JP5488900B2 - Pigment dispersion composition and inkjet ink composition - Google Patents

Description

  The present invention relates to a pigment dispersion composition and an inkjet ink composition.

In recent years, water-based inks have been widely used to replace organic solvent-based inks in a wide range of fields because of their safety and low environmental impact. Especially for business applications, water-free color materials that are odorless are essential as inks used for various printing in offices. For industrial applications, organic solvents can be used due to problems in the working environment, safety of ink and paint handling, and waste liquid treatment. There is an increasing tendency to use as little as possible. In addition, water-based colorants are also more popular than organic solvent-type colorants because they do not require special equipment such as explosion-proof equipment, exhaust equipment, and organic solvent recovery equipment during production. .

  As water-based colorants, two types of dyes and pigments are used depending on the application. Dyes are excellent in gradation and easy to form high-resolution images, but they have poor light resistance compared to pigments and have practical problems. There is. In contrast, pigments are inferior in dispersibility to dyes, but are extremely excellent in water resistance and light resistance, and many pigment inks have been provided by the advancement of dispersion technology.

  Gravure inks that are printed via printing plate making and water-based liquid inks for offset printing have been developed, but the most popular recording method for offices that uses water-based inks is the ink jet recording method.

  The ink jet recording method is a method in which ink droplets are ejected from a fine nozzle head and characters and images are recorded on the surface of a recording medium such as paper. Since it can be easily printed on demand without making a full color printing plate on a simple recording medium, it has begun to spread widely.

  An ink jet printer that employs an ink jet recording method is a method in which ink droplets are ejected from a fine nozzle head and characters and images are recorded on the surface of a recording medium such as paper. (Registered trademark) method and piezo method. The former is a recording method that instantaneously heats the ink guided to the nozzle head with a heater to generate bubbles, and the ink expansion is intermittently ejected by volume expansion due to the bubbles, the latter is an electrostrictive element (piezoelectric element) Is a recording method in which an electrical signal is converted into a mechanical signal using ink and ink droplets stored in a nozzle head portion are ejected intermittently.

  Among ink compositions for inkjet printers (inkjet ink compositions), black ink compositions are widely used in offices and the like mainly for the purpose of document printing, and are water-based optimized for the recording method and recording speed of each printer. Many black pigment ink compositions are provided.

  For example, an aqueous black pigment ink composition in which the surface of a black pigment is hydrophilized to improve dispersibility in an aqueous medium has been proposed (see, for example, Patent Document 1). When the ink is printed on the paper, the ink composition penetrates into the paper, which causes problems such as a decrease in image density, an offset, and curling of the recording paper. In particular, with the recent increase in printing speed of ink jet printers, the amount of ink discharged per unit time tends to increase, so that conventional aqueous black pigments may not provide sufficient image density.

  In addition, since pigments have a weak affinity with other substances such as organic polymers, water, and organic solvents compared to the cohesion between particles, they are uniformly mixed or dispersed under normal mixing or dispersion conditions. It is extremely difficult to adsorb a dispersant made of various surfactants, resins, etc. on the pigment surface, and the entire pigment surface is coated with the dispersant, so that it can be mixed with other solid or liquid components. Many studies have been made to improve the dispersibility of the pigment by increasing the affinity (for example, see Patent Document 2).

  In addition, in industrial applications, the printing speed of the printer is fast, and unlike in personal applications, head cleaning cannot be performed frequently. As an ink-jet ink composition, the head becomes soiled or clogged even after repeated continuous and intermittent ejection. Re-dissolvability (characteristic that the ink composition after drying is re-dissolved in the undried ink composition and does not cause dirt or clogging in the nozzle head even if continuous discharge and intermittent discharge are repeated) is required. It has become.

Japanese Patent Laid-Open No. 08-003498 Japanese Patent Application Laid-Open No. 08-2158015

  However, as a result of diligent investigations by the present inventors, in a conventional aqueous pigment ink composition in which a dispersant is adsorbed on the pigment surface, the ink composition is ejected from a thin nozzle provided in the nozzle head. It has been found that the dispersion state of the pigment becomes unstable due to the release of the dispersant due to the application of a strong shearing force or the release of the dispersant during long-term storage, leading to deterioration in storage stability. When an aqueous dispersion resin such as an acrylic emulsion is added to improve the scratch resistance and marker resistance of the ink coating film, storage stability and ejection stability are lowered. In addition, when the entire pigment is coated with a dispersant and microencapsulated, the storage stability is excellent, but the image density is greatly reduced.

  In addition, it is known that a colorant that lowers the functional group concentration on the pigment surface and does not penetrate into the printed material such as paper and remains on the surface has a higher image density. It will reduce the solubility and scratch resistance.

  Therefore, the present invention provides a pigment dispersion composition and an inkjet ink composition that exhibit excellent image density, dispersibility, and storage stability, have high re-dissolvability, and are excellent in marker resistance and scratch resistance of an ink coating film. Is intended to provide.

  In order to solve the above technical problem, the present inventors diligently studied, and as a result, the pigment (I) having an acidic group on the surface and two or more amino groups selected from primary amino groups and secondary amino groups in the molecule. A basic compound (II) is contacted in an aqueous medium to prepare a pigment having an unreacted amino group on the surface, and is further contacted with a polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups. The above technical problem is solved by a pigment dispersion composition or inkjet ink composition comprising a polymer-added pigment aqueous dispersion (A) that is bonded and an aqueous dispersion resin (B) having an average particle diameter of 10 to 300 nm. Based on this finding, the present invention has been completed.

That is, the present invention
(1) A pigment (I) having an acidic group on the surface thereof and a basic compound (II) having two or more amino groups selected from primary amino groups and secondary amino groups in the molecule are contacted in an aqueous medium. An aqueous dispersion of a polyurethane resin-added pigment (A) obtained by preparing a pigment having an unreacted amino group on the surface and then bringing it into contact with a polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups to form a urea bond When,
A pigment dispersion composition comprising an aqueous dispersion resin (B) having an average particle diameter of 10 to 300 nm,
(2) The pigment dispersion composition according to (1), wherein the polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups has a solid content acid value of 20 to 200 mgKOH / g,
(3) An emulsifier-dispersed aqueous solution in which the aqueous dispersion resin (B) is a self-dispersing aqueous dispersion resin having an anionic group or a nonionic group in the molecule, or is dispersed by an anionic emulsifier and / or a nonionic emulsifier. The pigment dispersion composition according to (1) or (2), which is a dispersion resin,
(4) The pigment dispersion composition according to any one of the above (1) to (3), wherein the pigment (I) having an acidic group on the surface is self-dispersing carbon black having an acidic group on the surface,
(5) An inkjet ink composition comprising the pigment dispersion composition according to any one of (1) to (4) above,
(Hereinafter, the pigment (I) having an acidic group on the surface is appropriately referred to as “Pigment (I)”, and two or more amino groups selected from primary amino groups and secondary amino groups are included in the molecule. The basic compound (II) having a basic isocyanate (II) and the polyisocyanate polyurethane resin (III) having a terminal isocyanate group are referred to as a “polyisocyanate polyurethane resin (III)”, respectively.

  According to the present invention, a pigment (I) having an acidic group on its surface and a basic compound (II) having two or more amino groups selected from primary amino groups and secondary amino groups in the molecule are present in an aqueous medium. By bringing them into contact with each other in advance, the polyisocyanate polyurethane resin (III) having a terminal isocyanate group is brought into close proximity by an ionic acting force, whereby an unreacted amino group on the pigment surface and the polyisocyanate polyurethane resin (III ) And a polyurethane resin-added pigment (A) formed by urea bonding, together with an aqueous dispersion resin (B) having an average particle size of 10 to 300 nm, exhibits excellent image density, dispersibility and storage stability. In addition, the pigment dispersion composition and the ink jet are highly re-dissolvable and have excellent marker resistance and scratch resistance of the ink coating film. It is possible to provide an ink composition.

First, the pigment dispersion composition of the present invention will be described.
The pigment dispersion composition of the present invention comprises a pigment (I) having an acidic group on the surface and a basic compound (II) having two or more amino groups selected from primary amino groups and secondary amino groups in the molecule. After making a pigment having an unreacted amino group on the surface by contacting in a medium, it is further contacted with a polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups to make a urea resin-bonded pigment ( The aqueous dispersion of A) and an aqueous dispersion resin (B) having an average particle diameter of 10 to 300 nm are included.

  In the pigment dispersion composition of the present invention, the pigment (I) having an acidic group on the surface is preferably a pigment having an acidic surface. Various pigments that have been surface-treated with synergists, and pigments that have been acidified by surface treatment are further treated. Mention may be made of pigments neutralized with ions.

  In the pigment dispersion composition of the present invention, the pigment (I) having an acidic group on the surface is preferably a black pigment, and specifically, ivory black, peach black, lamp black, mars black, bitumen, titanium black, carbon Black etc. can be mentioned. Among these, carbon black, as a black pigment for inkjet recording, is excellent in jetness and coloring power, and therefore can be suitably used, and considering the dispersibility and ejection stability of the ink composition, In particular, self-dispersing carbon black having an acidic group on the surface is suitable.

  The self-dispersing carbon black pigment having an acidic group on the surface is obtained by bonding at least one hydrophilic group containing an acidic group to the surface of the carbon black pigment directly or through another atomic group, When a suspension is made into a dispersion, a stable dispersion state can be maintained without adding a surfactant or a polymer compound, and the surface tension of the dispersion shows almost the same value as water. In the present application document, the self-dispersing carbon black pigment includes those obtained by neutralizing a hydrophilic group such as the acidic group with a counter ion.

  Examples of carbon black include furnace black, channel black, acetylene black, and thermal black. These carbon blacks have a high carbon content and high blackness derived from an amorphous structure. Compared to black and the like, the drying rate is high, the storage stability is high, and the cost is low.

  Among the above-mentioned carbon blacks, when ultrafine carbon black such as furnace black or channel black is used, when the obtained aqueous pigment dispersion is used in an ink composition for an ink jet printer, a high resolution and excellent print quality is obtained. be able to.

The carbon black is preferably one nitrogen adsorption specific surface area _(N 2 SA) is ^{50 m} 2 / g or more, more preferably those wherein 50 to 300 m ² / g, still those that are 80~250m ² / g preferable. As the carbon black is preferably one DBP absorption is 50 cm ^3/100 g or more, more preferably those which are 50 to 200 cm ^3/100 g, more preferably those which are 80~180cm ³ / 100g.

Due to the N ₂ SA and DBP absorption amounts of carbon black being in the above range, when the obtained aqueous pigment dispersion is used in an inkjet ink composition, it has excellent dispersibility and ink performance with respect to an aqueous medium. It can be demonstrated.

Note that in the present application, N ₂ SA of carbon black is defined in JIS K6217-2 "Carbon black for rubber industry - basic characteristics - Part 2 Determination of specific surface area - nitrogen absorption method, a single-point method" The DBP absorption amount means a value measured according to “Carbon Black for Rubber—Basic Properties—Part 4, Determination of DBP Absorption” defined in JISK6217-4.

  The average particle size of the primary particles constituting the carbon black is preferably 10 to 300 nm, more preferably 15 to 270 nm, and further preferably 20 to 250 nm. In addition, in this application document, the average particle diameter of the primary particle which comprises carbon black means the arithmetic mean when the particle diameter of 2000-10000 primary particles is measured with the electron microscope with a resolution | decomposability of 15 or more.

  Specific examples of carbon black include Talker Black # 8500, Talker Black # 8500F, Talker Black # 7550SB, Talker Black # 7550F (manufactured by Tokai Carbon Co., Ltd.), # 650, # 750, MA600, # 44B, # 44. # 45B, MA7, MA11, # 47, # 45, # 33, # 45L, # 47, # 50, # 52, MA77, MA8 (manufactured by Mitsubishi Chemical Corporation), FW200, FW2V, FWI, FW18PS, NIpex180IQ, FW1, Special Black6, S160, S170 (above Degussa), Black Pearls 1000M, Black Pearls 800, Black Pearls 880, Monarch 1300, Monarch 700, Monarch 80 , CRX 1444, Regal 330R, Regal 660R, Regal 660, Regal 415R, Regal 415, Black Pearls 4630, Monarch 4630 (above made by Cabot), Raven 7000, Raven 3500, Raven 5250, Raven 5250, Raven 5250, Raven 5250, Raven 5250 Raven 1255, Raven 1250, Raven 1190, Raven 1000, Raven 1020, Raven 1035, Raven 1100ULTRA, Raven 1170, Raven 1200 (above made by Columbian), DB1305 (700 KOSU BL, 70 from SOS 7) , 725, 300, 30 320, 325, X25, X45 (above Asahi Carbon Co., Ltd.), N220, N110, N234, N121 (above Sid Richardson), Niteron # 300 (above Nisshin Carbon Co., Ltd.), Show Black N134, N110, N220, N234, N219 (manufactured by Showa Cabot) can be used.

  In the pigment dispersion composition of the present invention, the pigment (I) having an acidic group on the surface can be obtained by appropriately oxidizing each of the above pigments.

The oxidation treatment can be performed by a known method such as a liquid phase method or a gas phase method.
When oxidizing by the liquid phase method, various oxidizing agents such as hydrogen peroxide, nitric acid, sulfuric acid, chlorate, persulfate, percarbonate can be used as the oxidizing agent. A pigment having an acidic group on the surface can be obtained by adding a pigment such as carbon black into an aqueous solution containing a mixture and stirring, and by controlling the amount of oxidant added and the reaction temperature, carbon black can be obtained. Acidic groups can be uniformly introduced on the surface.

  Further, the oxidation treatment by the gas phase method can include a method by ozone oxidation or air oxidation. According to the gas phase method, the drying cost is not required and the operation is easier than the liquid phase method. There are advantages.

  The acidic group introduced into the pigment surface by the oxidation treatment is not particularly limited as long as it can form a salt by reacting with an amino group-containing basic compound with an acid / base, such as a carboxyl group or a sulfone group. Can be mentioned. The introduction amount of these acidic groups can be controlled by controlling gas phase oxidation conditions or liquid phase oxidation conditions.

  Hereinafter, as an example, a case where an oxidation-treated product of carbon black is produced by a liquid phase method as a black pigment having an acidic group on the surface will be described.

  Carbon black, an oxidizing agent and an aqueous medium (preferably deionized water) are mixed in an appropriate amount ratio in an agitation tank, and an appropriate temperature in the mixing agitation tank, for example, a temperature of room temperature to 90 ° C. is preferable. Is a surface in which carbon black is oxidized by sufficiently stirring and mixing at a temperature of 60 to 90 ° C., and a hydrophilic functional group such as a carboxyl group or a hydroxyl group is generated on the surface of the carbon black particle aggregate. An aqueous dispersion (slurry) of the pigment in which is oxidized can be obtained.

In this case, if the carbon black is previously wet or dry oxidized, the carbon black can be efficiently dispersed in the slurry, and acidic groups can be generated uniformly and effectively. When oxidizing by wet method, it is preferable to oxidize with ozone water, hydrogen peroxide solution, peroxodiacid or salts thereof, and when oxidizing by dry (gas phase) method, ozone, oxygen, NO _X , SO _X, etc. It is preferable to oxidize by exposing carbon black to a gas atmosphere.

  Further, it is also preferable to add a surfactant in order to uniformly disperse the pigment whose surface has been oxidized in the slurry, and any of anionic, nonionic, and cationic types can be used as the surfactant. For example, anionic surfactants include fatty acid salts, alkyl sulfate esters, alkylaryl sulfonates, and the like, and nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, and the like. Examples of the surfactant include alkylamine salts and quaternary ammonium salts.

  The thus obtained pigment slurry having the oxidized surface may be directly subjected to a reaction with a basic compound, or aggregates of the pigment having an oxidized surface may be generated or the viscosity may be increased. In order to suppress this, partial neutralization treatment (treatment for neutralizing a part of acidic groups that are surface functional groups) may be performed.

  When performing the partial neutralization treatment, it is preferable to remove in advance the reduction salt (reduced product of the oxidizing agent) generated by the oxidation treatment. By removing the reduction salt, the following neutralization reaction proceeds efficiently. Thus, water dispersibility is improved, and re-aggregation of the surface oxidized pigment can be suppressed. The reduction salt is preferably removed using a separation membrane such as an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), and an electrodialysis membrane.

  The partial neutralization treatment of the surface oxidized pigment is preferably performed while adding a neutralizing agent to the slurry and heating. Examples of the neutralizing agent include alkali salts such as potassium hydroxide and sodium hydroxide, and organic amines such as ammonia, ethanolamine, triethanolamine, dimethylaminoethanol and quaternary amine, but are not limited thereto. . The addition amount of the neutralizing agent varies depending on the pigment surface functional group amount, and thus cannot be generally determined, but it is preferably 50 to 100 mol% with respect to the surface acidic functional group. The neutralization reaction may be performed at room temperature, but it is preferable to add a neutralizing agent to the pigment slurry in the stirring tank and stir at 40 to 100 ° C. for 1 to 16 hours.

  In general, the self-dispersing pigment, that is, the pigment (I) having an acidic group on the surface, when neutralized by counter ions, the pigment particles are dispersed by repulsion of ions, and when the polymer is added to the surface, its storage stability However, when the concentration of acidic groups on the pigment surface is low, dispersion stability may be lacking. On the other hand, the polyurethane resin-added pigment (A) used in the present invention has a terminal isocyanate group on the surface described later with respect to the pigment (I) even when the acidic group concentration on the surface of the pigment (I) is low. When the polyisocyanate polyurethane resin (III) having 2 or more is added by a urea bond, excellent dispersibility and dispersion stability can be imparted.

When large undispersed lumps or coarse particles are present in the pigment slurry, it is preferably removed by a method such as centrifugation or filtration, and the aqueous pigment obtained by removing undispersed lumps or coarse particles The particle size distribution of the dispersion can be controlled, and the occurrence of nozzle clogging during printing can be suppressed when the aqueous pigment dispersion is used in an ink composition for an ink jet printer.
When neutralization of the slurry is performed, it is preferable to remove salts (oxide of neutralizing agent) generated by the neutralization treatment, and by removing the salts, the water dispersibility of the pigment is improved, It is possible to suppress the re-simulation of the surface oxidized pigment. The salt is preferably removed by a separation membrane such as an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), and an electrodialysis membrane.

  When the pigment (I) having an acidic group on the surface is carbon black having an acidic group on the surface, the carboxyl group equivalent is preferably 200 to 1200 μmol / g, more preferably 400 to 1000 μmol / g, What is 600-800 micromol / g is still more preferable.

  The concentration of the pigment (I) having an acidic group on the surface in the slurry is preferably 3 to 30% by mass, more preferably 4 to 28% by mass, and 5 to 25% by mass. Further preferred. When the concentration of the pigment (I) having an acidic group on the surface in the slurry is within the above range, the basic compound having two or more amino groups selected from a primary amino group and a secondary amino group described later in the molecule. By introducing a predetermined amount of (II) into the slurry, the reaction between the pigment and the basic compound can be easily performed.

  Although the pigment (I) having an acidic group on the surface can be obtained by the above-described method, a commercially available product can be used as the pigment having an acidic group on the surface, and is commercially available as self-dispersing carbon black. Compared to carbon black with relatively high dispersion stability such as AquaBlack (registered trademark) 162 and AquaBlack (registered trademark) 164 (both manufactured by Tokai Carbon Co., Ltd.), and these self-dispersing carbon blacks, Examples thereof include carbon black having an acidic group concentration of 50% or more and less than 100%. When a commercially available product is used as the pigment (I) having an acidic group on the surface, before the reaction with a basic compound having two or more amino groups selected from a primary amino group and a secondary amino group described later in the molecule. In addition, it is preferable to disperse in advance in an aqueous medium in which the reaction with the basic compound is performed. In this case, it is more preferable to disperse the pigment so that the pigment concentration is the same as the pigment concentration in the slurry.

  The average particle diameter of the pigment (I) having an acidic group on the surface is preferably 50 to 250 nm, more preferably 60 to 200 nm, and further preferably 70 to 150 nm. . In the present application documents, the average particle size of the pigment (I) having an acidic group on the surface is 50% of the cumulative particle size in the volume-based cumulative particle size distribution measured by a laser diffraction particle size distribution measuring device ( Mean average particle diameter D50).

  As the basic compound (II) having two or more amino groups selected from primary amino groups or secondary amino groups in the molecule, it can react with acidic groups on the surface of the pigment, and a polyisocyanate polyurethane resin (described later) If it can be urea-bonded to the terminal isocyanate group of III), it is not particularly limited. For example, aliphatics such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, 1,3-propylenediamine, and hexamethylenediamine Examples include polyvalent amines, aromatic polyvalent amines such as phenylenediamine, diaminonaphthalene, and xylenediamine, and alicyclic polyvalent amines such as piperazine, N-aminoethylpiperazine, and isophoronediamine. Multiple can be used.

  In the pigment dispersion composition of the present invention, the polyurethane resin-added pigment (A) has two or more amino groups in the molecule, the pigment (I) having an acidic group on the surface, and a primary amino group and a secondary amino group. It is prepared from a pigment having an unreacted amino group on the surface obtained by contacting the basic compound (II) in an aqueous medium.

  The aqueous medium for bringing the pigment (I) having an acidic group on the surface into contact with the basic compound (II) is preferably water, and examples of the aqueous medium other than water include acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol. A solvent that is water-soluble and does not react with amines or isocyanates, such as dimethyl ether, is preferred. Examples include glycol-based aqueous solvents such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol, dimethyl sulfoxide, sulfolane, and the like, and a mixture of two or more of these aqueous media. Also good. However, since the glycol-based aqueous solvent having an alcoholic hydroxyl group may react with the terminal isocyanate group of the polyurethane resin (III) described later, the glycol-based aqueous medium suppresses the amount used, and the polyurethane resin described later. It is preferable to add after the reaction.

  The pigment having an unreacted amino group on the surface, which is a constituent material of the polyurethane resin addition pigment (A), has a pigment (I) having an acidic group on the surface and an amino group selected from a primary amino group and a secondary amino group. It is preferable to prepare the basic compound (II) having two or more molecules in the aqueous medium by bringing them into contact with each other by stirring for 0.5 to 10 hours at a temperature of 20 to 60 ° C. .

  The addition amount of the basic compound (II) having two or more amino groups selected from a primary amino group and a secondary amino group in the molecule is such that the amino group of the basic compound (II) has a terminal isocyanate group described later of 2 The polyisocyanate polyurethane resin (III) has an isocyanate group content of 0.1 to 2 equivalent ratio (number of amino group moles of basic compound (II) / isocyanate group mole of polyisocyanate polyurethane resin (III)). The reaction is preferably carried out so that the number is 0.1-2. The equivalent ratio is more preferably 0.2 to 1.8.

  By bringing a basic compound (II) having two or more amino groups in the molecule selected from primary amino groups and secondary amino groups into contact with pigment (I) having an acidic group on the surface in an aqueous medium. The pigment can be made to be a pigment having an unreacted amino group on its surface by being ionically attracted to the acidic group on the surface of the pigment so that the basic compound is present in the vicinity of the pigment surface.

  In the pigment dispersion composition of the present invention, the polyurethane resin-added pigment (A) is obtained by contacting the pigment having an unreacted amino group on the surface with a polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups. It can be produced by bonding.

  The amino group on the pigment surface and the isocyanate group of the polyisocyanate polyurethane resin (III) react instantaneously to form a urea bond. For this reason, cross-linking and chain elongation of the polyisocyanate polyurethane resin (III) occurred on the pigment surface, resulting in chemical bonding and physical adhesion to the pigment surface, and the surface was coated with the polyisocyanate polyurethane resin (III). A polyurethane resin addition pigment (A) can be obtained.

  The polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups is not particularly limited as long as the terminal isocyanate group can form a urea bond with the amino group present on the pigment surface.

  The polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups has a functional group or molecular chain having a function capable of being dispersed in an aqueous medium in the molecule in order to react with the amino group on the surface of carbon black. And a polyurethane resin obtained by urethane-bonding a compound having two or more hydroxyl groups and a polyisocyanate compound.

  As a compound having two or more hydroxyl groups having a functional group or a molecular chain that can be dispersed in an aqueous medium in the molecule, a compound having a functional group capable of forming a salt that causes phase inversion of the polyurethane resin in the aqueous medium. Preferable examples include tertiary carboxyl group-containing polyol compounds.

  Examples of the tertiary carboxyl group-containing polyol compound include polyhydroxycarboxylic acids such as dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolacetic acid, dimethylolbutyric acid, dimethylolvaleric acid, and dimethylolcaproic acid. Of these, dihydroxymonocarboxylic acids such as dimethylolpropionic acid and dimethylolbutanoic acid are preferred. Since the tertiary carboxyl group of the above compound has extremely low reactivity with the isocyanate compound, the target polyurethane resin can be efficiently produced without inhibiting the urethane bond reaction.

  Moreover, it is possible to control the acid value of the resulting polyurethane resin by controlling the blending amount of the above-mentioned tertiary carboxyl group-containing polyol compound. In order to adjust the acid value, a tertiary carboxyl group containing In addition to the polyol compound, a diol compound having a nonionic molecular chain can be used. The diol compound having a nonionic molecular chain is typified by polyethylene glycol diol (PEG) or a copolymer diol of polyethylene glycol diol (PEG) and polypropylene glycol diol (PPG) or polybutylene glycol diol (PBG). Mention may be made of polyalkylene glycol diols.

  A polyol having at least two hydroxyl groups in the molecule can be used in an arbitrary ratio together with a tertiary carboxyl group-containing polyol compound or a diol compound having a nonionic molecular chain.

  As the polyol having at least two hydroxyl groups in the molecule, side chain modified diols or the like chemically modified according to the purpose by reaction such as Michael addition can be used, and various hydrophobic groups and hydrophilic groups can be used in the side chain. Introducing can make a wide range of hydrophilic and hydrophobic balance designs in the resulting polyurethane resin (III).

  The side chain-modified diol can be synthesized by an addition reaction between a dialkanolamine and a (meth) acrylic acid derivative. The reaction such as Michael addition is preferable because the addition reaction with a highly reactive acrylic acid derivative is easier to control than the reaction between a dialkanolamine and a methacrylic acid derivative. Examples of dialkanolamines include dihydroxyamine substitution of secondary amines such as diethanolamine, dipropanolamine, and diisopropanolamine, and (meth) acrylic acid derivatives are not particularly limited. For example, (meth) acrylic acid alkyl esters, (Meth) acrylic acid cycloalkyl ester, (meth) acrylic acid substituted aromatic ester, (meth) acrylic acid halogenated alkyl ester, (meth) acrylic acid ester, aromatic vinyl compound, vinyl cyanide compound, unsaturated dibasic There may be mentioned acids or their derivatives.

  Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like.

  Examples of the (meth) acrylic acid cycloalkyl ester include cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, and the like. It is done.

  Examples of the (meth) acrylic acid aromatic ester include phenyl (meth) acrylate, benzyl (meth) acrylate, and the like.

  Examples of the (meth) acrylic acid halogenated alkyl ester include fluoromethyl (meth) acrylate, fluoroethyl (meth) acrylate, and the like.

  Examples of the (meth) acrylic acid ester include (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid glycidyl, (meth) acrylic acid ethylene glycol ester, (meth) acrylic acid polyethylene glycol ester, and the like.

  Examples of the aromatic vinyl compound include α-substituted styrene such as styrene, α-methylstyrene, and α-ethylstyrene, and nucleus-substituted styrene such as fluorostyrene and methylstyrene.

  Other (meth) acrylic acid derivatives include aliphatic monoacrylates such as 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate Monoacrylate having an alicyclic structure such as isobornyl (meth) acrylate; benzyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate , Aromatic monoacrylates such as nonylphenoxyethyl (meth) acrylate and nonylphenoxytetraethylene glycol (meth) acrylate; Alkyl ether acrylates such as glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, butoxyethyl (meth) acrylate, butoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate; 2- (meth) acryloyloxy Dibasic acid mono (meth) acryloyloxy such as ethyl hydrogen succinate, 2- (meth) acryloyloxyethyl hydrogen hexahydrophthalate, 2- (meth) acryloyloxyethyl hydrogen phthalate, 2- (meth) acryloyloxypropyl hydrogen phthalate Esters: Mono 2-ethylhexyl ether polyoxyethylene glycol (meth) acrylate, monononyl phenyl ether Monoalkyl ether polyoxyalkylene glycol (meth) acrylates such as polyoxyethylene glycol (meth) acrylate, mono 2-ethylhexyl ether polyoxypropylene glycol (meth) acrylate, monononylphenyl ether polyoxypropylene glycol (meth) acrylate; polyethylene Monoacrylates having polyoxyethylene ether bonds such as glycol mono (meth) acrylate and polypropylene glycol mono (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate 2-hydroxy-3-butoxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate Mono (meth) acrylate having hydroxyl group such as ε-caprolactone adduct of 2-hydroxyethyl (meth) acrylate; alicyclic ether (meth) acrylate such as glycidyl (meth) acrylate and tetrahydrofurfuryl (meth) acrylate Nitrogen-containing N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, morpholino (meth) acrylate, N, N-dimethylacrylamide, dimethylaminopropyl acrylate, N-isopropylacrylamide, etc. Polyoxyalkylene phosphate mono (meth) acrylates such as monoacrylate, polyoxyethylene phosphate mono (meth) acrylate, polyoxypropylene phosphate mono (meth) acrylate And the like.

  Examples of the polyol having at least two hydroxyl groups in the molecule include ethylene glycol, propylene glycol, cyclohexane-1,4-dimethanol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, 1, 6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,8- Examples thereof include diols such as octanediol, 1,9-nonanediol, and cyclohexyldimethanol, and polymer polyols.

  Examples of the polymer polyol include polyester polyol such as polyester diol, polymer diol such as polycarbonate diol, polylactone diol, and polybutadiene diol, and polyether polyol. In addition, a polymer diol of a compound having a rosin skeleton or a hydrogenated rosin skeleton can be given. The molecular weight of the polymer polyol is preferably in the range of 300 to 5000 in terms of number average molecular weight, and more preferably in the range of 500 to 3000 in terms of number average molecular weight.

  The polyester polyol is obtained by a condensation reaction of one or more of the following polyols and polyol synergistic components with one or more of polybasic acids and their anhydrides. Things.

  Examples of the raw material polyol for polyester polyol include ethylene glycol, propylene glycol, cyclohexane-1,4-dimethanol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, 1,6-hexanediol. 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,8-octanediol, , 9-nonanediol, cyclohexanedimethanol, bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, castor oil-modified diol, castor oil-modified polyol, and the like.

  Polyol equivalent ingredients that are raw materials for polyester polyols include alkyl monoglycidyl ethers such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, lauryl glycidyl ether, decyl glycidyl ether and stearyl glycidyl ether, and alkyl glycidyl esters (product names). One or more of monoepoxy compounds such as Cardura E10 (manufactured by Shell Japan Co., Ltd.) can be mentioned.

  Polybasic acids and their anhydrides that are raw materials for polyester polyols include aliphatic dibasic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and dimer acid, and their anhydrides, dodecenyl succinic anhydride, Aromatic polybasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid and trimellitic anhydride, and anhydrides thereof, alicyclic polybasic acids such as hydrophthalic anhydride and dimethyl-1,4-cyclohexanedicarboxylic acid, and the like The anhydride of these is mentioned.

  As the polylactone diol, a polyester polyol obtained by ring-opening addition polymerization of a monomer having a lactone ring such as ε-caprolactone or β-methyl-δ-valerolactone, starting from a hydroxyl-terminated compound such as the above polyol or the above polyester polyol. Are also examples of polyester polyols.

  Examples of the polycarbonate diol include 1,4 butanediol, 1,6 hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, and 2-butyl-2-ethyl-1,3. -Polycarbonate diols using diols such as propanediol, 1,9-nonanediol and 2-methyl-1,8-octanediol as raw materials.

  As polybutadiene diol, the following formula:

(However, k = 0.2, l = 0.2, m = 0.6, and n is a positive integer.) Polybutadienediol Poly bdR-15HT, R-45HT represented by Idemitsu Kosan Co., Ltd. ), Polyisoprene diol Poly ip (made by Idemitsu Kosan Co., Ltd.), and the following formula

(In the formula, n represents a positive integer.)
Α, ω-polybutadiene glycol G-1000, G-2000, G-3000 (manufactured by Nippon Soda Co., Ltd.) and the like represented by

  Polyether polyols include polyethylene glycol diol (PEG), polypropylene glycol diol (PPG), polyalkylene glycols represented by polybutylene glycol diol (PBG), bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol. Starting from F or the like, polyether polyols to which propylene oxide, tetrahydrofuran, or butylene oxide is added may be mentioned.

  Examples of the polymer diol of the compound having a rosin skeleton or a hydrogenated rosin skeleton include Pine Crystal D-6011 and D-6240 (manufactured by Arakawa Chemical Industries).

  On the other hand, the polyisocyanate compound is not particularly limited as long as it contains two or more isocyanate groups in the molecule. Depending on the purpose, a diisocyanate compound or a polyisocyanate compound containing three or more isocyanate groups may be used.

  Examples of the diisocyanate compound include diphenylmethane diisocyanate (hereinafter abbreviated as MDI), polyphenylene polymethylene polyisocyanate, tolylene diisocyanate (hereinafter abbreviated as TDI), xylylene diisocyanate, tetramethylxylylene diisocyanate, and isophorone diisocyanate (hereinafter abbreviated as IPDI). Hexamethylene diisocyanate (hereinafter abbreviated as HDI), tetramethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, etc. Of the isocyanate group of the compound having an isocyanate group of Part biuret, allophanate, carbodiimide, uretonimine, oxazolidone, amide, imide, isocyanurate, include those obtained by modifying the uretdione or the like. These may be used alone or in combination of two or more as required.

  When the isocyanate group of the polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups reacts with the basic compound (II) having two or more amino groups in the surface of the pigment (I) dispersed in water. In addition, it becomes a competitive reaction between water and amino groups. The diisocyanate compound is preferably a non-aromatic diisocyanate compound having a slower reaction rate with water than the isocyanate group of an aromatic diisocyanate compound such as MDI or TDI, and in particular, an aliphatic diisocyanate represented by IPDI or hydrogenated MDI. By using an aliphatic diisocyanate represented by a compound or 1,6-hexamethylene diisocyanate at the molecular end, the reaction of the basic compound (II) having two or more amino groups in the molecule with the polyisocyanate polyurethane resin (III) Can be prioritized. Further, by setting the reaction temperature at this time to 50 ° C. or less, preferably within 25 to 40 ° C., a further difference in reaction rate occurs, giving priority to the reaction between the basic compound (II) and the polyisocyanate polyurethane resin (III). Can do.

  In order to prepare a polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups by urethane-bonding a polyol compound having at least two hydroxyl groups in the molecule, a diisocyanate compound, and a polyisocyanate, A compounding ratio in which the number of equivalents of isocyanate groups of the diisocyanate compound is 2 equivalents or more relative to the number of equivalents of hydroxyl groups in the compound having two hydroxyl groups (when a diol compound is used as the compound having at least two hydroxyl groups in the molecule) , A polyurethane resin having isocyanate groups at both ends can be obtained. A method of increasing the molecular weight by synthesizing isocyanate-terminated oligomers in multiple stages is also useful because an isocyanate-terminated polymer can be obtained with high accuracy and a polyurethane resin with little variation in molecular weight distribution can be obtained.

  In order to obtain the above polyurethane resin, taking the reaction of a compound having two hydroxyl groups in the molecule and a diisocyanate compound as an example, when the total number of moles of diol is n in an organic solvent, the total number of moles of diisocyanate By reacting so as to be (n + 1), a polyurethane having a terminal isocyanate group can be synthesized.

  The polyisocyanate polyurethane resin (III) preferably has a solid content acid value of 20 to 200 mgKOH / g, more preferably 25 to 150 mgKOH / g, and more preferably 30 to 120 mgKOH in order to give a function of dispersing in water. More preferably, it is / g.

  The acid value can be adjusted by adjusting the number of moles of the tertiary carboxyl group-containing diol compound.

  In this application, a tertiary carboxyl group-containing diol compound is used as a compound having a functional group or molecular chain dispersible in an aqueous medium in the molecule and having two or more hydroxyl groups, and a diisocyanate compound is used as a polyisocyanate compound. The acid value (AN) of the polyisocyanate polyurethane resin (III) is calculated by the following formula.

(In the above formula, a1: mole number of a tertiary carboxyl group-containing diol compound such as dimethylolpropionic acid, A1: molecular weight of a tertiary carboxyl group-containing diol compound such as dimethylolpropionic acid, a2, a3... an: number of moles of other diols, A2, A3... An: molecular weight of other diols, b1, b2, b3... bn: number of moles of diisocyanate, B1, B2, B3. Molecular weight.)

  The number average molecular weight of the polyisocyanate polyurethane resin (III) when a diol compound is used as the polyol and a diisocyanate compound is used as the polyisocyanate compound can be calculated and adjusted by the following formula.

Number average molecular weight = nA ′ + (n + 1) B ′
(However, in the above formula, n is the total number of moles of polyols, A ′ is the number average molecular weight of polyols, and B ′ is the number average molecular weight of diisocyanate.)

  The polyisocyanate polyurethane resin (III) thus obtained has a number average molecular weight calculated by the above formula of preferably 1000 to 15000, more preferably 1300 to 10000, and 1600 to 8000. More preferably it is. The polyisocyanate polyurethane resin (III) preferably has a solid content acid value of 20 to 200 mgKOH / g, more preferably 25 to 150 mgKOH / g in order to give a function of dispersing in water. More preferably, it is -120 mgKOH / g.

  When a polyurethane resin is prepared using a polyol or polyisocyanate compound that is more than bifunctional as the polyol, the P.I. J It is desirable to adjust the molar fraction with reference to the Flory gelation formula to prevent gelation.

  When obtaining the polyisocyanate polyurethane resin (III), the reaction temperature between the polyols and the polyisocyanate compound is preferably 60 to 80 ° C. from the viewpoint of suppressing side reactions, and is usually solvent-free or is usually ethyl acetate, methyl ethyl ketone, acetonitrile or the like. It can react using the well-known and arbitrary organic solvents used for a urethane reaction. As the urethane reaction catalyst, any known catalyst such as a tertiary amine catalyst, dibutyltin laurate, stannous octylate and the like can be used. It can react even without catalyst.

  When the polyurethane resin having a terminal isocyanate group is composed of a tertiary carboxyl group-containing polyol compound or the like, triethylamine, trimethylamine, N-methyl is appropriately used when the polyurethane resin is phase-inverted into an aqueous medium liquid. It is preferable to add a tertiary amine such as morpholine, tributylamine, N-methylpyrazine, or methylimidazole.

  In order to prepare a polyurethane resin-added pigment (A), when a urea reaction is caused by contacting a pigment having an unreacted amino group on the surface with a polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups, an unreacted amino group is formed on the surface. It is preferable to add 2-200 mass parts of polyisocyanate polyurethane resin (III) with respect to 100 mass parts of pigments which have group, and it is more preferable to add 10-100 mass parts. When the addition amount is less than 2 parts by mass, the effect of improving the image density cannot be obtained. When the addition amount exceeds 80 parts by mass, the polyurethane resin becomes excessive and the image density and storage stability are lowered.

  When the isocyanate group of the polyisocyanate polyurethane resin (III) reacts with a pigment having an unreacted amino group on the surface, the reaction temperature is preferably 50 ° C. or less, more preferably 25 to 40 ° C. By making the reaction temperature within the above range, a reaction rate difference is generated, and the reaction between the unreacted amino group present on the pigment surface and the polyisocyanate polyurethane resin (III) is changed as a side reaction between the polyisocyanate polyurethane resin (III) and water. Preference can be given to the reaction with the solvent.

  In this way, by reacting the unreacted amino group on the pigment surface with the terminal isocyanate group of the polyurethane resin to form a urea bond, the polyurethane resin that exhibits the effect as a dispersant on the pigment surface is physically and chemically treated. Can be combined.

  In general, the self-dispersing pigment, that is, the pigment (I) having an acidic group on the surface, when neutralized by counter ions, the pigment particles are dispersed by repulsion of ions, and when the polymer is added to the surface, its storage stability However, when the concentration of acidic groups on the pigment surface is low, dispersion stability is lacking. On the other hand, the polyurethane resin-added pigment (A) used in the present invention is a polyisocyanate polyurethane resin having two or more terminal isocyanate groups on the surface (especially when the acidic group concentration on the surface of the pigment (I) is low) ( By adding (III) via a urea bond, excellent dispersibility and dispersion stability can be exhibited.

  The pigment dispersion composition of the present invention preferably contains 5 to 150% by mass of the polyurethane resin-added pigment (A), more preferably 6 to 120% by mass, in terms of solid content, more preferably 7 to 100%. More preferably, the content is 1% by mass.

The pigment dispersion composition of the present invention contains an aqueous dispersion resin (B) having an average particle diameter of 10 to 300 nm.
The aqueous dispersion resin (B) is a self-dispersing aqueous dispersion resin having an anion group or a nonion group in the molecule, or an emulsifier dispersion type aqueous dispersion resin dispersed by an anionic emulsifier and / or a nonionic emulsifier. Preferably there is.
Examples of the aqueous dispersion resin (B) include a self-dispersion aqueous dispersion in which an anion such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group is contained in the resin molecular chain and a part or all of the anion is neutralized with a counter ion. Self-dispersing aqueous dispersion resin in which resin, resin having nonionic hydrophilic group such as polyoxyethylene ether chain in side chain and main chain is dispersed in water, and emulsifier dispersed in water by anionic emulsifier and / or nonionic emulsifier Examples thereof include a dispersion-type aqueous dispersion resin and an emulsifier-dispersion-type aqueous dispersion resin having an anion or nonionic group in the molecule and obtained by dispersing the emulsifier.
The aqueous dispersion resin (B) is preferably dispersed in an aqueous medium such as water, and examples of the aqueous medium include the same ones as described above.

More specifically, as the aqueous dispersion resin (B), self-emulsification of acrylic emulsion, latex, aqueous resin, and the like, and a water dispersion resin having self-dispersibility, and a monomer constituting these resins are emulsified with an emulsifier. Examples thereof include a polymerization water-dispersed resin obtained by dispersing to form particles and polymerizing in the particles.
In addition, self-dispersing and self-emulsifying resins such as epoxy ester resins, vinyl-modified epoxy resins, high acid value alkyd resins, vinyl-modified aqueous alkyd resins, water-based polyester resins, and water-based polyurethane resins, and using these resins as emulsifiers Examples thereof include a core-shell type obtained by forming particles and polymerizing different monomers in the particles.

Polymeric water-dispersed resins include crotonic acid and itaconic acid. Vinyl polymerizations such as fumaric acid, maleic acid and other unsaturated groups and their esters, styrene, vinyl acetate, versatic acid vinyl ester, (meth) acrylic acid, (meth) acrylic acid ester, sodium styrene sulfonate And those obtained by copolymerization of the functional monomer.
Examples of the emulsion-type polymerized water-dispersed resin include those in which the above-mentioned polymerized water-dispersed resin is contained in an emulsifier.

  The epoxy ester resin has a carboxyl group in the molecule obtained by reacting an acid anhydride with an epoxy ester obtained by reacting an epoxy group of an epoxy resin with a fatty acid having an unsaturated double bond with a hydroxyl group. Examples thereof include those obtained by neutralizing a polymer with a counter ion.

  As the vinyl-modified epoxy resin, a vinyl polymerizable monomer is used for the unsaturated double bond of the fatty acid of the epoxy ester resin obtained by reacting the fatty acid having an unsaturated double bond with the epoxy group or hydroxyl group of the epoxy resin. Mention may be made of vinyl-modified epoxy ester resins obtained by copolymerization.

  Examples of the high acid value alkyd resin include those obtained from a condensation reaction product of a polycarboxylic acid compound obtained by acidolysis of a polybasic acid and an oil and a monoalcohol, diol, or polyol.

  As the vinyl-modified aqueous alkyd resin, the polymerization described above is performed for the unsaturated double bond in the oil and fat component of the alkyd resin produced by condensation of a polybasic acid with a compound obtained by alcoholysis of polyhydric alcohol and fat. The thing obtained by copolymerizing the vinyl polymerizable monomer used as the raw material of the aqueous dispersion resin can be exemplified.

  As an aqueous polyester resin, for example, a dialkanol alkanoic acid such as dimethylolpropionic acid or dimethylolbutanoic acid having a hydroxyl group and a tertiary carboxyl group in the molecule is reacted with a dibasic acid as a part of the diol component. Things can be mentioned.

  The water-based polyester resin is a polyoxyethylene ether glycol for introducing a hydrophilic group, a tertiary carboxyl group-containing polyol compound or polyol, one or more selected from polyol effective components, polybasic acids, anhydrides thereof, and the like. It can also be obtained by condensation reaction with one or more, and the polyester in which an acid is introduced into the molecular chain can be neutralized with a counter ion.

  Examples of the tertiary carboxyl group-containing polyol compound of the aqueous polyester raw material include polyhydroxycarboxylic acids such as dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolacetic acid, dimethylolbutyric acid, dimethylolvaleric acid, and dimethylolcaproic acid. Of these, dihydroxymonocarboxylic acids such as dimethylolpropionic acid and dimethylolbutanoic acid are preferred.

  Examples of the polyol used as a raw material for the aqueous polyester include ethylene glycol, propylene glycol, cyclohexane-1,4-dimethanol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, 1,6 -Hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,8-octane Examples thereof include diol, 1,9-nonanediol, cyclohexanedimethanol, bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, castor oil-modified diol, castor oil-modified polyol, and the like.

  Polyol synergistic components used as raw materials for polyesters include alkyl monoglycidyl ethers such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, lauryl glycidyl ether, decyl glycidyl ether and stearyl glycidyl ether, and alkyl glycidyl esters (product name Cardura E10). : Manufactured by Shell Japan Co., Ltd.) or other monoepoxy compounds.

  Polybasic acids and their anhydrides that are raw materials for the above-mentioned aqueous polyester include aliphatic dibasic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and dimer acid, and their anhydrides, dodecenyl succinic anhydride, Aromatic polybasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid and trimellitic anhydride, and anhydrides thereof, alicyclic polybasic acids such as hydrophthalic anhydride and dimethyl-1,4-cyclohexanedicarboxylic acid, and the like The anhydride of these is mentioned.

The emulsifier-dispersed aqueous dispersion resin used as the aqueous dispersion resin (B) is an emulsion-type polymerized water-dispersed resin obtained by emulsifying or dispersing a resin monomer with an emulsifier to form particles and polymerizing within the particles. Examples thereof include a core-shell type emulsion in which a resin called self-dispersion type or self-emulsification type is used as an emulsifier to polymerize and form different polymers in the particles.
The emulsifier is preferably at least one selected from an anionic emulsifier and a nonionic emulsifier.

  In the pigment dispersion composition of the present invention, the average particle diameter of the aqueous dispersion resin (B) is 10 to 300 nm, preferably 20 to 250 nm, and more preferably 30 to 200 nm.

  In the present application documents, the volume average particle size of the aqueous dispersion resin (B) is 50% mode diameter (50% in cumulative particle size in the volume reference cumulative particle size distribution) measured by a dynamic light scattering particle size distribution analyzer. Particle size (average particle size D50)).

  By including the aqueous dispersion resin (B) together with the polyurethane resin addition pigment (A), the pigment dispersion composition of the present invention can improve coating film performance such as scratch resistance and marker resistance.

  The pigment dispersion composition of the present invention preferably contains 1 to 80% by mass of the aqueous dispersion resin (B) in terms of solid content, more preferably 3 to 65% by mass, and 5 to 50% by mass. Further preferred.

  The pigment dispersion composition of the present invention, together with the polyurethane resin-added pigment (A) and the aqueous dispersion resin (B), is a known arbitrary moisturizer, preservative, emulsifier, pH adjuster, antifoaming agent, coating film surface smoothing agent, etc. Or a water-soluble resin, a wax dispersed in water, a resin emulsion, or the like.

  Examples of the humectant include one or more selected from polyoxyalkylene ether glycols such as glycerin, diethylene glycol, triethylene glycol, and dipropylene glycol, or monoalkyl ethers and dialkyl ethers of polyoxyalkylene ether glycols.

  The pigment dispersion composition of the present invention, for example, while adding a polyurethane resin addition pigment (A) and an aqueous dispersion resin (B) while stirring in a stirring container, further known arbitrary moisturizer, preservative, emulsifier, Add additives such as pH adjuster, antifoaming agent, coating surface smoothing agent, water-soluble resin, wax dispersed in water, resin emulsion, etc., stir, and if necessary with water, water-soluble organic solvent It can manufacture by adjusting a viscosity and filtering by the well-known arbitrary filtration methods.

  In the pigment aqueous dispersion composition of the present invention, the pigment concentration, that is, the mass ratio of the pigment (I) in the composition can be appropriately selected according to the type of pigment and the intended use of the pigment dispersion composition. When it is used as an ink jet ink composition using a carbon black pigment, it can be 2 to 15% by mass.

Next, the inkjet ink composition of the present invention will be described.
The ink-jet ink composition of the present invention is characterized by comprising the pigment dispersion composition of the present invention.
The inkjet ink composition of the present invention is the same as the pigment dispersion composition of the present invention except that its application is limited to inkjet ink applications, and the details thereof are the same as those described above.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

  The contents of the present invention will be described below with specific examples. However, the present invention is not limited to the contents of these examples.

(Preparation of low oxidation carbon black pigment A)
Nitrogen adsorption specific surface area of 170m ² / g, and 100g of carbon black a DBP absorption amount is 115cm ³ / 100g, 0 per the carbon black unit surface area. An aqueous solution prepared by dissolving sodium peroxodisulfate (Na ₂ S ₂ O ₈ ) weighed by the following formula 1 so as to react at 10 mmol / m ² in pure water to ³ dm ³ was added to the reaction vessel, and the reaction was performed. Temperature 60 ° C., reaction time 10 hours, stirring speed 0. Oxidized with 12s ^-1 .
Next, the oxidized carbon black was filtered, dispersed in pure water, and neutralized with an aqueous sodium hydroxide solution. After neutralization, the carbon black slurry was treated with a centrifuge (CR22F manufactured by Hitachi Koki Co., Ltd.) at a rotation speed of 7.5 × 10 ⁻³ s ^{−1 for} 15 minutes. Thereafter, the remaining salt is separated and purified from the obtained supernatant with an ultrafiltration membrane (AHP-1010 manufactured by Asahi Kasei Co., Ltd., molecular weight cut off 50000) so that the carbon black dispersion concentration becomes 20% by mass. The water was removed to obtain an aqueous dispersion of low oxidation carbon black A.
(Formula 1) Required amount of sodium peroxodisulfate (mg) = required number of moles of sodium peroxodisulfate per unit area of carbon black (mmol / m ² ) × specific surface area of carbon black (m ² / g) × carbon Calculate according to the amount of black (g) × equivalent sodium peroxodisulfate (238.1 g / mol).
For example, the mass of sodium peroxodisulfate necessary for treating 100 g of carbon black a is 0.10 (mmol / m ² ) × 170 (m ^{2 /} g) × 100 (g) × 238.1 (g / Mol) = 404770 (mg) = 404.77 (g).

(Preparation of polymer-added carbon black pigment dispersion 1)
(1) Synthesis of side chain diol Light acrylate NP-4EA (nonylphenyl tetraethylene ether glycol acrylate) manufactured by Kyoeisha Chemical Co., Ltd. with respect to 190 parts of N, N′-diethanolamine in a flask equipped with a stirring bar, a dry nitrogen blowing tube and a cooling tube ), And after reacting at 80 ° C. for 7 hours, a diol having a nonylphenyl chain in the molecular side chain (hereinafter referred to as diol LKG-1) was obtained. The quotient of tertiary amine value / total amine value of the reaction product was 0.98 or more.

(2) Synthesis of isocyanate-terminated aqueous polyurethane 60.4 parts by mass of dimethylol butanoic acid with respect to 400 parts by mass of methyl ethyl ketone (MEK) in a flask equipped with a stirrer, a nitrogen gas blowing tube, and a ball cooling tube .6 molar ratio], 96.1 parts by weight of castor oil-modified diol HS-2G-160R (manufactured by Toyokuni Oil) [0.8 molar ratio], Kuraray polyester diol P-2050 (number average molecular weight 2066, manufactured by Kuraray Co., Ltd.) 129.7 parts by mass [0.4 mol ratio], 104.5 parts by mass [1.2 mol ratio] of the diol LKG-1 obtained in the above (1), and 209.3 parts by mass [6 mols] isophorone diisocyanate. Ratio] was added, and the mixture was reacted at 65 ° C. for 7 hours. The mass% of isocyanate groups in the reaction solution at this time was 1.35% by mass, and the solid content acid value was 38 mgKOH / g.
After the above reaction, the mixture was cooled to 35 ° C., 41.2 parts by mass of triethylamine was further added, and the mixture was stirred for 30 minutes, so that the nonvolatile content was 58% by mass, Gardner bubble viscosity: JK, GPC number average molecular weight 1790, weight average. An isocyanate-terminated aqueous polyurethane (hereinafter referred to as polyurethane resin 1) having a molecular weight of 5550 and a ratio of the number of moles of OH groups to the number of moles of NCO groups (number of moles of OH groups / number of moles of NCO groups) was 5/6.

(3) Preparation of polymer-added aqueous pigment dispersion As pigment (I), AquaBlack (registered trademark) 162 which is a carbon black having an acidic group on the surface (made by Tokai Carbon Co., Ltd., solid content concentration: 19.2% by mass, carboxyl group) Equivalent: 800 micromol / g) 1 kg of 41.3 g of 5% aqueous solution of piperazine.6H ₂ O (Mw = 194) as basic compound (II) was added, stirred at room temperature for 30 minutes, and then polyisocyanate polyurethane As the resin (III), 66.2 g of the polyurethane resin 1 (solid content: 58.0% by weight) obtained in the above (2) was added, stirred at room temperature for 3 hours, and further stirred at 40 ° C. for 1 hour. Thereafter, the reaction solvent (MEK) was distilled off under reduced pressure to obtain a polymer-added aqueous pigment dispersion (hereinafter referred to as polymer-added carbon black pigment dispersion 1) having a nonvolatile content of 24%. In the obtained polymer-added aqueous pigment dispersion 1, the mass ratio of carbon black having acidic groups on the surface relative to the polyurethane resin 1 (carbon black / polyurethane resin) was 100/20 in terms of solid content.

(Preparation of polymer-added carbon black pigment dispersion 2)
(1) Synthesis of isocyanate-terminated aqueous polyurethane 65 parts by mass of dimethylolpropionic acid with respect to 200 parts by mass of methyl ethyl ketone (MEK) in a flask equipped with a stirring bar, a nitrogen gas blowing tube, and a ball cooling tube [2.8 molar ratio ], 203 parts by mass [5.3 molar ratio] of isophorone diisocyanate (Sumika Bayer Urethane Dismodule) was added and reacted at 65 ° C. for 6 hours.
Further, castor oil-modified diol HS-2G-150 (manufactured by Toyokuni Oil Co., Ltd., number average molecular weight 765.3) 66 parts by mass [0.5 molar ratio], Kuraray polyester diol P-2050 (number average molecular weight 2066, Kuraray Co., Ltd.) 178 parts by mass [0.5 molar ratio], polyethylene ether glycol # 1000 (manufactured by NOF Corporation, number average molecular weight 1002) 88 parts by mass [0.5 molar ratio], and 200 parts by mass of MEK. For 3 hours. The mass% of isocyanate groups in the reaction solution at this time was 1.45% by mass, and the solid content acid value was 45 mgKOH / g.
After the above reaction, the mixture was cooled to 35 ° C., 39.1 parts by mass of N-methyl morpholine was added, and the mixture was stirred for 30 minutes, whereby the non-volatile content was 60.2% by mass, the Gardner bubble viscosity: TU, GPC number An isocyanate-terminated aqueous polyurethane having an average molecular weight of 3400, a weight average molecular weight of 7800, and a ratio of the number of moles of OH groups to the number of moles of NCO groups (number of moles of OH groups / number of moles of NCO groups) is 4.3 / 5.3 And polyurethane resin 2).

(2) Preparation of polymer-added aqueous pigment dispersion As a pigment (I), an aqueous dispersion of low oxidation carbon black A in which the degree of oxidation of AquaBlack (registered trademark) 162, which is carbon black having acidic groups on the surface, is lowered (solid) 55.6 g of 5% aqueous solution of piperazine · 6H ₂ O (Mw = 194) as basic compound (II) was added to 1 kg of the partial concentration 20.0% by mass, carboxyl group equivalent: 600 μmol / g), After stirring at room temperature for 30 minutes, 83.1 g (solid content 50 g) of the polyurethane resin 2 (solid content 60.2% by mass) obtained in the above (1) was added as polyisocyanate polyurethane resin (III), and the mixture was stirred at room temperature for 3 hours. After stirring, the mixture was further stirred at 40 ° C. for 1 hour. Thereafter, the reaction solvent (MEK) was distilled off under reduced pressure to obtain a polymer-added aqueous pigment aqueous dispersion (hereinafter referred to as polymer-added carbon black pigment dispersion 2) having a nonvolatile content of 25%.
In the obtained polymer-added carbon black pigment dispersion 2, the mass ratio (carbon black / polyurethane resin) of carbon black having acidic groups on the surface relative to the polyurethane resin 2 was 100/25 in terms of solid content.

(Example 1 to Example 6)
The above-mentioned polymer-added carbon black pigment dispersion 1 and polymer-added carbon black pigment dispersion 2 are used as the polyurethane resin-added pigment (A), and AE-986B (manufactured by JSR, self-dispersing type) is used as the aqueous dispersion resin (B). Acrylic emulsion; average particle size 55 nm), Hydran AP-40F (manufactured by DIC, polyurethane resin dispersion; average particle size 20 nm), Polymeron E100 (Arakawa Chemical Industries, rosin-modified styrene maleic acid resin dispersion; average particle size 100 nm) ),
Using Boncoat DV-961 (manufactured by DIC, silica-acrylic resin emulsion; average particle size 130 nm), the mixture was added into the stirring vessel with stirring so as to have the compounding ratio shown in Table 1, and glycerin and surfactant were further added. (Shinfin Chemical's Surfynol 104E), an amine compound (triethanolamine), and ion-exchanged water were added so as to have the composition shown in Table 1 and stirred to prepare each pigment dispersion composition.
In the pigment dispersion compositions obtained in Examples 1 to 4, the mass ratio of the pigment (I) to the total amount of the polyisocyanate polyurethane resin (III) and the aqueous dispersion resin (B) (the pigment (I) The mass / total of the masses of the polyisocyanate polyurethane resin (III) and the aqueous dispersion resin (B) is 100/40, and in the pigment dispersion compositions obtained in Examples 5 to 6, the above mass All ratios were 100/45.

(Comparative Examples 1 to 6)
As a pigment dispersion, AquaBlack (registered trademark) 162 (manufactured by Tokai Carbon Co., Ltd., solid content concentration: 19.2 mass%, carboxyl, used for the preparation of the above polymer-added carbon black pigment dispersion 1 and polymer-added carbon black pigment dispersion 2 Group equivalent: 800 micromol / g) and an aqueous dispersion of low oxidation carbon black A with reduced oxidation degree of AquaBlack (registered trademark) 162 (solid content concentration 20.1 mass%, carboxyl group equivalent: 600 micromol / g) and using the above AE-986B, Hydran AP-40F, Polymeron E100, Boncoat DV-961 as an aqueous dispersion resin, and while stirring in a stirring vessel so as to have the compounding ratio shown in Table 2, Furthermore, glycerin, surfactant (Shinfin Chemical Surfinol 104E), amine compound (Triethanolamine), to produce a deionized water and stirred was added so as to have the composition shown in Table 2 each pigment dispersion composition.
In the pigment dispersion compositions obtained in Comparative Examples 1 and 2, the mass ratio of the pigment to the amount of the aqueous dispersion resin (the mass of the pigment / the mass of the aqueous dispersion resin) is 100/40. In the pigment dispersion composition obtained in Comparative Example 4, the mass ratio was 100/20.

<Image density evaluation>
To each pigment dispersion composition obtained in Examples 1 to 6 and Comparative Examples 1 to 5, ion-exchanged water was added to prepare each so as to have a pigment concentration of 15% by mass. It was a thing.
The obtained ink-jet ink composition is filled in each ink cartridge, printed by an ink-jet printer EM-930C (manufactured by Seiko Epson Corporation), and a plain paper image sample is taken as a reflection type optical color densitometer (Nippon Hakusho Kaisha X-). Image density evaluation was performed by evaluating the OD average value measured by X-Rite 504) manufactured by Rite Inc. according to the following criteria. The results are shown in Table 3 and Table 4.
○: OD value: 1.4 or more △: OD value: 1.3 or more and less than 1.4 ×: OD value: less than 1.3

<Storage stability evaluation>
The ink-jet ink composition whose concentration is adjusted to 15% by mass is placed in a closed glass bottle, stored in an incubator at 70 ° C. for 3 to 4 weeks, and the viscosity (mPa · s) and particle size (nm) before and after the test are measured. The storage stability was evaluated according to the following criteria. The results are shown in Table 3 and Table 4.
A: The rate of change is in the range of -5% to + 5% until four laps have elapsed.
○: The rate of change is in the range of -5% to + 5% until the lapse of 3 laps.
(Triangle | delta): Although the change rate at the time of three laps passes is out of the range of -5%-+ 5%, it exists in the range of -10%-+ 10%.
X: The rate of change after the lapse of 3 laps is outside the range of -10% to + 10%.

<Resolubility>
Drop one drop of the ink-jet ink composition prepared at a concentration of 15% by mass onto a Teflon (registered trademark) sheet, dry it at 50 ° C. for 1 hour with an incubator, rinse it with ion-exchanged water, and check whether the trace of the dropped ink remains. Observed, re-solubility was evaluated according to the following criteria. The same evaluation was performed four times for each inkjet ink composition, and the results of confirming repeatability are shown in Tables 3 and 4.
○: No traces are visible Δ: Traces of traces exceed 0% and remain below 30%.
X: A ring of traces remains 70% or more.

<Marker resistance>
The ink-jet ink composition prepared at a concentration of 15% by mass is filled in an ink cartridge, printed on plain paper with an ink-jet printer EM-930C (manufactured by Seiko Epson Corporation), and then the KOKUYO line marker on the plain-paper printing part. A line was drawn with a pen (PM-LM103Y), and the marker resistance was evaluated according to the following criteria. The results are shown in Table 3 and Table 4.
○: The printed part is not soiled.
Δ: Slight dirt and blurring are observed around the printed portion and characters.
X: The printed portion is blurred and the portions other than the printed portion are stained.

From the results of Table 3 and Table 4, the pigment dispersion compositions obtained in Examples 1 to 6 were
By including the polyurethane resin-added pigment (A) and the aqueous dispersion resin (B) having an average particle diameter of 10 to 300 nm, it exhibits excellent image density, dispersibility and storage stability, and is re-dissolvable. It can also be seen that it has excellent marker resistance.

  According to the present invention, it is possible to provide a pigment dispersion composition and an ink-jet ink composition that exhibit excellent image density, dispersibility, and storage stability, and are excellent in re-solubility, marker resistance, and scratch resistance. it can.

Claims (5)

A pigment (I) having an acidic group on the surface and a basic compound (II) having two or more amino groups in the molecule selected from a primary amino group and a secondary amino group are brought into contact with each other in an aqueous medium. After preparing a pigment having an unreacted amino group, an aqueous dispersion of a polyurethane resin-added pigment (A) formed by contacting with a polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups and urea bonding;
A pigment dispersion composition comprising an aqueous dispersion resin (B) having an average particle diameter of 10 to 300 nm.   The pigment dispersion composition according to claim 1, wherein the polyisocyanate polyurethane resin (III) having two or more terminal isocyanate groups has a solid content acid value of 20 to 200 mgKOH / g.   The aqueous dispersion resin (B) is a self-dispersing aqueous dispersion resin having an anion group or a nonion group in the molecule, or an emulsifier dispersion type aqueous dispersion resin dispersed by an anionic emulsifier and / or a nonionic emulsifier. The pigment dispersion composition according to claim 1 or 2.   The pigment dispersion composition according to any one of claims 1 to 3, wherein the pigment (I) having an acidic group on the surface is self-dispersing carbon black having an acidic group on the surface.   An inkjet ink composition comprising the pigment dispersion composition according to any one of claims 1 to 4.