JP2018127521A - Ink, ink container, ink set, inkjet recording device, inkjet recording method, and recorded matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink that exhibits good adhesion to a polyolefin based resin substrate, is excellent in storage stability and discharge stability, and realizes high image quality.SOLUTION: The ink contains a polyester resin particulate, a silicone based surfactant, and an organic solvent represented by the general formula (1) in the figure, where R represents a hydrogen atom or methyl group.SELECTED DRAWING: Figure 1

Description

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

Inkjet printers have advantages such as low noise, low running cost, and easy color printing, and thus are widely used as digital signal output devices in general households.
In recent years, not only for home use but also for non-absorbent recording media such as plastic films, it has become commercially required to obtain image quality equivalent to that of conventional analog printing by the ink jet recording method. ing. For example, in the food packaging field called so-called soft packaging, the demand for variable printing is increasing in addition to the rapid advancement of small lots and various types of print jobs. An ink jet recording system corresponding to a film for flexible packaging is desired.

Examples of such soft packaging inks include oil-based inks, ultraviolet curable inks, and water-based inks. From the viewpoint of low VOC (Volatile Organic Compounds) and safety, water-based inks Development is thriving.
For example, Patent Document 1 discloses a polyester resin particle having a specific monomer composition as a water-based ink for ink-jet recording having excellent adhesion to a resin recording medium such as PVC (polyvinyl chloride), abrasion resistance, and alcohol resistance. Ink containing is proposed.
Patent Document 2 discloses a water-based ink composition using a polypropylene-based resin emulsion as an aqueous ink-jet ink composition that can be printed directly on a polyolefin-based resin substrate and can realize excellent printed matter resistance and adhesion. Things have been proposed.

However, in the ink described in Patent Document 1, since the polarity of the film surface is low, it may cause poor adhesion to a polyolefin-based film known as a difficult-to-adhere substrate, resulting in insufficient laminate strength.
Moreover, when using the resin emulsion of patent document 2, there existed a subject that storage stability was bad and ink discharge became easy to become unstable. In other words, unlike an absorbent recording medium such as paper in which high boiling point solvents permeate, a non-absorbent recording medium is required to have a quicker drying property in order to achieve high productivity. If the solvent ratio of the low boiling point is increased instead of decreasing the solvent ratio of the high boiling point for improvement, there is a problem that the nozzle is easily clogged in a short time.

  Accordingly, an object of the present invention is to provide an ink that has good adhesion to a polyolefin resin substrate, is excellent in storage stability and ejection stability, and provides high image quality.

The above problem is solved by the following configuration 1).
1) An ink comprising polyester resin particles, a silicone-based surfactant, and an organic solvent represented by the following general formula (1).

(In general formula (1), R represents a hydrogen atom or a methyl group.)

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness to a polyolefin-type resin base material is favorable, it is excellent in storage stability and discharge stability, and the ink from which a high image quality is obtained can be provided.

FIG. 3 is a perspective view illustrating a recording apparatus. It is a perspective view of a main tank.

Hereinafter, embodiments of the present invention will be further described.
The ink of the present invention comprises polyester resin particles, a silicone-based surfactant, and an organic solvent represented by the general formula (1) described below.

<Ink>
Hereinafter, the organic solvent, water, color material, resin, additive, and the like used for the ink will be described.

(Polyester resin particles)
The polyester resin constituting the polyester resin particles is not particularly limited and can be appropriately selected from known ones. However, in order to obtain an ink excellent in adhesion to a recording medium, storage stability, and ejection stability, a polyester resin is used. The glass transition temperature (Tg) is preferably from 58 ° C to 93 ° C, more preferably from 60 ° C to 90 ° C, and particularly preferably from 65 ° C to 85 ° C.
The polyester resin is obtained using a diol component and a dicarboxylic acid, but a polyester resin having a branched structure using a tri- or higher valent acid or alcohol is also preferably used.

[Diol]
The diol is not particularly limited and can be appropriately selected depending on the purpose. For example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 3-methyl- Aliphatic diols such as 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol; diethylene glycol, triethylene glycol, dipropylene glycol, Diols having an oxyalkylene group such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol; alicyclic diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; alicyclic diols including ethylene oxide and propylene oxide Alkylene oxides such as butylene oxide; bisphenols such as bisphenol A, bisphenol F, and bisphenol S; alkylene oxides of bisphenols such as those obtained by adding alkylene oxide such as ethylene oxide, propylene oxide, and butylene oxide to bisphenols Adducts; and the like. Among these, it is preferable to contain an alkylene oxide adduct of bisphenol A in an amount of 50% by mass or more based on the total diol component in order to suppress film formation on the nozzle surface and prevent an increase in ink viscosity during long-term storage.

[Dicarboxylic acid]
It does not restrict | limit especially as dicarboxylic acid, According to the objective, it can select suitably, For example, aliphatic dicarboxylic acid, aromatic dicarboxylic acid, etc. are mentioned.
The aliphatic dicarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include succinic acid, adipic acid, sebacic acid, dodecanedioic acid, maleic acid, and fumaric acid.
The aromatic dicarboxylic acid is not particularly limited and may be appropriately selected depending on the purpose, but an aromatic dicarboxylic acid having 8 to 20 carbon atoms is preferable. The aromatic dicarboxylic acid having 8 to 20 carbon atoms is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. Among them, in order to improve the storage stability in the ink and suppress the increase in viscosity at the nozzle during decap, it is preferable to contain isophthalic acid and / or terephthalic acid in an amount of 50% by mass or more based on the total dicarboxylic acid component. .

[Trivalent or higher acid or alcohol]
As the component for forming a non-linear structure, that is, a branched structure, a conventionally known trivalent or higher acid or alcohol can be used.
Examples of trihydric or higher alcohols include trihydric or higher aliphatic alcohols, trihydric or higher polyphenols, and alkylene oxide adducts of trihydric or higher polyphenols. The trihydric or higher aliphatic alcohol is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol. The trihydric or higher polyphenols are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include trisphenol PA, phenol novolak, cresol novolak, and the like. Examples of the alkylene oxide adducts of trihydric or higher polyphenols include those obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to trihydric or higher polyphenols.

  Examples of the trivalent or higher acid include trivalent or higher aromatic carboxylic acid. Although it does not restrict | limit especially as said trivalent or more aromatic carboxylic acid, Although it can select suitably according to the objective, C9-C20 trivalent or more aromatic carboxylic acid is preferable. The trivalent or higher aromatic carboxylic acid having 9 to 20 carbon atoms is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include trimellitic acid and pyromellitic acid.

  Further, as the polycarboxylic acid, an acid anhydride or a lower alkyl ester of any of dicarboxylic acid, trivalent or higher carboxylic acid, and a mixture of dicarboxylic acid and trivalent or higher carboxylic acid can be used. The lower alkyl ester is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include methyl ester, ethyl ester, and isopropyl ester.

  The acid value of the polyester resin is preferably 5 mg to 50 mg KOH / g, and more preferably 10 mg to 40 mg KOH / g, in order to disperse the resin in an aqueous medium and obtain resin particles having excellent stability.

  As a weight average molecular weight of the said polyester resin, 5000-100000 are preferable from a viewpoint of the adhesiveness to a film, and 10000-50000 are more preferable. The weight average molecular weight can be measured by a known GPC method.

  Further, the dispersion of the polyester resin in the aqueous medium, that is, the resin particle formation is achieved by a method of neutralizing or quaternizing some or all of the hydrophilic groups of the polyester resin, and then adding water to disperse in water. it can. At that time, a water-soluble organic solvent may be used as a dispersion auxiliary solvent, and the solvent may be distilled off after water dispersion.

  Further, the volume average particle diameter of the polyester resin particles is preferably from 50 nm to 80 nm, more preferably from 63 nm to 72 nm, from the viewpoint of ejection stability. The volume average particle diameter can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

  In addition to the polyester resin particles, known resin particles may be used in combination with the ink of the present invention. Examples of the resin particles include urethane resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. .

(Silicone surfactant)
The silicone-based surfactant is not particularly limited and can be appropriately selected according to the purpose, but in order to improve ink wetting with respect to a polyolefin-based resin substrate such as a polypropylene-based film and realize excellent adhesion. Is preferably a compound represented by the following general formula (2).

(In General Formula (2), R represents a hydrogen atom or a methyl group, m ₁ and m ₂ each independently represents an integer of 0 to 6, and n represents an integer of 2 to 20.)

  Examples of the compound represented by the general formula (2) include BYK-345, 347, 348, 349 (manufactured by BYK), WET240, 270, 280 (manufactured by Evonik), SAG002, 013, 503A (Nisshin Chemical). Industrial)).

  In the ink of the present invention, in addition to the silicone surfactant, any of a fluorine surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.

Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. The polyoxyalkylene ether polymer compound is particularly preferred because of its low foamability. 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 the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene. Examples include sorbitan 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.

(Organic solvent)
The ink of the present invention contains an organic solvent represented by the following general formula (1).

(In general formula (1), R represents a hydrogen atom or a methyl group.)

In addition, the ink of this invention may contain organic solvents other than the organic solvent represented by the said General formula (1), and can use a well-known water-soluble organic solvent suitably. Examples thereof include ethers such as polyhydric alcohols, 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 thereof 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.

The content of the polyester resin particles with respect to the whole ink of the present invention is preferably 1 to 30% by mass, and more preferably 2 to 15% by mass. In addition, when using resin particles other than the said polyester resin particle, the content with respect to the whole ink is 0-3 mass%, for example.
The content of the silicone surfactant relative to the whole ink of the present invention is preferably 0.01 to 5% by mass, and more preferably 0.1 to 3% by mass. In addition, when using surfactant other than the said silicone type surfactant, the content with respect to the whole ink is 0-0.5 mass%, for example.
1-40 mass% is preferable and, as for content of the organic solvent represented by the said General formula (1) with respect to the whole ink of this invention, 2-20 mass% is more preferable. In addition, when using organic solvents other than the organic solvent represented by the said General formula (1), content with respect to the whole ink is 0-30 mass%, for example.

<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 or more and 90% by mass or less, and 20% by mass from the viewpoint of ink drying property and ejection reliability. % To 60% by 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 (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone 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 pigments 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 metal pigments such as titanium oxide, and organic pigments such as 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, etc.
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, and 35 are mentioned.

  The content of the color material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass from the viewpoints of improvement in image density, good fixability and ejection stability. It is as follows.

In order to obtain an ink by dispersing a pigment, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing, a dispersing agent is used. Method, etc.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of making it dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment (for example, carbon) Is mentioned.
As a method for coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is included in microcapsules and dispersible in water can be mentioned. This can be paraphrased as a resin-coated pigment. In this case, it is not necessary that all pigments blended in the ink are coated with a resin, and within a range where the effects of the present invention are not impaired, uncoated pigments and partially coated pigments are dispersed in the ink. It may be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular type dispersant or high-molecular type dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and naphthalenesulfonic acid Na formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
An ink can be obtained by mixing a material such as water or an organic solvent with a pigment. Further, it is also possible to produce an ink by mixing a pigment, other water, a dispersant, and the like into a pigment dispersion and mixing a material such as water or an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. For dispersion, a disperser is preferably used.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of maximum number because the pigment dispersion stability is good and the image quality such as ejection stability and image density is also high. 500 nm or less is preferable and 20 nm or more and 150 nm or less are more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good ejection stability and increasing the image density, 0.1% by mass. % To 50% by mass is preferable, and 0.1% to 30% by mass is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.

  The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of improving the image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number Is preferably 20 nm to 1000 nm, and more preferably 20 nm to 150 nm. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Additives>
If necessary, an antifoaming agent, an antiseptic / antifungal agent, a rustproofing agent, a pH adjusting agent, or the like may be added to the ink.

<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.

<Rust preventive>
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.

<Pretreatment liquid>
The pretreatment liquid contains a flocculant, an organic solvent, and water, and may contain a surfactant, an antifoaming agent, a pH adjuster, an antiseptic / antifungal agent, an antirust agent, and the like as necessary.
For organic solvents, surfactants, antifoaming agents, pH adjusters, antiseptic / antifungal agents, and rust preventive agents, the same materials as those used for ink can be used, and other materials used for known processing liquids can be used. .
The type of the flocculant is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, and polyvalent metal salts.

<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.

<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.

<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. 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 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. 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.

  When the pretreatment apparatus is used, for example, after applying a pretreatment liquid containing the flocculant to the recording medium, the ink of the present invention can be ejected onto the recording medium. This form is particularly effective in preventing image bleeding and density unevenness.

  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 demonstrate this invention further more concretely, this invention is not limited by these examples.

(Preparation Example 1 of Pigment Dispersion)
<Preparation of black pigment dispersion>
After pre-mixing the following prescription mixture, a black pigment dispersion (pigment concentration) was circulated and dispersed for 7 hours in a disk-type bead mill (manufactured by Shinmaru Enterprises Co., Ltd., KDL type, media: 0.3 mm diameter zirconia ball used). : 15% by mass).
Carbon black pigment (trade name: Monarch 800, manufactured by Cabot Corporation) 15 parts by mass Anionic surfactant (trade name: Pionein A-51-B, manufactured by Takemoto Yushi Co., Ltd.) 2 parts by mass Ion exchange water ... 83 parts by mass

[Production of polyester resin particle dispersion 1]
A four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, terephthalic acid, adipic acid, and trimellitic acid as an acid component in a molar ratio of 85/13/2, and bisphenol A propylene as an alcohol component An oxide 2 mol adduct was charged so that the molar ratio OH / COOH of hydroxyl group to carboxyl group was 1.15, and 300 ppm of titanium tetraisopropoxide was added. Next, the temperature was gradually raised at normal pressure, and after reaching 230 ° C., the reaction was allowed to proceed for 2 hours. After further reaction at 10 kPa for 1 hour, the pressure was returned to normal pressure and the polyester resin was recovered.
300 g of the polyester resin and 300 g of methyl ethyl ketone were mixed in a 2 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple. Dissolved at 40 ° C. Next, triethylamine was added so that the acid value was equal to the acid value of the polyester resin, and 1000 parts of ion-exchanged water was added and sufficiently stirred. Furthermore, the polyester resin particle dispersion 1 was obtained by distilling off methyl ethyl ketone.

[Production of polyester resin particle dispersion 2]
Polyester resin particle dispersion 2 was obtained in the same manner except that the molar ratio of terephthalic acid, adipic acid and trimellitic acid was changed to 90/8/2 in the production of polyester resin particle dispersion 1.

[Production of polyester resin particle dispersion 3]
Polyester resin particle dispersion 3 was obtained in the same manner except that the molar ratio of terephthalic acid, adipic acid and trimellitic acid was set to 94/4/2 in the production of polyester resin particle dispersion 1.

[Production of polyester resin particle dispersion 4]
In the production of the polyester resin particle dispersion 1, a polyester resin particle dispersion 4 was obtained in the same manner except that the molar ratio of terephthalic acid, adipic acid and trimellitic acid was 98/0/2.

[Production of polyester resin particle dispersion 5]
Polyester resin particle dispersion 5 was obtained in the same manner except that the molar ratio of isophthalic acid, adipic acid and trimellitic acid was set to 94/4/2 in the production of polyester resin particle dispersion 1.

[Production of polyurethane resin particle dispersion]
In a 500 mL flask, 159 parts of propylene glycol and 291 parts of dimethyl terephthalate were charged and melted uniformly at 120 ° C., and then 0.1 part of tetraisopropoxy titanium was added as a catalyst. Next, the temperature was raised to 220 ° C. over 3 to 4 hours with stirring and held for 5 hours, and then reacted while reducing the pressure at 15 kPa. When the number average molecular weight reached 1000, the pressure was returned to normal pressure. It was collected. The obtained polyester polyol had an acid value of 0.4 mgKOH / g and a hydroxyl value of 112 mgKOH / g.
Next, a nitrogen-substituted 2 L flask equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer was charged with 300 parts of the polyester polyol, 180 parts of isophorone diisocyanate, 20 parts of 2,2′-dimethylolpropionic acid, acetone. 200 parts were added and reacted at 65 ° C. for 5 hours. At this time, the concentration of the isocyanate group relative to the whole reaction solution was 3.5 wt%.
Then, after cooling to 40 ° C. and adding 15.4 parts of triethylamine, 1200 parts of ion-exchanged water was added and sufficiently stirred. Further, 12 parts of diethylenetriamine was added and reacted for 1 hour, and then acetone was distilled off to obtain a polyurethane resin particle dispersion.

[Production of styrene acrylic resin particle dispersion]
69.3 parts of methyl methacrylate, 12.2 parts of styrene, 11.1 parts of 2-ethylhexyl acrylate, 1.9 parts of methacrylic acid, 1.5 parts of Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.), ion A mixture comprising 51.6 parts of exchange water was emulsified using a homomixer to obtain a uniform milky white emulsion.
In a 250 mL flask equipped with a stirrer, thermometer, nitrogen gas introduction tube, and reflux tube, 89 parts of ion-exchanged water was charged, and the temperature was raised to 70 ° C. while introducing nitrogen. Next, 0.8 parts of a 10% Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.) aqueous solution and 2.6 parts of a 5% ammonium persulfate aqueous solution were added, and the previously prepared emulsion was added for 2.5 hours. It was dripped continuously over time. Moreover, 0.6 part of 5% ammonium persulfate aqueous solution was thrown in every 1 h until 3 hours passed since the dripping start. After completion of dropping, the mixture was aged at 70 ° C. for 2 hours and then cooled, and adjusted with 28% aqueous ammonia to adjust the pH to 7 to 8 to obtain a styrene acrylic resin particle dispersion.

  Table 1 shows the solid content, Tg, and volume average particle diameter of each resin particle dispersion.

(Preparation of ink)
Ingredients were mixed according to the formulation shown in Table 2 below and stirred for 1 hour, followed by pressure filtration with a 0.8 μ cellulose acetate membrane filter to obtain inks 1 to 13. Note that 3-methoxy-1-butanol is an organic solvent in which R is a hydrogen atom in the general formula (1), and 3-methoxy-3-methyl-1-butanol has a methyl group in the general formula (1). An organic solvent.

  For the inks 1 to 13, the following characteristics were evaluated. The results are shown in Table 3.

<Storage stability>
Add 5g of ink to Laboran Screw Tube No.3 (manufactured by ASONE), store it in a thermostatic chamber set at 70 ° C for 1 week, calculate the rate of change in viscosity from the viscosity of the ink before and after storage, and evaluate it according to the following criteria did.
Viscosity change rate = 100 × (viscosity after 2 weeks at 70 ° C.−initial viscosity) / initial viscosity [%]
○: Viscosity change rate is less than ± 10% △: Viscosity change rate is ± 10% or more and less than 30% ×: Viscosity change rate is ± 30% or more

<Printing method>
In order to create a solid image for evaluation, the IPSiO GXe5500 machine (manufactured by Ricoh Co., Ltd.) was modified so that a record corresponding to a recording speed of 30 m ² / hr with a printing width of 150 cm can be reproduced in A4 size, and a hot plate Was used, and an ink jet printer modified so that the heating conditions (heating temperature, heating time) after recording could be changed was used.
Filling the ink jet printer with ink, forming a solid image with an adhesion amount of 600 mg / A4, and drying it on a hot plate (NINOS ND-1, manufactured by ASONE Corporation) set at 80 ° C. for 3 minutes to obtain a solid image Got.

<Adhesion>
A pyrene film P2111 (manufactured by TOYOBO) having a thickness of 20 μm was used as a recording medium, and the surface was subjected to corona treatment, and a solid image was formed on the treated surface as described above. A cross-cut peel test using a cloth adhesive tape (123LW-50, manufactured by Nichiban Co., Ltd.) was performed on the solid image. The number of remaining cells in 100 test cells was counted, and the adhesion was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
○: Remaining mass number is 98 or more Δ: Remaining mass number is 90 or more and less than 98 ×: Remaining mass number is less than 90

<Discharge stability>
[Decap rating]
The ink was filled into the ink jet printer (device name: IPSiO GXe5500 remodeled machine, manufactured by Ricoh Co., Ltd.), and the ejection property after decap was evaluated. First, in an environment of 25 ° C. and 20% RH, head cleaning was executed by a printer maintenance command, a test chart was printed, and it was confirmed that all the channels of the nozzles were in a discharge state. Next, the test chart was printed again after being left for 10 minutes with the head cap removed. The number of non-ejection channels was counted from the test chart before and after being left, and judged according to the following criteria.
〔Evaluation criteria〕
○: The number of discharge channels is 5 or less Δ: The number of discharge channels is 5 or more and less than 30 ×: The number of discharge channels is 30 or more

  From the results in Table 3, the ink of the example containing the polyester resin particles, the silicone-based surfactant, and the organic solvent represented by the general formula (1) is compared with the ink of the comparative example that does not satisfy the condition. It has been found that the adhesiveness to the polyolefin resin substrate is good, and that the storage stability and the ejection stability are excellent. In addition, it was confirmed that the ink of the example had higher image quality than the ink of the comparative example.

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 For each color of black (K), cyan (C), magenta (M), yellow (Y) Main tank 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Discharge head 436 Supply tube

Japanese Unexamined Patent Publication No. 2016-113542 JP 2010-116459 A

Claims (10)

An ink comprising polyester resin particles, a silicone-based surfactant, and an organic solvent represented by the following general formula (1).

(In general formula (1), R represents a hydrogen atom or a methyl group.)   The ink according to claim 1, wherein the polyester resin particles have a glass transition temperature of 60 ° C. or higher and 90 ° C. or lower.   The ink according to claim 1 or 2, wherein the polyester resin particles have a volume average particle diameter of 50 nm or more and 80 nm or less. The ink according to claim 1, wherein the silicone-based surfactant contains a compound represented by the following general formula (2).

(In General Formula (2), R represents a hydrogen atom or a methyl group, m ₁ and m ₂ each independently represents an integer of 0 to 6, and n represents an integer of 2 to 20.)   An ink storage container comprising an ink storage unit storing the ink according to claim 1.   An ink set comprising a pretreatment liquid containing a flocculant and the ink according to claim 1.   An ink jet recording apparatus having an ejection unit that ejects ink onto a recording medium, wherein the ink is the ink according to claim 1.   5. An ink jet recording method comprising a discharge step of discharging ink onto a recording medium, wherein the ink is the ink according to any one of claims 1 to 4.   The inkjet according to claim 8, wherein after the pretreatment liquid containing a flocculant is applied to the recording medium, the ink according to any one of claims 1 to 4 is ejected onto the recording medium. Recording method.   A recorded matter comprising an image formed using the ink according to any one of claims 1 to 4 on a recording medium.

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