JP2017114991A - Ink, ink storage container, ink jet recording method, ink jet recording device, and recorded matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink excellent in dispersion stability, capable of obtaining high image density even in the case of plain paper, and also, capable of forming an image excellent in scratch resistance.SOLUTION: Provided is an ink containing urethane resin particles involving water, an organic solvent and a color material, in which the volume average particle diameter by a dynamic light scattering method of the urethane resin particles involving the color material is 70 to 300 nm, and the fracture energy of an ink film obtained by drying the ink is 20 to 200 mJ.SELECTED DRAWING: None

Description

  The present invention relates to an ink, an ink container, an ink jet recording method, an ink jet recording apparatus, and a recorded matter.

Conventionally, as means for dispersing a pigment as a colorant in water-based ink, for example, a method using a surfactant as a dispersant (see Patent Document 1), a method using a resin having a hydrophobic part and a hydrophilic part as a dispersant (See Patent Document 2) and the like.
In order to improve image quality, attempts have been made to add acetylene glycol, acetylene alcohol, silicone activator, alkylene glycol monoalkyl ether, or a mixture thereof as a dispersion aid in the ink.

  However, when a dispersant or a dispersion aid is used as described above, a residue such as a dispersant remains in the ink, and does not contribute sufficiently to the dispersion, so that the ink is released from the pigment and has a high viscosity. When the viscosity is high, the content of a color material such as a pigment is limited, and there is a problem that sufficient image quality cannot be obtained.

  In order to solve the above problems, a method for coating the surface of a color material has been proposed. For example, a method using a microcapsule containing a dye ink (see Patent Document 3), a method in which a dye insoluble in water is dispersed or dissolved in an organic solvent, and this is coated with a polymer emulsified in water together with a surfactant. (See Patent Document 4), a method of using an inclusion in which a sublimable disperse dye is dissolved or dispersed in at least one of water, a water-soluble solvent, and polyester as a microcapsule (see Patent Document 5), a phase inversion emulsification reaction And a method by acid precipitation (see Patent Document 6).

  An object of the present invention is to provide an ink that is excellent in dispersion stability, can provide a high image density even with plain paper, and can form an image excellent in scratch resistance.

The ink of the present invention as a means for solving the above problems is an ink containing urethane resin particles containing water, an organic solvent, and a coloring material,
The volume average particle diameter of the urethane resin particles encapsulating the coloring material by a dynamic light scattering method is 70 nm or more and 300 nm or less,
The breaking energy of the ink film obtained by drying the ink is 20 mJ or more and 200 mJ or less.

  According to the present invention, it is possible to provide an ink that is excellent in dispersion stability, can provide a high image density even with plain paper, and can form an image excellent in scratch resistance.

FIG. 1 is a scanning transmission electron microscope (STEM) photographic image (an image on the left is a bright-field image and a image on the right is a dark-field image) showing an example of urethane resin particles encapsulating a color material. FIG. 2 is a scanning transmission electron microscope (STEM) photographic image (a left figure is a bright field image and a right figure is a dark field image) showing another example of urethane resin particles encapsulating a color material. FIG. 3 is a perspective explanatory view showing an example of an ink jet recording apparatus. FIG. 4 is a perspective explanatory view showing an example of a main tank in the ink jet recording apparatus.

The ink of the present invention contains urethane resin particles enclosing water, an organic solvent, and a color material,
The volume average particle diameter of the urethane resin particles encapsulating the coloring material by a dynamic light scattering method is 70 nm or more and 300 nm or less,
The breaking energy of the ink film obtained by drying the ink is 20 mJ or more and 200 mJ or less, and further contains other components as necessary.

  In the ink of the present invention, in the conventional method of coating the pigment, the amount of resin added is large compared to the conventional pigment dispersion method ink, and the dispersion of the pigment is difficult, and styrene or acrylic resin is the main constituent. Since it is contained as a component, it does not have sufficient fixability to various recording media, and it is necessary to apply a primer such as an ink-receiving layer, resulting in a decrease in environmental compatibility and productivity. It is based on the knowledge that it is easy to do.

The volume average particle diameter by the dynamic light scattering method of the urethane resin particles encapsulating the coloring material is 70 nm or more and 300 nm or less, and preferably 100 nm or more and 250 nm or less.
In the range where the volume average particle diameter is 70 nm or more and 300 nm or less, the occurrence of ink bleeding is prevented and the ink dispersion stability is improved.
The volume average particle size is determined by using an ELSZ-1000 manufactured by Otsuka Electronics Co., Ltd., after diluting the ink with ion-exchanged water so that the solid content concentration is 0.5% by mass, and measuring the light amount at 25 ° C. Measurement was performed with an optimum value of 30,000 (maximum value of 50,000, minimum value of 10,000), pinhole 50 and dust cut tolerance of 5%, and analysis was performed by the Marquart method, and the color material in the ink was included. The volume average particle diameter of the urethane resin particles can be determined.

The breaking energy of the ink film obtained by drying the ink is 20 mJ or more and 200 mJ or less, and preferably 50 mJ or more and 200 mJ or less.
When the breaking energy is 200 mJ or less, good ink dispersion stability can be maintained, and liquid bending and image warping during ejection do not occur. Further, when the breaking energy is 20 mJ or more, the ink film is not brittle, the surface is not sticky, and the blocking resistance and abrasion resistance are improved.
The breaking energy of the ink film can be measured using, for example, Autograph AG-10N manufactured by Shimadzu Corporation.

The glass transition temperature (Tg) of the ink film is preferably 20 ° C. or lower.
When the glass transition temperature is 20 ° C. or less, it is possible to obtain urethane resin particles having excellent adhesion between particles and a recording medium at the time of drying and interpenetrating input, and the breaking energy and scratch resistance. It can contribute to improvement of sex.
The glass transition temperature (Tg) can be measured using, for example, a differential scanning calorimeter (TA-60WS and DSC-60, manufactured by Shimadzu Corporation).
First, 5.0 mg of an ink film is placed in an aluminum sample container, and the sample container is placed on a holder unit and set in an electric furnace. Next, the temperature was raised from 0 ° C. to 150 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, and then the temperature was lowered from 150 ° C. to −80 ° C. at a temperature lowering rate of 5 ° C./min. The DSC curve is measured by raising the temperature to 150 ° C./min. From the obtained DSC curve, using the analysis program in the DSC-60 system, the inflection part at the second temperature rise can be analyzed by the midpoint method to obtain the glass transition temperature (Tg).

The absolute zeta (ζ) potential of the ink is preferably 40 mV or more, and more preferably 70 mV or more.
When the zeta potential is 40 mV or more in absolute value, the dispersion stability and viscosity of the ink are stable, and there is no aggregation or the like due to long-term storage or environmental changes, and it is possible to prevent thickening or thinning.
The zeta potential is measured by, for example, diluting with ion-exchanged water so that the solid content concentration of the ink is 0.05% by mass, using ELSZ-1000 manufactured by Otsuka Electronics Co., Ltd., measuring temperature 25 ° C., flow cell. The zeta potential in the ink can be obtained by performing measurement using and analyzing based on the Smolchowski equation.

<Urethane resin particles containing color material>
Since the urethane resin allows various interactions between molecules and between molecules, it is possible to obtain fixing properties and high film strength for various recording media without using a primer such as an ink receiving layer. Therefore, the durability of the image is also excellent. Among these, urethane resins exhibiting elastomeric characteristics are more preferable.
It is possible to satisfy storage stability even with water-insoluble polymers such as vinyl resins other than urethane resins, polyester resins, and polyamide resins. However, compatibility with recording media such as paper is low, or film strength is increased. However, the durability of the image is inferior, and there is a problem that further addition or injection of a resin emulsion is necessary. Further, a vinyl resin containing styrene as a main component is not preferable because an ink receiving layer is required.

Here, the “encapsulation” means a state in which the surface of the colorant particles is covered with a urethane resin, as shown in FIGS. 1 and 2. The colorant particles are preferably completely covered with a urethane resin, but may be partially exposed.
The inclusion of the coloring material in the urethane resin particles can be confirmed, for example, by observing the urethane resin particle emulsion containing the coloring material using a scanning transmission electron microscope (STEM). As a result of direct confirmation as described above, even when all the colorant particles are not completely covered and partially exposed, the ink viscosity at 25 ° C. is 20 mPa · s or less at room temperature. If the color material particles and the urethane resin particles do not precipitate even after standing for 1 week or longer, it is determined that the urethane resin particles containing the color material exist.

As the color material in the urethane resin particles encapsulating the color material, either a dye or a pigment is preferable, and a pigment is more preferable in terms of scratch resistance.
Details of the color material will be described later.
The content of the color material in the urethane resin particles encapsulating the color material is preferably 10 parts by mass or more and 50 parts by mass or less, and more preferably 20 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the polyurethane resin.
Within the numerical range of the content of the color material, the color material can be well embedded, and an image with excellent color reproducibility and image density can be formed.

The urethane resin particles encapsulating the coloring material are preferably present in the state of a resin emulsion dispersed with water as a dispersion medium.
As a method of dispersing the urethane resin particles encapsulating the coloring material in an aqueous medium, there are a forced emulsification method using a dispersing agent and a self-emulsification method using a hydrophilic group added to the surface of the urethane resin particles. Can be mentioned.
In the case of the forced emulsification method, it is preferable to use the self-emulsification method because a dispersant remains in the coating film and the coating film strength may be lowered.
As the hydrophilic group, any of an anionic group, a cationic group, and a nonionic group can be suitably used, but an anionic group is preferable from the viewpoint of dispersion stability and prevention of yellowing.
Examples of the anionic group include a carboxyl group, a carboxylate group, a sulfonic acid group, and a sulfonate group. Among these, a carboxylate group and a sulfonate group, which are partially or completely, preferably all neutralized with a basic compound or the like, are particularly preferable.

  Examples of the anionic self-emulsifying urethane resin include polymer polyol, polyisocyanate, nonionic short-chain polyhydric alcohol, and ionic short-chain polyhydric alcohol containing a carboxyl group and an active hydrogen atom-containing group in the molecule. The urethane prepolymer is formed in a single stage or multiple stages by charging an active hydrogen-containing component consisting of the above and an organic solvent as necessary. Next, after hydrophilization (neutralization) or while hydrophilizing, if necessary, it is mixed with an aqueous medium containing a chain extender, a crosslinking agent and / or a terminator to form a urethane resin emulsion, and NCO groups (isocyanate groups) are substantially contained. It can be produced by carrying out water or chain extension and crosslinking reaction and / or reaction termination until it is completely eliminated.

The identification of the urethane resin is not particularly limited and can be easily performed by a conventionally known method. Specifically, elemental analysis, infrared absorption (IR) measurement, (pyrolysis) GC / MS measurements, composition analysis by high-resolution NMR measurements ^(such as ^{1 H, 13 C, 13 C} -CP / MS), potentiometric titration, etc. The determination of the hydrophilicity imparting group by quantifying the amount of acid and amine by means of, the zeta (ζ) potential by the zeta (ζ) potentiometer, ie, the measurement of electrostatic repulsive force, etc. it can.
These characteristics of the ink and ink film can be controlled by the solid content of the ink as will be described later, but are largely dependent on the anionic functional group amount and urea bond amount of the self-emulsifying urethane resin.

The content of the anionic group in the self-emulsifying urethane resin is preferably 1% by mass or more and 2.5% by mass or less.
When the content of the anionic group is 1% by mass or more and 2.5% by mass or less, a film having excellent dispersion stability and excellent blocking resistance and abrasion resistance is obtained by having appropriate hydrophilicity. Is possible.
The content of the anionic group can be calculated, for example, by the following formula.
100 x number of polyhydric alcohol equivalents having an anionic group x anionic group molecular weight / urethane resin solid content

The content of the urea group in the self-emulsifying urethane resin is preferably 0.1% by mass or more and 9.0% by mass or less, and more preferably 0.5% by mass or more and 7.5% by mass or less.
By increasing the content of the urea group, a strong cohesive force based on the hydrogen bond of the urea group can form a strong hard segment, which is excellent in both strength and elongation, that is, a tough film with high breaking energy And an image excellent in blocking resistance and abrasion resistance can be formed. Further, since the solvent resistance is also improved, it contributes to the improvement of the stability as an ink.
The urea group content can be calculated, for example, by the following formula.
100 × [total isocyanate equivalent number−total polyol equivalent number−total polyhydric alcohol equivalent number] × (urea group molecular weight / urethane resin solid content)

-Polymer polyol-
The polymer polyol used in the polyurethane is not particularly limited, and any of the conventionally known polymer polyols can be suitably used. Polycaprolactone-based polyols, carbonate-based polyols, and polyether-based polyols are resistant to hydrolysis. It is preferable in terms of durability, mechanical properties, and cost.
The number average molecular weight (Mn) of the polymer polyol is preferably 400 or more and 5,000 or less, and more preferably 1,000 or more and 3,000 or less, from the viewpoints of breaking energy of the ink film, thermal characteristics, and the like.
When the number average molecular weight (Mn) of the polymer polyol is 400 or more and 5,000 or less, the contribution of the hard segment is lowered, resulting in a decrease in strength, which tends to be sticky. Since urethane groups and urea groups are too close to each other, a hard and brittle film is not preferable. In any case, it is not preferable because it tends to make it difficult to satisfy the breaking energy.
The number average molecular weight (Mn) can be measured, for example, using gel permeation chromatography (hereinafter referred to as GPC) with tetrahydrofuran as a solvent and polystyrene as a standard.

The polycaprolactone polyol is a polyaddition product of ε-caprolactone to a low molecular polyol having a number average molecular weight (Mn) of less than 400.
Examples of the polycaprolactone polyol include polycaprolactone diol and polycaprolactone triol.

  The polycarbonate polyol preferably has 4 to 12 carbon atoms, more preferably 6 to 10 carbon atoms, and one or more alkylene diols having an alkylene group having 6 to 9 carbon atoms, and a low molecular carbonate compound ( For example, from an alkyl group having 1 to 6 carbon atoms, an alkylene carbonate having an alkylene group having 2 to 6 carbon atoms, a diaryl carbonate having an aryl group having 6 to 9 carbon atoms, etc. The polycarbonate polyol etc. which are manufactured by this are mentioned.

Examples of the alkylene diol having an alkylene group having 4 to 12 carbon atoms include linear alkylene diols and branched alkylene diols.
Examples of the linear alkylene diol include 2-methylpentanediol, 3-methylpentanediol, 2-methylhexanediol, 3-methylhexanediol, 2-methylheptanediol, 3-methylheptanediol, and 4-methylheptane. Examples include diol, 2-methyloctanediol, 3-methyloctanediol, and 4-methyloctanediol.
Examples of the branched alkylene diol include 2-methylpentanediol, 3-methylpentanediol, 2-methylhexanediol, 3-methylhexanediol, 2-methylheptanediol, 3-methylheptanediol, and 4-methylheptanediol. 2-methyloctanediol, 3-methyloctanediol, 4-methyloctanediol and the like.
Of these, tetramethylene diol, pentamethylene diol, hexamethylene diol, and nonamethylene diol are preferable for the straight chain, and 3-methyl-1,5-pentanediol, 2-methyl-1,8- for the branched chain. Octanediol is preferred.

Examples of the polycarbonate diol include crystalline polycarbonate diol and amorphous polycarbonate diol.
Examples of the crystalline polycarbonate diol include “Duranol T6002” (manufactured by Asahi Kasei Chemicals Co., Ltd.), “ETERARNACOLL UH-200” (manufactured by Ube Industries, Ltd.), “Nipporan-980R” (manufactured by Nippon Polyurethane Co., Ltd.), “Plaxel CD220” (manufactured by Daicel Corporation) is exemplified.
Examples of the amorphous polycarbonate diol include “PCDL T4672” (manufactured by Asahi Kasei Chemicals Corporation), “PCDL T5652” (manufactured by Asahi Kasei Chemicals Corporation), “Kuraray Polyol C-2090” (manufactured by Kuraray Co., Ltd.), and the like. Can be mentioned.

Examples of the polyether polyol include aliphatic polyether polyols and aromatic ring-containing polyether polyols.
Examples of the aliphatic polyether polyol include aliphatic low-molecular-weight active hydrogen atom-containing compounds (divalent to octavalent or higher aliphatic polyhydric alcohols having a hydroxyl group equivalent of 30 to less than 150 and primary groups as active hydrogen atom-containing groups. Alternatively, an adduct of alkylene oxide (hereinafter abbreviated as AO) of a compound containing a secondary amino group can be used.

  Examples of the aliphatic polyhydric alcohol to which AO is added include linear or branched aliphatic dihydric alcohols [(di) ethylene glycol, (di) propylene glycol, 1,2-, 1,3-, 2 , 3- or 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol and 1,12-dodecanediol, etc.] and alicyclic dihydric alcohol [low molecular diol having a cyclic group, such as those described in JP-B No. 45-1474], aliphatic trihydric alcohol [glycerin, trimethylolpropane, Trialkanolamine, etc.], aliphatic tetravalent or higher alcohol [pentaerythritol, diglycerin, triglycerin, dipentaerythr Lithol, sorbitol, sorbitan, sorbide, etc.] and the like. These may be used individually by 1 type and may use 2 or more types together.

Examples of the compound containing a primary or secondary amino group to which AO is added include, for example, alkyl (C1-12) amine and (poly) alkylene polyamine (C2-6 alkylene group, alkylene group). The number 1-4, the number 2-5 of a polyamine, etc. are mentioned.
Examples of the aromatic ring-containing polyether polyol include AO addition of an aromatic low-molecular-weight active hydrogen atom-containing compound (a divalent to octavalent or higher phenol having a hydroxyl group equivalent of 30 to less than 150 and an aromatic amine). Such as things.

Examples of the phenols to which AO is added include hydroquinone, catechol, resorcin, bisphenol A, bisphenol S, bisphenol F, and the like.
Examples of the aromatic amine include aniline and phenylenediamine.

  Examples of AO used for the production of the AO adduct include AO having 2 to 12 or more carbon atoms, such as ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1, 2 -, 2,3- or 1,3-butylene oxide, tetrahydrofuran (THF), α-olefin oxide, styrene oxide, epihalohydrin (such as epichlorohydrin) and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the aliphatic polyether polyol include polyoxyethylene polyol [polyethylene glycol (hereinafter abbreviated as PEG)], polyoxypropylene polyol [polypropylene glycol (hereinafter abbreviated as PPG) and the like], polyoxyethylene / propylene polyol, Examples thereof include polytetramethylene ether glycol (hereinafter abbreviated as PTMG). These may be used individually by 1 type and may use 2 or more types together.

  Examples of the aromatic ring-containing polyether polyol include a polyol having a bisphenol skeleton, such as an EO addition product of bisphenol A [an EO2 mol addition product of bisphenol A, an EO4 mol addition product of bisphenol A, and an EO6 addition of bisphenol A. Mole adduct, EO 8 mol adduct of bisphenol A, EO 10 mol adduct of bisphenol A, EO 20 mol adduct of bisphenol A, etc., PO adduct of bisphenol A [PO2 mol adduct of bisphenol A, PO3 mol of bisphenol A Adducts, PO5 molar adducts of bisphenol A, etc.], EO or PO adducts of resorcin, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of other condensation polymer polyols include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, poly Butylene hexamethylene adipate diol, polydiethylene adipate diol, poly (polytetramethylene ether) adipate diol, poly (3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene Sebacate diol, polyneopentyl terephthalate diol, etc. It is below. These may be used individually by 1 type and may use 2 or more types together.

-Nonionic short chain polyhydric alcohol-
Examples of the nonionic short chain polyhydric alcohol include polyhydric alcohols having 2 to 15 carbon atoms [dihydric alcohols (for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol). , Neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol, diethylene glycol, etc.); trihydric alcohols (for example, glycerin, trimethylolpropane, etc.); these polyhydric alcohols EO and / or PO low molar adducts (number average molecular weight (Mn) less than 400), etc.]. These may be used individually by 1 type and may use 2 or more types together.

-Ionic short-chain polyhydric alcohol-
As the ionic short chain polyhydric alcohol, for example, a dialkylol alkanoic acid having 6 to 24 carbon atoms can be used. For example, 2,2-dimethylolpropionic acid (abbreviated as DMPA), 2,2-dimethylol. Butanoic acid, 2,2-dimethylolheptanoic acid, 2,2-dimethyloloctanoic acid, or salts thereof such as salts of amines (for example, triethylamine, alkanolamine, morpholine, etc.) and / or alkali metal salts ( Sodium salt). These may be used individually by 1 type and may use 2 or more types together.

-Polyisocyanate-
The polyisocyanate has two or more isocyanate groups, an aromatic polyisocyanate having 6 to 20 carbon atoms (excluding carbon in the isocyanate group, the same shall apply hereinafter), an aliphatic polyisocyanate having 2 to 18 carbon atoms, Examples thereof include alicyclic polyisocyanates having 4 to 15 carbon atoms, araliphatic polyisocyanates having 8 to 15 carbon atoms, and modified products of these polyisocyanates. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the aromatic polyisocyanate having 6 to 20 carbon atoms include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 4,4. '-Or 2,4'-diphenylmethane diisocyanate (MDI), crude MDI [crude diaminophenylmethane [condensation product of formaldehyde and aromatic amine (aniline) or a mixture thereof; diaminodiphenylmethane and a small amount (for example, 5% to 20%) %) Of tri- or higher functional polyamine]]: phosgenated product: polyaryl polyisocyanate (PAPI)], 4,4′-diisocyanatobiphenyl, 3,3′methyl-4,4′-diisocyanatobiphenyl 3,3′-dimethyl-4,4′-diisocyanatodiphenylmethane, 1,5 Examples thereof include naphthylene diisocyanate, 4,4 ′, 4 ″ -triphenylmethane triisocyanate, m- or p-isocyanatophenylsulfonyl isocyanate, and these may be used alone or in combination of two or more. May be used in combination.

  Examples of the aliphatic polyisocyanate having 2 to 18 carbon atoms include tylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4- Trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-di Examples include isocyanatohexanoate. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the alicyclic polyisocyanate having 4 to 15 carbon atoms include isophorone diisocyanate (IPDI), 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), Examples thereof include bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- or 2,6-norbornene diisocyanate (NBDI).

  Examples of the araliphatic polyisocyanate having 8 to 15 carbon atoms include m- or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), and the like. It is done.

  Examples of the modified polyisocyanate include modified polyisocyanate (urethane group, carbodiimide group, allophanate group, urea group, burette group, uretdione group, uretoimine group, isocyanurate group and / or oxazolidone group-containing modified product) A free isocyanate group content is usually 8 to 33%, preferably 10 to 30%, particularly 12 to 29%), for example, modified MDI (urethane modified MDI, carbodiimide modified MDI, trihydrocarbyl phosphate modified MDI, etc.), urethane Examples include modified polyisocyanates such as modified TDI, biuret-modified HDI, isocyanurate-modified HDI, isocyanurate-modified IPDI, and urethane-modified polyisocyanates [excess polyisocyanate (TDI, MDI, etc.) Reacting the bets Polyols used in the production of free isocyanate-containing prepolymer] obtained include low molecular weight polyols described below. Examples of the combination of two or more types include a combination of modified MDI and urethane-modified TDI (isocyanate-containing prepolymer).

  Among these polyisocyanate components, aliphatic polyisocyanates having 2 to 18 carbon atoms and alicyclic polyisocyanates having 4 to 15 carbon atoms are preferable, alicyclic polyisocyanates having 4 to 15 carbon atoms are more preferable, and isophorone diisocyanate ( IPDI), 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI) and norbornene diisocyanate (NBDI) are particularly preferred.

-Chain extender-
Examples of the chain extender include diamines having 2 to 10 carbon atoms (for example, ethylene diamine, propylene diamine, hexamethylene diamine, isophorone diamine, toluene diamine, piperazine, etc.), and polyalkylene polyamines (for example, diethylene triamine, triethylene). Tetramine, etc.), hydrazine or derivatives thereof (dibasic acid dihydrazide, such as adipic acid dihydrazide, etc.), amino alcohols having 2 to 10 carbon atoms (for example, ethanolamine, diethanolamine, 2-amino-2-methylpropanol, triethanol) Amine) and the like. These may be used individually by 1 type and may use 2 or more types together.

Further, if necessary, a terminator can be used as long as the object of the present invention is not impaired.
Examples of the terminator include monoalcohols having 1 to 8 carbon atoms (methanol, ethanol, isopropanol, cellosolves, carbitols, etc.), monoamines having 1 to 10 carbon atoms (monomethylamine, monoethylamine, monobutylamine). Mono- or dialkylamines such as dibutylamine and monooctylamine; mono- or dialkanolamines such as monoethanolamine, diethanolamine and diisopropanolamine). These may be used individually by 1 type and may use 2 or more types together.

-Method for producing urethane resin particles containing colorant-
The method for producing the urethane resin particles encapsulating the coloring material is not particularly limited and can be appropriately selected according to the purpose. For example, an acetone method, a prepolymer mixing method, a block isocyanate method, a melt dispersion method, Examples include ketimine / ketazine method and solid self-dispersion method. Among these, the acetone method is preferable from the viewpoint of dispersing and encapsulating the coloring material, which is the object of the present invention, and stably obtaining urethane resin particles.
Other methods are not preferred because they have disadvantages such as excessive energy required for production, non-uniform particle shape and impaired film properties, and poor emulsion dispersion stability. In addition, the acetone method having a phase inversion mechanism is preferable in terms of encapsulating the coloring material in the resin. Although referred to as the acetone method, in the present invention, in addition to acetone, ketones such as ethyl methyl ketone, esters, ethers, amides, alcohols and the like can be used alone or in combination.

  As a method for producing urethane resin particles encapsulating the coloring material, (I) a prepolymer having an isocyanate group at the end, which is composed of a polymer polyol, an ionic / nonionic short-chain alcohol, and a polyvalent isocyanate in an acetone solution. A step of synthesizing the polymer, (II) a step of mixing and dispersing the prepolymer solution and the pigment, (III) a step of bringing the resin solution into contact with water to form fine particles, and (IV) an isocyanate group at the end of the prepolymer. And (V) a step of distilling off the solvent from the system, and further comprising other steps as necessary.

-(I) Process-
In the step (I), a prepolymer having an isocyanate group at the terminal consisting of a polymer polyol (A1), an ionic (A2) / nonionic short chain alcohol (A3), and a polyvalent isocyanate (B) in an acetone solution. This is a step of synthesizing a polymer.

The composition ratio [number of equivalents of (B)] / [number of equivalents of (A1) + number of equivalents of (A2) + number of equivalents of (A3)] in the prepolymer synthesis step is 1.05 to 1.40. Preferably, it is 1.10 or more and 1.30 or less. When the composition ratio is 1.05 or more, the strength of the ink film is good, and excellent scratch resistance can be maintained. Further, the solvent resistance is appropriate, and the storage stability of the ink is improved. Further, when it is 1.40 or more, the viscosity of the ink is appropriate, the strength of the ink film is appropriate, and the warp of the film does not occur.
The solvent resistance is not particularly limited, and any conventionally known method can be used, but it is preferable to determine from the degree of swelling by solvent immersion and molecular mobility using pulsed NMR.

The amount of the ionic polyhydric alcohol preferably satisfies the following conditions.
[Number of moles of (A2)] / [number of moles of (A1) + number of moles of (A2) + number of moles of (A3)] is preferably 0.15 or more and 0.45 or less, and 0.2 or more and 0.0. 4 or less is more preferable. When the ratio is 0.15 or more, it has a hydrophilic portion sufficiently, does not cause particle coarsening, and can maintain a desired particle diameter. Further, when the ratio is 0.45 or more, the hydrophilicity is appropriate, the water resistance of the ink film becomes good, and the scratch resistance is improved.

There is no restriction | limiting in particular as solid content density | concentration at the time of the said prepolymer synthesis | combination, Although it can select suitably according to the objective, 50 mass% or more is preferable, and before moving to a next process from a viewpoint of production stability, it is 70. It is preferable to correct to a value arbitrarily set with the upper limit being mass%.
The prepolymerization reaction in the step (I) is preferably 20 ° C to 150 ° C, more preferably 60 ° C to 110 ° C. The reaction time is more preferably 2 hours to 15 hours. The prepolymer preferably has a free NCO group content of 0.1% to 9.0%.

  In the urethanization reaction, a catalyst used in a normal urethane reaction may be used as necessary in order to promote the reaction. Examples of the catalyst include amine catalysts. Examples of the amine catalyst include triethylamine, N-ethylmorpholine, triethylenediamine, and cycloamidines [1,8-diaza-bicyclo [5,4,0] -7-undecene described in US Pat. No. 4,524,104. (San Apro Co., Ltd., DBU) etc.]; Tin-based catalysts such as dibutyltin dilaurate, dioctyltin dilaurate and tin octylate; titanium-based catalysts such as tetrabutyl titanate.

-(II) Process-
The step (II) is a step of mixing and dispersing the prepolymer solution and the color material.
The mixing of the prepolymer solution and the color material in the step (II) is a step necessary for efficiently including the color material in the particles.
A similar emulsion can be obtained even if the elongation reaction of the step (IV) is performed and then dispersed, but there are cases where the aggregate of the coloring material increases and the image quality is lowered.

As a dispersion method in the step (II), for example, a normal mixing and stirring device such as a vibration type / ultrasonic homogenizer, a disper, a rotor / stator (for example, Ebara Milder (manufactured by Ebara Seisakusho)), a static mixer or the like is used. Can be done. In addition, you may pass a media type | mold mill, a roll mill, a microfluidizer, etc. in the range which does not impair the effect of this invention. However, it is preferable to carry out at a temperature of 40 ° C. or lower in order to suppress excessive reaction progress.
The addition amount of the color material is preferably 10 parts by mass or more and 50 parts by mass or less, and 20 parts by mass with respect to 100 parts by mass of the polyurethane resin, from the viewpoint of image density and ease of containing the color material in the polyurethane resin particles. More preferred is at least part and no more than 40 parts by weight.

-(III) Step-
The step (III) is a step of bringing the resin solution and water into contact to form fine particles.
In the atomization in the step (III), it is mixed with water. The mixing method is not particularly limited and may be appropriately selected depending on the intended purpose. For example, water may be added to a resin-pigment-acetone mixture, or the mixture may be added to water. You may mix.
As the mixing apparatus, the same apparatus as in the step (II) can be used, but it is preferable to carry out at a temperature of 40 ° C. or lower in order to suppress excessive reaction progress.
The content of the water is preferably 100 parts by mass to 1,000 parts by mass and more preferably 200 parts by mass to 500 parts by mass with respect to 100 parts by mass of the mixture organic solvent from the viewpoint of making the continuous phase into an aqueous phase. preferable. When mixing a mixture and water, it can carry out using normal mixing stirring apparatuses, such as the above-mentioned homogenizer and a disper.

-(IV) Step-
The step (IV) is a step of reacting an isocyanate group at the end of the prepolymer with a chain extender.
In the step (IV), when the isocyanate group at the end of the prepolymer and the chain extender are reacted, the following conditions are preferably satisfied.
(Equivalent number of chain extender × mass of solid content of prepolymer solution / number of NCO equivalents of prepolymer) is preferably 0.8 or more and 1.05 or less. When the ratio is in the range of 0.8 to 1.05,
The ion balance in the system is appropriate, the storage stability is improved, and the mechanical strength and solvent resistance of the ink film are good.

-(V) Process-
The step (V) is a step of distilling off the solvent from the system.
In the step (V), the method for removing the organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a vacuum distillation method and a thin film vacuum distillation method. Among these, the thin film type vacuum distillation method is preferable. In addition, the removal amount of the organic solvent is not particularly limited, and it is usually preferable that the entire amount of the organic solvent is removed.

-Other processes-
As said other process, you may remove a coarse particle from the aqueous dispersion of a polymer particle by centrifugation, filter filtration, etc. as needed.

  The volume average particle diameter of the urethane resin particles encapsulating the coloring material obtained from the step (I) to the step (V) is 70 nm or more and 300 nm from the viewpoint of prevention of ink bleeding and dispersion stability. It is below, and 70 nm or more and 250 nm or less are preferable.

The content of the urethane resin particles encapsulating the colorant is preferably 5% by mass or more and 30% by mass or less, and preferably 5% by mass or more and 15% by mass or less with respect to the total amount of ink from the viewpoint of image density and ejection stability. More preferred.
When the content is 5% by mass or more, between the urethane resin particles encapsulating the color material and the urethane resin particles encapsulating the color material, and between the urethane resin particle encapsulating the color material and the recording medium Is sufficient, high film strength can be secured, and scratch resistance is good. Further, when the content is 30% by mass or less, it does not cause excessive agglomeration and does not cause warpage in the recorded matter, which is good.

(ink)
Hereinafter, the organic solvent, water, color material, resin, additive, and the like used for the ink will be described.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-he Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol mono Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- -N-containing heterocyclic compounds such as pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, Examples include ethylene carbonate.
In addition to functioning as a wetting agent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because good drying properties can be obtained.

A polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used.
Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a recording medium.

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of the drying property and ejection reliability of the ink, 20 mass% or more and 60 mass% or less are more preferable.

<Water>
The water content in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass to 90% by mass, and preferably 20% by mass from the viewpoint of ink drying properties and ejection reliability. -60 mass% is more preferable.

<Color material>
The color material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used alone or in combination of two or more. A mixed crystal may be used.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy pigment such as gold or silver, a metallic pigment, or the like can be used.
Carbon black produced by known methods such as contact method, furnace method, thermal method in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow as inorganic pigments Can be used.
Organic pigments include azo pigments, polycyclic pigments (eg, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinofullerone pigments). Dye chelates (for example, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black, and the like can be used. Of these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of the pigment include black for carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11). And organic pigments such as metals such as titanium oxide and aniline black (CI Pigment Black 1).
Further, for color use, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, and the like.
The dye is not particularly limited, and an acid dye, a direct dye, a reactive dye, and a basic dye can be used. One kind may be used alone, or two or more kinds may be used in combination.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive black 3, 4, 35 etc. are mentioned.

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, an antirust agent, a pH adjuster, and the like may be added to the ink.

-Surfactant-
As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used.
There is no restriction | limiting in particular in silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as an aqueous surfactant. In addition, as the silicone surfactant, a polyether-modified silicone surfactant can be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the Si portion side chain of dimethylsiloxane.
Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylate. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.
Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
These may be used alone or in combination of two or more.

The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side Since both ends of the chain are modified with polydimethylsiloxane, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant. preferable.
As such a surfactant, an appropriately synthesized product or a commercially available product may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.
The polyether-modified silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples include those introduced into the side chain of the Si part of the polysiloxane.
Formula (S-1)
(In the general formula (S-1), m, n, a, and b represent integers. R and R ′ represent an alkyl group and an alkylene group.)
A commercial item can be used as said polyether modified silicone type surfactant, For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Bic Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain.
Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because of its low foaming property, and particularly fluorine represented by the general formulas (F-1) and (F-2). A surfactant is preferred.
Formula (F-1)
In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
Formula (F-2)
_{C n F 2n + 1- CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y
In the compound represented by the general formula (F-2), Y is H, or CnF _{2n + 1} , n is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ —CnF _{2n + 1,} where n is 4 to 6. An integer, or CpH _{2p + 1} , p is an integer of 1-19. a is an integer of 4-14.
A commercially available product may be used as the fluorosurfactant. Examples of the commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by DIC Corporation); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont) ); FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Li Fox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by OMNOVA Solutions Inc.), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) and the like. Among these, FS-300 manufactured by DuPont, FT-110 manufactured by Neos Co., Ltd., and FT- from the point that good image quality, particularly color developability, paper permeability, wettability, and level dyeability are remarkably improved. 250, FT-251, FT-400S, FT-150, FT-400SW, Omnova's Polyfox PF-151N and Daikin Industries, Ltd.'s Unidyne DSN-403N are particularly preferred.

  There is no restriction | limiting in particular as content of surfactant in an ink, Although it can select suitably according to the objective, From the point which is excellent in wettability and discharge stability, and image quality improves, it is 0.001 mass. % To 5% by mass is preferable, and 0.05% to 5% by mass is more preferable.

-Antifoaming agent-
There is no restriction | limiting in particular as an antifoamer, For example, a silicone type antifoamer, a polyether type | system | group antifoamer, a fatty-acid ester type | system | group antifoamer etc. are mentioned. These may be used alone or in combination of two or more. Among these, a silicone type antifoaming agent is preferable from the viewpoint of excellent foam breaking effect.

-Antiseptic and fungicide-
The antiseptic / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

-Antirust agent-
There is no restriction | limiting in particular as a rust preventive agent, For example, acidic sulfite, sodium thiosulfate, etc. are mentioned.

-PH adjuster-
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

There is no restriction | limiting in particular as a physical property of an ink, According to the objective, it can select suitably, For example, it is preferable that a viscosity, surface tension, pH, etc. are the following ranges.
The viscosity at 25 ° C. of the ink is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less from the viewpoint of improving the printing density and character quality and obtaining good discharge properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. Measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid amount 1.2 mL, rotation speed 50 rpm, and measurement is possible for 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less and more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12 and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

<Recording medium>
The recording medium used for recording is not particularly limited, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.

<Recorded material>
The ink recorded matter of the present invention has an image formed using the ink of the present invention on a recording medium.
Recording can be performed by recording with an inkjet recording apparatus and an inkjet recording method.

(Ink container)
The ink container of the present invention contains the ink of the present invention in a container, and further includes other members appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. What has is mentioned suitably.

(Inkjet recording apparatus, inkjet recording method)
The inkjet recording method of the present invention is an inkjet recording method in which ink is ejected from a nozzle of a recording head and applied to a recording medium for recording.
The ink is the ink of the present invention.
The ink jet recording apparatus of the present invention includes the ink container of the present invention and a recording head for ejecting ink droplets, and further includes other members as necessary.

The ink of the present invention can be suitably used for various recording apparatuses using an ink jet recording method, such as a printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier complex machine, and a three-dimensional modeling apparatus.
In the present invention, the recording apparatus and the recording method are an apparatus capable of ejecting ink, various treatment liquids, and the like to a recording medium, and a method of performing recording using the apparatus. The recording medium means a medium on which ink or various processing liquids can be temporarily attached.
The recording apparatus can include not only a head portion that ejects ink but also means for feeding, transporting, and discharging a recording medium, and other devices called pre-processing devices and post-processing devices. .
The recording apparatus and the recording method may include a heating unit used in the heating step and a drying unit used in the drying step. The heating means and the drying means include, for example, a means for heating and drying the printing surface and the back surface of the recording medium. Although it does not specifically limit as a heating means and a drying means, For example, a warm air heater and an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording apparatus and the recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, what forms patterns, such as a geometric pattern, etc. includes what forms a three-dimensional image.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise specified.
Furthermore, this recording apparatus can use not only a desktop type but also a wide recording apparatus that can print on an A0 size recording medium, for example, a continuous paper wound up in a roll shape as a recording medium. Also included are continuous paper printers.
An example of the recording apparatus will be described with reference to FIGS. FIG. 3 is an explanatory perspective view of the apparatus. FIG. 4 is a perspective view of the main tank. An image forming apparatus 400 as an example of a recording apparatus is a serial type image forming apparatus. A mechanism unit 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink storage portion 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), yellow (Y) is packaged, for example, an aluminum laminate film It is formed by a member. The ink storage unit 411 is stored in, for example, a plastic container case 414. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus main body is opened. A main tank 410 is detachably attached to the cartridge holder 404. Thus, the ink discharge ports 413 of the main tank 410 and the discharge heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and ink can be discharged from the discharge heads 434 to the recording medium.

The recording apparatus can include not only a portion that ejects ink but also a device called a pre-processing device or a post-processing device.
As one mode of the pretreatment device and the posttreatment device, as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), a pretreatment liquid and a posttreatment liquid are included. There is a mode in which a liquid container and a liquid discharge head are added, and a pretreatment liquid and a posttreatment liquid are discharged by an ink jet recording method.
As another aspect of the pretreatment apparatus and the posttreatment apparatus, there is an aspect in which, for example, a pretreatment apparatus or a posttreatment apparatus other than the ink jet recording method is provided by a blade coating method, a roll coating method, or a spray coating method.

  The method of using the ink is not limited to the ink jet recording method, and can be widely used. Besides the ink jet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. Furthermore, it can be used not only to form two-dimensional characters and images using ink, but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional modeled object).
A known three-dimensional modeling apparatus for modeling a three-dimensional model can be used, and is not particularly limited. For example, a three-dimensional modeling apparatus including an ink storage unit, a supply unit, a discharge unit, a drying unit, or the like is used. be able to. The three-dimensional structure includes a three-dimensional structure obtained by repeatedly applying ink. Further, a molded product obtained by processing a structure provided with ink on a substrate such as a recording medium is also included. The molded product is obtained by subjecting a recorded material or a structure formed in a sheet shape or a film shape to a molding process such as heat stretching or punching, for example, an automobile, an OA device, an electric -It is suitably used for applications in which surfaces are decorated after decorating, such as meters for electronic devices, cameras, etc., and panels for operation units.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Preparation Example 1)
-Preparation of urethane resin emulsion A encapsulating cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of an amorphous polycarbonate diol having a number average molecular weight (Mn) of 500 (Duranol T5651, manufactured by Asahi Kasei Chemicals Corporation), 45.8 g of dimethylolpropionic acid, norbornene methane diisocyanate (NBDI) ) (Mitsui Chemical Fine Co., Ltd.) 301 g, triethylamine 29.4 g, and acetone 650 g were charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid concentration of 67% by mass and an NCO% of 0.27%.
Next, after cooling the system to 40 ° C., 263 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a cyan pigment was added stepwise under constant stirring together with the same amount of acetone. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 60% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,630 g of ion-exchanged water was added stepwise into a system stirred at 300 rpm under a nitrogen stream to make fine particles. After the entire amount was added, stirring was performed for 15 minutes. Next, the chain extender, diethylenetriamine, was weighed so that (number of chain extender equivalents × prepolymer solution solids mass / number of NCO equivalents of prepolymer) was 1.0, and it was used as a 10% by weight acetone solution in the system. And a chain elongation reaction was performed by stirring for 5 hours. Thereafter, 10 g of a 50 mass% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. Acetone was removed using an evaporator, and then diluted with water so that the solid content concentration became 30% by mass to obtain urethane resin emulsion A enclosing a cyan pigment.

(Preparation Example 2)
-Preparation of urethane resin emulsion B encapsulating cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of amorphous polycarbonate diol having a number average particle size (Mn) of 500 (Duranol T5651, manufactured by Asahi Kasei Chemicals Corporation), 64.6 g of dimethylolpropionic acid, isophorone diisocyanate (IPDI) ) (Mitsui Chemicals Fine Co., Ltd.) 358 g, triethylamine 34.1 g, and acetone 710 g were charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid concentration of 67% by mass and an NCO% of 0.27%.
Next, after the system was cooled to 40 ° C., 287 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a cyan pigment was added stepwise under constant stirring with the same amount of acetone. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,630 g of ion-exchanged water was added stepwise into a system stirred at 300 rpm under a nitrogen stream to make fine particles. After the entire amount was added, stirring was performed for 15 minutes. Next, isophoronediamine, which is a chain extender, was weighed so that (the number of equivalents of chain extender × the mass of prepolymer solution solids / the number of NCO equivalents of prepolymer) was 0.8, and it was used as a 10% acetone solution in the system. And a chain elongation reaction was performed by stirring for 5 hours. Thereafter, 1 g of a 50% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. Acetone was removed using an evaporator, and then diluted with water so that the solid content concentration was 30% by mass to obtain a urethane resin emulsion B containing a cyan pigment.

(Preparation Example 3)
-Preparation of urethane resin emulsion C encapsulating cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of amorphous polycarbonate diol having a number average molecular weight (Mn) of 1,000 (Duranol T5651, manufactured by Asahi Kasei Chemicals Corporation), 21.7 g of dimethylolpropionic acid, 4,4 -213 g of dicyclohexylmethane diisocyanate (hydrogenated MDI) (manufactured by Tokyo Chemical Industry Co., Ltd.), 11.5 g of triethylamine, and 400 g of acetone were charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid concentration of 64% by mass and an NCO% of 0.89%.
Next, after the system was cooled to 40 ° C., 287 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a cyan pigment was added stepwise under constant stirring with the same amount of acetone. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,630 g of ion-exchanged water was added stepwise into a system stirred at 300 rpm under a nitrogen stream to make fine particles. After the entire amount was added, stirring was performed for 15 minutes. Next, isophorone diamine, which is a chain extender, is weighed so that (number of chain extender equivalents × prepolymer solution solid content mass / number of NCO equivalents of prepolymer) is 1.0, and the system is used as a 10 mass% acetone solution. The solution was put in and stirred as it was for 5 hours to carry out a chain extension reaction. Thereafter, 10 g of a 50 mass% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. Acetone was removed using an evaporator, and then diluted with water so that the solid content concentration became 30% by mass to obtain urethane resin emulsion C enclosing a cyan pigment.

(Preparation Example 4)
-Preparation of urethane resin emulsion D containing cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 250 g of polycaprolactone diol having a number average molecular weight (Mn) of 1,000 (PCL210, manufactured by Daicel Corporation) and polycaprolactone triol having a number average molecular weight (Mn) of 1,000 (PCL312). 250 g, dimethylolpropionic acid 28.3 g, 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI) (manufactured by Tokyo Chemical Industry Co., Ltd.) 249 g, triethylamine 14.9 g, and acetone 430 g, nitrogen Prepared while introducing. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid concentration of 64% by mass and an NCO% of 0.89%.
Next, after cooling the system to 40 ° C., 198 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a cyan pigment was added stepwise with constant stirring under constant stirring. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,470 g of ion-exchanged water was gradually introduced into the system stirred at 300 rpm under a nitrogen stream to make fine particles. After the entire amount was added, stirring was performed for 15 minutes. Next, the chain extender, diethylenetriamine, was weighed so that (number of chain extender equivalents × prepolymer solution solids mass / number of NCO equivalents of prepolymer) was 1.0, and it was used as a 10% by weight acetone solution in the system. And a chain elongation reaction was performed by stirring for 5 hours. Thereafter, 12.8 g of a 50 mass% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. After removing acetone using an evaporator, it was diluted with water so that the solid content concentration was 30% by mass, and a urethane resin emulsion D enclosing a cyan pigment was obtained.

(Preparation Example 5)
-Preparation of urethane resin emulsion containing black pigment-
In Preparation Example 4, Pigment Blue 15: 3 was replaced with Carbon Black (Printex35, manufactured by Dexa, DBP oil absorption = 42 mL / 100 mg, pH = 9.5), in the same manner as Preparation Example 4, A urethane resin emulsion containing a black pigment was obtained.

(Preparation Example 6)
-Preparation of urethane resin emulsion containing magenta pigment-
A polyurethane resin emulsion encapsulating a magenta pigment is obtained in the same manner as in Preparation Example 4 except that the pigment blue 15: 3 is replaced with a magenta pigment (HOSTAPER PIN EB TRANS., Manufactured by Clariant) in Preparation Example 4. It was.

(Preparation Example 7)
-Preparation of urethane resin emulsion E containing cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of amorphous polycarbonate diol having a number average molecular weight (Mn) of 500 (Duranol T5651, manufactured by Asahi Kasei Chemicals Corporation), 64.6 g of dimethylolpropionic acid, 4,4-dicyclohexyl 423 g of methane diisocyanate (hydrogenated MDI) (manufactured by Tokyo Chemical Industry Co., Ltd.), 34.1 g of triethylamine, and 1,020 g of acetone were charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid content of 61% by mass and an NCO% of 1.15%.
Next, after cooling the system to 40 ° C., 255 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a pigment was added stepwise with the same amount of acetone under constant stirring. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,900 g of ion-exchanged water was gradually introduced into the system in which stirring was performed at 300 rpm under a nitrogen stream, and fine particles were formed. After the entire amount was added, stirring was performed for 15 minutes. Next, isophorone diamine, which is a chain extender, is weighed so that (number of chain extender equivalents × prepolymer solution solid content mass / number of NCO equivalents of prepolymer) is 0.9, and the system is used as a 10% by mass acetone solution. The solution was put in and stirred as it was for 5 hours to carry out a chain extension reaction. Thereafter, 30 g of a 50 mass% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. After removing acetone using an evaporator, it was diluted with water so that the solid concentration was 30% by mass, and urethane resin emulsion E enclosing a cyan pigment was obtained.

(Preparation Example 8)
-Preparation of urethane resin emulsion F containing cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of amorphous polycarbonate diol (Duranol T5652, manufactured by Asahi Kasei Chemicals Corporation) with a number average molecular weight (Mn) of 2,000, 15.6 g of dimethylolpropionic acid, 4,4 -94 g of dicyclohexylmethane diisocyanate (hydrogenated MDI) (manufactured by Tokyo Chemical Industry Co., Ltd.), 10.0 g of triethylamine, and 460 g of acetone were charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid content of 72% by mass and an NCO% of 0.59%.
Next, after cooling the system to 40 ° C., 167 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a pigment was added stepwise under constant stirring with the same amount of acetone. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,150 g of ion-exchanged water was gradually introduced into the system stirring at 300 rpm under a nitrogen stream to make fine particles. After the entire amount was added, stirring was performed for 15 minutes. Next, isophorone diamine, which is a chain extender, was weighed so that (number of chain extender equivalents × prepolymer solution solid content mass / number of NCO equivalents of prepolymer) was 0.8, and the system was used as a 10 mass% acetone solution. The solution was put in and stirred as it was for 5 hours to carry out a chain extension reaction. Thereafter, 3.4 g of a 50 mass% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. After removing acetone using an evaporator, it was diluted with water so that the solid content concentration was 30% by mass to obtain a urethane resin emulsion F containing a cyan pigment.

(Preparation Example 9)
-Preparation of urethane resin emulsion containing cyan pigment G-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of amorphous polycarbonate diol having a number average particle size (Mn) of 1,000 (Duranol T5651, manufactured by Asahi Kasei Chemicals Corporation), 21.7 g of dimethylolpropionic acid, 4, 182 g of 4-dicyclohexylmethane diisocyanate (hydrogenated MDI) (manufactured by Tokyo Chemical Industry Co., Ltd.), 13.9 g of triethylamine, and 390 g of acetone were charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid content of 72% by mass and an NCO% of 0.40%.
Next, after cooling the system to 40 ° C., 210 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a pigment was added stepwise with constant stirring under constant stirring. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,330 g of ion-exchanged water was gradually introduced into the system stirred at 300 rpm under a nitrogen stream to make fine particles. After the entire amount was added, stirring was performed for 15 minutes. Next, isophorone diamine, which is a chain extender, was weighed so that (number of chain extender equivalents × prepolymer solution solid content mass / number of NCO equivalents of prepolymer) was 0.8, and the system was used as a 10 mass% acetone solution. The solution was put in and stirred as it was for 5 hours to carry out a chain extension reaction. Thereafter, 5.0 g of a 50 mass% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. After removing acetone using an evaporator, it was diluted with water so that the solid content concentration was 30% by mass to obtain a urethane resin emulsion G containing a cyan pigment.

(Preparation Example 10)
-Preparation of urethane resin emulsion H containing cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of amorphous polycarbonate diol (Duranol T5650E, manufactured by Asahi Kasei Chemicals Corporation) having a number average molecular weight (Mn) of 1,000, 91.6 g of dimethylolpropionic acid, 4,4 -Dicyclohexylmethane diisocyanate (hydrogenated MDI) (manufactured by Tokyo Chemical Industry Co., Ltd.) 560 g, triethylamine 73.9 g and acetone 910 g were charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid content of 60% by mass and an NCO% of 0.74%.
Next, after cooling the system to 40 ° C., 300 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a pigment was added stepwise under constant stirring with the same amount of acetone. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 2,280 g of ion-exchanged water was gradually introduced into the system stirring at 300 rpm under a nitrogen stream to make fine particles. After the entire amount was added, stirring was performed for 15 minutes. Next, the chain extender diethylenetriamine was weighed so that (number of chain extender equivalents × solid content mass of prepolymer solution / number of NCO equivalents of prepolymer) was 0.8, and the system was used as a 10% by mass acetone solution. The solution was put in and stirred as it was for 5 hours to carry out a chain extension reaction. Acetone was removed using an evaporator, and then diluted with water so that the solid content concentration was 30% by mass to obtain a urethane resin emulsion H containing a cyan pigment.

(Preparation Example 11)
<Preparation of acrylic resin emulsion containing cyan pigment>
-Preparation of oil phase-
23 g of ethyl acetate, 7 g of pigment blue 15: 3 (HOSTAPER BLUE B4G, manufactured by Clariant) as a cyan pigment, 1 g of Solsperse 32000 (manufactured by Lubrizol) as a pigment dispersant, methyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) ) 1.6 g, 2-ethylhexyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 2 g, diethylene glycol dimethacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.4 g, and then circulate 5 ° C water in the jacket. On the other hand, 5 sets of dispersion at 8,000 rpm for 3 minutes were performed using a homogenizer (manufactured by IKA, Ultra Tarrax homogenizer T25) so that the internal temperature did not exceed 40 ° C.

-Preparation of aqueous phase-
To 50 g of ion-exchanged water, 2 g of polyethylene glycol monomethacrylate (PE200, manufactured by NOF Corporation) and 10 g of polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate (Aqualon BC-2020, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Mix well.

35 g of the pigment dispersion obtained above was added to the aqueous phase, and the internal temperature was 40 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax homogenizer T25) while circulating water at 5 ° C. in the jacket. The dispersion was performed for 5 minutes at 8,000 rpm to obtain an O / W emulsion.
The obtained emulsion was put into a four-necked round bottom flask, and a solution obtained by dissolving 0.1 g of a polymerization initiator (V65, manufactured by Wako Pure Chemical Industries, Ltd.) in 3.1 g of ethyl acetate under constant stirring, After mixing, the mixture was heated to 70 ° C. under a nitrogen stream and reacted for 6 hours. After removing ethyl acetate using an evaporator, it was diluted with ion-exchanged water so that the solid content concentration was 30% by mass to obtain an acrylic resin emulsion containing a cyan pigment.

(Preparation Example 12)
-Preparation of urethane resin emulsion I containing cyan pigment-
In an autoclave reactor equipped with a stirrer and a jacket, 500 g of amorphous polycarbonate diol (Duranol T5651, manufactured by Asahi Kasei Chemicals) with a number average molecular weight (Mn) of 1,000, dimethylolpropionic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) ) 30.7 g, 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI) (manufactured by Tokyo Chemical Industry Co., Ltd.) 218 g, triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 16.2 g, and acetone (manufactured by Tokyo Chemical Industry Co., Ltd.) 571 g was charged while introducing nitrogen. Then, it heated at 80 degreeC and urethanation reaction was performed over 5 hours, and the prepolymer was manufactured. The obtained prepolymer had a solid concentration of 62% by mass and an NCO% of 0.89%.
Next, after cooling the system to 40 ° C., 255 g of Pigment Blue 15: 3 (HOSTAPERM BLUE B4G, manufactured by Clariant) as a pigment was added stepwise with the same amount of acetone under constant stirring. This slurry was subjected to ultrasonic treatment for 5 minutes before charging. After the total amount was added, while circulating water at 5 ° C through the jacket, using a homogenizer (IKA, Ultra Turrax homogenizer T25) as a stirrer under a nitrogen stream, the internal temperature should not exceed 40 ° C. Five sets of dispersion and mixing for 3 minutes at 8,000 rpm were performed. Acetone was added so that the solid content concentration was 65% by mass, and normal stirring was performed for 30 minutes.
Next, after returning the system to 40 ° C., 1,900 g of ion-exchanged water was gradually introduced into the system in which stirring was performed at 300 rpm under a nitrogen stream, and fine particles were formed. After the entire amount was added, stirring was performed for 15 minutes. Next, the chain extender diethylenetriamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was weighed so that (number of chain extenders equivalent number × prepolymer solution solid content mass / number of NCO equivalents of prepolymer) was 1.0, A 10% by mass acetone solution was added to the system, and the mixture was stirred for 5 hours to carry out a chain extension reaction. Thereafter, 17.2 g of a 50 mass% acetone solution of triethylamine was added, and the mixture was further stirred for 1 hour. Acetone was removed using an evaporator, and then diluted with water so that the solid content concentration was 30% by mass to obtain a urethane resin emulsion I including a cyan pigment.

Example 1
-Preparation of ink-
The following ink formulation was mixed, stirred for 1.5 hours, and then filtered through a membrane filter having an average pore size of 0.8 μm to prepare an ink.
[Ink prescription]
2,3-butanediol (bp: 183 ° C.) 20.0 parts by mass Ethylene glycol n-hexyl ether (bp: 208 ° C.) 15.0 parts by mass Silanol-modified polyvinyl alcohol (Kuraray Co., Ltd.) Manufactured, R-1130) ... 1.0 part by mass Surfactant: CH ₃ (CH ₂ ) ₁₂ O (CH ₂ CH ₂ O) ₃ CH ₂ COOH ... 2.0 parts by mass Agent (Proxel LV, manufactured by Avicia) ... 0.1 parts by mass-Polyurethane resin emulsion A containing the cyan pigment of Preparation Example 1 ... 29.0 parts by mass-Ion-exchanged water--Remaining amount (total) : 100 parts by mass)

(Examples 2-6 and Comparative Examples 1-6)
-Preparation of ink-
In Example 1, except that the urethane resin emulsion A encapsulating the cyan pigment was replaced with a resin emulsion encapsulating the pigment shown in Tables 1 to 4, Examples 2 to 6 and the comparison were made in the same manner as in Example 1. Inks of Examples 1-6 were prepared.

  Next, various characteristics of the inks of Examples 1 to 6 and Comparative Examples 1 to 6 were evaluated as follows. The results are shown in Tables 1 to 4.

<Measurement of volume average particle diameter>
Each ink was diluted with ion-exchanged water so that the solid content concentration was 0.5% by mass, and then ELSZ-1000 manufactured by Otsuka Electronics Co., Ltd. was used. (Maximum value 50,000, minimum value 10,000), pinhole 50, dust cut tolerance is measured as 5%, analyzed by Marquart method, volume average particle diameter of pigment-encapsulated urethane resin particles in ink Asked.

<Measurement of breaking energy>
4 g of each ink was put in a Teflon (registered trademark) petri dish having a diameter of 50 mm, and vacuum degassing was performed for 1 minute while paying attention to the overflow of ink due to foaming in a suction filtration bell. Then, the ink film was obtained by drying for 1 week in a hot air circulating thermostat at 40 ° C. Using the autograph AG-10N manufactured by Shimadzu Corporation, the obtained ink film is subjected to a tensile test under the conditions of load cell: 50 N, tensile speed: 1.5 mm / min, chuck distance of 6 mm, and sample width of 2 mm. The breaking energy was obtained. In addition, the sample thickness measured 3 points | pieces or more between chuck | zippers with the micrometer for every sample, and used the average value.

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) was measured as follows using a differential scanning calorimeter (TA-60WS and DSC-60, manufactured by Shimadzu Corporation).
First, 5.0 mg of an ink film produced in the same manner as the measurement of the breaking energy was placed in an aluminum sample container, and the sample container was placed on a holder unit and set in an electric furnace. Next, the temperature was raised from 0 ° C. to 150 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, and then the temperature was lowered from 150 ° C. to −80 ° C. at a temperature lowering rate of 5 ° C./min. The DSC curve was measured by raising the temperature to 150 ° C./min. From the obtained DSC curve, using the analysis program in the DSC-60 system, the inflection part at the second temperature rise was analyzed by the midpoint method, and the glass transition temperature (Tg) was obtained.

<Evaluation of dispersion stability>
After each ink is filled in an ink cartridge and stored at 70 ° C. for 2 weeks, the change rate of the viscosity is obtained from the following equation from the ink after storage that is left overnight at 25 ° C. and the ink viscosity before storage. The evaluation was made according to the following criteria.
Viscosity change rate (%) = [(ink viscosity after storage−ink viscosity before storage) / ink viscosity before storage] × 100
The viscosity is measured using a viscometer (RE500L, manufactured by Toki Sangyo Co., Ltd.), adjusted to 50 or 100 rotations according to the viscosity of the sample, measured at 25 ° C., and based on the following criteria: evaluated. C and above are practical.
[Evaluation criteria]
A: Change rate of viscosity is within ± 5% B: Change rate of viscosity is over ± 5% and within ± 8% C: Change rate of viscosity is over ± 8% and within ± 10% D: Change rate of viscosity is Over ± 10% and within ± 30% E: Viscosity change rate exceeds ± 30% (cannot be evaluated due to gelation)

<Image density>
64 point character JIS X 0208 (1997) created by Microsoft Word 2000 (manufactured by Microsoft) by filling each ink prepared in an ink jet printer (IPSiO GX5000, manufactured by Ricoh Co., Ltd.) under an environment of 23 ° C. and 50% RH. , 2223 are printed on plain paper 1 (XEROX 4200, manufactured by XEROX) and plain paper 2 (MyPaper, manufactured by Ricoh Co., Ltd.), and JIS X 0208 (1997), 2223 on the printing surface is printed. The color of the general symbol part was measured using X-Rite 938 (manufactured by X-Rite) and judged according to the following criteria.
The printing mode used was a driver attached to the printer, in which the “plain paper-standard fast” mode was changed to “no color correction” from the user setting for plain paper. C and above are practical.
[Evaluation criteria]
A: 1.05 or more B: 0.95 or more and less than 1.05 C: 0.85 or more and less than 0.95 D: Less than 0.85 E: The pigment is gelled and cannot be dispersed in the ink and cannot be printed.

<Abrasion resistance>
In an environment adjusted to a temperature of 24 ± 0.5 ° C. and humidity of 50 ± 5% RH, each ink is filled and an ink jet printer (IPSiO GX3000, manufactured by Ricoh Co., Ltd.) is used so that the amount of ink discharged is uniform. The solid-state image was printed at a resolution of 600 dpi on TyPe6200 paper (manufactured by NBS Ricoh Co., Ltd.). After the printing was dried, the printed portion was rubbed 10 times with a cotton cloth, and the transfer of the pigment onto the cotton cloth was visually observed and evaluated according to the following criteria. The range up to ○ is an allowable range.
[Evaluation criteria]
◎: Pigment transfer to cotton cloth is not seen at all ○: Pigment transfer to cotton cloth is slightly seen △: Apparent pigment transfer to cotton cloth is seen ×: Significant pigment transfer to cotton cloth is seen Be

From the results of Tables 1 to 4, Examples 1 to 6 are superior in dispersion stability of ink as compared with Comparative Examples 1 to 6, a high image density is obtained even with plain paper, and scratch resistance. It was found that an excellent image can be formed.
On the other hand, in Comparative Example 1, since the volume average particle diameter of the urethane resin particles encapsulating the coloring material in the ink is as small as 60 nm, the dispersion stability of the ink is inferior and the breaking energy of the ink film is low. It was.
In Comparative Examples 2 and 3, the volume average particle diameter of the urethane resin particles encapsulating the coloring material in the ink was appropriate and excellent in the dispersion stability of the ink, but the breaking energy of the ink film was small, The scratch resistance was poor.
Further, in Comparative Example 4, since the breaking energy of the ink film was too high, liquid bending at the time of ejection due to aggregation of urethane resin particles, warping of the image, etc. occurred, and the image density and scratch resistance could not be evaluated.
In Comparative Example 5, an attempt was made to encapsulate a color material with an acrylic resin emulsion, but the dispersion stability was poor, probably due to poor compatibility with the solvent in the ink, and storage at 70 ° C. for 2 weeks. Gelation occurred during the acceleration test. Also, the image density and scratch resistance were poor.
In Comparative Example 6, the volume average particle diameter of the urethane resin particles encapsulating the coloring material in the ink exceeds the upper limit, and partial sedimentation was observed during a storage acceleration test at 70 ° C. for 2 weeks. Ink dispersion stability was poor.

Aspects of the present invention are as follows, for example.
<1> An ink containing urethane resin particles containing water, an organic solvent, and a coloring material,
The volume average particle diameter of the urethane resin particles encapsulating the coloring material by a dynamic light scattering method is 70 nm or more and 300 nm or less,
The ink is characterized in that the breaking energy of the ink film obtained by drying the ink is 20 mJ or more and 200 mJ or less.
<2> The ink according to <1>, wherein the urethane resin particles encapsulating the color material have a volume average particle diameter of 100 nm or more and 250 nm or less by a dynamic light scattering method.
<3> The ink according to any one of <1> to <2>, wherein the ink film obtained by drying the ink has a breaking energy of 50 mJ or more and 200 mJ or less.
<4> The ink according to any one of <1> to <3>, wherein a glass transition temperature of the ink film is 20 ° C. or lower.
<5> The ink according to any one of <1> to <4>, wherein an absolute value of a zeta (ζ) potential is 40 mV or more.
<6> The ink according to <5>, wherein the absolute value of the zeta (ζ) potential is 70 mV or more.
<7> The ink according to any one of <1> to <6>, wherein the urethane resin particles including the coloring material are self-emulsifying type having a hydrophilic group on a surface thereof.
<8> The ink according to any one of <1> to <7>, wherein the urethane resin particles including the coloring material are self-emulsifying type having an anionic group on a surface thereof.
<9> The ink according to <8>, wherein the anionic group is at least one selected from a carboxyl group, a carboxylate group, a sulfonic acid group, and a sulfonic acid group.
<10> The ink according to any one of <1> to <9>, wherein the urethane resin particles including the coloring material have a structure derived from an alicyclic polyisocyanate compound.
<11> The ink according to <10>, wherein the alicyclic polyisocyanate compound is any one of isophorone diisocyanate, norbornenemethane diisocyanate, and 4,4′-dicyclohexylmethane diisocyanate.
<12> The ink according to any one of <1> to <11>, wherein the color material in the urethane resin particles including the color material is either a dye or a pigment.
<13> The ink according to any one of <1> to <12>, wherein the color material in the urethane resin particles including the color material is a pigment.
<14> The ink according to any one of <1> to <13>, wherein the color material in the urethane resin particles encapsulating the color material forms particles by randomly mixing the color material and the polyurethane resin. It is.
<15> Any one of <1> to <14>, wherein a content of the color material in the urethane resin particles including the color material is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polyurethane resin. Ink.
<16> The ink according to any one of <1> to <15>, wherein the content of the urethane resin particles including the coloring material is 1% by mass to 30% by mass.
<17> An ink storage container comprising an ink storage unit storing the ink according to any one of <1> to <16>.
<18> In an ink jet recording method in which ink is ejected from a nozzle of a recording head and applied to a recording medium for recording.
The ink-jet recording method according to any one of <1> to <16>.
<19> An ink jet recording apparatus comprising: the ink container according to <17>; and a recording head for ejecting ink droplets.
<20> A recorded matter comprising an image formed using the ink according to any one of <1> to <16> on a recording medium.

  <1> to <16>, the ink cartridge according to <17>, the ink jet recording method according to <18>, the ink jet recording apparatus according to <19>, and the above According to the ink recorded matter described in <20>, the conventional problems can be solved and the object of the invention can be achieved.

JP-A-1-30176 Japanese Patent Publication No. 5-64724 JP-A-62-95366 JP-A-1-170672 JP-A-5-39447 Japanese Patent Laid-Open No. 10-140065

Claims (11)

An ink containing urethane resin particles containing water, an organic solvent, and a coloring material,
The volume average particle diameter of the urethane resin particles encapsulating the coloring material by a dynamic light scattering method is 70 nm or more and 300 nm or less,
An ink characterized in that the breaking energy of an ink film obtained by drying the ink is 20 mJ or more and 200 mJ or less.   The ink according to claim 1, wherein the glass transition temperature of the ink film is 20 ° C. or less.   The ink according to claim 1, wherein the absolute value of the zeta (ζ) potential is 40 mV or more.   The ink according to any one of claims 1 to 3, wherein the urethane resin particles encapsulating the coloring material are of a self-emulsifying type having a hydrophilic group on the surface.   The ink according to any one of claims 1 to 4, wherein the urethane resin particles containing the coloring material have a structure derived from an alicyclic polyisocyanate compound.   The ink according to any one of claims 1 to 5, wherein the content of the urethane resin particles encapsulating the coloring material is 5% by mass or more and 30% by mass or less.   The ink according to any one of claims 1 to 6, wherein the color material in the urethane resin particles encapsulating the color material is a pigment.   An ink storage container comprising an ink storage unit that stores the ink according to claim 1. In an ink jet recording method in which ink is ejected from a nozzle of a recording head and applied to a recording medium for recording.
An ink jet recording method, wherein the ink is the ink according to claim 1.   An ink jet recording apparatus comprising: the ink container according to claim 8; and a recording head for discharging ink droplets. A recorded matter comprising an image formed using the ink according to any one of claims 1 to 7 on a recording medium.