JP2009220582A - Inkjet recording method - Google Patents

Abstract

A coloring material contained in a printed material is decomposed by the action of radicals generated from an oxidizing substance, a corrosive substance, or a photopolymerization initiator in light or air without inhibiting the ultraviolet curing action of the ink. The obtained printed matter has a high mechanical durability, a good color preservability, and an ink jet recording method free from fading.
An ink composition A containing at least a coloring material, an ultraviolet absorber and an antioxidant, and an ink composition B containing at least a photopolymerization initiator, a polymerizable compound and a polymerization accelerator on a recording medium. And then printing by irradiating with ultraviolet rays. A pigment is preferable as the color material, and fine particles having a polymerizable functional group are preferable as the polymerization accelerator.
[Selection figure] None

Description

  The present invention relates to an inkjet recording method, and more particularly to an inkjet recording method using a two-component ink composition.

The ink jet recording method is a printing method in which printing is performed by causing a droplet of an ink composition to fly and adhere to a recording medium such as paper. This ink jet recording method is characterized in that a high-resolution and high-quality image 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 contains a coloring component and a wetting agent such as glycerin for the purpose of preventing clogging.
On the other hand, recording media such as paper and fabrics that are hard to penetrate water-based ink compositions, or materials such as metals, plastics, and the like that do not penetrate, such as plates and films produced from resins such as phenol, melamine, vinyl chloride, acrylic, and polycarbonate. When printing on the ink composition, the ink composition is required to contain a component capable of stably fixing the colorant to the recording medium.

In response to such a requirement, an ultraviolet curable inkjet ink containing a colorant, an ultraviolet curing agent (polymerizable compound), a (photo) polymerization initiator, and the like is disclosed (for example, see Patent Document 1). . According to this ink, it is said that the ink can be prevented from bleeding into the recording medium and the image quality can be improved. The ultraviolet curable ink described in Patent Document 1 was a one-component type.
In addition, the color material contained in the printed material is light (especially ultraviolet rays), oxidizing substances in the air (for example, ozone, NO _x , SO _x , formaldehyde, etc.), corrosive substances (for example, ammonia, etc.), light It may be decomposed by the action of radicals generated from the polymerization initiator. In order to prevent this, an ultraviolet absorber or an antioxidant is added to the ink composition.

US Pat. No. 5,562,001

However, the addition of an ultraviolet absorber or an antioxidant to a one-component ultraviolet curable ink composition has a problem in that the ultraviolet curing action of the ink itself is hindered.
The ultraviolet absorber itself absorbs ultraviolet rays to reduce the efficiency of the photopolymerization initiator, and the antioxidant suppresses the influence of active oxygen that causes photodegradation (the generation of radicals associated therewith). Both result in inhibition of the polymerization reaction.
The present invention overcomes the above-mentioned drawbacks of the prior art, and the color material contained in the printed matter is derived from an oxidizing substance, corrosive substance, or active oxygen in the light or air without inhibiting the ultraviolet curing reaction of the ink. The printed matter obtained without being decomposed by the action of radicals is intended to provide an ink jet recording method having excellent mechanical durability, good preservation of the printed matter, and less fading.

As a result of intensive studies, the present inventor has achieved the above object by adopting the following configuration, and has achieved the present invention.
That is, the present invention is as follows.
(1) An ink composition A containing at least a colorant, an ultraviolet absorber and an antioxidant on a recording medium; an ink composition B containing at least a photopolymerization initiator, a polymerizable compound and a polymerization accelerator; An ink-jet recording method comprising printing after irradiation with ultraviolet light after adhering to the surface.
(2) The inkjet recording method according to (1), wherein the color material is a pigment.
(3) The inkjet recording method according to (1), wherein the polymerization accelerator is a fine particle having a polymerizable functional group.

In the ink jet recording method of the present invention, the ink to be used is divided into two liquids, one containing a coloring material, an ultraviolet absorber and an antioxidant (ink composition A), and the other containing a photopolymerization initiator and a polymerizable compound. And a polymerization accelerator (ink composition B). Immediately after the ink composition A is ejected onto the recording medium, the ink composition B is ejected and then irradiated with ultraviolet rays. Thereby, the ink composition A forms a color material layer on the recording medium, and the ink composition B forms a protective layer on the color material layer. The color material layer is not affected by the oxidizing and corrosive substances in the light and air due to the effect of the ultraviolet absorber and the antioxidant, and the protective layer contains the ultraviolet absorber and the antioxidant. Since it does not contain, UV curing (photopolymerization) is not inhibited.
Therefore, the printed matter obtained by the ink jet recording method of the present invention has excellent mechanical durability, good preservation of the printed matter, and less discoloration.

It is a figure which shows the inkjet recording device preferably used for implementation of the inkjet recording method by this invention.

Hereinafter, the ink jet recording method of the present invention will be described in detail.
The ink jet recording method of the present invention comprises an ink composition A containing at least a colorant, an ultraviolet absorber and an antioxidant, and an ink composition B containing at least a photopolymerization initiator, a polymerizable compound and a polymerization accelerator. 2 liquids are used.
The ink composition A is simply referred to as an “ink composition” because it contains a color material, and the ink composition B is sometimes referred to as a “transparent ink composition” because it does not contain a color material.

The color material contained in the ink composition A used in the ink jet recording method of the present invention may be either a dye or a pigment, but the pigment is more advantageous from the viewpoint of the durability of the printed matter.
As dyes used in the present invention, direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, soluble vat dyes, reactive disperse dyes, etc. are usually used for inkjet recording. Various dyes can be used.

As the pigment used in the present invention, inorganic pigments and organic pigments can be used without any particular limitation.
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, or a thermal method can be used. _The organic pigments include azo pigments (azo _lakes, including insoluble azo pigments, condensed azo pigments, and chelate azo pigment), polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine Pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelates, acidic dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

According to a preferred embodiment of the present invention, these pigments are preferably added to the ink composition A as a pigment dispersion obtained by dispersing the pigment in an aqueous medium with a dispersant or a surfactant. As a preferable dispersant, a dispersant conventionally used for preparing a pigment dispersion, for example, a polymer dispersant can be used. It will be apparent to those skilled in the art that the dispersant and the surfactant contained in the pigment dispersion also function as the dispersant and the surfactant of the ink composition A.
The addition amount of the coloring material in the ink composition A is preferably in the range of about 0.1 to 25% by weight, more preferably in the range of about 0.5 to 15% by weight.

Next, the ultraviolet absorber and antioxidant contained in the ink composition A used in the ink jet recording method of the present invention will be described.
The ultraviolet absorber and the antioxidant contained in the ink composition A used in the ink jet recording method of the present invention are not particularly limited, and those publicly known and publicly used can be used.
For example, examples of the ultraviolet absorber include cinnamic acid derivatives (octyl methoxycinnamate), dibenzoylmethane derivatives (t-butylmethoxybenzoyl), paraaminobenzoic acid derivatives (octyl dimethylparaaminobenzoate), benzophenone compounds, and the like. It is done. Examples of benzophenone compounds include KEMISORB 10, 11, 11S, 12, 111, 1001, 1011 (registered trademark, manufactured by Chemipro Kasei Co., Ltd.) as a commercial product.

Antioxidants include dimethylaminostyryl heptylmethylthiazolium iodide, vitamin C, vitamin C dipalmitate, vitamin C stearate, vitamin C tetrahexyldecanol, vitamin C palmitate, vitamin C magnesium phosphate, vitamin E, vitamin E acetate , Rutin, enzyme-treated isoquercitrin, myricitrin, hindered phenol compounds and the like. Examples of rutin include Rutin K-2 (registered trademark manufactured by Kiriya Chemical Co., Ltd.) as a commercial product. As a hindered phenol compound, Irganox 1076 (registered trademark, manufactured by Ciba Specialty Chemicals Co., Ltd.) can be mentioned as a commercial product.
Moreover, what has the function as a ultraviolet absorber and antioxidant by 1 agent can also be used. As such one agent having a function as an ultraviolet absorber and an antioxidant, Sanmerin (registered trademark, manufactured by San-Ei Gen FFI Co., Ltd.) can be mentioned as a commercial product.
The addition amount of the ultraviolet absorber and the antioxidant in the ink composition A is not particularly limited, but is preferably in the range of about 0.01 to 5.0% by weight, more preferably in the range of about 0.05 to 1.0% by weight.

  The ink composition A of the present invention may contain an aqueous solvent. Furthermore, resin emulsions, inorganic oxide colloids, wetting agents, pH adjusting agents, preservatives, fungicides and the like may be added as optional components.

The photopolymerization initiator contained in the ink composition B used in the ink jet recording method of the present invention is, for example, a radical or ion that absorbs ultraviolet rays or visible light in the region of about 200 nm to 450 nm to form a polymerizable compound. Polymerization is initiated.
Typical photopolymerization initiators used in the ink composition B of the present invention include 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, isopropylthioxanthone, 2-methylthioxanthone, polychlorinated polyphenyl, hexachlorobenzene, etc., preferably isobutylbenzoin Ether, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime.

  Also, Vicure 10, 30 (manufactured by Stauffer Chemical), Irgacure 184, 651, 2959, 907, 369, 1700, 1800, 1850, 819 (manufactured by Ciba Specialty Chemicals), Darocur 1173 (manufactured by EM Chemical), QuantITX Photopolymerization initiators available under the trade names of (Aceto Chemical) and Lucirin TPO (BASF) can also be used.

The polymerizable compound contained in the ink composition B used in the ink jet recording method of the present invention is not particularly limited as long as it is polymerized by radicals or ions generated from a photopolymerization initiator, such as an oligomer or a monomer. is there.
The oligomer contained in the ink composition B of the present invention is a molecule having a medium relative molecular mass and is obtained by repeating a unit of a number of times substantially or conceptually obtained from a molecule having a small relative molecular mass. It has a structured structure. The oligomer used in the present invention is also called a photopolymerizable prepolymer, base resin or acrylic oligomer.

  Examples of the oligomer used in the present invention include polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, oligo acrylate, alkyd acrylate, polyol acrylate and the like depending on the molecular structure constituting the skeleton, preferably polyester acrylate, polyurethane Acrylate.

The monomer contained in the ink composition B of the present invention refers to a molecule that can be a structural unit of a basic structure of a polymer. The monomers used in the present invention are also called photopolymerizable monomers, and include monofunctional acrylates and polyfunctional acrylates.
Representative monomers used in the present invention include diethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, hydroxypioperic acid ester neopentine glycol glycol diacrylate, and trimethylolpropane triacrylate. , Pentaerythritol triacrylate, dipentaerythrole hexaacrylate, acroylmorpholine, 2-phenoxyethyl acrylate, hydrogen phthalate- (2,2,2-triacroyloxymethyl) ethyl, dipentaerystol polyacrylate, Dipentaerystol polyacrylate, N-vinylformamide, tripropylene glycol diacrylate, glycerin EO adduct triacrylate, and the like are listed. Acroylmorpholine, 2-phenoxyethyl acrylate, hydrogen phthalate- (2,2,2-triacroyloxymethyl) ethyl, dipentaerystol polyacrylate, dipentaerystol polyacrylate, N-vinyl Formamide, tripropylene glycol diacrylate, glycerin EO adduct triacrylate.

The monomer used in the present invention has a molecular weight in the range of about 100 to 3,000, preferably in the range of about 100 to 2,000.
When the ink composition B of the present invention contains a monomer, the content of the monomer in the ink composition B 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 a property of being copolymerized to be three-dimensional. Therefore, the content of the oligomer or monomer in the ink composition B needs to be determined in consideration of the polymerization efficiency, the polymerization rate, the resistance shrinkage after polymerization, the strength of the polymer film, and the like.

  Although it does not specifically limit as a polymerization accelerator contained in the ink composition B used for the inkjet recording method of this invention, Darocure EHA, EDB (made by Ciba Specialty Chemicals) etc. are mentioned.

Examples of other polymerization accelerators include fine particles having a polymerizable functional group.
Although the mechanism of action of the fine particles having a polymerizable functional group is not clear, the radicals generated by the photopolymerization initiator that has absorbed and cleaved ultraviolet rays are adsorbed and stabilized on the fine particle surface, and polymerization is introduced to the fine particle surface. It is presumed that the polymerization reaction is promoted by easily starting the reaction with the functional functional group and the monomer adsorbed on the surface.

The fine particles having a polymerizable functional group are not particularly limited, but are generally called extender pigments, and examples thereof include inorganic compounds such as silica, alumina, titania, calcium oxide, and particularly, silica, alumina, and the like. Transparent materials can also be suitably used.
The polymerizable functional group possessed by the fine particles is not particularly limited, and examples thereof include an acryloyl group and a methacryloyl group, and can also be a polymerizable functional group having one or more double bonds. .
The size of the fine particles is not particularly limited, but those having a particle size of 10 to 100 nm are preferable.
The method for preparing the fine particles having a polymerizable functional group is not particularly limited, but silica fine particles having a large number of hydroxyl groups are produced by a sol-gel reaction of a silane compound such as tetraethoxysilane, and the polymerizable functional group is imparted to the hydroxyl groups. The method of making it react with such a compound is mentioned.
The content of the fine particles having a polymerizable functional group in the ink composition B of the present invention is not particularly limited, and is appropriately selected according to the use form, conditions, the relationship between the viscosity and the polymerizable property of the ink composition, and the like. Although it should be, it is preferably 10% by mass or less based on the total amount of the ink composition.

The ink composition B of the present invention may contain an aqueous solvent. Furthermore, as an optional component, a polyvalent metal salt, polyallylamine or a derivative thereof, a wetting agent, a pH adjusting agent, a preservative, a fungicide, or the like may be added.
In addition, the ink compositions A and B of the present invention preferably have a difference in viscosity at 25 ° C. of 2 mPa · s or less in view of handling in ink jet recording.
In addition, the ink compositions A and B of the present invention are preferably solvent-free ink compositions that do not contain an organic solvent.

In the ink jet recording method of the present invention, the ink composition A is discharged onto a recording medium, immediately after that, the ink composition B is discharged, and then ultraviolet rays are irradiated.
The dose of ultraviolet rays, 10 mJ / cm ² or more and 10,000 / cm ² or less, and preferably 50 mJ / cm ² or more, conducted at 6,000 mJ / cm ² or less. If it is the amount of ultraviolet irradiation within such a range, a sufficient curing reaction can be performed.

Examples of the ultraviolet irradiation include lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low pressure mercury lamps, and high pressure mercury lamps. For example, a commercially available product such as an H lamp, D lamp, or V lamp manufactured by Fusion System can be used.
Further, ultraviolet irradiation can be performed by an ultraviolet light emitting semiconductor element such as an ultraviolet light emitting diode (ultraviolet LED) or an ultraviolet light emitting semiconductor laser.

  In the ink jet recording method of the present invention, heating may be performed before, simultaneously with, or after the irradiation with ultraviolet light. Heating is performed by bringing a recording medium into contact with a heat source, heating without irradiating the recording medium, such as irradiating infrared rays or microwaves (electromagnetic waves having a maximum wavelength of about 2,450 Mhz), or blowing hot air. The method etc. are mentioned.

Further, a recording apparatus for performing the ink jet recording method according to the present invention will be described.
The ink jet recording apparatus of FIG. 1 has means for adhering ink composition A and ink composition B to a recording medium, a drive system for the means for adhering them, means for moving the recording medium, and irradiating the recording medium with ultraviolet rays. And heating means, and cleaning means.
The recording head 1 a (and 1 b) connected to the ink tank 2 a having the ink composition A and the ink tank 2 b having the ink composition B by the tube 3 according to the present invention is driven by the motor 5 along the carriage 4. It moves in the direction of arrow A by the timing belt 6. During the movement, the ink composition A is discharged from the nozzle surface of the recording head 1 a and adheres to the recording medium 7 placed at a position facing the recording head 1 a by the platen 8 and the guide 9. Next, the recording medium 7 is transferred to the paper feed direction arrow B by a predetermined amount. Meanwhile, the recording head 1a (and 1b) moves in the direction opposite to the arrow A in the drawing and returns to the left end position of the recording medium 7. Then, the ink composition B is ejected from the nozzle surface of the recording head 1b onto the recording medium to which the ink composition A has already adhered, and printing is performed. The printed recording medium 7 is further transferred by a predetermined amount in the paper feed direction arrow B, and is subjected to ultraviolet irradiation by the ultraviolet irradiation means 15 and heat treatment by the heater 14. On the surface of the recording medium 7 that has undergone these treatments, the ink composition A and the ink composition B undergo a curing reaction, and the coloring material is fixed on the recording medium 7. The recording medium 7 subjected to the printing process is further transferred to the paper feed direction arrow B. In addition, this apparatus has a cap 10 to which a suction pump 11 is connected, and a cleaning operation is performed by these mechanisms. The sucked ink composition or the like is stored in the waste ink tank 13 through the tube 12.

Hereinafter, the present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.
1. Ink composition A

(Yellow Pigment Ink Composition 1 (Y1))
C. I. Pigment Yellow 74 (coloring material) 3.5wt%
Styrene-acrylic acid copolymer (dispersant) 1wt%
Glycerin 5wt%
Triethylene glycol 3wt%
Triethanolamine 1wt%
Surfynol 465 (surfactant, Air Product and Chemicals, Inc.) 1 wt%
KEMISORB 11S (Kemipro Kasei Co., Ltd., water-soluble UV absorber)
0.5wt%
Rutin K-2 (Kiriya Chemical Co., Ltd., water-soluble antioxidant) 0.05 wt%
Ion exchange water

(Yellow Pigment Ink Composition 2 (Y2)
C. I. Pigment Yellow 74 (coloring material) 3.5wt%
Styrene-acrylic acid copolymer (dispersant) 1wt%
Glycerin 5wt%
Triethylene glycol 3wt%
Triethanolamine 1wt%
Surfynol 465 (surfactant, manufactured by Air Product and Chemicals, Inc.) 1 wt%
Ion exchange water

2. Preparation of ink composition An ink composition having the above composition was prepared. The preparation was performed as follows.
A pigment, a dispersant, and ion-exchanged water, which are coloring materials, are mixed and dispersed in a sand mill (manufactured by Yasukawa Seisakusho) with glass beads (diameter 1.7 mm, 1.5 times the weight of the mixture (weight)) for 2 hours. It was. Thereafter, the glass beads were disassembled to prepare a pigment dispersion.
Next, a solvent excluding the pigment and the dispersant is mixed to form an ink solvent, and the ink dispersion is gradually dropped while stirring the pigment dispersion, followed by stirring at room temperature for 20 minutes, and then with a membrane filter having a pore size of 5 μm. Filtration was performed to obtain an ink composition A for ink jet recording.

3. Transparent ink composition B
(Transparent ink composition 1 (T1))
N-vinylformamide (Beamset 770 Arakawa Chemical Industries) 53 wt%
Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toa Gosei Co., Ltd.) 25wt%
Glycerin EO adduct triacrylate (NK ester A-Gly-3E, Shin-Nakamura Chemical Co., Ltd.) 10wt%
Irgacure 819 (Ciba Specialty Chemicals Co., Ltd.) 1.5wt%
Irgacure 369 (Ciba Specialty Chemicals Co., Ltd.) 3.5wt%
Darocur EHA (Ciba Specialty Chemicals Co., Ltd.) 1.0wt%
Polymerizable fine particle 1 6.0 wt%

Production method of polymerizable fine particles 1 Silica sol IPA-ST (manufactured by Nissan Chemical Industries, Ltd., isopropyl alcohol (hereinafter referred to as IPA) dispersion having a silica concentration of 30 wt%) 88.1 parts by weight was added to a 200 mL Erlenmeyer flask, and silane coupling was performed. Agent 7.9 parts by weight of Sila Ace S710 (manufactured by Chisso Corporation) was added. While stirring with a magnetic stirrer, 4 parts by weight of 0.05 mol / L hydrochloric acid was added, and the reaction was carried out with stirring for 24 hours at room temperature. As a result, an IPA dispersion A containing polymerizable fine particles 1 was obtained.

Production Method of Transparent Ink Composition 1 To a 300 mL round bottom flask, 70 parts by weight of N-vinylformamide (hereinafter referred to as NVF) and 100 parts by weight of dispersion A are added, IPA is distilled off using a rotary evaporator, and polymerizable fine particles 1 are obtained. Monomer solution B containing 30 wt% was obtained.
Subsequently, 20 parts by weight of this monomer solution B was added to a 100 mL light-shielding sample bottle, 39 parts by weight of NVF, 25 parts by weight of tripropylene glycol diacrylate, 10 parts by weight of glycerin EO adduct triacrylate, Irgacure 819 1.5. A transparent ink composition 1 was prepared by adding parts by weight, 3.5 parts by weight of Irgacure 369, and 1.0 parts by weight of Darocur EHA and stirring for 1 hour with a magnetic stirrer.

(Transparent ink composition 2 (T2))
N-vinylformamide (Beamset 770 Arakawa Chemical Industries, Ltd.) 59wt%
Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toa Gosei Co., Ltd.) 25wt%
Glycerin EO adduct triacrylate (NK ester A-Gly-3E manufactured by Shin-Nakamura Chemical Co., Ltd.) 10wt%
Irgacure 819 (Ciba Specialty Chemicals Co., Ltd.) 1.5wt%
Irgacure 369 (Ciba Specialty Chemicals Co., Ltd.) 3.5wt%
Darocur EHA (Ciba Specialty Chemicals Co., Ltd.) 1.0wt%

Production Method of Transparent Ink Composition 2 In a 100 mL light-shielding sample bottle, 59 parts by weight of NVF, 25 parts by weight of tripropylene glycol diacrylate, 10 parts by weight of glycerol EO adduct triacrylate, 1.5 parts by weight of Irgacure 819, Irgacure 369 3 0.5 part by weight and 1.0 part by weight of Darocur EHA were added and stirred for 1 hour with a magnetic stirrer to prepare a transparent ink composition 2.

(Transparent ink composition 3 (T3))
N-vinylformamide
(Beam Set 770 Arakawa Chemical Industries, Ltd.) 52.5wt%
Tripropylene glycol diacrylate
(Aronix M-220, manufactured by Toa Gosei Co., Ltd.) 25wt%
Glycerin EO adduct triacrylate
(NK ester A-Gly-3E manufactured by Shin-Nakamura Chemical Co., Ltd.) 10wt%
Irgacure 819 (Ciba Specialty Chemicals Co., Ltd.) 1.5wt%
Irgacure 369 (Ciba Specialty Chemicals Co., Ltd.) 3.5wt%
Darocur EHA (Ciba Specialty Chemicals Co., Ltd.) 1.0wt%
KEMISORB 1001 (Chemipro Kasei Co., Ltd., UV absorber) 0.5wt%
Polymerizable fine particle 1 6.0 wt%

Production Method of Transparent Ink Composition 3 In a light-shielding container, 20 parts by weight of monomer solution B, 38.5 parts by weight of beam set 770, 25 parts by weight of Aronics M-220, 10 parts by weight of NK ester A-Gly-3E, Irgacure 819 1.5 parts by weight, Irgacure 369 3.5 parts by weight, Darocur EHA 1 part by weight, KEMISORB 1001 0.5 part by weight were added and stirred with a magnetic stirrer for 1 hour to prepare a transparent ink composition 3. .

(Transparent ink composition 4 (T4))
N-vinylformamide
(Beam Set 770 Arakawa Chemical Industries, Ltd.) 52.0wt%
Tripropylene glycol diacrylate
(Aronix M-220, manufactured by Toa Gosei Co., Ltd.) 25wt%
Glycerin EO adduct triacrylate
(NK ester A-Gly-3E manufactured by Shin-Nakamura Chemical Co., Ltd.) 10wt%
Irgacure 819 (Ciba Specialty Chemicals Co., Ltd.) 1.5wt%
Irgacure 369 (Ciba Specialty Chemicals Co., Ltd.) 3.5wt%
Darocur EHA (Ciba Specialty Chemicals Co., Ltd.) 1.0wt%
KEMISORB 1001 (manufactured by Chemipro Kasei Co., Ltd., UV absorber) 1.0 wt%
Polymerizable fine particle 1 6.0 wt%

Production Method of Transparent Ink Composition 4 In a light-shielding container, 20 parts by weight of monomer solution B, 38 parts by weight of beam set 770, 25 parts by weight of Aronix M-220, 10 parts by weight of NK ester A-Gly-3E, Irgacure 819 1 0.5 parts by weight, 3.5 parts by weight of Irgacure 369, 1 part by weight of Darocur EHA and 1.0 part by weight of KEMISORB 1001 were added and stirred and mixed with a magnetic stirrer for 1 hour to prepare a transparent ink composition 4.

(Transparent ink composition 5 (T5))
N-vinylformamide
(Beam Set 770 Arakawa Chemical Industries, Ltd.) 52.0wt%
Tripropylene glycol diacrylate
(Aronix M-220, manufactured by Toa Gosei Co., Ltd.) 25wt%
Glycerin EO adduct triacrylate
(NK ester A-Gly-3E manufactured by Shin-Nakamura Chemical Co., Ltd.) 10wt%
Irgacure 819 (Ciba Specialty Chemicals Co., Ltd.) 1.5wt%
Irgacure 369 (Ciba Specialty Chemicals Co., Ltd.) 3.5wt%
Darocur EHA (Ciba Specialty Chemicals Co., Ltd.) 1.0wt%
Irganox 1076
(Antioxidant manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0wt%
Polymerizable fine particle 1 6.0 wt%

Production Method of Transparent Ink Composition 5 In a light-shielding container, 20 parts by weight of OLE_LINK1 monomer solution B, 38 parts by weight of OLE_LINK1 beam set 770, 25 parts by weight of Aronix M-220, 10 parts by weight of NK ester A-Gly-3E, Irgacure A transparent ink composition 5 was prepared by adding 1.5 parts by weight of 819, 3.5 parts by weight of Irgacure 369, 1 part by weight of Darocur EHA, 1.0 part by weight of Irganox 1076, and stirring and mixing with a magnetic stirrer for 1 hour. .

(Transparent ink composition 6 (T6))
N-vinylformamide
(Beam Set 770 Arakawa Chemical Industries, Ltd.) 51.0 wt%
Tripropylene glycol diacrylate
(Aronix M-220, manufactured by Toa Gosei Co., Ltd.) 25wt%
Glycerin EO adduct triacrylate
(NK ester A-Gly-3E manufactured by Shin-Nakamura Chemical Co., Ltd.) 10wt%
Irgacure 819 (Ciba Specialty Chemicals Co., Ltd.) 1.5wt%
Irgacure 369 (Ciba Specialty Chemicals Co., Ltd.) 3.5wt%
Darocur EHA (Ciba Specialty Chemicals Co., Ltd.) 1.0wt%
KEMISORB 1001 (Kemipro Kasei Co., Ltd., UV absorber) 1.0 wt%
Irganox 1076
(Antioxidant manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.0wt%
Polymerizable fine particle 1 6.0 wt%

Production Method of Transparent Ink Composition 6 Into a light-shielding container, 20 parts by weight of monomer solution B, 37 parts by weight of beam set 770, 25 parts by weight of Aronics M-220, 10 parts by weight of NK ester A-Gly-3E, Irgacure 819 1 .5 parts by weight, Irgacure 369 3.5 parts by weight, Darocur EHA 1 part by weight, KEMISORB 1001 1.0 part by weight, Irganox 1076 1.0 part by weight, and stirring and mixing with a magnetic stirrer for 1 hour, transparent ink Composition 6 was prepared.

About the trade name of OLE_LINK2 compound ・ Irgacure 819 (Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide)
Irgacure 369 (2-benzyl-2-dimethylamine-1- (4-morpholinophenyl) -butanone-1)
Darocur EHA (2-ethylhexyl-4-dimethylaminobenzoate)
OLE_LINK2

4). Evaluation Method (1) Curability Test of Transparent Ink Composition (Ink Composition B) Transparent ink compositions 1 to 6 were dropped in a glass plate shape at 365 nm by an ultraviolet irradiation device using an ultraviolet LED as an irradiation light source. Printing and curing were performed under curing conditions such that the integrated light amount was 110 mJ / cm ² . The curability in this case was visually evaluated by appearance.

As the ultraviolet irradiation device, the following was used.
Light source UV LED UCCU033 (manufactured by Nichia Corporation),
Output 100mW, peak wavelength 365nm
Irradiation condition 22 mW / cm ² , integrated light quantity 110 mJ / cm ²

Curability evaluation indexes are as follows.
○: Completely cured.
Δ: There is an uncured portion on the surface or inside.
X: Only a part is cured.

  The evaluation results are shown in Table 1 below.

(2) Light resistance test Using an ink jet printer PM-G900 manufactured by Seiko Epson Corporation, ink compositions A and B shown in Table 2 below are filled in separate nozzle rows, and discharged under normal temperature and normal pressure. Pattern printing was performed. As the recording medium, photographic paper <silk texture> (manufactured by Seiko Epson Corporation, model number KA420MSH) was used. Then, printing and curing are performed under curing conditions such that the integrated light quantity at 365 nm is 110 mJ / cm ² using an ultraviolet irradiation device (used for the above-described curing test) installed at the paper discharge port, and then light resistance evaluation is performed. Went.
Light irradiation in the light resistance test is performed using a xenon weatherometer Ci-5000 (manufactured by ATLAS), illuminance 105 W / G (300 to 400 dyn / cm = about 150,000 Lux), temperature 24 ° C., humidity 60% RH. Under these conditions, an air layer and a 2 mm thick soda lime glass were placed on the sample.
O.D. before light irradiation, 400 hours after light irradiation and 600 hours after light irradiation. D. Each value (optical density) was measured using a spectrophotometer GRETAG SPM100 (manufactured by GRETAG), and the relative O.D. D. The value is shown.
Relative O.D. D. Value = O. D. Value / initial O.D. D. Value This relative O.D. D. The higher the value (closer to 1), the higher the light resistance.
The evaluation results are shown in Table 2 below.

1a recording head, 1b recording head, 2a ink tank, 2b ink tank, 3 tube, 4 carriage, 5 motor, 6 timing belt, 7 recording medium, 8 platen, 9 guide, 10 cap, 11 suction pump, 12 tube, 13 Waste ink tank, 14 heater, 15 UV irradiation means

Claims (3)

  An ink composition A containing at least a colorant, an ultraviolet absorber and an antioxidant, and an ink composition B containing at least a photopolymerization initiator, a polymerizable compound and a polymerization accelerator are adhered to the recording medium. And then printing by irradiating with ultraviolet rays.   The ink jet recording method according to claim 1, wherein the color material is a pigment.   2. The ink jet recording method according to claim 1, wherein the polymerization accelerator is a fine particle having a polymerizable functional group.

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