JP2010006874A - Water-insoluble coloring material dispersion and its production method, recording liquid, ink set, printed article, image formation method, and image formation device using the same - Google Patents

Abstract

〔環ＡはＮを含むヘテロ環基であり、該ヘテロ環基にさらに環構造基を有してもよい。〕
【選択図】なし[Problem] To provide a water-insoluble colorant dispersion in which primary particles of water-insoluble colorant particles are extremely fine, have high dispersion stability, have very high storage stability, and can be stored for a long time.
A water-insoluble colorant dispersion containing fine particles of a water-insoluble colorant, an aqueous medium, and a polymer compound, wherein the polymer compound has an acid group such as a carboxylic acid group or a sulfonic acid group. Polymer obtained by polymerizing a polymerizable compound having a hydrophilic part, a styrene polymerizable compound having a hydrophobic part even if having a substituent, and a styrene polymerizable compound represented by the following general formula (I) A water-insoluble colorant dispersion which is a compound.

[Ring A is a heterocyclic group containing N, and the heterocyclic group may further have a ring structure group. ]
[Selection figure] None

Description

  The present invention relates to a dispersion of a water-insoluble colorant and a method for producing the same, a recording liquid using the same, an ink set, a printed matter, an image forming method, and an image forming apparatus.

  The ink jet recording method is capable of high-speed recording, has a high degree of freedom in drawing patterns, and has low noise during recording. Further, there are advantages that image recording is possible at low cost and color recording is easy. Therefore, it is rapidly spreading and further developing today. Conventionally, a dye ink in which a water-soluble dye is dissolved in an aqueous medium has been widely used as the recording liquid. However, since the dye ink is inferior in water resistance and weather resistance of the printed matter, a pigment ink capable of improving this has been studied.

  Incidentally, the pigment ink is usually obtained by dispersing a water-insoluble pigment in an aqueous medium. In general, pigments, various surfactants, water-soluble polymers, etc. are used as dispersants, added alone or in combination to aqueous solvents, and pulverized using a dispersing machine such as a sand mill, bead mill, or ball mill. However, a method of reducing the pigment particle diameter is employed (see Patent Documents 1 and 2). In addition, it has been proposed to make a pigment into a solid solution in consideration of improvement in coloring power and weather resistance (see Patent Document 3). In addition, a method of preparing a pigment dispersion by mixing an organic pigment and a polymer dispersant, or a polymer compound as a dispersant in an aprotic organic solvent in the presence of an alkali, and then mixing this solution with water (Hereinafter, the above method will be referred to as a build-up method), and predetermined polymer compounds used therein have been studied (see Patent Documents 4 to 7). However, the pigment dispersions prepared by these methods are likely to increase in primary or secondary particle diameter during storage and cannot be said to have sufficient storage stability, and further improvement in storage stability has been desired.

JP 2006-57044 A JP 2006-328262 A JP-A-60-35055 JP 2003-26972 A JP 2004-43776 A JP 2006-342316 A JP 2007-119586 A

  In the present invention, the primary particles of the water-insoluble colorant fine particles are extremely fine, have high dispersion stability, and extremely high storage stability, so that the water-insoluble color can be stored for a long time while maintaining desired performance. It is an object of the present invention to provide a color material dispersion and a method for producing a water-insoluble color material dispersion which can be obtained efficiently. It is another object of the present invention to provide a recording liquid, an ink set, an image forming method, and an image forming apparatus using the water-insoluble colorant dispersion having the above excellent characteristics.

The above problems have been achieved by the following means.
(1) A water-insoluble colorant dispersion containing fine particles of a water-insoluble colorant, an aqueous medium, and a polymer compound, wherein the polymer compound comprises a carboxylic acid group, a sulfonic acid group, a phosphate group, and a hydroxyl group. A polymerizable compound that forms a hydrophilic site when polymerized with at least one acid group selected from the group consisting of: and a styrene polymerizable compound that forms a hydrophobic site when polymerized that may have a substituent And a styrene-polymerizable compound represented by the following general formula (I).

〔式（Ｉ）中、環Ａは窒素原子を含むヘテロ環基である。該ヘテロ環基Ａはさらに環置換基を有していてもよく、又は他の環と縮環してもいてもよい。〕
（２）さらに無機もしくは有機塩基を含有することを特徴とする（１）に記載の水不溶性色材分散体。
（３）上記無機もしくは有機塩基が、下記一般式（ＩＩ）又は（ＩＩＩ）で表される相間移動型塩基であることを特徴とする（２）に記載の水不溶性色材分散体。

[In Formula (I), Ring A is a heterocyclic group containing a nitrogen atom. The heterocyclic group A may further have a ring substituent, or may be condensed with another ring. ]
(2) The water-insoluble colorant dispersion according to (1), further containing an inorganic or organic base.
(3) The water-insoluble colorant dispersion according to (2), wherein the inorganic or organic base is a phase transfer base represented by the following general formula (II) or (III).

〔式（ＩＩ）及び（ＩＩＩ）中Ｒ_１〜Ｒ_５はそれぞれ独立に、炭素原子数１〜１０のアルキル基、アルコキシ基、アリール基、又はアルキルアリール基である。ｎは１〜４の整数である。〕
（４）前記酸基がカルボン酸基であることを特徴とする（１）〜（３）のいずれか１項に記載の水不溶性色材分散体。
（５）前記水不溶性色材が、キナクリドン有機顔料、ジケトピロロピロール有機顔料、及びモノアゾイエロー有機顔料からなる群より選ばれる有機顔料であることを特徴とする（１）〜（４）のいずれか１項に記載の水不溶性色材分散体。
（６）無機もしくは有機塩基の存在下で有機溶剤に高分子化合物と水不溶性色材とを共溶解させ、その溶解液を水性媒体と混合し、前記水不溶性色材の微粒子を生成させる水不溶性色材分散体の製造方法であって、前記高分子化合物が、カルボン酸基、スルホン酸基、リン酸基、及び水酸基からなる群より選ばれる一種類以上の酸基をもつ重合したときに親水性部位をなす重合性化合物と、置換基を有してもよい重合したときに疎水性部位をなすスチレン重合性化合物と、下記一般式（Ｉ）で表されるスチレン重合性化合物とを重合させてなることを特徴とする水不溶性色材分散体の製造方法。

[In formulas (II) and (III), R _{1 to} R ₅ are each independently an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an aryl group, or an alkylaryl group. n is an integer of 1-4. ]
(4) The water-insoluble colorant dispersion described in any one of (1) to (3), wherein the acid group is a carboxylic acid group.
(5) The water-insoluble colorant is an organic pigment selected from the group consisting of quinacridone organic pigments, diketopyrrolopyrrole organic pigments, and monoazo yellow organic pigments, any one of (1) to (4) 2. The water-insoluble colorant dispersion according to item 1.
(6) A water-insoluble solution in which a polymer compound and a water-insoluble colorant are co-dissolved in an organic solvent in the presence of an inorganic or organic base, and the solution is mixed with an aqueous medium to form fine particles of the water-insoluble colorant. A method for producing a colorant dispersion, wherein the polymer compound is hydrophilic when polymerized with one or more acid groups selected from the group consisting of carboxylic acid groups, sulfonic acid groups, phosphoric acid groups, and hydroxyl groups. A polymerizable compound that forms an ionic moiety, a styrene polymerizable compound that forms a hydrophobic moiety when polymerized, which may have a substituent, and a styrene polymerizable compound represented by the following general formula (I) A method for producing a water-insoluble colorant dispersion, characterized by comprising:

〔式（Ｉ）中、環Ａは窒素原子を含むヘテロ環基である。該ヘテロ環基Ａはさらに環置換基を有していてもよく、又は他の環と縮環してもいてもよい。〕
（７）前記水不溶性色材が、キナクリドン有機顔料、ジケトピロロピロール有機顔料、及びモノアゾイエロー有機顔料からなる郡より選ばれる有機顔料であることを特徴とする（６）に記載の水不溶性色材分散体の製造方法。
（８）（６）又は（７）に記載の製造方法で得た、前記水不溶性色材の微粒子、前記水性媒体、及び前記高分子化合物を含有する水不溶性色材分散体。
（９）（１）〜（５）及び（８）のいずれか１項に記載の水不溶性色材分散体中の水不溶性色材の微粒子を、記録液全質量の０．１〜１５質量％含むことを特徴とする記録液。
（１０）前記記録液がインクジェット用記録液である（９に記載の記録液。
（１１）（１０）に記載のインクジェット用記録液を用いたインクセット。
（１２）（９）もしくは（１０）に記載の記録液、又は（１１）に記載のインクセットを用いて記録液を媒体に付与する手段により画像が記録された印画物であって、前記手段が記録液の付与量もしくは濃度を調整する機能を有し、該手段により印画物の濃淡が調整された印画物。
（１３）（９）もしくは（１０）に記載の記録液、又は（１１）に記載のインクセットを用いて記録液を媒体に付与することにより、画像を記録する工程を有することを特徴とする画像形成方法。
（１４）（９）もしくは（１０）に記載の記録液、又は（１１）に記載のインクセットを用いて記録液を媒体に付与することにより、画像を記録させるための手段を有することを特徴とする画像形成装置。

[In Formula (I), Ring A is a heterocyclic group containing a nitrogen atom. The heterocyclic group A may further have a ring substituent, or may be condensed with another ring. ]
(7) The water-insoluble colorant according to (6), wherein the water-insoluble colorant is an organic pigment selected from the group consisting of a quinacridone organic pigment, a diketopyrrolopyrrole organic pigment, and a monoazo yellow organic pigment. Manufacturing method of material dispersion.
(8) A water-insoluble colorant dispersion containing fine particles of the water-insoluble colorant, the aqueous medium, and the polymer compound obtained by the production method according to (6) or (7).
(9) The water-insoluble colorant fine particles in the water-insoluble colorant dispersion described in any one of (1) to (5) and (8) are 0.1 to 15% by mass of the total mass of the recording liquid. A recording liquid comprising:
(10) The recording liquid is an inkjet recording liquid (the recording liquid according to 9).
(11) An ink set using the inkjet recording liquid according to (10).
(12) A printed matter in which an image is recorded by means of applying the recording liquid to the medium using the recording liquid according to (9) or (10) or the ink set according to (11), Has a function of adjusting the application amount or density of the recording liquid, and the printed matter in which the density of the printed matter is adjusted by the means.
(13) A step of recording an image by applying the recording liquid to the medium using the recording liquid according to (9) or (10) or the ink set according to (11). Image forming method.
(14) A recording liquid described in (9) or (10) or an ink set described in (11) is used to apply a recording liquid to a medium, thereby having means for recording an image. An image forming apparatus.

  The water-insoluble colorant dispersion of the present invention has the desired performance over a long period of time because the primary particles of the water-insoluble colorant fine particles in the dispersion are extremely fine, the dispersion stability is high, and the storage stability is very high. Storage is possible. Further, according to the production method of the present invention, a dispersion of a water-insoluble colorant having the above-described excellent characteristics can be obtained efficiently. Furthermore, according to the recording liquid, the ink set, the image forming method, and the image forming apparatus using the water-insoluble colorant dispersion, it is possible to accurately form an image with excellent ink ejection properties and high transparency.

Hereinafter, the water-insoluble colorant dispersion of the present invention will be described in detail based on preferred embodiments thereof.
First, a polymer compound having a heterocyclic group and having an acid group used in the present invention (hereinafter, sometimes referred to as “acid group-containing polymer compound having a heterocyclic group” or simply “specific polymer compound”). .)), The precursor constituting this, that is, each polymerizable compound before the polymerization will be described.

In the present invention, as the polymerizable compound, a polymerizable compound (polymerizable compound [i]) that has an acid group and then forms a hydrophilic portion (a repeating unit having a hydrophilic group) after polymerization is used. Specifically, acrylic acid, acrylic acid derivative, methacrylic acid, methacrylic acid derivative, maleic acid, maleic acid derivative, alkenyl sulfonic acid, itaconic acid, itaconic acid derivative, fumaric acid, fumaric acid derivative, vinylphosphonic acid, phenol and And derivatives thereof. However, the acid group in the present invention is not limited to this, and general functional groups that can be ionized and ionized in water by sodium hydroxide or potassium hydroxide, which are generally used as strong bases, are used as acid groups. May be.
The acid group is more preferably a carboxylic acid group or a sulfonic acid group, and even more preferably a carboxylic acid group. Furthermore, the more preferable range of the acid value of the acid group-containing polymer compound having the heterocyclic structure of the present invention is 100 mgKOH / g to 300 mgKOH / g, and more preferably 140 mgKOH / g to 240 mgKOH / g.

  As the polymerizable compound that forms the specific polymer compound used in the water-insoluble colorant dispersion of the present invention, it may further have a substituent, and after polymerization, a hydrophobic site (has no hydrophilic group) A styrene polymerizable compound (polymerizable compound [ii]) forming a repeating unit) is used. Specific examples include styrene, α-methylstyrene and derivatives thereof, vinyl naphthalene, and vinyl naphthalene derivatives. Although there is no particular limitation as a substituent, it is a non-hydrophilic group, that is, a group of functional groups having low hydrogen bonding properties. Specifically, an alkyl group, an alkoxy group, an alkyl ketone group, an alkoxycarbonyl group, a cyano group, an aryl group. And an alkylaryl group.

As the polymerizable compound forming the specific polymer compound used in the water-insoluble colorant dispersion of the present invention, a styrene polymerizable compound (polymerizable compound [iii]) represented by the general formula (I) is further added. Use.
The heterocyclic group A in the general formula (I) has a nitrogen atom in addition to a carbon atom, but may further have an oxygen atom and / or a sulfur atom. The heterocyclic group A is preferably a 4- to 7-membered ring, more preferably a 5-membered ring or a 6-membered ring. Further, the heterocyclic group A may have a substituent, and another ring (for example, cycloalkyl, aryl group, heteroaryl group) may be condensed.

  Specific examples of the heterocyclic group A include carbazole, acridone, imidazole, benzimidazole, pyrrole, indole, benzoxazole, benzothioxazole, and phthalimide.

  The acid group-containing polymer compound having a heterocyclic group used in the dispersion of the present invention is a copolymer obtained by polymerizing the above three kinds of polymerizable compounds [i] to [iii]. However, in addition to these polymerizable compounds, various hydrophilic monomer components, hydrophobic monomer components, and the like can be used as copolymerization components. Thus, by introducing another copolymerizable component, various hydrophilicity / hydrophobicity / other physical properties can be imparted to the specific polymer compound as well as the combination of the three polymerizable compounds. It is preferable that the other components can be adjusted by changing the type and amount of the other components. The polymerization ratio of each polymerizable compound in the acid group-containing polymer compound having a heterocyclic group is not particularly limited, but the composition ratio n of the repeating unit formed by the polymerizable compound [i] is 10 to 50 (mass composition ratio). It is preferable that it is 20-40 (mass composition ratio). The composition ratio 1 of the repeating units formed by the polymerizable compound [ii] is preferably 20 to 60 (mass composition ratio), and more preferably 30 to 50 (mass composition ratio). The composition ratio m of the repeating unit formed by the polymerizable compound [iii] is preferably 0 to 75 (mass composition ratio), more preferably 5 to 45 (mass composition ratio), and 5 to 25 (mass composition). Ratio) is particularly preferred.

  It is not clear why the acid group-containing polymer compound having a heterocyclic group enhances the dispersion stability of the water-insoluble colorant fine particles in the dispersion and further improves the storage stability. Including presumption, when the polymer compound functions as a dispersant, the solubility of the polymer compound in the dispersion is reduced in relation to the aqueous medium, and the adsorption force is increased due to the precipitation on the surface of the fine particles. Increase. Alternatively, it is conceivable that particle formation is performed while the heterocyclic structure portion of the specific polymer compound is taken into the fine particles, and the adsorption force is increased due to the influence. That is, since the specific polymer compound has a specific adsorption state on the surface of the fine particles, the polymer compound interacts with the aqueous medium or the water-insoluble colorant in the dispersion, and the dispersion stability and storage are extremely high. Stability is expected to be realized.

  For example, the hydrophobic monomer component includes a monomer component having a hydrophobic unit such as a long-chain alkyl group having 8 or more carbon atoms, a t-butyl group, a phenyl group, a biphenyl group, or a naphthyl group as a structural unit. From the viewpoint of imparting high dispersion stability to the water-insoluble colorant, a block segment having stearyl methacrylamide or the like as a repeating unit as a hydrophobic monomer is preferred, but the hydrophobic monomer component is not limited thereto.

  Examples of the hydrophilic monomer component include acrylic acid ester / methacrylic acid ester having an alkylene oxide group, N-vinylpyrrolidone, N-vinylimidazole, and the like, but the hydrophilic monomer component of the present invention is limited to this. It is not a thing.

The amount of the specific polymer compound contained in the dispersion of the present invention is not particularly limited, but is preferably 10 to 100 parts by mass with respect to 100 parts by mass of the water-insoluble colorant, and 20 to 50 parts by mass. It is more preferable.
Although the molecular weight of the polymer compound is not particularly limited, the mass average molecular weight is preferably 5,000 to 100,000, and more preferably 10,000 to 50,000. In the present invention, the term “molecular weight” means a weight average molecular weight, and the weight average molecular weight is an average molecular weight in terms of polystyrene measured by gel permeation chromatography (carrier: tetrahydrofuran) unless otherwise specified.

  In the present invention, the “dispersion” refers to a composition in which predetermined fine particles are dispersed in a medium, and the form thereof is not particularly limited, and is a liquid composition (dispersion), a paste-like composition, and a solid form. It is used in the meaning including the composition. Moreover, the said specific high molecular compound can be used as a dispersing agent individually by 1 type or in combination of 2 or more types. In the dispersion of the present invention, even if the specific polymer compound is contained in the water-insoluble colorant fine particles, the specific polymer compound coexists in the dispersion separately from the fine particles. May be. Alternatively, the contained form may be such that a part of the specific polymer compound is adsorbed on the fine particles and is in a dissociation equilibrium state. The same applies to components other than the polymer compound, for example, a phase transfer base described later.

  As the acid group-containing polymer compound having a heterocyclic group used in the present invention, a particularly preferred general formula structure is shown below.

式中、Ｒ_１０１〜Ｒ_１０３は水素またはメチル基である。Ｒ_１０４〜Ｒ_１１８は置換もしくは非置換のアルキル、アルコキシ、ハロゲン、ヒドロキシ、チオアルコキシ、エステル、アミド、ケトン、シアノ、アリール、ヘテロアリールであり、各々でそれぞれ互いに結合し脂肪族性または芳香族性の環を形成することができる。
ＹはＯ、Ｓ、−（Ｃ＝Ｏ）−、ＮＲ_１１９を表し、Ｒ_１１９は水素、置換または非置換のアルキル、アルコキシ、アリール、ヘテロアリール基である。
Ｚは、置換基を有してもよいヘテロ環基を示し、置換基としてはアルキル、アルコキシ、ケトン、ハロゲン、ヒドロキシ、チオアルコキシ、エステル、アミド、ケトン、シアノ、アリール、ヘテロアリール基のいずれかを有し、あるいは縮環して構成される。
ｌ、ｍ、ｎは高分子の質量組成比を表し、ｌ＋ｍ＋ｎ＝１００となる範囲で任意に選択可能である。ｌ，ｍ，ｎの好ましい範囲は先に述べたものと同様である。

In the formula, R _{101 to} R ₁₀₃ are hydrogen or a methyl group. R _{104 to} R ₁₁₈ are substituted or unsubstituted alkyl, alkoxy, halogen, hydroxy, thioalkoxy, ester, amide, ketone, cyano, aryl, and heteroaryl, each bonded to each other to be aliphatic or aromatic Can be formed.
Y represents O, S, — (C═O) —, NR ₁₁₉ , and R ₁₁₉ is hydrogen, a substituted or unsubstituted alkyl, alkoxy, aryl, or heteroaryl group.
Z represents a heterocyclic group which may have a substituent, and the substituent is any of alkyl, alkoxy, ketone, halogen, hydroxy, thioalkoxy, ester, amide, ketone, cyano, aryl, heteroaryl group Or a condensed ring.
l, m, and n represent the mass composition ratio of the polymer, and can be arbitrarily selected within a range of l + m + n = 100. The preferable ranges of l, m, and n are the same as those described above.

  Next, the following exemplary compounds (D-1) to (D-20) are shown as acid group-containing polymer compounds having a heterocyclic structure having a preferred structure, but the present invention is not limited to these. . In the formula, Hex represents a hexyl group, and Bn represents a phenyl group.

  The water-insoluble colorant dispersion of the present invention may further contain an inorganic or organic base. This inorganic or organic base is preferably a phase transfer base, and specific examples include alkylammonium derivatives, alkylsulfonium derivatives, and alkylphosphonium derivatives. As the phase transfer type base, one having a structure in which the ClogP value is negative is preferable, and more preferable is negative than −2. Here, the ClogP value refers to a common logarithm value of 1-octanol / water partition coefficient P indicating the ratio between the equilibrium concentrations of the compound in 1-octanol and in water. This ClogP value is determined by a fragment approach based on the chemical structure of the compound (A. Leo, Comprehensive Medical Chemistry, Vol. 4; C. Hansch, P. G. Sammens, J. B. Taylor and C. A. Ramden. , P. 295, Pergramon Press, 1990), etc., and can be defined by values calculated with the “CLOGP” program available from Daylight Chemical Information Systems.

  As the phase transfer base, those represented by the general formula (II) or (III) are preferable. Particularly preferred are choline hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and the like, but the phase transfer base used in the present invention is not limited thereto.

  The proportion of the inorganic or organic base used is not particularly limited, but is preferably 1.0 to 100 molar equivalents, and 1.5 to 50 molar equivalents in terms of a molar ratio with the water-insoluble colorant. Is more preferable, and 2.0 to 20 molar equivalent is particularly preferable. The specific polymer compound in the water-insoluble colorant dispersion is preferably 0.5 to 10 molar equivalents relative to 1 molar equivalent of the acid group of the polymer. 0.8 It is more preferably ˜5 molar equivalents, and particularly preferably 0.9 to 1.5 molar equivalents.

  The organic pigment that can be used as the water-insoluble colorant in the dispersion of the present invention is not particularly limited in terms of hue or structure, and examples thereof include perylene compound pigments, perinone compound pigments, quinacridone compound pigments, and quinacridone quinone compound pigments. , Anthraquinone compound pigment, anthanthrone compound pigment, benzimidazolone compound pigment, disazo condensation compound pigment, disazo compound pigment, azo compound pigment, indanthrone compound pigment, indanthrene compound pigment, quinophthalone compound pigment, quinoxaline dione compound pigment, metal Complex azo compound pigment, phthalocyanine compound pigment, triarylcarbonium compound pigment, dioxazine compound pigment, aminoanthraquinone compound pigment, diketopyrrolopyrrole compound pigment, naphthol AS Compound pigments, thioindigo compound pigments, isoindoline compound pigments, isoindolinone compound pigments, pyranthrone compound pigments, isoviolanthrone compound pigment, or a mixture thereof.

  More specifically, for example, C.I. I. Pigment red 179, C.I. I. Pigment red 190, C.I. I. Pigment red 224, C.I. I. Perylene compound pigments such as C.I. Pigment Violet 29; I. Pigment orange 43, or C.I. I. Perinone compound pigments such as CI Pigment Red 194; I. Pigment violet 19, C.I. I. Pigment violet 42, C.I. I. Pigment red 122, C.I. I. Pigment red 192, C.I. I. Pigment red 202, C.I. I. Pigment red 207 or C.I. I. Pigment Red 209 quinacridone compound pigment, C.I. I. Pigment red 206, C.I. I. Pigment orange 48, or C.I. I. Quinacridonequinone compound pigments such as C.I. Pigment Orange 49; I. Anthraquinone compound pigments such as C.I. Pigment Yellow 147; I. Anthanthrone compound pigments such as C.I. Pigment Red 168; I. Pigment brown 25, C.I. I. Pigment violet 32, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment orange 36, C.I. I. Pigment orange 62, or C.I. I. Benzimidazolone compound pigments such as CI Pigment Red 185; I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 128), C.I. I. Pigment yellow 166, C.I. I. Pigment orange 34, C.I. I. Pigment orange 13, C.I. I. Pigment orange 31, C.I. I. Pigment red 144 (C.I. No. 20735), C.I. I. Pigment red 166, C.I. I. Pigment yellow 219, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. Pigment red 242, C.I. I. Pigment red 248, C.I. I. Pigment red 262, or C.I. I. Disazo condensation compound pigments such as C.I. Pigment Brown 23; I. Pigment yellow 13, C.I. I. Pigment yellow 83, or C.I. I. Disazo compound pigments such as C.I. Pigment Yellow 188; I. Pigment red 187, C.I. I. Pigment red 170, C.I. I. Pigment yellow 74, C.I. I. Pigment red 48, C.I. I. Pigment red 53, C.I. I. Pigment orange 64, or C.I. I. Azo compound pigments such as C.I. Pigment Red 247; I. Indanthrone compound pigments such as C.I. Pigment Blue 60; I. Indanthrene compound pigments such as C.I. Pigment Blue 60; I. Quinophthalone compound pigments such as C.I. Pigment Yellow 138; I. Quinoxalinedione compound pigments such as CI Pigment Yellow 213; I. Pigment yellow 129, or C.I. I. Pigment Yellow 150 and other metal complex azo compound pigments, C.I. I. Pigment green 7, C.I. I. Pigment green 36, C.I. I. Pigment green 37, C.I. I. Pigment blue 16, C.I. I. Pigment blue 75, or C.I. I. Phthalocyanine compound pigments such as C.I. Pigment Blue 15 (including 15: 1, 15: 6, etc.); I. Pigment blue 56 or C.I. I. Triarylcarbonium compound pigments such as C.I. Pigment Blue 61; I. Pigment violet 23, or C.I. I. Dioxazine compound pigments such as C.I. Pigment Violet 37; I. Aminoanthraquinone compound pigments such as C.I. Pigment Red 177; I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. Pigment red 272, C.I. I. Pigment orange 71, or C.I. I. Diketopyrrolopyrrole compound pigments such as C.I. Pigment Orange 73; I. Pigment red 187, or C.I. I. Naphthol AS compound pigments such as C.I. Pigment Red 170; I. Thioindigo compound pigments such as CI Pigment Red 88; I. Pigment yellow 139, C.I. I. Pigment Orange 66 and other isoindoline compound pigments, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, or C.I. I. Pigment Orange 61 and other isoindolinone compound pigments, C.I. I. Pigment orange 40, or C.I. I. A pyranthrone compound pigment such as C.I. Pigment Red 216; I. And isoviolanthrone compound pigments such as CI Pigment Violet 31.

  Of these, the water-insoluble colorant is preferably a quinacridone organic pigment, a diketopyrrolopyrrole organic pigment, or a monoazo yellow organic pigment.

  In the dispersion of the present invention, the content of the water-insoluble colorant in the dispersion is not particularly limited, and is preferably, for example, 0.01 to 30% by mass when considering use as an ink. More preferably, it is -20 mass%, and it is especially preferable that it is 1.1-15%. In addition, the water-insoluble colorant dispersion of the present invention contains an aqueous medium, and the content of the water-insoluble colorant dispersion is 0.01 to 30% by mass when considering use as an ink, for example. It is preferably 1.1 to 15% by mass.

  The dispersion in the present invention can maintain the dispersion at a low viscosity even at a high concentration. For example, when used as a recording liquid, the dispersion of the present invention is preferably used as a recording liquid because the degree of freedom of the types and amounts of additives that can be used in the recording liquid increases even if the concentration is low. Can do.

  A water-insoluble colorant dispersion of the present invention is obtained by co-dissolving a water-insoluble colorant and an acid group-containing polymer compound having a heterocyclic group in an organic solvent in the presence of an inorganic or organic base, , Sometimes referred to as a “water-insoluble colorant solution”) and an aqueous medium to produce the water-insoluble colorant fine particles.

  As the organic solvent used in the production method of the present invention, any kind of an aprotic organic solvent and a protic organic solvent can be used. However, the organic solvent for dissolving the water-insoluble colorant and the polymer compound in the presence of alkali is preferably an aprotic organic solvent, more preferably dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, sulfolane, etc. It is. Moreover, these can be used individually by 1 type or in combination of 2 or more types.

  The content of the organic solvent in the water-insoluble colorant solution is not particularly limited. However, when the water-insoluble colorant is in a better dissolved state, 2 to 500 parts by mass with respect to 1 part by mass of the water-insoluble colorant. Furthermore, it is preferable to use in the range of 5 to 100 parts by mass.

  In order to further improve the uniform dispersibility and storage stability of the dispersion, the amount of the acid group-containing polymer compound having a heterocyclic group contained in the solution obtained by co-dissolution with the water-insoluble colorant is as follows: It is preferably in the range of 0.1 to 1000 parts by mass, more preferably in the range of 1 to 500 parts by mass, and in the range of 10 to 250 parts by mass with respect to 100 parts by mass of the water-insoluble colorant. Particularly preferred.

  In the method for producing a water-insoluble colorant dispersion of the present invention, a solution in which a water-insoluble colorant or the like is dissolved is mixed with an aqueous medium. In the present invention, the aqueous medium is water alone or a mixed solvent of water-soluble organic solvents. At this time, the addition of the organic solvent is preferably used when water alone is insufficient to keep the pigment and the dispersant in a uniform dispersed state, or for acceleration of the aggregate dispersion process with a base. Specific examples of organic solvents that can be used include, but are not limited to, lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol, acetone, methyl ethyl ketone, and methyl isobutyl ketone. , Aliphatic ketones such as diacetone alcohol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, propylene glycol, ethylene glycol monomethyl or monoethyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, ethylene Glycol phenyl ether, propylene glycol phenyl ether, diethylene glycol monomethyl or Bruno ethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl or monoethyl ether, N- methylpyrrolidone, 2-pyrrolidone, dimethylformamide, dimethylimidazolidinone, dimethyl sulfoxide, dimethyl acetamide and the like. These can be used alone or in combination of two or more. Further, the amount of water in the water-insoluble colorant dispersion is preferably 99 to 20% by mass, more preferably 95 to 30% by mass. The amount of the water-soluble organic solvent in the dispersion is preferably 50 to 0.1% by mass, more preferably 30 to 0.05% by mass.

  In the production method of the present invention, the water-insoluble colorant is dissolved in an organic solvent together with the specific polymer compound. In addition to this, the organic solvent contains a crystal growth inhibitor, an ultraviolet absorber, an antioxidant, a resin. At least one of additives, surfactants and the like can be added as necessary.

  Examples of the crystal growth inhibitor include phthalocyanine derivatives and quinacridone derivatives that are well known in the art. For example, phthalocyanine phthalimidomethyl derivatives, phthalocyanine sulfonic acid derivatives, phthalocyanine N- (dialkylamino) methyl derivatives, phthalocyanines N- (dialkylaminoalkyl) sulfonic acid amide derivatives, phthalimidomethyl derivatives of quinacridone, sulfonic acid derivatives of quinacridone, N- (dialkylamino) methyl derivatives of quinacridone, N- (dialkylaminoalkyl) sulfonic acid amide derivatives of quinacridone, etc. Is mentioned.

  UV absorbers include metal oxides, aminobenzoate UV absorbers, salicylate UV absorbers, benzophenone UV absorbers, benzotriazole UV absorbers, cinnamate UV absorbers, nickel chelate UV absorbers, hindered amines. UV absorbers such as UV absorbers, urocanic acid UV absorbers and vitamin UV absorbers.

  Examples of the antioxidant include hindered phenol compounds, thioalkanoic acid ester compounds, organic phosphorus compounds, and aromatic amines.

  Examples of the resin additive include anion-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, polyurethane, carboxymethylcellulose, polyester, polyallylamine, polyvinylpyrrolidone, polyethyleneimine, polyaminesulfone, polyvinylamine, hydroxyethylcellulose, hydroxypropylcellulose, melamine resin, or these resins. Examples include synthetic resins such as modified products. These crystal growth inhibitors, ultraviolet absorbers, and resin additives can be used alone or in combination of two or more.

  Surfactants include alkyl benzene sulfonates, alkyl naphthalene sulfonates, higher fatty acid salts, higher fatty acid ester sulfonates, higher alcohol ether sulfates, higher alcohol ether sulfonates, higher alkyl sulfonamides. Anionic surfactants such as alkyl carboxylates and alkyl phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, ethylene oxide adducts of acetylene glycol, ethylene of glycerin Nonionic surfactants such as oxide adducts and polyoxyethylene sorbitan fatty acid esters, as well as amphoteric surfactants such as alkylbetaines and amidebetaines, Recon surfactant, including such fluorine-based surfactant, can be appropriately selected from surfactants and derivatives thereof are known.

  In the production method of the present invention, a water-insoluble colorant solution is mixed with an aqueous medium to produce water-insoluble colorant particles. The proportion of water used at this time further improves the dispersion stability of the particles. In addition, from the viewpoint of further improving the color density of the dispersion, 0.5 to 1000 parts by mass is preferable and 1 to 100 parts by mass is more preferable with respect to 1 part by mass of the water-insoluble colorant solution.

  In the production method of the present invention, the temperature when mixing the water-insoluble colorant pigment solution and the aqueous medium is preferably in the range of −50 ° C. to 100 ° C., and is adjusted in the range of −20 ° C. to 50 ° C. It is more preferable. The temperature of the solution at the time of mixing may greatly affect the size of the fine particles of the water-insoluble colorant to be generated, and the liquid temperature is −50 ° C. to 100 ° C. in order to obtain a dispersion of fine particles of nanometer order. It is preferable to make it into a range. At this time, a known freezing point depressant such as ethylene glycol, propylene glycol or glycerin can be added to the water to be mixed in order to ensure the fluidity of the liquid.

  Furthermore, in order to obtain nanometer-order fine particles having uniformity in size, it is preferable to mix the water-insoluble colorant solution and the aqueous medium as quickly as possible. Any of the devices used for stirring, mixing, dispersion, and crystallization, such as a circulation type stirring device, an external circulation type stirring device, a flow rate and an ion concentration control device, can be used. Moreover, you may mix in the water which flows continuously. As a method for adding the water-insoluble coloring material solution to the aqueous medium, any of the usual liquid injection methods can be used. preferable. In addition, in order to throw in in a short time, it can also throw in from several nozzles. Furthermore, in order to stably prepare an aqueous dispersion of water-insoluble colorant fine particles, an additive such as an alkali and a dispersant can be added to an aqueous medium to be mixed with the water-insoluble colorant solution.

  A water-insoluble colorant such as a pigment dissolved in an organic solvent is considered to form rapid crystal growth or an amorphous-like aggregate by mixing with an aqueous medium. In the present invention, the water-insoluble colorant coexists in a solution in which the acid group-containing polymer compound having the heterocyclic structure is co-dissolved, and the water-insoluble colorant is present during and immediately after the mixing step of the solution and the aqueous medium. Therefore, it is considered that high dispersion stability of the fine particles is realized. At this time, the heat treatment can be performed to adjust the crystal form and the aggregation state in the fine particle dispersion.

The aqueous water-insoluble colorant dispersion of the present invention can be used for various uses, for example, ink jet ink, as it is or by adjusting the colorant concentration as necessary.
In order to apply a conventional aqueous dispersion to an inkjet ink, the color material concentration may be low. Although the concentration can be increased by concentrating the dispersion medium of the dispersion, it is not practical industrially. On the other hand, the dispersion of the present invention can first take out the water-insoluble fine particles as a powder or paste and then impart water-dispersibility so that the water-insoluble fine particles can be efficiently redispersed in an aqueous medium. Therefore, an aqueous dispersion having a desired color material concentration can be efficiently prepared.

In the present invention, it is preferable to use the aqueous water-insoluble colorant dispersion obtained in the above-described process and further form an aggregate of fine particles of the water-insoluble colorant contained in the dispersion.
In the present invention, the term “fine particles of a water-insoluble colorant” includes fine particles composed only of a water-insoluble colorant and fine particles formed by a water-insoluble colorant and other components. For example, a water-insoluble colorant and / or other compound may form a fine particle by adsorbing so that the core of the particle is coated with the dispersant (polymer compound, surfactant, etc.). In the dispersion of the present invention, it is particularly preferable that the specific polymer compound is coated and adsorbed on the fine particles of the water-insoluble colorant. This coating adsorption state can be confirmed by, for example, X-ray crystal structure analysis (XRD).

  For the formation of the agglomerates of fine particles of the water-insoluble colorant, a treatment by adding an organic acid / inorganic acid is preferably used. The treatment using an acid preferably includes a step of agglomerating fine particles of a water-insoluble colorant with an acid, separating the fine particles from a solvent (dispersion medium), and performing concentration, desolvation, and desalting (deoxidation). By making the system acidic, the electrostatic repulsion force by the acidic hydrophilic portion is reduced, and the water-insoluble colorant fine particles are aggregated. In general, even when the pigment dispersion is agglomerated with an acid and then subjected to an alkali treatment, pigment fine particles are hardly redispersed and an increase in the primary particle size may be observed. On the other hand, according to the dispersion of the present invention, when an aqueous dispersion of fine particles of a water-insoluble colorant such as a pigment is prepared, and this is aggregated with an acid and the fine particles are redispersed, the primary particle size is increased. It can be greatly reduced.

In the present invention, the obtained water-insoluble colorant dispersion can be subjected to a heat treatment. Thereby, the crystallinity of the water-insoluble colorant is improved, and the weather resistance of the image using the ink obtained from the dispersion may be improved. In addition, filterability may be greatly improved by heat treatment, which can be said to be a useful process. The temperature of the heat treatment is preferably 40 to 100 ° C, more preferably 40 to 80 ° C, and most preferably 50 to 80 ° C. The heating time is preferably 10 minutes to 3 days, preferably 1 hour to 1 day, and more preferably 2 to 12 hours.

  As an acid used for agglomeration of fine particles of a water-insoluble colorant, pigment-containing particles in an aqueous dispersion that are difficult to precipitate are agglomerated to form a slurry, paste, powder, granule, cake (lumb), sheet It is preferable that it is made into a state that can be efficiently separated from the solvent by a normal separation method in the form of a shape, a short fiber shape, or a flake shape. More preferably, in order to separate the alkali used in the step of dissolving the water-insoluble colorant at the same time as the solvent, it is preferable to use an acid that forms a water-soluble salt with the alkali such as the phase transfer base used. Also preferred are those having high solubility in water. In order to efficiently perform desalting, the amount of acid to be added is preferably as small as possible within the range in which the fine particles aggregate. Specific examples include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid, trifluoroacetic acid, dichloroacetic acid, methanesulfonic acid and the like, with hydrochloric acid, acetic acid and sulfuric acid being particularly preferred. The aqueous dispersion of water-insoluble colorant fine particles that can be easily separated by an acid can be easily separated by a centrifugal separator, a filtration device, a slurry solid-liquid separation device, or the like. At this time, the degree of desalting and solvent removal can be adjusted by adding dilution water or increasing the number of decantations and washings.

  Furthermore, in the step of obtaining the water-insoluble colorant aggregate, the filterability can be improved by adding an organic solvent, which is a useful process. As the preferred solvent, any kind of aprotic organic solvent and protic organic solvent can be used, and specifically, polar solvents such as ethyl acetate, ethyl lactate, acetone, methyl ethyl ketone, acetonitrile, methanol ethanol, isopropanol are preferred. . Although the amount is not particularly limited, it is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass with respect to 100 parts by mass of the water-insoluble colorant dispersion.

  The agglomerates thus obtained can be used as a paste or slurry with a high water content, but as necessary, such as spray drying, centrifugal drying, filtration drying or freeze drying. It can also be used as a fine powder by a drying method.

  In the dispersion of the present invention, as a preferred embodiment, an aggregate is prepared from a primary dispersion (aqueous dispersion, reprecipitation liquid) obtained by mixing a water-insoluble colorant solution and an aqueous medium. It is preferable to add an aqueous medium to the aggregate and redisperse the fine particles to obtain a secondary dispersion (redispersion liquid). More preferably, an alkali treatment is performed at the time of this redispersion. That is, in this step including the alkali treatment, the acid groups coexisting by treating the fine particles of the water-insoluble colorant aggregated with, for example, an acid in the step of obtaining the aggregate with an alkali and adsorbing the fine particles, for example. It is possible to neutralize the high molecular compound having a function as a dispersant and effectively redisperse the water-insoluble colorant in the aqueous medium.

In the preferred embodiment of the present invention, since the desalting and the solvent removal have already been carried out in the aggregate formation step, a concentrated base of an aqueous dispersion of fine particles of water-insoluble colorant such as a pigment with few impurities is obtained. be able to. As the alkali used in the redispersion step, any alkali can be used as long as it acts as a neutralizing agent for the dispersant having an acidic hydrophilic portion and the solubility in water is enhanced. Here, “alkali” has the same meaning as the “base” described above. As alkali, specifically, hydroxide of alkali metal such as sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, aminomethylpropanol, dimethylaminopropanol, dimethylethanolamine, diethyltriamine, monoethanolamine, Examples include various organic amines such as diethanolamine, triethanolamine, butyldiethanolamine, and morpholine, and the above phase transfer bases. More specifically, ammonium compounds represented by the general formula (II) or (III) can be mentioned, and choline hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like are more preferable. Moreover, these 1 type (s) or 2 or more types can be used in combination.
The amount of the alkali used is not particularly limited as long as the aggregated particles can be stably redispersed in water. However, when used for applications such as printing ink and ink for inkjet printers, the corrosion of various members. Since it may become a cause, it is preferable to set it as the quantity which becomes pH 6-12, and it is more preferable to set it as the quantity used as the range of 7-11.

  In the above step of redispersing the aggregated water-insoluble colorant particles in an aqueous medium, a stirring, mixing, and dispersing device can be used as necessary. In particular, when using a paste or slurry of a water-insoluble colorant having a high water content, it is not necessary to add water. Furthermore, heating, cooling, distillation or the like can be performed for the purpose of increasing the efficiency of redispersion and for removing unnecessary water-soluble organic solvent or excess alkali.

  The recording liquid of the present invention can be prepared by using the above-described dispersion of the present invention and mixing, for example, predetermined components such as a polymer compound, a surfactant, and an aqueous solvent, and uniformly dissolving or dispersing them. The recording liquid of the present invention preferably contains 0.1 to 15% by mass of the water-insoluble colorant. In addition, when the prepared ink contains an excessive amount of a polymer compound or additive, the ink composition can be re-prepared by removing them appropriately by a method such as centrifugation or dialysis. The recording liquid of the present invention may be used alone, but may be combined with another ink to form the ink set of the present invention.

  The recording liquid of the present invention can be used in various image forming methods and apparatuses such as various printing methods, ink jet methods, and electrophotographic methods, and can be drawn by an image forming method using this device. Moreover, a fine pattern can be formed by this ink jet method, or a drug can be administered.

  The recording liquid of the present invention is preferably an inkjet recording liquid, and an ink set using the same is preferable. The recording liquid or ink set of the present invention is preferably used as a printed matter in which an image is recorded by means for applying the recording liquid to the medium, and the means adjusts the application amount or concentration of the recording liquid. It is preferable that the printed matter has a density adjusted by the means. Further, the recording liquid or ink set is preferably used in an image forming method having a step of recording an image by applying the recording liquid to a medium. Furthermore, in this invention, it can be set as the image forming apparatus which has a means for recording an image by providing a recording liquid to a medium using the said recording liquid or ink set.

  The dispersion of the present invention having the above-described excellent characteristics has a high density that is comparable to the current offset printing or letterpress printing that expresses the color tone by area ratio (area gradation) when ink is used.・ High-definition image recording can be realized.

  In the water-insoluble colorant dispersion of the present invention, the average particle diameter of the fine particles of the water-insoluble colorant is preferably 5 to 50 nm, more preferably 10 to 45 nm, and particularly preferably 15 to 40 nm. preferable. Thus, it is particularly preferable that the water-insoluble colorant is made into nanometer-sized fine particles from the viewpoint of coexistence of transparency of the dispersion, dispersion stability in the dispersion, and light resistance. If the average particle size is too small, it may be difficult to maintain a stable dispersion state in the dispersion for a long time, and good light resistance may not be obtained. On the other hand, if it is too large, the transparency of the dispersion may not be obtained. In the present invention, the water-insoluble colorant particles may contain two or more kinds of pigments, or may be composed of only pigments or may contain compounds other than pigments. At this time, it is preferable that the solid solution of 2 or more types of pigment comprises the particle | grains. However, a portion having a crystal structure and a portion not having a crystal structure may be mixed in the particles. In addition, pigments and / or other compounds may form particles by adsorbing so that the core of the particles is coated with the dispersant (polymer compound, surfactant, etc.).

  In the dispersion of the present invention, the water-insoluble colorant fine particles may be coated with a resin or an inorganic material. At this time, in order not to impair the color of the water-insoluble colorant, the resin and the inorganic material are preferably non-colored components. The average particle size of the fine particles coated with the resin or the inorganic material is preferably 6 to 200 nm, and when used as an inkjet recording liquid, it is further preferably 6 to 150 nm from the viewpoint of obtaining good ejection stability. The thickness is preferably 6 to 100 nm.

In the present invention, the particle size of the water-insoluble colorant dispersed in the dispersion is preferably monodispersed. By being monodispersed, the influence of light scattering and the like of particles having a large particle diameter can be reduced. For example, when forming aggregates by printing, recording, etc. using the dispersion, control of the filling form of the aggregates to be formed Etc. are advantageous. As an index for evaluating the dispersibility of the dispersion, for example, in the arithmetic average particle size obtained by the dynamic light scattering method, the particle size distribution function of the particles is dG = f (D) × dD (G is the number of particles, D is the primary particle size) (Represents particle size)
The difference between the particle size (D90) occupying 90% by number of the total number of particles and the particle size (D10) occupying 10% by number can be used. In the present invention, the difference between D90 and D10 is preferably 45 nm or less, more preferably 1 to 30 nm, and particularly preferably 1 to 20 nm. This method can also be applied to a particle size distribution curve produced using the particle size observed with the transmission electron microscope described above.

  Further, as another example of an index indicating dispersibility, a ratio (Mv / Mn) of volume average particle diameter (Mv) and number average particle diameter (Mn) obtained by a dynamic scattering method can be used. In the dispersion of the present invention, the Mv / Mn value is preferably 1.5 or less, more preferably 1.4 or less, and further preferably 1.3 or less.

  In the present invention, the average particle size of the dispersion by dynamic light scattering is diluted with ion-exchanged water so that the water-insoluble colorant concentration is 0.1% by mass, and then LB-500 (trade name) manufactured by HORIBA, Ltd. is used. This is the value measured using an optical light scattering meter. At this time, the number average particle diameter Mn can be measured in addition to the volume average particle diameter Mv of each dispersion. Evaluation of average particle diameter by observation with a transmission electron microscope (TEM) is performed by dropping a diluted dispersion on Cu200 mesh with a carbon film attached and then drying, and 100,000 times with TEM (1200EX (trade name) manufactured by JEOL). Is a value obtained by measuring the major axis of 300 independent particles not overlapping from each other and calculating the average value as the average particle size. Hereinafter, the average particle diameter measured by a dynamic light scattering measuring instrument is referred to as “dynamic light scattering average particle diameter”, and the average particle diameter calculated by TEM observation is sometimes referred to as “TEM average particle diameter”.

The present invention will be described below in more detail based on examples, but the present invention is not limited to these examples. In the text, “parts” and “%” are based on mass unless otherwise specified.
(Example 1 and Comparative Example 1)
(Example 1-1)
C. I. Pigment Red 122 13.2 parts by mass, the exemplified polymer compound (D-1) (acid value 200 mg KOH / g, Mw = 18000) 6.6 parts by mass, dimethyl sulfoxide 160 parts by mass, tetramethylammonium hydroxide (Alfa Aesar) Co., Ltd. 25% methanol solution) [co-dissolving base] 39 parts by mass was mixed, heated to 60 ° C., and stirred for 2 hours to co-dissolve the pigment and polymer compound (D-1). A deep blue-violet pigment solution was obtained.

  After ultrasonically treating this pigment solution, it is rapidly injected into 2000 parts by mass of ion-exchanged water (water temperature of 12 ° C. by an ice bath) stirred with a stirrer using a liquid feed pump at 100 ml / min. As a result, a reddish pigment dispersion (reprecipitation liquid) was obtained. The volume average particle size of the pigment dispersion obtained by the dynamic light scattering method is 37.4 nm (TEM average particle size: 25.3 nm), and the dispersion containing fine pigment fine particles is suppressed while suppressing the progress of the aggregation state. It was possible to get There was no change in the particle size after storage for 2 weeks, and no sediment was observed. Furthermore, this was a kinetically formed loose aggregation state, and could be refined to a volume average particle size of 31.2 nm with an ultrasonic homogenizer or with a time of one month.

    Next, this pigment dispersion was put into a 3 L flask, heated to 50 ° C. and stirred for 3 hours. Next, after cooling to room temperature, 11 ml of hydrochloric acid was added dropwise to adjust the pH to about 3, and the pigment particles were aggregated from the pigment dispersion. Thereafter, 200 ml of ethyl acetate was further added and stirred for 2 hours, followed by filtration under reduced pressure using a membrane filter having an average pore size of 0.2 μm, washing with ion exchange water twice, and vacuum drying (45 ° C.) for one day. Then, a desalted and desolvated PR-122 (quinacridone organic pigment) / polymer compound (D-1) aggregated powder was obtained.

  Next, 0.5 parts by mass of tetramethylammonium hydroxide (15% by weight aqueous solution) [base for redispersion] is added to this part by weight of ion powder, and ion-exchanged water [aqueous medium for redispersion] is added to a pigment content of 10%. Then, redispersion treatment by ultrasonic treatment was performed to obtain a pigment dispersion (redispersion). The number average particle diameter of this pigment dispersion by dynamic light scattering method is 27.6 nm (TEM average particle diameter: 25.4 nm), and a high-concentration dispersion containing pigment fine particles having very high monodispersibility is obtained. It was. There was no change in the particle size after storage for 2 weeks, and no sediment was observed.

(Example 1-2)
In Example 1-1, the pigment was changed to C.I. I. Instead of pigment red 254, the used mass part of the pigment was C.I. I. A primary pigment dispersion (reprecipitation liquid) and a secondary pigment dispersion (redispersion liquid) having a pigment content of 10% were obtained in the same manner except that the amount was the same as that of Pigment Red 122. This pigment dispersion (redispersion) has a number average particle size of 36.6 nm (TEM average particle size: 29.2 nm) by dynamic light scattering, and suppresses the progress of the aggregation state and contains fine pigment particles. It was possible to obtain a high concentration dispersion. There was no change in the particle size after storage for 2 weeks, and no sediment was observed.

(Example 1-3)
In Example 1-1, the pigment was changed to C.I. I. Instead of pigment yellow 74, the used mass part of the pigment was C.I. I. A primary pigment dispersion (reprecipitation liquid) and a secondary pigment dispersion (redispersion liquid) having a pigment content of 10% were obtained in the same manner except that the amount was the same as that of Pigment Red 122. This pigment dispersion (redispersion) has a number average particle diameter of 38.5 nm (TEM average particle diameter: 24.5 nm) by dynamic light scattering, and no change is observed in the particle diameter after storage for 2 weeks. In addition, no sediment was observed.

(Comparative Example 1-1)
C. I. Pigment Red 122 13.2 parts by mass, polyvinylpyrrolidone (hereinafter PVP), manufactured by Wako, Mw = 25000) 6.6 parts by mass, dimethyl sulfoxide 160 parts by mass, tetramethylammonium hydroxide (Alfa Aesar, 25% methanol solution) ) [Base for co-dissolution] 39 parts by mass were mixed, heated to 60 ° C., and stirred for 2 hours to co-dissolve the pigment and the styrene / methacrylic acid copolymer to dissolve the deep blue-violet pigment. A liquid was obtained.
After ultrasonically treating this pigment solution, it is rapidly injected into 2000 parts by mass of ion-exchanged water (water temperature of 12 ° C. by an ice bath) stirred with a stirrer using a liquid feed pump at 100 ml / min. As a result, a reddish pigment dispersion (reprecipitation liquid) was obtained. The volume average particle diameter of the pigment dispersion obtained by the dynamic light scattering method is 189.4 nm (TEM average particle diameter: 29.5 nm), and the primary particles are fine, but the secondary particles are formed. Was a large and agglomerated dispersion. Aggregation progressed with time, and a large amount of sediment was observed after 3 days.

    Next, this pigment dispersion was put into a 3 L flask, heated to 50 ° C. and stirred for 3 hours. Next, after cooling to room temperature, 11 ml of hydrochloric acid was added dropwise to adjust the pH to about 3, and the pigment particles were aggregated from the pigment dispersion. Thereafter, 200 ml of acetone was further added and stirred for 2 hours, followed by filtration under reduced pressure using a membrane filter having an average pore size of 0.2 μm, washing twice with ion-exchanged water, and vacuum drying (45 ° C.) for one day. A desalted and solvent-removed PR-122 (quinacridone organic pigment) / PVP aggregated powder was obtained.

  Next, 0.5 part by mass of sodium oleate [re-dispersing surfactant] is added to 1 part by mass of this powder, and ion-exchanged water [re-dispersing aqueous medium] is added so that the pigment content becomes 10%. Then, redispersion treatment by ultrasonic treatment was performed to obtain a pigment dispersion (redispersion). The number average particle diameter of this pigment dispersion by dynamic light scattering was 56.6 nm (TEM average particle diameter: 29.4 nm), and a dispersion liquid with a slightly advanced aggregation state was obtained. Moreover, the particle size after storage for 2 weeks greatly increased and aggregation proceeded to 108.2 nm.

(Comparative Example 1-2)
C. I. Pigment Red 122 13.2 parts by mass, styrene / methacrylic acid copolymer (dispersant A) (acid value 180 mgKOH / g, Mw = 18000) 6.6 parts by mass, dimethyl sulfoxide 160 parts by mass, tetramethylammonium hydroxide ( Alfa Aesar 25% methanol solution) [Co-dissolving base] 39 parts by mass were mixed, heated to 60 ° C., and stirred for 2 hours to co-dissolve the pigment and styrene / methacrylic acid copolymer. Thus, a deep blue-violet pigment solution was obtained.
After ultrasonically treating this pigment solution, it is rapidly injected into 2000 parts by mass of ion-exchanged water (water temperature of 12 ° C. by an ice bath) stirred with a stirrer using a liquid feed pump at 100 ml / min. As a result, a reddish pigment dispersion (reprecipitation liquid) was obtained. The volume average particle size of the pigment dispersion obtained by the dynamic light scattering method is 145.4 nm (TEM average particle size: 28.5 nm), and the primary particles are fine, but the secondary particles are formed. Was a large and agglomerated dispersion.

  Next, this pigment dispersion was put into a 3 L flask, heated to 50 ° C. and stirred for 3 hours. Next, after cooling to room temperature, 11 ml of hydrochloric acid was added dropwise to adjust the pH to about 3, and the pigment particles were aggregated from the pigment dispersion. Thereafter, 200 ml of ethyl acetate was further added and stirred for 2 hours, followed by filtration under reduced pressure using a membrane filter having an average pore size of 0.2 μm, washing with ion exchange water twice, and vacuum drying (45 ° C.) for one day. Then, a desalted and desolvated PR-122 (quinacridone organic pigment) & styrene / methacrylic acid copolymer aggregated powder was obtained.

  Next, 0.5 parts by mass of tetramethylammonium hydroxide (15% by weight aqueous solution) [base for redispersion] is added to 1 part by weight of this powder body, and ion-exchanged water [water for redispersion] is added to a pigment content of 10%. After adding the medium], redispersion treatment by ultrasonic treatment was performed to obtain a pigment dispersion (redispersion). The number average particle diameter of this pigment dispersion by the dynamic light scattering method was 47.6 nm (TEM average particle diameter: 27.1 nm), and a dispersion liquid with a slightly advanced aggregation state was obtained. In addition, the particle size after storage for 2 weeks greatly increased, and aggregation proceeded to 79.1 nm.

(Examples 1-4 to 1-10, Comparative Examples 1-3 and 1-4)
In the same manner as in Examples 1-1 to 1-3 and Comparative Examples 1-1 and 1-2, except that the pigment to be used and / or the agent to be added were changed as shown in Table 1, pigment dispersion (reprecipitation) Liquid, redispersion liquid). The results of measuring the average particle size of the pigment fine particles in each dispersion are shown in Table 1.

(Example 2 and Comparative Example 2)
(Adjustment of ink composition)
Next, 50 parts by mass of the pigment dispersion (redispersion liquid) obtained in Example 1 and Comparative Example 1 was used, respectively, 7.5 parts by mass of diethylene glycol, 5 parts by mass of triethylene glycol monobutyl ether, and 5 parts by mass of trimethylolpropane. After mixing with 0.2 parts by mass of acetylenol EH (trade name, manufactured by Kawaken Fine Chemical Co., Ltd.) and 32.3 parts by mass of ion-exchanged water, the mixture was sonicated to obtain ink compositions.

[Evaluation of storage stability]
With respect to the obtained ink composition, first, the dynamic light scattering average particle size on the day of preparation was measured. Next, the ink composition was subjected to forced aging for one week under heating at 60 ° C., and then the average particle size by dynamic light scattering was measured again. The particle diameter variation rate at this time is shown in the table. If this particle diameter variation rate is low, it can be said that the ink composition has high storage stability.

Abbreviations in the table mean the following.
TMAH: Tetramethylammonium hydroxide (clogP: -4.586)
Dispersant A: Styrene / methacrylic acid copolymer * Acid value 180 mgKOH / g, Mw = 18000
Sodium oleate

As shown in the results of Table 1, in the dispersion of the comparative example, the pigment fine particles contained therein were easy to aggregate and the storage stability was extremely low. Thus, it can be seen that the dispersion of the comparative example cannot satisfy the practically required level when it is used as an ink.
On the other hand, the dispersion of the present invention (Example) gives a dispersion containing fine pigment fine particles in both the reprecipitation liquid and the redispersion liquid, and also has storage stability after being made into an ink with a hydrophobic solvent. It was extremely high and was found to have a remarkable effect in suppressing secondary aggregation.

(Evaluation of ejection properties)
The prepared ink composition is packed in a cartridge of an ink jet printer (PX-G930 (trade name), manufactured by Epson Corporation), and is placed on an ink jet paper (photo paper <gloss> (trade name) manufactured by Epson Corporation). A solid image (reflection density is 1.0) was printed on the entire surface, the number of white streaks was measured, and the ejection property was evaluated according to the following criteria.

3: No white streak, which is an unprinted part, is generated on the entire printing surface. 2: Slight white streaking is observed, but is practically acceptable. 1: Many white streaks occur on the entire printing surface. Table 2 shows the evaluation results, which are unacceptable quality for practical use.

[Table 2]
-----------------
Ink composition ^* Dischargeability -----------------
Example 1-1 3
Example 1-2 3
Example 1-5 3
Example 1-10 3
Example 1-11 3
Comparative Example 1-1 1
Comparative Example 1-2 2
Comparative Example 1-4 1
----------------
* Indicated by the numbers of the examples and comparative examples in which the pigment dispersions used for the preparation of the ink composition were prepared.

  As can be seen from Table 2 above, it can be seen that the ink compositions prepared using the pigment dispersions of the examples are excellent in ejection properties.

[Evaluation of transparency]
Each of the above ink compositions was coated on a polyethylene terephthalate (PET) sheet having a thickness of 60 μm with a bar coater and dried, and then the transparency was visually evaluated.
2: Good 1: Bad [Evaluation of pigment particle diameter]
The TEM average particle diameter of the pigment fine particles in the ink composition was measured and calculated according to the method described above.
Each evaluation result is shown in Table 3.

[Table 3]
-----------------------------------
Sample ^* TEM average particle size [nm] Transparency ----------------------------------
Example 1-1 25.3 2
Example 1-2 29.2 2
Example 1-5 29.6 2
Example 1-10 25.3 2
Example 1-11 39.7 2
Comparative Example 1-1 29.5 1
Comparative Example 1-2 28.5 1
Comparative Example 1-4 26.9 1
----------------------------------
* Indicated by the numbers of the examples and comparative examples in which the pigment dispersions used in the preparation of the ink composition were prepared.

  As can be seen from Table 3, the printed matter using the ink composition of the present invention is excellent in transparency even at a high concentration, and is useful as an ink composition.

  From the above results, in the dispersion using the acid group-containing polymer compound having a heterocycle of the present invention, the fine pigment particles contained therein can be kept fine for a long period without secondary aggregation. I understand that I can do it. For this reason, it is possible to obtain an ink composition that has high ejection stability when converted into ink, high transparency even in a high concentration region, and high color reproducibility.

Claims (14)

A water-insoluble colorant dispersion containing fine particles of a water-insoluble colorant, an aqueous medium, and a polymer compound, wherein the polymer compound comprises a carboxylic acid group, a sulfonic acid group, a phosphate group, and a hydroxyl group A polymerizable compound that forms a hydrophilic site when polymerized with at least one acid group selected from the above, a styrene polymerizable compound that forms a hydrophobic site when polymerized, which may have a substituent, and the following: A water-insoluble colorant dispersion obtained by polymerizing a styrene polymerizable compound represented by the general formula (I).

[In Formula (I), Ring A is a heterocyclic group containing a nitrogen atom. The heterocyclic group A may further have a ring substituent, or may be condensed with another ring. ]   The water-insoluble colorant dispersion according to claim 1, further comprising an inorganic or organic base. The water-insoluble colorant dispersion according to claim 2, wherein the organic base is a phase transfer base represented by the following general formula (II) or (III).

[In formulas (II) and (III), R _{1 to} R ₅ are each independently an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an aryl group, or an alkylaryl group. n is an integer of 1-4. ]   The water-insoluble colorant dispersion according to any one of claims 1 to 3, wherein the acid group is a carboxylic acid group.   The water-insoluble colorant is an organic pigment selected from the group consisting of a quinacridone organic pigment, a diketopyrrolopyrrole organic pigment, and a monoazo yellow organic pigment. A water-insoluble colorant dispersion. A water-insoluble colorant dispersion in which a polymer compound and a water-insoluble colorant are co-dissolved in an organic solvent in the presence of an inorganic or organic base, and the solution is mixed with an aqueous medium to form fine particles of the water-insoluble colorant. A hydrophilic site when the polymer compound is polymerized with one or more acid groups selected from the group consisting of carboxylic acid groups, sulfonic acid groups, phosphoric acid groups, and hydroxyl groups. Polymerizing a polymerizable compound formed, a styrene polymerizable compound that forms a hydrophobic site when polymerized, which may have a substituent, and a styrene polymerizable compound represented by the following general formula (I) A method for producing a water-insoluble colorant dispersion characterized by the above.

[In Formula (I), Ring A is a heterocyclic group containing a nitrogen atom. The heterocyclic group A may further have a ring substituent, or may be condensed with another ring. ]   The water-insoluble colorant dispersion according to claim 6, wherein the water-insoluble colorant is an organic pigment selected from the group consisting of a quinacridone organic pigment, a diketopyrrolopyrrole organic pigment, and a monoazo yellow organic pigment. Manufacturing method.   A water-insoluble colorant dispersion containing the fine particles of the water-insoluble colorant, the aqueous medium, and the polymer compound obtained by the production method according to claim 6 or 7.   A recording comprising 0.1 to 15% by mass of the water-insoluble colorant fine particles in the water-insoluble colorant dispersion according to any one of claims 1 to 5 and 8, based on the total mass of the recording liquid. liquid.   The recording liquid according to claim 9, wherein the recording liquid is an inkjet recording liquid.   An ink set using the inkjet recording liquid according to claim 10.   A printed matter in which an image is recorded by means for applying a recording liquid to a medium using the recording liquid according to claim 9 or 10 or the ink set according to claim 11, wherein the means applies the recording liquid. A print having a function of adjusting the amount or density, and the density of the print being adjusted by the means.   An image forming method comprising a step of recording an image by applying a recording liquid to a medium using the recording liquid according to claim 9 or 10 or the ink set according to claim 11.   An image forming apparatus comprising means for recording an image by applying a recording liquid to the medium using the recording liquid according to claim 9 or 10 or the ink set according to claim 11. .