JP2017203077A - Ink composition and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition having excellent rubbing resistance and suppressing bleeding in a recorded matter while maintaining excellent discharge stability, when a coagulation liquid and the ink composition are deposited on a recording medium.SOLUTION: The ink composition comprises water and polymer particles, in which the polymer particles have a core-shell structure comprising a core polymer and a shell polymer, and the shell polymer has an acid value higher than that of the core polymer. The composition contains an organic solvent having a standard boiling point of 280°C or higher by 5 mass% or less with respect to the total mass of the ink composition. The ink composition is used for a recording method using the ink composition and a coagulation liquid containing a coagulant that can coagulate or thicken a component of the ink composition.SELECTED DRAWING: None

Description

  The present invention relates to an ink composition and a recording method.

  The ink jet recording method is capable of recording high-definition images with a relatively simple device, and has been rapidly developed in various fields. Among them, various studies have been made on obtaining a more stable and high-quality recorded matter.

  For example, Patent Document 1 discloses an ink jet ink, which is excellent in ink drying property at the time of high-speed printing and is excellent in ink storage stability. It is for use with a reaction solution for curing, and includes water, a water-soluble organic solvent, a colorant, and a binder resin. The binder resin is composed of a core portion and a shell portion that covers the core portion. Ink-jet ink is disclosed, which has a reactive group that reacts with the reaction liquid on the surface, and has an MFT in the shell portion higher than the MFT in the core portion.

JP2013-204025A

  The ink composition as disclosed in Patent Document 1 is used together with the reaction liquid, but by including a specific binder resin, a certain degree of drying property of the ink composition can be obtained. Moreover, this ink composition is excellent also in discharge stability by containing a specific binder resin. However, such an ink composition does not have sufficient abrasion resistance due to the high acid value of the specific binder resin. Further, even if the acid value of the specific binder resin is lowered, bleeding may occur in the obtained recorded matter due to insufficient reactivity of the specific binder resin with respect to the reaction solution.

  Therefore, the present invention has been made to solve the above-described problems, and is excellent in abrasion resistance and suppresses bleeding of recorded matter when an aggregating liquid and an ink composition are adhered to a recording medium. It is an object of the present invention to provide an ink composition.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have a core-shell structure including water and polymer particles, and the polymer particles each include a core polymer and a shell polymer. An ink composition having an acid value higher than the acid value of the core polymer and having a standard boiling point of 280 ° C. or higher and an organic solvent content of 5% by mass or less is agglomerated between the ink composition and the components of the ink composition. Alternatively, the present invention has been completed by finding that it is excellent in ejection stability, abrasion resistance and image quality by using a recording method for recording using an aggregating liquid containing an aggregating agent capable of increasing viscosity. .

  That is, the present invention is an ink composition comprising water and polymer particles, wherein the polymer particles have a core-shell structure including a core polymer and a shell polymer, and the acid value of the shell polymer is The content of the organic solvent which is higher than the acid value of the core polymer and has a standard boiling point of 280 ° C. or more is 5% by mass or less based on the total mass of the ink composition, and the ink composition and the ink composition And an aggregating liquid containing an aggregating agent capable of aggregating or thickening the components of the ink composition. The reason why such an ink composition can solve the problems of the present invention is considered as follows. However, the factor is not limited to this. That is, the ink composition according to the present invention is used in a recording method for recording using the ink composition and the aggregation liquid by including polymer particles in which the acid value of the shell polymer is higher than the acid value of the core polymer. In this case, the reactivity between the polymer particles and the agglomerated liquid can be maintained, and the acid value of the entire polymer particles can be made lower than the acid value of the shell polymer. Further, when the content of the organic solvent having a normal boiling point of 280 ° C. or higher is 5% by mass or less, the drying property is excellent, and the bleeding of the recorded matter is excellent and the abrasion resistance is excellent. As a result, the ink composition according to the present invention can maintain excellent abrasion resistance, suppress bleeding of recorded matter, and have excellent image quality.

  In the ink composition according to the present invention, the acid value of the shell polymer is at least 20 mgKOH / g, and the acid value of the core polymer is at least 15 mgKOH / g. Preferably, the recording method preferably includes an ink composition attaching step in which the ink composition is attached to a recording medium having a surface temperature of 30 ° C. or more, and the ink composition and the aggregation liquid are attached. It is also preferable to further include a step of heating the recording medium to 40 ° C. or more, and the content of the polymer particles is preferably 1.0% by mass or more based on the total amount of the ink composition, The glass transition temperature of the shell polymer is not less than the glass transition temperature of the core polymer, and the surface temperature is not less than the glass transition temperature of the shell polymer. Preferably, the shell polymer contains at least an aromatic monomer unit as a constituent unit, and the content of the aromatic monomer unit is 10% by mass or more based on the total amount of the constituent units contained in the shell polymer. Preferably, the aggregating agent is preferably one or more selected from the group consisting of a polyvalent metal salt, an organic acid, and a cationic compound, and the average particle size of the polymer particles is from 20 nm to 400 nm. Preferably, the organic solvent further includes an organic solvent, and the organic solvent preferably includes an organic solvent having a standard boiling point of 150 ° C. or higher and 250 ° C. or lower.

  Furthermore, the recording method according to the present invention includes an aggregation liquid adhesion step in which an aggregation liquid containing an aggregating agent capable of aggregating or thickening the components of the ink composition is adhered to a recording medium; and the ink composition An ink composition adhering step for adhering the ink to a recording medium.

1 is a side view showing an outline of an example of an inkjet recording apparatus that can be used in the present embodiment.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to this, and the gist thereof is described below. Various modifications are possible without departing from the scope. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, positional relationships such as up, down, left and right are based on the positional relationships shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[Ink composition]
The ink composition of the present embodiment includes water and polymer particles, and recording is performed using the ink composition and an aggregating liquid containing an aggregating agent capable of aggregating or thickening the components of the ink composition. Used for recording method. The polymer particles have a core-shell structure including a core polymer and a shell polymer, and the acid value of the shell polymer is higher than the acid value of the core polymer. Furthermore, the content of the organic solvent having a standard boiling point of 280 ° C. or higher is 5% by mass or less with respect to the total mass (100% by mass) of the ink composition. By using such an ink composition in a recording method for recording using the ink composition and an aggregating liquid containing an aggregating agent capable of aggregating or thickening the components of the ink composition, the ink composition can be obtained. This improves the abrasion resistance and image quality (bleeding suppression) of the recorded material. The ink composition of the present embodiment is excellent in glossiness, image quality (color development), clogging suppression, and ejection stability, in addition to excellent abrasion resistance and image quality (bleed suppression).

<Color material>
The ink composition of the present embodiment may be a colored ink composition further containing a color material, or may be a clear ink composition substantially free of a color material. A pigment can be used as the color material. Although it does not specifically limit as a pigment, For example, the following are mentioned.

  The carbon black used for the black ink is not particularly limited. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B, etc. (Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (above, Columbia Carbon, Carbon 1 Rubbi 400, Carbon Co. Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (Cabot Corp. CA Kol. , Color B lack FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Special Black 5, Special Black 4A , Special Black 4 (manufactured by Degussa).

  Although it does not specifically limit as a pigment used for white ink, For example, C.I. I. Pigment white 6, 18, 21, titanium oxide, zinc oxide, zinc sulfide, antimony oxide, zirconium oxide, white hollow resin particles and polymer particles.

  Although it does not specifically limit as a pigment used for yellow ink, For example, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 167, 172, 180.

  Although it does not specifically limit as a pigment used for a magenta ink, For example, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48: 2, 48: 5, 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, or C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50.

  Although it does not specifically limit as a pigment used for cyan ink, For example, C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25, 60, 65, 66, C.I. I. Bat Blue 4, 60.

  The pigments other than those described above are not particularly limited. I. Pigment green 7,10, C.I. I. Pigment brown 3, 5, 25, 26, C.I. I. Pigment orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, 63.

  The color material preferably contains one or more pigments selected from the group consisting of self-dispersing pigments and polymer-dispersed pigments. Thereby, the color material tends to be more excellent in glossiness due to the uniform dispersion in the recorded matter.

The self-dispersing pigment is a pigment having a hydrophilic group on its surface. As the hydrophilic group, -OM, -COOM, -CO -, - SO 3 M, -SO 2 M, -SO 2 NH 2, -RSO 2 M, -PO 3 HM, -PO 3 M 2, -SO 2 It is preferably at least one hydrophilic group selected from the group consisting of NHCOR, —NH ₃ , and —NR ₃ .

  In these chemical formulas, M represents a hydrogen atom, an alkali metal, ammonium, an optionally substituted phenyl group, or organic ammonium, and R represents an alkyl group having 1 to 12 carbon atoms or a substituted group. A naphthyl group which may have a group is represented. The above M and R are selected independently of each other.

  Specifically, the self-dispersing pigment is produced by subjecting the pigment to physical treatment and / or chemical treatment to bond (graft) the hydrophilic group to the surface of the pigment. Specific examples of the physical treatment include vacuum plasma treatment. Further, as the chemical treatment, specifically, a wet oxidation method in which oxidation is performed with an oxidizing agent in water, a method in which p-aminobenzoic acid is bonded to the pigment surface to bond a carboxyl group via a phenyl group, and the like can be mentioned. It is done.

  The polymer-dispersed pigment is a pigment that can be dispersed in a liquid by a polymer. The polymer content relative to the pigment can be expressed as the coverage of the polymer that coats the pigment. The polymer coverage is preferably 1.0% to 50%, more preferably 1.0% to 10%, and still more preferably 1.0% to 5.0%. When the coverage is 1.0% or more, the dispersibility tends to be good. Further, when the coverage is 50% or less, the color developability tends to be further improved, and when it is 5.0% or less, the color developability tends to be even better. is there.

  70 mass% or more of the said polymer is preferable in it being a polymer by the copolymerization of (meth) acrylate and (meth) acrylic acid among the structural components. Thereby, it tends to be further excellent in the fixing property and glossiness of the ink. Moreover, it is more preferable that at least one of the alkyl (meth) acrylate having 1 to 24 carbon atoms and the cyclic alkyl (meth) acrylate having 3 to 24 carbon atoms is polymerized from a monomer component of 70% by mass or more. Specifically, as the monomer component, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate Cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetramethylpiperidyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dis Ropenteniru (meth) acrylate, dicyclopentenyloxy (meth) acrylate, and behenyl (meth) acrylate. In addition, as other monomer components for polymerization, hydroxy (meth) acrylate having a hydroxyl group such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, diethylene glycol (meth) acrylate, urethane (meth) acrylate, epoxy (meth) ) Acrylate and the like. In the present specification, “(meth) acrylate” is a concept including both “methacrylate” and “acrylate”.

  In the ink composition, the content of the coloring material is preferably 0.2% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less with respect to the total amount (100% by mass) of the ink composition. It is 0.0 mass% or less, More preferably, it is 1.0 mass% or more and 3.0 mass% or less. When the content of the color material is within the above range, the color developability tends to be further improved.

<Water>
Examples of the water in this embodiment include water from which ionic impurities are removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. . In addition, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the aggregated liquid is stored for a long period of time. This tends to improve the storage stability.

<Organic solvent>
The ink composition of this embodiment preferably further contains an organic solvent. The organic solvent of the present embodiment more preferably includes an organic solvent having a normal boiling point of 150 ° C. or higher and 250 ° C. or lower. In the ink composition of the present embodiment, the content of an organic solvent having a standard boiling point of 280 ° C. or higher, particularly an organic solvent that is an alkyl polyol, is 5 with respect to the total mass (100% by mass) of the ink composition. % By mass or less, preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, still more preferably 0.2% by mass or less, Still more preferably, it is 0.1 mass% or less. The lower limit of the content is 0% by mass. As a result, it is possible to obtain excellent abrasion resistance and image quality (bleed suppression) due to the fact that the drying property of the ink composition landed on the recording medium can be obtained at a higher level. Moreover, it is also more preferable from the above-mentioned point that content of the organic solvent whose standard boiling point is more than 250 degreeC is content of the organic solvent whose above-mentioned standard boiling point is 280 degreeC or more.

  Although it does not specifically limit as a kind of organic solvent, For example, a cyclic nitrogen compound, an aprotic polar solvent, a monoalcohol, an alkyl polyol, and glycol ether are mentioned. As the organic solvent of the present embodiment, various organic solvents having a normal boiling point of 150 ° C. or more and 250 ° C. or less can be appropriately selected from these organic solvents. Further, from the viewpoint of abrasion resistance and glossiness, the ink composition preferably does not contain an organic solvent having a standard boiling point of 280 ° C. or higher (an organic solvent including the alkyl polyol), and the content thereof is the ink. If it is 0.5 mass% or less with respect to the total amount of a composition, it is more preferable, and if it is 0.2 mass% or less, it is still more preferable. Further, it is preferable not to contain an organic solvent having a normal boiling point of more than 250 ° C., but the content is more preferably 0.5% by mass or less, and more preferably 0.2% by mass or less with respect to the total amount of the ink composition. Is more preferable.

  The organic solvent preferably contains at least one of a cyclic nitrogen compound and an aprotic polar solvent. The ink composition contains a cyclic nitrogen compound or an aprotic polar solvent, so that the apparent glass transition temperature of the polymer particles can be shifted to a lower temperature side, and the core polymer and shell polymer are softened at a lower temperature than the original. Therefore, the fixability of the ink composition to the recording medium tends to be improved. Thereby, particularly when the recording medium is made of polyvinyl chloride, the fixability of the ink composition to the recording medium can be improved.

  The aprotic polar solvent is not particularly limited, and examples thereof include a cyclic ketone compound, a chain ketone compound, and a chain nitrogen compound. Typical examples of the cyclic nitrogen compound and the aprotic polar solvent include pyrrolidone, imidazolidinone, sulfoxide, lactone, and amide ether solvents. Specifically, among these, 2-pyrrolidone, N-alkyl-2-pyrrolidone, 1-alkyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, imidazole, 1 -Methylimidazole, 2-methylimidazole, and 1,2-dimethylimidazole are preferred.

  Although it does not specifically limit as monoalcohol, For example, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pen Examples include butanol, 3-pentanol, and tert-pentanol.

  Although it does not specifically limit as an alkyl polyol, For example, glycerol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol (1,2-propanediol), dipropylene glycol, 1,3-propylene glycol (1,3-propane) Diol), isobutylene glycol (2-methyl-1,2-propanediol), 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 1 , 2-pentanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1 , 7-Heptanediol and 1,8-octanediol And the like.

  Although it does not specifically limit as glycol ether, For example, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t -Butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monobutyl ether, diethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether , Propylene glycol mono-iso-propyl ether, propylene glycol Call mono -n- butyl ether, dipropylene glycol mono -n- butyl ether, dipropylene glycol mono -n- propyl ether, and dipropylene glycol monomethyl -iso- propyl ether and the like.

  The content of the organic solvent is preferably 5.0% by mass to 50% by mass and more preferably 10% by mass to 30% by mass with respect to the total amount (100% by mass) of the ink composition. When the content of the organic solvent is 50% by mass or less, the drying property of the ink composition attached to the recording medium tends to be further improved. Moreover, when the content of the organic solvent is 5.0% by mass or more, the ejection stability of the ink composition tends to be ensured.

<Polymer particles>
The polymer particles of the present embodiment have a core-shell structure including a core polymer and a shell polymer, and the acid value of the shell polymer is higher than the acid value of the core polymer. “Core-shell structure” refers to a structure in which a core polymer is formed inside voids of a shell polymer. Accordingly, not only a structure in which the surface of the core polymer is covered with the shell polymer but also a structure in which the core polymer is filled in part of the voids of the three-dimensional network structure formed by the shell polymer is included. Therefore, the “core-shell structure” in the present specification includes polymer particles in which the boundary between the core part and the shell part is not strictly clear.

  The glass transition temperature of the core polymer is preferably 0 ° C. or higher and 70 ° C. or lower, more preferably 0 ° C. or higher and 60 ° C. or lower, still more preferably 0 ° C. or higher and 50 ° C. or lower, and even more preferably 0 ° C. or higher. It is 40 degrees C or less. When the glass transition temperature of the core polymer is 70 ° C. or lower, the core polymer can easily flow out after the shell polymer is softened, and therefore, it tends to be more excellent in abrasion resistance. Moreover, when the glass transition temperature of the core polymer is 0 ° C. or higher, the storage stability of the ink composition tends to be superior.

ここで Ｗｎ ；各単量体の質量分率
Ｔｇｎ；各単量体のホモポリマーのＴｇ（単位：Ｋ）
Ｔｇ ；共重合体のＴｇ（単位：Ｋ） The glass transition point (hereinafter also referred to as “Tg”) is measured by differential scanning calorimetry (DSC). Specifically, it is based on the method described in Examples described later. Further, it can be calculated from the Tg of a known homopolymer of a polymerizable monomer using a calculation formula, and can be used as an index for controlling the glass transition point. When the resin contained in the core polymer and the shell polymer described later is a copolymer, the glass transition temperature (Tg) of the copolymer is the Tgn (unit: K) of various homopolymers and the mass fraction of the monomer. It can be calculated from the rate (Wn) by the following FOX equation.

Where Wn: mass fraction of each monomer
Tgn: Tg of homopolymer of each monomer (unit: K)
Tg: Tg of copolymer (unit: K)

  In other words, the glass transition point of the core polymer or shell polymer can be controlled by selecting the homopolymer when the polymer is a homopolymer. Moreover, when a polymer is a copolymer, it can control by considering Tg of the said homopolymer, and the said FOX formula.

  More preferably, the core polymer does not have an acid value. Moreover, it is preferable that a core polymer contains an aromatic monomer unit at least as a structural unit. As a result, the core polymer becomes more hydrophobic than a polymer that does not contain an aromatic monomer unit, so that a more hydrophobic film can be formed on the recording medium. As a result, the rub resistance of the recorded matter tends to be further improved. Here, “structural unit” is a unit constituting a polymer, and “monomer unit” refers to a structural unit derived from the monomer. When the core polymer has an acid value, the acid value of the core polymer is not particularly limited, but from the above viewpoint, it is preferably 0 mgKOH / g or more and 15 mgKOH / g or less, more preferably 0 mgKOH / g or more and 10 mgKOH / g. Or less, more preferably 0 mgKOH / g or more and 5.0 mgKOH / g or less, still more preferably 0 mgKOH / g or more and 5.0 mgKOH / g or less, still more preferably 0 mgKOH / g or more and 2.0 mgKOH / g. It is as follows.

  When the core polymer contains an aromatic monomer unit, the content of the aromatic monomer unit in the core polymer is more preferably 20% by mass with respect to the total amount (100% by mass) of the structural units contained in the core polymer. It is 80 mass% or less, More preferably, it is 30 mass% or more and 75 mass% or less, More preferably, it is 40 mass% or more and 70 mass% or less. As a result, an ink composition excellent in improving the abrasion resistance by the aromatic monomer tends to be obtained.

  Although it does not specifically limit as an aromatic monomer, For example, styrene, (alpha) -methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, and divinylbenzene are mentioned.

  Further, the core polymer is not particularly limited, but as a structural unit, for example, a hydrophilic (meth) acrylate monomer unit, a hydrophobic (meth) acrylate monomer unit having an alkyl group having 3 or more carbon atoms, or a hydrophobic having a cyclic structure It is preferable to contain at least one of a functional (meth) acrylate monomer unit, a (meth) acrylamide monomer unit or an N-substituted derivative unit thereof, and a carboxylic acid monomer unit.

  The hydrophilic (meth) acrylate monomer is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, α-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (poly) Examples include ethylene glycol (meth) acrylate, methoxy (poly) ethylene glycol (meth) acrylate, ethoxy (poly) ethylene glycol (meth) acrylate, and (poly) propylene glycol (meth) acrylate. Among these, methyl (meth) acrylate and ethyl (meth) acrylate are preferable. Here, “hydrophilic” means that the solubility in 100 mL of water (20 ° C.) is 0.3 g or more. When the core polymer contains a hydrophilic (meth) acrylate monomer as a monomer unit, the polymerization reactivity tends to be excellent when the core polymer is produced.

  Although it does not specifically limit as a hydrophobic (meth) acrylate monomer which has a C3 or more alkyl group, For example, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (Meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) ) Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cetyl (meth) acrylate, neopentyl (meth) acrylate, and (meth) acrylate having an alkyl group having 3 or more carbon atoms such as behenyl (meth) acrylate. Relate and the like. Among these, lauryl (meth) acrylate is preferable. Here, “hydrophobic” means that the solubility in 100 mL of water (20 ° C.) is less than 0.3 g.

  The hydrophobic (meth) acrylate monomer having a cyclic structure is not particularly limited, and examples thereof include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl ( Examples include meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate.

  Although it does not specifically limit as a (meth) acrylamide monomer or its N-substituted derivative, For example, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, diacetone acrylamide, and N, N-dimethylacryl (meth) amide (Meth) acrylamide or an N-substituted derivative thereof.

  As described above, it is preferable not to use a carboxylic acid monomer in the core polymer, but it is also possible to use a carboxylic acid monomer to such an extent that the rub resistance of the recorded matter can be maintained at a predetermined level or more. Although it does not specifically limit as a carboxylic acid monomer, For example, (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid are mentioned. Among these, (meth) acrylic acid is preferable. Here, the “carboxylic acid monomer unit” refers to a polymerizable monomer unit having a carboxyl group and a polymerizable unsaturated group.

  The said monomer may be used individually by 1 type, or may use 2 or more types together.

  When the core polymer contains a hydrophobic monomer unit, the content of the hydrophobic monomer unit is preferably 60% by mass or more among all the structural units of the core polymer. When the content of the hydrophobic monomer unit is in the above range, a hydrophobic film is formed on the surface of the image recorded on the recording medium by performing a heat treatment or the like, so that the abrasion resistance is further improved. There is a tendency.

  The glass transition temperature of the shell polymer is preferably 40 ° C. or higher and 150 ° C. or lower, more preferably 50 ° C. or higher and 120 ° C. or lower, still more preferably 60 ° C. or higher and 100 ° C. or lower, and even more preferably 70 ° C. or higher. It is 100 degrees C or less. When the glass composition temperature of the shell polymer is 40 ° C. or higher, when discharging the ink composition in a high temperature environment, the polymer particles are discharged from the recording head without destroying the core-shell structure. Is possible. As a result, since the adhesion of polymer particles in the nozzle can be further suppressed, clogging of the nozzle tends to be further suppressed. In addition, when the glass transition temperature of the shell polymer is 150 ° C. or lower, the shell polymer tends to soften on the recording medium, and therefore, it tends to be more excellent in abrasion resistance. After landing the ink composition on the recording medium, the core polymer flows out of the softened shell polymer by heating the ink composition on the recording medium to a temperature higher than the glass transition temperature of the shell polymer. A film made of a polymer and a shell polymer is formed on the recording medium. At this time, the softened core polymer spreads and adheres onto the recording medium, whereby a film having better abrasion resistance after drying tends to be formed.

  From the viewpoint of making the ink composition of the present embodiment more excellent in ejection stability, the glass transition temperature of the shell polymer is preferably equal to or higher than the glass transition temperature of the core polymer, and the abrasion resistance is more excellent. From this viewpoint, it is preferable that the heating temperature in the heating step of the recording method described later is equal to or higher than the glass transition temperature of the shell polymer. Further, from the same viewpoint, after satisfying the above, the difference between the glass transition temperature of the shell polymer and the glass transition temperature of the core polymer is more preferably 10 ° C. or more, and further preferably 20 ° C. or more. More preferably, it is 30 ° C. or higher.

  The shell polymer is preferably hydrophilic, and more preferably has an acid value. Thereby, even when the drying of water progresses in the recording head and on the recording medium and the occupation ratio of the organic solvent increases, the dispersion of the polymer particles is stable, and the aggregation of the polymer particles tends to be further suppressed. . The acid value of the shell polymer is preferably 20 mgKOH / g or more and 120 mgKOH / g or less. By having an acid value in this numerical range, it is possible to ensure sufficient hydrophilicity as a shell polymer.

  The acid value of the shell polymer is higher than the acid value of the core polymer. Thereby, it is excellent in abrasion resistance and recorded image quality (bleed suppression). Moreover, since the hydrophilicity of the shell polymer is higher than that of the core polymer, it is excellent in suppressing clogging due to the suppression of aggregation between the polymers. From the same viewpoint, it is preferable that the acid value of the shell polymer is 20 mgKOH / g or more, the acid value of the core polymer is 15 mgKOH / g or less, or both. The acid value of the core polymer and the acid value of the shell polymer are determined by calculating from the type and amount of monomers used for each. Specifically, it calculates | requires similarly to the method as described in the Example mentioned later.

  From the same viewpoint as described above, the difference between the acid value of the shell polymer and the acid value of the core polymer is more preferably 5.0 mgKOH / g or more, still more preferably 10 mgKOH / g or more, and still more preferably 20 mgKOH / g or more.

  From the same viewpoint as described above, the acid value of the shell polymer is preferably 20 mgKOH / g or more and 300 mgKOH / g or less, more preferably 25 mgKOH / g or more and 200 mgKOH / g or less, and further preferably 30 mgKOH / g or more and 100 mgKOH / g. g or less, more preferably 30 mgKOH / g or more and 70 mgKOH / g or less, particularly preferably 30 mgKOH / g or more and 50 mgKOH / g or less, and very preferably 30 mgKOH / g or more and 40 mgKOH / g or less.

  The shell polymer preferably contains an aromatic monomer unit as a constituent unit. When the shell polymer contains an aromatic monomer as a structural unit, the detailed action mechanism is unknown, but the discharge bending tends to be suppressed. In particular, since ink droplets are likely to bend when they are small dots, according to one aspect of the present embodiment, this discharge bend is suppressed. Therefore, one aspect of the ink composition of the present embodiment is particularly suitable for a recording head that can eject ink dots in multiple sizes from one nozzle. In addition, when the shell polymer contains a relatively hard aromatic monomer unit, the abrasion resistance of the film formed on the recording medium tends to be further improved.

  When the shell polymer contains an aromatic monomer unit, the content of the aromatic monomer unit in the shell polymer is more preferably 10% by mass with respect to the total amount (100% by mass) of the structural units contained in the shell polymer. More preferably, it is 10 mass% or more and 95 mass% or less, More preferably, it is 20 mass% or more and 90 mass% or less, Most preferably, it is 30 mass% or more and 80 mass% or less, Most preferably It is 40 mass% or more and 70 mass% or less. As a result, an ink composition excellent in improving the abrasion resistance by the aromatic monomer tends to be obtained.

  Moreover, it is preferable that a shell polymer contains a (meth) acrylate monomer unit and a carboxylic acid monomer unit as a structural unit. By using such a polymer, a carboxyl group can be present on the surface of the shell polymer. As a result, the dispersion stability of the polymer particles is further improved, and the viscosity of the ink composition is relatively low, so that the ejection stability tends to be further improved. The (meth) acrylate monomer is not particularly limited. For example, a hydrophilic (meth) acrylate monomer, a hydrophobic (meth) acrylate monomer having an alkyl group having 3 or more carbon atoms, and a hydrophobic ( And (meth) acrylate monomers. Specific examples of the (meth) acrylate monomer and the carboxylic acid monomer include the same ones as described above for the monomer constituting the resin contained in the core polymer, and the monomers may be used alone or in combination of two or more. You may use together.

  When the shell polymer contains a (meth) acrylate monomer unit and an unsaturated carboxylic acid monomer unit, the total content of the (meth) acrylate monomer unit and the unsaturated carboxylic acid monomer unit among all the structural units of the shell polymer is: 20 mass% or more is preferable, 30 mass% or more is more preferable, and 35 mass% or more is further more preferable. As a result, the dispersion stability of the polymer particles is further improved, and the viscosity of the ink composition is further lowered, so that the ejection stability tends to be further improved.

  When the shell polymer contains a hydrophilic monomer unit, the content of the hydrophilic monomer unit is preferably 20% by mass or more and 90% by mass or less, and preferably 30% by mass or more and 80% by mass or less among all the structural units of the shell polymer. More preferably, it is 35 mass% or more and 70 mass% or less. When the content of the hydrophilic monomer unit is not less than the above lower limit value, the shell polymer has hydration properties, so that the dispersion stability of the polymer particles in the ink composition tends to be further improved. Moreover, since it can suppress more effectively that a polymer particle adheres to a nozzle, it exists in the tendency for the discharge stability from the nozzle of a recording head to become more favorable. On the other hand, when the content of the hydrophilic monomer unit is not more than the above upper limit value, the dispersion of polymer particles can be achieved even when the drying rate of water in the recording head and on the recording medium increases and the occupation ratio of the organic solvent increases. Is stable, and the aggregation of polymer particles tends to be further suppressed.

  When the shell polymer contains a hydrophobic monomer unit, the content of the hydrophobic monomer unit is preferably 10% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 70% by mass or less among all the structural units of the shell polymer. More preferably, 30 mass% or more and 65 mass% or less are more preferable. Dispersion of polymer particles is stable even when the content of hydrophobic monomer units is above the above lower limit and the drying rate of water in the recording head and on the recording medium increases and the occupation ratio of the organic solvent increases. And it exists in the tendency which can suppress aggregation of polymer particles more. On the other hand, when the content of the hydrophobic monomer unit is not more than the above upper limit value, the shell polymer has hydration properties, and thus the dispersion stability of the polymer particles in the ink composition tends to be further improved. Moreover, since it can suppress more effectively that a polymer particle adheres to a nozzle, it exists in the tendency for the discharge stability from the nozzle of a recording head to become more favorable.

  Preferably, the polymer particle includes the core polymer and the shell polymer, and includes 10% by mass to 80% by mass (based on the mass of the entire polymer particle) of an aromatic monomer as a structural unit. By containing 10% by mass or more of a relatively hard aromatic monomer, the rub resistance of the recorded matter formed on the recording medium tends to be further improved. Moreover, it is in the tendency which can improve discharge stability more by containing an aromatic monomer 80 mass% or less.

  The average particle diameter of the polymer particles is preferably 20 nm or more and 400 nm or less, more preferably 25 nm or more and 200 nm or less, and further preferably 30 nm or more and 50 nm or less. Thus, when the average particle diameter of the polymer particles is 400 nm or less, excellent glossiness of the recorded material is easily obtained, and the film forming property of the ink composition on the recording medium tends to be excellent. Further, when the average particle diameter of the polymer particles is 400 nm or less, it is difficult to form a large lump even when agglomerated, so that nozzle clogging tends to be further suppressed. Further, when the average particle diameter of the polymer particles is 400 nm or less, the viscosity of the ink composition can be relatively increased, and the ink discharge performance is not improved even when the temperature of the ink composition is increased in the recording head. It tends to be able to suppress the viscosity from decreasing as it becomes more stable. On the other hand, when the average particle diameter of the polymer particles is 20 nm or more, the polymer particles tend to be more easily prepared.

  The average particle diameter in this specification is based on volume unless otherwise specified. As a measuring method, for example, it can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method as a measurement principle. Examples of the particle size distribution measuring device include a particle size distribution meter (for example, Microtrac UPA manufactured by Nikkiso Co., Ltd.) having a dynamic light scattering method as a measurement principle.

  The relationship between the mass of the core polymer and the mass of the shell polymer in the polymer particles is preferably (core-shell polymer mass) ≦ (mass of shell polymer), and more preferably (mass of core-shell polymer) <(shell (Mass of polymer). More preferably, in the polymer particles, when the mass of the shell polymer is 100% by mass, the mass of the core polymer is preferably 40% by mass or more and 80% by mass or less. Thereby, since the balance between the mass of the core polymer and the mass of the shell polymer becomes better, the fixability of the ink composition becomes better, the ejection stability is further improved, and the vertical alignment defect tends not to occur. Here, “longitudinal alignment failure” is a phenomenon in which, in continuous ink ejection, ink is partially solidified around the nozzles by ejecting for a long time, the ejection direction is bent, and clean vertical lines cannot be printed.

  The content of polymer particles in the ink composition (in terms of solid content) is preferably 1.0% by mass or more, more preferably 1.0% by mass or more, based on the total amount (100% by mass) of the ink composition. It is 20 mass% or less, More preferably, it is 1.5 mass% or more and 10 mass% or less, More preferably, it is 2.0 mass% or more and 5.0 mass% or less. When the content of the polymer particles is 1.0% by mass or more, it tends to be more excellent in abrasion resistance and adhesion. Moreover, it exists in the tendency which is more excellent in discharge stability because content of a polymer particle is 20 mass% or less.

<Method for producing polymer particles>
The production method of the polymer particles of the present embodiment is not particularly limited, and examples thereof include an emulsion polymerization method using an emulsifier and a method of forming by soap-free polymerization substantially using no emulsifier, and a method of forming by soap-free polymerization. preferable. Soap-free polymerization refers to a polymerization method in which a core-shell polymer is produced without substantially using an emulsifier. As used herein, “emulsifier” means a surfactant used in synthesis. Moreover, as soap-free polymerization, for example, polymer particles are polymerized in the presence of an emulsifier content in the solution of 1% by mass or less. In soap-free polymerization, for example, a shell polymer containing a (meth) acrylic acid monomer unit is formed, and a core is formed in the shell polymer. In addition, when polymer particles are produced using soap-free polymerization, the average particle diameter becomes very small, and the ejection stability and glossiness of the ink composition tend to be further improved.

  Although it does not specifically limit as surfactant used for a synthesis | combination, Anionic surfactant and a nonionic surfactant are suitable. Although it does not specifically limit as an anionic surfactant, For example, the ammonium salt of sodium dodecyl benzan sulfonate, sodium laurate, and polyoxyethylene alkyl ether sulfate is mentioned. The nonionic surfactant is not particularly limited, and examples thereof include polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, and polyoxyethylene An ethylene alkylamide is mentioned.

  Although it does not specifically limit as a polymerization initiator used by superposition | polymerization, A hydrophilic initiator is used, For example, potassium persulfate, ammonium persulfate, and hydrogen peroxide water are mentioned.

  Although an example of the method of soap free polymerization is demonstrated below, the polymerization method is not restrict | limited to the following. For example, ion-exchanged water and a polymerization initiator are put in a jacketed polymerization reaction tank, the inside of the polymerization tank is depressurized to remove oxygen, and then returned to atmospheric pressure with nitrogen, and the polymerization reaction tank is filled with a nitrogen atmosphere. . Under the nitrogen atmosphere, first, the temperature inside the polymerization reaction tank is set to a predetermined temperature, and then a pre-emulsion solution containing a monomer that is a constituent element of the shell polymer is dropped at a constant rate to synthesize a shell polymer. . Next, using the voids of the obtained shell polymer as a polymerization field, the core polymer is polymerized to synthesize polymer particles according to this embodiment. Specifically, a monomer mixture containing the above-mentioned hydrophobic monomer is dropped into an aqueous dispersion medium containing a shell polymer, and the core polymer is polymerized to form polymer particles. Thus, when the shell polymer is used as the polymerization site for the core polymer, it is not necessary to use an emulsifier in the monomer mixture.

<Wax>
The ink composition of this embodiment preferably further contains a wax. When the recording head is heated, the polymer particles are aggregated and fixed as the water evaporates, causing nozzle clogging of the recording head and possibly preventing stable ejection. On the other hand, the inclusion of wax tends to suppress aggregation of polymer particles during water evaporation. Thereby, ejection failure and clogging due to the adhesion of the polymer particles to the nozzle of the recording head can be suppressed, and as a result, the ink composition is excellent in recording stability. Also, during high temperature recording, the wax tends to suppress the coating with polymer particles from becoming too brittle. For this reason, the ink composition is less likely to deteriorate in abrasion resistance even when recorded at a high temperature.

  The melting point of the wax is preferably 70 ° C. or higher and lower than 110 ° C., more preferably 80 ° C. or higher and 110 ° C. or lower. When the melting point is in the above range, there is a tendency to obtain a recorded material that is more excellent in recording stability and is less susceptible to deterioration in abrasion resistance even during high temperature recording. The melting point can be measured with a differential scanning calorimeter (DSC). Further, the melting point of the wax can be controlled by adjusting the ratio of a plurality of structural units constituting the wax, for example.

  The average particle size of the wax particles is preferably 0.02 μm or more and 0.5 μm or less, and more preferably 0.04 μm or more and 0.3 μm or less. When the average particle diameter is in the above range, the recording stability is excellent, and the abrasion resistance tends to be more difficult to deteriorate even at high temperature recording. The average particle diameter can be measured by the same method as described for the polymer particles.

  The wax is not particularly limited, and examples thereof include (meth) acrylic wax, polyolefin wax such as polyethylene wax, and paraffin wax. Although it does not specifically limit as polyethylene wax, For example, AQUACER593 polyolefin wax (made by BYK), Nopcoat PEM-17 (made by San Nopco) Polylon L787, Polylon L788 (above, Chukyo Yushi Co., Ltd.), and Chemipearl W4005 (Mitsui Chemicals) For example). The wax may be synthesized by a conventional method. Waxes may be used alone or in combination of two or more.

  The wax content (in terms of solid content) in the ink composition is preferably 0.1% by mass or more and 2.5% by mass or less, more preferably 0%, based on the total amount (100% by mass) of the ink composition. .2% by mass or more and 1.0% by mass or less. When the wax content is within the above range, the recording stability tends to be excellent, and the abrasion resistance tends to be more difficult to deteriorate even during high temperature recording.

<Surfactant>
The ink composition preferably further contains a surfactant from the viewpoint of glossiness. The surfactant is not particularly limited, and examples thereof include acetylene glycol surfactants, fluorine surfactants, and silicone surfactants.

  The acetylene glycol surfactant is not particularly limited, but 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5-decyne- One selected from alkylene oxide adducts of 4,7-diol and alkylene oxide adducts of 2,4-dimethyl-5-decyn-4-ol and 2,4-dimethyl-5-decyn-4-ol The above is preferable. Although it does not specifically limit as a commercial item of an acetylene glycol type surfactant, For example, E series (A product made by Air Products Japan (Inc)) (Surfinol 104, etc.), such as Olfine 104 series and Olfine E1010, 465, 61, DF110D (trade name manufactured by Nissin Chemical Industry CO., Ltd.). One acetylene glycol surfactant may be used alone, or two or more acetylene glycol surfactants may be used in combination.

  Although it does not specifically limit as a fluorine-type surfactant, For example, perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate ester, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl betaine, and A perfluoroalkylamine oxide compound is mentioned. Although it does not specifically limit as a commercial item of a fluorochemical surfactant, For example, S-144, S-145 (above brand name, Asahi Glass Co., Ltd. product); FC-170C, FC-430, Fluorard-FC4430 (above product) Name, manufactured by Sumitomo 3M Limited); FSO, FSO-100, FSN, FSN-100, FS-300 (above trade name, manufactured by Dupont); FT-250, 251 (above trade name, manufactured by Neos Co., Ltd.) Can be mentioned. A fluorine-type surfactant may be used individually by 1 type, and may use 2 or more types together.

  Although it does not specifically limit as a silicone type surfactant, For example, a polysiloxane type compound and a polyether modified organosiloxane are mentioned. Although it does not specifically limit as a commercial item of a silicone type surfactant, Specifically, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK -348, BYK-349 (above trade name, manufactured by Big Chemie), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF- 642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. A silicone type surfactant may be used individually by 1 type and may use 2 or more types together.

  The surfactant content is preferably 0.05% by mass to 2.5% by mass and more preferably 0.05% by mass to 1.5% by mass with respect to the total amount (100% by mass) of the ink composition. It is below mass%. When the content of the surfactant is within the above range, the wettability of the ink composition attached to the recording medium tends to be further improved.

  The ink composition includes, as other components, a dissolution aid, a viscosity modifier, a pH adjuster, an antioxidant, an antiseptic, an antifungal agent, a corrosion inhibitor, and a chelate for capturing metal ions that affect dispersion. Various additives such as an agent (for example, sodium ethylenediaminetetraacetate) can be appropriately contained.

[Aggregating liquid]
The aggregation liquid of this embodiment contains an aggregating agent that can aggregate or thicken the ink composition described above. The ink composition of the present embodiment is used in the recording method described later together with the aggregation liquid, and thereby exhibits the effects of the present invention. The aggregating liquid thickens or insolubilizes the ink composition by aggregating components contained in the ink composition when the aggregating agent in the aggregating liquid interacts with the ink composition. Thereby, landing interference and bleeding of the ink composition to be adhered thereafter can be suppressed, and lines, fine images, and the like can be drawn uniformly.

<Flocculant>
The flocculant is not particularly limited, but is preferably one or more selected from the group consisting of organic acids, polyvalent metal salts, and cationic compounds. Thereby, it is in the tendency for a bethamra and a bleed to be suppressed more. Among the components contained in the ink composition, examples of the component that aggregates with the aggregating agent include the above-described pigment, the core polymer and the shell polymer used for the polymer particles, and the wax.

  The organic acid is not particularly limited, but is preferably a carboxylic acid, and examples thereof include maleic acid, acetic acid, phosphoric acid, oxalic acid, malonic acid, and citric acid. Of these, monovalent or divalent or higher carboxylic acids are preferred. By including such a carboxylic acid, the aggregation effect of the polymer and the wax is further improved, and as a result, the color developability tends to be more excellent. In addition, an organic acid may be used individually by 1 type, and may use 2 or more types together.

  The polyvalent metal salt is not particularly limited, but a polyvalent metal salt of an inorganic acid or a polyvalent metal salt of an organic acid is preferable from the viewpoint of more effectively and reliably achieving the effects of the present invention. Such a polyvalent metal salt is not particularly limited, but examples thereof include alkaline earth metals belonging to Group 2 of the periodic table (eg, magnesium, calcium), and transition metals belonging to Group 3 of the periodic table (eg, lanthanum). And salts of earth metals from group 13 of the periodic table (eg, aluminum) and lanthanides (eg, neodymium). Moreover, as a salt of these polyvalent metals, carboxylate (for example, formic acid, acetic acid, benzoate), sulfate, nitrate, chloride, and thiocyanate are suitable. Among them, as polyvalent metal salts, calcium salts or magnesium salts of carboxylic acids (formic acid, acetic acid, benzoates, etc.), calcium salts or magnesium salts of sulfuric acid, calcium salts or magnesium salts of nitric acid, calcium chloride, magnesium chloride, And one or more selected from the group consisting of calcium salts or magnesium salts of thiocyanate are preferred. In addition, a polyvalent metal salt may be used individually by 1 type, and may use 2 or more types together.

  Although it does not specifically limit as a cationic compound, For example, a cationic polymer and a water-soluble metal compound are mentioned. From the viewpoint of more effectively and reliably achieving the effects of the present invention, examples of the cationic polymer include allylamine resins such as polyethyleneimine, polydiallylamine and polyallylamine, alkylamine polymers, JP-A-59-20696, and 59- 33176, 59-33177, 59-1555088, 60-11389, 60-49990, 60-83882, 60-109894, 62-198493, 63-49478 63-115780, 63-280681, JP-A-1-40371, 6-234268, 7-125411, 10-193976, and the like, A polymer having a quaternary ammonium base is preferably used. From the same viewpoint, the weight average molecular weight of these cationic polymers is preferably 5000 or more, more preferably about 5000 to 100,000. The weight average molecular weight of the cationic polymer is measured by gel permeation chromatography using polystyrene as a standard substance.

  The content of the flocculant is preferably 1.0% by mass or more and 20% by mass or less, more preferably 3.0% by mass or more and 17.5% by mass or less, with respect to the total amount (100% by mass) of the aggregation liquid. More preferably, the content is 0.0 mass% or more and 15 mass% or less. When the content of the flocculant is within the above range, betalam and bleed tend to be further suppressed.

  The aggregating liquid used in this embodiment may contain the same surfactant, organic solvent, and water as those used in the ink composition described above. In addition, the agglomerated liquid captures, as other components, dissolution aids, viscosity modifiers, pH adjusters, antioxidants, preservatives, antifungal agents, corrosion inhibitors, and metal ions that affect dispersion. Various additives such as chelating agents can be appropriately added.

  In particular, the content of the organic solvent having a standard boiling point of 280 ° C. or higher in the aggregate liquid is preferably 5% by mass or less, more preferably 3% by mass with respect to the total mass (100% by mass) of the aggregate liquid. Or less, more preferably 1% by mass or less, further preferably 0.5% by mass or less, more preferably 0.2% by mass or less, and further preferably 0.1% by mass or less. . The lower limit of the content is 0% by mass. As a result, it is possible to obtain a higher level of drying property of the aggregating liquid that has landed on the recording medium, resulting in excellent abrasion resistance and image quality of the recorded matter recorded using the ink composition and the aggregating liquid. (Bleed suppression) tends to be obtained. Furthermore, the content of the organic solvent having a standard boiling point of more than 250 ° C. is more preferably the content of the organic solvent having the standard boiling point of 280 ° C. or more.

  In addition, it is also preferable from the above point that the aggregate liquid contains an organic solvent, and the organic solvent is the same as the organic solvent that may be contained in the ink composition.

〔Recording method〕
In the recording method of the present embodiment, recording is performed using the ink composition of the present embodiment and the above-described aggregate liquid. Specifically, it has an attaching step for attaching the ink composition of the present embodiment and the above-mentioned aggregated liquid to a recording medium. Here, the adhering step preferably includes an aggregating liquid adhering step for adhering the aggregating liquid to the recording medium and an ink composition adhering step for adhering the ink composition to the recording medium. In the adhesion process, the ink composition adhesion process may be provided after the aggregation liquid adhesion process, or the aggregation liquid adhesion process may be provided after the ink composition adhesion process, and the aggregation liquid adhesion process and the ink composition adhesion process are performed simultaneously. It may be provided. By using the recording method of the present embodiment, it is possible to improve the rubbing resistance and image quality (bleed suppression) of the recorded matter while maintaining excellent ejection stability. According to the recording method of the present embodiment, in addition to excellent ejection stability, rubbing resistance, and image quality (bleed suppression), it is possible to obtain a recorded matter excellent in glossiness and image quality (color development). Also excellent in suppressing clogging.

[Aggregating liquid adhesion process]
The aggregation liquid attaching step is a step of attaching the aggregation liquid to the recording medium. The means for attaching the aggregating liquid is not particularly limited, and for example, roller coating, spray coating, or an ink jet method can be used. Among these, it is preferable to make it adhere by an inkjet system. By adhering the aggregating liquid by an ink jet method, there is a tendency that the surface quality change of the media is suppressed and the abrasion resistance is further improved.

The adhesion amount of the aggregate liquid to the recording medium is preferably 0.01 mg / inch ^{2 to} 1.0 mg / inch ² and more preferably 0.01 mg / inch ^{2 to} 0.50 mg / inch in terms of solid content. ² or less, more preferably 0.01 mg / inch ² or more and 0.1 mg / inch ² or less. When the amount of adhesion is within the above range, the resulting printed matter tends to be more suppressed from the sticky lines and the ruled line balls.

  When the ink composition adhesion step is provided after the aggregation liquid adhesion step, the time interval from the end of the aggregation liquid adhesion step to the start of the ink composition adhesion step is preferably 10 seconds or less, more preferably 0.10 seconds. 10 seconds or less, more preferably 0.10 seconds or more and 8.0 seconds or less, particularly preferably 0.10 seconds or more and 5.0 seconds or less, and very preferably 0.10 seconds or more and 3.0 seconds or less. Less than a second. Since the time interval from the end of the aggregation liquid adhesion process to the start of the ink composition adhesion process is 10 seconds or less, the reaction efficiency between the aggregation liquid and the ink composition is further improved, and the image quality of the obtained recorded matter is further improved. It tends to improve. In particular, when the film thickness of the film made of the ink composition is small, it is preferable that the time interval is short.

[Ink composition adhesion process]
The ink composition attaching step is a step of attaching the ink composition to the recording medium, and can be provided simultaneously with or before or after the above-described aggregated liquid attaching step. From the viewpoint of more effectively and surely providing, it is preferable to provide after the aggregation liquid adhesion step. The means for attaching the ink composition is not particularly limited, and for example, roller coating, spray coating, and an ink jet method can be used. Among these, it is preferable to make it adhere by an inkjet system. By attaching the ink composition by an ink jet method, there is a tendency that the surface quality change of the media is suppressed and the abrasion resistance is further improved.

  From the viewpoint of further improving the abrasion resistance, the ink composition attaching step is preferably a step of attaching the ink composition to a heated recording medium. The surface temperature of the recording medium is not limited to a lower limit, but is preferably 20 ° C. (normal temperature) or higher, more preferably 25 ° C. or higher, further preferably 30 ° C. or higher, 32 It is particularly preferable that the temperature is not lower than ° C. Further, the upper limit of the surface temperature is not limited, but is preferably 50 ° C. or less, more preferably 45 ° C. or less, further preferably 40 ° C. or less, and 38 ° C. or less. It is particularly preferred. When the surface temperature of the recording medium is normal temperature or higher, the recording medium is preferably heated.

  The film thickness of the dried film after drying the recording area to which the ink composition and the aggregating liquid are adhered is preferably 0.10 to 3.0 μm, more preferably 0.10 to 2.0 μm, More preferably, it is 0.10 to 1.0 μm. When the film thickness of the dry film is 0.10 μm or more, the resulting printed matter tends to be further suppressed from being sticky and ruled lines. Moreover, when the film thickness of the dry film is 3.0 μm or less, the change in glossiness of the obtained recorded product tends to be further suppressed. Here, the “recording area” refers to an area where an image on the surface of the recording medium is formed.

The adhesion amount of the polymer particles to the recording medium is preferably 0.01 mg / inch ² or more and 0.75 mg / inch ² or less, more preferably 0.02 mg / inch ² or more and 0.6 mg / inch in terms of solid content. ² or less, more preferably not more than 0,05mg / inch ² or more 0.5 mg / inch ^2. When the adhesion amount is 0.01 mg / inch ² or more, the resulting printed matter tends to be more suppressed in the printed matter. Further, when the adhesion amount of the polymer particles to the recording area is 0.75 mg / inch ² or less, the glossiness of the obtained recorded matter tends to be more excellent.

[Heating process]
The recording method of the present embodiment further includes a step (heating step) of heating the recording medium on which the ink composition and the aggregation liquid are adhered from the viewpoint of further improving the abrasion resistance. It is preferable. The predetermined heating temperature is not limited to a lower limit, but it is preferably 40 ° C. or higher, more preferably 45 ° or higher, and 50 ° C. or higher from the viewpoint of further improving the abrasion resistance. More preferably, it is still more preferably 60 ° C. or higher, and further preferably 80 ° C. or higher. In addition, from the viewpoint of further improving the abrasion resistance, the predetermined heating temperature is preferably equal to or higher than the glass transition temperature of the shell polymer described above. Moreover, although this heating temperature does not limit an upper limit, it is preferable that it is 200 degrees C or less, It is more preferable that it is 150 degrees C or less, It is further more preferable that it is 100 degrees C or less. The heating step can be realized, for example, by directly heating the recording medium after being discharged from the second drying unit 50 or the recording apparatus provided in the recording apparatus described later.

[Recording medium]
Examples of the recording medium include an absorptive, low-absorbing, and non-absorbing recording medium. Among these, the recording medium is preferably a low absorption recording medium or a non-absorbing recording medium. When a low-absorbing recording medium or a non-absorbing recording medium is used, since the aggregating liquid is repelled on the surface and the aggregating agent is difficult to be applied uniformly, betalam and bleeding are more likely to occur. However, the present embodiment is particularly useful because the aggregation liquid can be prevented from being repelled by the ink composition. In addition, when a low-absorbing recording medium or a non-absorbing recording medium is used, the flocculant does not penetrate into the recording medium and tends to remain on the surface of the recording medium. Tend to. However, in the present embodiment, since the amount of the aggregation liquid used can be reduced by using the above-described ink composition, the stickiness of the recording surface can be improved, which is particularly advantageous.

Here, the “low-absorbing recording medium” or “non-absorbing recording medium” refers to a recording medium having a water absorption of 10 mL / m ² or less from the start of contact to 30 msec in the Bristow method. . This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (JAPAN TAPPI). For details of the test method, refer to Standard No. of “JAPAN TAPPI Paper Pulp Test Method 2000”. 51 "Paper and paperboard-Liquid absorbency test method-Bristow method".

  Further, the non-absorbent recording medium or the low-absorbing recording medium can be classified by the wettability of the recording surface with respect to water. Specifically, a 0.5 μL water droplet is dropped on the recording surface of the recording medium, and the contact angle reduction rate (comparison of the contact angle at 0.5 milliseconds after the landing and the contact angle at 5 seconds) is measured. Can be used to characterize the recording medium. More specifically, as a property of the recording medium, the non-absorbing property of the “non-absorbing recording medium” indicates that the above-described reduction rate is less than 1%, and the low absorption of the “low-absorbing recording medium”. The property indicates that the decrease rate is 1% or more and less than 5%. Moreover, absorptivity means that said reduction rate is 5% or more. In addition, a contact angle can be measured using portable contact angle meter PCA-1 (made by Kyowa Interface Science Co., Ltd.) etc.

  The absorbent recording medium is not particularly limited. For example, plain paper such as electrophotographic paper having a high penetrability of the ink composition, inkjet paper (an ink absorbing layer composed of silica particles or alumina particles, or polyvinyl chloride). Art paper used for general offset printing in which the ink composition has a relatively low permeability from an alcohol (PVA) or polyvinyl pyrrolidone (PVP) or other hydrophilic polymer such as an ink-absorbing layer. , Coated paper and cast paper.

  Although it does not specifically limit as a low absorptive recording medium, For example, the coated paper by which the coating layer for accepting oil-based ink was provided in the surface is mentioned. The coated paper is not particularly limited, and examples thereof include printing paper such as art paper, coated paper, and matte paper.

  The non-absorbable recording medium is not particularly limited. For example, a plastic film that does not have an ink absorbing layer, a substrate such as paper coated with plastic, or a plastic film bonded thereto Etc. Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

  In addition to the above recording medium, a non-ink-absorbing or low-absorbing recording medium such as a plate of metals such as iron, silver, copper, and aluminum, or glass can also be used.

  In particular, the recording medium is preferably in the form of a roll. The roll-shaped recording medium can be used in such a manner that when recording, the recording head is scanned once relative to the recording medium and wound by a winding roller. When such a recording medium is used, when all the colors cannot be recorded by one feeding due to a large number of types of colored ink to be used, and the recording medium is recorded many times, the recording medium is recorded multiple times. On the other hand, a recorded matter can be obtained by repeating the operation of scanning the recording head relatively once and winding it with a winding roller. However, because of the roll shape, cracks tend to occur in the layer formed of the polymer in the recorded matter. When a crack occurs, the image quality of the obtained recorded matter tends to deteriorate due to the reason that the aggregate liquid penetrates into the crack. However, the coating film made of the ink composition obtained by the recording method of the present embodiment is less susceptible to cracking. Therefore, the present invention is particularly useful when a recording medium having such a shape is used.

[Recording device]
Next, a recording apparatus that can be used in the recording method of the present embodiment will be described. 1 is a side view showing an outline of an example of an inkjet recording apparatus 1 that can be used in the present embodiment. As shown in FIG. 1, the inkjet recording apparatus 1 includes a recording medium feeding unit 10, a transport unit 20, a recording unit 30, a drying device 90, and a discharge unit 70.

  Among these, the drying device 90 includes a first drying unit 40 that dries the aggregation liquid, and a second drying unit 50 that dries the recorded matter obtained by the recording method according to the present embodiment.

  Further, the feeding unit 10 is provided so that the roll-shaped recording medium F can be fed to the transport unit 20. Specifically, the feeding unit 10 includes a roll medium holder 11, and the roll medium holder 11 holds a roll-shaped recording medium F. Then, by rotating the roll-shaped recording medium F, the recording medium F can be fed to the conveyance unit 20 on the downstream side in the feeding direction Y.

  Further, the transport unit 20 is provided so that the recording medium F sent from the feeding unit 10 can be transported to the recording unit 30. Specifically, the transport unit 20 includes a first feed roller 21 and is configured to be able to transport the sent recording medium F further to the recording unit 30 on the downstream side in the feed direction Y.

  The recording unit 30 is provided so that the recording medium F sent from the transport unit 20 is coated with an aggregating liquid, and an ink composition can be discharged and recorded. Specifically, the recording unit 30 includes heads 31 and 32 that perform an aggregation liquid attaching step, a recording head 33 that performs an ink composition attaching step, and a platen 34 as a medium support portion.

  Among these, the platen 34 is provided so that the recording medium F can be supported from the back surface. The platen 34 is provided with a first drying unit 40 that dries the agglomerated liquid adhering to the recording medium F and the ink composition adhering to the recording medium F. Further, a second feed roller 43 is provided downstream of the platen 34 in the feed direction Y. The second feed roller 43 is configured to send the recorded recording medium F to the second drying unit 50 on the downstream side in the feed direction Y.

  The second drying unit 50 is configured to further dry the aggregating liquid adhering to the recording medium F and the ink composition adhering to the recording medium F. Further, a third feed roller 65 is provided in the vicinity of the outlet 64 of the second drying unit 50. The third feed roller 65 is disposed so as to be in contact with the back surface of the recording medium F, and is configured to be able to feed the recording medium F to the discharge unit 70 on the downstream side in the feeding direction Y.

  Further, the discharge unit 70 is provided so that the recording medium F sent from the second drying unit 50 can be further sent downstream in the feed direction Y and discharged to the outside of the inkjet recording apparatus 1. Specifically, the discharge unit 70 includes a fourth feed roller 71, a fifth feed roller 72, a sixth feed roller 73, a seventh feed roller 74, and a take-up roller 75. Among these, the 4th feed roller 71 and the 5th feed roller 72 are arrange | positioned so that the surface of the recording medium F may be contacted. Moreover, the 6th feed roller 73 and the 7th feed roller 74 are arrange | positioned so that a roller pair may be comprised. The recording medium F discharged by the sixth feed roller 73 and the seventh feed roller 74 is provided so as to be taken up by the take-up roller 75.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited in any way by the following examples. In the following, “polymer particles having a core-shell structure” are referred to as “core-shell polymer particles”.

[Material for aqueous dispersion of core-shell polymer particles]
Styrene (Tg: 80 ° C)
n-Butyl acrylate (Tg: -55 ° C)
Methyl acrylate (Tg: 10 ° C)
Methyl methacrylate (Tg: 105 ° C)
Acrylic acid (Tg: 106 ° C)

[Preparation of aqueous dispersion of core-shell polymer particles]
A reaction vessel equipped with a dropping device, a thermometer, a water-cooled reflux condenser, and a stirrer was prepared in the reaction vessel. 100 parts by mass of ion-exchanged water was put into the reaction vessel, and 0.2 parts by mass of a polymerization initiator ammonium persulfate was added at 70 ° C. in a nitrogen atmosphere while stirring. Next, a monomer solution containing 20 parts by mass of styrene, 17 parts by mass of methyl acrylate, 30 parts by mass of methyl methacrylate, and 5.0 parts by mass of acrylic acid was prepared. The monomer solution was dropped into the reaction vessel and reacted to polymerize and prepare a shell polymer. Thereafter, a mixed liquid of 0.2 parts by mass of potassium persulfate, 50 parts by mass of styrene, and 22 parts by mass of n-butyl acrylate was dropped into the reaction vessel, and a polymerization reaction was performed while stirring at 70 ° C. Then, the aqueous dispersion (polymer particle A) of the core-shell type polymer particle was prepared by neutralizing with sodium hydroxide, adjusting pH to the range of 8-8.5, and filtering with a 0.3 micrometer filter.

  Further, as shown in Table 1, except that the content ratio (unit: part by mass) of the monomers constituting the shell polymer and the core polymer was changed, the polymer particles B to G was prepared.

[Average particle size]
The polymer particles obtained above were measured by “Microtrack UPA” (Nikkiso Co., Ltd.), and the average particle diameter φ (nm) of the core-shell type polymer particles was determined.

[Acid value]
For the polymer particles, the acid value of the core polymer was determined from the following formula.
Acid value of core polymer (mgKOH / g) = acrylic acid (parts by mass) used for core polymer / total core polymer (parts by mass) /72.06×56.11×1000
Further, the acid value of the shell polymer was determined from the same formula except that the core polymer was replaced with the shell polymer in the above formula.

[Tg]
The polymer particles obtained above are subjected to differential scanning calorimetry (DSC) in accordance with JIS K7121, and the glass transition temperature (Tg, unit: ° C) of the polymer constituting the core polymer and the polymer constituting the shell polymer are respectively determined. Asked. A model “DSC 6220” manufactured by Seiko Denshi Co., Ltd. was used as the differential scanning calorimeter.

  In Table 1, the content ratio of each monomer, average particle diameter, acid value, Tg, and aromatic monomer unit content in the polymer particles A to G are also shown.

[Material for ink composition]
The main materials for the ink composition used in the preparation of the following recorded matter are as follows.
[Polymer particles]
Aqueous dispersions A to G of core-shell polymer particles
[Color material]
Carbon black (organic solvent)
1,3-butanediol (standard boiling point: 223 ° C.)
2-pyrrolidone (standard boiling point: 245 ° C)
[Surfactant]
BYK348 (trade name, manufactured by Big Chemie)
Surfynol DF110D (trade name, manufactured by Air Products)
[PH adjuster]
Sodium triethanolamine ethylenediaminetetraacetate

[Preparation of ink composition]
Each material was mixed with the composition shown in Table 2 below, and stirred sufficiently to obtain an ink composition. In Table 2 below, the numerical unit is mass%, and the total is 100.0 mass%.

[Material for flocculant]
The main materials for the aggregating liquid used in the production of the following recorded matter are as follows.
[Flocculant]
Calcium acetate Magnesium sulfate Epichlorohydrin polymer [solvent]
1,2-hexanediol 2-pyrrolidone glycerin [surfactant]
BYK348 (trade name, manufactured by Big Chemie)

[Preparation of flocculant]
Each material was mixed with the composition shown in Table 3 below and stirred sufficiently to obtain an agglomerated liquid. In Table 3 below, the numerical unit is mass%, and the total is 100.0 mass%.

[Preparation of recorded material]
Prepare an inkjet printer, which is a modified machine of PX-G930 (trade name manufactured by Seiko Epson) with a heater attached to the platen, and record media (clear loop film, A4, manufactured by Seiko Epson) on the platen. The surface temperature was adjusted with a heater so as to be the primary heating temperature shown in Table 4. Next, the recording medium is transferred to the printer, the aggregation liquid is filled in one row of nozzles of the recording head, the ink composition is filled in one row of other nozzles, and the aggregation liquid filled in the recording head is supplied. The ink was applied by an inkjet method with a resolution of 720 × 720 dpi and an adhesion amount of 1.7 mg / inch ² . Next, the recording medium is rewound, and the ink composition filled in the recording head is overlaid on the pattern of the aggregated liquid adhesion surface on which the aggregated liquid is adhered, and the resolution is 720 × 720 dpi, and the adhesion amount is 12 mg / inch ^2. Inkjet coating was performed to obtain a recorded material on a recording medium. Thereafter, the recording medium was discharged from the printer, and the recording medium was left to stand in an environment of 100 ° C. for 2 minutes and dried.

[Abrasion resistance]
A recorded material was obtained by the same method as in [Preparation of recorded material]. The recorded material is allowed to stand at room temperature (25 ° C.) for 1 hour, and then a white cotton cloth (JIS L 0803 compliant) is applied to the Gakushin type friction fastness tester AB-301 (trade name, manufactured by Tester Sangyo Co., Ltd.). The attached friction element was rubbed for 20 reciprocations until the recorded material was peeled off under a load of 200 g. And the peeling of the recorded matter of the recording medium was observed visually, and the abrasion resistance was evaluated according to the following evaluation criteria. Table 4 shows the obtained results.
(Evaluation criteria)
A: No scratches or peeling of recorded material was observed.
B: Scratches or peeling of the recorded matter was observed in less than 1.0% of the rubbed area (stroke area).
C: Scratches or peeling of recorded matter was observed in 1.0% or more and less than 10% of the rubbed area (stroke area).
D: Scratches or peeling of the recorded matter was observed in 10% or more and less than 50% of the rubbed area (stroke area).
E: Scratches or peeling of the recorded matter was observed in 50% or more of the rubbed area (stroke area).

[Glossiness]
Using a gloss measuring device (GM-268Plus, manufactured by Konica Minolta Co., Ltd.), a 60 ° glossiness based on JIS Z8741 is obtained for a recorded product obtained by the same method as [Preparation of Recorded Product]. Measured and evaluated for gloss. Higher gloss value means better gloss. The obtained results (glossiness) are shown in Table 4.

[Image quality (color development)]
About the obtained recorded matter, the optical density (OD value) was measured with an OD measuring device (Spectrolino, trade name of Gretag Macbeth Co., Ltd.), and the image quality (coloring property) was evaluated according to the following evaluation criteria. Table 4 shows the obtained results.
(Evaluation criteria)
A: OD value is 1.5 or more B: OD value is 1.2 or more and less than 1.5 C: OD value is less than 1.2

[Image quality (bleed)]
The recorded matter evaluated in the above [Rubbing resistance] was visually checked for bleed under room temperature (25 ° C.) conditions, and the image quality (betamula) was evaluated according to the following evaluation criteria. Table 4 shows the obtained results.
(Evaluation criteria)
A: No bleed was observed in the solid pattern and in the outline.
B: Some bleed was recognized in the solid pattern and / or in the outline.
C: Bleed was observed in the outline portion of the solid pattern, and the bleed was recognized slightly exceeding the amount inside.

[Clogging]
Prepare an ink jet printer of PX-H8000 (trade name, manufactured by Seiko Epson), fill the ink cartridge with the ink composition, and open the cartridge cap for 1 month at room temperature. I left it alone. Thereafter, the 360 nozzles of the cartridge were subjected to head cleaning three times, and the clogging property was evaluated according to the following evaluation criteria. Table 4 shows the obtained results.
(Evaluation criteria)
A: The number of defective nozzles and the number of nozzles whose ejection direction is shifted are 0 with respect to the total number of nozzles.
B: The number of defective nozzles and the number of nozzles whose ejection directions are shifted are 1 to 5 with respect to the total number of nozzles.
C: The number of nozzles with defective ejection and the number of nozzles with different ejection directions are 6 to 20 with respect to the total number of nozzles.
D: The number of nozzles with defective ejection and the number of nozzles with different ejection directions are 21 or more with respect to the total number of nozzles.

(Discharge stability)
The above [Preparation of Recorded Material] was continuously performed on 100 recording media, and the clogging property of the ink composition was evaluated according to the following evaluation criteria. Table 4 shows the obtained results.
(Evaluation criteria)
AA: The number of defective nozzles and the number of nozzles whose ejection direction is shifted are zero with respect to the total number of nozzles.
A: The number of nozzles with defective ejection and the number of nozzles with different ejection directions are 1 to 5 with respect to the total number of nozzles.
B: The number of nozzles with defective ejection and the number of nozzles with different ejection directions are 6 to 20 with respect to the total number of nozzles.
C: The number of nozzles with defective ejection and the number of nozzles with the ejection direction shifted are 21 or more with respect to the total number of nozzles.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording apparatus, 10 ... Feed part, 11 ... Roll medium holder, 20 ... Conveyance part, 21 ... 1st feed roller, 30 ... Recording part, 31 ... Head, 32 ... Head, 33 ... Recording head, 34 ... Platen, 40 ... 1st drying part, 43 ... 2nd feed roller, 50 ... 2nd drying part, 64 ... Exit, 65 ... 3rd feed roller, 70 ... Discharge part, 71 ... 4th feed roller, 72 ... 1st 5 feed roller, 73 ... 6th feed roller, 74 ... 7th feed roller, 75 ... take-up roller, 90 ... drying device, F ... recording medium, Y ... feed direction.

Claims (11)

An ink composition comprising water and polymer particles,
The polymer particles have a core-shell structure comprising a core polymer and a shell polymer;
The acid value of the shell polymer is higher than the acid value of the core polymer,
The content of the organic solvent having a standard boiling point of 280 ° C. or higher is 5% by mass or less with respect to the total mass of the ink composition,
Used in a recording method for recording using the ink composition and an aggregating liquid containing an aggregating agent capable of aggregating or thickening the components of the ink composition.
Ink composition. The acid value of the shell polymer is at least 20 mgKOH / g, and the acid value of the core polymer is at least 15 mgKOH / g or less.
The ink composition according to claim 1. The recording method includes an ink composition attaching step in which the ink composition is attached to a recording medium having a surface temperature of 40 ° C. or less.
The ink composition according to claim 1 or 2. The recording method further includes a step of heating the recording medium on which the ink composition and the aggregation liquid are adhered to a heating temperature of 45 ° C. or higher.
The ink composition according to any one of claims 1 to 3. The glass transition temperature of the shell polymer is not less than the glass transition temperature of the core polymer,
The heating temperature is equal to or higher than the glass transition temperature of the shell polymer.
The ink composition according to claim 4. The content of the polymer particles is 1.0% by mass or more based on the total amount of the ink composition.
The ink composition according to any one of claims 1 to 5. The shell polymer contains at least an aromatic monomer unit as a structural unit,
The content of the aromatic monomer unit is 10% by mass or more based on the total amount of the structural units contained in the shell polymer.
The ink composition according to any one of claims 1 to 6. The flocculant is one or more selected from the group consisting of polyvalent metal salts, organic acids, and cationic compounds.
The ink composition according to any one of claims 1 to 7. The average particle diameter of the polymer particles is 20 nm or more and 400 nm or less.
The ink composition according to any one of claims 1 to 8. Further comprising an organic solvent,
The organic solvent includes an organic solvent having a normal boiling point of 150 ° C. or higher and 250 ° C. or lower.
The ink composition according to any one of claims 1 to 9. An aggregating liquid adhering step of adhering an aggregating liquid containing an aggregating agent capable of aggregating or thickening the components of the ink composition according to claim 1 to a recording medium;
An ink composition attaching step for attaching the ink composition to a recording medium,
Recording method.

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