JP2015209513A - Ink, ink cartridge and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink capable of suppressing a bronzing phenomenon and improving ozone resistance of an image at a high level and having excellent glossiness of an image and excellent storage stability of an ink.SOLUTION: There is provided an inkjet ink in which a special phthalocyanine-based pigment is used as a pigment, the urethane resin has a unit derived from a polyisocyanate having a monocyclic aliphatic ring and a unit derived from a polyol and the molar ratio of the unit derived from a polyisocyanate having a monocyclic aliphatic ring to all of the units derived from a polyisocyanate, the number average molecular weight of the unit derived from a polyol, the acid value of the urethane resin and the mass ratio between the content of the urethane resin and the content of the phthalocyanine-based compound are within a predetermined range.

Description

  The present invention relates to an ink, an ink cartridge, and an ink jet recording method.

  Inkjet recording methods are easy to achieve full color, and high-definition images comparable to silver salt photographs and offset printing can be obtained at a relatively low price. In the inkjet recording method, generally, cyan, magenta, yellow, and optionally added black ink are used. As a coloring material for cyan ink, a copper phthalocyanine compound is widely used because of its high coloring power. A major problem when an image is recorded using this phthalocyanine compound as a coloring material is that the image appears reddish due to a so-called bronze phenomenon. This phenomenon is remarkably recognized in a recording medium such as glossy paper whose color material is likely to be present on the surface and whose surface is smooth. Further, since the ozone resistance of the image is low, discoloration and hue change occur during long-term storage, and accordingly, the color balance with other color materials is lost.

  In general, when a phthalocyanine-based dye is used as a coloring material, there is a problem that the bronzing phenomenon hardly occurs due to the weak association force between the dye molecules, but the ozone resistance of the image is lowered. Solutions to such problems include the introduction of strong electron-withdrawing groups into the copper phthalocyanine skeleton of dye molecules, the introduction of association promoting groups into the copper phthalocyanine skeleton, and the addition of association control agents to dye inks. Techniques are known. Further, a dye ink in which a specific amine such as polyamine or heterocyclic amine is added to a phthalocyanine dye is disclosed (see Patent Document 1).

  On the other hand, when a phthalocyanine-based pigment is used as a color material, since the pigment molecules exist in an associated state, the ozone resistance of the image is relatively good, but there is a problem that the bronze phenomenon becomes remarkable. As a solution to such a problem, an ink containing a copper phthalocyanine pigment and a urethane resin has been disclosed (see Patent Document 2). In addition, an ink is disclosed in which a phthalocyanine compound whose central metal is silicon, germanium, tin, or the like is dispersed by a styrene-acrylic acid copolymer (see Patent Document 3). Furthermore, a method of overlaying a colorless ink containing a styrene-acrylic acid copolymer on an image recorded with an ink containing a copper phthalocyanine pigment is disclosed (see Patent Document 4).

  Furthermore, in an ink containing a phthalocyanine pigment, there is a problem of improving the glossiness of an image and the storage stability of the ink, which are important basic characteristics of the ink. As a solution to such a problem, a pigment ink in which a phthalocyanine pigment is dispersed with an acid group-containing polyether urethane resin having a poly (oxytetramethylene) structure and an acid value of 40 to 90 is disclosed. (See Patent Document 5).

Special table 2008-536962 gazette JP 2005-532437 A JP 2009-126960 A JP 2009-197211 A JP 2005-290044 A

  However, as a result of the study by the present inventors, it was not possible to achieve a high level of suppression of bronzing and ozone resistance of an image using any of the above-described methods. Further, it has been clarified that none of the above-described methods achieves the required levels of image glossiness and ink storage stability.

  For example, the above-described technique for introducing an electron-withdrawing group into a copper phthalocyanine skeleton is intended to improve the oxidation potential of dye molecules and improve the ozone resistance of an image. In addition, the method of introducing an association promoting group into the copper phthalocyanine skeleton or adding an association control agent to the dye ink enhances the association force between the dye molecules to physically protect the association, and makes the association control agent a sacrificial substance for ozone. This is intended to improve the ozone resistance of the image. However, even if these methods are used, the size of the dye aggregate is small and the interaction between molecules is small as compared with the pigment particles. Therefore, it was found that even if the association controlling agent acts as a sacrificial substance for ozone, the ozone resistance of the image does not reach the required level.

  The dye ink described in Patent Document 1 attempts to improve the ozone resistance of an image by forming an association of the molecules by van der Waals force or ion attractive force between the dye molecule and the amine molecule. It is. However, it was found that the ozone resistance of the image does not reach the required level for the dye ink.

  Further, the pigment ink described in Patent Document 2 attempts to suppress the bronzing phenomenon by adding a certain amount or more of urethane resin to the copper phthalocyanine pigment. However, it has been found that the pigment ink has an effect of suppressing the bronze phenomenon when the pigment content is low, but hardly shows an effect when the pigment content is high. Further, in the pigment ink, no attention is paid to the composition and physical properties of the urethane resin to be used, and further to what effect the addition of the urethane resin has on the ozone resistance of the image. Furthermore, even when an image is recorded on a recording medium such as glossy paper that has a smooth surface and requires improved glossiness of the image, the glossiness of the image does not reach the required level, and ink storage stability Was found to be insufficient.

  In addition, the ink described in Patent Document 3 has both a high level of suppression of bronzing and ozone resistance of an image by dispersing a phthalocyanine compound whose central metal is silicon or the like with a styrene-acrylic acid copolymer. It is about to try. However, although the ink can suppress the bronzing phenomenon, it has been found that sufficient performance is not ensured with respect to ozone resistance. Furthermore, even when an image is recorded on a recording medium such as glossy paper that requires improvement in glossiness, it has been found that the glossiness of the image does not reach the required level and the ink storage stability is insufficient. .

  In addition, the method described in Patent Document 4 attempts to suppress the bronzing phenomenon by overlaying a colorless ink containing a styrene-acrylic acid copolymer on an image recorded with an ink containing a copper phthalocyanine pigment. Is. However, the method requires the use of colorless ink in addition to normal ink, and thus has a problem such as complicated recording control. In addition, it has been found that when an image is recorded on a recording medium having high permeability such as art paper, the resin in the colorless ink easily penetrates into the recording medium and the bronzing phenomenon cannot be suppressed.

  Furthermore, the pigment ink described in Patent Document 5 is a specific polyether-based urethane resin having a poly (oxytetramethylene) structure, and by dispersing a phthalocyanine-based pigment, the glossiness of the image and the initial pigment dispersibility. It tries to make both. However, it has been found that the pigment ink is not significantly different in glossiness of the image from the ink containing a resin having a poly (oxyethylene) structure described in the comparative example. That is, in Patent Document 5, glossiness is compared with inks having different dispersed particle diameters, and when compared with equivalent dispersed particle diameters, only a resin having a poly (oxytetramethylene) structure is significantly superior. It was found that it does not give a high gloss.

  Therefore, the object of the present invention is to achieve both a high level of suppression of bronzing and ozone resistance of an image, and furthermore, glossiness of an image recorded on a recording medium such as glossy paper and storage stability of ink. It is to provide excellent ink.

（前記一般式（１）中、Ｍは金属原子を表す。Ａはそれぞれ独立に、芳香環、又は複素環を表す。Ｚはそれぞれ独立に、炭素数６乃至１８のアリールオキシ基、炭素数１乃至２２のアルコキシ基、又は−ＯＳｉＲ₁Ｒ₂Ｒ₃を表し、Ｒ₁、Ｒ₂、及びＲ₃はそれぞれ独立に、炭素数１乃至２２のアルキル基、炭素数６乃至１８のアリール基、炭素数１乃至２２のアルコキシ基、又は炭素数６乃至１８のアリールオキシ基を表す。） According to the present invention, there is provided an inkjet ink containing a pigment and a urethane resin, wherein the pigment contains a compound represented by the following general formula (1), and the urethane resin is a monocyclic fat. A unit derived from a polyisocyanate having at least a unit derived from a polyisocyanate having a ring or a monocyclic aromatic ring, and a unit derived from a polyol, and derived from a polyisocyanate having the monocyclic aliphatic ring or monocyclic aromatic ring The molar ratio to the units derived from all the polyisocyanates in the urethane resin is 0.85 times or more, the number average molecular weight of the units derived from the polyol is from 850 to 3,000, and the urethane The acid value of the resin is 50 mgKOH / g or more and 85 mgKOH / g or less, and the content (mass%) of the urethane resin is In the mass ratio of the content (mass%) of the compound represented by the general formula (1), an ink which is characterized in that 1.00 times 0.25 times it is provided.
General formula (1):

(In the general formula (1), M represents a metal atom. Each A independently represents an aromatic ring or a heterocyclic ring. Each Z independently represents an aryloxy group having 6 to 18 carbon atoms or 1 carbon atom. Represents an alkoxy group having from 22 to 22 or —OSiR ₁ R ₂ R ₃ , and R ₁ , R ₂ , and R ₃ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, carbon Represents an alkoxy group having 1 to 22 carbon atoms or an aryloxy group having 6 to 18 carbon atoms.)

  According to the present invention, both suppression of bronzing and ozone resistance of an image can be achieved at a high level, and the glossiness of an image recorded on a recording medium such as glossy paper, storage stability of ink, and the like can be achieved. An excellent ink can be provided.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments for carrying out the invention. In the following description, C.I. I. Is an abbreviation for color index. Ink jet ink may be referred to as “ink”.

  The ink of the present invention is an ink jet ink containing a pigment and a urethane resin. As the pigment, the compound represented by the general formula (1) is used. Further, as the urethane resin, a resin having at least a unit derived from a polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring and a unit derived from a polyol is used. Furthermore, the molar ratio of the unit derived from the polyisocyanate having a monocyclic aliphatic ring or monocyclic aromatic ring to the unit derived from all the polyisocyanates in the urethane resin is 0.85 times or more. is there. In addition, the number average molecular weight of the unit derived from the polyol is from 850 to 3,000, and the acid value of the urethane resin is from 50 mgKOH / g to 85 mgKOH / g. And the content (mass%) of the said urethane resin in the said ink is a mass ratio with respect to content (mass%) of the compound represented by the said General formula (1), and is 0.25 times or more and 1.00. It has the characteristic of being less than twice. It has been clarified that the above-described effect can be obtained by the ink having such a configuration.

  By the above features, it is possible to achieve both a suppression of bronze phenomenon and ozone resistance of the image at a high level, and the glossiness of the recorded image and the storage stability of the ink can be improved to the required level. The present inventors consider as follows.

  C.I. which has been conventionally used as a pigment for cyan ink. I. When an image is recorded with an ink containing a copper phthalocyanine pigment such as CI Pigment Blue 15: 3, a remarkable bronze phenomenon is confirmed. This is because the copper phthalocyanine molecule has a planar structure and easily takes a crystal structure having a regular arrangement due to the interaction between the phthalocyanine rings.

  On the other hand, when an image is recorded with the ink containing the compound represented by the general formula (1), the bronze phenomenon is greatly suppressed. This is because when the compound represented by the general formula (1) has an axial ligand, the chromophore density per unit volume of the pigment molecule is lowered, the light transmission component is increased, and the total reflection component is increased. This is thought to be due to the decline. In addition, the compound represented by the general formula (1) having an axial ligand, which weakens the interaction between the phthalocyanine molecules, is considered to be one of the causes for suppressing the bronze phenomenon. However, the details are unknown.

  On the other hand, since the compound represented by the general formula (1) has an axial ligand, a gap between phthalocyanine rings is increased, and an interaction between molecules is also weakened. Therefore, the compound represented by the general formula (1) is easily attacked by ozone molecules, and the ozone resistance of the image tends to be lowered. That is, in the compound represented by the general formula (1), it was found that the suppression of the bronze phenomenon and the improvement of the ozone resistance of the image are in a trade-off relationship.

  As a result of investigations by the present inventors in response to such results, the conventional technology has been developed by optimizing the type of resin used with the compound represented by the general formula (1), its constituent units, and physical properties. It was found that this problem can be solved. The above-described method makes it possible to achieve both high levels of suppression of bronzing and ozone resistance of the image, and improve the glossiness of the image and the storage stability of the ink to the required levels. It came to be completed.

  Specifically, a urethane resin having at least a unit derived from a polyisocyanate having a monocyclic alicyclic ring and a unit derived from a polyol is used. Furthermore, the ratio of the unit derived from the polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring to the unit derived from all the polyisocyanates in the urethane resin is a certain level or more. With these configurations, the ozone resistance of the image was improved. This is because a gap is formed on the surface of the pigment particle composed of the compound represented by the general formula (1) due to the steric hindrance of the axial ligand, and the urethane resin easily interacts with this gap. This is probably because of this. Specifically, in the urethane resin, the monocyclic portion of the unit derived from the polyisocyanate having the monocyclic aliphatic ring or monocyclic aromatic ring, and the urethane bonding group or urea bonding group of the urethane resin The structure is likely to interact with the gap.

  Moreover, the ozone resistance of the image also improved by setting the number average molecular weight of the unit derived from the polyol constituting the urethane resin within a certain range. This is, in the urethane resin, the arrangement of the monocyclic portion of the unit derived from the polyisocyanate having the monocyclic alicyclic ring or monocyclic aromatic ring, and the arrangement of the urethane bonding group or urea bonding group is optimized. This is probably because the structure easily interacts with the gap. Furthermore, by keeping the number average molecular weight of the unit derived from the polyol within a certain range, the strength and flexibility of the film formed of the urethane resin are maintained in a well-balanced state, and the film has good film properties. It becomes easy to adsorb on the surface of the pigment particles. As a result, it is considered that the ozone resistance of the image is improved.

  Further, by setting the acid value of the urethane resin within a certain range, the glossiness of the image is improved to a required level. In the recording medium, the surface energy of the ink droplet containing urethane resin is increased, so that the next recorded ink droplet spreads on the surface of the image, and unevenness on the surface of the image is easily reduced. In addition, by setting the acid value of the urethane resin in the above range, it is considered that rapid aggregation of the pigment is suppressed, and as a result, the glossiness of the image is improved to a required level.

  In addition, by setting the acid value of the urethane resin within a certain range, the storage stability of the ink was improved to a required level. This is presumably because the urethane resin balances the adsorptivity to the surface of the pigment particles and the affinity to the liquid medium constituting the ink at a high level.

<Ink>
Hereinafter, components constituting the ink of the present invention will be described in detail.

（前記一般式（１）中、Ｍは金属原子を表す。Ａはそれぞれ独立に、芳香環、又は複素環を表す。Ｚはそれぞれ独立に、炭素数６乃至１８のアリールオキシ基、炭素数１乃至２２のアルコキシ基、又は−ＯＳｉＲ₁Ｒ₂Ｒ₃を表し、Ｒ₁、Ｒ₂、及びＲ₃はそれぞれ独立に、炭素数１乃至２２のアルキル基、炭素数６乃至１８のアリール基、炭素数１乃至２２のアルコキシ基、又は炭素数６乃至１８のアリールオキシ基を表す。） (Phthalocyanine compound)
The ink of the present invention is an inkjet ink containing a pigment as a color material. And the ink of this invention contains the compound represented by following General formula (1) as a pigment.
General formula (1):

(In the general formula (1), M represents a metal atom. Each A independently represents an aromatic ring or a heterocyclic ring. Each Z independently represents an aryloxy group having 6 to 18 carbon atoms or 1 carbon atom. Represents an alkoxy group having from 22 to 22 or —OSiR ₁ R ₂ R ₃ , and R ₁ , R ₂ , and R ₃ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, carbon Represents an alkoxy group having 1 to 22 carbon atoms or an aryloxy group having 6 to 18 carbon atoms.)

Hereinafter, each group in the general formula (1) will be described.
M in the general formula (1) represents a metal atom. Examples of metal atoms include group 14 element metal atoms such as copper, zinc, aluminum, silicon, germanium, and tin. Among these, a metal atom of a group 14 element such as silicon, germanium, or tin is preferable, and a silicon atom is particularly preferable from the viewpoint of color developability.

  Each A in the general formula (1) independently represents an aromatic ring or a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the heterocyclic ring include heteroaromatic rings such as pyridine ring and pyrazine ring; saturated heterocyclic rings such as pyrrolidine ring, piperidine ring, azepane ring and azocan ring; The aromatic ring or heterocyclic ring represented by A may have a substituent as long as it does not affect the color developability. For example, alkyl groups such as methyl, propyl, and tert-butyl groups; alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, and hexyloxy; nitro groups; halogen atoms such as chlorine atoms; sulfonic acid groups , A carboxy group and a salt thereof; and the like. A may contain a plurality of stereoisomers such as those in which the configuration of the substituent is different. For example, due to the synthesis method, a single steric structure may not be formed, and a plurality of stereoisomers may be included. These isomers have no significant effect on color development. From the viewpoint of color developability, A is preferably an unsubstituted benzene ring, an unsubstituted pyridine ring, or an unsubstituted pyrazine ring, and particularly preferably an unsubstituted benzene ring.

In the general formula (1), each Z independently represents an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or —OSiR ₁ R ₂ R ₃ . Z is an axial ligand of phthalocyanine.

  The aryloxy group constituting Z has 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms. For example, an aryloxy group in which an aromatic ring is directly connected to an oxygen atom such as a phenyloxy group or a naphthyloxy group; an aromatic ring such as a benzyloxy group, a tolylmethyloxy group, or a xylylmethyloxy group is oxygenated via a methylene group An aryloxy group bonded to an atom; and the like. Among them, an aryloxy group in which an aromatic ring is bonded to an oxygen atom via a methylene group is preferable, and a benzyloxy group is particularly preferable.

  The alkoxy group constituting Z has 1 to 22 carbon atoms, preferably 1 to 8 carbon atoms. The alkoxy group may be linear, branched, or a structure having a ring. The linear alkoxy group has 1 to 22 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, and an n-octoxy group. The branched alkoxy group has 1 to 22 carbon atoms, and examples thereof include an isopropyloxy group and a neopentyloxy group. The alkoxy group having a ring has 3 to 22 carbon atoms, and examples thereof include a cyclohexylmethyloxy group, a norbornylmethyloxy group, and an adamantylmethyloxy group.

R ₁ , R ₂ , and R ₃ of —OSiR ₁ R ₂ R ₃ constituting Z are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, or 1 to 22 carbon atoms. An alkoxy group or an aryloxy group having 6 to 18 carbon atoms is represented.

The alkyl group constituting R ₁ , R ₂ , and R ₃ has 1 to 22 carbon atoms, preferably 1 to 8 carbon atoms. The alkyl group may be linear, branched, or a ring-containing structure. The linear alkyl group has 1 to 22 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. The branched alkyl group has 3 to 22 carbon atoms, and examples thereof include an isopropyl group, an isobutyl group, and a t-butyl group. The alkyl group having a ring has 3 to 22 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group. All of R ₁ , R ₂ and R ₃ are preferably linear alkyl groups, and in particular, all of R ₁ , R ₂ and R ₃ are preferably methyl groups or n-propyl groups. .

The aryl group constituting R ₁ , R ₂ , and R ₃ has 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms. The aryl group may be either a group obtained by removing one hydrogen atom from an aromatic ring or a group obtained by removing one hydrogen atom from an alkyl group bonded to the aromatic ring. Examples thereof include a group obtained by removing one hydrogen atom from an aromatic ring, such as a phenyl group and a naphthyl group.

The alkoxy group constituting R ₁ , R ₂ and R ₃ has 1 to 22 carbon atoms, preferably 1 to 8 carbon atoms. The alkoxy group may be linear, branched, or a structure having a ring. For example, a linear alkoxy group having 1 to 8 carbon atoms such as a methoxy group and an ethoxy group can be given.

The aryloxy group constituting R ₁ , R ₂ , and R ₃ has 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms. Examples of the aryloxy group include an aryloxy group in which an aromatic ring such as a phenyloxy group or a naphthyloxy group is directly connected to an oxygen atom.

  In the general formula (1), Z is preferably a group having a monocyclic or polycyclic ring. These groups can further enhance the interaction with the urethane resin, and can further improve the ozone resistance of the image and the storage stability of the ink. Specifically, an aryloxy group having a monocyclic aromatic ring such as a benzyloxy group, a tolylmethyloxy group or a xylylmethyloxy group; an alkoxy having a monocyclic aliphatic ring such as a cyclohexylmethyloxy group More preferably an alkoxy group having a polycyclic alicyclic ring such as a norbornylmethyloxy group or an adamantylmethyloxy group;

  The group having a monocyclic or polycyclic ring is more preferably an aryloxy group directly connected to M or an alkoxy group directly connected to M. “Directly connected to M” means that an aryloxy group or an alkoxy group is bonded to M without passing through —OSi (siloxy group).

  As preferred specific examples of the compound represented by the general formula (1), compounds 1 to 36 are shown in Table 1. Of course, in the present invention, the compound represented by the general formula (1) and the compound satisfying the definition are not limited to the following compounds.

The average particle diameter (D ₅₀ ) of the compound represented by the general formula (1) is preferably 10 nm or more and 300 nm or less, and preferably 20 nm or more and 200 nm or less, from the viewpoint of color developability and glossiness of the image. Further preferred. The average particle size (D ₅₀ ) is a volume-based cumulative 50% particle size, and is a value measured using a dynamic scattering method. In the measurement, the pigment ink is diluted with pure water to an appropriate magnification. If necessary, auxiliary agents such as surfactants and pH adjusters are added.

  The content (% by mass) of the compound represented by the general formula (1) in the ink is preferably 0.5% by mass or more and 10.0% by mass or less based on the total mass of the ink. More preferably, it is 7 mass% or more and 5.0 mass% or less. Within the above range, it is possible to achieve a high level of basic performance as an ink, such as image coloring and glossiness, and ink ejection stability. Moreover, the compound represented by the general formula (1) may be used alone or in combination of two or more kinds in order to adjust the color tone of the ink. Moreover, you may use together a well-known pigment, dye, etc. other than the compound represented by the said General formula (1) as a coloring material.

(Method of verification)
The structure of the compound represented by the general formula (1) can be verified by the following method. First, dilute hydrochloric acid is added to the pigment ink to precipitate the deposited substance, and this is dried. The compound represented by the general formula (1) is obtained by charging this substance into a Soxhlet extractor and eluting the solvent and resin remaining in the substance using chloroform or the like. By dissolving this in deuterated dimethylformamide (deuterated DMF), measuring a nuclear magnetic resonance (NMR) spectrum, and analyzing the chemical shift, information on the structure of the phthalocyanine ring can be obtained. Moreover, the information regarding the structure of an axial ligand is obtained by analyzing the spectrum of pyrolysis gas chromatography / mass spectrometry (Py-GC / MS). Furthermore, information on the central metal can be obtained by analyzing the spectrum of inductively coupled plasma emission spectroscopy (ICP) and the energy of fluorescent X-rays.

(Urethane resin)
The ink of the present invention contains a urethane resin having at least a unit derived from a polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring and a unit derived from a polyol. The urethane resin can be synthesized from, for example, polyisocyanate, polyol, acid group-containing diol, and optionally added chain extender. The urethane resin may be used as a resin dispersant for dispersing the compound (pigment) represented by the general formula (1), or may be present in a free state in the ink without being used as a resin dispersant. It may be. In this invention, it is preferable to use the said urethane resin as a resin dispersing agent of the compound (pigment) represented by the said General formula (1).

[Unit derived from polyisocyanate having monocyclic aliphatic ring or monocyclic aromatic ring]
The urethane resin has a unit derived from a polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring. The kind of polyisocyanate used as the raw material of the unit derived from the polyisocyanate which has the said monocyclic aliphatic ring or monocyclic aromatic ring is not specifically limited. For example, polyisocyanates having a monocyclic aliphatic ring such as isophorone diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane; tolylene diisocyanate, xylylene diisocyanate, 1 , 3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and polyisocyanates having a monocyclic aromatic ring such as α, α, α, α-tetramethylxylylene diisocyanate; These polyisocyanates may be used alone or in combination of two or more. From the viewpoint of suppressing yellowing of the urethane resin, a polyisocyanate having a monocyclic alicyclic ring is preferable, and isophorone diisocyanate and 1,3-bis (isocyanatomethyl) cyclohexane are more preferable.

  The molar ratio of the unit derived from the polyisocyanate having a monocyclic aliphatic ring or monocyclic aromatic ring to the unit derived from all the polyisocyanates in the urethane resin is 0.85 times or more. Is preferred. By making the molar ratio 0.85 times or more, the gap formed on the surface of the compound represented by the general formula (1) due to the steric hindrance of the axial ligand and the interaction with the urethane resin Strengthen. For this reason, deterioration of the pigment due to ozone can be suppressed, and the ozone resistance of the image is improved. On the other hand, the theoretical upper limit of the molar ratio is 1.00 times. In this case, all the units derived from the polyisocyanate in the urethane resin are units derived from a polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring. Preferably, the molar ratio of the unit derived from the polyisocyanate having a monocyclic aliphatic ring or monocyclic aromatic ring to the unit derived from all the polyisocyanates in the urethane resin is 0.95 times or less. To do. By making it 0.95 times or less, the strength and flexibility of the film formed of urethane resin can be maintained in a well-balanced state, and it has good film properties and is easily adsorbed on the surface of pigment particles. The ozone resistance of the image is improved.

[Units derived from other polyisocyanates]
The urethane resin has a unit derived from a polyisocyanate other than a unit derived from a polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring (a unit derived from another polyisocyanate). Also good. The kind of polyisocyanate used as the raw material of the unit derived from other polyisocyanate is not specifically limited. For example, linear polyisocyanates such as tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methyl Branched polyisocyanates such as pentane-1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate; polyisocyanates having a polycyclic aliphatic ring such as 4,4′-dicyclohexylmethane diisocyanate; '-Diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dibenzyldiisocyanate, 1,5-naphthi Down diisocyanate, dialkyl diphenylmethane diisocyanate, polyisocyanates having polycyclic aromatic ring, such as tetraalkyl diphenyl methane diisocyanate; and the like.

  These polyisocyanates may be used alone or in combination of two or more. From the viewpoint of improving the ozone resistance of the image, these polyisocyanates have a molar ratio of the units derived from the other polyisocyanates to the units derived from all the polyisocyanates in the urethane resin is 0.15 times. Use within the range not exceeding.

[Unit derived from polyol]
The urethane resin has a unit derived from a polyol. The kind of polyol used as the raw material of the unit derived from the polyol is not particularly limited. For example, polyether polyols such as polyethylene glycol, poly (1,2-butylene glycol), poly (1,3-butylene glycol), polypropylene glycol, polytetramethylene glycol; polyethylene adipate glycol, polypropylene adipate glycol, polybutylene adipate glycol In addition to polyhexamethylene adipate glycol, etc., polymers obtained by condensation polymerization of glycols and dibasic acids (oxalic acid, succinic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, etc.) Polyester polyols; Polycarbonate polyols such as polybutylene carbonate diol, polyneopentyl carbonate diol, polyhexamethylene carbonate diol; These polyols may be used alone or in combination of two or more.

  The number average molecular weight of the unit derived from the polyol is 850 or more and 3,000 or less. When the number average molecular weight is 850 or more, an interval between urethane bonding groups or urea bonding groups in the urethane resin can be appropriately spaced, and aggregation of urethane resin chains due to excessive hydrogen bonding is suppressed. For this reason, the interaction between the compound represented by the general formula (1) and the urethane resin can be strengthened, and the ozone resistance of the image is improved. Further, the flexibility of the film formed of urethane resin is increased, and this also improves the ozone resistance of the image. Furthermore, by suppressing the aggregation of the urethane resin, there is an effect that the glossiness of the image and the storage stability of the ink are improved. On the other hand, by setting the number average molecular weight to 3,000 or less, the interval between the urethane bonding group or the urea bonding group is not excessively long, and the interaction with the compound represented by the general formula (1) is strengthened. Can do. Therefore, the ozone resistance of the image is improved. Also, the ozone resistance of the image is improved by the fact that the film made of urethane resin does not have excessive flexibility.

  The unit derived from the polyol is preferably a unit derived from a polyether polyol. In the unit derived from the polyether polyol, an excessively strong hydrogen bond is formed between the oxygen atom of the carbonyl of the ester or carbonate and the urethane bond group or the urea bond group, like the unit derived from the polyester polyol or the polycarbonate polyol. There is nothing to do. Accordingly, aggregation of the urethane resins is suppressed, and the glossiness of the image and the storage stability of the ink are improved.

[Acid group-containing diol unit]
The urethane resin may have a unit other than the unit derived from the polyisocyanate having the monocyclic aliphatic ring or monocyclic aromatic ring and the unit derived from the polyol. For example, in order to adjust the acid value of the urethane resin, it may have a unit derived from an acid group-containing diol.

  The raw material of the unit derived from the acid group-containing diol is not particularly limited. For example, diols containing a carboxy group as an acid group such as dimethylolpropionic acid and dimethylolbutanoic acid are preferred. These acid group-containing diols may be used alone or in combination of two or more. The acid group-containing diol may be in the form of a salt. The acid groups of the acid group-containing diol can exist as salt forms in an aqueous medium. Although the form of the salt is not particularly limited, a salt with an alkali metal such as Li, Na, K (alkali metal salt); a salt with ammonia (ammonium salt); dimethylamine, monoethanolamine, diethanolamine, triethanolamine, amine And salts with organic amines such as methylpropanol and N, N-dimethylethanolamine (organic amine salts); These salts may be used independently and may use 2 or more types together.

  The acid value of the urethane resin is preferably 50 mgKOH / g or more and 85 mgKOH / g or less. When the concentration is 50 mgKOH / g or more, the hydrophilicity is improved, so that the dispersion stability of the compound represented by the general formula (1) and the storage stability of the ink are also improved. Further, since the rapid aggregation of the urethane resin in the recording medium is suppressed, the glossiness of the image is also improved. On the other hand, by setting it to 85 mgKOH / g or less, the adsorptivity to the compound represented by the general formula (1) is improved, and the storage stability of the ink is also improved.

(Chain extender)
The urethane resin may have a unit derived from a chain extender. The kind of chain extender is not particularly limited. For example, diol chain extenders such as ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanedimethanol; ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, xylylenediamine, A diamine chain extender such as diphenylmethanediamine is preferred. These compounds may be used alone or in combination of two or more.

  The urea bond group content (mol%) in the urethane resin is preferably 0.10 times or less in terms of a molar ratio to the urethane bond group content (mol%). By setting the molar ratio to 0.10 times or less, excessive aggregation of the urethane resin due to the strong hydrogen bonding property of the urea bonding group is suppressed, and the glossiness of the image and the storage stability of the ink are improved. On the other hand, since the urethane resin may not have a urea bond, the theoretical lower limit of the molar ratio is 0.00 times. Preferably, the urea bond group content (mol%) in the urethane resin is 0.02 times or more in terms of a molar ratio to the urethane bond group content (mol%). By making it 0.02 times or more, the surface energy of ink droplets containing urethane resin is increased, and then the recorded ink droplets are wet spread on the surface of the image, and unevenness on the surface of the image is easily reduced. , The glossiness of the image is improved.

  The method for adjusting the molar ratio of the urethane bond group content (mol%) to the urea bond group content (mol%) in the urethane resin is not particularly limited. For example, the method of adjusting the quantity of the diamine type | system | group chain extender which occupies for the raw material of the said urethane resin is mentioned. That is, the urethane bond group is generated from a reaction between an isocyanate group, a polyol, an acid group-containing diol, and a diol chain extender, and a urea bond group is generated from a reaction between the isocyanate group and a diamine chain extender. Therefore, what is necessary is just to adjust the quantity of the diamine type | system | group chain extender which occupies for the raw material of the said urethane resin so that the number of moles of a urea bond group may become a desired ratio.

[Molecular weight of urethane resin]
The urethane resin preferably has a weight average molecular weight of 15,000 or more and 100,000 or less. When it is 15,000 or more, the adsorptivity to the compound represented by the general formula (1) is improved, and the storage stability of the ink is also improved. In addition, the urethane resin hardly penetrates into the recording medium, and the glossiness and ozone resistance of the image are improved. On the other hand, if it is 100,000 or less, the urethane resins are not easily entangled with each other, and the storage stability of the ink is improved. The weight average molecular weight of the urethane resin can be adjusted by the reactivity of the polyisocyanate used as a raw material, the chain length of the polyol, the reactivity and amount of the chain extender, or the reaction time.

[Ratio of pigment to urethane resin]
The content (mass%) of the urethane resin in the ink is a mass ratio with respect to the content (mass%) of the compound represented by the general formula (1), and is 0.25 times or more and 1.00 times or less. . When it is 0.25 times or more, the dispersion state of the compound represented by the general formula (1) tends to be stable, and the storage stability of the ink is also improved. Also, the glossiness of the image is improved. On the other hand, when the ratio is 1.00 times or less, the urethane resin is less likely to be entangled, thereby suppressing aggregation of the pigment and improving the storage stability of the ink. Further, by improving the balance between the urethane resin in the ink and the compound represented by the general formula (1), the surface of the pigment film of the recording medium is less likely to be uneven, and the glossiness of the image is improved.

  The content (% by mass) of the urethane resin in the ink is preferably 1.0% by mass or more and 15.0% by mass or less, based on the total mass of the ink, and is 2.0% by mass or more and 12.0% by mass. More preferably, it is% or less. Within the above range, it is possible to achieve a high level of basic performance as an ink, such as ozone resistance and glossiness of an image, and ink ejection stability.

(Method of verification)
The structure and physical properties of the urethane resin can be verified by the following method.

The composition of the urethane resin can be confirmed by analyzing a nuclear magnetic resonance (NMR) spectrum. First, the ink is centrifuged, and excess dilute hydrochloric acid is added to the supernatant to precipitate a urethane resin, and the dried solid is dissolved in deuterated dimethyl sulfoxide (heavy DMSO). To measure the NMR spectrum. From the chemical shift of the NMR signal, the types of polyisocyanate, polyol, acid group-containing diol, and chain extender that are raw materials can be confirmed. Moreover, these composition ratios can be calculated from the ratio of the integrated values of the respective NMR signals. Furthermore, by analyzing the spectrum of carbon nuclear magnetic resonance ( ¹³ C-NMR), the number of repeating units derived from polyol can be calculated, and the number average molecular weight can be calculated. Moreover, the kind of polyisocyanate, a polyol, and an acid group containing diol can also be confirmed by analyzing the spectrum of a pyrolysis gas chromatography / mass spectrometry (Py-GC / MS).

  The acid value of the urethane resin can be measured by dissolving the solid content obtained above in tetrahydrofuran and subjecting the solution to potentiometric titration with a potassium hydroxide-ethanol titrant.

  The weight average molecular weight of the urethane resin can be confirmed by dissolving the solid content obtained above in tetrahydrofuran and analyzing the solution by gel permeation chromatography (GPC) in terms of polystyrene.

The molar ratio of the urea bond group content to the urethane bond group content in the urethane resin was determined by dissolving the solid content obtained above in heavy DMSO and measuring the ¹³ C-NMR spectrum of the solution. This can be confirmed. That is, the ratio of the integral value of the peak of the urea bond group to the integral value of the peak of the urethane bond group may be calculated. Although a slight shift occurs depending on the measurement conditions, the peak of the urethane bonding group is observed in the vicinity of 155 ppm to 158 ppm, and the peak of the urea bonding group is observed in the vicinity of 158 ppm to 161 ppm.

(Other resins)
The ink of the present invention can contain a resin other than the urethane resin as long as the effects of the present invention are not impaired. Examples of such resins include (meth) acrylic acid resins, polyamide resins, polyester resins, polyvinyl alcohol resins, polyolefin resins, and the like. These resins may be used alone or in combination of two or more.

  A base may be added to the ink of the present invention. By the addition of the base, the resin can be stably present in the aqueous medium constituting the ink. Examples of such a base include inorganic bases such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonia; dimethylamine, monoethanolamine, diethanolamine, triethanolamine, aminemethylpropanol, N, N-dimethylethanol. Organic amines such as amines; and the like. These bases may be used alone or in combination of two or more. These bases may be added to the ink by using these bases as neutralizing agents for the acidic groups of the resin and preparing the ink using the neutralized resin.

(Aqueous medium)
In the ink of the present invention, an aqueous medium such as water or a mixed solvent of water and a water-soluble organic solvent can be used. The ink of the present invention is preferably an aqueous ink containing at least water as an aqueous medium. It is preferable to use deionized water (ion exchange water) as the water. The content (% by mass) of water in the ink is preferably 10.0% by mass or more and 90.0% by mass or less based on the total mass of the ink.

  The water-soluble organic solvent is not particularly limited as long as it is water-soluble, and it can be used for ink-jet inks such as alcohols, polyhydric alcohols, (poly) alkylene glycols, glycol ethers, nitrogen-containing polar solvents, sulfur-containing polar solvents, and the like. Any organic organic solvent can be used. One or more water-soluble organic solvents can be contained in the ink. The content (% by mass) of the water-soluble organic solvent in the ink is preferably 5.0% by mass or more and 90.0% by mass or less, based on the total mass of the ink, and 10.0% by mass or more and 50.0% by mass. More preferably, it is at most mass%.

(Other additives)
The ink of the present invention may contain a water-soluble organic compound that is solid at room temperature, if necessary, in addition to the components described above. Examples thereof include polyhydric alcohols such as trimethylolpropane and trimethylolethane; urea derivatives such as urea and ethyleneurea; Furthermore, the ink of the present invention may contain surfactants, pH adjusters, rust inhibitors, antiseptics, antifungal agents, antioxidants, antioxidants, evaporation accelerators, chelating agents, and others as necessary. Various additives such as these resins may be contained.

<Ink cartridge>
The ink cartridge of the present invention includes ink and an ink storage unit that stores the ink. The ink stored in the ink storage unit is the ink of the present invention described above. The ink cartridge has a structure in which the ink storage portion stores a negative pressure generation member storage chamber that stores a negative pressure generation member that is held in a state of being impregnated with negative pressure, and ink that is not impregnated by the negative pressure generation member. What is comprised with the ink storage chamber to accommodate is mentioned. In addition, there is no ink storage chamber as described above, and the entire amount of ink is held in a state impregnated with the negative pressure generating member, or the negative pressure generating member is not provided and the entire amount of ink is not impregnated with the negative pressure generating member. It is good also as an ink accommodating part of the structure accommodated in a state. Further, the ink cartridge may be configured to have an ink storage portion and a recording head.

<Inkjet recording method>
The inkjet recording method of the present invention is a method of recording an image on a recording medium by ejecting the ink of the present invention described above from an inkjet recording head. Examples of the method for ejecting ink include a method for imparting mechanical energy to the ink and a method for imparting thermal energy to the ink. In the present invention, a method for ejecting ink by applying thermal energy to the ink is used. It is particularly preferable to adopt it. Other than using the ink of the present invention, the steps of the ink jet recording method may be known.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited at all by the following Example, unless the summary is exceeded. In addition, what is described as “parts” and “%” with respect to the component amounts is based on mass unless otherwise specified.

<Synthesis of phthalocyanine compound>
A metal chloride was dropped into a liquid in which an isoindoline derivative was dispersed in 100.0 parts of quinoline under a nitrogen atmosphere while paying attention to heat generation. After completion of dropping, the liquid was heated to 230 ° C. and stirred for 5 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the precipitated solid was collected by vacuum filtration. The obtained solid was dispersed in N, N-dimethylformamide (DMF), and the dispersion was heated to 80 ° C. Impurities were removed by filtering this dispersion while hot to obtain dichlorometal phthalocyanine.

(Synthesis of phthalocyanine compounds whose axial ligand is an aryloxy group or an alkoxy group)
Under a nitrogen atmosphere, 60% sodium hydride (0.5 parts) was added little by little to a solution of 10.0 parts of toluene in which alcohol as an axial ligand was dissolved. Next, the dichlorometal phthalocyanine obtained above was added little by little, and then heated under reflux for 5 hours. After completion of the reaction, the reaction solution was diluted with 50.0 parts of n-hexane, and the precipitated solid was collected by filtration. The obtained solid was washed with ethanol and then washed with ion-exchanged water to obtain each phthalocyanine compound. The structure of each synthesized phthalocyanine compound was confirmed by ¹ H-NMR.

  Table 2 shows the types and amounts (parts) of isoindoline derivatives, metal chlorides, alcohols, and dichlorometal phthalocyanines used in the synthesis of each phthalocyanine compound.

(Synthesis of phthalocyanine compound whose axial ligand is OSiR ₁ R ₂ R ₃ )
Dichlorometal phthalocyanine and 1.5 parts of sodium hydroxide were added to a mixed solution of 150.0 parts of ion-exchanged water and 450.0 parts of pyridine under a nitrogen atmosphere, and then the temperature of the solution was raised to 100 ° C. And allowed to react for 1 hour under stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and the precipitated solid was filtered under reduced pressure and dried to synthesize dihydroxy metal phthalocyanine having a hydroxy group as an axial ligand.

After the dihydroxy metal phthalocyanine is dispersed in 650 parts of pyridine, the dispersion is heated to 120 ° C., and 550 parts of pyridine is removed by distillation to obtain a dispersion containing anhydrous dihydroxy metal phthalocyanine. It was. N, O-bis (trimethylsilyl) acetamide (5.0 parts) was added dropwise to the obtained dispersion, and then reacted for 2 hours while heating under reflux. After completion of the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered under reduced pressure and dried to obtain each phthalocyanine compound. The structure of each synthesized phthalocyanine compound was confirmed by ¹ H-NMR.

  Table 3 shows the types and amounts (parts) of dichloro metal phthalocyanine and dihydroxy metal phthalocyanine used for the synthesis of each phthalocyanine compound.

<Synthesis of urethane resin>
A four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a reflux tube is charged with the first polyisocyanate, the second polyisocyanate, a polyol, and 200.0 parts of methyl ethyl ketone, and the temperature is increased under a nitrogen gas atmosphere. The reaction was performed at 80 ° C. for 6 hours. The first polyisocyanate is a polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring, and the second polyisocyanate is a polyisocyanate other than the first polyisocyanate.

  Next, an acid group-containing diol, a chain extender, and 100.0 parts of methyl ethyl ketone were added to the reaction solution, and reacted at a temperature of 80 ° C. This reaction was performed until the residual ratio of the isocyanate group measured by FT-IR reached a desired residual ratio, and the weight average molecular weight of the urethane resin measured by gel permeation chromatography reached a desired value. After completion of the reaction, ion-exchanged water was added to the reaction solution cooled to a temperature of 40 ° C., and a potassium hydroxide aqueous solution was added while stirring at high speed with a homomixer to obtain a liquid containing a urethane resin. From the obtained liquid, methyl ethyl ketone was distilled off under reduced pressure by heating to obtain liquids containing urethane resins 1 to 31 each having a urethane resin (solid content) content of 20.0%.

Table 4 shows the types and amounts (parts) of the first polyisocyanate, the second polyisocyanate, the polyol, the acid group-containing diol, and the chain extender. Table 5 also shows the characteristics of the urethane resin. "Molar ratio of first polyisocyanate" is a molar ratio of units derived from polyisocyanate having a monocyclic aliphatic ring or monocyclic aromatic ring to units derived from all polyisocyanates in the urethane resin. And measured by ¹³ C-NMR. The acid value of the urethane resin was measured by potentiometric titration using a potassium hydroxide-ethanol titrant, and the weight average molecular weight was measured by gel permeation chromatography. "Molar ratio of urea bond / urethane bond", urethane resin, the content of the urea bond group (mole%), the mole ratio of the content of the urethane bond group (mole%), by ¹³ C-NMR It was measured.

Abbreviations shown in Table 4 are as follows. The number at the end of the polyol indicates its number average molecular weight.
IPDI: isophorone diisocyanate H6XDI: 1,3-bis (isocyanatemethyl) cyclohexane XDI: xylylene diisocyanate TMXDI: α, α, α, α-tetramethylxylylene diisocyanate HDI: hexamethylene diisocyanate H12MDI: 4,4′-dicyclohexylmethane Diisocyanate MDI: 4,4′-diphenylmethane diisocyanate PTMG: Polytetramethylene glycol PPG: Polypropylene glycol PEG: Polyethylene glycol PBA: Polybutylene adipate glycol PBC: Polybutylene carbonate diol DMPA: dimethylolpropionic acid DMBA: dimethylolbutanoic acid NPG: Neopentyl glycol EDA: Ethylenediamine IPDA: Iso Ronjiamin

<Preparation of pigment dispersion>
10.0 parts of the compound (pigment) represented by the general formula (1), a liquid containing urethane resin, and ion-exchanged water are placed in a glass container, and the filling rate of 0.3 mm-diameter zirconia beads is set to 50%. The pigment was dispersed using a disperser (trade name “DAS200-K”, manufactured by LAU). When dispersing, the dispersion is appropriately extracted, and the average particle size (D ₅₀ ) measured by a particle size measuring apparatus using a dynamic light scattering method (trade name “UPA-UT151”, manufactured by Nikkiso) is about 120 nm. The dispersion time was adjusted. Thereafter, centrifugal treatment was performed to remove coarse particles, and pressure filtration was performed with a microfilter having a pore size of 2.5 μm (manufactured by Fuji Film) to obtain pigment dispersions 1 to 46.

The average particle diameter (D ₅₀ ) of the pigment measured with the particle diameter measuring apparatus was in the range of 120 ± 3 nm. Table 6 shows the preparation conditions and characteristics of each pigment dispersion.

The contents of the abbreviations shown in Table 6 are as follows.
Copper phthalocyanine: C.I. I. Pigment Blue 15: 3 (trade name “Hostaperm Blue B2G”, manufactured by Clariant)
Acrylic: Styrene / 2-hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization ratio [mass ratio] 80.0: 11.6: 8.4, acid value 65 mgKOH / g, weight molecular weight 50,000) is hydroxylated An aqueous solution having a resin (solid content) content of 20.0%, neutralized with an aqueous potassium solution

<Preparation of ink>
(Examples 1 to 37, Comparative Examples 1 to 9)
The components shown below were mixed, sufficiently stirred and dispersed, and then subjected to pressure filtration with a microfilter having a pore size of 2.5 μm (manufactured by Fuji Film). Examples 1 to 37 and Comparative Examples 1 to 9 Each ink was prepared. The average particle size (D ₅₀ ) measured by a particle size measuring device using a dynamic light scattering method (trade name “UPA-UT151”, manufactured by Nikkiso) was in the range of 120 ± 3 nm.
-Pigment dispersion of the type shown in Table 6: 30.0 parts-Glycerin: 7.0 parts-2-Pyrrolidone: 5.0 parts-Polyethylene glycol (number average molecular weight 1,000): 3.0 parts-Nonionic properties Surfactant (trade name “Acetylenol E100”, manufactured by Kawaken Fine Chemical): 0.5 part ・ Preservative (trade name “Proxel GXL (S)”, manufactured by Arch Chemicals): 0.2 part ・ Ion-exchanged water: 54 .3 parts

(Comparative Example 10)
The components shown below were mixed, sufficiently stirred and dispersed, and then subjected to pressure filtration with a micro filter (manufactured by Fuji Film) having a pore size of 2.5 μm, whereby an ink of Comparative Example 10 was prepared.
-Phthalocyanine compound represented by the following formula (2): 3.0 parts-Glycerin: 7.0 parts-2-Pyrrolidone: 5.0 parts-Polyethylene glycol (number average molecular weight 1000): 3.0 parts-Nonionic properties Surfactant (trade name “Acetylenol E100”, manufactured by Kawaken Fine Chemical): 0.5 part ・ Preservative (trade name “Proxel GXL (S)”, manufactured by Arch Chemicals): 0.2 part ・ Ion-exchanged water: 81 .3 parts

Formula (2)

(Comparative Example 11)
The components shown below were mixed, sufficiently stirred and dispersed, and then subjected to pressure filtration with a micro filter (manufactured by Fuji Film) having a pore size of 2.5 μm, whereby an ink of Comparative Example 11 was prepared.
-Phthalocyanine compound represented by the following formula (3): 3.0 parts-Diethylene glycol: 10.0 parts-Nonionic surfactant (trade name "Triton X-100", manufactured by Kishida Chemical Co., Ltd .: 1.5 parts)
Buffering agent (trade name “Trizma Base”, manufactured by Sigma): 0.2 parts N, N-diethylethylenediamine: 3.0 parts Ion exchange water: 82.3 parts

Formula (3)

(Comparative Example 12)
The components shown below were mixed, sufficiently stirred and dispersed, and then subjected to pressure filtration with a microfilter (manufactured by Fuji Film) having a pore size of 2.5 μm, whereby an ink of Comparative Example 12 was prepared.
-Phthalocyanine compound represented by the following formula (4): 3.0 parts-Diethylene glycol: 10.0 parts-Nonionic surfactant (trade name "Triton X-100" Kishida Chemical: 1.5 parts-Buffering agent ( Product name "Trizma Base" (Sigma): 0.2 parts-Piperidine: 3.0 parts-Ion exchange water: 82.3 parts

Formula (4)

(Comparative Example 13)
Each component shown below was mixed and sufficiently stirred to mix to prepare an aqueous resin solution.
-Ion-exchanged water: 15.86 parts-Solid content of block copolymer of benzyl methacrylate / methacrylic acid = 57/43: 39.0% aqueous solution: 9.62 parts-Benzyl methacrylate / ethoxytriethylene glycol methacrylate-g-methoxypolyethylene glycol 44.2% aqueous solution of graft copolymer of methacrylate = 40 / 30-g-30: 8.48 parts

In the resin aqueous solution, C.I. I. Pigment Blue 15: 3 (trade name “Hostaperm Blue B2G”, manufactured by Clariant: 15.0 parts) was added in small portions. After the pigment was taken in, ion-exchanged water (38.24 parts) was added to form a mill base, which was circulated in a grinding media mill to disperse the pigment. Subsequently, in order to dilute to the final concentration, ion-exchanged water (11.51 parts) and a preservative (trade name “Proxel GXL”, manufactured by Arch Chemicals: 0.25 parts) were added to prepare a pigment dispersion. The pigment content in the pigment dispersion was 15.0%, the resin content was 7.5%, and the average particle size (D ₅₀ ) of the pigment was 92 nm.

  A dry flask free of alkali and acid was prepared with addition funnel, condenser, stirrer, and nitrogen gas piping network. A polyester polyol (trade name “Desmophen C200”, manufactured by Sumitomo Bayer Urethane: 439.90 parts), acetone (88.20 parts), and dibutyltin gyrarirate (0.06 parts) were added thereto. The contents were heated to 40 ° C. and mixed thoroughly. Next, isophorone diisocyanate (146.60 parts) was added to the mixture through the addition funnel over a period of 60 minutes under a temperature condition of 40 ° C., and the isophorone diisocyanate remaining in the addition funnel was added to the flask with acetone (21.80 parts). Washed away. The temperature in the flask was raised to 50 ° C., the reaction was performed at that temperature for 30 minutes, and then the reaction solution was cooled to 30 ° C.

  Further, APTES (60.60 parts), followed by DMPA (22.20 parts), followed by TEA (17.76 parts) were added to the reaction solution through an addition funnel, and finally, the inside of the addition funnel was charged with acetone ( 8.34 parts), and the washing liquid was also placed in the flask. Next, the temperature in the flask was raised again to 50 ° C., and the reaction was performed at that temperature for 60 minutes. Under conditions of 50 ° C., ion exchange water (1044.80 parts) was added through an addition funnel over 10 minutes, followed by 6.25% aqueous solution of EDA (120.00 parts) over 5 minutes, and finally added. The deposits in the funnel were washed into the flask with ion exchange water (107.53 parts). This mixture was reacted at 50 ° C. for 1 hour, and then the reaction solution was cooled to room temperature. Thereafter, acetone (118.34 parts) was distilled off under vacuum to obtain a urethane resin dispersion having a solid content of about 35.5%. APTES is aminopropyltriethoxysilane, DMPA is dimethylolpropionic acid, TEA is triethanolamine, and EDA is ethylenediamine.

The components shown below were mixed, sufficiently stirred and dispersed, and then pressure filtered through a microfilter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare an ink of Comparative Example 13.
-Pigment dispersion obtained above: 20.0 parts-Dispersion of urethane resin obtained above: 11.3 parts-1,2-hexanediol: 3.0 parts-2-pyrrolidone: 3.0 Parts ・ Triethylene glycol monobutyl ether: 5.0 parts ・ Glycerin: 17.7 parts ・ Ethylene glycol: 2.0 parts ・ Triethanolamine: 0.5 parts ・ Surfactant (trade name “BYK348”, Big Chemie Japan) Manufactured): 0.5 part Water: 37.0 parts

(Comparative Example 14)
Each component shown below was mixed to prepare a mixed solution.
Compound 7 in Table 1: 10.0 parts Methyl ethyl ketone: 20.0 parts Glycerin: 5.0 parts Styrene-acrylic acid copolymer (styrene / acrylic acid / 2-hydroxyethyl methacrylate = 80/5 / 15 copolymerization [mass] ratio, neutralized resin): 6.0 parts ・ Ion-exchanged water: 40.0 parts

  Zirconia beads (250.0 parts) having an average particle diameter of 0.5 mm were added to the mixed solution, and dispersion was performed for 4 hours using a media dispersing machine (trade name “System Zeta”, manufactured by Ashizawa). After the completion of dispersion, zirconia beads were filtered off to obtain a dispersion. After diluting this dispersion by adding water (40.0 parts), methyl ethyl ketone was distilled off under reduced pressure to obtain a colored fine particle dispersion.

Next, the components shown below were mixed, sufficiently stirred and dispersed, and then subjected to pressure filtration with a microfilter having a pore size of 2.5 μm (manufactured by Fuji Film) to prepare an ink of Comparative Example 14.
The above-mentioned colored fine particle dispersion: an amount in which the content of the compound 7 in Table 1 is 3.0% based on the total mass of the ink. Ethylene glycol: 15.0 parts Glycerin: 15.0 parts Triethylene glycol mono Butyl ether: 3.0 parts Nonionic surfactant (trade name “Surfinol 465”, manufactured by Air Products Japan): 0.3 parts Ion-exchanged water: Amount of 100.0 parts of total ink

(Comparative Example 15)
Each component shown below was mixed to prepare a mixed solution.
Compound 8 in Table 1: 10.0 parts Methyl ethyl ketone: 20.0 parts Glycerin: 5.0 parts Styrene-acrylic acid copolymer (styrene / acrylic acid / 2-hydroxyethyl methacrylate = 80/5 / 15 copolymerized (mass) ratio neutralized resin): 6.0 parts Ion-exchanged water: 40.0 parts

  Zirconia beads (250.0 parts) having an average particle diameter of 0.5 mm were added to the mixed solution, and dispersion was performed for 4 hours using a media dispersing machine (trade name “System Zeta”, manufactured by Ashizawa). After the completion of dispersion, zirconia beads were filtered off to obtain a dispersion. After diluting this dispersion by adding water (40.0 parts), methyl ethyl ketone was distilled off under reduced pressure to obtain a colored fine particle dispersion.

Next, the components shown below were mixed, sufficiently stirred and dispersed, and then subjected to pressure filtration with a micro filter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare an ink of Comparative Example 15.
The above-mentioned colored fine particle dispersion: an amount in which the content of the compound 8 in Table 1 is 3.0% based on the total mass of the ink. Ethylene glycol: 15.0 parts Glycerin: 15.0 parts Triethylene glycol mono Butyl ether: 3.0 parts ・ Nonionic surfactant (trade name “Surfinol 465”, manufactured by Air Products Japan): 0.3 part ・ Ion-exchanged water: Amount of 100.0 parts of total ink

(Comparative Example 16)
Each component shown below was mixed to prepare a mixed solution.
Compound 4 in Table 1: 10.0 parts Methyl ethyl ketone: 20.0 parts Styrene / acrylic acid copolymer (styrene / acrylic acid / 2-hydroxyethyl methacrylate = 80/5/15 copolymer [mass] Ratio and resin neutralized with 1.1 molar equivalents of potassium hydroxide): 5.0 parts ・ Ion-exchanged water: 35.0 parts

Add zirconia beads (diameter 0.05 mm, density 6.03 × 10 ⁻⁶ g / m) (250.0 parts) to the mixed solution, and add a media disperser (trade name “Starmill Minizea”, manufactured by Ashizawa). Used for dispersion for 3 hours. After completion of the dispersion, zirconia beads were filtered off to obtain a dispersion, and then methyl ethyl ketone was removed by distillation under reduced pressure to obtain a colored fine particle dispersion having a median particle diameter of 150 nm.

Next, the components shown below were mixed, sufficiently stirred and dispersed, and then subjected to pressure filtration with a microfilter (manufactured by Fuji Film) having a pore size of 2.5 μm, whereby an ink of Comparative Example 16 was prepared.
-Colored fine particle dispersion: 15.0 parts-Glycerin: 7.0 parts-Diethylene glycol: 5.0 parts-Trimethylolpropane: 7.0 parts-Acetylenol EH: 0.5 parts-Ion exchange water: 65. 5 copies

<Evaluation>
The following evaluation was performed using each of the inks obtained above. In the present invention, according to the evaluation criteria of each item, A and B are acceptable levels, and C is an unacceptable level. Table 7 shows the evaluation results.

(Preparation of recorded material)
Each ink obtained above was filled in an ink cartridge and mounted on an ink jet recording apparatus (trade name “PIXUS Pro 9500 Mark II”, manufactured by Canon Inc.) that discharges ink by the action of thermal energy. In this ink jet recording apparatus, an image recorded under a condition in which 8 ink droplets having a mass per droplet of 3.5 nanograms are applied to a unit area of 1/600 inch × 1/600 inch, a recording duty is 100. %. Then, on the recording medium (trade name “Canon Photo Paper / Glossy Pro [Platinum Grade] PT101”, manufactured by Canon), each recording duty is 16 gradations of 3 cm × 3 cm in 10% increments from 10% to 160%. A pattern including a solid image was recorded in the default mode to obtain a recorded matter. The obtained recorded matter was allowed to stand at room temperature for 1 day and dried, and then evaluated for the presence or absence of the bronzing phenomenon, ozone resistance, and glossiness. The optical density was measured using a spectrophotometer (trade name “Spectrolino”, manufactured by Gretag Macbeth) under the conditions of light source: D50 and field of view: 2 °.

(Bronze phenomenon)
A solid image having an optical density closest to 1.0 was selected from the 16-tone solid images of the recorded matter obtained above. The solid image was visually observed in an indoor environment having a daylight white fluorescent lamp (color temperature of about 5000 K) as illumination, and the presence or absence of bronzing was evaluated according to the following evaluation criteria.
A: Almost no bronzing phenomenon was confirmed.
B: A slight bronze phenomenon was confirmed.
C: The bronze phenomenon was remarkably confirmed.

(Ozone resistance)
A solid image having an optical density closest to 1.0 was selected from the 16-tone solid images of the recorded matter obtained above. Thereafter, the recorded material was placed in an ozone test apparatus (trade name “Ozone Weather Meter”, manufactured by Suga Test Instruments Co., Ltd.) and subjected to ozone for 40 hours under the conditions of a bath temperature of 23 ° C., a relative humidity of 50% and an ozone gas concentration of 5 ppm. Exposed. Thereafter, the recorded matter was taken out from the ozone test apparatus and left at room temperature for one day, and then the optical density was measured again. The residual ratio of optical density (%) = (optical density after exposure / optical density before exposure) × 100 was calculated, and ozone resistance was evaluated according to the evaluation criteria shown below.
A: The residual ratio of the optical density was 90% or more.
B: The residual ratio of the optical density was 85% or more and less than 90%.
C: The residual ratio of the optical density was less than 85%.

(Glossy)
Of the 16 gradation solid images of the recorded matter obtained above, a solid image having an optical density closest to 1.0 is selected, and a haze value is measured using a micro haze meter (manufactured by BYK Gardner). The glossiness was evaluated according to the evaluation criteria. Evaluation of glossiness can be judged by image clarity, which is one of the important characteristics for expressing glossiness. A high haze value means low image clarity and low glossiness. Low means high image clarity and high gloss.
A: The haze value was 10 or more and 15 or less.
B: The haze value was more than 15 and 20 or less.
C: The haze value was more than 20.

(Storage stability)
30 g of each of the inks obtained above was put in a sealed container, sealed, and placed in an environment at a temperature of 60 ° C. for 30 days. The average particle size (D ₅₀ ) of the ink before and after storage was measured with a particle size measuring device (trade name “UPA-UT151”, manufactured by Nikkiso Co., Ltd.), and the increase rate (%) of the average particle size was calculated from the following formula. The storage stability was calculated according to the following evaluation criteria.
Average particle diameter increase rate (%) = ((average particle diameter after storage−average particle diameter before storage) / average particle diameter before storage) × 100
A: The increase rate of the average particle diameter was 5% or less.
B: The increase rate of the average particle diameter was more than 5% and 10% or less.
C: The increase rate of the average particle diameter was more than 10%.

Claims (8)

An inkjet ink containing a pigment and a urethane resin,
The pigment contains a compound represented by the following general formula (1):
The urethane resin has at least a unit derived from a polyisocyanate having a monocyclic aliphatic ring or a monocyclic aromatic ring, and a unit derived from a polyol;
The molar ratio of the unit derived from the polyisocyanate having a monocyclic aliphatic ring or monocyclic aromatic ring to the unit derived from all the polyisocyanates in the urethane resin is 0.85 times or more,
The number average molecular weight of the unit derived from the polyol is 850 or more and 3,000 or less,
The acid value of the urethane resin is 50 mgKOH / g or more and 85 mgKOH / g or less,
The content (mass%) of the urethane resin is a mass ratio with respect to the content (mass%) of the compound represented by the general formula (1), and is 0.25 times or more and 1.00 times or less. And ink.
General formula (1):

(In the general formula (1), M represents a metal atom. Each A independently represents an aromatic ring or a heterocyclic ring. Each Z independently represents an aryloxy group having 6 to 18 carbon atoms or 1 carbon atom. Represents an alkoxy group having from 22 to 22 or —OSiR ₁ R ₂ R ₃ , and R ₁ , R ₂ , and R ₃ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, carbon Represents an alkoxy group having 1 to 22 carbon atoms or an aryloxy group having 6 to 18 carbon atoms.)   The ink according to claim 1, wherein Z in the general formula (1) is a group having a monocyclic or polycyclic ring.   The ink according to claim 2, wherein the group having a monocyclic or polycyclic ring is an aryloxy group directly connected to M or an alkoxy group directly connected to M.   The ink according to any one of claims 1 to 3, wherein the urethane resin has a weight average molecular weight of 15,000 or more and 100,000 or less.   The ink according to any one of claims 1 to 4, wherein the unit derived from the polyol is a unit derived from a polyether polyol.   The content (mol%) of the urea bonding group in the urethane resin is 0.10 times or less in terms of a molar ratio with respect to the content (mol%) of the urethane bonding group. The ink described in 1. An ink cartridge comprising ink and an ink containing portion for containing the ink,
The ink cartridge according to claim 1, wherein the ink is an ink according to claim 1. An inkjet recording method for recording an image on a recording medium by discharging ink from an inkjet recording head,
An ink jet recording method, wherein the ink is the ink according to any one of claims 1 to 6.