JP6083263B2 - Ink jet recording ink, ink cartridge, recording method, recording apparatus, recorded matter - Google Patents

Description

  The present invention relates to an inkjet recording ink.

  In recent years, as an image forming method, since the process is simple and full color can be easily obtained as compared with other recording methods, there is an advantage that a high-resolution image can be obtained even with an apparatus having a simple configuration. The method has become widespread. The ink jet recording method is a method in which a small amount of ink is ejected by an ink jet recording apparatus and is deposited on a recording medium such as paper, and the application has been expanded to personal and industrial printers and printing.

  Ink jet recording apparatuses mainly use water-based ink using a water-soluble dye as a colorant, but the dye ink has a disadvantage that it is inferior in weather resistance and water resistance. Therefore, in recent years, research on pigment inks using pigments instead of water-soluble dyes has been advanced. However, the pigment ink is still inferior in color development, ink ejection stability, and storage stability to the dye ink. In addition, with the improvement of image quality improvement technology for OA printers, image density equivalent to that of dye ink is required for both pigment ink and plain paper as a recording medium. However, when plain paper is used as a recording medium, the pigment ink has a problem that the pigment density on the paper surface is lowered by penetrating into the paper and the image density is lowered. In order to increase the drying speed of the ink adhering to the recording medium for high-speed printing, a means is taken to accelerate drying by adding a penetrant to the ink and allowing water to penetrate into the recording medium. Not only that, the penetrability of the pigment into the recording medium is increased, and the image density is further lowered.

  Various methods have been proposed for improving the image density. For example, Patent Document 1 discloses a water-based ink for inkjet recording, which contains carbon black or an organic pigment, a polymer, a basic substance, and water as essential components. At this time, the ink comprises a copolymer obtained by polymerizing (meth) acrylic acid and another copolymerizable monoethylenically unsaturated monomer as essential components, and a phosphate group-containing monoethylenically unsaturated monomer. It contains a copolymer obtained by polymerizing a monomer and other copolymerizable monoethylenically unsaturated monomers as essential components.

  Patent Document 2 discloses an ink used for recording on paper containing a water-soluble polyvalent metal salt. At this time, the ink includes (a) a pigment, (b) a functional group having no surface activity, a molecular weight of 150 or more and 10,000 or less, and having phosphoric acid as a basic skeleton in the molecular structure. And a phosphoric acid-based functional group and a phosphonic acid as a basic skeleton having a phosphorus content ((P content / molecular weight) x 100) of 1.4 or more. It contains at least one compound having a functional group selected from functional groups, and (b) the content (% by mass) of the compound is 1.5% by mass or more and 10.0% by mass based on the total mass of the ink. It is characterized by the following.

  Regarding the storage stability of the pigment ink, that is, the dispersion stability of the pigment, Patent Document 3 discloses an inkjet ink using a copolymer composed of a specific monomer unit as a dispersant. At this time, the copolymer used as a dispersant in this ink has a mass ratio (A: B) between the methacrylic polymer unit (A) and the aromatic vinyl monomer unit (B) of A: B = 5 to 95. : 95-5.

Patent Document 1 exemplifies the monomer represented by the general formula (4) of the present invention as the phosphoric acid group-containing monoethylenically unsaturated monomer. The general formula (4), the structural formula (5), and the structural formula There is no exemplification of a copolymer using the monomer (6) together, and the effect on improving pigment dispersion stability is not described.
On the other hand, Patent Document 2 also does not exemplify a copolymer using both monomers of the general formula (4), structural formula (5), and structural formula (6) in the present invention. It does not describe the effect of improving the image density and improving the pigment dispersion stability in plain paper having a low content.
Also, Patent Document 3 does not exemplify a copolymer using the monomers represented by the general formula (4), structural formula (5), and structural formula (6) in the present invention, and describes the effect on the image density improvement effect. It has not been.

An object of the present invention is to solve the above-described problems and achieve the following objects.
That is, the present invention provides an ink for ink jet recording in which a high image density is obtained on plain paper, the back-through of the image is reduced, and the pigment dispersion and the dispersion stability of the pigment as the ink are good. Objective.

As a result of intensive studies, the present inventors have used a copolymer having a phosphate group and a specific structural unit as a component of the ink for ink-jet recording, so that the ink for ink-jet recording aggregates on the surface of plain paper, It has been found that the pigment remains on the surface of the paper, so that a high image density on plain paper can be obtained, the back-through of the image is reduced, and the dispersion of the pigment as a pigment dispersion and ink is stabilized. The present invention has been reached.
That is, the above-mentioned problems are solved by the following “Inkjet recording ink”, “Inkjet recording ink container such as ink cartridge”, “Recording method”, “Recording apparatus” and “Recorded matter” "Is solved.
(1) “In the inkjet recording ink having at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphate group, the copolymer containing the phosphate group is represented by the general formula (1)” An ink for ink jet recording, comprising at least a unit, a structural unit represented by Structural Formula (2), and a structural unit represented by Structural Formula (3).

(R1 in the general formula (1) represents a hydrogen atom or a methyl group. M represents a hydrogen atom, an alkali metal, or an organic ammonium ion. N and m each represents an integer of 0 to 6 (provided that n , M must not be 0 at the same time)).

(2) As described in (1) above, wherein the viscosity of the 10% by weight solid content aqueous solution or aqueous dispersion of the copolymer containing phosphate groups is 4.0 to 30.0 mPa · s. Ink for inkjet recording. "
(3) “Pigment, water, the structural unit represented by the general formula (1), the structural unit represented by the structural formula (2), and the structural unit represented by the structural formula (3) at least The ink for inkjet recording according to (1) or (2), comprising at least a water dispersion of a pigment composed of a copolymer having a water-soluble solvent.
(4) The above-mentioned (1), wherein the weight ratio of the pigment to the copolymer in the aqueous dispersion of the pigment containing the copolymer is pigment / copolymer = 100/10 to 100/100. The ink for inkjet recording according to any one of (1) to (3).
(5) The inkjet recording according to any one of (1) to (4), wherein M in the general formula (1) constituting the copolymer is a hydrogen atom, a potassium atom, or a sodium atom. For ink. "
(6) “Ink for inkjet recording according to any one of (1) to (5) above, wherein glycerin is included as the water-soluble solvent.”
(7) An ink storage container having an ink storage section for storing ink, wherein the ink stored in the ink storage section is the ink described in (1). . "
(8) “An ink jet recording apparatus that records information or an image on a recording medium using an ink jet head, wherein the ink is the ink described in (1) above”. "
(9) “A method for manufacturing a recorded matter including a step of performing recording on a recording medium by ejecting ink from an ink jet head, wherein the ink is the ink according to (1)”. Manufacturing method. "
(10) “Recorded matter in which information or images are recorded on a recording medium using ink, wherein the ink is the ink according to (1)”.
In addition, the “ink-jet recording ink” of the present invention includes the following more specific ink.
(11) “In the inkjet recording ink having at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphate group, the copolymer containing a phosphate group is represented by the general formula (4). An ink for inkjet recording, which is synthesized using at least a monomer, a monomer represented by Structural Formula (5), and a monomer represented by Structural Formula (6) as starting materials.

(R1 in the general formula (4) represents a hydrogen atom or a methyl group. N and m each represents an integer of 0 to 6 (provided that the values of n and m must not be 0 at the same time)).

(12) “The content of the structural unit of the general formula (1) in the copolymer containing a phosphate group or the polymerization rate of the monomer represented by the general formula (4) is 10 wt% to 60 wt%. Ink for ink-jet recording according to any one of (1) to (6) or item (11) above,
(13) The above-mentioned (1) to (6), wherein n and m in the general formula (1) or the general formula (4) constituting the copolymer are m = 1 and n = 1. Or the inkjet recording ink according to any one of (11) to (12).
(14) “The ratio of hydrogen atoms to the total number of M in the general formula (1) or the monomer of the general formula (4) constituting the copolymer is 0% to 40%. The ink for inkjet recording according to any one of (1) to (6) or any one of (11) to (13).

In the inkjet recording ink of the present invention, the copolymer containing a phosphate group is represented by the structural unit represented by the general formula (1), the structural unit represented by the structural formula (2), and the structural formula ( It is characterized by having at least the structural unit represented by 3).
The phosphate group in the general formula (1) is hydrophilic, but has a characteristic of reacting with ions such as calcium ion, magnesium ion, and aluminum ion to make it hydrophobic. Therefore, ink for inkjet recording using a copolymer containing a phosphoric acid group as a pigment dispersant dissolves from the recording medium when the pigment dispersant adsorbed on the pigment is used in a recording medium containing a water-soluble polyvalent metal salt. The pigment agglomerates by reacting with the polyvalent metal ions and making it hydrophobic.
As a result, the penetration of the pigment into the paper can be suppressed, a high image density can be obtained, and the back-through where the image can be seen through from the back side of the paper surface can be reduced.
However, in PPC paper (Plane Paper Copy paper, that is, plain paper or high-quality paper) that does not contain a water-soluble polyvalent metal salt, the amount of metal ions eluted from the recording medium is small, and the image density due to aggregation of pigments The improvement effect was insufficient.

  As a method for solving the above problems, a method for increasing the ratio of the structural unit portion of the general formula (1) (or the monomer of the general formula (4)) of the copolymer containing a phosphate group or the hydrophobicity of the pigment dispersant. A method of increasing the proportion of structural units and enhancing the adsorption of the dispersant and the pigment can be considered. However, if the constituent ratio of the general formula (1) is increased, the interaction between phosphoric acid groups becomes stronger, or the pigment dispersibility is lowered or the viscosity increases when the pigment dispersion and the water-soluble solvent are mixed. It has been found. It has also been found that increasing the proportion of hydrophobic structural units decreases the dispersion stability of the pigment in the pigment dispersion and the ink and increases the viscosity.

  In the present invention, in addition to the structural unit of the general formula (1) (or the monomer of the general formula (4), the same applies hereinafter), the structural formula (2) (or the monomer of the general formula (5), the same applies hereinafter), By combining the structural unit of the structural formula (3) (or the monomer of the general formula (6), the same applies hereinafter), the following effects can be obtained, and the content of the water-soluble polyvalent metal salt is low or only slightly soluble. A high image density can be obtained even on plain paper not included. Further, the dispersion stability of the pigment in the pigment dispersion and the ink could be ensured. The effect of each structure of said structural formula (2) and said structural formula (3) is demonstrated in detail below.

That is, (i) The introduction of the structural portion of the structural formula (2) increased the affinity of the copolymer for water, and increased the viscosity of the pigment dispersion and ink. Therefore, the introduction amount of the structural part of the general formula (1) was increased, and the reactivity with metal ions could be increased.
(Ii) By introducing the structural portion of the structural formula (2), the affinity of the copolymer to the water-soluble solvent is increased, the initial viscosity when the ink is made can be kept low, and the ink is stored. Stability could also be improved.
(Iii) By introducing the structural portion of the structural formula (3), the adsorptive power of the copolymer to the pigment was improved, and the pigment was easily aggregated when the copolymer reacted with metal ions. As a result, the image density was improved.

  An ink jet recording apparatus having an ink ejecting means for recording an image on a recording medium by ejecting the ink for ink jet recording of the present invention from a recording head, and applying ink through the ink ejecting means to eject ink from the recording head. If an image is recorded on a recording medium, high density image formation can be realized. In addition, if the ink for ink jet recording of the present invention is accommodated in a container to form an ink cartridge, it can be easily attached to and detached from the ink cartridge loading portion provided in the ink jet recording apparatus, and stable ink supply can be performed for a long time. Become. The ink recorded matter of the present invention has high image quality and excellent stability over time, and can be suitably used for various applications as materials on which various prints or images are recorded.

It is a schematic plan view for explaining an example of the ink cartridge of the present invention. FIG. 2 is a schematic plan view including a case (exterior) of the ink cartridge of the present invention shown in FIG. 1. 1 is a perspective view showing an example of a serial type ink jet recording apparatus of the present invention. FIG. 4 is a partially enlarged sectional view of the ink jet recording apparatus shown in FIG. 3. FIG. 4 is another partially enlarged sectional view of the ink jet recording apparatus shown in FIG. 3.

(Copolymer containing phosphate group)
The copolymer containing a phosphate group used in the present invention is represented by the structural unit represented by the general formula (1), the structural unit represented by the structural formula (2), and the structural formula (3). It is obtained by copolymerizing at least the monomers of the general formula (4), the structural formula (5), and the structural formula (6).

For example, a solvent in a flask equipped with a stirrer, a thermometer, a nitrogen introduction tube, a monomer of the general formula (4), a monomer of the structural formula (5), and a monomer of the structural formula (6) are used as a polymerization initiator. It can be obtained by reacting at a temperature of about 50 to 150 ° C. under reflux of nitrogen gas in the presence.
Details are described in the Examples.

The viscosity of the aqueous solution or aqueous dispersion of the copolymer containing a phosphate group in the present invention can be adjusted by changing the molecular weight, and the monomer concentration, the polymerization initiator amount, the polymerization temperature, and the polymerization time during polymerization can be adjusted. Change it.
You may add another monomer component to the copolymer containing the said phosphate group.

  Examples of the monomer represented by the general formula include monomers represented by the following structural formulas (4-1) to (4-5).

As the synthesis method, various known synthesis methods such as solution polymerization, suspension polymerization, bulk polymerization, emulsion polymerization and the like can be used. However, since the polymerization operation and the adjustment of the molecular weight are easy, a radical polymerization initiator is used. The method used is preferred.
As the radical polymerization initiator, those generally used can be used, and specifically, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyesters, cyano series Azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobis (2,2′-isovaleronitrile), non-cyano dimethyl-2,2′-azobisisobutyrate, and the like. . Organic peroxides and azo compounds that can easily control the molecular weight and have a low decomposition temperature are preferable, and azo compounds are more preferable. As for the usage-amount of a polymerization initiator, 1-10 mass% is preferable with respect to the total mass of a polymerizable monomer.

  Moreover, in order to adjust the molecular weight of the copolymer containing a phosphate group, mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, dodecyl mercaptan, 1-dodecanethiol, thioglycerol, etc. An appropriate amount of chain transfer agent may be added to the polymerization system.

A preferable polymerization temperature is 50 to 150 ° C., and a preferable polymerization time is 3 to 48 hours.
The monomer of the structural formula (4-1) represents 2-acryloyl ethyl acid phosphoate. 2-Acroyloxyethyl acid phosphoate is commercially available from Kyoeisha Chemical Industry Co., Ltd. under the product name “Light Acrylate P-1A”.
The monomer represented by the structural formula (4-2) represents 2-methacryloxyethyl acid phosphoate. 2-Methacryloxyethyl acid phosphoate is commercially available under the product name “Light Ester P-1M” from Kyoeisha Chemical Industry Co., Ltd. and “Phosmer M” from Unichemical Corporation.
The monomer of the structural formula (4-3) represents acid phosphoxypolyoxyethylene glycol methacrylate.
The monomer of the structural formula (4-4) represents acid phosphoxypolyoxypropylene glycol methacrylate.
The monomer of the structural formula (4-5) represents acid phosphoxypoly (oxyethyleneoxypropylene) glycol methacrylate. These monomers of structural formulas (4-3) to (4-5) are commercially available under the product names of Unichemical Co., Ltd. Phosmer PE and Phosmer PP.
That is, the monomers of (Formula 4-3) to (Formula 4-4) are commercially available under the product names of Unichemical Co., Ltd. Phosmer PE and Phosmer PP.
The monomer of (Formula 4-5) is a conventionally known compound described in JP-T-2003-506536, and in this case, for convenience, it will be referred to as phosmer PEP.

Moreover, it is preferable that the phosphate group in the copolymer containing the phosphate group of the present invention is ionized by neutralizing a part or all of it with a base.
Bases used for neutralization include alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium, mono, di or trimethylamine, mono, di or triethylamine, monoethanolamine, diethanolamine, triethanolamine and methylethanol. Amine, methyldiethanolamine, dimethylethanolamine, choline, aminoethanepropanediol, monopropanolamine, dipropanolamine, tripropanolamine, isopropanolamine, trishydroxymethylaminomethane, aminoethylpropanediol, tetramethylammonium, tetraethylammonium, tetra Organic amines such as butylammonium, monophorin, N-methylmonoformin, N-methyl-2pyrrolidone, 2- Organic amines such as cyclic amines, such as pyrrolidone and the like.

  The monomer of the structural formula (5) represents glyceryl acrylate. Glycerol acrylate is commercially available from NOF Corporation under the product name “Blemmer GLM”.

The constituent ratio of the structural unit of the general formula (1) of the copolymer containing a phosphate group used in the present invention is preferably 5% by weight to 80% by weight, and preferably 10% by weight to 60% by weight with respect to the copolymer weight. % Is more preferable. When it is 10% by weight or more, the effect of improving the image density is clearly shown, and when it is 60% by weight or less, the storage stability of the pigment dispersion and ink is remarkably improved.
In addition, the structural ratio of the structural unit (2) is preferably 10% by mass to 35% by mass with respect to the mass of the copolymer. When it is 10% by mass or more, the viscosity of the dispersion and the ink becomes low, and when it is 35% by mass or less, the effect of improving the image density is clearly exhibited.
Furthermore, 10 mass%-60 mass% are preferable with respect to the copolymer mass, and, as for the structural ratio of structural formula (3) structural unit, 50 mass%-60 mass% are more preferable. When it is 50% by mass or more, the storage stability of the dispersion and the ink is improved, and when it is 60% by mass or less, the effect of improving the image density is clearly exhibited.

  The viscosity of the 10% by weight solid content aqueous solution or 10% by weight solid content aqueous dispersion of the copolymer containing phosphate groups is preferably in the range of 3.0 to 35.0 mPa · s, preferably 4.0 to 30. More preferably, it is in the range of 0.0 mPa · s. When it is 4.0 mPa · s or more, the reactivity between the metal ions eluted from the paper and the pigment dispersant is further improved, and the effect of improving the image density becomes remarkable. When it is 30.0 mPa · s or less, the dispersion stability of the pigment is further improved, and the storage stability of the pigment dispersion is further improved.

  The copolymer containing phosphoric acid groups used in the present invention is preferably 0.5% by weight to 10.0% by weight as a solid content with respect to the total weight of the ink, and preferably 1.0% by weight to 5.0%. More preferably, it is% by weight. The addition of 0.5% by weight clearly shows the effect of improving the image density, and by making it 10.0% by weight or less, it is possible to keep the viscosity within a range suitable for ejecting ink from the head.

If the copolymer containing a phosphate group used in the present invention is used as a colorant dispersant, the image density on plain paper can be further improved. Further, the storage stability of a solvent-rich ink in which the water-soluble solvent exceeds 20% is further improved.
When used as a dispersant, it is 1 to 100% by weight, preferably 5 to 80% by weight, based on 100% by weight of the color material. Within this range, the most suitable colorant particle size is obtained, and the image density, dispersibility, and storage stability are in a good range. Moreover, you may use together the dispersing agent described later with a copolymer in the range which does not impair the said effect.

(water)
As water used in the present invention, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used.
The water content is preferably 20 to 60% by weight based on the total amount of ink.

(Water-soluble solvent)
The water-soluble solvent used in the present invention is necessary for improving the ejection stability by providing a moisturizing effect in the ink composition. The content is preferably 10 to 50% by weight based on the total amount of ink.
When the content is less than 10% by weight, the ink easily evaporates, and thickened ink may be clogged due to evaporation of the ink in the ink supply system in the ink jet recording apparatus. When the content is more than 50% by weight, clogging of thickened ink is less likely to occur in the ink jet recording apparatus, but it is necessary to reduce the amount of solids such as pigments and resins in order to make the ink have a desired viscosity. In this case, the image density of the recorded matter may be lowered.

Examples of the water-soluble solvent used in the present invention include, but are not limited to, the following. For example, ethylene glycol, diethylene glycol, 1,3-butanediol, 3-methyl-1,3-butyl glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerin 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,2,4-butanetriol, 1,2,3 -Polyhydric alcohols such as butanetriol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetra Polyhydric alcohol alkyl ethers such as tylene glycol monomethyl ether and propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, nitrogen-containing heterocyclic compounds such as ε-caprolactam, γ-butyrolactone, amides such as formamide, N-methylformamide, N, N-dimethylformamide , Amines such as monoethanolamine, diethanolamine, triethylamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol, propylene carbonate, ethylene carbonate, etc. That.
These water-soluble solvents can be used alone or in combination of two or more.
Among these, the inclusion of 1,3-butanediol, diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol, triethylene glycol and / or glycerin is excellent in preventing discharge failure due to moisture evaporation. Effect.

The following penetrants are also included as the water-soluble solvent used in the present invention.
The penetrant preferably contains either a polyol compound having 8 to 11 carbon atoms or a glycol ether compound having 8 to 11 carbon atoms. The penetrant may be referred to as a “non-wetting agent medium”. These non-wetting agent penetrants preferably have a solubility of between 0.2 and 5.0% by weight in water at 25 ° C.
Among these, 2-ethyl-1,3-hexanediol [solubility: 4.2% by weight (25 ° C.)], 2,2,4-trimethyl-1,3-pentanediol [solubility: 2.0% by weight] (25 ° C.)] is particularly preferred.
As other polyol compounds, as aliphatic diols, for example, 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1, 3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene- 1,2-diol and the like can be mentioned.

  Other penetrants that can be used in combination are not particularly limited as long as they can be dissolved in the ink and adjusted to the desired physical properties, and can be appropriately selected according to the purpose. For example, diethylene glycol monophenyl ether, ethylene Glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, alkyl and aryl ethers of polyhydric alcohols such as tetraethylene glycol chlorophenyl ether, lower alcohols such as ethanol, etc. Is mentioned.

  The content of the penetrant in the ink-jet ink is preferably 0.1 to 4.0% by weight. When the content is less than 0.1% by weight, a fast-drying property cannot be obtained and a blurred image may be obtained. When the content exceeds 4.0% by weight, the dispersion stability of the pigment is impaired, and the nozzle Clogging may easily occur, permeability to a recording medium (recording medium) may become unnecessarily high, and image density may be lowered or showthrough may occur.

(Pigment)
The content of the pigment used in the present invention in the recording ink is preferably 0.1% by weight or more and 20.0% by weight or less. The volume average particle diameter (D50) of the pigment is preferably 150 nm or less.
Here, the volume average particle diameter (D50) of the pigment is measured by a dynamic light scattering method using Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.
There is no restriction | limiting in particular as these pigments, According to the objective, it can select suitably, For example, any of an inorganic pigment and an organic pigment may be sufficient. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, metal powder, and carbon black. Among these, carbon black is preferable. In addition, as said carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, and a thermal method, is mentioned, for example.

  Examples of the organic pigment include azo pigments, azomethine pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more preferable.

  Examples of the azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, rhodamine B lake pigments, and the like. It is done. Examples of the dye chelates include basic dye chelates and acidic dye chelates.

Examples of black materials include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), titanium oxide, and the like. And organic pigments such as aniline black (CI Pigment Black 1).
The carbon black is a carbon black produced by a furnace method or a channel method, a primary particle size is 15 nm to 40 nm, a specific surface area by a BET method is 50 m2 / g to 300 m2 / g, and a DBP oil absorption is 40 ml / 100 g. Those having ˜150 ml / 100 g, volatile content of 0.5% to 10% and pH value of 2-9 are preferred.
A commercially available product can be used as the carbon black. Examples of commercially available products include No. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Columbia); Regal400R, 330R, 660R, Mogu L, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot); Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, and 4 (all manufactured by Degussa).

  The pigment that can be used for the yellow ink for color is not particularly limited and can be appropriately selected according to the purpose. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 180, and the like.

  The pigment that can be used in the magenta ink for color is not particularly limited and may be appropriately selected depending on the intended purpose. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, pigment violet 19, and the like.

  The pigment that can be used for the cyan ink for the color is not particularly limited and may be appropriately selected according to the purpose. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.

In addition, the pigment contained in each ink used in the present invention may be newly produced for the present invention.
By using Pigment Yellow 74 as the yellow pigment, Pigment Red 122, Pigment Bio Red 19 as the magenta pigment, and Pigment Blue 15: 3 as the cyan pigment, an ink with excellent color tone and light fastness and balanced can be obtained. Can be obtained.

Furthermore, the pigment used in the present invention can be a grafted or encapsulated product coated with a surfactant such as a dispersant or a resin, but the compound of the present invention is used as a dispersant. Is more preferable.
Moreover, you may use together the pigment mentioned above in the range which does not impair an effect.

(Other ingredients)
There is no restriction | limiting in particular as another component used for the composition of the ink for inkjet recording of this invention, It can select suitably as needed. Examples of other components include a dispersant, a pH adjuster, a water-dispersible resin, an antiseptic / antifungal agent, a chelating reagent, a rust inhibitor, an antioxidant, an ultraviolet absorber, an oxygen absorber, and a light stabilizer. Is mentioned.

(Dispersant)
As the dispersant, the copolymer containing a phosphate group of the present invention is preferable, but various surfactants and polymers such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant are used. Also included are types of dispersants. These may be used alone or in combination of two or more.

  Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurate, polyoxyalkyl ether sulfates. Salt, polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, naphthalenesulfonate formalin condensate, alkyl type phosphate ester, alkylallylsulfone hydrochloride, diethyl Examples include sulfosuccinate, diethylhexyl sulfosuccinate, and dioctyl sulfosuccinate.

  Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

  Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline. Derivatives and the like.

Examples of nonionic surfactants include the following.
Ether-based interfaces such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyallylalkyl alkyl ether Active agent;
Polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate Ester surfactants such as
2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol Examples thereof include acetylene glycol surfactants.

(PH adjuster)
The pH adjuster is not particularly limited as long as the pH can be adjusted to 8.5 to 11 and preferably 9 to 11 without adversely affecting the ink jet ink to be prepared. For example, alcohol amines, hydroxides of alkali metal elements, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like can be used. When the pH is less than 8.5 or more than 11, the amount of the ink jet head or ink supply unit that melts out is large, and problems such as ink deterioration, leakage, and ejection failure may occur. When it is less than 8.5, the ink pH may decrease during storage of the ink, and the polymer fine particles may aggregate due to an increase in the particle diameter.

  The pH can be measured by, for example, a pH meter HM-30R (manufactured by TOA-DKK).

  Examples of the alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the ammonium hydroxide include ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and the like. Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

(Water dispersible resin)
The water-dispersible resin has excellent film-forming properties (image formability), high water repellency, high water resistance, and high weather resistance, and has high water resistance and high image density (high color development). Useful for.
Specific examples of the water-dispersible resin include condensation-type synthetic resins, addition-type synthetic resins, natural polymer compounds, and the like.
Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, and fluorine-based resin. Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like.
Examples of the natural polymer compound include celluloses, rosins, and natural rubber.
Among these, polyurethane resin fine particles, acrylic-silicone resin fine particles, and fluorine-based resin fine particles are particularly preferable.

The volume average particle diameter (D50) of the water-dispersible resin is related to the viscosity of the dispersion, and for the same composition, the viscosity at the same solid content increases as the particle diameter decreases. The volume average particle diameter (D50) of the water-dispersible resin is preferably 50 nm or more so that the ink does not have an excessively high viscosity. Further, when the particle size is several tens of μm, it becomes larger than the nozzle opening of the ink jet head and cannot be used. If particles having a large particle diameter are present in the ink even though they are smaller than the nozzle opening, the ejection stability is deteriorated. Therefore, the volume average particle diameter (D50) is more preferably 200 nm or less in order not to disturb the ink ejection stability.
Here, the volume average particle diameter (D50) of the water-dispersible resin is measured by a dynamic light scattering method using Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.

The water-dispersible resin has a function of fixing the water-dispersed pigment on the paper surface, and is preferably formed into a film at room temperature to improve the fixability of the color material. Therefore, it is preferable that the minimum film-forming temperature (MFT) of the water-dispersible resin is 30 ° C. or less.
Further, when the glass transition temperature of the water-dispersible resin is -40 ° C. or lower, the resin film becomes more viscous and the printed matter is tacky. Therefore, the water-dispersible resin has a glass transition temperature of −30 ° C. or higher. It is preferable.
The content of the water-dispersible resin in the ink-jet ink is preferably 1 to 15% by weight, more preferably 2 to 7% by weight in terms of solid content.

(Antiseptic and antifungal agent)
Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol, and the like.

(Chelating reagent)
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.

(Rust inhibitor)
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

(Antioxidant)
Examples of the antioxidant include phenolic antioxidants (including hindered phenolic antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.

(UV absorber)
Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.

(Inkjet ink manufacturing method)
The ink-jet ink of this embodiment is obtained by dispersing or dissolving water, a water-soluble solvent, a pigment, a copolymer containing a phosphate group, and other components in an aqueous medium as required, and further if necessary. Produced by stirring and mixing.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, and the like. be able to.

There is no restriction | limiting in particular as a physical property of the inkjet ink of this invention, According to the objective, it can select suitably, For example, it is preferable that viscosity, surface tension, etc. are the following ranges.
The viscosity of the inkjet ink at 25 ° C. is preferably 3 mPa · s to 20 mPa · s. By setting the ink viscosity to 3 mPa · s or more, the effect of improving the printing density and the character quality can be obtained. On the other hand, by suppressing the ink viscosity to 20 mPa · s or less, it is possible to ensure the discharge performance.
The viscosity can be measured at 25 ° C. using a viscometer (RL-550, manufactured by Toki Sangyo Co., Ltd.).

  The surface tension of the inkjet ink is preferably 40 mN / m or less at 25 ° C. When the surface tension exceeds 40 mN / m, leveling of the ink on the recording medium is difficult to occur and the drying time may be prolonged.

(Ink container such as ink cartridge)
The ink container such as the ink cartridge of the present invention contains the ink for ink jet recording of the present invention, and can also constitute other members appropriately selected as necessary.
There is no restriction | limiting in particular in the shape, a structure, a magnitude | size, and a material as said container, According to the objective, it can select suitably. Preferred examples include those having at least an ink bag formed of an aluminum laminate film, a resin film, or the like.

One embodiment of the ink cartridge of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic plan view for explaining an example of the ink cartridge of the present invention. FIG. 2 is a schematic plan view including a case (exterior) of the ink cartridge of FIG.
As shown in FIG. 1, the ink cartridge 200 is filled into the ink bag 241 from the ink inlet 242 and exhausted, and then the ink inlet 242 is closed by fusion. In use, the needle of the apparatus main body is pierced into the ink discharge port 243 made of a rubber member and supplied to the apparatus.
The ink bag 241 is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 2, the ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably mounted on various ink jet recording apparatuses.

(Inkjet recording apparatus and inkjet recording method)
The ink jet recording apparatus of the present invention includes at least ink flying means, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.
The inkjet recording method of the present invention includes at least an ink flying process, and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.

The ink jet recording method of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.
The ink flying step is a step of forming an image by applying a stimulus to the ink jet ink of the present invention and causing the ink jet ink to fly.
The ink flying means is means for forming an image by applying a stimulus to the ink-jet ink of the present invention and causing the ink-jet ink to fly. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.
The stimulus can be generated, for example, by the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, heat and pressure are preferable. Examples of the stimulus generating means include a superheater, a pressurizer, a piezoelectric element, a vibration generator, an ultrasonic oscillator, and a light. Specifically, a piezoelectric actuator such as a piezoelectric element such as a piezoelectric element, a thermal actuator that uses a phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a shape that uses a metal phase change due to a temperature change Memory alloy actuators, electrostatic actuators using electrostatic force, and the like can be mentioned.

  There is no particular limitation on the mode of the ink flying, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, the thermal energy corresponding to the recording signal is output to the ink in the recording head. For example, using a thermal head or the like, generating bubbles in the ink by the thermal energy, and ejecting and ejecting the ink as droplets from the nozzle holes of the recording head by the pressure of the bubbles. It is done. Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting the ink as droplets from the nozzle holes of the recording head.

  The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

Here, one aspect of carrying out the ink jet recording method of the present invention by the ink jet recording apparatus of the present invention will be described with reference to the drawings.
FIG. 3 is a perspective view showing an example of the serial type ink jet recording apparatus of the present invention.
The ink jet recording apparatus shown in FIG. 3 stocks an apparatus main body 101, a paper feed tray 102 for loading paper loaded on the apparatus main body 101, and paper on which an image is recorded (formed) mounted on the apparatus main body 101. A paper discharge tray 103 and an ink cartridge loading unit 104 protruding forward from the front surface 112 and lower than the upper cover 111 are provided at one end of the front surface 112 of the apparatus main body 101. On the upper surface of the ink cartridge loading unit 104, an operation unit 105 such as operation keys and a display is arranged. The ink cartridge loading unit 104 has a front cover 115 that can be opened and closed for attaching and detaching the ink cartridge 200.

As shown in FIGS. 4 and 5 (partially enlarged sectional view of the ink jet recording apparatus shown in FIG. 3), a guide which is a guide member horizontally mounted on left and right side plates (not shown) is provided in the apparatus main body 101. The carriage 133 is slidably held in the main scanning direction by the rod 131 and the stay 132, and is moved and scanned in the direction of the arrow as shown in FIG. 5 by the main scanning motor.
The carriage 133 is provided with a recording head 134 composed of four ink jet recording heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.

  As the ink jet recording head constituting the recording head 134, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a metal phase due to temperature change, etc. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink can be used. In addition, the carriage 133 is equipped with a sub tank 135 for each color for supplying ink of each color to the recording head 134. The sub tank 135 is supplied with the ink from the ink cartridge 200 of the present invention loaded in the ink cartridge loading unit 104 via an ink supply tube (not shown) and is replenished.

On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking unit (pressure plate) 141 of the paper feeding tray 102, a half-moon roller (feeding) that separates and feeds the paper 142 from the paper stacking unit 141 one by one. A separation pad 144 made of a material having a large coefficient of friction is provided facing the paper roller 143) and the paper feed roller 143, and the separation pad 144 is urged toward the paper feed roller 143 side.
As a transport unit for transporting the paper 142 fed from the paper feed unit below the recording head 134, a transport belt 151 for transporting the paper 142 by electrostatic adsorption and a guide 145 from the paper feed unit. The counter roller 152 for transporting the paper 142 fed via the transport belt 151 with the transport belt 151 and the paper 142 fed substantially vertically upward are changed by approximately 90 ° to follow the transport belt 151. For this purpose, a conveyance guide 153 and a tip pressure roller 155 urged toward the conveyance belt 151 by a pressing member 154 are provided.

  In addition, a charging roller 156 that is a charging unit for charging the surface of the conveyance belt 151 is provided. The conveyance belt 151 is an endless belt, is stretched between the conveyance roller 157 and the tension roller 158, and can circulate in the belt conveyance direction. The transport belt 151 includes, for example, a surface layer serving as a sheet adsorbing surface formed of a resin material having a thickness of about 40 μm that is not subjected to resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), and the surface layer. It has a back layer (medium resistance layer, earth layer) that is made of the same material and has resistance controlled by carbon. On the back side of the conveyance belt 151, a guide member 161 is arranged corresponding to a printing area by the recording head 134.

  Note that, as a paper discharge unit for discharging the paper 142 recorded by the recording head 134, a separation claw 171 for separating the paper 142 from the conveyance belt 151, a paper discharge roller 172, and a paper discharge roller 173 are provided. The paper discharge tray 103 is disposed below the paper discharge roller 172.

A double-sided paper feeding unit 181 is detachably mounted on the back surface of the apparatus main body 101.
The double-sided paper feeding unit 181 takes in the paper 142 returned by the reverse rotation of the transport belt 151, reverses it, and feeds it again between the counter roller 152 and the transport belt 151. A manual paper feed unit 182 is provided on the upper surface of the duplex paper feed unit 181.
In this ink jet recording apparatus, the paper 142 is separated and fed one by one from the paper feed unit, and the paper 142 fed substantially vertically upward is guided by the guide 145 and between the transport belt 151 and the counter roller 152. It is sandwiched and conveyed. Further, the leading end is guided by the conveying guide 153 and pressed against the conveying belt 151 by the leading end pressure roller 155, and the conveying direction is changed by approximately 90 °. At this time, the conveyance roller 157 is charged by the charging roller 156, and the sheet 142 is electrostatically attracted to the conveyance belt 151 and conveyed. Therefore, by driving the recording head 134 according to the image signal while moving the carriage 133, ink droplets are ejected onto the stopped paper 142 to record one line, and after the paper 142 is conveyed by a predetermined amount, Record the next line.

  Upon receiving a recording end signal or a signal that the trailing edge of the sheet 142 has reached the recording area, the recording operation is terminated and the sheet 142 is discharged onto the discharge tray 103. When the ink remaining amount near end in the sub tank 135 is detected, a required amount of ink is supplied from the ink cartridge 200 to the sub tank 135.

  In this ink jet recording apparatus, when the ink in the ink cartridge 200 of the present invention is used up, the casing of the ink cartridge 200 can be disassembled and only the ink bag inside can be replaced. Further, the ink cartridge 200 can supply ink stably even when the ink cartridge 200 is installed vertically and has a front loading configuration. Therefore, the ink cartridge 200 is installed even when the upper portion of the apparatus main body 101 is closed, for example, when stored in a rack, or when an object is placed on the upper surface of the apparatus main body 101. Can be easily exchanged.

In addition, although it demonstrated in the example applied to the serial type (shuttle type) inkjet recording device which a carriage scans, it can apply similarly to the line type inkjet recording device provided with the line type head.
The ink jet recording apparatus of the present invention can be applied to various types of recording by the ink jet recording method, and is particularly preferably applied to, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like. Can do.

(Ink record)
The ink recorded matter recorded by the ink jet recording method of the present invention is the ink recorded matter of the present invention. That is, the ink recorded matter of the present invention has an image recorded with the ink for ink jet recording of the present invention on a recording medium (recording medium).
The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include plain paper, coated paper for printing, glossy paper, special paper, cloth, film, and OHP sheet. It is done. These may be used individually by 1 type and may use 2 or more types together.
Among these, at least one of plain paper and coated paper for printing is preferable. The plain paper is advantageous in that it is inexpensive. The coated paper for printing is advantageous in that it provides a smooth glossy image at a relatively low cost as compared with glossy paper. However, although the drying property is poor and it is generally difficult to use for inkjet, the drying property is improved by the ink of the present invention.
The ink recorded matter of the present invention has high image quality, no bleeding, excellent stability with time, and can be suitably used for various purposes as materials on which various prints or images are recorded.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples. “Part” represents “part by mass” unless otherwise specified. “%” Represents “% by mass” unless otherwise specified.

(Measurement of copolymer viscosity)
The viscosity of the 10% by weight aqueous solution or 10% by weight aqueous dispersion of the synthesized copolymer was measured using a rotational viscometer (TV-22 viscometer / cone plate type, manufactured by Toki Sangyo Co., Ltd.). Specific operations are shown below. 1.1 mL of the copolymer was collected and placed in a viscometer sample cup. After the sample cup was attached to the viscometer body and allowed to stand for 1 minute, the viscometer rotor was rotated and the value after 1 minute was read.

<Synthesis of copolymer>
[Synthesis Example 1]
Phosmer M (2-methacryloxyethyl acid phosphoate); 6.0 g, GLM (glycerin methacrylate); 2.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 15 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 1 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 1 was 15.0 mPa · s.

[Synthesis Example 2]
Phosmer M (2-methacryloxyethyl acid phosphoate); 3.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, 1.33 g of azobisisobutyronitrile at 75 ° C. was added, and a polymerization reaction was carried out for 3 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. Thus, a copolymer 2 in which the phosphate group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 2 was 3.8 mPa · s.

[Synthesis Example 3]
Phosmer M (2-methacryloxyethyl acid phosphoate); 1.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 3 in which the phosphate group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 3 was 4.1 mPa · s.

[Synthesis Example 4]
Phosmer M (2-methacryloxyethyl acid phosphoate); 3.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 4 in which the phosphate group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 4 was 4.5 mPa · s.

[Synthesis Example 5]
Phosmer M (2-methacryloxyethyl acid phosphoate); 11.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 2.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, 1.33 g of azobisisobutyronitrile at 75 ° C. was added, and a polymerization reaction was carried out for 3 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 5 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 5 was 3.7 mPa · s.

[Synthesis Example 6]
Phosmer M (2-methacryloxyethyl acid phosphoate); 13.0 g, GLM (glycerin methacrylate); 4.0 g, ViN (vinyl naphthalene); 3.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 6 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 6 was 4.1 mPa · s.

[Synthesis Example 7]
Phosmer M (2-methacryloxyethyl acid phosphoate); 11.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 2.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 7 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 7 was 4.2 mPa · s.

[Synthesis Example 8]
Phosmer M (2-methacryloxyethyl acid phosphoate); 11.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 2.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 48 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 8 in which the phosphate group was neutralized 100% was synthesized. The viscosity of the 10% by mass aqueous solution of the obtained copolymer was 31.1 mPa · s.

[Synthesis Example 9]
Phosmer M (2-methacryloxyethyl acid phosphoate); 13.0 g, GLM (glycerin methacrylate); 4.0 g, ViN (vinyl naphthalene); 3.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 24 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 9 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 9 was 29.0 mPa · s.

[Synthesis Example 10]
Phosmer M (2-methacryloxyethyl acid phosphoate); 11.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 2.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 24 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 10 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 10 was 28.2 mPa · s.

[Synthesis Example 12]
Phosmer M (2-methacryloxyethyl acid phosphoate); 3.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 48 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. Thus, the copolymer 11 in which the phosphate group was neutralized 100% was synthesized. The viscosity of the 10 mass% aqueous solution of the obtained copolymer 11 was 30.5 mPa · s.

[Synthesis Example 12]
Phosmer M (2-methacryloxyethyl acid phosphoate); 1.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 24 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 12 in which the phosphate group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 12 was 28.9 mPa · s.

[Synthesis Example 13]
Phosmer M (2-methacryloxyethyl acid phosphoate); 3.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 24 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 13 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 13 was 29.5 mPa · s.

[Synthesis Example 14]
Phosmer M (2-methacryloxyethyl acid phosphoate); 3.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, sodium hydroxide was added so that 100% acid neutralization was achieved, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 14 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 14 was 4.5 mPa · s.

[Synthesis Example 15]
Phosmer M (2-methacryloxyethyl acid phosphoate); 3.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, lithium hydroxide was added to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 15 having 100% neutralized phosphate groups was synthesized. The viscosity of the 10% by mass aqueous solution of the obtained copolymer 15 was 4.2 mPa · s.

[Synthesis Example 16]
Phosmer M (2-methacryloxyethyl acid phosphoate); 1.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, dimethylethanolamine was added to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 16 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 16 was 4.3 mPa · s.

[Synthesis Example 17]
Phosmer M (2-methacryloxyethyl acid phosphoate); 1.0 g, GLM (glycerin methacrylate); 7.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, 1.33 g of azobisisobutyronitrile at 75 ° C. was added, and a polymerization reaction was carried out for 3 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 17 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 17 was 2.9 mPa · s.

[Synthesis Example 18]
Phosmer M (2-methacryloxyethyl acid phosphoate); 13.0 g, GLM (glycerin methacrylate); 4.0 g, ViN (vinyl naphthalene); 3.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 48 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 18 in which the phosphate group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 18 was 30.4 mPa · s.

[Synthesis Example 19]
Light acrylate P-1A (2-acryloyloxyethyl acid phosphoate); 6.0 g, GLM (glycerin methacrylate); 2.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; The mixture was stirred in a flask to obtain a uniform solution.
After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 12 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 19 in which the phosphate group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 19 was 14.1 mPa · s.

[Synthesis Example 20]
Phosmer PE (acid phosphoxypolyoxyethylene glycol methacrylate (structural formula (4-3)); 6.0 g, GLM (glycerin methacrylate); 2.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g Was stirred in a four-necked flask to obtain a homogeneous solution, and nitrogen was blown into the solution for 30 minutes, and then azobisisobutyronitrile (1.33 g) was added at 50 ° C. for 12 hours to cause a polymerization reaction. A viscous product obtained by removing the solvent from the polymerization solution using an evaporator was added to acetone to collect a solid, and potassium hydroxide was used so as to achieve 100% acid neutralization while diluting the obtained copolymer with water. The dialysis membrane was purified for 3 days, and the concentration was adjusted with water so that the solid concentration was 10% by weight. The neutralized copolymer 20 was synthesized. The viscosity of the 10 wt% aqueous solution of the resulting copolymer 20 had a 18.8mPa · s.

[Synthesis Example 21]
Phosmer PP (acid phosphoxypolyoxypropylene glycol methacrylate (structural formula (4-4)); 6.0 g, GLM (glycerin methacrylate); 2.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g Was put into a four-necked flask and stirred to obtain a homogeneous solution, and nitrogen was blown into the solution for 30 minutes, and then 1.33 g of azobisisobutyronitrile was added at 60 ° C. to carry out a polymerization reaction for 15 hours. A viscous product obtained by removing the solvent from the polymerization solution using an evaporator was added to acetone to collect a solid, and potassium hydroxide was used so as to achieve 100% acid neutralization while diluting the obtained copolymer with water. The dialysis membrane was purified for 3 days, and the concentration was adjusted with water so that the solid concentration was 10% by weight. The neutralized copolymer 21 was synthesized%. The viscosity of the 10 wt% aqueous solution of the resulting copolymer 21 had a 20.3 MPa · s.

[Synthesis Example 22]
Phosmer PEP (acid phosphoxypoly (oxyethyleneoxypropylene) glycol methacrylate (structural formula (4-5)); 6.0 g, GLM (glycerin methacrylate); 2.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol 113.0 g was placed in a four-necked flask and stirred to obtain a homogeneous solution, and nitrogen was blown into this solution for 30 minutes, and then azobisisobutyronitrile was added at 60 ° C .; A viscous product obtained by removing the solvent from the polymerization solution by an evaporator was added to acetone to recover a solid, and 100% acid neutralization was achieved while diluting the obtained copolymer with water. Potassium hydroxide was added, and the dialysis membrane was purified for 3 days, and the concentration was adjusted with water so that the solid concentration was 10% by weight. Te, the viscosity of the 10 wt% aqueous solution of the copolymer 22 phosphate group is neutralized 100% was synthesized. The resulting copolymer 22 had a 15.1 MPa · s.

[Synthesis Example 23]
Phosmer M (2-methacryloxyethyl acid phosphoate); 6.0 g, GLM (glycerin methacrylate); 2.0 g, ViN (vinyl naphthalene); 12.0 g, ethanol; 113.0 g were placed in a four-necked flask. To a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 60 ° C., and a polymerization reaction was carried out for 15 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 50% acid neutralization, and the dialysis membrane was purified for 3 days. Further, the solid content concentration was 10% by weight. The concentration was adjusted with water. In this way, a copolymer 23 having 50% neutralized phosphate groups was synthesized. The viscosity of the 10% by mass aqueous solution of the obtained copolymer 23 was 24.5 mPa · s.

[Synthesis Example 24 (Comparative Synthesis Example 1)]
Phosmer M (2-methacryloxyethyl acid phosphoate); 20.0 g, ethanol; 113.0 g were placed in a four-necked flask and stirred to obtain a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 5 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 24 in which the phosphate group was neutralized 100% was synthesized. The viscosity of the 10% by mass aqueous solution of the obtained copolymer 24 was 5.1 mPa · s.

[Synthesis Example 25 (Comparative Synthesis Example 29)]
GLM (glycerin methacrylate); 6.0 g, ViN (vinyl naphthalene); 14.0 g, ethanol; 113.0 g were placed in a four-necked flask and stirred to obtain a uniform solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 65 ° C., and a polymerization reaction was carried out for 10 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 25 in which the phosphate group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 25 was 10.1 mPa · s.

[Synthesis Example 26 (Comparative Synthesis Example 3)]
MAA (methacrylic acid); 6.0 g, ViN (vinyl naphthalene); 14.0 g, ethanol; 113.0 g were placed in a four-necked flask and stirred to obtain a homogeneous solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 60 ° C., and a polymerization reaction was carried out for 15 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. The resulting copolymer was purified with a dialysis membrane for 3 days while diluting with water, and the concentration was adjusted with water so that the solid concentration was 10% by weight. In this way, a copolymer 26 was synthesized. The viscosity of the 10% by mass aqueous solution of the obtained copolymer 26 was 19.5 mPa · s.

[Synthesis Example 27 (Comparative Synthesis Example 4)]
Phosmer M (2-methacryloxyethyl acid phosphoate); 6.0 g, MAA (methacrylic acid); 14.0 g, ethanol; 113.0 g were placed in a four-necked flask and stirred to obtain a uniform solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 50 ° C., and a polymerization reaction was carried out for 12 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 27 having 100% neutralized phosphate groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 27 was 20.0 mPa · s.

[Synthesis Example 28 (Comparative Synthesis Example 5)]
Styrene; 10.0 g, GLM (glycerin methacrylate); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask and stirred to obtain a uniform solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 60 ° C., and a polymerization reaction was carried out for 10 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. Further, the concentration was adjusted with water so that the solid concentration was 10% by weight.
In this way, a copolymer 28 was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer 28 was 14.1 mPa · s.

[Synthesis Example 29 (Comparative Synthesis Example 6)]
Styrene; 10.0 g, MAA (methacrylic acid); 10.0 g, ethanol; 113.0 g were placed in a four-necked flask and stirred to obtain a uniform solution. After nitrogen was blown into this solution for 30 minutes, azobisisobutyronitrile; 1.33 g was added at 60 ° C., and a polymerization reaction was carried out for 15 hours. A viscous product obtained by removing the solvent from the polymerization solution with an evaporator was added to acetone to collect a solid. While diluting the obtained copolymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and dialysis membrane purification was performed for 3 days. Further, the solid content concentration was adjusted to 10% by weight. The concentration was adjusted with water. In this way, a copolymer 29 in which acid groups were neutralized 100% was synthesized.
The viscosity of a 10% by mass aqueous solution of the obtained copolymer 29 was 21.0 mPa · s.
Each of these synthesis examples and the properties of the resulting copolymer are shown in the following table.

<Preparation of pigment dispersion>
[Pigment Dispersion Preparation Example 1: Preparation of Black Pigment Dispersion 1]
The black pigment dispersion 1 was prepared as follows.
A mixture of the following formulation (1) was premixed to prepare a mixed slurry (a). This was circulated and dispersed in a disk type media mill (manufactured by Ashizawa Finetech Co., Ltd., DMR type) using 0.05 mm zirconia beads and a filling rate of 55% at a peripheral speed of 10 m / s and a liquid temperature of 10 ° C. for 3 minutes. Coarse particles were centrifuged with a centrifuge (Model 7700, manufactured by Kubota Corporation) to obtain a pigment dispersion having a pigment concentration of 16% by mass.
[Prescription (1)]
・ Carbon black (NIPEX160, manufactured by degussa, BET specific surface area 150 m2 / g, average primary particle size 20 nm, pH 4.0, DBP oil absorption 620 g / 100 g)・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 160 parts by mass ・ Copolymer 1 (Synthesis Example 1) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ 40 parts by mass ・ Distilled water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 800 parts by mass

[Pigment Dispersion Preparation Example 2: Preparation of Black Pigment Dispersion 2]
Similar to Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed from 40 parts by mass to 20 parts by mass and distilled water was changed from 800 parts by mass to 820 parts by mass. Thus, a black pigment dispersion having a pigment concentration of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 3: Preparation of Black Pigment Dispersion 3]
Similar to Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed from 40 parts by mass to 160 parts by mass and distilled water was changed from 800 parts by mass to 680 parts by mass. Thus, a black pigment dispersion having a pigment concentration of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 4: Preparation of Black Pigment Dispersion 4]
Copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 is added to a 10% aqueous solution of POE (m = 40) β-naphthyl ether, its mass part is changed from 40 parts by mass to 400 parts by mass, and distilled water is 800 parts by mass. A black pigment dispersion having a pigment concentration of 16% by mass was obtained in the same manner as in Pigment Dispersion Preparation Example 1 except that the amount of the pigment was changed to 440 parts by mass.

[Pigment Dispersion Preparation Example 5: Preparation of Cyan Pigment Dispersion 1]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1, except that the carbon black of Pigment Dispersion Preparation Example 1 was changed to Pigment Blue 15: 3 (Dainipei Seika Co., Ltd., Chromofine Blue). A blue pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 6: Preparation of magenta pigment dispersion 1]
Similar to Pigment Dispersion Preparation Example 1, except that the carbon black of Pigment Dispersion Preparation Example 1 was changed to Pigment Red 122 (manufactured by Clariant, Toner Magenta EO02). A pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 7: Preparation of Yellow Pigment Dispersion 1]
A yellow pigment having a pigment concentration of 16% by mass was prepared in the same manner as in Pigment Dispersion Preparation Example 1 except that the carbon black of Pigment Dispersion Preparation Example 1 was changed to Pigment Yellow (First Yellow 531, manufactured by Dainichi Seika Co., Ltd.). A pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 8: Preparation of Black Pigment Dispersion 5]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 2 (Synthesis Example 2). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 9: Preparation of Black Pigment Dispersion 6]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 3 (Synthesis Example 3). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 10: Preparation of Black Pigment Dispersion 7]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 4 (Synthesis Example 4). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 11: Preparation of Black Pigment Dispersion 8]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 5 (Synthesis Example 5). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 12: Preparation of Black Pigment Dispersion 9]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 6 (Synthesis Example 6). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 13: Preparation of Black Pigment Dispersion 10]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 7 (Synthesis Example 7). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 14: Preparation of Black Pigment Dispersion 11]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 8 (Synthesis Example 8). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 15: Preparation of Black Pigment Dispersion 12]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 9 (Synthesis Example 9). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 15: Preparation of Black Pigment Dispersion 12]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 9 (Synthesis Example 9). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 16: Preparation of Black Pigment Dispersion 13]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 10 (Synthesis Example 10). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 17: Preparation of Black Pigment Dispersion 14]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 11 (Synthesis Example 11). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 18: Preparation of Black Pigment Dispersion 15]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 12 (Synthesis Example 12). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 19: Preparation of Black Pigment Dispersion 16]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 13 (Synthesis Example 13). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 20: Preparation of Black Pigment Dispersion 17]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 14 (Synthesis Example 14). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 21: Preparation of Black Pigment Dispersion 18]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 15 (Synthesis Example 15). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 22: Preparation of Black Pigment Dispersion 19]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 16 (Synthesis Example 16). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 23: Preparation of Black Pigment Dispersion 20]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 17 (Synthesis Example 17). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 24: Preparation of Black Pigment Dispersion 21]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 18 (Synthesis Example 18). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 25: Preparation of Black Pigment Dispersion 22]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 19 (Synthesis Example 19). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 26: Preparation of Black Pigment Dispersion 23]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 20 (Synthesis Example 20). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 27: Preparation of Black Pigment Dispersion 24]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) in Pigment Dispersion Preparation Example 1 was changed to the Copolymer 21 (Synthesis Example 21). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 28: Preparation of Black Pigment Dispersion 25]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 22 (Synthesis Example 22). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 29: Preparation of Black Pigment Dispersion 26]
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 23 (Synthesis Example 23). A black pigment dispersion was obtained.

[Pigment Dispersion Preparation Example 30: Preparation of Black Pigment Dispersion 27]
Pigment Concentration was the same as in Pigment Dispersion Preparation Example 1 except that Copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to Copolymer 24 (Synthesis Example 24 = Comparative Synthesis Example 1). A black comparative pigment dispersion having a weight of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 31: Preparation of Black Pigment Dispersion 28]
The pigment concentration was the same as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 25 (Synthesis Example 25 = Comparative Synthesis Example 2). A black comparative pigment dispersion having a weight of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 32: Preparation of Black Pigment Dispersion 29]
Pigment Concentration was the same as in Pigment Dispersion Preparation Example 1 except that Copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to Copolymer 26 (Synthesis Example 26 = Comparative Synthesis Example 3). A black comparative pigment dispersion having a weight of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 33: Preparation of Black Pigment Dispersion 30]
The pigment concentration was the same as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to the Copolymer 27 (Synthesis Example 27 = Comparative Synthesis Example 4). A black comparative pigment dispersion having a weight of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 34: Preparation of Black Pigment Dispersion 31]
Pigment concentration in the same manner as in Pigment Dispersion Preparation Example 1 except that Copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to Copolymer 28 (Synthesis Example 28 = Comparative Synthesis Example 5). A black comparative pigment dispersion having a weight of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 35: Preparation of Black Pigment Dispersion 32]
Pigment Concentration was the same as in Pigment Dispersion Preparation Example 1 except that Copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to Copolymer 29 (Synthesis Example 29 = Comparative Synthesis Example 6). A black comparative pigment dispersion having a weight of 16% by mass was obtained.

[Pigment Dispersion Preparation Example 36: Preparation of cyan pigment dispersion 2]
Carbon black of Pigment Dispersion Preparation Example 1 is Pigment Blue 15: 3 (Dainipei Seika Co., Ltd., Chromofine Blue), Copolymer 1 (Synthesis Example 1) is Copolymer 29 (Synthesis Example 29 = Comparative Synthesis Example) A blue comparative pigment dispersion having a pigment concentration of 16% by mass was obtained in the same manner as in Pigment Dispersion Preparation Example 1 except that the procedure was changed to 6).

[Pigment Dispersion Preparation Example 36: Preparation of cyan pigment dispersion 2]
Carbon black of Pigment Dispersion Preparation Example 1 is Pigment Blue 15: 3 (Dainipei Seika Co., Ltd., Chromofine Blue), Copolymer 1 (Synthesis Example 1) is Copolymer 29 (Synthesis Example 29 = Comparative Synthesis Example) A blue comparative pigment dispersion having a pigment concentration of 16% by mass was obtained in the same manner as in Pigment Dispersion Preparation Example 1 except that the procedure was changed to 6).

[Pigment dispersion preparation example 37: Preparation of magenta pigment dispersion 2]
Carbon black in Pigment Dispersion Preparation Example 1 is changed to Pigment Red 122 (Clariant, Toner Magenta EO02), and Copolymer 1 (Synthesis Example 1) is changed to Copolymer 29 (Synthesis Example 29 = Comparative Synthesis Example 6) Except that, a red-violet comparative pigment dispersion having a pigment concentration of 16% by mass was obtained in the same manner as in Pigment Dispersion Preparation Example 1.

[Pigment Dispersion Preparation Example 38: Preparation of Yellow Pigment Dispersion 2]
Carbon black of Pigment Dispersion Preparation Example 1 is Pigment Yellow (First Yellow 531 manufactured by Dainichi Seika Co., Ltd.), and Copolymer 1 (Synthesis Example 1) is Copolymer 29 (Synthesis Example 29 = Comparative Synthesis Example 6). A yellow comparative pigment dispersion having a pigment concentration of 16% by mass was obtained in the same manner as in Pigment Dispersion Preparation Example 1 except for the change.
Preparation examples of these pigment dispersions are summarized in the following table.

<Preparation Examples 1 to 58 of Pigment Dispersion>

<Preparation of ink for ink jet recording>
[Example 1]
As shown in Table 3, the materials of the following formulation are mixed and stirred for 1 hour to mix uniformly.
This dispersion was subjected to pressure filtration with a polyvinylidene fluoride membrane filter having an average pore size of 5.0 μm to remove coarse particles and dust, thereby producing a recording ink.
-Pigment dispersion 1 of pigment dispersion preparation example 1 (pigment concentration 16%) ... 50.0 parts by weight-Glycerin ... ... 10.0 parts by weight, 1,3-butanediol ... 20.0 parts by weight, pure Water ... 20.0 parts by weight

[Example 2]
A recording ink of Example 2 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. In addition, the numerical value in a table | surface shows the mass%.

[Example 3]
A recording ink of Example 3 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. In addition, the numerical value in a table | surface shows the mass%.

[Example 4]
A recording ink of Example 4 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 5]
A recording ink of Example 5 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 6]
A recording ink of Example 6 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 7]
A recording ink of Example 7 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 8]
A recording ink of Example 8 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 9]
A recording ink of Example 9 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 10]
A recording ink of Example 10 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 11]
A recording ink of Example 11 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 12]
A recording ink of Example 12 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 13]
A recording ink of Example 13 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 14]
A recording ink of Example 14 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 15]
A recording ink of Example 15 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 16]
A recording ink of Example 16 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 17]
A recording ink of Example 17 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 18]
A recording ink of Example 18 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 19]
A recording ink of Example 19 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 20]
A recording ink of Example 20 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 21]
A recording ink of Example 21 was produced in the same manner as Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 22]
A recording ink of Example 22 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 23]
A recording ink of Example 23 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 24]
A recording ink of Example 24 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 25]
A recording ink of Example 25 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 26]
A recording ink of Example 26 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 27]
A recording ink of Example 27 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 28]
A recording ink of Example 28 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 29]
A recording ink of Example 29 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 30]
A recording ink of Example 30 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Example 31]
A recording ink of Example 31 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 1]
A recording ink of Comparative Example 1 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 2]
A recording ink of Comparative Example 2 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 3]
A recording ink of Comparative Example 3 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 4]
A recording ink of Comparative Example 4 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 5]
A recording ink of Comparative Example 5 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 6]
A recording ink of Comparative Example 6 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 7]
A recording ink of Comparative Example 7 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 8]
A recording ink of Comparative Example 8 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

[Comparative Example 9]
A recording ink of Comparative Example 9 was produced in the same manner as in Example 1 except that the material having the formulation shown in Table 3 was used. The numerical value in a table | surface shows the mass%.

<Evaluation of storage stability of each pigment dispersion and each ink>
To measure the viscosity of each pigment dispersion and each recording ink in Preparation Examples 1 to 38, Examples 1 to 31, and Comparative Examples 1 to 9 of the pigment dispersion, a viscometer RE80L manufactured by Toki Sangyo Co., Ltd. was used. The viscosity at 25 ° C. was measured. About the rotation speed at the time of a viscosity measurement, it adjusted so that a torque might become fixed in 40%-80% of range. As an index of the dispersion stability of the pigment as the pigment dispersion and the ink, the initial viscosity after the preparation of the pigment dispersion and the ink was measured and evaluated based on the following criteria.
As for storage stability, after measuring the initial viscosity, each pigment dispersion and the ink are put in a polyethylene container, sealed, and measured after storage at 70 ° C. for 1 week, and the change from the initial viscosity is measured. The rate was evaluated based on the following criteria.

[Evaluation criteria for pigment dispersion]
(Initial viscosity)
A: Initial viscosity value is less than 3 mPa · s B: Initial viscosity value is 3 mPa · s or more and less than 7 mPa · s C: Initial viscosity value is 7 mPa · s or more

(Storability)
A: Change rate of viscosity after storage based on initial viscosity is less than 5% B: Change rate of viscosity after storage based on initial viscosity is 5% or more and less than 50% C: Viscosity after storage based on initial viscosity Change rate of 50% or more

[Ink evaluation criteria]
(Initial viscosity)
A: Initial viscosity value is less than 9 mPa · s B: Initial viscosity value is 9 mPa · s or more and less than 20 mPa · s C: Initial viscosity value is 20 mPa · s or more

(Storability)
A: Change rate of viscosity after storage based on initial viscosity is less than 5% B: Change rate of viscosity after storage based on initial viscosity is 5% or more and less than 50% C: Viscosity after storage based on initial viscosity Change rate of 50% or more

<Print evaluation of each ink set>
Printing evaluation was performed on the recording inks of Examples 1 to 31 and Comparative Examples 1 to 9.
Using an inkjet printer (IPSiO GX3000, manufactured by Ricoh Co., Ltd.), change the drive voltage of the piezo element so that the amount of ink discharged is uniform, and set so that the same amount of ink adheres to the recording material. went.
The viscosity of the ink was measured using a viscometer RE80L manufactured by Toki Sangyo Co., Ltd., and the viscosity at 25 ° C. was measured. The results are shown in Table 4.

<< Image density & showthrough >>
Using each ink, a chart containing general symbols of JIS X 0208 (1997), 2223 of 64 points created by Microsoft Word 2003 was printed on My Paper (manufactured by Ricoh), and then X-Rite 938 (X- The symbol portion was color-measured by Rite) to evaluate the image density. The print mode was “plain paper-fast” mode with the driver attached to the printer. The image density of each color was evaluated according to the following criteria. In the evaluation, four measurement locations per color were measured once for each chart, and the average value of the four locations was taken as the measurement result for each color. JIS X 0208 (1997), 2223 is a symbol whose outer shape is a regular square and the entire surface of the symbol is filled with ink.
Further, using X-Rite 938, the image density of the symbol part was measured from the back side of the paper, and the obtained OD value was used as the back-through density and evaluated according to the same criteria as described above.

[Image density (OD value) evaluation criteria]
A: OD value Black 1.25 or more
Yellow 0.80 or more
Magenta 0.95 or higher
Cyan 1.05 or more B: OD value Black 1.15 or more and less than 1.25
Yellow 0.75 or more and less than 0.80
Magenta 0.85 or more and less than 0.95
Cyan 0.95 or more and less than 1.05 C: OD value Black 1.05 or more and less than 1.15
Yellow 0.70 or more and less than 0.75
Magenta 0.75 or more and less than 0.85
Cyan 0.85 or more and less than 0.95 D: OD value Black Less than 1.05
Yellow less than 0.70
Less than magenta 0.75
Cyan less than 0.85.

[Evaluation criteria for strikethrough density]
A: OD value Black Less than 0.10
Yellow less than 0.08
Magenta less than 0.09
Cyan Less than 0.10 B: OD value Black 0.10 or more and less than 0.20
Yellow 0.08 or more and less than 0.16
Magenta 0.09 or more and less than 0.18
Cyan 0.10 or more and less than 0.20 C: OD value Black 0.20 or more and less than 0.50
Yellow 0.16 or more and less than 0.40
Magenta 0.18 or more and less than 0.40
Cyan 0.20 or more and less than 0.50 D: OD value Black 0.50 or more
Yellow 0.40 or more
Magenta 0.40 or higher
Cyan 0.50 or more

101 apparatus main body 102 paper feed tray 103 paper discharge tray 104 ink cartridge loading unit 105 operation unit 111 upper cover 112 front surface 115 front cover 131 guide rod 132 stay 133 carriage 134 recording head 135 sub tank 141 paper placement unit 142 paper 143 paper supply roller 144 Separator Pad 145 Guide 151 Conveyor Belt 152 Counter Roller 153 Conveyor Guide 154 Pressing Member 155 Tip Pressure Roller 156 Charging Roller 157 Conveying Roller 158 Densation Roller 161 Guide Member 171 Separation Claw 172 Discharge Roller 173 Discharge Roller 181 Double-sided Paper Feed Unit 182 Manual paper feed unit 200 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge exterior

JP 2007-153985 A JP 2011-122072 A JP 2008-214530 A

Claims (11)

In an inkjet recording ink having at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphate group, the copolymer containing the phosphate group has a structural unit represented by the general formula (1) and a structure at least chromatic and structural unit represented by the formula (2), a structural unit represented by the structural formula (3),
An ink for inkjet recording, wherein the constituent ratio of the structural unit represented by the general formula (1) in the copolymer containing a phosphoric acid group is 5 wt% to 80 wt% .
(R1 in the general formula (1) represents a hydrogen atom or a methyl group. M represents a hydrogen atom, an alkali metal, or an organic ammonium ion. N and m each represents an integer of 0 to 6 (provided that n , M must not be 0 at the same time)).
  2. The ink for inkjet recording according to claim 1, wherein the viscosity of the 10% by weight solid solution or aqueous dispersion of the copolymer containing phosphoric acid groups is 4.0 to 30.0 mPa · s. The ink for inkjet recording according to claim 1 or 2, wherein the constituent ratio of the structural unit represented by the general formula (2) in the copolymer containing a phosphoric acid group is 10% by weight to 35% by weight. 4. The inkjet recording according to claim 1, wherein a structural ratio of the structural unit represented by the general formula (3) in the copolymer containing a phosphate group is 50 wt% to 60 wt%. ink. The inkjet according to any one of claims 1 to 4, wherein a weight ratio of the pigment to the copolymer in the aqueous dispersion of the pigment containing the copolymer is pigment / copolymer = 100/10 to 100/100. Recording ink. The ink for inkjet recording according to any one of claims 1 to 5, wherein M in the general formula (1) constituting the copolymer is a hydrogen atom, a potassium atom, or a sodium atom. The ink for inkjet recording according to any one of claims 1 to 6, comprising glycerin as the water-soluble solvent. An ink storage container including an ink storage portion for storing ink, wherein the ink stored in the ink storage portion is the ink for ink jet recording according to any one of claims 1 to 7. Ink storage container. An ink jet recording apparatus that records information or an image on a recording medium by flying ink using an ink jet head, wherein the ink is the ink for ink jet recording according to any one of claims 1 to 7. An inkjet recording apparatus. A method for producing a recorded matter comprising a step of recording on a recording medium by discharging ink from an ink jet head, wherein the ink is the ink for ink jet recording according to any one of claims 1 to 7. A method for producing recorded material. A recorded matter in which information or an image is recorded on a recording medium using ink, wherein the ink is the ink for ink jet recording according to any one of claims 1 to 7.