JP2006016455A - Ink composition for ink-jet recording and image-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition for ink-jet recording having excellent ink ejecting property, usable independent of the recording object, enabling photosetting over a wide wavelength range (especially curing with visible light) and giving a recorded image having especially excellent light resistance, ozone resistance and scratch resistance. <P>SOLUTION: The ink composition contains an ethylenic unsaturated monomer, a dye having an oxidation potential nobler than 1.0V (vs SCE) and an organic boron compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink composition for ink jet recording and an image forming method using the same, and more particularly to an ink composition for ink jet recording capable of forming a robust image and an image forming method using the ink composition.

  As an ink having fading resistance, a UV ink that is cured by irradiation with ultraviolet rays (UV) and has a UV light shielding property is known (for example, see Patent Document 1). Since this UV ink is generally configured to correspond to a light source capable of high-illuminance exposure in the UV wavelength region, only a light source that emits UV light can be used, and such a light source is expensive and is generated during UV exposure. There is a problem that needs to be treated to discharge ozone and heat.

  On the other hand, in recent years, ink jet printers that use ink jet recording methods that perform recording by ejecting ink are widely used for printing on paper, film, cloth, etc. not only in offices but also in general households. It's being used. Oil-based inks, water-based inks, and solid inks are known as inks for ink-jet recording. Among these, water-based inks are advantageous in terms of manufacturability, handleability, odor, safety, and the like. Yes, water-based ink has become mainstream.

However, many of the water-based inks use a water-soluble dye that dissolves in a molecular state, and thus have an advantage of high transparency and color density. However, since the dye is water-soluble, the water resistance is poor, so-called When printing on plain paper, bleeding (bleeding) occurs, the printing quality is remarkably deteriorated, the light resistance is inferior, and the recording paper is provided with an ink-receptive recording layer having porous inorganic fine particles on the surface. (Hereinafter, sometimes referred to as “photographic quality paper”) has a problem that the image storage stability is significantly deteriorated due to the influence of oxidizing gas (SO _x , NO _x , ozone, etc.). It was.

  Therefore, water-based inks using pigments and disperse dyes have been proposed for the purpose of solving the above-described problems (see, for example, Patent Document 2). However, in the case of this water-based ink, although the water resistance is improved to some extent, it is difficult to say that it is sufficient, and the storage stability of the pigment or disperse dye dispersion in the water-based ink is lacking, which causes clogging at the ink discharge port. There are problems such as easy. Further, when photographic image quality paper is used, there is a problem that inks using pigments and dyes have poor permeability and the pigments and dyes are easily peeled off from the surface when rubbed by hand, that is, they are poor in scratch resistance.

  On the other hand, a method of encapsulating an oil-soluble dye in a polymer has been proposed (see, for example, Patent Documents 3 to 4). However, the ink for ink jet recording obtained by this method has insufficient color tone, insufficient color reproducibility, and in particular, insufficient image durability when exposed to an oxidizing gas, etc. Is not sufficiently scratch resistant when printed on photographic quality paper. There is also a proposal regarding a method of preventing the fluorescent dye from being oxidized by oxygen in the air by covering the fluorescent dye with a resin having low oxygen permeability (see, for example, Patent Document 5). This is simply a resin and a fluorescent dye added to a certain solvent so as to cover the color tone and color reproducibility in the same manner as described above, and this method is used to suppress discoloration of colored compounds containing dyes or pigments. There is no example to apply to the application.

Further, in order to improve the colorability, hue or scratch resistance of the ink, a polymer in which a salt-forming group and a polyalkylene oxide group are introduced (for example, see Patent Document 6), a high-boiling organic solvent and a dye are used. (For example, see Patent Document 7), the former has good scratch resistance with fingers, but cannot satisfy the high level of scratch resistance due to eraser rubbing or the like, and the latter has a high level of image resistance. It was insufficient in applications requiring durability.
JP 2003-221528 A JP-A-56-157468 JP 58-45272 A JP 62-241901 A JP 2002-179968 A Japanese Patent Laid-Open No. 2001-123097 JP 2001-262018 A

  As described above, there is no known technology other than an image recording technology that uses ultraviolet curable to show fading resistance to ultraviolet light, and an inexpensive device or image formation using any wavelength light is selected. In addition, it has excellent ejection stability without clogging at the tip of the ejection nozzle, has good ink permeability without depending on the recording material, and has a desired wavelength for the ink composition after recording. The technology that realizes high-density and high-quality recording that is particularly excellent in light resistance, ozone resistance, and scratch resistance by exposing and curing using light has not yet been established. It is.

  The present invention has been made in view of the above, and is excellent in ink discharge property when discharged using a discharge nozzle and is not dependent on a recording material, and is photocured in a wide wavelength region (particularly, cured by visible light). Ink-jet recording ink composition capable of recording an image particularly excellent in light resistance, ozone resistance, and scratch resistance (hereinafter collectively referred to as “image fastness”), and An object of the present invention is to provide an image forming method that uses the ink composition for ink jet recording and can easily record an image particularly excellent in image fastness, and to achieve the object.

Specific means for solving the above problems are as follows.
<1> An ink composition for ink-jet recording comprising at least an ethylenically unsaturated monomer, a dye having an oxidation potential nobler than 1.0 V (vs SCE), and an organic boron compound.
<2> The ethylenically unsaturated monomer has an oxygen permeability coefficient at 25 ° C. of 2.6 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less due to a polymerization reaction. The ink composition for ink jet recording according to <1>, which is a compound constituting a polymer.
<3> The ink composition for ink jet recording according to <1> or <2>, wherein a solution containing at least the ethylenically unsaturated monomer, the dye, and the organoboron compound is emulsified and dispersed in an aqueous medium. is there.
<4> A step of recording an image on a recording material using the ink composition for ink jet recording according to any one of <1> to <3>, and curing the recorded image by irradiating light An image forming method characterized by including an image forming step.

  According to the present invention, the ink ejection property when ejecting using the ejection nozzle is excellent, and there is no dependency on the recording material, and photocuring in a wide wavelength region (particularly curing with visible light) is possible, and light fastness is achieved. Ink jet recording ink composition capable of recording an image particularly excellent in ozone resistance and scratch resistance (image fastness), and the ink fastness of the ink jet recording are used, and the image fastness is particularly excellent. Therefore, it is possible to provide an image forming method capable of easily recording a recorded image.

The present invention enables polymerization curing by irradiation with light of a desired wavelength (especially visible light) after ink jet recording, that is, improvement of image fastness. This improvement in image fastness has an oxygen transmission coefficient particularly at 25 ° C. 2.6 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less, which is effective when configured with an ethylenically unsaturated monomer It is. Hereinafter, the ink composition for inkjet recording of the present invention and an image forming method using the same will be described in detail.

<Ink composition for inkjet recording>
The ink composition for ink jet recording of the present invention contains at least an ethylenically unsaturated monomer, a dye having an oxidation potential nobler than 1.0 V (vs SCE), and an organic boron compound, and is polymerized and cured when exposed to light. In addition to the above components, it can be configured using other components such as various additives as necessary.

[Ethylenically unsaturated monomer]
The ink composition for inkjet recording of the present invention contains at least one ethylenically unsaturated monomer. An ethylenically unsaturated monomer can be added and polymerized upon irradiation with light by the action of an organoboron compound to be described later to cure itself, and the composition constituting the image can be cured to improve fastness to light, ozone, abrasion, etc. Is.

  The ethylenically unsaturated monomer (hereinafter also simply referred to as “monomer”) is a compound having at least one ethylenic double bond (hereinafter also referred to as “polymerizable group”) as a polymerizable group, A monofunctional monomer having a single polymerizable group and a bifunctional or higher compound having two or more polymerizable groups (polyfunctional monomer) can be appropriately selected and used. For example, it is also possible to configure a mode in which a monofunctional monomer is used in combination with a bifunctional monomer for viscosity adjustment, crosslink density adjustment, and physical property control after curing (strength, adhesiveness, etc.).

  Examples of the polymerizable group include an acryloyl group, a methacryloyl group, an allyl group, a vinyl group, an internal double bond group (such as maleic acid), and the like. Preferably, an acryloyl group is particularly preferable.

  Examples of the polyfunctional monomer include vinyl group-containing aromatic compounds, acrylates which are esters of two or more alcohols and acrylic acid or methacrylic acid, acrylamides which are amides of two or more amines and acrylic acid or methacrylic acid, Polyester acrylate in which acrylic acid or methacrylic acid is introduced into an ester or polycaprolactone obtained by combining a polybasic acid and a dihydric alcohol, or acrylic acid or methacrylic acid is introduced into an ether obtained by combining an alkylene oxide and a polyhydric alcohol Polyether acrylate, epoxy acrylate obtained by introducing acrylic acid or methacrylic acid into epoxy resin, or by reacting a dihydric or higher alcohol with an epoxy-containing monomer, urethane acrylate having urethane bond, amino resin Examples include acrylates, acrylic resin acrylates, alkyd resin acrylates, spirane resin acrylates, silicone resin acrylates, reaction products of unsaturated polyesters with photopolymerizable monomers (eg, acrylic acid, methacrylic acid, etc.), acrylates, polyester acrylates, etc. , Polyether acrylate, epoxy acrylate, urethane acrylate, acrylic resin acrylate, silicone resin acrylate, reaction product of unsaturated polyester and photopolymerizable monomer is preferable, acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane acrylate Particularly preferred.

  Specific examples of the polyfunctional monomer include divinylbenzene, 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, 1 , 6-acryloylaminohexane, hydroxypivalate ester neopentyl glycol diacrylate, a (meth) acryloyl group (methacryloyl group and acryloyl group) at the molecular chain end of a polyester having a molecular weight of 500 to 30,000 consisting of a dibasic acid and a dihydric alcohol. Epoxy having a molecular weight of 450 to 30,000 including a polyester (meth) acrylate having a general group), polyethylene glycol diacrylate, and a bisphenol (A or S, F) skeleton A acrylate, a phenol novolak resin-containing epoxy acrylate having a molecular weight of 600 to 30,000, a reaction product of a polyvalent isocyanate having a molecular weight of 350 to 30,000 and a (meth) acrylic acid monomer having a hydroxyl group, and a urethane bond in the molecule Examples thereof include modified urethane.

  Examples of the monofunctional monomer include substituted or unsubstituted (meth) acrylate, substituted or unsubstituted styrene, substituted or unsubstituted acrylamide, vinyl group-containing monomers (vinyl esters, vinyl ethers, N-vinylamide, etc.), (Meth) acrylic acid, etc., and substituted or unsubstituted (meth) acrylate, substituted or unsubstituted acrylamide, vinyl esters and vinyl ethers are preferred, substituted or unsubstituted (meth) acrylate, substituted or unsubstituted Acrylamide is particularly preferred. Examples of the substituent of the monofunctional monomer include a hydroxy group, a glycidyl group, an alkyl group, an alkoxy group, an aryl group, a halogen, and a polymer residue.

  Specific examples of the monofunctional monomer include hydroxyethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, 2-acryloyloxyethyl phosphate, allyl acrylate, N, N-dimethylaminoethyl acrylate, N, N -Dimethylacrylamide, N, N-diethylaminopropylacrylamide, N-butoxymethylacrylamide, acryloylmorpholine, 2-hydroxyethyl vinyl ether, N-vinylformamide, N-vinylacetamide, 2-cyclohexylcarbamoyloxyethyl acrylate, polybutyl acrylate to ester Acrylate having a moiety, acrylate having a polydimethylsiloxane moiety in the ester, etc. That.

  The content of the ethylenically unsaturated monomer in the ink composition for ink jet recording is usually preferably in the range of 50 to 99.6% by mass.

  In addition, the monomer can be appropriately selected from the above as long as the effects of the present invention can be obtained, but it is more preferable to select a monomer having high safety. Highly safe monomers are those having a small PII (skin irritation) value, and those having a PII of 3.0 or less are preferred, more preferably 2.0 or less, and even more preferably 1.0 or less. Particularly preferably, it is 0.5 or less.

Among the above, the oxygen transmission coefficient at 25 ° C. by the polymerization reaction is 2.6 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less (preferably 2.3 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less) Preferred compounds are desirable.

The oxygen transmission coefficient can be measured at 25 ° C. using a known oxygen electrode method. The method for measuring the oxygen permeation coefficient of organic compounds is described in the book, and is described in detail, for example, in “Polymers and Water” (edited by the Society of Polymer Science, p. 283 to 323, published by Koshobo, Showa 47). Yes. The value of the oxygen permeation coefficient defined in the present invention is calculated using an oxygen electrode method capable of measuring even a fluid oily substance. The oxygen permeability coefficient [unit: m ³ (STP) · m / (s · m ² · kPa)] was measured using an oxygen analyzer (model 3600 [diaphragm 2956A 25 μm], manufactured by Orbis Fair Laboratories Japan Inc.). The oily substance to be measured can be fixed on the detection head in the form of a uniform film under the conditions of 25 ° C. and humidity of 50 RH%, and the oxygen concentration detected by the electrode is calibrated using a standard transmission sample.

From the viewpoint of reducing the oxygen permeability coefficient of a polymer obtained by polymerization of an ethylenically unsaturated monomer, the monomer has a structural site capable of taking a hydrogen bond, particularly from an amide bond, a urethane bond, a glycidyl group, and a hydroxyl group. It is preferable to have one or two or more selected.
Specifically, a monomer having one kind or two or more kinds selected from groups represented by the following general formulas (i) to (iii) is preferable.

In the formulas (i) to (iii), each R ¹ independently represents a linear or branched alkylene group or alkyleneoxy group which may have a substituent, and R ² represents a hydrogen atom, a halogen atom, or a halogen atom. An atom, an alkyl group, an alkoxy group, or a cyano group is represented.

  Suitable ethylenically unsaturated monomers for reducing the oxygen permeability coefficient of the polymer after polymerization include, for example, N-monosubstituted acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, N-disubstituted methacrylamide Glycidyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl acrylate glycidyl ether, 2-chloroethyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, 2,3 -Dihydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxypropyl acrylate, etc. may be mentioned, and one or more of these may be selected and used suitably. Kill.

  Hereinafter, specific examples (exemplary polymers PA-1 to PA-11) of polymers synthesized from ethylenically unsaturated monomers are listed. The ratio in parentheses means mass ratio, and the present invention is not limited to these specific examples.

PA-1) n-butyl acrylate / 2-hydroxyethyl acrylate copolymer (= 70/30; Mw = 24300, oxygen permeability coefficient: 1.05 × 10 ⁻¹³ [m ³ (STP) · m / (s・ M ²・ kPa)])
PA-2) n-butyl acrylate / 4-hydroxybutyl acrylate copolymer (= 70/30; Mw = 2200, oxygen transmission coefficient: 1.26 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)))
PA-3) n-butyl acrylate / 2-chloroethyl acrylate copolymer (= 70/30; Mw = 30600, oxygen permeability coefficient: 1.20 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)))
PA-4) n-butyl acrylate / glycidyl methacrylate copolymer (= 70/30; Mw = 33000, oxygen permeability coefficient: 1.25 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)])
PA-5) copolymer of n-butyl acrylate / 4-hydroxyethyl acrylate glycidyl ether (= 70/30; Mw = 18200, oxygen permeability coefficient: 1.72 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)])
PA-6) n-butyl acrylate / phenoxyethyl acrylate copolymer (= 70/30; MW = 18500, oxygen permeability coefficient: 1.47 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ²・ kPa)))
PA-7) n-butyl acrylate / t-butyl acrylamide copolymer (= 90/10; Mw = 30600, oxygen permeability coefficient: 2.11 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)))
PA-8) n-butyl acrylate / N-isopropylacrylamide copolymer (= 90/10; Mw = 30300, oxygen permeability coefficient: 2.15 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)))
PA-9) Copolymer of methyl acrylate / M-90G (manufactured by Shin-Nakamura Chemical Co., Ltd.) (= 70/30; Mw = 25800, oxygen permeability coefficient: 2.48 × 10 ⁻¹³ [m ³ (STP)・ M / (s ・ m ²・ kPa)])
PA-10) n-butyl acrylate / N-isopropylyacrylamide copolymer (= 70/30; Mw = 30600, oxygen permeability coefficient: 0.09 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)))
PA-11) Copolymer of n-butyl acrylate / t-butyl acrylamide (= 50/50; MW = 25900, oxygen permeability coefficient: 0.16 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)))

The oxygen permeability coefficient of the polymer synthesized from the ethylenically unsaturated monomer will be described in more detail by taking the exemplified polymer PA-1 as an example.
First, a polymer solution PA-1 is synthesized as follows (Synthesis Example 1). That is,
To a 200 ml three-diameter flask substituted with nitrogen gas, 22 parts of methyl ethyl ketone and 8.3 parts of 2-propanol were added and heated to 65 ° C., and then 0.17 part of azobisvaleronitrile (V-65) was added. Added further. Next, a mixed solution of 35 parts of n-butyl acrylate, 15 parts of 2-hydroxyethyl acrylate, 0.42 parts of n-dodecanethiol, 22 parts of methyl ethyl ketone, and 8.3 parts of 2-propanol was added to this for 2 hours. It was dripped over. Subsequently, after 2 hours of reaction, 0.088 parts of V-65 was added afterwards and the temperature was raised to 73 ° C. Further, after the reaction for 2 hours, a target polymer solution PA-1 having a solid content concentration of 45% was synthesized. Thereafter, PA-1 was fixed in a uniform film shape on the detection head under the conditions of 25 ° C. and humidity 50 RH% with an oxygen analyzer (model 3600 [diaphragm 2956A 25 μm], manufactured by Orbis Fair Laboratories Japan Inc.) The oxygen transmission coefficient can be calculated by calibrating the detected oxygen concentration using a standard transmission sample.

In the ink composition for ink jet recording of the present invention, the monomer content is not particularly limited, but from the viewpoint of maintaining good solubility of the dye according to the present invention (particularly oil-soluble dye) described later, the monomer content The amount is preferably 30% by mass or more and 2000% by mass or less, and more preferably 100% by mass or more and 1500% by mass or less with respect to the dye according to the present invention. If the monomer content is too high, there is a tendency that stable and fine dispersion becomes difficult due to the excessive proportion of the oil phase. From this viewpoint, the monomer content is particularly the dye according to the present invention (especially 50-1500 mass% is preferable with respect to an oil-soluble dye), and 100-1000 mass% is more preferable.
Further, from the viewpoint of good ink penetration into the recording material, the monomer content in the colored fine particles is 25% by mass or more and 90% by mass or less in the case of, for example, an emulsion dispersion method as described later. Preferably, it is 50 mass% or more and 85 mass% or less.

[dye]
The ink composition for ink jet recording of the present invention contains at least one kind of dye having an oxidation potential nobler than 1.0 V (vs SCE) (the dye according to the present invention; hereinafter, also simply referred to as a dye). By selecting a material having a high oxidation potential and nobler than 1.0 V (vs. SCE), it is possible to effectively improve the discoloration of the image, in particular, resistance to oxidizing substances such as ozone, curing properties, and image abrasion resistance. be able to.

  With respect to the method for measuring the oxidation potential (Eox), for example, “New Instrumental Methods in Electrochemistry” by P. Delahay (1954, published by Interscience Publishers) J. et al. “Electrochemical Methods” by Bard et al. (1980, published by John Wiley & Sons) and “Electrochemical Measurement Methods” by Akira Fujishima et al. (1984, published by Gihodo Publishing Co., Ltd.).

Specifically, the oxidation potential is 1 × 10 ⁻⁴ to 1 × 10 ⁻⁶ mol / liter in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate. When the test sample was dissolved, carbon (GC) was used as the working electrode, a rotating platinum electrode was used as the counter electrode, and the oxidation when swept to the oxidation side (noble side) by cyclic voltammetry or DC polarography equipment Approximate the wave with a straight line, and the line formed by the intersection of this straight line and the residual current / potential line and the intersection of the straight line and the saturation current line (or the intersection of the straight line parallel to the vertical axis passing through the peak potential value) The intermediate potential value in minutes is measured as the value for SCE (saturated calomel electrode). Although this value may be deviated by several tens of mV due to the influence of the liquid potential difference or the liquid resistance of the sample solution, the reproducibility of the potential can be ensured by inserting a standard sample (for example, hydroquinone). The supporting electrolyte and solvent to be used can be selected appropriately depending on the oxidation potential and solubility of the test sample. Usable supporting electrolytes and solvents are described in Akira Fujishima et al., “Electrochemical measurement method” (p. 101-118 (1984), published by Gihodo Publishing Co., Ltd.). In the concentration range of the measurement solvent and the phthalocyanine compound sample, the oxidation potential in a non-association state is measured.

The value of Eox represents the ease of electron transfer from the sample to the electrode. The higher the value (the oxidation potential is noble), the more difficult the electron transfer from the sample to the electrode, in other words, the less easily oxidized. Represents. In relation to the structure of the compound, the oxidation potential can be made more noble by introducing an electron withdrawing group, and the oxidation potential can be made lower by introducing an electron donating group. In the present invention, from the viewpoint of lowering the reactivity with ozone which is an electrophile, it is desirable that an electron withdrawing group is introduced and the oxidation potential is more noble. Thus, by using the Hammett's substituent constant sigma _p value is an electron-withdrawing or electron-donating measure substituent, a sulfinyl group, a sulfonyl group, a sulfamoyl group, as sulfonylsulfamoyl group, sigma _p value It can be said that the oxidation potential can be made more noble by introducing a large substituent.

As for the Hammett substituent constant σ _p value, Hammett's rule is an empirical rule proposed by LP Hammett in 1935 to quantitatively discuss the influence of substituents on the reaction or equilibrium of benzene derivatives. Substituent constants determined based on this Hammett's rule include a σ _p value and a σ _m value, and these values are widely accepted today. The σ _p and σ _m values are detailed in many common books. For example, JADean, “Lange's Handbook of Chemistry” (12th edition (1979), Mc Graw-Hill) (Extra edition, No. 122, pages 96-103 (1979), Nankodo). Note that the σ _p value is not limited to a substituent having a value known in the literature as in the above-mentioned book, but is included in the range when the literature is unknown and measured based on the Hammett rule. It also includes substituents that would be

  In the present invention, it is particularly preferable to use a dye having an oxidation potential higher than 1.1 V (vs SCE), and it is particularly preferable to use a dye higher than 1.15 V (vs SCE).

As the dye according to the present invention, a water-insoluble dye can be preferably used among the dyes satisfying the oxidation potential range. Here, the water-insoluble dye has affinity with the polymer formed by polymerization from the above-mentioned monomers, and does not elute into the aqueous medium when colored fine particles containing the dye and the monomer are dispersed in the aqueous medium. Means a pigment. More specifically, it means that the solubility in water at 25 ° C. (mass of dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. .
From the above, so-called oil-soluble dyes that are insoluble in water are preferably used.

  The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By using an oil-soluble dye having a low melting point, pigment crystal precipitation in the ink composition is suppressed, and the storage stability of the ink composition is improved.

  The oil-soluble dye can be appropriately selected from conventionally known compounds (dyes). Specifically, the dyes described in paragraphs [0023] to [0053] of JP-A No. 2002-114930 are used. Etc. In the ink composition for ink jet recording of the present invention, the oil-soluble dye may be used alone or in combination of several kinds. Further, if necessary, colorants such as other water-soluble dyes, disperse dyes, and pigments may be contained.

Next, the oil-soluble dye will be described in detail for each color.
As the yellow oil-soluble dye, an oil-soluble dye represented by the following general formula (Y-I) is preferable. The oil-soluble dye represented by the general formula (Y-I) may be used not only for yellow but also for other colors such as black ink, green ink, and red ink.

A-N = NB ... General formula (Y-I)
In the general formula (Y-I), A and B each independently represent a heterocyclic group which may have a substituent. The heterocyclic ring is preferably a 5- or 6-membered heterocyclic ring, which may be a monocyclic structure or a polycyclic structure in which two or more rings are condensed, and is an aromatic heterocyclic ring. May also be a non-aromatic heterocyclic ring. As a hetero atom constituting the heterocyclic ring, a nitrogen atom, an oxygen atom and a sulfur atom are preferable.

  Examples of the heterocyclic ring represented by A include 5-pyrazolone, pyrazole, oxazolone, isoxazolone, barbituric acid, pyridone, rhodanine, pyrazolidinedione, pyrazolopyridone, pyrazoloazoles, or a ring derived from meldrum acid, In addition, a condensed heterocyclic ring in which a hydrocarbon aromatic ring or a heterocyclic ring is further condensed to these rings is preferable. Among these, 5-pyrazolone, 5-aminopyrazole, pyridone, and pyrazoloazoles are preferable, and 5-aminopyrazole, 2-hydroxy-6-pyridone, and pyrazolotriazole are particularly preferable.

  Examples of the heterocyclic ring represented by B include pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, pyrazole, imidazole, Preferred examples include benzimidazole, triazole, oxazole, isoxazole, benzoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, benzisoxazole, pyrrolidine, piperidine, piperazine, imidazolidine and thiazoline. Among them, pyridine, quinoline, thiophene, benzothiophene, pyrazole, imidazole, benzimidazole, triazole, oxazole, isoxazole, benzoxazole, benzisoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, benzisoxazole Quinoline, thiophene, pyrazole, thiazole, benzoxazole, benzisoxazole, isothiazole, imidazole, benzothiazole, thiadiazole are more preferable, and pyrazole, benzothiazole, benzoxazole, imidazole, 1,2,4-thiadiazole, 1 3,4-thiadiazole is particularly preferred.

  Examples of the substituent that can be substituted for A and B include a halogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxyl group, a nitro group, and an alkoxy group. , Aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino Group, sulfamoylamino group, alkyl and arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, alkyl and arylsulfinyl group, alkyl and aryl Ruhoniru group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an imido group, a phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, a silyl group.

  Among the dyes represented by the general formula (Y-I), dyes represented by the following general formula (Y-II), (Y-III), or (Y-IV) are more preferable.

In the general formula (Y-II), R ¹ and R ³ are each independently a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an arylthio group, an aryl group, or Represents an ionic hydrophilic group. R ² represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, a carbamoyl group, an acyl group, an aryl group, or a heterocyclic group, and R ⁴ represents a heterocyclic group.

In the general formula (Y-III), R ⁵ represents a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an arylthio group, an aryl group, or an ionic hydrophilic group. , R ⁶ represents a heterocyclic group. Za is -N =, - NH-, or C (R ¹¹⁾ = represents, Zb and Zc each independently -N = or C (R ¹¹⁾ = represents, R ¹¹ is a hydrogen atom or a nonmetallic Represents a substituent.

In the general formula (Y-IV), R ⁷ and R ⁹ are each independently a hydrogen atom, cyano group, alkyl group, cycloalkyl group, aralkyl group, aryl group, alkylthio group, arylthio group, alkoxycarbonyl group, A carbamoyl group or an ionic hydrophilic group is represented. R ⁸ is a hydrogen atom, halogen atom, alkyl group, alkoxy group, aryl group, aryloxy group, cyano group, acylamino group, sulfonylamino group, alkoxycarbonylamino group, ureido group, alkylthio group, arylthio group, alkoxycarbonyl group Carbamoyl group, sulfamoyl group, sulfonyl group, acyl group, amino group, substituted amino group, hydroxy group, or ionic hydrophilic group. R ¹⁰ represents a heterocyclic group.

The groups represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ⁹ in the general formulas (Y-II), (Y-III), and (Y-IV) are as follows. It will be described in detail.

The alkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ , or R ⁹ includes an alkyl group having a substituent and an unsubstituted alkyl group. As the alkyl group, an alkyl group having 1 to 20 carbon atoms is preferable, and examples of the substituent include a hydroxyl group, an alkoxy group, a cyano group, a halogen atom, and an ionic hydrophilic group. Specific examples of the (substituted) alkyl group include methyl group, ethyl group, butyl group, isopropyl group, t-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, trifluoromethyl group, 3-sulfopropyl group. Group and 4-sulfobutyl group are preferable.

The cycloalkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , or R ⁹ includes a cycloalkyl group having a substituent and an unsubstituted cycloalkyl group. As the cycloalkyl group, a cycloalkyl group having 5 to 12 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group. A specific example of the (substituted) cycloalkyl group is preferably a cyclohexyl group.

The aralkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ or R ⁹ includes an aralkyl group having a substituent and an unsubstituted aralkyl group. The aralkyl group is preferably an aralkyl group having 7 to 20 carbon atoms, and examples of the substituent include an ionic hydrophilic group. Specific examples of the (substituted) aralkyl group include a benzyl group and a 2-phenethyl group.

The aryl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ , or R ⁹ includes an aryl group having a substituent and an unsubstituted aryl group. As the aryl group, an aryl group having 6 to 20 carbon atoms is preferable, and examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, an alkylamino group, and an ionic hydrophilic group. Specific examples of the (substituted) aryl group include a phenyl group, a p-tolyl group, a p-methoxyphenyl group, an o-chlorophenyl group, and an m- (3-sulfopropylamino) phenyl group.

The alkylthio group represented by R ¹ , R ³ , R ⁵ , R ⁷ , R ⁸ , or R ⁹ includes an alkylthio group having a substituent and an unsubstituted alkylthio group. The alkylthio group is preferably an alkylthio group having 1 to 20 carbon atoms, and examples of the substituent include an ionic hydrophilic group. Specific examples of the (substituted) alkylthio group include a methylthio group and an ethylthio group.

The arylthio group represented by R ¹ , R ³ , R ⁵ , R ⁷ , R ⁸ , or R ⁹ includes an arylthio group having a substituent and an unsubstituted arylthio group. As the arylthio group, an arylthio group having 6 to 20 carbon atoms is preferable, and examples of the substituent include an alkyl group and an ionic hydrophilic group. Specific examples of the (substituted) arylthio group include a phenylthio group and a p-tolylthio group.

The heterocyclic group represented by R ² is preferably a 5-membered or 6-membered heterocyclic ring, and may be further condensed. As a hetero atom constituting the heterocyclic ring, a nitrogen atom, a sulfur atom and an oxygen atom are preferable. Moreover, it may be an aromatic heterocyclic ring or a non-aromatic heterocyclic ring, and the heterocyclic ring may further have a substituent. Preferred examples of the substituent here include the same substituents as those described above for the aryl group. Preferred heterocycles include 6-membered nitrogen-containing aromatic heterocycles, and triazine, pyrimidine and phthalazine are particularly preferred.

Preferred examples of the halogen atom represented by R ⁸ include a fluorine atom, a chlorine atom, and a bromine atom.

The alkoxy group represented by R ¹ , R ³ , R ⁵ and R ⁸ includes an alkoxy group having a substituent and an unsubstituted alkoxy group. As the alkoxy group, an alkoxy group having 1 to 20 carbon atoms is preferable, and examples of the substituent include a hydroxyl group and an ionic hydrophilic group. Specific examples of the (substituted) alkoxy group include a methoxy group, an ethoxy group, an isopropoxy group, a methoxyethoxy group, a hydroxyethoxy group, or a 3-carboxypropoxy group.

The aryloxy group represented by R ⁸ includes an aryloxy group having a substituent and an unsubstituted aryloxy group. As the aryloxy group, an aryloxy group having 6 to 20 carbon atoms is preferable, and examples of the substituent include an alkoxy group and an ionic hydrophilic group. Preferable examples of the (substituted) aryloxy group include a phenoxy group, a p-methoxyphenoxy group, and an o-methoxyphenoxy group.

The acylamino group represented by R ⁸ includes an acylamino group having a substituent and an unsubstituted acylamino group. As the acylamino group, an acylamino group having 2 to 20 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group. Specific examples of the (substituted) acylamino group include an acetamido group, a propionamido group, a benzamido group, or a 3,5-disulfobenzamido group.

The sulfonylamino group represented by R ⁸ includes a sulfonylamino group having a substituent and an unsubstituted sulfonylamino group. The sulfonylamino group is preferably a sulfonylamino group having 1 to 20 carbon atoms. Examples of the substituent include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and an iso- group. A butyl group and a tert-butyl group are included. Specific examples include, in addition to the sulfonylamino group, for example, a methylsulfonylamino group and an ethylsulfonylamino group.

The alkoxycarbonylamino group represented by R ⁸ includes an alkoxycarbonylamino group having a substituent and an unsubstituted alkoxycarbonylamino group. As the alkoxycarbonylamino group, an alkoxycarbonylamino group having 2 to 20 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group. A specific example of the (substituted) alkoxycarbonylamino group is preferably an ethoxycarbonylamino group.

The ureido group represented by R ⁸ includes a ureido group having a substituent and an unsubstituted ureido group. The ureido group is preferably a ureido group having 1 to 20 carbon atoms, and examples of the substituent include an alkyl group and an aryl group. Specific examples of the (substituted) ureido group include a 3-methylureido group, a 3,3-dimethylureido group, and a 3-phenylureido group.

The alkoxycarbonyl group represented by R ⁷ , R ⁸ , or R ⁹ includes an alkoxycarbonyl group having a substituent and an unsubstituted alkoxycarbonyl group. As the alkoxycarbonyl group, an alkoxycarbonyl group having 2 to 20 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group. Specific examples of the (substituted) alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

The carbamoyl group represented by R ² , R ⁷ , R ⁸ , or R ⁹ includes a carbamoyl group having a substituent and an unsubstituted carbamoyl group, and examples of the substituent include an alkyl group. Specific examples of the (substituted) carbamoyl group include a methylcarbamoyl group and a dimethylcarbamoyl group.

The sulfamoyl group represented by R ⁸ includes a sulfamoyl group having a substituent and an unsubstituted sulfamoyl group, and examples of the substituent include an alkyl group. Specific examples of the (substituted) sulfamoyl group include a dimethylsulfamoyl group and a di- (2-hydroxyethyl) sulfamoyl group.
Examples of the sulfonyl group represented by R ⁸ include methanesulfonyl and phenylsulfonyl.

The acyl group represented by R ² and R ⁸ includes an acyl group having a substituent and an unsubstituted acyl group. The acyl group is preferably an acyl group having 1 to 20 carbon atoms, and examples of the substituent include an ionic hydrophilic group. Specific examples of the (substituted) acyl group include an acetyl group and a benzoyl group.

The ionic hydrophilic group represented by R ¹ , R ³ , R ⁵ , R ⁷ , R ⁸ , or R ⁹ includes a carboxyl group, a quaternary ammonium salt, a sulfonic acid group, and the like. Preferred examples include a carboxyl group and a sulfonic acid group.

The aralkyl group represented by R ² includes an aralkyl group having a substituent and an unsubstituted aralkyl group. Examples of the substituent include a hydroxy group, an alkoxy group, a cyano group, a halogen atom, and an ionic hydrophilic group. Sex groups are included. Examples of the aryl moiety of the aralkyl group include a phenyl group and a naphthyl group, and specific examples include a benzyl group and a 2-phenethyl group.

In the substituted amino group represented by R ⁸ , examples of the substituent include an alkyl group, an aryl group, and a heterocyclic group. Specific examples of the substituted amino group include a methylamino group, a diethylamino group, and an anilino group. A group or 2-chloroanilino group is preferably exemplified.

The details of each of the substituents enumerated in each group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ or R ⁹ are the same as described above, and the preferred embodiments are also the same. It is.

In the general formulas (Y-II), (Y-III), and (Y-IV), the heterocyclic group represented by R ⁴ , R ⁶ , or R ¹⁰ is represented by the general formula (Y-I). It is synonymous with the optionally substituted heterocyclic group represented by B, and preferred examples, more preferred examples, and particularly preferred examples are also the same as above. Examples of the substituent include an ionic hydrophilic group, an alkyl group having 1 to 12 carbon atoms, an aryl group, an alkyl or arylthio group, a halogen atom, a cyano group, a sulfamoyl group, a sulfonamino group, a carbamoyl group, and An acylamino group etc. are mentioned, These groups, such as an alkyl group and an aryl group, may have a substituent further.

  In addition, as an example of the substituent in the case where it may further have a substituent, the substituent which may be substituted on the heterocyclic rings A and B in the general formula (Y-I) can be exemplified.

In the general formula (Y-III), Za is -N =, - NH-, or -C (R ¹¹⁾ = represents, Zb and Zc each independently -N = or -C (R ¹¹⁾ = a To express. Here, R ¹¹ represents a hydrogen atom or a nonmetal substituent, and examples of the nonmetal substituent represented by R ¹¹ include a cyano group, a cycloalkyl group, an aralkyl group, an aryl group, an alkylthio group, an arylthio group, or an ion. A hydrophilic group is preferred. Each of these groups has the same meaning as each group in R ¹ , and preferred examples are also the same.

Examples of the skeleton of a heterocyclic ring composed of two 5-membered rings contained in the general formula (Y-III) are shown below.

  Specific examples of the dye represented by the general formula (Y-I) include exemplified compounds Y-101 to Y-155 described in paragraph numbers [0139] to [0149] of JP-A-2003-073598. However, the present invention is not limited to these specific examples. These compounds can be synthesized with reference to JP-A-2-24191 and JP-A-2001-279145.

  The magenta oil-soluble dye is preferably a compound having a structure represented by the general formulas (3) and (4) of JP-A No. 2002-114930, and specific examples include paragraphs of JP-A No. 2002-114930. And compounds described in the numbers [0054] to [0073]. Particularly preferred dyes are azo dyes represented by general formulas (M-1) to (M-2) described in paragraph numbers [0084] to [0122] of JP-A No. 2002-121414, and specific examples thereof. Examples thereof include compounds described in JP-A-2002-121414, paragraph numbers [0123] to [0132]. The oil-soluble dyes represented by the general formulas (3), (4), (M-1) to (M-2) described in the publication are not only magenta but also other colors such as black ink and red ink. It may be used for ink.

  Examples of cyan oil-soluble dyes include dyes represented by formulas (I) to (IV) of JP-A No. 2001-181547 and paragraph numbers [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) are preferable, and specific examples include paragraph numbers [0052] to [0066] of JP-A No. 2001-181547 and JP-A No. 2002. And the compounds of paragraph Nos. [0079] to [0081] of No. 12214. Particularly preferred dyes are phthalocyanine dyes represented by the general formulas (CI) and (CII) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, and more generally A phthalocyanine dye represented by the formula (C-II) is preferred. Specific examples thereof include compounds described in paragraphs [0198] to [0201] of JP-A No. 2002-121414. The oil-soluble dyes represented by formulas (I) to (IV), (IV-1) to (IV-4), (CI), and (C-II) are not only cyan but also black ink or You may use for inks of other colors, such as green ink.

  As content in the ink composition for inkjet recording of the dye concerning this invention, 0.05-15 mass% is preferable, 0.1-10 mass% is more preferable, Especially 0.2-6 mass% is preferable. .

[Organic boron compounds]
The ink composition for ink jet recording of the present invention contains at least one organic boron compound. The organoboron compound constitutes a photopolymerization initiator by using it together with the above-mentioned “dye having an oxidation potential nobler than 1.0 V (vs SCE)”. It can act on saturated monomers to promote polymerization and curing. That is, in the exposure process at the time of recording, the polymerization reaction is allowed to proceed to a desired degree while efficiently reacting to light belonging to the spectral absorption wavelength region of the dye and controlling the generation of radicals by an arbitrary light source (particularly visible light). be able to. Thereby, the ink composition which comprises an image can be hardened | cured, and the robustness with respect to stickiness of a recorded image, light, ozone, or abrasion can be improved effectively.

  Examples of the organic boron compound include compounds represented by the following general formula (I), and JP-A-62-143044, JP-A-9-188865, JP-A-9-188686, and JP-A-9-188710. And organoboron compounds described in JP-A-2000-319283. Particularly preferred are compounds represented by the following general formula (I).

  In the general formula (I), R represents an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group, a substituted aralkyl group, an alkaryl group, a substituted alkaryl group, an alkenyl group, a substituted alkenyl group, an alkynyl group. , A substituted alkynyl group, an alicythalic group, a substituted alicythalic group, a heterocyclic group, a substituted heterocyclic group, and derivatives thereof, which may be the same as or different from each other. Two or more of these may be linked directly or via a substituent to form a boron-containing heterocycle. X is an alkali metal, quaternary ammonium, pyridinium, quinolinium, diazonium, morpholinium, tetrazolium, acridinium, phosphonium, sulfonium, oxosulfonium, iodonium, S, P, Cu, Ag, Hg, Pd, Fe, Co , Sn, Mo, Cr, Ni, As, and Se.

  Specific examples of the organic boron compound [Exemplary compounds (1) to (36), (A-1) to (A-40), and (B-1) to (B-25)] are listed below. However, the present invention is not limited to these.

  In the present invention, together with the above-described dye according to the present invention, an organic pigment can be used in combination according to the light source wavelength during the exposure process. The organic dye can be appropriately selected from known compounds, and an organic dye having a maximum absorption wavelength at 400 to 1200 nm (preferably 600 to 800 nm) is particularly preferable. Sensitivity can be increased by selecting any desired dye belonging to the wavelength region and adjusting the photosensitive wavelength to match the light source used in the exposure process. Also, the light source is a blue, green, red light source, infrared laser, etc. Can also be selected. Thereby, a plurality of ink compositions having different hues can be selectively or collectively polymerized and cured.

  Specifically, 3-ketocoumarin compound, thiopyrylium salt, naphthothiazole merocyanine compound, merocyanine compound, merocyanine dye containing thiobarbituric acid, hemioxanol dye, cyanine having indolenine nucleus, hemicyanine, merocyanine dye, etc. Disclogure, Vol. 200, December 1980, Item 20036 "and" Sensitizer "(p.160-163, Kodansha; Katsumi Tokumaru, Nobu Okawara, edited by 1987) and the like.

[Other ingredients]
In addition to the ethylenically unsaturated monomer, the dye according to the present invention, and the organic boron compound, the ink composition for inkjet recording of the present invention includes an organic solvent, adjustment of the viscosity and polarity of the composition itself, and polymerization activity. For the purpose of adjustment, a high-boiling hydrophobic organic solvent or polymer can be appropriately contained.

~Organic solvent~
In the ink composition for ink jet recording of the present invention, an organic solvent can generally be used in the case where, for example, colored fine particles are prepared using an emulsifying dispersion method as described later. For example, when an ink composition is formed by dispersing colored fine particles in an aqueous medium, it can be prepared as an oil phase for an aqueous phase (aqueous medium) using an organic solvent together with the monomer, dye and organic boron compound.

  The organic solvent is not particularly limited and is preferably selected based on the solubility of the dye, the monomer, or a polymer that is a polymer of the monomer, and examples thereof include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone. Alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol and tert-butanol, chlorine solvents such as chloroform and methylene chloride, aromatic solvents such as benzene and toluene, ethyl acetate, acetic acid Examples thereof include ester solvents such as butyl and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, and glycol ether solvents such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether.

Two or more organic solvents may be used in combination in addition to being used alone. Further, depending on the solubility of the dye, the monomer or the polymer which is a polymer of the monomer, it can be used as a mixed solvent with water.
There is no restriction | limiting in particular as long as it is in the range which does not inhibit the effect of this invention as the usage-amount of an organic solvent, 10-2000 mass parts is preferable with respect to 100 mass parts of ethylenically unsaturated monomers as stated above. When the amount used is less than 10 parts by mass, fine and stable dispersion of the fine particles tends to be difficult when dispersed, and when it exceeds 2000 parts by mass, a step of desolvation and concentration to remove the organic solvent Tends to be indispensable and complicated, and there is a tendency that there is no allowance for blending design.

  When the vapor pressure of the organic solvent is higher than water, the organic solvent is preferably removed from the viewpoint of stability of the dispersion when dispersed and safety and health. As a method for removing the organic solvent, various known methods can be applied depending on the type of the solvent, and examples thereof include an evaporation method, a vacuum evaporation method, and an ultrafiltration method. The removal of the organic solvent is preferably carried out as soon as possible immediately after emulsification and dispersion when emulsified and dispersed.

  As will be described later, for example, in the case where colored fine particles containing an ethylenically unsaturated monomer, a dye, and an organic boron compound are dispersed in an aqueous medium by an emulsion dispersion method, the colored fine particles in the ink composition for inkjet recording of the present invention are used. The content of is preferably 1 to 45% by mass and more preferably 2 to 30% by mass with respect to the mass of the composition. This content can be appropriately adjusted by dilution, evaporation, ultrafiltration and the like.

The high-boiling organic solvent that can be contained as another component is an organic solvent having a boiling point higher than 100 ° C. The high-boiling organic solvent preferably has a boiling point of 150 ° C. or higher, more preferably 170 ° C. or higher. Examples include polyhydric alcohols, esters of aliphatic carboxylic acids, phosphoric esters, hydrocarbons, and the like. Specific examples include diethylene glycol, trimethylolpropane, dibutyl phthalate, and 2-ethylhexyl benzoate. And alkylnaphthalene. More specific specific examples include hydrophobic high-boiling organic solvents described in Japanese Patent Application No. 2000-78518. These can be either liquid or solid at room temperature depending on the purpose.
A plurality of high-boiling organic solvents may be used in combination in addition to a single use, and the amount used is preferably 0 to 20% by mass, more preferably 0 to 10% by mass.

  Examples of the polymer that can be contained as other components include adjustment of the polarity and viscosity of the colored fine particles and dissolution of the dye (especially oil-soluble dye) when the colored fine particles are prepared containing the monomer, the dye and the organic boron compound. It can be used for improving the property, adjusting the adhesion of the ink composition after polymerization and curing to the recording material, light resistance, and the like. This polymer is preferably highly compatible with dyes and monomers, and has a molecular weight of preferably 50,000 or less, and more preferably 20,000 or less. Examples of the polymer include, for example, vinyl polymer, polyurethane, polyester, and the like. Specifically, polybutyl acrylate, poly (isobutyl methacrylate / hydroxyethyl acrylate) (copolymerization mass ratio 95/5), poly (isopropyl acrylate) / Tetrahydrofurfuryl acrylate) (copolymerization mass ratio 70/30), poly (butyl methacrylate / N-methoxymethylacrylamide) (copolymerization mass ratio 80/20), polybutylacrylate / polydimethylsiloxane block copolymer (copolymer) Polymerization mass ratio 90/10). The polymer may be used singly or in combination. The amount of the polymer used varies depending on the type and amount of the ethylenically unsaturated monomer or dye, but is preferably 0 to 40% by mass. -20% by weight is particularly preferred.

In addition to the above, a storage stabilizer can be further contained. Storage stabilizers suppress undesirable polymerization during storage, such as quaternary ammonium salts, hydroxyamines, cyclic amides, nitriles, substituted ureas, heterocyclic compounds, organic acids, hydroquinones, hydroquinones. Examples include monoethers, organic phosphines, copper compounds, and specifically benzyltrimethylammonium chloride, diethylhydroxylamine, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, citric acid, Examples include hydroquinone monobutyl ether and copper naphthenate.
The amount of the storage stabilizer used is preferably 0.005 to 1% by mass, more preferably 0.01 to 0.5% by mass, and more preferably 0.01 to 0%, based on the ethylenically unsaturated monomer. .2% by weight is particularly preferred.

Next, a method for producing the ink composition for ink jet recording of the present invention will be described.
The ink composition for ink-jet recording of the present invention comprises a non-aqueous (oil-based) ink composition produced by stirring and mixing the above-described ethylenically unsaturated monomer, dye, organic boron compound and other components as necessary. And an aqueous (aqueous) ink composition obtained by dispersing these oil components in an aqueous medium. Examples of the method for producing the latter water-based ink composition include a method (emulsification dispersion method) of emulsifying and dispersing the ethylenically unsaturated monomer. As the emulsification dispersion method, the monomer or the like is emulsified by either adding water to the organic solvent phase containing the monomer, dye and organic boron compound, or adding the organic solvent phase to water. A method of preparing a finely divided colored fine particle dispersion is preferable.

  As the emulsifying and dispersing apparatus used in the emulsifying and dispersing method, a known apparatus such as a simple stirrer or impeller stirring method, an in-line stirring method, a mill method such as a colloid mill, or an ultrasonic method can be used. A high-pressure emulsifying and dispersing apparatus is preferable, and among them, a high-pressure homogenizer is particularly preferable.

  The high-pressure homogenizer has a detailed mechanism described in US Pat. No. 4,533,254, JP-A-6-47264, etc., but as a commercially available apparatus, a Gorin homogenizer (APV GAULIN INC.), A microfluidizer (MICROFLUIDEX INC.), An optimizer (Sugino Machine Co., Ltd.), etc. can be used. In addition, a high-pressure homogenizer equipped with a mechanism for atomizing in an ultrahigh-pressure jet stream as described in US Pat. No. 5,720,551 in recent years is particularly effective for emulsification dispersion in the present invention. DeBEE2000 (BEE INTERNATIONAL LTD.) Is an example of an emulsifying and dispersing apparatus using this ultra-high pressure jet stream.

  The pressure when emulsifying and dispersing using the high-pressure emulsifying dispersion device is preferably 50 MPa or more (500 bar or more), more preferably 60 MPa or more (600 bar or more), and further preferably 180 MPa or more (1800 bar or more). In the present invention, at the time of emulsification and dispersion, for example, it is particularly preferable to use two or more types of emulsifiers together by a method such as emulsification with a stirring emulsifier and then passing through a high-pressure homogenizer. It is also preferable to once emulsify and disperse with these emulsifiers, add additives such as wetting agents and surfactants, and then pass through the high-pressure homogenizer again while filling the ink composition into the cartridge.

  In the emulsification dispersion, when a low boiling point organic solvent is contained in addition to the monomer, it is preferable to substantially remove the low boiling point solvent from the viewpoint of stability of the emulsion and safety and health. As a method for substantially removing the low-boiling organic solvent, various known methods such as an evaporation method, a vacuum evaporation method, and an ultrafiltration method can be employed depending on the type of the low-boiling organic solvent. . The step of removing the low-boiling organic solvent is preferably performed as soon as possible immediately after emulsification.

  In the emulsification dispersion, various surfactants can be used in addition to the above components. For example, fatty acid salt, alkyl sulfate ester salt, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl phosphate ester salt, naphthalene sulfonate formalin condensate, polyoxyethylene alkyl sulfate ester salt, etc. Surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethyleneoxypropylene block Nonionic surfactants such as copolymers, and SURFYNOLS (Air) which is an acetylene-based polyoxyethylene oxide surfactant products & Chemicals), amine oxide type amphoteric surfactants such as N, N-dimethyl-N-alkylamine oxide, and further, pages (37) to (38) of JP-A-59-157636. Research Disclosure No. Preferred are those described in 308119 (1989).

  When emulsifying and dispersing the colored fine particles (oil phase) containing the monomer, dye and organoboron compound in an aqueous medium to form an aqueous ink composition, control of the particle size is particularly important. In order to increase color purity and density when an image is formed by the ink jet recording method, it is preferable to reduce the average particle diameter of the colored fine particles. Specifically, the volume average particle diameter of the colored fine particles is preferably 1 nm or more and 300 nm or less, more preferably 2 nm or more and 200 nm or less, and further preferably 2 nm or more and 100 nm or less. Further, if the colored fine particles have coarse particles, the printing performance may be deteriorated. For example, when the coarse particles clog the nozzles of the head, and even if the clogging is not clogged, the ink may not be ejected or the ejection may be misaligned. Therefore, it is preferable that the ratio of coarse particles is low. Specifically, when the ink is prepared, 10 μl or less of particles of 5 μm or more in 1 μl of ink should be 1000 or less of particles of 1 μm or more. preferable. As a method for removing these coarse particles, a known centrifugal separation method, microfiltration method or the like can be used. These separation means may be performed immediately after the emulsification dispersion, or may be performed immediately after filling the ink dispersion with various additives such as a wetting agent and a surfactant. In order to reduce the average particle diameter of the colored fine particles and reduce the coarse particles, it is effective to use a mechanical emulsifier.

  In addition to the above components, the ink composition for ink jet recording of the present invention, particularly an aqueous ink composition, may contain the following various additives as necessary. Various additives can be contained within a range that does not impair the effects of the present invention. For example, drying inhibitors, penetration enhancers, ultraviolet absorbers, antioxidants, antifungal agents, pH adjusters, surface tension Well-known additives, such as a regulator, an antifoamer, a viscosity modifier, a dispersing agent, a dispersion stabilizer, a rust inhibitor, a chelating agent, are mentioned.

The anti-drying agent can be suitably used for the purpose of preventing clogging due to the dry operation of the ink composition at the ink ejection port of the nozzle used in the ink jet recording system. As the drying inhibitor, a water-soluble organic solvent having a vapor pressure lower than that of water is preferable. Specific examples of the drying inhibitor include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, and acetylene. Polyhydric alcohols typified by glycol derivatives, glycerin, trimethylolpropane, etc., polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether Lower alkyl ethers, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, heterocyclic rings such as N-ethylmorpholine, sulfolane, dimethylsulfone Kishido, sulfur-containing compounds such as 3-sulfolene, diacetone alcohol, polyfunctional compounds such as diethanolamine, and urea derivatives. Among these, polyhydric alcohols such as glycerin and diethylene glycol are more preferable.
These may be used alone or in combination of two or more. These drying inhibitors are preferably contained in the ink composition for ink jet recording in an amount of 10 to 50% by mass.

  The penetration enhancer can be suitably used for the purpose of allowing the ink composition to penetrate better into paper. Examples of the penetration enhancer include alcohols such as ethanol, isopropanol, butanol, di (tri) ethylene glycol monobutyl ether, 1,2-hexanediol, sodium lauryl sulfate, sodium oleate, and a nonionic surfactant. It is done. The penetration enhancer is contained within a range that does not cause printing bleeding, paper loss (print-through), and the like, and is contained in an ink composition for ink-jet recording in an amount of about 5 to 30% by mass. Demonstrate.

  The ultraviolet absorber can be used for the purpose of improving the storability of an image. For example, JP-A Nos. 58-185677, 61-190537, JP-A-2-782, and JP-A-5-97075. Benzotriazole compounds described in JP-A-9-34057, etc., benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194443, US Pat. No. 3,214,463, etc. 48-30492, 56-21114, and cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, and 8-239368. And triazine compounds described in JP-A-10-182621, JP-A-8-501291, etc. Jar No. Examples thereof include compounds described in No. 24239, compounds that emit fluorescence by absorbing ultraviolet rays, such as stilbene and benzoxazole compounds, so-called fluorescent brighteners, and the like.

  The antioxidant can be used for the purpose of improving the storability of the image. For example, various organic and metal complex anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, and the like. Examples of the metal complex-based antifading agent include nickel complexes and zinc complexes. No. 17643, No. VII, I to J, ibid. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .

  Examples of the antifungal agent include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof. These are preferably used in the ink in an amount of 0.02 to 1.00% by mass.

Suitable examples of the surface tension adjusting agent include nonionic, cationic, and anionic surfactants. The surface tension of the ink composition for ink jet recording of the present invention is preferably 25 to 70 mN / m, and more preferably 25 to 60 mN / m.
The viscosity of the ink composition for inkjet recording of the present invention is preferably 30 mPa · s or less, and more preferably 10 mPa · s or less.

  As the antifoaming agent, a fluorine-based compound, a silicone-based compound, a chelating agent typified by EDTA, or the like can be contained as necessary.

  The pH adjuster can be suitably used, for example, in terms of adjusting pH and imparting dispersion stability when a colored fine particle dispersion is prepared by an emulsifying dispersion method, so that the pH becomes 4.5 to 10.0. It is preferable to add, and it is more preferable to add so that it may become pH 6-10.0. The pH adjuster is preferably an organic base or inorganic alkali as a basic one, and an organic acid or inorganic acid or the like as an acidic one. In the basic pH adjuster, among the organic bases, triethanolamine, diethanolamine, N-methyldiethanolamine, dimethylethanolamine and the like are more preferable. Among the inorganic alkalis, alkali metal hydroxides, carbonates, Ammonia and the like are more preferable. Among the alkali metal hydroxides, sodium hydroxide, lithium hydroxide, potassium hydroxide, and the like are particularly preferable. Among the carbonates, sodium carbonate, sodium bicarbonate, and the like are particularly preferable. In the acidic pH adjuster, acetic acid, propionic acid, trifluoroacetic acid, alkylsulfonic acid and the like are more preferable among the organic acids, and hydrochloric acid, sulfuric acid, phosphoric acid and the like are more preferable among the inorganic acids.

The ink composition for ink jet recording of the present invention can be suitably used as an ink for ink jet recording. There are no particular restrictions on the ink jet recording method, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electrical signal that is acoustic Either an acoustic ink jet system that irradiates ink by irradiating it with ink instead of using a beam, or a thermal ink jet system that uses ink to form bubbles by heating the ink and use the generated pressure. Also good. The inkjet recording method includes a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent. A method using ink.
Among the above, the ink is suitable for ink jet recording such as thermal type, piezoelectric type, electrolytic type, or acoustic type.

<Image forming method>
The image forming method of the present invention comprises a step of recording an image on a recording material (recording step) using the ink composition for ink jet recording of the present invention described above, and light (particularly visible light) on the recorded image. It is comprised by the process (exposure processing process) which is irradiated and hardened. In the present invention, after an image is recorded on the recording material in the recording process, the ethylenically unsaturated monomer is polymerized and cured by irradiating the recorded image with light (particularly visible light) in the exposure processing process, whereby the stickiness is reduced. Therefore, it is possible to form an image with high image quality and high fastness to light, ozone, abrasion, and the like.

  In the recording process, it is preferable to apply an inkjet recording method using an inkjet printer. In the ink jet recording method, image recording is performed on a recording material using the ink composition for ink jet recording of the present invention, and there are no particular restrictions on the ink discharge nozzles used at that time, and it is appropriately selected according to the purpose. can do. The recording material will be described later. Moreover, there is no restriction | limiting in particular in an inkjet recording system, and it is as above-mentioned specifically.

  In the exposure processing step, the exposure processing for accelerating polymerization and curing can be performed using a light source that emits light in a wavelength region corresponding to the sensitive wavelength of the dye according to the present invention described above (and possibly an organic pigment). . Specifically, it can be suitably performed using a light source that emits light belonging to a wavelength region of 300 to 1200 nm, particularly a wavelength region of 600 to 800 nm, such as a fluorescent lamp, an LD, and an LED. What is necessary is just to select an exposure time and a light quantity suitably according to the grade of the polymerization hardening of an ethylenically unsaturated monomer, and about 30 second is common.

[Recording material]
The recording material is not particularly limited, and examples thereof include known recording materials such as plain paper, resin-coated paper, inkjet recording paper, film, electrophotographic co-paper, fabric, glass, metal, and ceramics. Among these, paper for exclusive use of inkjet recording is preferable. For example, JP-A-8-169172, JP-A-8-27693, JP-A-2-276670, JP-A-7-276789, JP-A-9-323475, JP-A-62-238783, JP-A-10-153898, JP-A-10-217473, JP-A-10-235995, JP-A-10-337947, JP-A-10-217597, JP-A-10-337947 Those described in, etc. are more preferred.

  In the present invention, among the recording materials, the following recording paper and recording film are particularly preferable. The recording paper and the recording film can be formed by providing an ink receiving layer on a support and further laminating other layers such as a backcoat layer as necessary. Each layer including the ink receiving layer may be a single layer or two or more layers.

The support is composed of chemical pulp such as LBKP and NBKP, mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP, and CGP, and waste paper pulp such as DIP. , Binders, sizing agents, fixing agents, cationic agents, paper strength enhancing agents, etc. can be added and mixed, and those manufactured in various devices such as long net paper machines, circular net paper machines, synthetic papers, etc. can be used. In addition to these, a plastic film sheet or the like may be used.
The thickness of the support is preferably about 10 to 250 μm, and the basis weight is preferably 10 to 250 g / m ² .

  The support may be provided with a size press or an anchor coat layer with starch, polyvinyl alcohol or the like, and then with the ink receiving layer and the back coat layer. The support may be flattened by a calendar device such as a machine calendar, a TG calendar, or a soft calendar.

  Among the supports, paper and plastic film sheets that are laminated on both sides with polyolefin (for example, polyethylene, polystyrene, polyethylene terephthalate, polybutene, and copolymers thereof) are preferably used. It is more preferable to add a white pigment (for example, titanium oxide, zinc oxide, etc.) or a tinting dye (for example, cobalt blue, ultramarine blue, neodymium oxide, etc.) to the polyolefin.

The ink receiving layer may contain a pigment, an aqueous binder, a mordant, a water resistance agent, a light resistance improver, a surfactant, and other additives.
The pigment is preferably a white pigment, and examples of the white pigment include calcium carbonate, kaolin, talc, clay, diatomaceous earth, synthetic amorphous silica, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, alumina, Preferable examples include inorganic white pigments such as lithopone, zeolite, barium sulfate, calcium sulfate, titanium dioxide, zinc sulfide and zinc carbonate, and organic pigments such as styrene pigment, acrylic pigment, urea resin and melamine resin. Among these white pigments, porous inorganic pigments are preferable, and synthetic amorphous silica having a large pore area is more preferable. As the synthetic amorphous silica, both anhydrous silicic acid obtained by a dry production method and hydrous silicic acid obtained by a wet production method can be used, but it is particularly preferable to use hydrous silicic acid.

  Examples of the aqueous binder include water-soluble polymers such as polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyalkylene oxide, and polyalkylene oxide derivatives. And water dispersible polymers such as styrene butadiene latex and acrylic emulsion. These aqueous binders may be used alone or in combination of two or more. Among these, polyvinyl alcohol and silanol-modified polyvinyl alcohol are preferable in terms of adhesion to the pigment and peel resistance of the ink receiving layer.

  The mordant is preferably immobilized. For that purpose, a polymer mordant is preferably used. Examples of the polymer mordant include JP-A Nos. 48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, 60-23835, 60-23852, 60-23835, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122942, 60 -235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, 4,273,853, 4,282,305 Are described in each specification of US Pat. No. 4,450,224. A polymer mordant described on pages 212 to 215 of JP-A-1-161236 is particularly preferred. When the polymer mordant described in the publication is used, an image with excellent image quality is obtained and the light resistance of the image is improved.

  The water-proofing agent is effective for making the image water-resistant, and a cationic resin is preferable. Examples of the cationic resin include polyamide polyamine epichlorohydrin, polyethyleneimine, polyamine sulfone, dimethyldiallylammonium chloride polymer, cationic polyacrylamide, colloidal silica, and the like. Among these, polyamide polyamine epichlorohydrin is particularly preferable. The content of the cationic resin is preferably 1 to 15% by mass and more preferably 3 to 10% by mass with respect to the total solid content of the ink receiving layer.

  Examples of the light resistance improver include zinc sulfate, zinc oxide, hindered amine antioxidants, benzophenone and benzotriazole ultraviolet absorbers, and among these, zinc sulfate is particularly preferable.

  The surfactant functions as a coating aid, a peelability improver, a slippage improver or an antistatic agent. Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. An organic fluoro compound may be used in place of the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compound include a fluorine surfactant, an oily fluorine compound (for example, fluorine oil) and a solid fluorine compound resin (for example, tetrafluoroethylene resin). The organic fluoro compounds are described in JP-B-57-9053 (columns 8 to 17), JP-A-61-2994, and JP-A-62-135826.

  Examples of other additives include pigment dispersants, thickeners, antifoaming agents, dyes, fluorescent whitening agents, preservatives, pH adjusting agents, matting agents, and hardening agents.

  The back coat layer can contain a white pigment, an aqueous binder, and other components. Examples of white pigments include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, Magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide, white inorganic pigment, styrene plastic pigment, acrylic Examples thereof include organic pigments such as plastic pigment, polyethylene, microcapsule, urea resin, and melamine resin.

  Examples of the aqueous binder in the backcoat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxymethylcellulose, hydroxy Examples thereof include water-soluble polymers such as ethyl cellulose and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion. Examples of the other components in the backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a waterproofing agent.

  A polymer latex may be added to the constituent layers (including the backcoat layer) in the recording paper and recording film. The polymer latex is used for the purpose of improving film physical properties such as dimensional stabilization, curling prevention, adhesion prevention, and film cracking prevention. The polymer latex is described in JP-A Nos. 62-245258, 62-136648, and 62-110066. When a polymer latex having a low glass transition temperature (40 ° C. or lower) is added to the layer containing the mordant, cracking and curling of the layer can be prevented. Further, curling can be prevented by adding a polymer latex having a high glass transition temperature to the back coat layer.

  In the image forming method of the present invention, the recording material is not particularly limited, but an ink receiving layer is provided on a support, and the ink receiving layer contains a white pigment (porous inorganic pigment). This is most preferable in that a high-quality image can be formed when a material is used. In addition, in many conventional dispersed inks, when a recording material having an ink receiving layer containing a porous inorganic pigment such as a white pigment is used, the permeation into the recording material is poor, and the formed image is Although there was a problem that the dye peeled off from the surface when rubbed by hand, the ink composition for inkjet recording of the present invention is composed of an ethylenically unsaturated monomer, a dye and an organic boron compound (for example, a colored fine particle dispersion). It is low viscosity and oily and has excellent penetration, so this problem is solved and discharge stability from the discharge nozzle during printing is excellent. Since the unsaturated monomer is polymerized, the colored fine particles are changed to colored fine particles composed of a dye and a polymer to improve image fastness, in particular, light fastness, ozone resistance and scratch resistance of the image. It can be. Thereby, according to the image recording using the ink composition for inkjet recording of the present invention, an image having high image quality, high strength and excellent image fastness can be formed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, ink for inkjet recording is prepared as an example of the ink composition, and “parts” and “%” in the examples are based on mass unless otherwise specified.

Example 1
The following composition components were stirred and mixed to prepare the magenta ink 101 for non-aqueous ink jet recording of the present invention.
-Composition-
N-butyl acrylate and t-butyl acrylamide [ratio = 50: 50; monomer (raw material of exemplified polymer PA-11 after polymerization)] 3.0 g
・ DPCA60 (Nippon Kayaku Co., Ltd.) ... 1.0g
・ 1,6-Hexanediol diacrylate (HDDA, manufactured by Daicel UC Corporation) 16.0 g
・ N-ethyldiethanolamine 0.6g
-Illustrative compound A-12 of the organic boron compound described above 0.42 g
・ The following oil-soluble dye M-1: 0.8 g

(Examples 2-9, Comparative Examples 1-4)
In Example 1, except that the oil-soluble dye, the types of monomers and organic boron compounds as raw materials for polymer formation, and the ratio of the organic boron compound to the monomer were changed as shown in Table 1 below, respectively. Similarly, non-aqueous ink jet recording magenta inks 102 to 109 of the present invention and comparative non-aqueous ink jet recording magenta inks 110 to 113 were produced.

  The oxygen permeability coefficient of the polymer after polymerization (see Table 1 below) was measured by the same method as in the case of the exemplified polymer PA-1 (Synthesis Example 1) described above.

(Evaluation 1)
The non-aqueous ink jet recording magenta inks 101 to 113 obtained as described above are sequentially filled into a cartridge of an ink jet printer (an experimental machine manufactured by Microjet), and the same machine (print density: 300 dpi, droplet ejection frequency: 4 KHz, number of nozzles: 64), the image was recorded on the art paper so that the density (OD) = 1.0, and the recorded image was exposed and exposed under the exposure conditions shown in Table 2 below. The following evaluations were performed on the images. The evaluation results are shown in Table 2 below.

1. Evaluation of printing performance Each cartridge was set in a printer, and after confirming the ejection of ink from all nozzles, images were output to 10 sheets of A4 size, and the disturbance of the printed image was evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: There was no disorder in printing from the start to the end of printing.
B: Disturbance of printing occasionally occurred from the start to the end of printing.
C: Disturbance of printing was recognized from the start to the end of printing.

2. Evaluation of Stickiness The printed surface was touched with a finger, and the case where there was no stickiness was designated as A, the case where there was slightly stickiness as B, and the case where there was marked stickiness as C.

3. Evaluation of scratch resistance After image printing and exposure processing on art paper, each art paper after 30 minutes was rubbed back and forth 10 times with an eraser to observe the density change of the printed part, and no density reduction occurred in the image. Three cases were evaluated as A, A with a slight decrease in density as B, and C with a significant decrease in density as C.

4). Evaluation of light fastness For each art paper on which images were recorded, the density (D ¹ ) of each image was measured in advance using a reflection densitometer (X-Rite 310TR, manufactured by X-Rite), and each art paper The paper was irradiated with xenon light (85,000 lux) for 4 days using a weather meter (Atlas Ci 65), and the image density (D ² ) after irradiation was measured in the same manner as described above. The dye residual ratio (%; D ² / D ¹ × 100) was determined from the measured concentrations D ¹ and D ² and used as an index for evaluating light resistance. The reflection density D ¹ before irradiation was measured by fixing to 1.0. The evaluation is A when the dye residual ratio is 90% or more, B as 89-80%, C as 79-70%, D as 69-50%, and less than 49%. The case was evaluated as E, and a five-step evaluation was performed.

5. Evaluation of ozone resistance For each of the art papers on which the images were recorded, the density (D ³ ) of each image was measured in advance using a reflection densitometer (X-Rite 310TR, manufactured by X-Rite). Art paper was stored for 3 days under the condition of ozone concentration of 5.0 ppm, and the image density (D ⁴ ) after storage was measured in the same manner as described above. A dye residual ratio (%; D ⁴ / D ³ × 100) was determined from the measured concentrations D ³ and D ⁴ and used as an index for evaluating ozone resistance. The evaluation is A when the dye residual ratio is 90% or more, B as 89-80%, C as 79-70%, D as 69-50%, and less than 49%. The case was evaluated as E, and a five-step evaluation was performed.

As shown in Table 2 above, the magenta ink for non-aqueous ink jet recording of the present invention prepared so that it can be polymerized even by irradiation with visible light has a visible exposure condition in spite of a small amount of an organic boron compound. Under these conditions, the polymerization reaction was carried out efficiently and quickly, and an image having excellent printing performance, no stickiness, and high scratch resistance, light resistance, and ozone resistance could be obtained. Further, in the case of the configuration (Example 9) in which the oxygen permeability coefficient exceeds 2.6 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)], the curing reaction is rapid, but the recording It was slightly inferior to the other examples in terms of the subsequent stickiness and image fastness. On the other hand, in the comparative example using an organic boron compound sensitive to visible light or using Irgacure 1870 which is a UV-sensitive polymerization initiator, polymerization curing with a fluorescent lamp (exposure condition 1) is insufficient. It was difficult to improve the stickiness after recording, scratch resistance, light resistance, and ozone resistance. In order to obtain the same results as in the examples, it was necessary to perform ultraviolet irradiation with high energy (exposure condition 2).

(Example 10)
4 g of n-butyl acrylate and t-butyl acrylamide [ratio = 50: 50; monomer (raw material of polymer PA-11 after polymerization)], 0.45 g of the oil-soluble dye M-1, and N-ethyldiethanolamine 0.04 g and 0.24 g of the exemplified compound A-12 of the organic boron compound described above were mixed and dissolved in 17 g of ethyl acetate to obtain an ethyl acetate solution. On the other hand, a mixed solution of 18 g of water and 0.4 g of Emar 20C (manufactured by Kao Corporation) was prepared. This mixed solution was combined with the above ethyl acetate solution, and the resulting solution was emulsified with a homogenizer at 10,000 rpm for 4 minutes and then stopped for 1 minute for 5 cycles. . Then, it concentrated at 30 degreeC under pressure reduction, and prepared the colored fine particle dispersion of 25.2% of solid content. The particle size of the colored fine particles in the colored fine particle dispersion was 88 nm in terms of volume average particle size.

Subsequently, the colored fine particle dispersion obtained above and the following material were mixed and filtered using a 0.45 μm filter to prepare a magenta ink 201 for water-based inkjet recording.
-Colored fine particle dispersion 60 parts-Diethylene glycol ... 5 parts-Glycerin ... 15 parts-Diethanolamine ... 1 part-Olphine E1010 ... 1.1 parts-Water ... Amount to be 100 parts in total

(Examples 11-18, Comparative Examples 5-8)
In Example 10, except that the oil-soluble dye, the monomer that is a raw material for polymer formation, the type of the photopolymerization initiator organic boron compound, and the ratio of the organic boron compound to the monomer were changed as shown in Table 3 below. In the same manner as in Example 10, aqueous ink jet recording magenta inks 202 to 109 of the present invention and comparative aqueous ink jet recording magenta inks 210 to 213 were produced.

In Examples 10 to 18 and Comparative Examples 5 to 8, the amount of the organic boron compound was used so as to be 10% (mass ratio) or less with respect to the amount of the ethylenically unsaturated monomer. Moreover, in the water-based inkjet recording inks 201 to 213, the concentrations of diethylene glycol, glycerin, and other additives in the finally obtained ink are constant.
Further, the oxygen permeability coefficient (see Table 3 below) of the polymer after polymerization was measured by the same method as in the case of the exemplified polymer PA-1 (Synthesis Example 1) described above.

(Evaluation 2)
Magenta inks 201 to 213 for water-based inkjet recording obtained as described above are sequentially filled into a cartridge of an inkjet printer PX-V700 (manufactured by Seiko Epson Corporation), and the same machine is used to create inkjet paper photo glossy paper “Image” ( After recording an image on Fuji Photo Film Co., Ltd., the recorded image was exposed under the exposure conditions shown in Table 2 below, and the following evaluation was performed on the image after the exposure processing. The evaluation results are shown in Table 4 below.

1. Evaluation of printing performance Each cartridge was set in a printer, and after confirming the ejection of ink from all nozzles, images were output to 10 sheets of A4 size, and the disturbance of the printed image was evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: There was no disorder in printing from the start to the end of printing.
B: Disturbance of printing occasionally occurred from the start to the end of printing.
C: Disturbance of printing was recognized from the start to the end of printing.

2. Evaluation of stickiness Touching the printed surface with a finger, if there is no stickiness, it is A (good), and there is a little stickiness, but it is B (permissible) that does not stain the contacted object. Was evaluated as a C (defect) in three stages.

3. Evaluation of scratch resistance After image printing and exposure on art paper, each art paper after 30 minutes was rubbed back and forth 10 times with an eraser to observe the density change of the printed part, and no density change occurred in the image. The evaluation was made as A (good), B (allowable) when the density change slightly occurred, and C (bad) when the density change was recognized remarkably.

4). Evaluation of Light Resistance For each photo glossy paper on which images were recorded, the density (D ⁵ ) of each image was previously measured using a reflection densitometer (X-Rite 310TR, manufactured by X-Rite), Photo glossy paper was irradiated with xenon light (85,000 lux) through a TAC filter for 7 days using a weather meter (Atlas Ci65), and the image density (D ⁶ ) after irradiation was measured in the same manner as described above. The dye residual ratio (%; D ⁶ / D ⁵ × 100) was determined from the measured concentrations D ⁵ and D ⁶ and used as an index for evaluating light resistance. The reflection density D ⁵ before irradiation was fixed at 1.0 and measured. The evaluation was performed in three stages, with A as the residual ratio of 85% or more, B as 70 to less than 85, and C as less than 70%.

5. Evaluation of ozone resistance For each of the photo glossy papers on which the images were recorded, the density (D ⁷ ) of each image was measured in advance using a reflection densitometer (X-Rite 310TR, manufactured by X-Rite). The photo glossy paper was stored for 3 days under the condition of ozone concentration of 5.0 ppm, and the image density (D ⁸ ) after storage was measured in the same manner as described above. The dye residual ratio (%; D ⁸ / D ⁷ × 100) was determined from the measured concentrations D ⁷ and D ⁸ and used as an index for evaluating ozone resistance. The evaluation is A when the dye residual ratio is 90% or more, B as 89-80%, C as 79-70%, D as 69-50%, and less than 49%. The case was evaluated as E, and a five-step evaluation was performed.

As shown in Table 4 above, the magenta ink for non-aqueous ink jet recording of the present invention prepared so that it can be polymerized even by irradiation with visible light has a visible exposure condition in spite of a small amount of an organic boron compound. Under these conditions, the polymerization reaction was carried out efficiently and quickly, and an image having excellent printing performance, no stickiness, and high scratch resistance, light resistance, and ozone resistance could be obtained. Further, in the configuration in which the oxygen permeability coefficient exceeds 2.6 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] (Example 9), the curing reaction is rapid, but after recording. The stickiness and image fastness were slightly inferior to those of the other examples. On the other hand, in the comparative example using an organic boron compound sensitive to visible light or using Irgacure 1870 which is a UV-sensitive polymerization initiator, polymerization curing with a fluorescent lamp (exposure condition 1) is insufficient. It was difficult to improve the stickiness after recording, scratch resistance, light resistance, and ozone resistance. In order to obtain the same results as in the examples, it was necessary to perform ultraviolet irradiation with high energy (exposure condition 2).

Claims (4)

  An ink composition for ink-jet recording, comprising at least an ethylenically unsaturated monomer, a dye having an oxidation potential nobler than 1.0 V (vs SCE), and an organic boron compound. The ethylenically unsaturated monomer is a polymer having an oxygen permeability coefficient at 25 ° C. of 2.6 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less by a polymerization reaction. The ink composition for ink jet recording according to claim 1, which is a constituting compound.   The ink composition for inkjet recording according to claim 1 or 2, wherein a solution containing at least the ethylenically unsaturated monomer, the dye, and the organoboron compound is emulsified and dispersed in an aqueous medium.   A step of recording an image on a recording material using the ink composition for ink jet recording according to any one of claims 1 to 3, and a step of irradiating the recorded image with light to cure the image. An image forming method.