JP2002275403A - Ink composition, method for producing the same, ink jet recording device, method for recording and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photo-setting type ink composition for ink jet recording capable of imparting good dispersion stability, membrane strength and chemical resistance to a recording medium in a method for ink jet recording by which the ink composition is brought into contact with the recording medium and a photo-setting reaction is carried out to perform printing. SOLUTION: This photo-setting type ink composition for ink jet recording comprises at least a colorant, a photopolymerizable resin, a photopolymerization initiator, an aqueous solvent and a reactive surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable ink composition for ink jet recording and an ink jet recording method using the same.

2. Description of the Related Art An ink jet recording method is a printing method in which small droplets of an ink composition are made to fly and adhere to a recording medium such as paper to perform printing. This inkjet recording method,
The feature is that high-resolution, high-quality images can be printed at high speed. The ink composition used in the ink jet recording method generally contains an aqueous solvent as a main component, and further contains a coloring agent component and a wetting agent such as glycerin for the purpose of preventing clogging.

On the other hand, paper hardly penetrating an aqueous ink composition,
Cloths or materials that do not penetrate metal, plastic, etc.
For example, phenol, melamine, vinyl chloride, acrylic,
When printing on a recording medium such as a plate or a film made of a resin such as polycarbonate, the ink composition includes
It is required to contain a component capable of stably fixing the colorant to the recording medium. In particular, when printing on a printed wiring board or the like, the ink composition is required to have fast drying properties, chemical resistance, and curability.

In response to such a demand, an ink composition containing a component which is polymerized by ultraviolet irradiation has been proposed (for example, Japanese Patent Application Laid-Open No. 3-216379).
issue). Further, an ultraviolet curable ink composition containing a coloring agent, an ultraviolet curing agent, a photopolymerization initiator and the like has been proposed (for example, US Pat. No. 5,623,001). According to these ink compositions and the inkjet recording method,
It is described that bleeding of the ink composition onto a recording medium can be prevented and image quality can be improved.

[0004] Specifically, in an ink jet recording method using an ink composition containing a component which is polymerized by applying ultraviolet light, an ink composition is adhered to a recording medium, and then the ultraviolet light is applied to the recording medium. Is irradiated. Then, the photopolymerization initiator in the ink composition generates radicals and the like, whereby the oligomer and the monomer start polymerization, and the polymer fixes the colorant in the ink composition on the recording medium.
Due to this fixation, film strength, solvent resistance and color density are high,
It is considered that printing with less bleeding and unevenness can be realized. In addition, an ink composition for ink jet recording using such an ink composition may be referred to as a “photocurable ink composition for ink jet recording”.

Further, in order to prevent separation of a dye as a colorant, to improve abrasion resistance and printing reliability, to prevent bleeding after printing, and to improve ink drying property, an ink composition containing a colorant is polymerized. An ink jet recording ink composed of two liquids and a reaction liquid containing an initiator, and an ink jet recording method for printing on a recording medium using these two liquids are disclosed (for example, JP-A-5-186725, JP-A-8-2
No. 18018).

[0006] Such two-part ink for ink-jet recording contains a photopolymerization initiator or a photocurable resin in either the ink composition or the reaction liquid. In this way, by dividing into two liquids, the ink composition and the reaction liquid, the dark reaction is suppressed, the ink composition and the reaction liquid can be stored for a long time, and printing with excellent light resistance and heat resistance can be performed. Is what you do.

[0007]

SUMMARY OF THE INVENTION The present inventors have recently proposed:
In the photocurable ink jet recording ink composition,
It has been found that the use of a reactive surfactant can significantly improve the dispersion stability of the ink, the wettability of the ink on a recording medium, and the printing stability. The present invention is based on this finding.

Accordingly, it is an object of the present invention to provide a photocurable ink composition for ink jet recording, which can provide good ink jet recording and a good image, and an ink jet recording method using the same.

[0009]

According to one aspect of the present invention, at least a colorant, a photopolymerizable resin, a photopolymerization initiator, an aqueous solvent, and a reactive surfactant are contained. Provided is a photocurable ink composition for inkjet recording.

Further, according to another aspect of the present invention,
An ink jet recording method for printing by attaching droplets of an ink composition to a recording medium, wherein the ink composition comprises a colorant, a photopolymerizable resin, a photopolymerization initiator, an aqueous solvent, There is provided an ink jet recording method characterized by using a photocurable ink composition for ink jet recording comprising at least a surfactant.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Ink Composition) The photocurable ink composition for ink jet recording according to the present invention comprises at least a colorant, a photopolymerizable resin, an aqueous solvent, and a reactive surfactant. Things. The ink composition according to the present invention exhibits high storage stability, has excellent wettability to a recording medium, can perform stable printing in an ink jet recording method, and has an excellent image strength and chemical resistance. It will be.

The reason for obtaining such an advantage is that the reactivity of the reactive surfactant with the photopolymerizable resin is lower than that of a general surfactant used to secure printing stability. Because it is good, the dispersibility of the colorant and the photopolymerizable resin is not lost, and the components constituting the other ink composition can be stably dissolved or dispersed. It is considered that the presence of the compound allows the crosslink density in the film to be increased.

(Reactive Surfactant) The reactive surfactant contained in the ink composition of the present invention has a radical polymerizable double bond in the molecule and is the same as a general surfactant. Surfactant with emulsification, dispersion and wetting functions.

The content of the reactive surfactant in the ink composition of the present invention is in the range of about 0.01 to 5% by weight, preferably in the range of about 0.1 to 5%.

(Photopolymerizable Resin) The ink composition of the present invention comprises an oligomer and a monomer in the photopolymerizable resin.

(Oligomer) The oligomer contained in the ink composition of the present invention is a molecule having a relative molecular mass of a medium size and a unit substantially or conceptually obtained from a molecule having a small relative molecular mass. A few times, typically about 2
It has a structure constituted by repetition of about 20 times. The oligomer used in the present invention is also called a photopolymerizable prepolymer, base lysine or acrylic oligomer.

Since the oligomer has one or several acryloyl groups as a functional group, it has a property of causing a polymerization reaction with a monomer or the like by irradiation of ultraviolet rays or the like to be crosslinked and polymerized.

The oligomer used in the present invention is:
For example, polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, oligoacrylate, alkyd acrylate, polyol acrylate, and the like may be mentioned according to the molecular structure constituting the skeleton, and polyester acrylate and polyurethane acrylate are preferred.

The oligomer used in the present invention has a molecular weight in the range of about 500 to 20,000, preferably in the range of about 500 to 10,000.

When the ink composition of the present invention contains an oligomer, the content of the oligomer in the ink composition is in the range of about 1 to 50% by weight, preferably 3 to 50% by weight.
The range is about 30% by weight.

(Monomer) The monomer contained in the ink composition of the present invention refers to a molecule that can be a structural unit of the basic structure of a polymer. The monomer used in the present invention is also called a photopolymerizable monomer, and includes monofunctional acrylate and methacrylate, polyfunctional acrylate and methacrylate.

The monomer has a structure of acrylate and methacrylate of a low molecular polyol, and is characterized by low viscosity and quick curability.

The monomers used in the present invention are typically diethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-
Hexanediol diacrylate, hydroxypiperic acid ester neopentinyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaeristol hexaacrylate, acroylmorpholine, 2-phenoxyethyl acrylate, hydrogen phthalate (2,2,
2-triacroyloxymethyl) ethyl, dipentaerythritol polyacrylate, dipentaeristol polyacrylate, and the like, and preferably, acroylmorpholine, 2-phenoxyethyl acrylate, hydrogen phthalate- (2,2, 2-triacloyloxymethyl) ethyl, dipentaerythritol polyacrylate,
Dipentaerythol polyacrylate.

The monomer used in the present invention has a molecular weight of about 100 to 3,000, preferably 100 to 3,000.
Those having a range of about 2,000 are used.

When the ink composition of the present invention contains a monomer, the content of the monomer in the ink composition is in the range of about 1 to 70% by weight, preferably in the range of about 3 to 50% by weight.

The oligomer and the monomer have the property of being three-dimensionally copolymerized. Therefore, the content of the oligomer or monomer in the ink composition needs to be determined in consideration of polymerization efficiency, polymerization rate, resistance shrinkage after polymerization, strength of a polymer film, and the like.

Specifically, in the ink composition of the present invention, the ratio between the content of the oligomer and the content of the monomer is 95: 5.
４０40: 60, preferably 90:10.
~ 50: 50.

(Photopolymerization Initiator) The ink composition of the present invention contains a photopolymerization initiator. The photopolymerization initiator in the present invention is, for example, one that absorbs ultraviolet rays in a region of about 250 nm to 450 nm and generates radicals or ions to initiate polymerization of oligomers and monomers.

The photopolymerization initiator used in the present invention is typically benzoin methyl ether,
Benzoin ethyl ether, isopropyl benzoin ether, isobutyl benzoin ether, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, benzyl, diethoxyacetophenone, benzophenone, chlorothioxanthone, 2-chlorothioxanthone, isopropyl Thioxanthone, 2-
Methylthioxanthone, polychlorinated polyphenyl, hexachlorobenzene and the like can be mentioned, and preferred are isobutylbenzoin ether and 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime.

[0031] Also, the Vicu- tures 10 and 30 (Stau
ffer Chemical), Irgacure
184, 651, 2959, 907, 369, 170
0, 1800, 1850, 819 (manufactured by Ciba Specialty Chemicals), Darocure 1173 (EM
Chemical), QuantacureCT
X, ITX (Aceto Chemical), L
A photopolymerization initiator available under the trade name of ucirin TPO (manufactured by BASF) can also be used.

(Colorant) The colorant contained in the ink composition of the present invention is a water-dispersible pigment and / or a water-dispersible dye.

As the pigment, an inorganic pigment or an organic pigment can be used. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, and a thermal method can be used.

Examples of the organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.) and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridones). Pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinoflurone pigments, etc., dye chelates (eg, basic dye type chelates,
Acid dye type chelates), nitro pigments, nitroso pigments, aniline black and the like.

As the dye, a dye having dispersibility which can be used for ink jet recording can be used.

The amount of the colorant added to the ink composition of the present invention is preferably 1 to 50% by weight, more preferably 2 to 3% by weight.
It is about 0% by weight.

According to a preferred embodiment of the present invention, the colorant is preferably added to the ink composition as a colorant dispersion obtained by dispersing the colorant in an aqueous medium with a dispersant or a surfactant. As a preferable dispersant, a dispersant commonly used for preparing a colorant dispersion liquid, for example, a polymer dispersant can be used. It will be apparent to those skilled in the art that the dispersant and surfactant contained in the colored dispersion also function as the dispersant and surfactant of the ink composition.

(Aqueous solvent and other components) The ink composition of the present invention comprises at least a colorant, a photopolymerizable resin, a photopolymerization initiator, an aqueous solvent, and a reactive surfactant.

In the ink composition of the present invention, the aqueous solvent preferably comprises water and a water-soluble organic solvent. As the water, pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, or distilled water, or ultrapure water can be used. In addition, it is preferable to use water sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like, since the generation of mold and bacteria can be prevented when the ink composition is stored for a long period of time.

The water-soluble organic solvent is preferably a low-boiling organic solvent, and examples thereof include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, and te.
rt-butanol, iso-butanol, n-pentanol and the like. Particularly, a monohydric alcohol is preferable. Low-boiling organic solvents have the effect of shortening the drying time of the ink. The addition amount of the low boiling organic solvent is preferably 0.1 to 10% by weight of the ink composition, more preferably 0.5 to 10% by weight.
-5% by weight.

According to a preferred embodiment of the present invention, the ink composition according to the present invention preferably further comprises a wetting agent comprising a high-boiling organic solvent. Preferred specific examples of the high-boiling organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, and glycerin. , Trimethylolethane, polyhydric alcohols such as trimethylolpropane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether,
Alkyl ethers of polyhydric alcohols such as diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, urea, 2-pyrrolidone, N-methyl-2- Pyrrolidone,
1,3-dimethyl-2-imidazolidinone and the like. The amount of these wetting agents added is 0.5% of the ink composition.
Preferably, it is in the range of 2 to 20% by weight.

Further, as an optional component, a polyvalent metal salt,
Or polyallylamine or a derivative thereof, a resin emulsion, an inorganic oxide colloid, a wetting agent, a pH adjuster,
Preservatives, fungicides and the like may be added.

(Manufacturing Method of Ink Composition) In the manufacturing method of the ink composition for ink jet recording according to the present invention, a monomer, a photopolymerization initiator and a reactive surfactant are dissolved and dispersed in an oligomer, and then colored. The method comprises adding an agent and an aqueous solvent.

According to the method for producing an ink composition of the present invention, storage stability is high, printing stability at the time of ink-jet recording, film strength of a printed material on a recording medium,
The above ink composition for ink jet recording having excellent chemical resistance can be obtained.

In the method for producing the ink composition of the present invention, first, a product obtained by dissolving a monomer, an initiator and a reactive surfactant is dissolved in an oligomer and mixed. Thereby, a highly compatible dispersion solution can be obtained.

According to a preferred embodiment of the present invention, a dispersion solution is obtained by slowly dropping and dissolving a solution of a monomer, an initiator and a reactive surfactant while stirring the oligomer, and mixing. Is preferred.

After preparing a dispersion solution comprising an oligomer, a monomer, a photopolymerization initiator and a reactive surfactant, a colorant, an aqueous solvent and optional components are added to the dispersion solution. According to a preferred embodiment of the present invention, when the above components are added to the prepared dispersion solution, light (particularly, ultraviolet light) is blocked so that the oligomer, the monomer, and the reactive surfactant do not start the polymerization reaction by the photopolymerization initiator. It is preferable to carry out under the following conditions.

In the method for producing an ink composition according to the present invention, a stirrer commonly used for producing an ink composition can be used.

(Inkjet Recording Method) The inkjet recording method according to the present invention comprises a colorant, an oligomer,
Printing is performed on a recording medium using a photocurable ink composition for inkjet recording, which comprises at least a monomer, a photopolymerization initiator, an aqueous solvent, and a reactive surfactant.

According to the ink jet recording method of the present invention, printing is performed using the above-described photocurable ink jet recording ink composition, so that good image quality and good printing can be obtained.

Further, in the ink jet recording method of the present invention, after the ink composition is adhered to a recording medium,
Irradiate with light. The irradiated light causes the photopolymerization initiator to generate radicals and the like, whereby the oligomer, the monomer, and the reactive surfactant start a polymerization reaction to fix the colorant in the ink composition to the recording medium. It is considered that this makes it possible to perform clear printing with excellent film strength and chemical resistance even on a medium surface that cannot penetrate an aqueous medium such as a metal or a plastic. The light irradiation may be visible light irradiation or ultraviolet irradiation, particularly preferably ultraviolet irradiation.

According to a preferred embodiment of the present invention, when performing ultraviolet irradiation, the amount of ultraviolet irradiation is 100 mJ / cm ² or more, preferably 500 mJ / cm ² or more.
10,000 mJ / cm ² or less, preferably 5,000
The treatment is performed in the range of mJ / cm ² or less. An ultraviolet irradiation amount within such a range is advantageous because the curing reaction can be sufficiently performed and the colorant can be prevented from fading due to the ultraviolet irradiation.

The ultraviolet irradiation includes lamps such as a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low-pressure mercury lamp, and a high-pressure mercury lamp. For example, it can be performed by using a commercially available lamp such as an H lamp, a D lamp, and a V lamp manufactured by Fusion System.

In the ink jet recording method according to the present invention, heating may be performed before, simultaneously with, or after light irradiation.

When an ink composition containing an aqueous solvent as an optional component is adhered to a recording medium, the polymerization reaction can be efficiently performed by removing water remaining on the recording medium, particularly by using a heating means. . As a result, it is possible to enhance the fixation of the printed matter printed on the recording medium and improve the film strength and the chemical resistance.

The heating may be performed by heating the recording medium by bringing it into contact with a heat source, infrared rays or microwaves (2,450 Mh).
(electromagnetic wave having a maximum wavelength of about z) or a method of heating without contacting the recording medium, such as blowing hot air.

Hereinafter, embodiments of the present invention will be described.

(Example 1) Aqueous titanium oxide dispersion (pigment content 55% by weight) 28% by weight Urethane oligomer (aqueous urethane resin dispersion, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (IRGACURE 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Aqualon RN-20, Daiichi Kogyo) 0.1% by weight Ethylene glycol 5% by weight Water 37.9% by weight (Example 2) Aqueous titanium oxide dispersion (pigment content 55% by weight) 28% by weight Urethane oligomer (aqueous urethane resin dispersion) Body, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Aqualon RN-20, Daiichi Kogyo) 1.0% by weight Ethylene glycol 5% by weight Water 37% by weight (Example 3) Aqueous titanium oxide dispersion (pigment content 55% by weight) 28% by weight Urethane-based oligomer (aqueous urethane resin dispersion, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Aqualon RN-20, Daiichi Kogyo) 3.0 wt% ethylene glycol 5 wt% water 35 wt% (Example 4) aqueous titanium oxide dispersion (pigment content 55 wt%) 28 wt% urethane oligomer (aqueous urethane resin dispersion, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Aqualon RN-20, Daiichi Kogyo) 5.0 wt% ethylene glycol 5 wt% water 33 wt% (Example 5) aqueous titanium oxide dispersion (pigment content 55 wt%) 28 wt% urethane oligomer (aqueous urethane resin dispersion, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Aqualon HS-10, Daiichi Kogyo) 1.0% by weight Ethylene glycol 5% by weight Water 37% by weight (Example 6) Aqueous titanium oxide dispersion (pigment content 55% by weight) 28% by weight Urethane-based oligomer (aqueous urethane resin dispersion, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Aqualon HS-10, Daiichi Kogyo) (Manufactured by Pharmaceutical Co., Ltd.) 3.0% by weight Ethylene glycol 5% by weight Water 35% by weight (Example 7) Aqueous oxidized carbon black dispersion (pigment content 30% by weight)
30% by weight urethane oligomer (aqueous urethane resin dispersion, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Aqualon RN-20, Daiichi Kogyo) 3.0% by weight Ethylene glycol 5% by weight Water 33% by weight (Comparative Example 1) Aqueous titanium oxide dispersion (pigment content 55% by weight) 28% by weight Urethane oligomer (aqueous urethane resin dispersion, NR
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (HITENOL N08, Daiichi Kogyo Pharmaceutical Co., Ltd.) 3.0% by weight Ethylene glycol 5% by weight Water 35% by weight (Comparative Example 2) Aqueous titanium oxide dispersion (pigment content 55% by weight) 28% by weight Urethane oligomer (aqueous urethane resin dispersion, NR)
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Reactive surfactant (Neugen EA170, Daiichi Kogyo Pharmaceutical Co., Ltd.) 3.0% by weight Ethylene glycol 5% by weight Water 35% by weight (Comparative Example 3) Aqueous titanium oxide dispersion (pigment content 55% by weight) 28% by weight Urethane oligomer (aqueous urethane resin dispersion, NR)
-445, manufactured by Zeneca Corporation) 20% by weight monomer (dipentaerythritol polyacrylate,
A-9530, manufactured by Shin-Nakamura Chemical Co., Ltd.) 8% by weight Photopolymerization initiator (Irgacure 1700, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0% by weight Ethylene glycol 5% by weight Water 38% by weight Described in Examples The amount of the various materials to be added is not limited to the amount, and the aqueous titanium oxide dispersion may be 3 to 3 times.
5% by weight, 3-60% by weight of aqueous carbon black dispersion, 3-30% by weight of urethane oligomer, 3-10% by weight of monomer, and 0.3-2% by weight of initiator make ink. And the effect of the addition of the reactive surfactant can be similarly obtained.

The method for evaluating the ink composition having the above composition is described below.

(Evaluation Test) The ink composition having the above composition was filled in a recording head of an ink jet recording apparatus and adhered onto paper as a recording medium and a printed circuit board to evaluate printing. In the case of a printed circuit board, after drying at 50 ° C. for 10 minutes, ultraviolet irradiation was performed at an irradiation amount of 500 mJ / cm ² .

As an ink jet recording apparatus, an ink jet printer MJ510C (manufactured by Seiko Epson Corporation) was used. The irradiation lamp used for ultraviolet irradiation was a metal halide type lamp having a wavelength of 365 nm.

The ink composition and the printed matter printed on the recording medium were evaluated by performing the following tests.

Evaluation 1 : Evaluation of Surface Tension Measurement The ink composition having the above composition was measured with a surface tensiometer (DCVP-Z, manufactured by Kyowa Interface Science).

Evaluation 2 : Dispersion stability test The ink composition of the above composition was stored in a glass sample bottle at room temperature (about 25 ° C.) for 1 week in a light-shielded state, and the state of the precipitate was observed. ：: No precipitate Δ: Slight precipitate (one layer precipitate at bottom of bottle) ×: Precipitate evaluated 3 : Print diameter evaluation test
J510C (manufactured by Seiko Epson Corporation) was used to discharge only one dot from one nozzle onto a printed circuit board, and the printing diameter formed at that time was measured.

Evaluation 4 : Pencil hardness test For the printed matter printed on the recording medium, JIS K54
The hardness of the printed matter was evaluated by the method specified in 00 (pencil scratch test handwriting method).

Evaluation 5 : Chemical resistance test The printed matter printed on the recording medium was immersed in ethanol for 5 minutes, taken out, and rubbed back and forth five times with a toothbrush. The evaluation was performed according to the following criteria. ：: did not peel off. Δ: Partially peeled off. X: All peeled off. The results of the tests performed on the ink compositions of Examples 1 to 7 and Comparative Examples 1 to 3 are as shown in Table 1 below. Table 1 Evaluation 1 Evaluation 2 Evaluation 3 Evaluation 4 Evaluation 5 Surface tension Dispersion stability Printing diameter Pencil hardness Ethanol resistance [mN / m] [μm] Example 1 35.0 ○ 954H △ Example 2 31.0 ○ 100 4H ○ Example 3 30.0 ○ 105 5H ○ Example 4 29.5 ○ 105 5H ○ Example 5 30.5 ○ 100 4H ○ Example 6 29.0 ○ 100 5H ○ Example 7 28.5 ○ 105 5H ○ Comparative example 1 30.5 × 105 2H △ Comparative example 2 30.0 △ 105 2H △ Comparative example 3 43.0 × 803 3H △

[0066]

As described above, according to the ink composition of the present invention, good printability on a recording medium, dispersion stability,
Excellent film strength can be obtained while maintaining adhesion. Further, when character characters were printed at 360 dpi on a printed circuit board using the ink composition of the present invention,
A good printing state can be obtained without a gap in the character.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA13 FC01 HA44 2H086 BA01 BA53 BA55 BA59 BA62 4J039 AD21 AE04 AE05 AE06 AE07 BA04 BA13 BA35 BA37 BC05 BC07 BC09 BC12 BC13 BC16 BC36 BC37 BC39 BC48 BC50 BC51 BC55 BC60 BC67 BC72 BE01 BE12 BE22 BE27 CA06 DA02 EA06 EA40 EA42 EA44 GA24

Claims (10)

[Claims] 1. A photocurable ink composition for inkjet recording, comprising at least a colorant, a photopolymerizable resin, a photopolymerization initiator, an aqueous solvent, and a reactive surfactant. 2. The ink composition according to claim 1, wherein the reactive surfactant has a radical polymerizable double bond. 3. The content of the reactive surfactant is 0.01%.
The ink composition according to claim 1, wherein the content is from 5 to 5% by weight. 4. The photopolymerizable resin according to claim 1, wherein the material comprises at least an oligomer and a monomer.
5. The ink composition according to any one of 4. 5. A method for producing an ink composition, comprising at least a coloring agent, a photopolymerizable resin, a photopolymerization initiator, an aqueous solvent, and a reactive surfactant, wherein the oligomer comprises a monomer and a monomer. A method for producing an ink composition, comprising: a step of dissolving the photopolymerization initiator and a reactive surfactant; and a step of adding the colorant and the aqueous solvent. 6. An ink jet recording apparatus for recording by attaching an ink composition to a recording medium, comprising at least the ink composition according to claim 1. Description: 7. An ink jet recording method for performing recording by discharging an ink composition containing at least a colorant, a photopolymerizable resin, a photoinitiator, an aqueous solvent, and a reactive surfactant by an ink jet apparatus. An ink jet recording method comprising at least a step of attaching a substance to a recording medium and a step of curing the attached ink composition. 8. The ink jet recording method according to claim 7, wherein the curing reaction is performed by irradiating an ultraviolet ray. 9. The method according to claim 1, wherein the irradiation of the ultraviolet rays is 100 to 10,000 m.
9. The recording method according to claim 8, wherein the recording is performed at an irradiation dose of J / cm < ² >. 10. A recording medium printed by the recording method according to claim 6.