JP2014201622A - Aqueous ink for inkjet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink for inkjet recording excellent in fixability and preservability of gloss of a printed matter and an image, and to provide a method for producing the aqueous ink for inkjet recording.SOLUTION: There is provided an aqueous ink for inkjet recording containing a coloring agent and polyester-based resin particles. The polyester-based resin particles contain an amorphous polyester-based resin(A) having an amorphous polyester moiety having a glass transition temperature of 40°C or more and 90°C or less and a crystalline polyester resin (B) as a polyester-based resin constituting the polyester-based resin particles and the mass ratio [the amorphous polyester-based resin(A)/the crystalline polyester resin (B)] of the amorphous polyester-based resin(A) to the crystalline polyester resin (B) is 55/45 to 97/3.

Description

  The present invention relates to an aqueous ink for inkjet recording, a method for producing the same, and an inkjet recording method.

  The ink jet recording system is a recording system in which characters and images are obtained by ejecting ink droplets directly from a very fine nozzle and attaching them to a recording member. This method is widely spread because it is easy to make full color and is inexpensive, and has many advantages such as the ability to use plain paper as a recording member and non-contact with the object to be printed.

Patent Document 1 discloses a water-based ink in which a pigment is dispersed and contains a substantially colorless and transparent polyester suspension for the purpose of improving fixability to a printing material and water resistance.
In Patent Document 2, for the purpose of improving fixability and gloss change, the dark ink composition contains at least a polyester emulsion, a pigment as a colorant, and a resin as a dispersant, and is alkali-soluble in a light ink composition. An ink set containing a dark ink composition and a light ink composition having the same color but different color densities, including at least an emulsion, a pigment as a colorant, and a resin as a dispersant is disclosed.
Patent Document 3 discloses an inkjet in which an ink composition is ejected as ink droplets by an inkjet recording method using an electrostatic field in order to improve blocking resistance and enable high-quality image fixing at low temperature and high speed. In the recording method, the ink composition to be used contains charged particles including a dispersion medium, a coloring material and a coating polymer thereof, and the dynamic elastic modulus of the coating polymer is 5 × 10 ⁵ Pa or more at 50 ° C., 70 ° C. 2 × 10 ⁵ Pa or less and 1 × 10 ³ Pa or more at 80 ° C. are disclosed.

Japanese Patent Laid-Open No. 10-46081 JP 2005-162981 A JP-A-2005-105161

Inkjet recording can be printed on any recording medium because it is non-contact with the substrate, but when water-based ink is used, water and the humectant are difficult to dry completely, and recording is also possible. Since it does not penetrate the medium sufficiently, it has become a problem that it has poor fixability and storage stability. Especially with coated paper that is inexpensive glossy paper and plastic film that is a non-absorbent medium, good images can be obtained, but penetration is difficult to occur, and fixing properties are insufficient even when the method of the above-mentioned patent document is used. It was. When resin particles or the like are blended in order to improve fixability, there is a problem that glossiness is lowered.
In view of the above problems, an object of the present invention is to provide a water-based ink for ink-jet recording which is excellent in fixability and excellent in gloss of printed matter and image storage, a method for producing the same, and an ink-jet recording method.

In order to solve the above-described problems with water-based inks, the inventors of the present invention need to quickly form a strong protective film with components in the ink after printing the ink on the surface of the recording medium. It was considered and considered. As a result, by including resin particles containing a specific amorphous polyester resin and a crystalline polyester resin, the fixability to a recording medium is improved, and the gloss of printed matter and the storage stability of an image are also improved. I found out that I can.
That is, the present invention provides the following [1] to [3].
[1] A water-based ink containing a colorant and polyester resin particles, wherein the polyester resin particles have a glass transition temperature of 40 ° C. or more and 90 ° C. or less as a polyester resin constituting the polyester resin particles. An amorphous polyester resin (A) having an amorphous polyester portion and an amorphous polyester resin (A) with respect to the crystalline polyester resin (B), which contains an amorphous polyester resin (A) and a crystalline polyester resin (B) The water-based ink for inkjet recording whose mass ratio [amorphous polyester resin (A) / crystalline polyester resin (B)] is 55/45 to 97/3.
[2] A method for producing a water-based ink for inkjet recording, comprising the following steps (1) to (3).
Step (1): The amorphous polyester (a1) having a non-aromatic carbon-carbon unsaturated bond having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower is mixed with the crystalline polyester resin (B), and then Step of mixing aqueous medium to obtain aqueous dispersion of resin mixture Step (2): Adding addition polymerizable monomer (a2) to the aqueous dispersion of resin mixture obtained in step (1) and polymerizing The crystalline polyester is made of a graft polymer (AG) composed of a segment (A1) derived from the amorphous polyester (a1) and a segment (A2) derived from the addition polymerizable monomer (a2). Graph wherein mass ratio of graft polymer (AG) to resin (B) [graft polymer (AG) / crystalline polyester resin (B)] is 55/45 to 97/3 Step of obtaining an aqueous dispersion of polyester resin particles containing a polymer (AG) and a crystalline polyester resin (B) Step (3): An aqueous dispersion of polyester resin particles obtained in step (2), and coloring Step 3 of mixing an aqueous dispersion containing an agent to obtain an aqueous ink for inkjet recording [3] After attaching an aqueous ink containing a colorant and polyester resin particles to a hardly absorbent medium by an inkjet recording method, In the ink jet recording method, the hardly absorbent medium is heated at 70 ° C. or more and 150 ° C. or less, wherein the polyester resin particles are used as a polyester resin constituting the polyester resin particles in one particle, and a glass transition is performed. An amorphous polyester resin (A) having an amorphous polyester portion having a temperature of 40 ° C. or higher and 90 ° C. or lower; and a crystalline polyester A mass ratio of the amorphous polyester resin (A) to the crystalline polyester resin (B) in the water-based ink [amorphous polyester resin (A) / crystal] Ink-jet recording method, wherein the curable polyester resin (B)] is 55/45 to 97/3.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based ink for inkjet recording which is excellent in fixability and excellent in the gloss of printed matter and the preservability of an image can be provided.

[1] Water-based ink for ink-jet recording The water-based ink for ink-jet recording of the present invention is a water-based ink containing a colorant and polyester resin particles, and the polyester resin particles are polyesters constituting the polyester resin particles. A crystalline polyester resin containing an amorphous polyester resin (A) having an amorphous polyester portion having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower, and a crystalline polyester resin (B). Inkjet wherein the mass ratio of the amorphous polyester resin (A) to the resin (B) [amorphous polyester resin (A) / crystalline polyester resin (B)] is 55/45 to 97/3 It is a water-based ink for recording.
In this specification, “water-based ink for inkjet recording” may be simply referred to as “water-based ink” or “ink”.

The reason why the water-based ink of the present invention is excellent in fixability and excellent in gloss of printed matter and image storage stability is not clear, but is considered as follows.
The water-based ink of the present invention contains polyester resin particles containing an amorphous polyester resin (A) and a crystalline polyester resin (B). Since the resin particles contain a large amount of the amorphous polyester resin (A), the resin particles have a structure in which the crystalline polyester resin (B) is finely dispersed in the amorphous polyester resin (A). Conceivable.
It is considered that when the ink of the present invention is printed on the surface of the recording medium, the resin particles are fused to form a film due to volatilization of the aqueous medium. In particular, the crystalline portion contained in the resin particles of the present invention exhibits an effect as a filler, and it is considered that a tough film is formed by recrystallization of crystals once melted or dissolved by heating and drying of a solvent or printed matter. . Accordingly, the water-based ink of the present invention is considered to have high fixability and excellent image storage stability.
In addition, while exhibiting the effects described above, the crystalline polyester resin (B) has a low viscosity when melted or dissolved by heating and drying of the solvent or printed matter, and a smooth film can be obtained. Since the subsequent crystals are also very finely dispersed in the amorphous polyester resin (A), the surface of the image becomes smooth and is considered to be excellent in gloss.
Hereinafter, each component and each process used for this invention are demonstrated.

[Colorant]
In the present invention, the colorant means a pigment or a dye. Further, as described later, the colorant may be made into fine particles that are stable in the ink using a surfactant or a polymer. The colorant used in the present invention is not particularly limited, and pigments, hydrophobic dyes, water-soluble dyes (acidic dyes, reactive dyes, direct dyes, etc.) can be used. From the viewpoint of scratch resistance, pigments and hydrophobic dyes are preferred. Among them, it is preferable to use a pigment in order to express the high weather resistance which has been recently demanded.

<Pigment>
The pigment may be either an inorganic pigment or an organic pigment. If necessary, they can be used in combination with extender pigments.
Examples of the inorganic pigment include carbon black and metal oxide, and carbon black is particularly preferable for black ink.
Specific examples of the organic pigment include azo pigments, diazo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalone pigments.
The hue is not particularly limited, and any chromatic pigment such as yellow, magenta, cyan, blue, red, orange, and green can be used.

Specific examples of preferred organic pigments include C.I. I. Pigment yellow, C.I. I. Pigment Red, C.I. I. Pigment orange, C.I. I. Pigment violet, C.I. I. Pigment blue, and C.I. I. One or more types of products selected from the group consisting of pigment green are listed. Of these, quinacridone pigments are preferred from the viewpoint of the color developability of the ink.
Moreover, solid solution pigments, such as a quinacridone solid solution pigment, can also be used suitably. The quinacridone solid solution pigment includes β-type and γ-type unsubstituted quinacridone and 2,9-dimethylquinacridone (CI Pigment Red 122), or β-type and γ-type unsubstituted quinacridone and 2,9- It consists of dichloroquinacridone such as dichloroquinacridone, 3,10-dichloroquinacridone, and 4,11-dichloroquinacridone. The quinacridone solid solution pigment is preferably a solid solution pigment composed of a combination of unsubstituted quinacridone (CI Pigment Violet 19) and 2,9-dichloroquinacridone (CI Pigment Red 202).

In the present invention, a self-dispersing pigment can also be used. Self-dispersing pigments are those in which one or more hydrophilic functional groups (anionic hydrophilic groups such as carboxy groups and sulfonic acid groups, or cationic hydrophilic groups such as quaternary ammonium groups) are directly or other atomic groups. It means an inorganic pigment or an organic pigment that can be dispersed in an aqueous medium without using a surfactant or a resin. Here, as another atomic group, a C1-C12 alkanediyl group, a phenylene group, a naphthylene group, etc. are mentioned.
The above pigments can be used alone or in admixture of two or more at any ratio.

<Colorants other than pigments>
The hydrophobic dye is not particularly limited as long as it can be contained in the polymer particles. The hydrophobic dye is dissolved in an amount of 2 g / L or more, preferably 20 to 500 g / L (25 ° C.) with respect to an organic solvent (preferably methyl ethyl ketone) used in the production of the polymer from the viewpoint of efficiently containing the dye in the polymer. What to do is desirable. Here, the hydrophobic dye means a dye having a solubility of preferably less than 6% by mass in 100 g of water (20 ° C.).
Examples of the hydrophobic dye include oil-soluble dyes and disperse dyes. Among these, oil-soluble dyes are preferable.
Examples of the oil-soluble dye include C.I. I. Solvent Black, C.I. I. Solvent Yellow, C.I. I. Solvent Red, C.I. I. Solvent Violet, C.I. I. Solvent Blue, C.I. I. Solvent Green, and C.I. I. One or more types of products selected from the group consisting of Solvent Orange are listed, which are commercially available from Orient Chemical Co., Ltd., BASF Corp. and others.
The above colorants can be used alone or in admixture of two or more at any ratio.

<Polymer particles containing colorant>
When the colorant is used in water-based ink, it is preferable to use a surfactant and a polymer to form fine particles that are stable in the ink. In particular, from the viewpoint of ink bleeding resistance, water resistance, and the like, it is more preferable to include a colorant in the polymer particles, and it is preferable to include a pigment and / or a hydrophobic dye in the polymer particles. More preferably, pigments and / or hydrophobic dyes are contained in the insoluble polymer particles.
Below, the polymer particle containing a coloring agent is demonstrated.

The average particle diameter of the polymer particles containing the colorant is preferably 40 to 200 nm, more preferably 50 to 150 nm, from the viewpoint of ink print density.
The average particle diameter of the polymer particles containing the colorant is measured by a dynamic light scattering method, and specifically measured by the method of the example.

(Water-insoluble polymer)
As the polymer particles containing a colorant, it is preferable to use a water-insoluble polymer from the viewpoints of water dispersibility of the polymer particles in the ink and improvement in the printing density of the ink. Here, the “water-insoluble polymer” refers to a polymer that has been dried at 105 ° C. for 2 hours and has reached a constant weight and dissolved in 100 g of water at 25 ° C., and its dissolved amount is 10 g or less. The dissolved amount is preferably 5 g or less, more preferably 1 g or less. In the case of an anionic polymer, the dissolution amount is the dissolution amount when the anionic group of the polymer is neutralized 100% with sodium hydroxide.
Examples of polymers used include polyesters, polyurethanes, and vinyl polymers. From the viewpoint of ink storage stability, vinyl polymers obtained by addition polymerization of vinyl monomers (vinyl compounds, vinylidene compounds, vinylene compounds). Polymers are preferred.

  The vinyl polymer includes (a) an ionic monomer (hereinafter also referred to as “(a) component”) and (b) a hydrophobic monomer (hereinafter referred to as “(b) component” from the viewpoints of ink storage stability and ejection properties. And a vinyl polymer obtained by copolymerizing a monomer mixture (hereinafter also simply referred to as “monomer mixture”). This vinyl polymer has a structural unit derived from the component (a) and a structural unit derived from the component (b). Especially, what contains the structural unit derived from (c) macromer (henceforth "(c) component") is preferable.

[(A) ionic monomer]
The (a) ionic monomer is preferably used as a monomer component of the water-insoluble polymer from the viewpoint of stably dispersing the polymer particles containing the colorant in the ink. Examples of the ionic monomer include an anionic monomer and a cationic monomer, and an anionic monomer is preferable.
Examples of the anionic monomer include a carboxylic acid monomer, a sulfonic acid monomer, and a phosphoric acid monomer.
Examples of the carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethyl succinic acid.
Among the anionic monomers, a carboxylic acid monomer is preferable, and acrylic acid and methacrylic acid are more preferable from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink.

[(B) Hydrophobic monomer]
(B) The hydrophobic monomer is preferably used as a monomer component of the water-insoluble polymer from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink. Here, the hydrophobic monomer means at least one of alkyl (meth) acrylate, styrene monomer, and aromatic group-containing (meth) acrylate.
As the alkyl (meth) acrylate, those having an alkyl group having 1 to 22 carbon atoms, preferably 6 to 18 carbon atoms are preferable. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meta) ) Acrylate, (iso or tertiary) butyl (meth) acrylate, (iso) amyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) Examples include decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, and (iso) stearyl (meth) acrylate.
In addition, “(iso or tertiary)” and “(iso)” mean both cases in which these groups are present and cases in which these groups are not present. “(Meth) acrylate” indicates acrylate and / or methacrylate.

As the styrenic monomer, styrene, 2-methylstyrene, and divinylbenzene are preferable, and styrene is more preferable.
Moreover, as an aromatic group containing (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, etc. are preferable, and benzyl (meth) acrylate is more preferable.
(B) Two or more types of the above-mentioned monomers can be used as the hydrophobic monomer. Styrenic monomers and aromatic group-containing (meth) acrylates can be used in combination, and benzyl (meth) acrylate and styrene can be used in combination, but it is more preferable to use benzyl (meth) acrylate alone.

[(C) Macromer]
(C) A macromer is a compound having a polymerizable functional group at one end and a number average molecular weight of 500 to 100,000, and from the viewpoint of storage stability in ink of polymer particles containing a colorant, a water-insoluble polymer. It is preferable to be used as a monomer component. The polymerizable functional group present at one end is preferably an acryloyloxy group or a methacryloyloxy group, and more preferably a methacryloyloxy group.
(C) The number average molecular weight of the macromer is preferably 1,000 to 10,000. The number average molecular weight is measured using polystyrene as a standard substance by gel permeation chromatography using chloroform containing 1 mmol / L dodecyldimethylamine as a solvent.
(C) As the macromer, from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink, an aromatic group-containing monomer-based macromer and a silicone-based macromer are preferable, and an aromatic group-containing monomer-based macromer is more preferable. .
Examples of the aromatic group-containing monomer constituting the aromatic group-containing monomer-based macromer include the aromatic group-containing monomers described in the above (b) hydrophobic monomer, styrene and benzyl (meth) acrylate are preferable, and styrene is more preferable. preferable.
Specific examples of the styrenic macromer include AS-6 (S), AN-6 (S), HS-6 (S) (trade name of Toagosei Co., Ltd.) and the like.
Examples of the silicone macromer include organopolysiloxane having a polymerizable functional group at one end.

[(D) Nonionic monomer]
For the water-insoluble polymer, from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink, (d) a nonionic monomer (hereinafter also referred to as “component (d)”) should be used as the monomer component. Is preferred.
(D) As a component, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, polypropylene glycol (n = 2-30, n shows the average addition mole number of an oxyalkylene group. The same hereafter). Polyalkylene glycol (meth) acrylate such as (meth) acrylate, polyethylene glycol (meth) acrylate (n = 2 to 30), and alkoxy polyalkylene glycol (meta) such as methoxypolyethylene glycol (n = 1 to 30) (meth) acrylate ) Acrylate, phenoxy (ethylene glycol / propylene glycol copolymer) (n = 1 to 30, ethylene glycol therein: n = 1 to 29) (meth) acrylate, and the like. Among these, alkoxy polyalkylene glycol (meth) acrylate is preferable, and methoxypolyethylene glycol (n = 1 to 30) (meth) acrylate is more preferable.

Specific examples of the commercially available component (d) include NK Esters M-20G, 40G, 90G, and 230G from Shin-Nakamura Chemical Co., Ltd., Bremer PE-90 from NOF Corporation, 200, 350, PME-100, 200, 400, PP-500, 800, etc., AP-150, 400, 550, 50PEP-300, 50POEP-800B, 43PAPE-600B, etc. .
The components (a) to (d) can be used alone or in admixture of two or more.

Components (a) to (d) in the monomer mixture of the above components (a) to (d) at the time of vinyl polymer production (contents as unneutralized amounts; the same applies hereinafter) or water-insoluble polymers The content of the structural unit derived from is as follows.
The content of the component (a) is preferably 3 to 40% by mass, more preferably 4 to 30% by mass, and particularly preferably 5 to 25% from the viewpoint of stably dispersing the polymer particles containing the colorant in the ink. % By mass.
The content of the component (b) is preferably 5 to 91% by mass, more preferably 10 to 80% by mass, from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink.
The content of the component (c) is preferably 1 to 25% by mass, more preferably 5 to 20% by mass, from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink.
The content of the component (d) is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink.
The mass ratio of [(a) component / [(b) component + (c) component]] is preferably 0.01 to from the viewpoint of dispersion stability of the polymer particles in the ink and ink printing density. 1, More preferably, it is 0.02-0.67, More preferably, it is 0.03-0.50.

(Production of water-insoluble polymer)
The water-insoluble polymer is produced by copolymerizing a monomer mixture by a known polymerization method. As the polymerization method, a solution polymerization method is preferable.
Although there is no restriction | limiting in the solvent used by the solution polymerization method, Polar organic solvents, such as C1-C3 aliphatic alcohol, ketones, ethers, and esters, are preferable, specifically, methanol, ethanol, acetone, and methyl ethyl ketone. And methyl ethyl ketone is preferred.
In the polymerization, a polymerization initiator or a polymerization chain transfer agent can be used. As the polymerization initiator, an azo compound is preferable, and 2,2′-azobis (2,4-dimethylvaleronitrile) is more preferable. . As the polymerization chain transfer agent, mercaptans are preferable, and 2-mercaptoethanol is more preferable.

Although preferable polymerization conditions vary depending on the type of polymerization initiator and the like, the polymerization temperature is preferably 50 to 80 ° C., and the polymerization time is preferably 1 to 20 hours. The polymerization atmosphere is preferably a nitrogen gas atmosphere or an inert gas atmosphere such as argon.
After completion of the polymerization reaction, the produced polymer can be isolated from the reaction solution by a known method such as reprecipitation or solvent distillation. In addition, unreacted monomers and the like can be removed from the obtained polymer by reprecipitation, membrane separation, chromatographic methods, extraction methods and the like.
The weight average molecular weight of the water-insoluble polymer used in the present invention is preferably 5,000 to 500,000 from the viewpoint of dispersion stability of the water-insoluble polymer particles containing the colorant in the ink and the printing density of the ink. 10,000-400,000 are more preferable, 10,000-300,000 are more preferable, and 20,000-200,000 are still more preferable. In addition, the measurement of a weight average molecular weight can be performed by the method as described in an Example.

<Production of polymer particles containing colorant>
The polymer particles containing the colorant can be efficiently produced by a method having the following steps I and II as an aqueous dispersion.
Step I: Step of dispersing a mixture containing a water-insoluble polymer, an organic solvent, a colorant, and water to obtain a dispersion of water-insoluble polymer particles containing a colorant Step II: Dispersion obtained in Step 1 A step of removing the organic solvent from the body to obtain an aqueous dispersion of water-insoluble polymer particles containing a colorant. Although it is an optional step, step III may be further performed.
Step III: A step of mixing the aqueous dispersion obtained in Step II and a crosslinking agent and crosslinking to obtain an aqueous dispersion

(Process I)
In Step I, first, the water-insoluble polymer is dissolved in an organic solvent, and then a colorant, water, and, if necessary, a neutralizing agent, a surfactant and the like are added to the obtained organic solvent solution and mixed. A method for obtaining an oil-in-water dispersion is preferred. Although there is no restriction | limiting in the order added to the organic solvent solution of a water-insoluble polymer, It is preferable to add in order of water, a neutralizing agent, and a coloring agent.
Although there is no restriction | limiting in the organic solvent in which a water-insoluble polymer is dissolved, C1-C3 aliphatic alcohol, ketones, ethers, esters, etc. are preferable, ketones are more preferable, and methyl ethyl ketone is still more preferable. When a water-insoluble polymer is synthesized by a solution polymerization method, the solvent used in the polymerization may be used as it is.
When the water-insoluble polymer is an anionic polymer, an anionic group in the water-insoluble polymer may be neutralized using a neutralizing agent. When using a neutralizing agent, it is preferable to neutralize so that pH may become 7-11. Examples of the neutralizing agent include bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, and various amines. Further, the water-insoluble polymer may be neutralized in advance.
The degree of neutralization of the anionic group of the water-insoluble polymer is preferably 10 to 300 mol%, more preferably 20 to 200 mol%, from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink. Preferably, 30 to 150 mol% is more preferable.
Here, the degree of neutralization is obtained by dividing the molar equivalent of the neutralizing agent by the molar amount of the anionic group of the water-insoluble polymer.

From the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink, the colorant in the dispersion is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and the organic solvent is 10 to 10% by mass. 70 mass% is preferable, 10-50 mass% is more preferable, 2-40 mass% is preferable, as for a water-insoluble polymer, 3-20 mass% is more preferable, and 10-70 mass% is preferable for water, and 20-20 mass% is preferable. 70 mass% is more preferable.
The mass ratio of the amount of the colorant to the amount of the water-insoluble polymer [colorant / water-insoluble polymer] is 50/50 to 90/10 from the viewpoint of dispersion stability of the polymer particles containing the colorant in the ink. It is preferable that it is 60 / 40-80 / 20, and it is still more preferable that it is 70 / 30-80 / 20.

There is no particular limitation on the dispersion method of the dispersion in Step I. Although the average particle diameter of the water-insoluble polymer particles containing the colorant can be atomized only by the main dispersion until the desired particle diameter is reached, preferably after pre-dispersion, the main dispersion is further subjected to shear stress. It is preferable to control the average particle size of the water-insoluble polymer particles containing the colorant to a desired particle size. The temperature in the dispersion in Step I is preferably 0 to 40 ° C, more preferably 0 to 25 ° C, and the dispersion time is preferably 1 to 30 hours, more preferably 2 to 25 hours.
When the dispersion is predispersed, a commonly used mixing and stirring device such as an anchor blade or a disper blade, particularly a high-speed stirring and mixing device is preferable.
Examples of means for applying the shear stress of the present dispersion include a kneader such as a roll mill and a kneader, a high-pressure homogenizer such as a microfluidizer (trade name, manufactured by Microfluidics), a media-type disperser such as a paint shaker and a bead mill. . Examples of commercially available media dispersers include Ultra Apex Mill (trade name, manufactured by Kotobuki Industries Co., Ltd.), Pico Mill (trade name, manufactured by Asada Tekko Co., Ltd.), and the like. A plurality of these devices can be combined. Among these, it is preferable to use a high-pressure homogenizer from the viewpoint of reducing the particle size of water-insoluble polymer particles containing a colorant.

(Step II)
In Step II, an aqueous dispersion of water-insoluble polymer particles containing a colorant can be obtained by removing the organic solvent from the obtained dispersion by a known method. The organic solvent in the aqueous dispersion containing the water-insoluble polymer particles containing the obtained colorant is preferably substantially removed, but may remain as long as the object of the present invention is not impaired. The amount of the residual organic solvent is preferably 0.1% by mass or less, and more preferably 0.01% by mass or less.
If necessary, the dispersion can be heated and stirred before the organic solvent is distilled off.
The obtained water dispersion of water-insoluble polymer particles containing a colorant is obtained by dispersing solid water-insoluble polymer particles containing a colorant in a medium containing water as a main medium. Here, the form of the water-insoluble polymer particles is not particularly limited as long as the particles are formed of at least a colorant and a water-insoluble polymer. For example, a particle form in which a colorant is included in the water-insoluble polymer, a particle form in which the colorant is uniformly dispersed in the water-insoluble polymer, a particle form in which the colorant is exposed on the surface of the water-insoluble polymer particle, and the like. Included, and mixtures thereof.

(Step III)
Step III is an optional step, but is a step in which the aqueous dispersion obtained in Step II and a crosslinking agent are mixed and crosslinked to obtain an aqueous dispersion. It is preferable to perform step III from the viewpoint of storage stability of the aqueous dispersion and the ink.
Here, in the case where the water-insoluble polymer is an anionic water-insoluble polymer having an anionic group, the crosslinking agent is preferably a compound having a functional group that reacts with the anionic group, and the functional group has two or more functional groups in the molecule. , Preferably 2 to 6 are more preferable.
Preferred examples of the crosslinking agent include compounds having two or more epoxy groups in the molecule, compounds having two or more oxazoline groups in the molecule, and compounds having two or more isocyanate groups in the molecule. Then, a compound having two or more epoxy groups in the molecule is preferable, and trimethylolpropane polyglycidyl ether is more preferable.

[Polyester resin particles]
The polyester resin particles used in the present invention are amorphous polyester resins having an amorphous polyester portion having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower as the polyester resin constituting the polyester resin particles ( A) and a crystalline polyester resin (B) are contained.
The polyester resin particles used in the present invention are resin mixture particles containing the above amorphous polyester resin (A) and crystalline polyester resin (B) as a resin in one particle.
In addition to these amorphous polyester resin (A) and crystalline polyester resin (B), the polyester resin particles used in the present invention are components such as other resins as long as the object of the present invention is not impaired. May be contained. However, from the viewpoint of obtaining a water-based ink having excellent fixability and excellent gloss of printed matter and image storability, these amorphous polyester resin (A) and crystalline polyester resin (B) in the polyester resin particles are used. ) Is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 99% by mass or more, and still more preferably 100% by mass.
Next, the physical properties of these amorphous polyester resin (A), crystalline polyester resin (B) and polyester resin particles containing them will be described in this order.

<Amorphous polyester resin (A)>
The amorphous polyester resin (A) used in the present invention has an amorphous polyester portion having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower.
Here, “including the amorphous polyester portion” includes a case where the amorphous polyester portion alone is included, and a case where the amorphous polyester portion and the other portion are included. However, from the viewpoint of obtaining a water-based ink having excellent fixability and excellent gloss of printed matter and image storability, the amorphous polyester resin (A) is composed of the segment (A1) ( Hereinafter, “polyester resin segment (A1)” or “segment (A1)”) and addition polymerization resin segment (A2) (hereinafter referred to as “addition polymerization resin segment (A2)” or “segment (A2)”) It is preferable that the polymer is a graft polymer (AG).

(Amorphous polyester part)
When the amorphous polyester portion is an amorphous polyester resin composed only of an amorphous polyester portion, it means the amorphous polyester resin (A) itself, and the amorphous polyester resin (A ) Is a graft polymer (AG), it means the polyester resin segment (A1) constituting a part of the graft polymer (AG).
In the present invention, the amorphous polyester means the ratio of the softening point to the maximum endothermic peak temperature by a differential scanning calorimeter (DSC), (softening point (° C.)) / (Maximum endothermic peak temperature (° C.)). A polyester having a defined crystallinity index of more than 1.4 or less than 0.6.
The amorphous polyester preferably has a crystallinity index of less than 0.6 or more than 1.4 and 4 or less, more preferably from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink. Is less than 0.6 or 1.5 or more and 4 or less, more preferably less than 0.6 or 1.5 or more and 3 or less, more preferably less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be adjusted by the type and ratio of raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like.

[Alcohol component]
Examples of the alcohol component, which is a raw material monomer for the amorphous polyester portion, include aromatic diols, aliphatic diols, alicyclic diols, trivalent or higher alcohols, and the like. From the viewpoint of improvement, it is preferably an alicyclic diol or an aromatic diol, more preferably an aromatic diol, and even more preferably two kinds of alicyclic diol and aromatic diol.
The aromatic diol preferably contains an alkylene oxide adduct of bisphenol A from the viewpoint of improving the fixability, gloss, and image storage stability of the water-based ink.
The alkylene oxide adduct of bisphenol A is preferably at least one of a propylene oxide adduct and an ethylene oxide adduct of bisphenol A, more preferably from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink. Are two types.
When these two types are used, the proportion of the propylene oxide adduct of bisphenol A in the total amount of these two types is preferably 55 mol% or more, more preferably 60 mol% or more, and preferably 90 mol% or less. More preferably, it is 80 mol% or less, More preferably, it is 70 mol% or less.
The number of adducts per molecule of the alkylene oxide adduct of bisphenol A is preferably 1.5 or more, more preferably 1.8 from the viewpoint of improving the fixing property, glossiness, and image storage stability of the water-based ink. More preferably, it is 2 or more, preferably 5 or less, more preferably 3 or less, still more preferably 2.5 or less.
The content of the alkylene oxide adduct of bisphenol A in the aromatic diol is preferably 50 mol% or more, more preferably 55 mol% or more, from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink. Further, it is preferably 60 mol% or more, more preferably 70 mol% or more, and preferably 100 mol% or less, more preferably 90 mol% or less, still more preferably 85 mol% or less, and still more preferably 80 mol% or less. It is less than mol%.

The alicyclic diol is preferably a bisphenol A hydride from the viewpoint of improving the fixability, glossiness and image storage stability of the water-based ink.
As the aliphatic diol, an aliphatic diol having 2 to 4 carbon atoms is preferable, and 1,2-propanediol is more preferable.
Examples of the trihydric or higher alcohol include glycerin, pentaerythritol, trimethylolpropane, and the like.

[Carboxylic acid component]
Examples of the carboxylic acid component that is a raw material monomer of the amorphous polyester part include aromatic dicarboxylic acid, aliphatic dicarboxylic acid, trivalent or higher dicarboxylic acid, and the like. From the viewpoint of improvement, it is preferable to include an aromatic dicarboxylic acid, and it is more preferable to include both an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid.
Specific examples of the aromatic dicarboxylic acid are preferably at least one of phthalic acid, isophthalic acid, and terephthalic acid, and more preferably isophthalic acid.
Specific examples of the aliphatic dicarboxylic acid include fumaric acid, maleic acid, oxalic acid, malonic acid, and adipic acid. From the viewpoint of improving the fixability, glossiness, and image storage stability of aqueous inks, fumaric acid and adipine are used. At least one acid is preferred.
Examples of the trivalent or higher carboxylic acid include aromatic carboxylic acids such as trimellitic acid, 2,5,7-naphthalene tricarboxylic acid, and pyromellitic acid.
In the present invention, the carboxylic acids described in the carboxylic acid component include free acids, anhydrides of these acids, and alkyls having 1 to 3 carbon atoms that can be used as raw materials for producing polyester. Including alkyl ester having a group.

<Graft polymer (AG)>
The amorphous polyester resin (A) constituting the polyester resin particles is a graft polymer (AG) composed of a segment (A1) made of an amorphous polyester resin and a segment (A2) made of an addition polymerization resin. Preferably there is. By using the graft polymer (AG) as described above, the image storability of the water-based ink is remarkably improved, and the fixability is also improved.
Next, the physical properties of the segment (A1), the segment (A2), and the graft polymer (AG) will be described in this order.

(Polyester resin segment (A1))
The polyester resin segment (A1) constituting the graft polymer (AG) is a resin segment obtained by condensation polymerization of an alcohol component and a carboxylic acid component, and is the amorphous polyester portion. In order to form a binding portion with the segment (A2) in the graft polymer (AG), the carboxylic acid component of the segment (A1) is a carboxylic acid having a non-aromatic carbon-carbon unsaturated bond, such as an unsaturated group. It preferably contains a saturated aliphatic carboxylic acid and / or an unsaturated alicyclic carboxylic acid. When the carbon-carbon unsaturated bond portion becomes a bond portion with the segment (A2) in the graft polymer (AG), the unsaturated bond becomes a saturated bond.

  Examples of carboxylic acids having non-aromatic carbon-carbon unsaturated bonds (unsaturated aliphatic carboxylic acids and unsaturated alicyclic carboxylic acids) include unsaturated fats such as fumaric acid, maleic acid, acrylic acid, and methacrylic acid. Group carboxylic acid; dicarboxylic acid such as unsaturated alicyclic carboxylic acid such as tetrahydrophthalic acid. From the viewpoint of reactivity, fumaric acid, maleic acid and tetrahydrophthalic acid are preferable, and fumaric acid is more preferable.

  The content of the carboxylic acid having a non-aromatic carbon-carbon unsaturated bond in the carboxylic acid component is preferably 3 mol from the viewpoint of improving the cross-linking degree and improving the fixability of the water-based ink and the image storage stability. % Or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, still more preferably 12 mol% or more. From the viewpoint of improving gloss, it is preferably 30 mol% or less, more preferably 25 mol%. It is not more than mol%, more preferably not more than 20 mol%, still more preferably not more than 18 mol%.

  In the segment (A1), from the viewpoint of appropriately adjusting the particle diameter of the resin particles and improving the fixing strength of the ink to the recording medium, the molar ratio of the hydroxyl group of the alcohol component to the carboxy group of the carboxylic acid component (hydroxyl group / carboxyl). The group) is preferably 100/90 to 100/120, more preferably 100/95 to 100/110, still more preferably 100/95 to 100/105.

(Segment made of addition polymerization resin (A2))
The segment (A2) constituting the graft polymer (AG) is a segment made of an addition polymerization resin composed of a structural unit derived from the addition polymerizable monomer (a2) (hereinafter also referred to as “monomer (a2)”).
Examples of the addition polymerizable monomer (a2) used in the present invention include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, t-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid or the like. Styrenes such as salts; (meth) acrylic acid esters such as alkyl (meth) acrylate (1 to 18 carbon atoms), benzyl (meth) acrylate, dimethylaminoethyl (meth) acrylate; ethylene, propylene, butadiene, etc. Olefins such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; N-vinyl compounds such as N-vinyl pyrrolidone; Or one or more of It is.
Among these, one or two of styrenes and (meth) acrylic acid esters are preferable, and two are more preferable, from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink.
The addition polymerizable monomer having an aromatic group is preferably one or more of styrene, methylstyrene, phenoxyethylene glycol (meth) acrylate, benzyl methacrylate, and benzyl acrylate. Among these, one or two of styrene and phenoxyethylene glycol (meth) acrylate are preferable, and styrene is more preferable from the viewpoint of the raw material price of the monomer.
The (meth) acrylic acid ester preferably has an alkyl group having 1 to 22 carbon atoms, preferably 6 to 18 carbon atoms. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meta) ) Acrylate, (iso or tertiary) butyl (meth) acrylate, (iso) amyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) Examples include decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, (iso) stearyl (meth) acrylate, lauryl acrylate, etc., preferably 2-ethylhexyl (meth) acrylate and (iso) stearyl (meth) acrylate. One or two , More preferably 2-ethylhexyl (meth) acrylate.
The addition polymerizable monomer (a2) is preferably a combination of at least one of the above (meth) acrylic acid esters and styrene, more preferably 2-ethylhexyl (meth) acrylate and (iso) stearyl (meth) acrylate. Or a combination of styrene and more preferably a combination of 2-ethylhexyl (meth) acrylate and styrene.
The content of the structural unit derived from the addition polymerizable monomer having an aromatic group is preferably 10 mass in the segment (A2) from the viewpoint of improving the fixing property, glossiness, and image storage stability of the water-based ink. % Or more, more preferably 30% by weight or more, still more preferably 40% by weight or more, further preferably 50% by weight or more, preferably 100% by weight or less, more preferably 80% by weight or less, still more preferably 70% by weight. Hereinafter, it is more preferably 60% by mass or less.
The structural unit derived from (meth) acrylic acid ester is preferably used in combination with styrene from the viewpoint of the initial fixability and fixing strength of the ink on the recording medium, and the structural unit derived from (meth) acrylic acid ester. The content of is preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass in the segment (A2) from the viewpoints of ink ejection properties, initial fixability to a recording medium, and fixing strength. % Or more, preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 50% by mass or less, and further preferably 49% by mass or less.

  The mass ratio of the segment (A2) and the unsaturated carboxylic acid (that is, the total of unsaturated aliphatic carboxylic acid and unsaturated alicyclic carboxylic acid) in the raw material monomer of the segment (A1) [segment (A2) / segment ( A1) Unsaturated carboxylic acid in raw material monomer] is preferably 0.1 to 10, more preferably 0.1 to 1, and still more preferably 0.2 to 0.4 from the viewpoint of fixability of the water-based ink. It is.

(Physical properties of graft polymer (AG))
The mass ratio [segment (A1) / segment (A2)] of the segment (A1) and the segment (A2) constituting the graft polymer (AG) is a viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink. Therefore, it is preferably 55/45 or more, more preferably 60/40 or more, still more preferably 65/35 or more, preferably 95/5 or less, more preferably 90/10 or less, still more preferably 85. / 15 or less, more preferably 80/20 or less, and still more preferably 75/25 or less.
It is considered that the presence of more segments (A1) than segments (A2) increases the affinity with water, improves the film-forming properties, and the fixing properties to the recording medium.

The glass transition temperature (Tg2) of the graft polymer (AG) is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, and still more preferably, from the viewpoint of the initial fixability and fixing strength of the ink to the recording medium. 60 ° C. or higher, more preferably 63 ° C. or higher, preferably 80 ° C. or lower, more preferably 75 ° C. or lower, still more preferably 70 ° C. or lower, still more preferably 68 ° C. It is as follows.
In addition to the case where the resin particles (A) are constituted only by the graft polymer (AG), the resin particles (A) may further contain components other than resins such as other resins and activators. In the present invention, the glass transition temperature (Tg2) of the resin constituting the resin particle (A) means that the resin particle (A) contains a resin other than the graft polymer (AG) and a component other than the resin. The measurement value regarding the peak corresponding to the graft polymer (AG) when the resin particle (A) containing the whole is measured by the measurement method described in the examples.

<Method for producing graft polymer (AG)>
As a method for producing the graft polymer (AG), an alcohol component and a carboxylic acid component are subjected to polycondensation to form an amorphous polyester resin (a1) having a non-aromatic carbon-carbon unsaturated bond (hereinafter referred to as “resin ( a1) ”) and addition polymerization of the addition polymerizable monomer (a2) in the presence of the polyester resin (a1) is preferred.

(Amorphous polyester resin (a1))
The resin (a1) is an amorphous polyester resin having a non-aromatic carbon-carbon unsaturated bond, obtained by condensation polymerization of an alcohol component and a carboxylic acid component, and a segment (A1) made of the polyester resin. ) Is preferable. The “non-aromatic carbon-carbon unsaturated bond” is derived from one or more selected from the unsaturated aliphatic carboxylic acids and unsaturated alicyclic carboxylic acids described above.

  The suitable kind and suitable content of the alcohol component and carboxylic acid component of the resin (a1) are the same as those in the segment (A1). Therefore, the preferred content of at least one of the unsaturated aliphatic carboxylic acid and unsaturated alicyclic carboxylic acid in the amorphous polyester (a1) is not limited to the unsaturated aliphatic carboxylic acid and unsaturated carboxylic acid in the segment (A1). It is the same as the preferable content of at least one kind of saturated alicyclic carboxylic acid.

The amorphous polyester resin (a1) is, for example, polycondensation of the alcohol component and the carboxylic acid component in an inert gas atmosphere at a temperature of 180 to 250 ° C. using an esterification catalyst as necessary. Can be manufactured.
From the viewpoints of ink ejection properties, fixing strength to the recording medium, and control of the particle size of the resin particles, the polyester preferably has a sharp molecular weight distribution and is preferably subjected to polycondensation using an esterification catalyst. Examples of the esterification catalyst include metal compounds such as tin catalyst, titanium catalyst, antimony trioxide, zinc acetate, and germanium dioxide. From the viewpoint of the reaction efficiency of the esterification reaction in the synthesis of the polyester, a tin catalyst is preferable. As the tin catalyst, dibutyltin oxide, tin octylate, salts thereof and the like are preferably used, and tin octylate is more preferably used. Moreover, you may use together a radical polymerization inhibitor.

From the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink, the softening point of the resin (a1) is preferably 70 ° C or higher, more preferably 90 ° C or higher, still more preferably 100 ° C or higher, and still more preferably. Is 110 ° C. or higher, preferably 150 ° C. or lower, more preferably 140 ° C. or lower, still more preferably 130 ° C. or lower, and still more preferably 125 ° C. or lower.
Similarly, the glass transition temperature (Tg1) of the resin (a1) is 40 ° C. or higher, preferably 50 ° C. or higher, more preferably 60 ° C., from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink. More preferably, the temperature is 70 ° C. or higher, 90 ° C. or lower, preferably 85 ° C. or lower, more preferably 80 ° C. or lower, and further preferably 75 ° C. or lower.
From the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink, the acid value of the resin (a1) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 15 mgKOH / g or more, More preferably, it is 18 mgKOH / g or more, Preferably it is 40 mgKOH / g or less, More preferably, it is 30 mgKOH / g or less, More preferably, it is 25 mgKOH / g or less, More preferably, it is 23 mgKOH / g or less.
The polyester resin (a1) preferably has a crystallinity index of less than 0.6 or more than 1.4 and 4 or less from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink. Preferably it is less than 0.6 or 1.5 or more and 4 or less, More preferably, it is less than 0.6 or 1.5 or more and 3 or less, More preferably, it is less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be adjusted by the type and ratio of raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like.
The glass transition temperature, softening point, and acid value can all be obtained by appropriately adjusting the type of monomer used, the blending ratio, the temperature of condensation polymerization, and the reaction time.
Further, from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink, the number average molecular weight of the resin (a1) is preferably 1,000 or more, more preferably 2,000 or more, and still more preferably 2, 500 or more, more preferably 3,000 or more, preferably 10,000 or less, more preferably 6,000 or less, still more preferably 5,000 or less, and still more preferably 4,000. It is as follows.
(Addition polymerizable monomer (a2))
The addition polymerizable monomer (a2) used in the present invention is as described above.

<Crystalline polyester resin (B)>
The water-based ink containing the colorant and the polyester resin particles according to the present invention includes a crystalline polyester resin (B) together with the amorphous polyester resin (A) as a polyester resin constituting the polyester resin particles. ).
In the present invention, the crystalline polyester resin is the ratio between the softening point and the maximum peak temperature of endotherm measured by a differential scanning calorimeter (DSC), (softening point (° C.)) / (Maximum endothermic peak temperature (° C.)). It means a polyester resin having a defined crystallinity index of 0.6 to 1.4, and preferably 0.8 to 1.3 from the viewpoint of low-temperature fixability of the toner. 2 is more preferable, and 0.9 to 1.1 is more preferable.

(Alcohol component)
The alcohol component which is a raw material monomer of the crystalline polyester resin (B) preferably contains an α, ω-aliphatic diol having 8 to 14 carbon atoms. When the number of carbon atoms is 8 or more, the adhesive strength with PET is improved and the fixability is improved, and the compatibility with the amorphous polyester resin (A) is well controlled and the image storage stability is improved. To do. Further, when the carbon number is 14 or less, the adhesive force with the amorphous polyester resin (A) is improved and the fixing property is improved. From this viewpoint, the alcohol component more preferably contains an α, ω-alkanediol having 8 to 14 carbon atoms.
Specific examples of such aliphatic diols include 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecane. Candiol, 1,14-tetradecanediol and the like are mentioned, and from the viewpoint of the fixing strength of the ink, among these, 1,9-nonanediol, 1,10-decanediol and 1,12-dodecanediol are preferable. 1,10-decanediol and 1,12-dodecanediol are more preferable.

  The content of the α, ω-aliphatic diol having 8 to 14 carbon atoms is preferably 70 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol in the alcohol component from the viewpoint of the fixing strength of the ink. % Or more, more preferably 100 mol%.

  Examples of the alcohol component other than the α, ω-aliphatic diol having 8 to 14 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,5-pentanediol, and 1,6-hexanediol. And aliphatic diols having 2 to 7 carbon atoms such as neopentyl glycol; aromatic diols such as alkylene oxide adducts of bisphenol A; trivalent or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane.

(Carboxylic acid component)
The carboxylic acid component that is a raw material monomer of the crystalline polyester resin (B) is preferably an aliphatic dicarboxylic acid.
The aliphatic dicarboxylic acid preferably has a carbon number from the viewpoint of improving adhesiveness and fixing properties, and improving compatibility with the amorphous polyester resin (A) to improve image storage stability. 4 or more, more preferably 6 or more carbon atoms, still more preferably 8 or more carbon atoms. The aliphatic dicarboxylic acid preferably has 14 or less carbon atoms, more preferably 13 or less carbon atoms, still more preferably 12 or less carbon atoms, and still more preferably from the viewpoint of improving the fixability. It has 11 or less carbon atoms.
In the present invention, the carboxylic acids described in the carboxylic acid component include free acids, anhydrides of these acids, and alkyls having 1 to 3 carbon atoms that can be used as raw materials for producing polyester. Including alkyl ester having a group.
Specific examples of such dicarboxylic acids are preferably sebacic acid, dodecanedioic acid, adipic acid, succinic acid, and fumaric acid, more preferably sebacic acid, dodecanedioic acid, and adipic acid, and more preferably sebacic acid. is there.

The content of the dicarboxylic acid having 4 to 14 carbon atoms is 10 mol% or more, preferably 50 mol% or more, more preferably from the viewpoint of ink fixing property, glossiness and image storage stability. It is 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably 100 mol%.
In addition, there is no restriction | limiting in particular in the manufacturing method of this crystalline polyester resin (B), A well-known manufacturing method is applicable.

(Physical properties of crystalline polyester resin (B))

From the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink, the melting point of the crystalline polyester resin (B) is 50 ° C. or higher, preferably 60 ° C. or higher, more preferably 65 ° C. or higher, and still more preferably. Is 70 ° C. or higher, 100 ° C. or lower, preferably 90 ° C. or lower, more preferably 80 ° C. or lower, and further preferably 75 ° C. or lower.
Similarly, the softening point of the crystalline polyester resin (B) is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and further preferably 65 ° C. from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink. As mentioned above, it is 70 degreeC or more more preferably, Preferably it is 100 degrees C or less, More preferably, it is 90 degrees C or less, More preferably, it is 80 degrees C or less, More preferably, it is 75 degrees C or less.
From the viewpoint of improving the fixing property, glossiness, and image storage stability of the water-based ink, the acid value of the crystalline polyester resin (B) is preferably 1 mgKOH / g or more, more preferably 10 mgKOH / g or more, and further preferably 15 mgKOH / g or more, more preferably 20 mgKOH / g or more, preferably 35 mgKOH / g or less, more preferably 30 mgKOH / g or less, still more preferably 25 mgKOH / g or less, still more preferably 23 mgKOH / g or less.
The glass transition temperature, softening point, and acid value can all be obtained by appropriately adjusting the type of monomer used, the blending ratio, the temperature of condensation polymerization, and the reaction time.
Further, from the viewpoint of improving the fixability, glossiness, and image storage stability of the water-based ink, the number average molecular weight of the crystalline polyester resin (B) is preferably 1,000 or more, more preferably 3,000 or more, and still more preferably. Is 4,000 or more, more preferably 4,500 or more, preferably 10,000 or less, more preferably 8,000 or less, still more preferably 7,000 or less, still more preferably 6,000 or less.

<Physical properties of polyester resin particles>
In the water-based ink containing the colorant and the polyester resin particles according to the present invention, the polyester resin constituting the polyester resin particles is an amorphous polyester portion having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower as described above. Amorphous polyester resin (A) having a crystallinity and a crystalline polyester resin (B).
The mass ratio of the amorphous polyester resin (A) to the crystalline polyester resin (B) [amorphous polyester resin (A) / crystalline polyester resin (B)] is 55/45 to 97/3. It is. When the mass ratio is 55/45 or more, the amorphous polyester resin (A) has a structure in which a small amount of the crystalline polyester resin (B) is finely dispersed, thereby improving the image storage stability and the ink. The fixing property and glossiness of the toner are improved. Further, when the mass ratio is 97/3 or less, the fixing property and glossiness of the ink by the crystalline polyester resin (B) are improved. From this viewpoint, the mass ratio is preferably 60/40 or more, more preferably 65/35 or more, still more preferably 70/30 or more, and preferably 95/5 or less, more preferably 90/10 or less. More preferably, it is 85/15 or less.
The volume median particle size of the polyester resin particles is preferably 0.02 μm or more, more preferably 0.10 μm or more, more preferably 0, from the viewpoint of improving the fixability, glossiness and image storage stability of the water-based ink. .20 μm or more, preferably 0.25 μm or less, more preferably 0.24 μm or less, and still more preferably 0.23 μm or less.
Here, the “volume median particle size” means a particle size at which the cumulative volume frequency measured by the volume fraction becomes 50% cumulative from the smaller particle size. The measuring method is as described in the examples.

[Physical properties of water-based ink for inkjet recording]
The content of the colorant contained in the aqueous ink of the present invention is preferably 1 to 25% by mass, more preferably 2 to 10% by mass in the aqueous ink from the viewpoint of increasing the print density and dispersion stability of the aqueous ink. More preferably, it is 3 to 5% by mass.
The content of the polyester resin particles contained in the water-based ink of the present invention is the water-based ink from the viewpoint of improving the discharge property of the water-based ink, the initial fixing property to the recording medium, the fixing strength, and the image storability at high temperature. Preferably it is 1% by mass or more, more preferably 3% by mass or more, preferably 5% by mass or more, preferably 7% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, preferably It is 10 mass% or less, Preferably it is 9 mass% or less.
The content of water contained in the aqueous ink of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 50% by mass in the aqueous ink from the viewpoint of improving the dischargeability of the aqueous ink. % Or more, preferably 55% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, preferably 70% by mass or less, preferably 65% by mass or less.
The mass ratio of the colorant to the polyester resin particles contained in the water-based ink of the present invention [colorant / polyester resin particles] is a water-based ink from the viewpoint of the discharge property of the water-based ink, the initial fixability to the recording medium, and the fixing strength. In the ink, it is preferably 10/90 to 80/20, more preferably 20/80 to 60/40, still more preferably 25/75 to 50/50, still more preferably 30/70 to 40/60. is there.

[Optional components of water-based ink]
The water-based ink of the present invention can contain various additives such as organic solvents, penetrants, dispersants, surfactants, viscosity modifiers, antifoaming agents, antiseptics, antifungal agents, and rust inhibitors.
Examples of organic solvents include glycerol, 1,2-hexanediol, diethylene glycol, ethylene glycol, acetylene glycol and other polyhydric alcohols, 2-pyrrolidone and other pyrrolidones, triethylene glycol monobutyl ether and polyoxyethylene lauryl ether and other glycol ethers. Preferably, two or more of these are used in combination.
In the present invention, the content of the organic solvent is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more in the aqueous ink from the viewpoint of improving the dischargeability of the aqueous ink. Moreover, it is preferably 40% by mass or less, more preferably 35% by mass or less, and still more preferably 30% by mass or less.

  In the present invention, the content of the surfactant is preferably 0.1 to 5% by mass, more preferably 0.5 to 2% by mass in the aqueous ink from the viewpoint of improving the dischargeability of the aqueous ink. is there.

[2] Method for Producing Water-based Ink for Inkjet Recording The method for producing water-based ink for ink-jet recording of the present invention is not limited.
Next, a preferred example of the method for producing the aqueous ink for ink jet recording of the present invention will be described.
The suitable example of the manufacturing method of the water-based ink for inkjet recording of this invention has the following process (1)-(3).
Step (1): The amorphous polyester (a1) having a non-aromatic carbon-carbon unsaturated bond having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower is mixed with the crystalline polyester resin (B), and then Step of mixing aqueous medium to obtain aqueous dispersion of resin mixture Step (2): Adding addition polymerizable monomer (a2) to the aqueous dispersion of resin mixture obtained in step (1) and polymerizing The crystalline polyester is made of a graft polymer (AG) composed of a segment (A1) derived from the amorphous polyester (a1) and a segment (A2) derived from the addition polymerizable monomer (a2). Graph wherein mass ratio of graft polymer (AG) to resin (B) [graft polymer (AG) / crystalline polyester resin (B)] is 55/45 to 97/3 Step of obtaining an aqueous dispersion of polyester resin particles containing a polymer (AG) and a crystalline polyester resin (B) Step (3): An aqueous dispersion of polyester resin particles obtained in step (2), and coloring Mixing with an aqueous dispersion containing an agent to obtain an aqueous ink for inkjet recording

According to the production method, after mixing the amorphous polyester (a1) and the crystalline polyester resin (B), the amorphous polyester (a1) is polymerized with the addition polymerizable monomer (a2), thereby producing one particle. Polyester resin particles containing the amorphous polyester resin (A) and the crystalline polyester resin (B) therein can be easily produced. Further, the water-based ink obtained by the production method is excellent in fixability, glossiness and image storage stability. Although the reason is not certain, it is considered that the amorphous polyester resin (A) has a structure in which the crystalline polyester resin (B) is finely dispersed, and is attributed to the structure. It is done.
Next, each step will be described.

[Step (1)]
In the step (1), the amorphous polyester (a1) having a non-aromatic carbon-carbon unsaturated bond having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower is mixed with the crystalline polyester resin (B), Next, the aqueous medium is mixed to obtain an aqueous dispersion of the resin mixture.
Thus, by mixing the amorphous polyester (a1) and the crystalline polyester resin (B) in advance, and then mixing the aqueous medium, the polyester resin particles in the obtained water-based ink become amorphous polyester-based. It is considered that the crystalline polyester resin (B) is finely dispersed in the resin (A), and the fixing property, glossiness, and image storability of the water-based ink are improved.
Next, a step of mixing the amorphous polyester (a1) and the crystalline polyester resin (B) to obtain a resin mixture (resin mixing step), and mixing an aqueous medium with the resin mixture to obtain an aqueous dispersion of the resin mixture The process of obtaining (the manufacturing process of an aqueous dispersion liquid) is demonstrated in this order.

<Resin mixing process>
The amorphous polyester (a1) and the crystalline polyester resin (B) are mixed by mixing the amorphous polyester (a1) and the crystalline polyester resin (B) with a surfactant in a ketone solvent as necessary. Then, it is preferably carried out by dissolving it into a mixed resin solution.
Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, methyl isobutyl ketone, and methyl isopropyl ketone. From the viewpoint of the solubility of the amorphous polyester (a1) and the crystalline polyester resin (B) and the ease of distilling off the solvent, methyl ethyl ketone is preferred.
The mixed resin solution may contain an aqueous medium to the extent that the continuous phase does not become an aqueous medium. As this aqueous medium, the aqueous medium used by the manufacturing process of the aqueous dispersion mentioned later is mentioned.

  The operation of dissolving the resin mixture in the ketone solvent is usually performed at a temperature below the boiling point of the ketone solvent. The temperature during the dissolving operation is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and still more preferably 70 from the viewpoint of sufficiently dissolving the amorphous polyester (a1) and the crystalline polyester resin (B) in the organic medium. It is 100 degreeC or less, More preferably, it is 90 degreeC or less, More preferably, it is 80 degreeC or less.

<Production process of aqueous dispersion>
By mixing an aqueous medium with the resin mixture obtained as described above, an aqueous dispersion of the resin mixture can be suitably obtained.
Here, the aqueous dispersion of the resin mixture refers to a dispersion whose continuous phase is an aqueous medium.
The aqueous medium is a medium containing water as a main component, that is, a medium having a water content of 50% by mass or more. From the viewpoint of environmental safety, the content of water in the aqueous medium is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably substantially 100% by mass. Examples of components other than water include organic solvents that dissolve in water, such as alcohol solvents such as methanol, ethanol, isopropanol, and butanol; ketone solvents such as acetone and methyl ethyl ketone; and ether solvents such as tetrahydrofuran.

  As a method of dispersing the resin mixture in the aqueous medium, a neutralizing agent described later is added to the resin mixture solution obtained in the resin mixture step to ionize the carboxy group of the resin mixture, and then water is added. A method of phase inversion to an aqueous system, preferably a method of adding water and then distilling off the ketone solvent to invert the phase to an aqueous system.

  In this step, as a method of adjusting the volume median particle size of the resin mixture particles in the aqueous dispersion of the resin mixture, the stirring force, the amount and type of the activator, the temperature, the amount and type of the neutralizer, the solvent The method etc. which adjust by changing one or more of quantity and kind are mentioned. Among these, since the particle diameter can be adjusted without affecting the resulting coating film, a method of adjusting by changing the stirring force is preferable.

More specifically, for example, a reactor equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas introduction pipe is prepared, and a neutralizer is added to the resin mixture dissolved in the ketone solvent. Then, the carboxy group is ionized (not required if already ionized), and then water is added to perform phase inversion to the aqueous system. Preferably, after adding water, the ketone solvent is distilled off to invert the phase to the aqueous system. .
The neutralizing agent is usually added at a temperature not higher than the boiling point of the ketone solvent. The temperature at the time of addition of the neutralizing agent is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 70 ° C. or higher, preferably 100 ° C. or lower, more preferably 90 ° C. or lower, still more preferably. It is 80 degrees C or less.
Examples of the water used include deionized water.

Examples of the neutralizing agent include aqueous alkaline solutions such as aqueous ammonia and sodium hydroxide, allylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine, triethylamine, 2-ethylhexylamine, tri-n-octylamine, t-butylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, n-propanolamine, butanolamine, 5-amino-4-octanol, monoethanolamine, N, N-dimethylethanolamine, isopropanolamine, neopen Examples include amines such as tanolamine, diglycolamine, ethylenediamine, and piperazine, preferably at least one of aqueous ammonia and sodium hydroxide. Preferably sodium hydroxide. The amount of the neutralizing agent used may be an amount that can at least neutralize the acid value of the resin mixture.
The volume-median particle size of the particles composed of the resin mixture in the aqueous dispersion obtained in the step (1) is preferably 0.05 μm or more from the viewpoint of improving ink ejection properties and image storage stability at high temperatures. More preferably, it is 0.10 micrometer or more, More preferably, it is 0.15 micrometer or more, More preferably, it is 0.20 micrometer or more. From the viewpoint of improving the initial fixability and fixing strength of the ink, it is preferably 0.30 μm or less, more preferably 0.25 μm or less, still more preferably 0.23 μm or less, and even more preferably 0.22 μm or less.

[Step (2)]
In the step (2), an addition-polymerizable monomer (a2) is added to the aqueous dispersion of the resin mixture obtained in the step (1) and polymerized to obtain a segment (A1 derived from the amorphous polyester (a1). ) And a segment (A2) derived from the addition polymerizable monomer (a2), the mass ratio of the graft polymer (AG) to the crystalline polyester resin (B) [ Graft polymer (AG) / crystalline polyester resin (B)] is 55/45 to 97/3, and an aqueous dispersion of polyester resin particles containing graft polymer (AG) and crystalline polyester resin (B) It is a process to obtain.
First, the addition polymerizable monomer (a2) is added to the aqueous dispersion of the resin mixture. The addition amount is a mass ratio of the polyester resin (a1) and the addition polymerizable monomer (a2) [polyester resin (a1) / addition polymerizable monomer (a2)], preferably 60/40 or more, more preferably 70/30 or more, more preferably 80/20 or more, more preferably 85/15 or more, and preferably 100/0 from the viewpoint of initial fixability and fixing strength of the ink on the recording medium. Or less, more preferably 95/5 or less.
Further, from the viewpoint of stirring efficiency, water or the like may be further added.

Next, the addition polymerizable monomer (a2) is polymerized in the presence of the resin mixture.
In the polymerization, a known radical polymerization initiator, a crosslinking agent and the like are added as necessary. As the radical polymerization initiator, a water-soluble radical polymerization initiator is preferably used, more preferably a persulfate salt, and still more preferably sodium persulfate.
The polymerization reaction is advanced by heating the mixed solution containing the resin mixture and the addition polymerizable monomer (a2). The polymerization temperature depends on the type of polymerization initiator used. For example, when sodium persulfate is used, it is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, from the viewpoint of efficiently performing the polymerization reaction. In addition, it is preferably 100 ° C. or lower, more preferably 90 ° C. or lower. From the same viewpoint, the reaction time is preferably 1 hour or longer, more preferably 3 hours or longer, and preferably 10 hours or shorter, more preferably 8 hours or shorter.

The solid content concentration of the aqueous dispersion of the polyester resin particles is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more, from the viewpoint of dispersibility and productivity of the resin particles. In addition, it is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less.
Further, the pH of the aqueous dispersion of polyester resin particles at 25 ° C. is preferably 5 to 10, more preferably 6 to 9, and still more preferably from the viewpoint of storage stability of the aqueous dispersion of polyester resin particles. 7-9.

[Step (3)]
In the step (3), the aqueous dispersion of the polyester resin particles obtained in the step (2), the aqueous dispersion containing the colorant, and the optional components described above are mixed as necessary. Next, the suitable example of a process (3) is demonstrated.
First, water such as ion-exchanged water and, if necessary, an optional organic solvent and at least one of various additives are mixed and stirred as necessary to obtain a mixed solution.
Next, this mixed solution is mixed with an aqueous dispersion containing a colorant, and further stirred and mixed while dropping the aqueous dispersion of the polyester resin particles obtained in the step (2). Thereafter, as necessary. A water-based ink can be suitably obtained by filtering with a filter or the like.

[3] Inkjet recording method In the inkjet recording method of the present invention, an aqueous ink containing a colorant and polyester resin particles is adhered to a hardly absorbent medium by an inkjet recording method, and then the hardly absorbent medium is heated to 70 ° C or higher. An inkjet recording method in which heating is performed at 150 ° C. or less, wherein the polyester resin particles have a glass transition temperature of 40 ° C. or more and 90 ° C. or less as a polyester resin constituting the polyester resin particles in one particle. The amorphous polyester resin (A) having an amorphous polyester portion and the crystalline polyester resin (B), and the amorphous to the crystalline polyester resin (B) in the aqueous ink Mass ratio of polyester resin (A) [amorphous polyester resin (A) / crystalline polyester resin ( B)] is an ink jet recording method in which 55/45 to 97/3.
The details of the water-based ink are the same as described above, and will be omitted.

In the ink jet recording method of the present invention, since the hardly absorbent medium is used as the recording medium, the initial fixing property and the fixing strength to the recording medium, which are the effects of the aqueous ink of the present invention, can be further exhibited.
The hardly absorbent medium in the present invention is a recording medium having a water absorption of 100 g / s to 0 g / m ^{2 to} 10 g / m ² , and examples thereof include coated paper and films.
The coated paper is preferably a coated paper for printing in which a coating layer is provided on the surface of a paper such as high-quality paper, and specifically, “OK Top Coat Plus” manufactured by Oji Paper Co., Ltd. and the like can be mentioned.

  If the heating temperature when heating the hardly absorbent medium with the water-based ink attached is 70 ° C. or more, the fixing property of the water-based ink to the hardly absorbent medium is excellent, and if it is 150 ° C. or less, the image Excellent storage stability. From this viewpoint, the heating temperature is preferably 75 ° C. or higher, more preferably 80 ° C. or higher, and preferably 100 ° C. or lower, more preferably 90 ° C. or lower.

  In relation to the above-described embodiment, the present invention discloses the following aqueous ink for inkjet recording, an inkjet recording method, and a method for producing an aqueous ink for inkjet recording.

<1> A water-based ink containing a colorant and polyester resin particles, wherein the polyester resin particles have a glass transition temperature of 40 ° C. or higher, preferably 50, as a polyester resin constituting the polyester resin particles. Amorphous polyester having a temperature of at least 0 ° C., more preferably at least 60 ° C., even more preferably at least 70 ° C., and at most 90 ° C., preferably at most 85 ° C., more preferably at most 80 ° C. The amorphous polyester resin (A) having a portion and the crystalline polyester resin (B), and the mass ratio of the amorphous polyester resin (A) to the crystalline polyester resin (B) [non- The crystalline polyester resin (A) / crystalline polyester resin (B)] is 55/45 or more, preferably 60/40 or more, more preferably 65/35 or more, more preferably 70/30 or more, and 97/3 or less, preferably 95/5 or less, more preferably 90/10 or less, and still more preferably 85/15 or less. Water-based ink for recording.

<2> The melting point of the crystalline polyester resin (B) is 50 ° C. or higher, preferably 60 ° C. or higher, more preferably 65 ° C. or higher, still more preferably 70 ° C. or higher, and 100 ° C. or lower, preferably The water-based ink for inkjet recording according to the above <1>, which is 90 ° C. or lower, more preferably 80 ° C. or lower, and further preferably 75 ° C. or lower.
<3> The crystalline polyester resin (B) comprises 70 mol% of an alcohol component containing 70 mol% or more of an α, ω-alkanediol having 8 to 14 carbon atoms and an aliphatic dicarboxylic acid having 4 to 14 carbon atoms. The water-based ink for inkjet recording according to the above <1> or <2>, which is obtained by condensation polymerization with the carboxylic acid component contained above.
<4> The acid value of the crystalline polyester resin (B) is preferably 1 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 15 mgKOH / g or more, still more preferably 20 mgKOH / g or more, Moreover, Preferably it is 35 mgKOH / g or less, More preferably, it is 30 mgKOH / g or less, More preferably, it is 25 mgKOH / g or less, More preferably, it is 23 mgKOH / g or less, Any one of said <1>-<3> Water-based ink for inkjet recording.
<5> The volume median particle size of the polyester resin particles is preferably 0.02 μm or more, more preferably 0.10 μm or more, more preferably 0.20 μm or more, and preferably 0.25 μm or less. The aqueous ink for inkjet recording according to any one of <1> to <4>, more preferably 0.24 μm or less, and still more preferably 0.23 μm or less.

<6> The above <1, wherein the amorphous polyester resin (A) is a graft polymer (AG) composed of a segment (A1) made of amorphous polyester and a segment (A2) made of an addition polymerization resin. The water-based ink for inkjet recording according to any one of> to <5>.
<7> The mass ratio [segment (A1) / segment (A2)] of the segment (A1) and the segment (A2) constituting the graft polymer (AG) is preferably 55/45 or more, more preferably 60/40. Or more, more preferably 65/35 or more, preferably 95/5 or less, more preferably 90/10 or less, still more preferably 85/15 or less, still more preferably 80/20 or less, The aqueous ink for inkjet recording according to the above <6>, further preferably 75/25 or less.
<8> The segment (A2) preferably contains 10% by mass or more of structural units derived from styrene, more preferably 30% by mass or more, still more preferably 40% by mass or more, and even more preferably 50% by mass or more. The aqueous system for ink jet recording according to <1> or <7>, preferably 100% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, and still more preferably 60% by mass or less. ink.
<9> Any of the above <6> to <8>, wherein the segment (A1) comprises a polyester obtained by condensation polymerization of an alcohol component containing 50 mol% or more of an alkylene oxide adduct of bisphenol A and a carboxylic acid component A water-based ink for ink jet recording according to any one of the above.

<10> A method for producing a water-based ink for inkjet recording, comprising the following steps (1) to (3).
Step (1): The amorphous polyester (a1) having a non-aromatic carbon-carbon unsaturated bond having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower is mixed with the crystalline polyester resin (B), and then Step of mixing aqueous medium to obtain aqueous dispersion of resin mixture Step (2): Adding addition polymerizable monomer (a2) to the aqueous dispersion of resin mixture obtained in step (1) and polymerizing The crystalline polyester is made of a graft polymer (AG) composed of a segment (A1) derived from the amorphous polyester (a1) and a segment (A2) derived from the addition polymerizable monomer (a2). Graft having a mass ratio [graft polymer (AG) / crystalline polyester resin (B)] of the graft polymer (AG) to the resin (B) of 55/45 to 97/3 Step of obtaining an aqueous dispersion of polymer (AG) and crystalline polyester resin (B) Step (3): An aqueous dispersion of polyester resin particles obtained in step (2), and an aqueous dispersion containing a colorant Step 11 of obtaining a water-based ink for ink jet recording <11> An amorphous polyester resin (a1) having a non-aromatic carbon-carbon unsaturated bond is formed of an unsaturated aliphatic carboxylic acid and an unsaturated alicyclic ring. Manufacture of the aqueous ink for inkjet recording as described in said <10> obtained by polycondensing the alcohol component and carboxylic acid component which contain 3 mol% or more and 30 mol% or less of at least 1 type carboxylic acid Method.

<12> An inkjet recording method in which a water-based ink containing a colorant and polyester resin particles is attached to a hardly absorbent medium by an inkjet recording method, and then the hardly absorbent medium is heated at 70 ° C. or higher and 150 ° C. or lower. The polyester-based resin particle is an amorphous resin having an amorphous polyester portion having a glass transition temperature of 40 ° C. or more and 90 ° C. or less as a polyester-based resin constituting the polyester-based resin particle in one particle. A polyester resin (A) and a crystalline polyester resin (B) are contained, and the mass ratio of the amorphous polyester resin (A) to the crystalline polyester resin (B) in the water-based ink [non- The crystalline polyester resin (A) / crystalline polyester resin (B)] is 55/45 to 97/3. Method.

  Hereinafter, the present invention will be described more specifically with reference to examples and the like. In the following examples and the like, each physical property was measured by the following method. “Parts” and “%” are “parts by mass” and “% by mass” unless otherwise specified.

[Acid value of resin]
The measurement solvent was measured according to JIS K0070, except that the mixed solvent of ethanol and ether was changed to a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Softening point of resin]
Using a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C./min, a load of 1.96 MPa was applied by a plunger, a diameter of 1 mm, and a length of 1 mm. Extruded from the nozzle. The amount of plunger drop of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

[Melting point of resin, glass transition temperature and crystallinity index]
Using a differential scanning calorimeter “Q-100” manufactured by T.A. Instrument Japan, 0.01 to 0.02 g of a sample was weighed into an aluminum pan, heated to 200 ° C., and from that temperature A sample for measurement was prepared by cooling to 0 ° C. at a temperature drop rate of 10 ° C./min. Thereafter, the temperature is increased at a rate of temperature increase of 10 ° C./min, the endothermic maximum peak temperature is taken as the melting point, and the maximum slope from the peak rising portion to the peak apex is shown below the maximum endothermic peak temperature. The temperature at the intersection with the tangent line was defined as the glass transition temperature. Further, the crystallinity index is obtained from the softening point (° C.) / (Maximum endothermic peak temperature (° C.)), the crystallinity index is 0.6 to 1.4, and the others are amorphous. It was.
In the case of resin particles in an aqueous dispersion of resin particles, the aqueous dispersion was freeze-dried at −10 ° C. for 9 hours using a freeze dryer “FDU-2100” manufactured by Tokyo Rika Kikai Co., Ltd. A sample was used.

[Number average molecular weight of resin]
The molecular weight distribution was measured by gel permeation chromatography and the number average molecular weight was calculated by the following method.
(1) Preparation of sample solution The resin was dissolved in chloroform so that the concentration was 0.5 g / 100 ml. Next, this solution was filtered using a fluororesin filter “FP-200” manufactured by Sumitomo Electric Industries, Ltd. having a pore size of 2 μm to remove insoluble components to obtain a sample solution.
(2) Molecular weight measurement Tetrahydrofuran was flowed as a dissolution liquid at a flow rate of 1 ml / min, and the column was stabilized in a constant temperature bath at 40 ° C. Measurement was performed by injecting 100 μl of the sample solution. The number average molecular weight of the sample was calculated based on a calibration curve prepared in advance. The calibration curves are several types of monodisperse polystyrene (monodisperse polystyrene manufactured by Tosoh Corporation; 2.63 × 10 ³ , 2.06 × 10 ⁴ , 1.02 × 10 ⁵ (weight average molecular weight), manufactured by GL Sciences Inc. Of monodisperse polystyrene; 2.10 × 10 ³ , 7.00 × 10 ³ , 5.04 × 10 ⁴ (weight average molecular weight)) were used as standard samples.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analysis column: GMHXL + G3000HXL (manufactured by Tosoh Corporation)

[Volume Median Particle Size (D ₅₀ ) of Resin Particles in Aqueous Dispersion]
The volume-median particle size (D ₅₀ ) was measured under the following conditions using a dynamic light scattering particle size measuring device “ZETASIZER NANO ZS” manufactured by Malvern.
Solid content concentration: 0.1% by mass
Measurement temperature: 25 ° C
Medium: Water Measurement cell: Glass Cuvette
Laser specification: He-Ne, 4mW, 633nm
Detection optical system: NIBS, 173 ° C.
Number of measurements: 10 times Isothermal time: 5 minutes Analysis software: Zeta Sizer Software 6.2
Analysis method: General Purpose Mode (cumulant method)

[Solid content concentration of aqueous dispersion]
Using an infrared moisture meter “FD-230” manufactured by Kett Science Laboratory, 5 g of an aqueous dispersion was measured at a drying temperature of 150 ° C. and in a measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%). The water dispersion (mass%) of the aqueous dispersion was measured. The solid content concentration was calculated according to the following formula.
Solid content concentration (% by mass) = 100-M
M: moisture (mass%) of the aqueous dispersion = [(W−W ₀ ) / W] × 100
W: Sample mass before measurement (initial sample mass)
W ₀ : Mass of sample after measurement (absolute dry mass)

[Measurement of weight average molecular weight of water-insoluble polymer (anionic polymer)]
Using a solution obtained by dissolving phosphoric acid and lithium bromide in N, N-dimethylformamide so as to have concentrations of 60 mmol / L and 50 mmol / L, respectively, using gel permeation chromatography and polystyrene as a standard substance. The measurement was performed under the following conditions.
GPC device: “HLC-8120GPC” manufactured by Tosoh Corporation
Column: “TSK-GEL, α-M”, manufactured by Tosoh Corporation, 2 Flow rate: 1 mL / min

[Measurement of solid content concentration of aqueous dispersion of pigment-containing water-insoluble polymer particles (anionic polymer particles)]
Weigh out 10.0 g of sodium sulfate constant in a desiccator into a 30 mL ointment container, add approximately 1.0 g of the sample to it, mix, then weigh accurately and maintain at 105 ° C. for 2 hours. The volatile matter was removed, and the sample was further left for 15 minutes in a desiccator, and the mass was measured. The mass of the sample after removal of the volatile matter was taken as the solid content and divided by the mass of the added sample to obtain the solid content concentration.

[Measurement of average particle size of water-insoluble polymer particles (anionic polymer particles) containing pigment]
Measurement was performed using a laser particle analysis system “ELS-8000” (cumulant analysis) manufactured by Otsuka Electronics Co., Ltd. A dispersion diluted with water so that the concentration of particles to be measured was about 5 × 10 ⁻³ mass% was used. The measurement conditions were a temperature of 25 ° C., an angle between incident light and a detector of 90 °, and the number of integrations of 100. The refractive index of water (1.333) was input as the refractive index of the dispersion solvent.

[Water absorption amount of recording medium in 100 milliseconds]
Using an automatic scanning absorption meter “KM500win” manufactured by Kumagai Riki Kogyo Co., Ltd., the amount of transition at a contact time of 100 msec of pure water was measured at 23 ° C. and a relative humidity of 50%. It was set as the amount of water absorption.

(1) Evaluation of Fixability The ink was filled into the ink injection port on the upper part of the cyan head of an ink jet printer “IPSiO GX 5000” manufactured by Ricoh Co., Ltd. via a silicon tube.
Create a solid print pattern (size: 204 mm wide x 275 mm long) with Adobe Photoshop and apply coated paper “OK Top” by Oji Paper Co., Ltd. so that the discharge amount is 14 ± 2 g / m ^2. coat plus "(water absorption amount at a basis weight 104.7 g / m ^2, 100 m sec 4.9 g / m ²⁾ was printed, after placing 5 seconds on a hot plate of 80 ° C., cooled at 25 ° C., Asahi Kasei A cellulose non-woven fabric “Bencot M3-II” manufactured by Sensui Co., Ltd. was rubbed 5 times with a load of 2 kg. The image density of the cellulose nonwoven fabric surface before and after rubbing was measured using a reflection densitometer “RD-915” manufactured by Gretag Macbeth. The difference in image density before and after rubbing was calculated, and the initial fixability was evaluated using the calculated value. The smaller the value, the better the fixing property.

(2) Evaluation of Glossiness The ink was filled into the ink injection port on the upper part of the cyan head of an ink jet printer “IPSiO GX 5000” manufactured by Ricoh Co., Ltd. via a silicon tube.
Create a solid print pattern (size: 204 mm wide x 275 mm long) with Adobe Photoshop and apply coated paper “OK Top” by Oji Paper Co., Ltd. so that the discharge amount is 14 ± 2 g / m ^2. coat plus "(water absorption amount at a basis weight 104.7 g / m ^2, 100 m sec 4.9 g / m ²⁾ was printed, after placing 5 minutes prints on a hot plate at 90 ° C., cooled at 25 ° C. The gloss of the solid print pattern was measured using a gloss meter “IG-330” manufactured by HORIBA under 20 ° light conditions. The higher the value obtained, the higher the glossiness.

(3) Evaluation of image storability The ink was filled into the ink injection port on the upper part of the cyan head of an inkjet printer “IPSiO GX 5000” manufactured by Ricoh Co., Ltd. via a silicon tube.
Create a solid print pattern (size: 204 mm wide x 275 mm long) with Adobe Photoshop and apply coated paper “OK Top” by Oji Paper Co., Ltd. so that the discharge amount is 14 ± 2 g / m ^2. coat plus "(water absorption amount at a basis weight 104.7 g / m ^2, 100 m sec 4.9 g / m ²⁾ was printed, after placing 5 minutes prints on a hot plate at 90 ° C., cooled at 25 ° C. Then, 500 copies of Fuji Xerox copy paper “J paper” were placed on the printed matter, and a weight of 2 kg was further placed thereon, and stored in a high temperature and humidity chamber at 50 ° C. and 60 RH% for 3 days. After storage, the printed matter and J paper were peeled off and evaluated according to the following criteria.
A: There was no adhesion between the printed matter and J paper.
B: Although there was adhesion between the printed matter and J paper, it was peeled off without damaging the printed pattern.
C: There was adhesion between the printed matter and J paper, and after peeling, there was slight coloring on the J paper, but damage to the printing pattern could not be confirmed.
D: There was adhesion between the printed matter and J paper, and the print pattern was damaged.

Production Examples 1-10
(Manufacture of amorphous polyester resin P1-10)
The alcohol component excluding fumaric acid shown in Table 1, the acid component, 20 g of tin octylate, and 1 g of gallic acid are placed in a 10 L four-necked flask equipped with a thermometer, stirrer, flow-down condenser, and nitrogen inlet tube. After heating up to 180 ° C. in a mantle heater in a nitrogen atmosphere, the temperature was raised to 230 ° C. over 5 hours. Then, after reacting at 230 degreeC for 5 hours, it cooled to 180 degreeC and added the fumaric acid. After heating up to 200 degreeC over 3 hours, it was made to react at 200 degreeC and 8 kPa until the softening point measured according to ASTMD36-86 reached the temperature shown in a table | surface, and amorphous polyester resin was obtained.
Table 1 shows the types and blending amounts of the alcohol component and acid component used as raw materials, the physical properties of the obtained polyester resin, and the like.

Production Examples 11 to 16
(Production of crystalline polyester resin C1-6)
An alcohol component and an acid component shown in Table 2 were charged into a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, heated to 140 ° C., and reacted for 4 hours. Thereafter, the reaction was carried out to 200 ° C. over 10 hours, and the reaction was carried out at 8.3 kPa for 30 minutes. After returning to atmospheric pressure, 30 g of titanium diisopropylate bistriethanolamate and 3 g of gallic acid monohydrate were added and reacted at normal pressure for 30 minutes, and then reacted at 8.3 kPa for 1 hour to obtain a polyester resin. It was.
Table 2 shows the types and blending amounts of the alcohol component and acid component used as raw materials, the physical properties of the obtained polyester resin, and the like.

Production Examples 17 to 39
(Production of aqueous dispersions E1 to E23 containing a resin mixture)
In a 2000 mL SUS304 separable flask, an amorphous polyester resin that is a component derived from the segment (A1) of the crystalline polyester resin (B) and the amorphous polyester resin (A) shown in Table 3 under stirring conditions. a1) in total 200 g, anionic surfactant (sodium dodecylbenzenesulfonate) “Neopelex G-15” manufactured by Kao Corporation 3 g in solid conversion and 200 g methyl ethyl ketone were mixed and dissolved at 70 ° C. I let you. The mixture was neutralized by adding 1.58 g of 48% sodium hydroxide. Thereafter, 467 g of ion exchange water was added and mixed. Further, methyl ethyl ketone was distilled off under reduced pressure. Thereafter, the solid content was adjusted to 30% by mass with ion-exchanged water to obtain an aqueous dispersion containing a resin mixture. The measurement results of the volume median particle size are shown in Table 3.

Production Examples 40 to 66
(Production of aqueous dispersions G1 to G27 containing polyester resin particles)
A four-necked flask with an internal volume of 2 liters equipped with a nitrogen inlet tube, a reflux condenser, a dropping funnel, a stirrer, and a thermocouple, an aqueous dispersion containing a polyester resin of the types and amounts shown in Tables 4 and 5, a segment ( As monomers for forming A2), styrene and 2-ethylhexyl acrylate (2EHA), which are addition polymerizable monomers in amounts shown in Tables 4 and 5, were charged and stirred for 30 minutes. Next, under the nitrogen stream, the amount of sodium persulfate shown in Tables 4 and 5 was added and reacted at 80 ° C. for 6 hours. Thereafter, the remaining addition polymerizable monomer under reduced pressure was removed together with water. The mixture was cooled to room temperature, filtered through a 200-mesh wire mesh, adjusted to 30% by mass with ion-exchanged water, and an aqueous dispersion containing polyester resin particles was obtained.
However, in Production Example 66, the aqueous dispersion E4 containing the polyester resin was used as it was as the aqueous dispersion G27 containing the polyester resin particles.
The physical properties and the like of the obtained aqueous dispersion are shown in Tables 4 and 5.

Production Example 67 (Preparation of aqueous dispersion of pigment-containing insoluble polymer particles)
(1) Synthesis of water-insoluble polymer (anionic polymer) 399 parts of benzyl methacrylate manufactured by Wako Pure Chemical Industries, Ltd. 91 parts of methacrylic acid manufactured by Wako Pure Chemical Industries, Ltd., methoxypolyethylene glycol manufactured by Shin-Nakamura Chemical Co., Ltd. 140 parts of methacrylate “M-230G” (average number of moles of oxyethylene group added: 23) and 140 parts of styrene macromer “AS-6S” (solid content: 50%) manufactured by Toagosei Co., Ltd. are mixed, and 770 parts of monomer mixture Was prepared. In a reaction vessel, 15.75 parts of methyl ethyl ketone, 0.35 part of a polymerization chain transfer agent (2-mercaptoethanol) and 10% (77 parts) of the monomer mixture were mixed and subjected to nitrogen gas replacement.
Meanwhile, 80% (616 parts) of the monomer mixture, 2.45 parts of the polymerization chain transfer agent, 173.25 parts of methyl ethyl ketone, and a polymerization initiator “V-65” manufactured by Wako Pure Chemical Industries, Ltd. A mixture of 5.6 parts of 2,2′-azobis (2,4-dimethylvaleronitrile)) was added, and the mixture was heated to 75 ° C. in a nitrogen atmosphere while stirring the mixed solution in the reaction vessel. The mixed solution was added dropwise over 4.5 hours. Thereafter, the remaining 10% (77 parts) of the monomer mixture, 0.7 part of the polymerization chain transfer agent, 126 parts of methyl ethyl ketone and 1.4 part of the polymerization initiator were mixed at 75 ° C. for 1.7 hours. It was dripped. After completion of dropping, 2.1 parts of the polymerization initiator was mixed, heated to 80 ° C., and stirred for 1.5 hours. The polymer solution (polymer weight average molecular weight: 26,000) was obtained by further mixing the polymerization initiator, raising the temperature, and stirring operations twice.

(2) Preparation of aqueous dispersion of pigment-containing water-insoluble polymer particles (pigment-containing anionic polymer particles) 202.8 parts of the polymer obtained by drying the polymer solution obtained in (1) above under reduced pressure was 62.8 parts of methyl ethyl ketone. Into this, 5.01 parts of a neutralizing agent 5N aqueous sodium hydroxide solution, 1.13 parts of 25% aqueous ammonia and 236.5 parts of ion-exchanged water were added, and 2000 rpm using a disper blade at 10 to 15 ° C. And stirred for 15 minutes. Subsequently, 45 parts of PV19 “Inkjet Magenta E5B02” manufactured by Clariant Co., Ltd. and 25 parts of PR122 “6111T” manufactured by Dainichi Seika Kogyo Co., Ltd. were added as magenta pigments, and stirred at 7000 rpm for 3 hours at 10 to 15 ° C. using a disperse blade. Mixed. The obtained dispersion was filtered through 200 mesh and subjected to a 20-pass dispersion treatment at a pressure of 150 MPa using a microfluidizer “M-110K” (high pressure homogenizer) manufactured by Microfluidics.
Methyl ethyl ketone is removed from the obtained dispersion at 60 ° C. under reduced pressure, a part of water is further removed, the mixture is centrifuged, and the liquid layer is filtered through a filter with a pore size of 5 μm manufactured by Sartorius Stedim Biotech. Was excluded. Further, 80 parts of this dispersion was mixed with 5.0 parts of glycerin manufactured by Kao Corporation, 0.2 part of 1,2-benzisothiazol-3 (2h) -one “Proxel XL2” manufactured by Avicia Co., Ltd., and ion-exchanged water 14 .8 parts are mixed, sterilized at 70 ° C. for 1 hour, cooled to room temperature, and filtered through a filter having a pore size of 5 μm, so that water-insoluble polymer particles (anionic polymer particles) containing pigment are contained. An aqueous dispersion (solid content concentration 20%, average particle size 133 nm) was obtained.

Example 1 (Production of water-based ink)
8.67 parts of glycerin manufactured by Kao Corporation, 15.0 parts of diethylene glycol manufactured by Wako Pure Chemical Industries, Ltd., wetting agent “Surfinol 104PG50” manufactured by Nissin Chemical Industry Co., Ltd. (active ingredients: acetylene glycol, wetting agent) 1.50 parts, 1.50 parts of an emulsifier “Emulgen 120” (polyoxyethylene lauryl ether) manufactured by Kao Corporation and 29.96 parts of ion-exchanged water are mixed and stirred with a magnetic stirrer at room temperature for 15 minutes. A mixed solution was obtained.
Next, while stirring 26.67 parts of an aqueous dispersion of anionic polymer particles containing the pigment obtained in Production Example 67 (4.0 parts in terms of pigment content in 100 parts of water-based ink) with a magnetic stirrer, The mixed solution was mixed, and further, 16.7 parts of an aqueous dispersion containing polyester resin particles shown in Table 6 (8.0 parts in terms of solid content in 100 parts of water-based ink) was stirred and mixed while dropping with a dropper. Finally, it was filtered with a fluororesin filter “FP-200” manufactured by Sumitomo Electric Industries, Ltd. having a pore size of 2 μm to obtain a water-based ink. Table 6 shows the evaluation results of the obtained water-based ink.

Examples 2-27 and Comparative Examples 1-5 (Production of water-based ink)
In Examples 2 to 27 and Comparative Examples 1 to 5, the same operation as in Example 1 was performed except that the type and addition amount of the aqueous dispersion containing polyester resin particles were as shown in Table 6. Ink was obtained.
In Comparative Example 4, a water-based ink was obtained in the same manner as in Example 1 except that the aqueous dispersion containing polyester-based resin particles was not added.
Table 6 shows the evaluation results of the obtained water-based ink.

  From the results of Table 6, it can be seen that the water-based inks of the examples are superior in fixing property, gloss of printed matter, and image storability as compared with the water-based inks of the comparative examples.

Claims (12)

A water-based ink containing a colorant and polyester resin particles,
The polyester resin particles are amorphous polyester resins (A) having an amorphous polyester portion having a glass transition temperature of 40 ° C. or more and 90 ° C. or less as a polyester resin constituting the polyester resin particles; A crystalline polyester resin (B),
The mass ratio of the amorphous polyester resin (A) to the crystalline polyester resin (B) [amorphous polyester resin (A) / crystalline polyester resin (B)] is 55/45 to 97/3. A water-based ink for inkjet recording.   The water-based ink for inkjet recording according to claim 1, wherein the crystalline polyester resin (B) has a melting point of 50 ° C. or higher and 100 ° C. or lower.   The crystalline polyester resin (B) contains an alcohol component containing 70 mol% or more of an α, ω-alkanediol having 8 to 14 carbon atoms and 70 mol% or more of an aliphatic dicarboxylic acid having 4 to 14 carbon atoms. The water-based ink for inkjet recording according to claim 1, which is obtained by condensation polymerization with a carboxylic acid component.   The water-based ink for inkjet recording according to any one of claims 1 to 3, wherein the acid value of the crystalline polyester resin (B) is 1 mgKOH / g or more and 35 mgKOH / g or less.   The water-based ink for inkjet recording according to any one of claims 1 to 4, wherein the polyester resin particles have a volume-median particle size of 20 nm or more and 250 nm or less.   The amorphous polyester resin (A) is a graft polymer (AG) composed of a segment (A1) made of amorphous polyester and a segment (A2) made of an addition polymerization resin. The water-based ink for inkjet recording according to any one of the above.   The mass ratio [segment (A1) / segment (A2)] of the segment (A1) and the segment (A2) constituting the graft polymer (AG) is 55/45 to 95/5. Water-based ink for inkjet recording.   The water-based ink for inkjet recording according to claim 6 or 7, wherein the segment (A2) contains a structural unit derived from styrene in an amount of 10% by mass to 100% by mass.   The inkjet recording according to any one of claims 6 to 8, wherein the segment (A1) comprises a polyester obtained by condensation polymerization of an alcohol component containing 50 mol% or more of an alkylene oxide adduct of bisphenol A and a carboxylic acid component. Water-based ink. The manufacturing method of the water-based ink for inkjet recording which has following process (1)-(3).
Step (1): The amorphous polyester (a1) having a non-aromatic carbon-carbon unsaturated bond having a glass transition temperature of 40 ° C. or higher and 90 ° C. or lower is mixed with the crystalline polyester resin (B), and then Step of mixing aqueous medium to obtain aqueous dispersion of resin mixture Step (2): Adding addition polymerizable monomer (a2) to the aqueous dispersion of resin mixture obtained in step (1) and polymerizing The crystalline polyester is made of a graft polymer (AG) composed of a segment (A1) derived from the amorphous polyester (a1) and a segment (A2) derived from the addition polymerizable monomer (a2). Graph wherein mass ratio of graft polymer (AG) to resin (B) [graft polymer (AG) / crystalline polyester resin (B)] is 55/45 to 97/3 Step of obtaining an aqueous dispersion of polyester resin particles containing a polymer (AG) and a crystalline polyester resin (B) Step (3): An aqueous dispersion of polyester resin particles obtained in step (2), and coloring Mixing with an aqueous dispersion containing an agent to obtain an aqueous ink for inkjet recording   The amorphous polyester resin (a1) having a non-aromatic carbon-carbon unsaturated bond contains 3 mol% or more and 30 mol% or less of at least one of an unsaturated aliphatic carboxylic acid and an unsaturated alicyclic carboxylic acid. The method for producing a water-based ink for ink-jet recording according to claim 10, which is obtained by condensation polymerization of an alcohol component and a carboxylic acid component. An ink jet recording method in which a water-based ink containing a colorant and polyester resin particles is attached to a hardly absorbent medium by an ink jet recording method, and then the hardly absorbent medium is heated at 70 ° C. or higher and 150 ° C. or lower.
The polyester resin particles are amorphous polyester resins having an amorphous polyester portion having a glass transition temperature of 40 ° C. or more and 90 ° C. or less as a polyester resin constituting the polyester resin particles in one particle. (A) and crystalline polyester resin (B) are contained,
The mass ratio of the amorphous polyester resin (A) to the crystalline polyester resin (B) in the water-based ink [amorphous polyester resin (A) / crystalline polyester resin (B)] is 55. An ink jet recording method of / 45 to 97/3.