JP2017218578A - Ink, inkjet recording method, ink cartridge and image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink having high dispersion stability, concealing property and solvent resistance.SOLUTION: An ink includes a volatile solvent, an inorganic hollow particle and a calcium ion. An amount of the calcium ion in the ink is 0.5-250 ppm. The inorganic hollow particle has a 50% cumulative volume particle diameter of 50-350 nm.SELECTED DRAWING: Figure 1

Description

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

Ink jet printers have advantages such as low noise, low running cost, and easy color printing, and are therefore widely used as digital signal output devices in general households. In recent years, it is used not only for home use but also for industrial use such as a display, a poster, and a bulletin board.
However, in the case of industrial use, the recording medium is not limited to paper, but varies widely from transparent to colored. When expressing white on these media or coloring with color ink, it is necessary to conceal the transparency of the recording medium with ink or to sufficiently conceal the color of the recording medium with ink. Therefore, white ink is used to make such a transparent medium or colored medium white. When color ink is used, it is shared with the color ink used for general images, so that white color is printed on the recording medium as the background of the color ink to improve color development.
As a pigment for white ink, titanium dioxide, which is a white pigment excellent in hiding power and coloring power, is widely used. In order to scatter visible light in order to obtain a high hiding power using titanium dioxide, it is necessary to disperse in a particle size range of approximately 200 nm to 300 nm. However, since titanium dioxide has a higher specific gravity than ink media, it tends to settle, and the sedimentation speed becomes faster in low-viscosity inks such as water-based inks and solvent-based inks. Further, when titanium dioxide settles, it is difficult to disperse again in order to form a close packed structure.

In response to such problems, inks using hollow particles have been reported. The hollow particles have an ink medium in the pores in the ink, so that the apparent specific gravity is reduced, and the hollow particles are difficult to settle. The hiding property of the hollow particles can be obtained by utilizing the difference in refractive index between the hollow shell after drying the coating film and the pores from which the ink component has been removed.
For example, Patent Document 1 proposes an ink containing white hollow particles. However, since the white hollow particles described are based on a resin such as styrene, the solvent resistance is poor, and when the ink component contains a highly soluble solvent or depending on the drying conditions after printing, a hollow structure may be formed. It cannot be maintained and transparency occurs, and the desired concealing property cannot be obtained.
Patent Document 2 proposes a radiation curable ink containing inorganic or inorganic / organic mixed hollow particles as a white pigment. However, in the case of curable ink, the desired concealability cannot be obtained because the polymerizable component remains cured in the pores of the hollow particles.
Patent Document 3 proposes an ink containing organic particles having a hollow structure and inorganic particles having a hollow structure. However, as in Patent Document 1, the organic particles having a hollow structure have poor solvent resistance, and the hollow structure cannot be maintained depending on the case where the ink component contains a highly soluble solvent or depending on the drying conditions after printing. Transparency occurs and the desired concealing property cannot be obtained.

  An object of the present invention is to provide an ink having high dispersion stability, hiding properties, and solvent resistance.

The above problem is solved by the following configuration (1).
(1) An ink containing a volatile solvent, inorganic hollow particles and calcium ions, wherein the amount of calcium ions in the ink is 0.5 ppm or more and 250 ppm or less, and the 50% cumulative volume particle size of the inorganic hollow particles The ink is characterized in that it is 50 nm or more and 350 nm or less.

  According to the present invention, an ink having high dispersion stability, concealment and solvent resistance is provided.

FIG. 3 is a perspective view illustrating a recording apparatus. It is a perspective view of a main tank. It is the schematic which shows an example of the ink cartridge of this invention. FIG. 4 is a schematic diagram illustrating a modified example of the ink cartridge of FIG. 3.

The present invention relates to the ink-jet ink shown in the following (1), and embodiments of the invention include the following (2) to (11).
(1) An ink containing a volatile solvent, inorganic hollow particles and calcium ions, wherein the amount of calcium ions in the ink is 0.5 ppm or more and 250 ppm or less, and the 50% cumulative volume particle size of the inorganic hollow particles The ink is characterized in that it is 50 nm or more and 350 nm or less.
(2) The ink according to (1), wherein the calcium ion amount is 0.5 ppm or more and 50 ppm or less.
(3) The ink according to (2), wherein the calcium ion amount is 0.5 ppm or more and 30 ppm or less.
(4) The ink according to any one of (1) to (3), wherein the volatile solvent is a non-polymerizable solvent and has a boiling point of 260 ° C. or lower.
(5) The ink according to any one of (1) to (4), wherein the volatile solvent is water or a water-soluble organic solvent.
(6) The ink according to any one of (1) to (4), wherein the volatile solvent is an organic solvent.
(7) The ink according to any one of (1) to (6), wherein the inorganic hollow particles have a shell thickness of 4 nm or more and 20 nm or less.
(8) When a solid image of 50 mm × 50 mm formed on a polyethylene terephthalate (PET) film is dried in a thermostatic bath at 50 ° C. for 1 hour, the brightness is L * 50 ° C., when dried in a thermostatic bath at 100 ° C. for 1 hour. The ink according to any one of (1) to (7), wherein the absolute value of the brightness difference ΔL * represented by the following formula (1) is 10 or less when the brightness is L * 100 ° C. .
ΔL * = (L * 100 ° C.) − (L * 50 ° C.) (1)
(9) In an ink jet recording method in which the ink according to any one of (1) to (8) is recorded on a recording medium by an ink jet method and includes a drying step after recording, the temperature of the drying step is 50 ° C. The ink jet recording method, wherein the temperature is 200 ° C. or lower.
(10) An ink cartridge comprising the inkjet ink according to any one of (1) to (8).
(11) An image recording apparatus including an ink cartridge containing ink and a recording head for discharging ink, wherein the ink is the ink according to any one of (1) to (8). An image recording apparatus of the type.

  The ink used in the present invention includes a volatile solvent, inorganic hollow particles, and calcium ions. The amount of calcium ions in the ink is 0.5 ppm or more and 250 ppm or less, and 50% cumulative volume particles of the inorganic hollow particles. The diameter is 50 nm or more and 350 nm or less. By using inorganic hollow particles in which the amount of calcium ions in the ink and the 50% cumulative volume particle size in the ink satisfy the above range, an ink having high dispersion stability, concealment and solvent resistance can be obtained.

<Inorganic hollow particles>
Although it does not specifically limit as said inorganic hollow particle, For example, oxides, nitride, oxynitride, etc., such as titanium, silicon, aluminum, a zirconium, and strontium, can be utilized. Titanium oxide is preferable from the viewpoint of the concealability of the coating film. However, in the case of hollow particles, in addition to scattering of the particle surface, scattering of the shell corresponding to the outline of the hollow particles and the internal vacancies can be obtained. Other materials can also be utilized. In addition, from the viewpoint of sedimentation in the ink, it is preferable to use silicon oxide having a small specific gravity as the inorganic hollow particles, and silicon oxide controls the thickness of the shell of the hollow particles (shell thickness) and the pore diameter. Is relatively easy. Therefore, the inorganic hollow particles are preferably silicon oxide.

  The inorganic hollow particles preferably have a specific gravity close to the specific gravity of the ink liquid so that they do not precipitate, float or separate in the ink, and therefore the shell thickness of the inorganic hollow particles is preferably 4 nm or more and 20 nm or less, preferably 6 nm or more. More preferably, it is 18 nm or less. When the shell thickness is 4 nm or more, collapse of the hollow structure due to energy loaded in the dispersion process is prevented, high concealability is obtained, and sedimentation in the ink is also prevented. When the shell thickness is 20 nm or less, the specific gravity as the inorganic hollow particles can be kept small, and settling in the ink is prevented. The ratio (inner diameter / outer diameter) of the inner diameter (hole diameter) and the outer diameter (primary particle diameter) of the inorganic hollow particles is preferably 0.75 or more and 0.95 or less. When the ratio is 0.75 or more, sufficient scattering of the hollow shell and the internal vacancies can be obtained, high concealing property can be obtained, and the internal vacancies make it difficult to settle, and it is 0.95 or less. The strength of the hollow shell can be obtained, the structure can be maintained even under the energy load at the time of dispersion, and high concealability and high dispersion stability that is difficult to settle are obtained.

  The number average primary particle diameter of the inorganic hollow particles is preferably 20 nm or more and less than 200 nm. When the number average primary particle is 20 nm or more, the concealing property of the coating film can be ensured by scattering of the hollow shell and the internal pores. When the number average primary particle is less than 200 nm, it is difficult to settle in the ink and high dispersion stability. Can be expected. When the number average primary particle diameter of the inorganic hollow particles is 50 nm or more and 100 nm or less, the effect of enhancing the concealing property and the high dispersion stability are preferably achieved. The number primary average particle diameter and the shell thickness are primary particles of 200 to 500 primary particles in a 30,000-fold field of view using a transmission electron microscope (manufactured by JEOL, "JEM-2100F"). The diameter in a certain direction at the interval between two parallel lines in a certain direction sandwiching the particles can be measured and obtained from the average value of the cumulative distribution.

  The 50% cumulative volume particle diameter (D50) of the inorganic hollow particles in the ink is 50 nm or more and 350 nm or less. Furthermore, it is preferably 68 nm or more and 350 nm or less, and more preferably 80 nm or more and 260 nm or less. When the 50% cumulative volume particle size (D50) is 50 nm or more, it is possible to obtain a concealing property of the coating film, and when it is 350 nm or less, an increase in apparent specific gravity due to the constraining solvent between the particles due to secondary aggregation. It can be suppressed, and it is difficult to settle and high dispersion stability can be obtained. The 50% cumulative volume particle diameter (D50) of the ink composition described here is the secondary particle diameter in the ink composition, and when this value satisfies the above, the effect of the present invention can be obtained. it can. The 50% cumulative volume particle size (D50) is, for example, diluted 100 to 1000 times with a volatile solvent using ink as a dispersion medium, and a particle size distribution meter (manufactured by Nikkiso, “UPA-150EX”) Can be measured. Further, the 50% cumulative volume particle size (D50) of the ink means the 50% cumulative volume particle size (D50) obtained by subjecting the ink itself to the measurement. Corresponds to a 50% cumulative volume particle size (D50) of the dispersion containing inorganic hollow particles.

  The content of the inorganic hollow particles in the ink is preferably 3% by mass or more and 12% by mass or less, and more preferably 4.5% by mass or more and 10% by mass or more. When it is 3% by mass or more, sufficient concealing property and scratch resistance are obtained, and when it is 12% by mass or less, a sufficient coating film concentration can be obtained and good ejection stability can be obtained.

  When the inorganic hollow particles are made of silicon oxide (hereinafter sometimes referred to as hollow silica particles), the production method is not particularly limited, but may be a known production method. For example, as described in Japanese Patent Nos. 4654428 and 5810362, silica is obtained by forming an alkoxysilane on the surface of calcium carbonate in the presence of a basic catalyst using calcium carbonate as a core material. Thereafter, hollow silica particles can be obtained by a method of dissolving calcium carbonate by acid addition. In this calcium carbonate dissolution step, it is possible to obtain hollow silica particles with little secondary aggregation by controlling the pH. Specifically, it is to avoid the isoelectric point of silica. Since silica has an isoelectric point in the vicinity of pH 2 to 3, if the pH is lowered too much when calcium carbonate is dissolved, the electrostatic repulsive force is lost and aggregates. Therefore, when dissolving calcium carbonate, the pH is preferably between 4 and 5.

In the present invention, the amount of calcium ions in the ink needs to be 0.5 ppm or more and 250 ppm or less, preferably 0.5 ppm or more and 50 ppm or less, and more preferably 0.5 ppm or more and 30 ppm or less. If it is less than 0.5 ppm, the efficiency of the purification process is significantly reduced. If the amount of calcium ions in the ink exceeds 250 ppm, it is not possible to satisfy all of the dispersion stability, hiding property and solvent resistance.
The amount of calcium ions in the ink can be quantified using an ICP emission spectroscopic analyzer (ICPE-9000, manufactured by Shimadzu Corporation). The amount of calcium ions varies depending on the number of times of passing through the ultrafiltration membrane at the manufacturing stage.

  When using hollow silica particles in the ink used in the present invention, it is preferable to use a dispersion of hollow silica particles produced in the process of producing hollow silica particles, rather than powder-dried hollow silica particles. By using a dispersion of hollow silica particles, it is possible to prevent strong interparticle aggregation during drying, and a hollow structure even within the range of 50% cumulative volume particle diameter (D50) of inorganic hollow particles defined in the present invention. It is possible to disperse again in the ink while maintaining the above.

  When using hollow silica particles, the amount of calcium ions in the ink depends on the amount of acid when dissolving the core particles in the particle production process. The use of other inorganic hollow particles also depends on the production conditions.

When dispersing the inorganic hollow particles in the ink, it is desirable to add a dispersant polymer. Examples of the dispersant polymer include an α-olefin-maleic anhydride copolymer, a styrene- (meth) acrylic copolymer, a water-soluble polyurethane resin, and a water-soluble polyester resin. These may be used alone or in combination of two or more. When the dispersant polymer is used, the steric repulsion effect accompanying the adsorption of the dispersant can be improved, and high dispersion stability can be obtained. The dispersant polymer means a polymer having a weight average molecular weight of 1,000 or more.
As content of the said dispersing agent polymer, 10 mass% or more and 60 mass% or less are preferable with respect to an inorganic hollow particle, and 15 mass% or more and 50 mass% or less are more preferable. When the content is 10% by mass or more, dispersibility can be secured by the steric repulsion effect of the dispersant polymer adsorbed on the inorganic hollow particles, and when the content is 60% by mass or less, the dispersion is not adsorbed on the inorganic hollow particles. The amount of the agent polymer is small, and the viscosity of the ink can be reduced. Further, since the amount of the dispersant polymer that is not adsorbed is small, an increase in the thixotropy of the ink is suppressed, and the filtration liquid permeability and the discharge performance are improved.

<Volatile solvent>
The ink of the present invention contains a volatile solvent. The volatile solvent is preferably a non-polymerizable solvent having no polymerizable functional group, and more preferably not remaining in the inorganic hollow particles when the coating film is dried. When the volatile solvent is water or a water-soluble organic solvent, it can be used as a water-based ink, and when the volatile solvent is an organic solvent, it can be used as a solvent ink. However, in recent years, many VOC (volatile organic compound) problems have been taken up, and water-based inks capable of reducing the amount of VOC generation are widely desired. VOC is a general term for organic compounds that easily volatilize in the atmosphere at normal temperature and pressure. The volatile solvent described in the present invention is required to volatilize when heated on a recording medium, and has a boiling point of 300 It means the one below ℃.
As described above, the ink of the present invention can be concealed by utilizing the scattering of the shell of the inorganic hollow particles and the internal pores in addition to the scattering of the particle surface. Therefore, if the ink component remains in the inorganic hollow particles after the coating film is dried, the concealability of the coating film is lowered. From the above points, the volatile solvent preferably has a boiling point of 260 ° C. or lower.

(Water-based ink)
Examples of the water-soluble organic solvent used in the water-based ink include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and the like. Sulfur compounds are mentioned.
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 thereof include ethylene carbonate.
In addition to functioning as a wetting agent, it is preferable to use a water-soluble organic solvent having a boiling point of 260 ° C. or lower because good drying properties can be obtained.

Of these, polyol compounds having 8 or more carbon atoms and glycol ether compounds are preferably used.
Specific examples of preferable polyol compounds 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 preferred glycol ether compounds include polyhydric alcohols 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. Alkyl ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;

  The content of the water-soluble organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose. Preferably, 20 mass% or more and 60 mass% or less are more preferable.

  The content of water in the water-based ink is not particularly limited and may be appropriately selected depending on the intended purpose. A mass% to 60 mass% is more preferable.

(Solvent ink)
Examples of the organic solvent used in the solvent ink include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl. Ether acetate, dipropylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether propionate, ethylene glycol monoethyl ether propionate, ethylene glycol monobutyl ether propionate, diethylene glycol monomethyl ether propionate, diethyl Glycol monoethyl ether propionate, diethylene glycol monobutyl ether propionate, propylene glycol monomethyl ether propionate, dipropylene glycol monomethyl ether propionate, ethylene glycol monomethyl ether butyrate, ethylene glycol monoethyl ether butyrate, ethylene glycol Glycol monoacetates such as monobutyl ether butyrate, diethylene glycol monomethyl ether butyrate, diethylene glycol monoethyl ether butyrate, diethylene glycol monobutyl ether butyrate, propylene glycol monomethyl ether butyrate, dipropylene glycol monomethyl ether butyrate; ethylene glycol diacetate , Diethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, ethylene glycol propionate butyrate, ethylene glycol dipropionate, ethylene glycol acetate dibutyrate, diethylene glycol Acetate propionate, diethylene glycol acetate butyrate, diethylene glycol propionate butyrate, diethylene glycol dipropionate, diethylene glycol acetate dibutyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, propylene glycol propionate butyrate, pro Pyrene glycol dipropionate, propylene glycol acetate dibutyrate, dipropylene glycol acetate propionate, dipropylene glycol acetate butyrate, dipropylene glycol propionate butyrate, dipropylene glycol dipropionate, dipropylene glycol acetate dibutyrate, etc. Glycol diacetates; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol; ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol monopropyl ether, diethylene glycol monoethyl Ether, diechi Glycol monobutyl ether, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tripropylene glycol Glycol ethers such as monomethyl ether; lactate esters such as methyl lactate, ethyl lactate, propyl lactate and butyl lactate are preferred.
The amount of the solvent contained in the solvent ink is preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and more preferably 80% by mass or more and 95% by mass with respect to the total amount of the ink. More preferably, it is% or less.
The solvent ink according to the present invention preferably does not contain water. By not containing water, the dispersion stability of the pigment can be improved, hydrolysis of the solvent can be suppressed, and corrosion of the head can be suppressed. In the solvent ink, the water content is more preferably 0.5% by mass or less, which is a normal moisture absorption amount.

<Resin>
The type of resin contained in the ink is not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene type Examples thereof include resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, and acrylic silicone resins.
Resin particles made of these resins may be used. An ink can be obtained by mixing resin particles with a material such as a colorant or an organic solvent in a resin emulsion state in which water is dispersed as a dispersion medium. As said resin particle, what was synthesize | combined suitably may be used and a commercial item may be used. Moreover, these may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles.

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, a rust preventive 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 side chain of the Si portion 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.

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

<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.

As a method for dispersing the ink of the present invention, a dispersion device using a media such as a ball mill, a sand mill, or a bead mill, or a medialess dispersion device may be used. In order to maintain the hollow structure of the inorganic hollow particles during dispersion, the media It is preferable to use a loess dispersion apparatus.
The medialess device can disperse the inorganic hollow particles while maintaining the hollow structure by avoiding media collision with the particles. Moreover, since no media-derived contamination is generated, generation of fine powder and coarse powder in the system can be suppressed. Furthermore, since the uniformity of the particle size distribution can be improved, good ink discharge properties can be obtained. Examples of the medialess disperser include a disperser that uses high-speed shearing force such as a collision dispersive type and an ultrasonic dispersive type, a disperser that uses high-speed stirring, and an ultrasonic disperser. Examples of the dispersing device that uses high-speed shearing force include device name: Nanovaita series laboratory machine C-ES008 (manufactured by Yoshida Kikai Kogyo Co., Ltd.). Examples of the ultrasonic dispersing apparatus include apparatus name: ultrasonic homogenizer US-150E (manufactured by Nippon Seiki Seisakusho Co., Ltd.).
The temperature of the dispersion during dispersion is preferably 5 ° C. or higher and 60 ° C. or lower, and more preferably 5 ° C. or higher and 50 ° C. or lower.
The dispersion medium in the dispersion apparatus using the medium needs to have mild conditions by appropriately selecting the media specific gravity and the media diameter so that the hollow structure of the inorganic hollow particles can be maintained.

<Ink physical properties>
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 is not particularly limited, and plain paper, glossy paper, special paper, cloth, and the like can be used. Good image formation is possible even with a non-permeable substrate.
The non-permeable base material is a base material having a surface with low water permeability and absorbability, and includes materials that do not open to the outside even if there are many cavities inside, more quantitatively. In the Bristow method, the water absorption amount from the start of contact to 30 msec ^1/2 is 10 mL / m ² or less.
As said non-permeable base material, plastic films, such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, a polypropylene, polyethylene, a polycarbonate film, can be used conveniently, for example.
The recording medium is not limited to those used as general recording media, and wallpaper, flooring, building materials such as tiles, cloth for clothing such as T-shirts, textiles, leather, and the like can be used as appropriate. Moreover, ceramics, glass, metal, etc. can also be used by adjusting the structure of the path | route which conveys a recording medium.

  For example, in the case of a polyethylene terephthalate (PET) film, a film having a thickness of 100 μm and a total light transmittance of 80% or more is exemplified.

<Ink cartridge>
The ink cartridge 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. For example, at least an ink bag formed of an aluminum laminate film, a resin film, or the like Preferred examples include those possessed.

Next, the ink cartridge will be described with reference to FIGS.
Here, FIG. 3 is a schematic view showing the ink cartridge, and FIG. 4 is a schematic view showing a modification of the ink cartridge of FIG.
As shown in FIG. 3, in the ink cartridge 201, the ink bag 241 is filled with the ink jet ink of the present invention from the ink inlet 242 and exhausted, and then the ink inlet 242 is closed by fusion. In use, a needle of an ink jet recording apparatus is pierced into an ink discharge port 243 made of a rubber member and supplied to the ink jet recording apparatus.
The ink bag 241 is formed of a packaging member such as an aluminum laminate film having low air permeability. As shown in FIG. 4, the ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably mounted on various ink jet recording apparatuses.
The ink cartridge 201 contains the ink of the present invention and can be used by being detachably attached to various ink jet recording apparatuses, and is particularly preferably used by being detachably attached to an ink jet recording apparatus described later.

<Recording apparatus and recording method>
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. In the following, the case where black (K), cyan (C), magenta (M), and yellow (Y) are used will be described. However, instead of or in addition to these, the ink of the present invention is used. good.
FIG. 1 is a perspective view of the apparatus. FIG. 2 is an explanatory 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 temperature of the drying step after recording the ink of the present invention on the recording medium by the ink jet method is preferably 50 ° C. or higher and 200 ° C. or lower. According to this temperature range, the influence of heat on the recording medium hardly occurs.
As described above, the ink of the present invention can be concealed by utilizing the scattering of the shell of the inorganic hollow particles and the internal pores in addition to the scattering of the particle surface. Therefore, if components such as a water-soluble organic solvent remain in the inorganic hollow particles after the coating film is dried, the concealability of the coating film is reduced. However, the ink of the present invention is formed by the inorganic particles. Compared to the hollow resin particles, it has higher solvent resistance even during high-temperature drying, so that it can be dried at high speed in a high-temperature environment.

In addition, the ink of the present invention has a lightness of 50 mm × 50 mm solid image formed on a polyethylene terephthalate (PET) film in a 50 ° C. constant temperature bath for 1 hour in a L * 50 ° C., 100 ° C. constant temperature bath for 1 hour. When the lightness when dried is L * 100 ° C., the absolute value of the lightness difference ΔL * represented by the following formula (1) can be 10 or less. That is, the ink of the present invention is excellent in the stability of an image (for example, whiteness).
ΔL * = (L * 100 ° C.) − (L * 50 ° C.) (1)

The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be applied to printed materials, paints, coating materials, foundations and the like. 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.

  Further, the terms “image formation”, “recording”, “printing”, “printing”, etc. in the terms of the present invention are all synonymous.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these examples.

<< Preparation of dispersion >>
(1) <Preparation example of inorganic hollow particles>
As the method for producing the inorganic hollow particles used in the present invention, those produced by a known technique as described above can be used. The production conditions of the inorganic hollow particles are shown in Table 1, and the production example 3 is described below as an example.
In a beaker, 18.15 parts by mass of calcium carbonate (manufactured by Shiraishi Kogyo Co., Ltd., product name “Hakuenka DD”, particle shape: cubic, surface treatment agent: rosin acid, primary particle diameter: 50 nm) 181.54 parts by mass (dimethylene) Glycol dimethyl ether (manufactured by Kishida Chemical Co., Ltd.) was sufficiently dispersed using a homogenizer (manufactured by Hitachi Koki, HG30, C20 cutter, 8000 rpm, 30 minutes). Thereafter, while sufficiently stirring to maintain the dispersed state of calcium carbonate, 14.52 parts by mass of tetraethoxysilane (TEOS, manufactured by Shin-Etsu Chemical Co., Ltd., product name “KBE-04”), 14.61 mass of 28% aqueous ammonia Parts (NH ₄ OH, manufactured by Wako Pure Chemical Industries) and 71.17 parts by mass of water are reacted at 25 ° C. for 4 hours, and a silica shell is formed on the surface of calcium carbonate using a sol-gel reaction. Silica coated particles were obtained.
Next, the obtained silica-coated particles were washed and dispersed in water. Further, acetic acid diluted 10 times was added to dissolve the calcium carbonate of the core particles. The pH after addition of acetic acid was 4.0. Then, water was washed using an ultrafiltration membrane for desalting and concentrated to obtain [18 mass% aqueous layer of inorganic hollow particles 3]. In any of the washing steps, since the silica-coated particles or the inorganic hollow particles may be aggregated when dried, liquid-liquid replacement was performed.

Similarly, under the conditions of each production example shown in Table 1, [18 mass% aqueous layer of inorganic hollow particles 1], [18 mass% aqueous layer of inorganic hollow particles 2] and [18 mass% of inorganic hollow particles 4] Aqueous layer] to [18 mass% aqueous layer of inorganic hollow particles 15] were obtained. In Production Example 14, a commercially available product was used, and a commercially available product “Sirinax” (manufactured by Nippon Steel Mining Co., Ltd., outer diameter 100 nm, inner diameter 80 nm, water dispersion type) was used as the inorganic hollow particles.
The details of the calcium carbonate used in Table 1 are as follows.
Viscal: (manufactured by New Lime, particle shape: cubic, surface treatment agent: none, primary particle size: 80 nm)
Brilliant-1500: (Shiraishi Kogyo, particle shape: cubic, surface treatment agent: none, primary particle size: 150 nm)
Homocal-D: (Shiraishi Kogyo, particle shape: cubic, surface treatment agent: rosin acid, primary particle size: 80 nm)
Homocal-DM: (Shiraishi Kogyo, particle shape: cubic, surface treatment agent: rosin acid, primary particle size: 80 nm)

(2) <Preparation example of inorganic hollow particle aqueous dispersion, inorganic hollow particle dispersions 1 to 15>
In 100 parts by mass of [18 mass% aqueous layer of inorganic hollow particles 3] obtained in (1), an amine group-containing acrylic block copolymer (dispersant, manufactured by BYK Japan, product name “BYKJET-9151”, acid Value: 8 mg KOH / g, amine value: 18 mg KOH / g, active ingredient 100% by mass) After adding 6 parts by mass and 14 parts by mass of water and stirring well, a medialess dispersion device (Yoshida Kikai Kogyo, NVC-ES008, 150 μm collision) Dispersion was performed using a mold nozzle, discharge pressure of 50 MPa, number of passes, 10 times. The obtained dispersion was filtered through a 5 μm membrane filter (cellulose acetate membrane) to prepare [Inorganic hollow particle dispersion 3] (particle concentration: 15 mass%).
Similarly, [18 mass% aqueous layer of inorganic hollow particles 1], [18 mass% aqueous layer of inorganic hollow particles 2], [18 mass% aqueous layer of inorganic hollow particles 4] to [18 of inorganic hollow particles 13]. [Inorganic hollow particle dispersion 1], [Inorganic hollow particle dispersion 2], [Inorganic hollow particle dispersion 4]-[Mass% aqueous layer] and [18% by mass aqueous layer of inorganic hollow particles 15] Inorganic hollow particle dispersion 13] and [Inorganic hollow particle dispersion 15] were prepared.
In addition, [Inorganic hollow particle dispersion 14] was prepared by preparing a commercially available product “Sirinax” as an inorganic hollow particle to a solid content concentration of 15% by mass.

(3) <Preparation of inorganic hollow particle solvent dispersion, inorganic hollow particle dispersion 16>
The solvent of [18 mass% aqueous layer of inorganic hollow particles 6] obtained in (1) was substituted with γ-butyrolactone. Furthermore, 50% by mass synergist (product name “Solsperse 12000”, manufactured by Louvre Resol, Inc.) is added to the inorganic hollow particles 6, and a homogenizer (manufactured by Hitachi Koki, HG30, C20 cutter, 8000 rpm, 60 minutes) is cooled with water. Dispersion. The solvent-based dispersion liquid of the obtained inorganic hollow particles 6 was filtered through a 5 μm membrane filter (PTFE membrane) to obtain [Inorganic hollow particle dispersion liquid 16] (particle concentration: 15.0 mass%).

(4) <Preparation of hollow resin particle dispersion>
As a polymerizable monomer, 25 parts by mass of ethylene glycol dimethacrylate (manufactured by NOF, “Blenmer PDE-50R”, number of polyoxyethylene units = 1), 50 parts by mass of trimethylolpropane trimethacrylate (manufactured by Sartomer, “SR351S”) , And 25 parts by mass of acrylonitrile, 95 parts by mass of toluene and 5 parts by mass of hexadecane as a non-polymerizable compound, and 1 part by mass of azobisisobutyronitrile as a polymerization initiator, and the total amount of the mixed solution stirred. A water-soluble emulsifier is added to 1600 parts by weight of ion-exchanged water containing 2% by weight of sodium dodecylbenzenesulfonate and 1% by weight of cetyl alcohol as a dispersion aid, and is forcibly emulsified with an ultrasonic homogenizer for 60 minutes. A dispersion in which droplets were dispersed was prepared.
Next, using a 20 L polymerization vessel equipped with a stirrer, a jacket, a reflux condenser and a thermometer, the inside of the polymerization vessel was depressurized, and after deoxidizing the vessel, the pressure was returned to atmospheric pressure with nitrogen gas. The inside of the polymerization vessel was set to a nitrogen atmosphere. The entire amount of the obtained dispersion was charged all at once into this polymerization vessel, and the polymerization vessel was heated to 60 ° C. to initiate polymerization. After polymerization for 4 hours, the polymerization vessel was cooled to room temperature to obtain a non-polymerizable compound-encapsulated microcapsule slurry. The obtained slurry was dried using a spray dryer to produce hollow fine particles.
When the obtained hollow fine particles were observed using a transmission electron microscope (manufactured by JEOL Ltd., “JEM-1200EXII”), the shape was almost spherical and the average particle size was 0.12 μm. Further, the obtained hollow fine particles had a structure having a single pore inside, and the shell portion ratio was 50% by volume.
5 parts by mass of an amine group-containing acrylic block copolymer (dispersant, manufactured by Big Chemie Japan, product name “BYKJET-9151”, acid value: 8 mgKOH / g, amine value: 18 mgKOH / g, active ingredient 100% by mass) The resultant was dissolved in 80 parts by mass, 15 parts by mass of the obtained hollow fine particles were added and sufficiently stirred, 80 parts by mass of zirconia balls having a diameter of 2 mm were added, and dispersion was performed for 2 days in a ball mill under the following conditions. The obtained dispersion was filtered through a 5 μm membrane filter (PTFE membrane) to prepare [hollow resin particle dispersion] (concentration: 15% by mass).

-Ball mill conditions-
Media: YTZ ball diameter 5mm
(Zirconia ball, manufactured by Nikkato Corporation)
YTZ ball diameter 1mm
(Zirconia ball, manufactured by Nikkato Corporation)
Mill: MIX-ROTAR VMR-5 (manufactured by ASONE Corporation)
Rotation speed: Mayonnaise bottle rotation speed 75rpm

(5) <Preparation of titanium oxide dispersion>
18.0 parts by mass of acrylic copolymer (dispersant, manufactured by Big Chemie Japan, product name “DISPERBYK-2008”, active ingredient 100% by mass, amine value: 66 mgKOH / g) in 67.0 parts by mass of high-purity water in a beaker 15.0 parts by mass of titanium dioxide (manufactured by Teika, product name “JR-600A”, primary particle size 250 nm, surface treatment: Al) is added and homogenizer (Hitachi Koki, HG30, C20 cutter, 8000 rpm, 60 minutes). The obtained titanium dioxide pigment dispersion was filtered through a 5 μm membrane filter (cellulose acetate film) to obtain [titanium oxide dispersion] (particle concentration: 15.0% by mass).

<< Preparation of ink >>
[Example 1]
-Inorganic hollow particle dispersion 1 (15 mass%) 53.3 mass parts-1,3-propanediol 12 mass parts-1,5-pentanediol 10 mass parts-3-methoxy-3-methyl-1-butanol 8 4 parts by mass, diethylene glycol monoethyl ether 4 parts by mass, polyurethane resin emulsion (35% by mass) 8 parts by mass, surfactant 0.1 part by mass, antifoaming agent 0.5 part by mass, antiseptic / antifungal agent 0.05 part by mass -PH adjuster 0.5 mass part * high purity water 3.55 mass part The ink of the said composition was prepared, and it filtered with a 5 micrometer membrane filter (cellulose acetate film | membrane), and obtained [Ink 1].

[Example 2] to [Example 15]
As shown in Tables 2 and 3, it was prepared in the same manner as [Ink 1] except that the inorganic hollow particle dispersion and the material composition ratio were changed, and [Ink 2] to [Ink 15] were obtained.

[Comparative Example 1] to [Comparative Example 4]
As shown in Table 4, it was prepared in the same manner as [Ink 1] except that the inorganic hollow particle dispersion and the material composition ratio were changed, and [Ink 16] to [Ink 19] were obtained.

[Comparative Example 5] and [Comparative Example 6]
As shown in Table 4, except that the inorganic hollow particle dispersion was changed to the hollow resin particle dispersion described above, and the material composition ratio was changed, it was prepared in the same manner as [Ink 1], and [Ink 20] and [Ink 20] Ink 21] was obtained.

[Comparative Example 7]
As shown in Table 4, it was prepared in the same manner as [Ink 1] except that the inorganic hollow particle dispersion was changed to the hollow resin particles described above and the material composition ratio was changed, and [Ink 22] was obtained.

[Comparative Example 8]
As shown in Table 4, except that the inorganic hollow particle dispersion was changed to the titanium oxide dispersion described above, and the material composition ratio was changed, it was prepared in the same manner as [Ink 1] to obtain [Ink 23]. .

  The 50% cumulative volume particle diameter (D50), number primary average particle diameter, inner diameter, and shell thickness of the inorganic hollow particles were determined. These can be determined using a transmission electron microscope (manufactured by JEOL, "JEM-2100F") as described above. The measurement results are shown in Tables 2 to 4.

In Tables 2 to 4, the materials used are as follows.
<Water-based ink>
1,3-propanediol (boiling point 188 ° C.)
1,2-butanediol (boiling point 195 ° C.)
1,5-pentanediol (boiling point 242 ° C.)
1,6-hexanediol (boiling point 223 ° C.)
3-methoxy-3-methyl-1-butanol (boiling point 174 ° C.)
2-ethyl-1,3-hexanediol (boiling point 244 ° C.)
3-methyl-1,3-butanediol (boiling point 204 ° C.)
Diethylene glycol monoethyl ether (boiling point 194 ° C)
Diethylene glycol monobutyl ether (boiling point 220 ° C)
Amide compound (R = CH ₃ ) having the following structure (produced by Idemitsu Kosan Co., Ltd., Ecamide M100, boiling point 216 ° C.)

Glycerin (boiling point 290 ° C)
Polyurethane resin emulsion: Mitsui Takeda Chemical Co., Ltd., W-5661, solid content 35% by mass
Surfactant A: Polyoxyethylene alkylene derivative (Nippon Yushi Co., Ltd., Dispanol TOC)
Surfactant B: Polyoxyethylene styrene phenyl ether (Daiichi Kogyo Seiyaku, Neugen EA-177)
Surfactant C: Fluorosurfactant (Polyfox manufactured by OMNOVA)
Antifoaming agent: Envirogem AD01
Antiseptic and antifungal agent: Proxel LV
pH adjuster: 1N-NaOH

<Solvent ink>
Triethylene glycol monoethyl ether (boiling point 248 ° C)
Propylene glycol monopropyl ether (boiling point 149 ° C)
Diethylene glycol diethyl ether (bp 188 ° C)
γ-butyrolactone (boiling point 204 ° C.)
2-octanone (boiling point 173 ° C)
Polyester resin emulsion: Pesresin S-100EA made by Takamatsu Yushi
Epoxidized soybean oil dispersant: Solsperse 5000 (made by Louvre Resol)

  The following evaluation was performed about each obtained ink.

<< Quantitative evaluation of calcium ions in ink >>
Calcium ions in the inks prepared in Examples 1 to 15 and Comparative Examples 1 to 4 were quantified using an ICP emission spectroscopic analyzer (ICPE-9000, manufactured by Shimadzu Corporation), and evaluated according to the following evaluation criteria. .
[Evaluation criteria]
AA: The amount of calcium ions in the ink is less than 0.5 ppm A: The amount of calcium ions in the ink is 0.5 ppm or more and 30 ppm or less B: The amount of calcium ions in the ink exceeds 30 ppm and is 50 ppm or less C : The amount of calcium ions in the ink exceeds 50 ppm and 250 ppm or less. D: The amount of calcium ions in the ink exceeds 250 ppm.

<< Ink sedimentation evaluation >>
The sedimentation properties of the ink particles prepared in Examples 1 to 15 and Comparative Examples 1 to 8 were evaluated using Turbiscan MA2000 (manufactured by Eihiro Seiki).
As a method, ultrasonic evaluation treatment (100 w, 20 minutes) was performed while cooling the evaluation ink with water, and after uniformly dispersing, 5.0 mL of the evaluation ink was put into a dedicated glass cell using a pipette. Measurement was performed 30 minutes after the liquid level of the evaluation ink in the cell was stabilized, and this time was set as the start of sedimentation evaluation. Then, it left still at 23 degreeC, it measured until 150 hours later, and sedimentation was evaluated by the deviation display on the basis of the sedimentation evaluation start. For the evaluation of sedimentation, the change in the backscattered light due to the generation of the supernatant was performed by peak integration (relative value mode), and the rank was evaluated according to the following criteria.
[Evaluation criteria]
A: Relative change less than 5% after 150 hours from the start of evaluation B: Relative change after 150 hours from the start of evaluation is 5% or more and less than 10% C: Relative change after 150 hours from the start of evaluation is 10% or more

<< Ink storage stability >>
The inks prepared in Examples 1 to 15 and Comparative Examples 1 to 8 were filled in ink cartridges and stored at 65 ° C. for 3 weeks. A cone plate type rotational viscometer (device name: VISCOMETER TV-22, Toki Sangyo Co., Ltd.) The viscosity before and after storage was measured under the conditions of a constant temperature circulating water temperature of 25 ° C., a rotation speed of 50 rpm, and a shear rate of 191.4 sec ⁻¹ , and evaluated according to the following criteria.
〔Evaluation criteria〕
A: The rate of change in viscosity before and after storage is within ± 5%.
B: Viscosity change rate before and after storage exceeds ± 5% and is within ± 10%.
C: Viscosity change rate before and after storage exceeds ± 10% and is within ± 15%.
D: Viscosity change rate before and after storage exceeds ± 15%.

<Printing conditions>
Remove the exterior of the inkjet printer (Ricoh's IPSiOGXe5500), attach the rear multi-manual feeder, clean it by passing pure water through the ink supply path including the print head, and pass it thoroughly until the cleaning liquid stops coloring. Then, the cleaning liquid was completely removed from the apparatus to obtain an evaluation printing apparatus.
Further, the prepared ink was stirred for 30 minutes under a reduced pressure condition of 5 to 10 Pa, thereby degassing the gas in the evaluation ink and filling the ink cartridge to obtain an evaluation ink cartridge. A filling operation was performed, and it was confirmed that all nozzles were filled with evaluation ink and no abnormal image appeared. After selecting the glossy paper clean mode with the driver attached to the printer, the color matching off was set to the print mode by the user setting. In this mode, the ejection amount was adjusted by changing the driving voltage of the head so that the amount of ink adhering to the medium of the solid image was 20 g / m ² .

<< Concealment evaluation >>
≪Brightness evaluation of printed image≫
Transparent PET film (manufactured by Toyobo Co., Ltd.) filled with ink prepared in Examples 1 to 15 and Comparative Examples 1 to 8 into an ink jet printer (Ricoh: IPSiOGXe5500) and fixed with double-sided tape on My Paper (Ricoh PPC plain paper) A solid image of 50 cm × 50 cm created by Microsoft Word 2003 was printed on the ester film E5100), and then dried in a thermostatic bath at 50 ° C. for 1 hour.
With the commercially available black paper laid under the printed PET film, the printed portion was measured for lightness (L *) using a spectrocolorimetric densitometer X-Rite 939, and evaluated according to the following criteria.
[Evaluation criteria]
A: L * value is 70 or more B: L * value is 60 or more, less than 70 C: L * value is less than 60 For reference, measurement was performed with an unprinted PET film laid on black paper. The L * value was 23.

≪Whiteness stability of printed image≫
Transparent PET film (manufactured by Toyobo Co., Ltd.) filled with ink prepared in Examples 1 to 15 and Comparative Examples 1 to 8 into an ink jet printer (Ricoh: IPSiOGXe5500) and fixed with double-sided tape on My Paper (Ricoh PPC plain paper) A solid image of 50 cm × 50 cm prepared by Microsoft Word 2003 was printed on the ester film E5100).
After printing, the brightness of a recording medium placed in a 50 ° C. constant temperature bath and dried for 1 hour and that which was put in a 100 ° C. constant temperature bath for 1 hour were measured, and the brightness difference ΔL * = (L * 100 ° C. )-(L * 50 ° C.) was calculated and evaluated.
The brightness was measured with a commercially available black paper placed under the printed PET film, and the printed portion was measured using a spectrocolorimetric densitometer X-Rite 939, and evaluated according to the following criteria.
[Evaluation criteria]
A: | ΔL * | value is less than 5 B: | ΔL * | value is 5 or more and less than 10 C: | ΔL * | value is 10 or more

<< Brightness evaluation of printed image (temperature dependence) >>
Transparent PET film (Toyobo Ester Film E5100) filled with the ink prepared in Example 9 and Comparative Example 6 into an ink jet printer (Ricoh: IPSiOGXe5500) and fixed with double-sided tape on My Paper (Ricoh PPC plain paper) On the other hand, a solid image of 50 cm × 50 cm created by Microsoft Word 2003 was printed.
After printing, the lightness L * of the recording medium placed in a 50 ° C. constant temperature bath for 1 hour, the one stored in a 100 ° C. constant temperature bath for 1 hour, and the one stored in a 150 ° C. constant temperature bath for 1 hour, respectively. Measured and evaluated according to the following criteria.
[Evaluation criteria]
A: L * value is 70 or more B: L * value is 60 or more and less than 70 C: L * value is less than 60 The results are shown in Table 8.

<< Solvent Resistance Evaluation >>
Inks prepared in Examples 1 to 9, Examples 11 to 15, Comparative Examples 1 to 6 and Comparative Example 8 were filled in an ink jet printer (Ricoh: IPSiOGXe5500), and on My Paper (Ricoh PPC plain paper). A 50 cm × 50 cm solid image created by Microsoft Word 2003 was printed on a transparent PET film (Toyobo Ester Film E5100) fixed with a double-sided tape, and then dried in a constant temperature bath at 100 ° C. for 60 minutes.
A cotton swab was impregnated with an aqueous solution containing 49% ethanol and 1% methyl ethyl ketone, the solid portion of the image was rubbed 20 times, and the solid film was peeled off and evaluated according to the following criteria.
〔Evaluation criteria〕
A: Peeling is not seen at all on the solid part, and dirt is not seen on the cotton swab.
B: Peeling is not found on the solid part, but the dirt is slightly adhered to the cotton swab.
C: Ink melted out in the solid portion.
D: The solid part of the ink is peeled off and a part or more of the PET film is exposed.

<< Discharge stability >>
The inks prepared in Examples 1 to 15 and Comparative Examples 1 to 8 were filled in an ink jet printer having a cover means (Ricoh: IPSiO GXe5500), and the head was covered with a temperature of 10 ° C. and a humidity of 15% RH for one week. After being allowed to stand, a nozzle check pattern was printed, and the presence or absence of ejection failure or ejection disturbance was evaluated by visual observation based on the following criteria.
〔Evaluation criteria〕
A: There is no non-ejection and ejection disturbance.
B: Some injection disturbance is recognized.
C: There is a nozzle where non-ejection is recognized.
D: Non-ejection is recognized in a plurality of nozzles.

  The evaluation results of the above water-based inks are summarized in Tables 5 and 6, and the evaluation results of the solvent ink are summarized in Table 7.

As in Examples 1 to 15, the inorganic hollow particles were contained, the 50% cumulative volume particle size of the inorganic hollow particles in the ink was 50 nm to 350 nm, and the calcium ion content in the ink was 0.5 ppm to 250 ppm. In the following cases, good results were obtained for sedimentation evaluation, hiding evaluation, solvent resistance and the like.
On the other hand, as in Comparative Example 1 and Comparative Example 4, when the 50% cumulative volume particle size of the inorganic hollow particles exceeded 350 nm, the hollow particles were easily settled. This is probably because even if the primary particles of the inorganic hollow particles are small, they are aggregated in the ink, and the apparent specific gravity is increased by the binding solvent between the particles. Further, as in Comparative Example 2, when the amount of calcium ions in the ink exceeded 250 ppm, a decrease in storage stability was confirmed. The commercially available product of Comparative Example 3 was a result of severe particle aggregation and easy sedimentation.
In addition, when hollow resin particles were used as in Comparative Example 5 and Comparative Example 6, the result showed that the whiteness stability of the hiding property evaluation was extremely low. This is presumably because when the ink component evaporates by drying, the evaporation rate of the solvent having a high boiling point component is slow, so that the highly soluble component is concentrated and the resin skeleton forming the hollow is dissolved. The same applies to Comparative Example 7.
Further, as in Comparative Example 8, when titanium oxide was used, the particle specific gravity was large, so that the result of being easily settled was obtained. In addition, when the solvent of a high boiling point component is included like Example 9 and Comparative Example 6, it is estimated that the solvent component tends to remain in the hollow particles, and the result that the whiteness is slightly low is obtained. However, in Example 9, it was confirmed that high whiteness can be obtained by increasing the drying conditions.
From the above results, the 50% cumulative volume particle size of the inorganic hollow particles in the ink is 50 nm or more and 350 nm or less, and the calcium ion content in the ink is 0.5 ppm or more and 250 ppm or less, which is desired in the present invention. The effect of can be produced.

201 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge case 400 Image forming apparatus 401 Exterior of image forming apparatus 401c Cover of apparatus main body 404 Cartridge holder 410 Main tank 410k, 410c, 410m, 410y Black (K), Main tank for each color of cyan (C), magenta (M), and yellow (Y) 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Discharge head 436 Supply tube

JP 2014-122310 A JP 2007-2111176 A JP 2012-7089 A

Claims (11)

  An ink containing a volatile solvent, inorganic hollow particles, and calcium ions, wherein the amount of calcium ions in the ink is 0.5 ppm or more and 250 ppm or less, and a 50% cumulative volume particle size of the inorganic hollow particles is 50 nm or more. An ink having a thickness of 350 nm or less.   The ink according to claim 1, wherein the calcium ion amount is 0.5 ppm or more and 50 ppm or less.   The ink according to claim 2, wherein the calcium ion amount is 0.5 ppm or more and 30 ppm or less.   The ink according to claim 1, wherein the volatile solvent is a non-polymerizable solvent and has a boiling point of 260 ° C. or lower.   The ink according to any one of claims 1 to 4, wherein the volatile solvent is water or a water-soluble organic solvent.   The ink according to any one of claims 1 to 4, wherein the volatile solvent is an organic solvent.   The ink according to any one of claims 1 to 6, wherein a shell thickness of the inorganic hollow particles is 4 nm or more and 20 nm or less. The brightness when a solid image of 50 mm x 50 mm formed on a polyethylene terephthalate (PET) film is dried in a constant temperature bath at 50 ° C for 1 hour is L * 50 ° C, and the brightness when dried in a constant temperature bath at 100 ° C is L * The ink according to any one of claims 1 to 7, wherein the absolute value of the lightness difference ΔL * represented by the following formula (1) is 10 or less when the temperature is 100 ° C.
ΔL * = (L * 100 ° C.) − (L * 50 ° C.) (1)   9. An ink jet recording method in which the ink according to any one of claims 1 to 8 is recorded on a recording medium by an ink jet method and includes a drying step after recording. The temperature of the drying step is 50 ° C. or higher and 200 ° C. or lower. An ink jet recording method, comprising:   An ink cartridge comprising the ink according to claim 1 contained in a container. An image recording apparatus comprising an ink cartridge containing ink and a recording head for ejecting ink, wherein the ink is the ink according to claim 1. .

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