JP2005325282A - Method for producing colored dispersion, ink for inkjet recording, inkjet recording method, ink cartridge and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a colored dispersion that has excellent storage stability and provides an image having high color development and high fastness and ink for inkjet recording that stably records an image having excellent color development and fastness. <P>SOLUTION: The method for producing the colored dispersion consisting essentially of a water-insoluble colorant used for ink, a polymer dispersant and water comprises a first process to a fourth process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a colored dispersion, an ink for ink jet recording, an ink jet recording method, an ink cartridge, and an ink jet recording apparatus. More specifically, a method for producing a colored dispersion having high dispersion stability and good color development of a printed image, an ink for inkjet recording using the colored dispersion produced by the production method, an inkjet recording method, an ink cartridge, and inkjet recording Relates to the device.

  Conventionally, water-insoluble colorants such as pigments having excellent fastness such as water resistance and light resistance have been widely used as colorants for printing inks. However, in order to use the water-insoluble color material as the color material of the water-based ink, it is required to stably disperse the water-insoluble color material in the aqueous medium. Therefore, a color material dispersion type water-based ink is used in which a dispersant such as a polymer compound or a surfactant is added to uniformly disperse a water-insoluble color material in an aqueous medium.

  In recent years, also in ink jet recording applications, this color material dispersion type aqueous ink has been used as an ink for ink jet recording from the viewpoint of image fastness. In ink jet recording, attempts have been made to impart a coagulation function or a water insolubilization function to a color material dispersion in ink in order to improve the fixability and water resistance of ink on paper. However, by imparting such a function to the color material dispersion, the dispersion stability of the color material particles in the ink decreases, and the color material particles aggregate during storage of the ink and the concentration of the ink. There are problems that unevenness and sedimentation are likely to occur, clogging occurs due to ink drying at the nozzle tip of the ink jet device, and discharge stability is likely to be reduced.

In order to solve the above problems, Patent Documents 1 and 2 propose inks in which water-insoluble color materials are encapsulated. In these inks prepared by mixing a water-insoluble colorant and a dispersing agent and treating with a disperser or by introducing an organic solvent phase containing a pigment and a polymer compound into water, the particle size becomes large. Therefore, in the printed image, the saturation is lowered due to the irregular reflection of light on the surface of the color material aggregate, so that the color development is insufficient as compared with the ink using the water-soluble dye.
Japanese Patent No. 2562634 JP 2002-226743 A

  An object of the present invention was made in view of the above problems, and is to produce a colored dispersion that can provide an image having good dispersion stability, high color development, and high fastness, and Is to provide an ink for ink jet recording, an ink jet recording method, an ink cartridge, and an ink jet recording apparatus capable of stably recording an image excellent in color development and fastness at any time.

As a result of intensive studies to solve the above problems, the present inventors have found that the following problems can be solved. That is, the present invention relates to a method for producing a colored dispersion mainly comprising a water-insoluble colorant, a polymer dispersant, and water used for recording ink.
(1) a first step of dissolving a water-insoluble colorant soluble in a water-soluble organic solvent and a polymer dispersant having an unneutralized anionic hydrophilic group in the water-soluble organic solvent;
(2) a second step of adding water to the solution prepared in the first step,
(3) a third step of adding an aqueous solution containing a neutralizing agent capable of neutralizing the polymer dispersant to the solution prepared in the second step;
(4) a fourth step for removing the organic solvent in the aqueous solution prepared in the third step;
A method for producing a colored dispersion characterized by comprising:

  In the present invention, the amount of water added in the second step is the same as the water content ratio (mass ratio, hereinafter the same) in the organic solvent-water mixed solution after the addition of water. Adjust to be 0.3 to 2.0 times, preferably 0.5 to 1.5 times, more preferably 0.8 to 1.0 times the minimum water content ratio to precipitate The amount of water added in the second step is the water content ratio in the organic solvent-water mixed solution after the addition of water, and the lowest water content in which the water-insoluble colorant precipitates from the dissolved state. The addition amount adjusted to be in the range of 0.3 to 2.0 times, preferably 0.5 to 1.5 times the ratio; the water-soluble organic solvent is a cyclic ether The water-insoluble colorant is an oil-soluble dye; It ON compound is a colorant which is water insoluble; and a neutralizing agent capable of neutralizing the polymer dispersant is preferably an alkali metal compound.

  In the present invention, the polymer dispersant is a block copolymer comprising at least one hydrophobic block and at least one hydrophilic block, and each block is composed of a vinyl ether monomer. It is a polymer dispersant; a hydrophilic block of the polymer dispersant is composed of a vinyl ether monomer having a nonionic hydrophilic group, and a block composed of a vinyl ether monomer having an anionic hydrophilic group The polymer dispersant is composed of a block composed of a hydrophobic vinyl ether monomer, a block composed of a hydrophilic vinyl ether monomer having a nonionic hydrophilic group, and a hydrophilic group having an anionic hydrophilic group. At least in the order of the block composed of vinyl ether monomer It is preferably made of.

  Further, the present invention is an ink jet recording ink mainly composed of a water-insoluble colorant, a polymer dispersant, a water-soluble organic solvent, and water, characterized by containing the colored dispersion prepared by the production method of the present invention. An ink for inkjet recording (hereinafter simply referred to as “ink”) is provided.

  Furthermore, the present invention provides an ink jet recording method in which energy is applied to an ink, the ink is ejected and applied to a recording material, and the ink contains a colored dispersion produced by the production method of the present invention. An ink jet recording method is provided. In the ink jet recording method, the energy is preferably thermal energy; the recording material is preferably a recording material having a coating layer that receives ink on at least one surface.

  Further, the present invention provides an ink cartridge including an ink storage portion that stores ink, wherein the ink contains a colored dispersion produced by the manufacturing method of the present invention; An ink jet recording apparatus comprising an ink cartridge having an ink storage portion and a head portion for discharging the ink, wherein the ink contains a colored dispersion produced by the production method of the present invention. An inkjet recording apparatus is provided.

  According to the present invention, it is possible to produce a colored dispersion that can provide an image having good dispersion stability, high color developability and high fastness, and furthermore, good discharge performance and good color developability and fastness. It is possible to provide an ink, an ink jet recording method, an ink cartridge, and an ink jet recording apparatus capable of stably recording an image having excellent properties at any time.

  In the case of producing a color material powder, after the color material is once dissolved and made into a single molecule, the color material molecules are aggregated into fine particles by mechanically crushing a mass of the color material such as pigment. Compared to the method of producing particles, it is often used because it can produce fine particles having a small particle size and a narrow particle size distribution. However, when preparing an aqueous dispersion of a water-insoluble colorant, a method is generally used in which a dispersion is prepared by mechanically kneading and pulverizing the colorant powder and the dispersant together. The method of making particles is rarely performed because it is difficult to simultaneously control the aggregation operation and dispersion operation of the coloring material, and it is difficult to produce a stable aqueous dispersion. In particular, only inks that use an aqueous dispersion of a water-insoluble color material prepared by mechanically kneading and pulverizing a color material powder and a dispersant have been put to practical use.

In the method for producing a colored dispersion mainly composed of a water-insoluble colorant, a polymer dispersant and water used in the ink,
(1) a first step of dissolving a water-insoluble colorant soluble in a water-soluble organic solvent and a polymer dispersant having an unneutralized anionic hydrophilic group in the water-soluble organic solvent;
(2) a second step of adding water to the solution prepared in the first step,
(3) a third step of adding an aqueous solution containing a neutralizing agent capable of neutralizing the polymer dispersant to the solution prepared in the second step;
(4) a fourth step for removing the organic solvent in the aqueous solution prepared in the third step;
It has been found that a colored dispersion that can provide an image having good dispersion stability, high color developability, and high fastness can be produced by having at least.

  When water is added to a water-insoluble color material that has become monomolecular in an organic solvent, the water-insoluble color material precipitates from the solution to form fine particles, and the polymer particles surround the deposited fine particles to form a water-insoluble color material. Form a dispersion of material. The inventors of the present invention introduced water into the water-insoluble colorant that has become monomolecular in the organic solvent, and the polymer dispersant surrounds the fine particles from which the water-insoluble colorant has precipitated from the solution, thereby dispersing the water-insoluble colorant. As a result of diligent investigation focusing on the conditions for forming the body, there are significant differences in the particle size and stability of the resulting water-insoluble colorant depending on the dissolution state of the polymer dispersant in the organic solvent-water mixed solution. And by accurately controlling the solubility of the polymer dispersant in the organic solvent-water mixed solution, it is possible to prepare a dispersion of a water-insoluble colorant with fine particles and good dispersion stability. did.

  In general, when a water-insoluble colorant and a polymer dispersant are dissolved in an organic solvent and water is added to the solution, the water-insoluble colorant once precipitates. Surrounds to form a dispersion of water-insoluble colorant. At this time, the particle size and stability of the formed dispersion of the water-insoluble colorant are large due to the balance between the phenomenon of precipitation of the water-insoluble colorant and the phenomenon of surrounding the precipitated water-insoluble colorant with the polymer dispersant. It seems to be affected.

  As in the present invention, a polymer dispersant having an unneutralized anionic hydrophilic group is used as the polymer dispersant, and when dissolved in an organic solvent together with a water-insoluble colorant, the polymer dispersant has a neutralized anionic hydrophilic group. Compared to the case of using a polymer dispersant, the solubility of the neutralized anionic hydrophilic group in the organic solvent is low, so the polymer dispersant does not become monomolecular and is strong between the polymer dispersants. In contrast to the interaction, once a uniform system is formed in which each molecule is a single molecule, the interaction between the hydrophobic group of the polymer dispersant and the water-insoluble colorant becomes strong. When water is added in such a state, the solubility of the water-insoluble colorant in the organic solvent-water mixed solution and the solubility of the hydrophobic group of the polymer dispersant in the organic solvent-water mixed solution are reduced. That is, the interaction between the water-insoluble colorant and the solvent, the interaction between the hydrophobic group of the polymer dispersant and the solvent is reduced, and the interaction between the hydrophobic group of the polymer dispersant and the water-insoluble colorant is further reduced. Become stronger. Next, an aqueous solution containing a neutralizing agent without first adding water by adding an aqueous solution containing a neutralizing agent that functions to ionize the anionic hydrophilic group of the polymer dispersant to enhance hydrophilicity Compared with the case of adding only the water-insoluble colorant and the polymer dispersant are easily formed, that is, a dispersion in which the water-insoluble colorant is surrounded by the polymer dispersant is stably formed and the particles It is considered that a dispersion having a small diameter and excellent dispersion stability can be formed.

The production method of the present invention will be described in more detail. FIG. 1 shows a flowchart of the manufacturing method of the present invention.
The present invention relates to a method for producing a colored dispersion mainly comprising a water-insoluble colorant, a polymer dispersant, and water used in an ink.
(1) a first step of dissolving a water-insoluble colorant soluble in a water-soluble organic solvent and a polymer dispersant having an unneutralized anionic hydrophilic group in the water-soluble organic solvent;
(2) a second step of adding water to the solution prepared in the first step,
(3) a third step of adding an aqueous solution containing a neutralizing agent capable of neutralizing the polymer dispersant to the solution prepared in the second step;
(4) a fourth step for removing the organic solvent in the aqueous solution prepared in the third step;
Is a method for producing a colored dispersion having at least

  In the first step, a water-insoluble coloring material and a polymer dispersant having an unneutralized anionic hydrophilic group may be dissolved in a water-soluble organic solvent. At this time, it is preferable that the water-insoluble colorant and the polymer dispersant are completely dissolved in the water-soluble organic solvent. When dissolving the water-insoluble colorant and the polymer dispersant in the water-soluble organic solvent, a method of dissolving by heating or a method of removing insoluble matters by filtration or the like can also be used.

  In said 2nd process, it is adding water to the solution produced at the 1st process, and if it is water which does not contain the neutralizing agent which can neutralize a polymer dispersing agent as water to add, other components The thing containing can also be used. The amount of water added is preferably adjusted as follows because a colored dispersion having a smaller particle size and good dispersion stability can be obtained. The water content ratio in the organic solvent-water mixed solution after addition of water is preferably in the range of 0.3 to 2.0 times the minimum water content ratio at which the polymer dispersant precipitates from the dissolved state. More preferably, it is adjusted to a range of 0.5 to 1.5 times, and more preferably 0.8 to 1.0 times. Alternatively, the water content ratio in the organic solvent-water mixed solution after addition of water is preferably in the range of 0.3 to 2.0 times the minimum water content ratio at which the water-insoluble colorant precipitates from the dissolved state. More preferably, it is adjusted to a range of 0.5 to 1.5 times. When adding water to the solution prepared in the first step, it is preferable to add so that the concentration unevenness is reduced, such as a method of adding the solution phase to be added while stirring, a method of adding water by spraying, etc. Is mentioned.

  In the third step, an aqueous solution containing a neutralizing agent capable of neutralizing the polymer dispersant is added to the solution prepared in the second step, and the polymer dispersant is used as the aqueous solution to be added. As long as it contains a neutralizing neutralizing agent, those containing other components can also be used. As the amount of the neutralizing agent to be added, it is preferable to add an equivalent amount or more with respect to the anionic group of the polymer dispersant. When adding an aqueous solution containing a neutralizing agent to the solution prepared in the second step, it is preferable to add it so that the concentration unevenness is reduced. And the like.

In the fourth step, it is only necessary to remove the organic solvent in the aqueous solution prepared in the third step, and it is not necessary to completely remove the organic solvent, but the organic solvent content ratio in the organic solvent-water mixed solution It is preferable that the insoluble colorant be less than 0.01 times the minimum organic solvent content ratio that precipitates from the dissolved state. As a method for removing the organic solvent, a method of removing by heating or a method of removing under reduced pressure is preferable.
The average particle diameter of the colorant, which is a combination of the water-insoluble colorant and the polymer dispersant in the colored dispersion obtained through the first step to the fourth step, is preferably 170 nm or less, and more preferably in the range of 50 to 120 nm. Particularly preferred. When the particle diameter is larger than 170 nm, there is a risk that the dispersion stability is lowered and the ejection stability when these color materials are used becomes insufficient.

Next, various materials used in the production method of the present invention will be described.
(Water-soluble organic solvent)
As the water-soluble organic solvent used in the production method of the present invention, any organic solvent having solubility in water and capable of dissolving the water-insoluble colorant used can be used alone or in combination of two or more. can do. Among these, highly volatile organic solvents such as alcohols, ethers, and ketones that can be easily removed from a mixed solution with water by a method such as distillation are preferable, and cyclic ethers are more preferable because they can easily form a more stable dispersion.

  The cyclic ether is preferably at least one selected from the group consisting of dimethylfuran, tetrahydrofuran, methyltetrahydrofuran, dimethoxytetrahydrofuran and dioxane, more preferably tetrahydrofuran, and the tetrahydrofuran makes the colorant dispersion more stable. This is desirable.

(Water-insoluble colorant)
The water-insoluble colorant used in the production method of the present invention is a colorant that hardly dissolves in water, and any colorant that dissolves in the water-soluble organic solvent can be used. Specifically, the colorant has a solubility in water of preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and the solubility in the water-soluble organic solvent is preferably 1.0% by mass. More preferably, the colorant is 5.0% by mass or more. As such a color material, an oil-soluble dye is preferable, and a color material obtained by water-insolubilizing an anionic dye with a cationic compound is preferable because a stable dispersion is formed.

Examples of water-insoluble colorants are shown below, but are not limited thereto.
Examples of oil-soluble dyes include C.I. I. Solvent Yellow 1, 2, 3, 13, 14, 19, 21, 22, 29, 36, 37, 38, 39, 40, 42, 43, 44, 45, 47, 62, 63, 71, 76, 79, 81, 82, 83: 1, 85, 86, 88, 151; C.I. I. Solvent Red 8, 27, 35, 36, 37, 38, 39, 40, 49, 58, 60, 65, 69, 81, 83: 1, 86, 89, 91, 92, 97, 99, 100, 109, 118, 119, 122, 127, 218; I. Solvent Blue 14, 24, 25, 26, 34, 37, 38, 39, 42, 43, 44, 45, 48, 52, 53, 55, 59, 67, 70; C.I. I. Solvent black 3, 5, 7, 8, 14, 17, 19, 20, 22, 24, 26, 27, 28, 29, 43, 45 etc. are mentioned.

  The coloring material obtained by water-solubilizing an anionic dye with a cationic compound is an ion complex of an anionic dye and a cationic compound, and a dye having an acidic group such as a sulfonic acid group or a carboxylic acid group in the pigment skeleton, Compounds having cationic properties such as primary, secondary and tertiary amine salts and quaternary ammonium salts, preferably primary, secondary and tertiary amine salts and quaternary ammonium salts having a hydrophobic group An ion complex with a cationic surfactant such as is desirable.

  Examples of the anionic dye include C.I. I. Direct black 17, 19, 22, 32, 38, 51, 62, 71, 108, 146, 154; I. Direct Yellow 12, 24, 26, 44, 86, 87, 98, 100, 130, 142, C.I. I. Direct Red 1, 4, 13, 17, 23, 28, 31, 62, 79, 81, 83, 89, 227, 240, 242, 243; I. Direct Blue 6, 22, 25, 71, 78, 86, 90, 106, 199; I. Direct orange 34, 39, 44, 46, 60; I. Direct violet 47, 48; C.I. I. Direct Brown 109; C.I. I. Direct Green 59; C.I. I. Acid Black 2, 7, 24, 26, 31, 52, 63, 112, 118, 168, 172, 208; I. Acid Yellow 11, 17, 23, 25, 29, 42, 49, 61, 71; C.I. I. Acid Red 1, 6, 8, 32, 37, 51, 52, 80, 85, 87, 92, 94, 115, 180, 254, 256, 289, 315, 317; I. Acid Blue 9, 22, 40, 59, 93, 102, 104, 113, 117, 120, 167, 229, 234, 254; C.I. I. Acid Orange 7, 19; I. Acid Violet 49; C.I. I. Reactive black 1, 5, 8, 13, 14, 23, 31, 34, 39; I. Reactive Yellow 2, 3, 13, 15, 17, 18, 23, 24, 37, 42, 57, 58, 64, 75, 76, 77, 79, 81, 84, 85, 87, 88, 91, 92 93, 95, 102, 111, 115, 116, 130, 131, 132, 133, 135, 137, 139, 140, 142, 143, 144, 145, 146, 147, 148, 151, 162, 163; C . I. Reactive Red 3, 13, 16, 21, 22, 23, 24, 29, 31, 33, 35, 45, 49, 55, 63, 85, 106, 109, 111, 112, 113, 114, 118, 126 128, 130, 131, 141, 151, 170, 171, 174, 176, 177, 183, 184, 186, 187, 188, 190, 193, 194, 195, 196, 200, 201, 202, 204, 206 218, 221; C.I. I. Reactive Blue 2, 3, 5, 8, 10, 13, 14, 15, 18, 19, 21, 25, 27, 28, 38, 39, 40, 41, 49, 52, 63, 71, 72, 74 75, 77, 78, 79, 89, 100, 101, 104, 105, 119, 122, 147, 158, 160, 162, 166, 169, 170, 171, 172, 173, 174, 176, 179, 184 190, 191, 194, 195, 198, 204, 211, 216, 217; I. Reactive Orange 5, 7, 11, 12, 13, 15, 16, 35, 45, 46, 56, 62, 70, 72, 74, 82, 84, 87, 91, 92, 93, 95, 97, 99 C. I. Reactive violet 1, 4, 5, 6, 22, 24, 33, 36, 38; I. Reactive green 5, 8, 12, 15, 19, 23; C.I. I. Reactive brown 2, 7, 8, 9, 11, 16, 17, 18, 21, 24, 26, 31, 32, 33; C.I. I. Food black 1, 2; C.I. I. Food Yellow 3; C.I. I. Food red 87, 92, 94 etc. are mentioned.

Cationic surfactants include, for example, decyltrimethylammonium, dodecyltrimethylammonium, tetradecyltrimethylammonium, hexadecyltrimethylammonium, octadecyltrimethylammonium, didodecyldimethylammonium, dimethylditetradecylammonium, dimethyldioctadecylammonium, dimethyldi Examples include chloride salts and bromide salts such as palmityl ammonium, dodecyldimethylbenzylammonium, benzyloctadecyldimethylammonium, benzyltrimethylammonium, and benzalkonium.
The amount of the water-insoluble colorant added in the production method of the present invention is preferably 0.1 to 20% by mass, more preferably 1.0 to 10% by mass, based on the total mass of the obtained colored dispersion. It is.

(Polymer dispersant)
As the polymer dispersant used in the production method of the present invention, any conventionally known polymer dispersant can be used as long as it is a polymer dispersant having an anionic group. A polymer dispersant having both an anionic hydrophilic group-containing block is preferred. In particular, it is more stable when the polymer dispersant is a block copolymer composed of at least one hydrophobic block and at least one hydrophilic block, and each block is composed of a vinyl ether monomer. This is preferable because a stable colorant dispersion is formed. In this case, the polymer dispersant has at least one type of hydrophilic block and at least one type of hydrophobic block, and each block may be a block copolymer composed of a vinyl ether monomer. Those having the above hydrophilic block or two or more types of hydrophobic blocks can be used, and a single block copolymer or a mixture of two or more types of block copolymers can also be used. Examples of the form of the copolymer include a linear type and a graft type, and a linear type block copolymer is preferable.

The polymer dispersant used in the present invention preferably has a repeating unit structure represented by the following general formula (1), for example.
^{_{- (CH 2 -CH (OR 1}} )) - (1)
In the general formula (1), R ¹ represents an aliphatic hydrocarbon such as an alkyl group, an alkenyl group, a cycloalkyl group, or a cycloalkenyl group, a phenyl group, a pyridyl group, a benzyl group, a toluyl group, a xylyl group, An aromatic hydrocarbon group in which a carbon atom may be substituted with a nitrogen atom, such as an alkylphenyl group, a phenylalkylene group, a biphenyl group, and a phenylpyridyl group. Moreover, the hydrogen atom on the aromatic ring may be substituted with a hydrocarbon group. R ¹ preferably has 1 to 18 carbon atoms.

R ¹ may be a group represented by — (CH (R ² ) —CH (R ³ ) —O) _p —R ⁴ or — (CH ₂ ) _m — (O) _n —R ⁴ . In this case, R ² and R ³ each independently represent a hydrogen atom or a methyl group, and R ⁴ represents an aliphatic hydrocarbon such as an alkyl group, an alkenyl group, a cycloalkyl group, or a cycloalkenyl group, a phenyl group, Aromatic hydrocarbon groups in which carbon atoms may be substituted with nitrogen atoms, such as pyridyl group, benzyl group, toluyl group, xylyl group, alkylphenyl group, phenylalkylene group, biphenyl group, phenylpyridyl group (aromatic The hydrogen atom on the ring may be substituted with a hydrocarbon group), —CHO, —CH ₂ CHO, —CO—CH═CH ₂ , —CO—C (CH ₃ ) ═CH ₂ , —CH ₂ —CH═CH ₂ , —CH ₂ —C (CH ₃ ) ═CH ₂ , —CH ₂ —COOR ^5, etc., and the hydrogen atom in these groups is fluorine, as long as it is chemically possible. salt , It may be substituted with a halogen atom such as bromine. R ⁴ preferably has 3 to 18 carbon atoms. R ⁵ is hydrogen or an alkyl group. p is preferably 1 to 18, m is preferably 1 to 36, and n is preferably 0 or 1.

In R ¹ and R ⁴ , examples of the alkyl group or alkenyl group include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl. , Tetradecyl, hexadecyl, octadecyl, oleyl, linoleyl and the like, and examples of the cycloalkyl group or cycloalkenyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclohexenyl and the like.

  The structures of the vinyl ether monomers (Ia to Io) and the polymer dispersants (II-a to II-e) constituting the polymer dispersant used in the present invention are exemplified below. The polyvinyl ether structure of the polymer dispersant used is not limited to these.

  Furthermore, it is preferable that the number of repeating units of the polyvinyl ether block (in the above (II-a to II-e), m, n, l) is independently 1 to 10,000. Moreover, it is more preferable that the sum total is (m + n + 1) in the above (II-a to II-e), and 10 to 20,000. The number average molecular weight is preferably 500 to 20,000,000, more preferably 1,000 to 5,000,000, and most preferably 2,000 to 2,000,000. The proportion of these polymer dispersants in the colored dispersion is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total mass of the colored dispersion. In addition, the content ratio of the polymer dispersant (A) and the water-insoluble colorant (B) in the colored dispersion is A: B = 1: 100 to 2: 1 in terms of solid content mass ratio. It is desirable from the viewpoint of ink ejection stability and dispersion stability when a colored dispersion is used for ink.

  A method for synthesizing a copolymer (polymer dispersing agent) having a vinyl ether polymer block is not particularly limited, but cation living polymerization by Aoshima et al. (Japanese Patent Laid-Open Nos. 11-322942 and 11-322866) can be used. Preferably used. By using the cationic living polymerization method, we can synthesize various polymers such as homopolymers with exactly the same length (molecular weight), copolymers of two or more monomers, and block copolymers, graft copolymers, and gradation copolymers. be able to. Various functional groups can be introduced into the side chain of the polyvinyl ether block.

(Neutralizer)
The neutralizing agent used in the production method of the present invention can neutralize the anionic hydrophilic group of the polymer dispersant and can be used as long as it dissolves in water. Examples of such a neutralizing agent include alkali metal compounds such as sodium hydroxide and potassium hydroxide, amines such as monoethanolamine and triethanolamine, and ammonia. Coloring obtained when an alkali metal compound is used. This is preferable because the stability of the dispersion is further improved.

  Next, the case where the colored dispersion prepared by the above production method is used for ink will be described. The ink of the present invention is an ink mainly comprising a water-insoluble colorant, a polymer dispersant, a water-soluble organic solvent, and water, and containing the colored dispersion prepared by the production method described above. Various materials used in the ink of the present invention will be described.

(Water-insoluble colorant)
The colored dispersion prepared by the above production method is preferably used alone, but other than this, a water-insoluble colorant can be used in combination. The water-insoluble color material used in combination is a color material having a solubility in water of preferably 0.5% by mass or less, more preferably 0.1% by mass or less. Examples of such coloring materials include oil-soluble dyes, vat dyes, disperse dyes, and pigments. The total content of the water-insoluble colorant in the ink of the present invention is preferably in the range of 0.1 to 20% by mass, more preferably 1.0 to 10% by mass with respect to the total mass of the ink. If the amount of the water-insoluble colorant is less than 0.1% by mass, it may be difficult to obtain a sufficient image density. If the amount exceeds 20% by mass, the ink ejection stability may be caused by ink clogging at the nozzle. Is likely to occur.

(Water-soluble organic solvent)
As the water-soluble organic solvent used in the ink of the present invention, any water-soluble organic solvent can be used, and it can be used as a mixed solvent of two or more water-soluble organic solvents. Even when the water-soluble organic solvent is contained in the colored dispersion prepared by the above production method, it is preferable to use another water-soluble organic solvent in combination.

  Specific examples of preferred water-soluble organic solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol and other lower alcohols; ethylene glycol, diethylene glycol, Triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, thiodiglycol, 1,4-cyclohexanediol Diols such as: Triols such as glycerin, 1,2,4-butanetriol, 1,2,6-hexanetriol, 1,2,5-pentanetriol; trimethylolpro Hindered alcohols such as ethylene, trimethylolethane, neopentyl glycol, pentaerythritol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoallyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether , Glycol ethers such as diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether; dimethyl sulfoxide, glycerin monoallyl ether, polyethylene glycol, N-methyl-2 -Pi Examples include lidone, 2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, sulfolane, β-dihydroxyethylurea, urea, acetonylacetone, dimethylformamide, dimethylacetamide, acetone, diacetone alcohol, etc. .

  Among these, it is preferable to use a water-soluble organic solvent having a boiling point of 120 ° C. or more because ink concentration at the nozzle tip is suppressed. The proportion of these water-soluble organic solvents in the ink is preferably 5 to 50% by mass and more preferably 10 to 30% by mass with respect to the total mass of the ink.

(Polymer dispersant)
The colored dispersion prepared by the above production method is preferably used alone, but other polymer dispersants can be used in combination. As the polymer dispersant to be used in combination, the polymer dispersant described in the above production method may be used, but other polymer dispersants may be used. The proportion of the polymer dispersant in the ink is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass with respect to the total mass of the ink.

  The above are the essential components of the ink of the present invention. In addition to these components, various additives such as a surfactant, a pH adjuster, an antioxidant, and an antifungal agent may be added. Among these additives, aluminum or aluminum compounds such as aluminum hydroxide, aluminum oxide, tripropylaluminum, triisopropylaluminum, aluminum compounds of Ziegler-Natta catalyst, and metal aluminum powder are used as additives in the ink. Preferably, when aluminum hydroxide or aluminum oxide is contained, aluminum or aluminum compound acts on the hydrophobic block and hydrophilic block of the polymer dispersant, thereby improving the bond between the polymer dispersants. Colorant particle capsules are desirable because they are more stable. The amount of aluminum or aluminum compound added is preferably a molar ratio of the polymer dispersant (A) to aluminum (B) in the ink, preferably A: B = 3,000: 1 to 1: 5. Is more preferably 300: 1 to 20: 1 because the stability of the capsule of the colorant particles made of the polymer dispersant is improved.

  A feature of the ink jet recording method of the present invention is that the ink of the present invention is used in an ink jet recording method performed by applying energy to the ink and causing the ink to fly. As the energy, thermal energy or mechanical energy can be used, but it is preferable to use thermal energy.

  In the ink jet recording method of the present invention, the recording material is not limited, but a recording material having a coating layer that accepts ink on at least one side, which is called a so-called inkjet special paper, is preferably used. As the recording material having a coating layer, a recording material having a coating layer for receiving ink on at least one surface containing at least a hydrophilic polymer and / or an inorganic porous material is desirable.

Next, an example of the ink jet recording apparatus of the present invention suitable for performing recording using the ink of the present invention will be described below.
(Inkjet recording device using thermal energy)
First, an example of a head configuration which is a main part of an ink jet recording apparatus using thermal energy is shown in FIGS. 2 is a cross-sectional view of the head 13 along the ink flow path, and FIG. 3 is a cross-sectional view taken along the line AB of FIG. The head 13 is obtained by adhering a heating element substrate 15 and a glass, ceramic, silicon, or plastic plate having a flow path (nozzle) 14 through which ink passes. The heating element substrate 15 includes a protective layer 16 formed of silicon oxide, silicon nitride, silicon carbide, etc., electrodes 17-1 and 17-2 formed of aluminum, gold, aluminum-copper alloy, etc., HfB ₂ , TaN, TaAl From a heating resistor layer 18 formed from a high melting point material such as, a heat storage layer 19 formed from thermal silicon oxide, aluminum oxide, or the like, and a substrate 20 formed from a material with good heat dissipation such as silicon, aluminum, aluminum nitride, etc. It has become.

  When pulsed electrical signals are applied to the electrodes 17-1 and 17-2 of the head 13, the region indicated by n of the heating element substrate 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact with the surface. The pressure causes the meniscus 23 to protrude, and the ink 21 is ejected through the nozzles 14 of the head to form ink droplets 24 from the ejection orifices 22 and fly toward the recording material 25. FIG. 4 shows an external view of an example of a multi-head in which many heads shown in FIG. 2 are arranged. This multi-head is made by adhering a glass plate 27 having multi-nozzles 26 and a heating head 28 similar to that described in FIG.

  FIG. 5 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 5, reference numeral 61 denotes a blade as a wiping member, one end of which is held and fixed by a blade holding member, and forms a cantilever. The blade 61 is disposed at a position adjacent to the recording area by the recording head 65, and in this example, is held in a form protruding in the moving path of the recording head 65.

  Reference numeral 62 denotes a cap on the projection port surface of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, contacts the ink ejection port surface, and performs capping. The structure to perform is provided. Further, reference numeral 63 denotes an ink absorber provided adjacent to the blade 61 and, like the blade 61, is held in a form protruding in the moving path of the recording head 65. The blade 61, the cap 62, and the ink absorber 63 constitute a discharge recovery portion 64, and the blade 61 and the ink absorber 63 remove moisture, dust, and the like from the discharge port surface.

  Reference numeral 65 denotes a recording head which has discharge energy generating means and performs recording by discharging ink onto a recording material facing the discharge port surface on which the discharge port is arranged. Reference numeral 66 denotes a recording head mounted with the recording head 65. It is a carriage for moving. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 (not shown) driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording area by the recording head 65 and its adjacent area can be moved.

  Reference numeral 51 denotes a paper feed unit for inserting a recording material, and 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection port surface of the recording head 65, and is discharged to a paper discharge unit provided with a paper discharge roller 53 as recording progresses. In the above configuration, when the recording head 65 finishes recording and returns to the home position, the cap 62 of the ejection recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. As a result, the ejection port of the recording head 65 is wiped.

  When the cap 62 is in contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving path of the recording head. When the recording head 65 is moved from the home position to the recording start position, the cap 62 and the blade 61 are in the same position as the wiping position described above. As a result, the ejection port surface of the recording head 65 is wiped even during this movement. The above-mentioned movement of the recording head to the home position is not only at the end of recording or at the time of ejection recovery, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves the recording area for recording. Then, the wiping is performed with this movement.

  FIG. 6 is a diagram illustrating an example of an ink cartridge 45 that contains ink supplied to the recording head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink container, for example, an ink bag, in which supply ink is stored, and a rubber plug 42 is provided at the tip thereof. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the head. An ink absorber 44 receives waste ink. The ink container preferably has a liquid contact surface made of polyolefin, particularly polyethylene.

  The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, and is preferably used in an apparatus in which they are integrated as shown in FIG. It is done. In FIG. 7, reference numeral 70 denotes a recording unit, in which an ink storage portion that stores ink, for example, an ink absorber is stored, and the ink in the ink absorber from the head portion 71 having a plurality of orifices. It is configured to be ejected as ink droplets. It is preferable for the present invention to use polyurethane as the material of the ink absorber. Alternatively, a structure in which the ink container is an ink bag with a spring or the like inside without using an ink absorber may be used. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 4 and is detachable from the carriage 66.

(Inkjet recording device using mechanical energy)
Next, as a preferable example of an ink jet recording apparatus using mechanical energy, a nozzle forming substrate having a plurality of nozzles, a pressure generating element made of a piezoelectric material and a conductive material disposed opposite to the nozzles, and the pressure An on-demand ink jet recording head that includes ink that fills the periphery of the generating element, displaces the pressure generating element by an applied voltage, and discharges a small droplet of ink from a nozzle can be exemplified. An example of the configuration of a recording head which is a main part of the recording apparatus is shown in FIG.

  The head includes an ink flow path 80 communicating with an ink chamber (not shown), an orifice plate 81 for ejecting ink droplets of a desired volume, a vibration plate 82 that directly applies pressure to ink, and the vibration plate 82. And a substrate 84 for indicating and fixing the orifice plate 81, the vibration plate 82, and the like.

  In FIG. 8, the ink flow path 80 is formed of a photosensitive resin or the like, the orifice plate 81 is formed with a discharge port 85 by electroforming or punching a metal such as stainless steel or nickel, and the diaphragm 82 is The piezoelectric element 83 is formed of a dielectric material such as barium titanate or PZT. The piezoelectric element 83 is formed of a metal film such as stainless steel, nickel, or titanium and a highly elastic resin film. The recording head configured as described above applies a pulsed voltage to the piezoelectric element 83 to generate strain stress, and the energy deforms the vibration plate 82 bonded to the piezoelectric element 83, so that the inside of the ink flow path 80. An operation is performed so as to perform recording by pressurizing the ink vertically and ejecting ink droplets (not shown) from the ejection port 85 of the orifice plate 81. Such a recording head is used by being incorporated in an ink jet recording apparatus similar to that shown in FIG. The detailed operation of the ink jet recording apparatus can be performed in the same manner as described above.

Hereinafter, the present invention will be described in detail based on examples. The present invention is not limited to these examples. In the text, “parts” and “%” are based on mass unless otherwise specified.
In the following examples, gel permeation chromatography (GPC, HLC-8220 manufactured by Tosoh Corporation) was used for molecular weight measurement, and a nuclear magnetic resonance absorption measurement apparatus (NMR, Bruker BioSpin Corporation) was used for copolymer identification. DPX400) was used.

[Example 1]
(Preparation of colored dispersion I)
C. is a commercially available oil-soluble dye as a water-insoluble colorant. I. 10.0 parts of Solvent Black 6 and 90.0 parts of tetrahydrofuran as a water-soluble organic solvent are mixed, and this mixture solution is mixed with a random styrene-maleic acid copolymer having a commercially available anionic group as a polymer dispersing agent. A tetrahydrofuran solution containing 10.0 parts of a polymer (number average molecular weight 10,000), stirred well so as to be uniformly dissolved by heating to 40 ° C., and containing a water-insoluble colorant and a polymer dispersant a was obtained. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 10 parts of ion-exchanged water was added to the tetrahydrofuran solution a. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution was 0.3 times the minimum water content ratio at which the used polymer dispersant was precipitated from the dissolved state. ... Second step Further, 90 parts of an aqueous sodium hydroxide solution containing sodium equivalent to the equivalent of the unneutralized anionic group of the polymer dispersant used is added to the solution obtained in the second step. did. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the target colored dispersion I was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Example 2]
(Preparation of colored dispersion II)
Tetrahydrofuran solution a was obtained in exactly the same manner as in Example 1. ... 1st process Then, 67 parts of ion-exchange water was added to the said tetrahydrofuran solution a. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution was 2.0 times the minimum water content ratio at which the used polymer dispersant was precipitated from the dissolved state. ... Second process

Furthermore, 33 parts of an aqueous sodium hydroxide solution containing sodium corresponding to the equivalent of the unneutralized anionic group of the polymer dispersant used was added to the solution obtained in the second step. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the target colored dispersion liquid II was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Example 3]
(Preparation of polymer dispersant A)
Synthesis of AB diblock copolymer consisting of hydrophobic block and hydrophilic block:
After the inside of the glass container fitted with the three-way cock was replaced with nitrogen, the adsorbed water was removed by heating at 250 ° C. in a nitrogen gas atmosphere. After returning the system to room temperature, 12 mmol of 2-decanoxyethyl vinyl ether, 16 mmol of ethyl acetate, 0.1 mmol of 1-isobutoxyethyl acetate, and 11 cm ³ of toluene were added, and the system temperature reached 0 ° C. By the way, 0.2 mmol of ethylaluminum sesquichloride was added to initiate polymerization, and the A component of the AB diblock copolymer was synthesized.

The molecular weight was monitored in a time-sharing manner using molecular sieve column chromatography (GPC), and after the polymerization of component A was completed, the carboxylic acid part of 4- (2-vinyloxyethoxy) benzoic acid (component B) was Synthesis was carried out by adding 12 mmol of vinyl monomer esterified with an ethyl group. The polymerization reaction was stopped by adding a 0.3% ammonia / methanol solution to the system, and the esterified carboxyl group was hydrolyzed with a sodium hydroxide / methanol solution to change to a carboxylic acid type. Diluted by adding dichloromethane to the mixed solution after the reaction, washed 3 times with 0.6N hydrochloric acid solution, then 3 times with distilled water, concentrated and dried with an evaporator, vacuum dried, and AB diblock A copolymer (polymer dispersant A) was obtained. The compound was identified using NMR and GPC (Mn = 3.5 × 10 ⁴ , Mn / Mw = 1.2).

(Preparation of colored dispersion III)
C. is a commercially available oil-soluble dye as a water-insoluble colorant. I. 10.0 parts of Solvent Yellow 82 and 90.0 parts of tetrahydrofuran as a water-soluble organic solvent are mixed. To this mixed solution is added 10.0 parts of the above polymer dispersant A as a polymer dispersant, and the mixture is heated to 40 ° C. The mixture was stirred well so as to dissolve evenly by heating to obtain a tetrahydrofuran solution b containing a water-insoluble colorant and a polymer dispersant. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 13 parts of ion-exchanged water was added to the tetrahydrofuran solution b. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution was 0.5 times the minimum water content ratio at which the used polymer dispersant was precipitated from the dissolved state. ... Second step Further, 87 parts of an aqueous sodium hydroxide solution containing sodium equivalent to the equivalent of the unneutralized anionic group of the polymer dispersant used is added to the solution obtained in the second step. did. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the target colored dispersion liquid III was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Example 4]
(Preparation of colored dispersion IV)
C. is a commercially available oil-soluble dye as a water-insoluble colorant. I. 10.0 parts of Solvent Red 132 and 90.0 parts of tetrahydrofuran as a water-soluble organic solvent were mixed. To this mixed solution, 10.0 parts of the polymer dispersant A used in Example 3 was added as a polymer dispersant. The solution was heated to 40 ° C. and stirred well so as to dissolve uniformly to obtain a tetrahydrofuran solution c containing a water-insoluble colorant and a polymer dispersant. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 38 parts of ion-exchanged water was added to the tetrahydrofuran solution c. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution was 1.5 times the minimum water content ratio at which the used polymer dispersant was precipitated from the dissolved state. ... 2nd process Furthermore, 62 parts of potassium hydroxide aqueous solution containing potassium corresponding to the equivalent of the non-neutralized anionic group which the used polymer dispersing agent has is added to the solution obtained at the said 2nd process. did. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... Third process

  Thereafter, tetrahydrofuran was removed by a rotary evaporator to obtain a target colored dispersion IV. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography. Tetrahydrofuran was the organic solvent content ratio in the organic solvent-water mixed solution, and the minimum organic solvent content ratio at which the water-insoluble colorant precipitated from the dissolved state. On the other hand, it was judged that 0.005 times the amount remained in the solution. ... Fourth process

[Example 5]
(Preparation of polymer dispersant B)
Synthesis of ABC triblock copolymer consisting of hydrophobic block and two hydrophilic blocks:
After the inside of the glass container fitted with the three-way cock was replaced with nitrogen, the adsorbed water was removed by heating at 250 ° C. in a nitrogen gas atmosphere. After returning the system to room temperature, 12 mmol of n-octadecyl vinyl ether, 16 mmol of ethyl acetate, 0.1 mmol of 1-isobutoxyethyl acetate, and 11 cm ³ of toluene were added, and when the system temperature reached 0 ° C., ethyl aluminum Polymerization was started by adding 0.2 mmol of sesquichloride, and the A component of the ABC triblock copolymer was synthesized.

The molecular weight was monitored in a time-sharing manner using molecular sieve column chromatography (GPC), and after the polymerization of component A was completed, 2- (2- (2- (2-methoxyethoxy) ethoxy) ethoxy) ethoxyvinyl ether ( Polymerization was continued by adding 24 mmol of component B). Similarly, the molecular weight was monitored by GPC, and after the polymerization of the B component was completed, 12 mmol of vinyl monomer obtained by esterifying the carboxylic acid part of 6- (2-vinyloxyethoxy) hexanoic acid (C component) with an ethyl group The synthesis was performed by adding The polymerization reaction was stopped by adding a 0.3% ammonia / methanol solution to the system, and the esterified carboxyl group was hydrolyzed with a sodium hydroxide / methanol solution to change to a carboxylic acid type. Thereafter, an ABC triblock copolymer (polymer dispersant B) was obtained in the same manner as in Example 3. The compound was identified using NMR and GPC (Mn = 3.7 × 10 ⁴ , Mn / Mw = 1.2).

(Preparation of colored dispersion V)
C. is a commercially available oil-soluble dye as a water-insoluble colorant. I. 10.0 parts of Solvent Blue 25, 100 parts of 1,4-dioxane as a water-soluble organic solvent, and 80.0 parts of acetone are mixed, and 10.0 parts of the polymer dispersant B as a polymer dispersant is added to this mixed solution. Was added and heated to 40 ° C. and stirred well so as to dissolve uniformly to obtain a 1,4-dioxane-acetone solution d containing a water-insoluble colorant and a polymer dispersant. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 110 parts of ion-exchanged water was added to the 1,4-dioxane-acetone solution d. At this time, the 1,4-dioxane-acetone solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-1,4-dioxane-acetone mixed solution was 2.0 times the minimum water content ratio at which the used water-insoluble colorant was precipitated from the dissolved state. ... 2nd process Furthermore, 90 parts of potassium hydroxide aqueous solution containing potassium corresponding to the equivalent of the non-neutralized anionic group which the used polymer dispersing agent has was added to the solution obtained at the said 2nd process. did. At this time, the water-1,4-dioxane-acetone mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, 1, 4- dioxane and acetone were removed with the rotary evaporator, and the target colored dispersion V was obtained. When the concentration of 1,4-dioxane and acetone in the solution at this time was analyzed by gas chromatography, 1,4-dioxane was an organic solvent content ratio in the organic solvent-water mixed solution, and the water-insoluble colorant was dissolved. The result was determined that 0.005 times the amount of the minimum organic solvent content precipitated from the state remained in the solution. ... Fourth process

[Example 6]
(Preparation of colored dispersion VI)
C. is a commercially available oil-soluble dye as a water-insoluble colorant. I. 10.0 parts of Solvent Red 218 and 180.0 parts of tetrahydrofuran as a water-soluble organic solvent were mixed, and 10.0 parts of the polymer dispersant B used in Example 5 was added as a polymer dispersant to the mixed solution. Then, the solution was heated to 40 ° C. and stirred well so as to be dissolved uniformly to obtain a tetrahydrofuran solution e containing a water-insoluble colorant and a polymer dispersant. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 23 parts of ion-exchanged water was added to the tetrahydrofuran solution e. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution was 0.3 times the minimum water content ratio at which the water-insoluble colorant used was precipitated from the dissolved state. ... Second step Further, 177 parts of an aqueous sodium hydroxide solution containing sodium corresponding to the equivalent of the unneutralized anionic group of the used polymer dispersant is added to the solution obtained in the second step. did. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the target colored dispersion VI was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Example 7]
(Preparation of colored dispersion VII)
C., which is a commercially available anionic dye. I. 10.0 parts of a water-insoluble colorant prepared using Direct Yellow 86 and the cationic compound benzyloctadecyldimethylammonium and 180.0 parts of tetrahydrofuran as a water-soluble organic solvent are mixed, and polymer dispersion is added to this mixed solution. 10.0 parts of polymer dispersant B used in Example 5 was added as an agent, heated to 40 ° C. and stirred well so as to dissolve uniformly, and contained a water-insoluble colorant and a polymer dispersant. A tetrahydrofuran solution f was obtained. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 90 parts of ion-exchanged water was added to the tetrahydrofuran solution f. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution is 1.8 times the minimum water content ratio in which the used polymer dispersant precipitates from the dissolved state, and the used water-insoluble colorant is in the dissolved state. It was 1.5 times with respect to the minimum water content ratio which precipitates from. ... Second step Further, 110 parts of an aqueous sodium hydroxide solution containing sodium corresponding to the equivalent of the unneutralized anionic group of the polymer dispersant used is added to the solution obtained in the second step. did. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the target colored dispersion liquid VII was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Example 8]
(Preparation of colored dispersion VIII)
C., which is a commercially available anionic dye. I. 10.0 parts of a water-insoluble colorant prepared using Direct Blue 199 and the cationic compound hexadecyltrimethylammonium and 180.0 parts of tetrahydrofuran as a water-soluble organic solvent are mixed, and polymer dispersion is added to this mixed solution. 10.0 parts of polymer dispersant B used in Example 5 was added as an agent, heated to 40 ° C. and stirred well so as to dissolve uniformly, and contained a water-insoluble colorant and a polymer dispersant. A tetrahydrofuran solution g was obtained. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 40 parts of ion-exchanged water was added to the tetrahydrofuran solution g. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution is 0.8 times the minimum water content ratio in which the used polymer dispersant precipitates from the dissolved state, and the used water-insoluble colorant is in the dissolved state. It was 0.5 times with respect to the minimum water content ratio which precipitates from. ... Second step Further, 160 parts of an aqueous sodium hydroxide solution containing sodium corresponding to the equivalent of the unneutralized anionic group of the used polymer dispersant is added to the solution obtained in the second step. did. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the target colored dispersion liquid VIII was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Example 9]
(Preparation of colored dispersion IX)
C. is a commercially available oil-soluble dye as a water-insoluble colorant. I. 10.0 parts of Solvent Red 49 and 180.0 parts of tetrahydrofuran as a water-soluble organic solvent are mixed, and 10.0 parts of the polymer dispersant B used in Example 5 is added as a polymer dispersant to the mixed solution. The solution was stirred well so that it was heated to 40 ° C. and uniformly dissolved to obtain a tetrahydrofuran solution h containing a water-insoluble colorant and a polymer dispersant. This solution was filtered with a filter having a pore size of 0.2 μm. However, no precipitate of coloring material or polymer dispersing agent was observed on the filter paper, and all the coloring material and polymer dispersing agent were completely dissolved. The result was expected. Further, the solubility of the used coloring material in water was examined, but it was not dissolved at all in water. ... First step

Next, 45 parts of ion-exchanged water was added to the tetrahydrofuran solution h. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. At this time, the water content ratio in the water-tetrahydrofuran mixed solution is 0.9 times the minimum water content ratio in which the used polymer dispersant precipitates from the dissolved state, and the used water-insoluble colorant is in the dissolved state. It was 0.6 times with respect to the minimum water content ratio which precipitates from. ... Second step Further, 155 parts of an aqueous sodium hydroxide solution containing sodium corresponding to the equivalent of the non-neutralized anionic group of the polymer dispersant used is added to the solution obtained in the second step. did. At this time, the water-tetrahydrofuran mixed solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the target colored dispersion liquid IX was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Comparative Example 1]
(Preparation of colored dispersion X)
A tetrahydrofuran solution was obtained in exactly the same manner as in Example 1. ... 1st process Then, 100 parts of sodium hydroxide aqueous solution containing sodium equivalent to the equivalent of the unneutralized anionic group which the used polymer dispersing agent has was added to the solution obtained at the said 1st process. did. At this time, the tetrahydrofuran solution phase was well stirred with a magnetic stirrer. ... 3rd process Then, tetrahydrofuran was removed with the rotary evaporator and the colored dispersion liquid X was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Comparative Example 2]
(Preparation of colored dispersion XI)
The procedure was carried out except that, instead of the polymer dispersant used in Example 1, a styrene-maleic acid random copolymer (number average molecular weight 10,000) neutralized with sodium was used as the polymer dispersant. A tetrahydrofuran solution was obtained in the same manner as in Example 1. ... 1st process Then, 100 parts of ion-exchange water was added to the said tetrahydrofuran solution. At this time, the aqueous phase was well stirred with a magnetic stirrer. ... 2nd process Then, tetrahydrofuran was removed with the rotary evaporator and colored dispersion liquid XI was obtained. The concentration of tetrahydrofuran in the solution at this time was analyzed by gas chromatography, but it was not detected, and the result was judged not to remain in the solution. ... Fourth process

[Comparative Example 3]
(Preparation of colored dispersion XII)
C., a commercially available oil-soluble dye. I. 10 parts of Solvent Red 132, 10 parts of the styrene-maleic acid random copolymer (number average molecular weight 10,000) used in Example 1, and an anionic hydrophilic group and an equivalent amount of sodium hydroxide in this polymer dispersant 100 parts of ion-exchanged water was mixed and stirred and mixed well so as to be uniformly dispersed by a bead mill disperser to obtain colored dispersion XII.

[Comparative Example 4]
(Preparation of colored dispersion XIII)
C., a commercially available pigment. I. 10 parts of Pigment Red 122, 10 parts of the styrene-maleic acid random copolymer (number average molecular weight 10,000) used in Example 1, and an anionic hydrophilic group and an equivalent amount of sodium hydroxide in the polymer dispersant 100 parts of ion-exchanged water was mixed and stirred and mixed well so as to be uniformly dispersed by a bead mill disperser to obtain colored dispersion XIII.

(Evaluation)
Table 1 evaluated the average particle diameter and dispersion stability of the colored dispersions of Examples 1 to 9 and the colored dispersions of Comparative Examples 1 to 4. As a result, as described in Table 1, the colored dispersions of all the examples had a smaller average particle diameter and better dispersion stability than the colored dispersions of the comparative examples.

* 1: Average particle diameter Each colored dispersion was measured with a particle size distribution measuring apparatus PAR-III (manufactured by Otsuka Electronics Co., Ltd.) using a laser scattering method, and the average particle diameter was calculated.

* 2: Dispersion stability After each colored dispersion is stored at 60 ° C for 1 month, it is treated for 8000 G1 hours with a centrifuge, and the absorption spectrum is measured for the concentration difference between the upper and lower parts of the colored dispersion. The evaluation was as follows.
A: Absorbance at the top of the colored dispersion after centrifugation / 95% or more at the bottom of the colored dispersion after centrifugation.
○: Absorbance at the top of the colored dispersion after centrifugation / absorbance at the bottom of the colored dispersion after centrifugation is 90% or more and less than 95%.
Δ: Absorbance at the upper part of the colored dispersion after centrifugation / absorbance at the lower part of the colored dispersion after centrifugation is from 80% to less than 90%.
X: Absorbance at the upper part of the colored dispersion after centrifugation / absorbance at the lower part of the colored dispersion after centrifugation is less than 80%.

以上の成分を混合し、充分攪拌して、目的のインク１を得た。 [Example 10]
(Preparation of ink 1)

The above components were mixed and sufficiently stirred to obtain the target ink 1.

[Examples 11 to 18 and Comparative Examples 5 to 8]
(Preparation of inks 2 to 13)
Instead of the colored dispersion I used in Example 10, the colored dispersion II is used in Example 11, the colored dispersion III is used in Example 12, the colored dispersion IV is used in Example 13, and the colored dispersion is used in Example 14. V, Example 15 colored dispersion VI, Example 16 colored dispersion VII, Example 17 colored dispersion VIII, Example 18 colored dispersion IX, and Comparative Example 5 colored dispersion. The target ink 2 was prepared in the same manner as in Example 10, except that X was used as the colored dispersion XI in Comparative Example 6, the colored dispersion XII was used in Comparative Example 7, and the colored dispersion XIII was used in Comparative Example 8. ~ 13 were obtained.

(Evaluation)
Inkjet recording apparatus BJF-660 having an on-demand type multi-recording head that ejects ink by applying thermal energy according to recording signals to the inks of Examples 10 to 18 and Comparative Examples 5 to 8 Each was mounted on Canon), printed on glossy paper SP101 (made by Canon), and evaluated in Table 2. As a result, as shown in Table 2, the inks of all the examples had better ejection stability and better image quality and color development characteristics than the comparative inks.

* 3: Ejection characteristics After each ink is stored at 60 ° C for 1 month, a 100% solid image is printed in an environment of 10% humidity at 5 ° C, and after resting for 1 minute, a 100% solid image is printed again. The obtained images were evaluated according to the following evaluation criteria.
(Double-circle): There is no white stripe and it is printed normally.
○: Slight white streaks are observed at the beginning of printing.
Δ: White streaks are observed in the entire image.
X: An image is hardly printed.

* 4: Image characteristics After each ink was stored at 60 ° C. for 1 month, a square pattern at 25 mm intervals was printed at 5 ° C. in an environment of 10% humidity, and the printed image was evaluated according to the following evaluation criteria.
(Double-circle): Even if it observes with a microscope, printing is not disturb | confused at all, and a square pattern is printed normally by 25 mm space | interval.
◯: When observed with a microscope, printing irregularities are partially observed, but square patterns are printed at intervals of 25 mm.
Δ: Printing disorder is partially observed even with the naked eye, and part of the square pattern is shifted from the 25 mm interval.
X: Disturbance of printing is seen with the naked eye as a whole, and the entire square pattern is shifted from the interval of 25 mm.

* 5: Color development characteristics The saturation and image density of the printed matter were visually determined.
○: High saturation and high image density.
Δ: Saturation is low or image density is low.
X: Low saturation and low image density.

  The present invention can produce a colored dispersion that can provide an image having good dispersion stability, high color development, and high fastness, and also has good discharge performance and excellent color development and fastness. Ink, an ink jet recording method, an ink cartridge, and an ink jet recording apparatus that can stably record an image at any time can be provided.

It is a flowchart figure of the manufacturing method of a colored dispersion liquid. It is a longitudinal cross-sectional view which shows an example of the head of an inkjet recording device. FIG. 3 is a cross-sectional view taken along line AB in FIG. 2. FIG. 3 is an external perspective view of a head in which the head shown in FIG. It is a schematic perspective view which shows an example of an inkjet recording device. It is a longitudinal cross-sectional view which shows an example of an ink cartridge. It is a perspective view which shows an example of a recording unit. It is a schematic sectional drawing which shows another structural example of an inkjet recording head.

Explanation of symbols

13: Head 14: Flow path (nozzle)
15: heating element substrate 16: protective layer 17-1, 17-2: electrode 18: heating resistor layer 19: heat storage layer 20: substrate 21: ink 22: discharge orifice (micropore)
23: Meniscus 24: Ink droplet 25: Recording material 26: Multi-nozzle 27: Glass plate 28: Heat generating head 40: Ink bag 42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed unit 52: Paper feed Roller 53: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Discharge recovery unit 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head unit 72: Air Communication port 80: Ink channel 81: Orifice plate 82: Vibration plate 83: Piezoelectric element 84: Substrate 85: Ejection port

Claims (16)

In a method for producing a colored dispersion mainly comprising a water-insoluble colorant, a polymer dispersant and water used for a recording ink,
(1) a first step of dissolving a water-insoluble colorant soluble in a water-soluble organic solvent and a polymer dispersant having an unneutralized anionic hydrophilic group in the water-soluble organic solvent;
(2) a second step of adding water to the solution prepared in the first step,
(3) a third step of adding an aqueous solution containing a neutralizing agent capable of neutralizing the polymer dispersant to the solution prepared in the second step;
(4) a fourth step for removing the organic solvent in the aqueous solution prepared in the third step;
A method for producing a colored dispersion characterized by comprising:   The amount of water added in the second step is the water content ratio (mass ratio) in the organic solvent-water mixed solution after the addition of water, and the minimum water content ratio (mass mass) at which the polymer dispersant precipitates from the dissolved state. The method for producing a colored dispersion according to claim 1, wherein the addition amount is adjusted so as to be in a range of 0.3 to 2.0 times the ratio.   The amount of water added in the second step is the water content ratio (mass ratio) in the organic solvent-water mixed solution after the addition of water, and the lowest water content ratio (mass mass) at which the water-insoluble colorant precipitates from the dissolved state. The method for producing a colored dispersion according to claim 1, wherein the addition amount is adjusted so as to be in a range of 0.3 to 2.0 times the ratio.   The method for producing a colored dispersion according to claim 1, wherein the water-soluble organic solvent is a cyclic ether.   The method for producing a colored dispersion according to claim 1, wherein the water-insoluble colorant is an oil-soluble dye.   The method for producing a colored dispersion according to claim 1, wherein the water-insoluble colorant is a colorant obtained by water-solubilizing an anionic dye with a cationic compound.   The method for producing a colored dispersion according to claim 1, wherein the neutralizing agent capable of neutralizing the polymer dispersant is an alkali metal compound.   The polymer dispersant is a block copolymer comprising at least one hydrophobic block and at least one hydrophilic block, and each block is a polymer dispersant composed of a vinyl ether monomer. A method for producing a colored dispersion as described in 1.   The hydrophilic block of the polymer dispersant includes at least a block composed of a vinyl ether monomer having a nonionic hydrophilic group and a block composed of a vinyl ether monomer having an anionic hydrophilic group. Of producing a colored dispersion liquid.   The polymer dispersant is composed of a block composed of a hydrophobic vinyl ether monomer, a block composed of a hydrophilic vinyl ether monomer having a nonionic hydrophilic group, and a hydrophilic vinyl ether monomer having an anionic hydrophilic group. The manufacturing method of the colored dispersion liquid of Claim 8 comprised at least by the order of the block.   An ink for inkjet recording mainly composed of a water-insoluble colorant, a polymer dispersant, a water-soluble organic solvent, and water, containing a colored dispersion produced by the production method according to any one of claims 1 to 10. An ink for ink jet recording characterized by the above.   In the ink jet recording method performed by applying energy to the ink and causing the ink to fly to be applied to a recording material, the color dispersion produced by the manufacturing method according to any one of claims 1 to 10. An ink jet recording method comprising a liquid.   The ink jet recording method according to claim 12, wherein the energy is thermal energy.   13. The ink jet recording method according to claim 12, wherein the recording material is a recording material having a coating layer for receiving ink on at least one surface.   An ink cartridge comprising an ink containing portion containing ink, wherein the ink contains a colored dispersion produced by the production method according to any one of claims 1 to 10. 11. The manufacturing method according to claim 1, wherein an ink cartridge includes an ink storage unit that stores ink, and an ink jet recording apparatus including a head unit for discharging the ink. An inkjet recording apparatus comprising the produced colored dispersion.

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