), R 2 Each of these is an independent hydrocarbon group having 12 or more carbon atoms, in which the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group, and a is an integer of 1 or 2. (R) 3 )PO(OH) 2 (3) (In formula (3), R 3 This refers to a hydrocarbon group having 4 to 11 carbon atoms, in which case the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group. (R) 4 O) b PO(OH) 3-b (4) (In formula (4), R 4 Each of these is an independent hydrocarbon group having 4 to 11 carbon atoms, in which case the hydrogen atoms may be substituted with a carboxyl group, a hydroxyl group, an amino group, or an oxyalkylene group, and b is an integer of 1 or 2. R in the first surface treatment agent 1 or R 2 The number of carbon atoms is R in the second surface treatment agent. 3 or R 4 More than the number of carbon atoms, A method for producing metallic pigments.

10. In the first surface treatment step, surface treatment is performed using the first surface treatment agent in a solvent-based medium. A method for producing a metal pigment according to claim 9.

11. In the second surface treatment step, surface treatment is performed in an aqueous medium using the second surface treatment agent. A method for producing a metal pigment according to claim 9.

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