JP2007112970A - Ink set curable with ultraviolet ray and method of recording image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-liquid mixing curing type ink set curable with ultraviolet rays, which is free from polymerization inhibition derived from surrounded environmental oxygen, moisture, impurities, etc., and has excellent storage stability; and to provide a method of recording an image. <P>SOLUTION: The ink set curable with ultraviolet rays, comprises an ink composition A containing at least a cationically polymerizable compound and a radical photopolymerization initiator, and an ink composition B containing at least a radically polymerizable compound and a photoacid generator. Either of the compositions suitably contains a colorant. A plurality of compositions may contain colorants. The method of recording an image using the ink set, is carried out by the followings: adhering the compositions A and B onto the same position of a recording medium, followed by curing them through ultraviolet exposure; or adhering a mixture of the compositions A and B onto the recording medium, followed by curing it through ultraviolet exposure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultraviolet curable ink set and an image recording method using the ink set, and in particular, there is no polymerization inhibition derived from the surrounding environment such as oxygen, moisture, impurities, etc., and excellent storage stability. The present invention relates to a liquid mixture curable ultraviolet curable ink set and an image recording method.

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 coloring material to the recording medium.

  In response to such a requirement, an ultraviolet curable inkjet ink containing a coloring material, an ultraviolet curing agent (radical polymerizable compound), a (photo radical) 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. In radical photopolymerization reaction, there are advantages such as wide selection of polymerization initiator, monomer, prepolymer, etc., high degree of freedom in ink composition, and less inhibition of curing due to impurities, moisture in surrounding environment, etc. . On the other hand, however, there is a problem that polymerization is inhibited by oxygen and the cure shrinkage is high.

On the other hand, an active energy ray-curable inkjet ink composition using a cationic polymerizable compound and a cationic polymerization initiator has been proposed for the above problems (see, for example, Patent Document 2).
The active energy ray-curable inkjet ink composition using a cationic polymerizable compound and a cationic polymerization initiator has no polymerization inhibition by oxygen, and the polymerization reaction proceeds even after the light irradiation is completed, so that unreacted monomers can be reduced. Furthermore, the ink composition itself can have a low viscosity. On the other hand, however, there are problems in that there are few choices of materials, the composition is restricted, and curing inhibition is caused by ionic impurities and moisture.

US Pat. No. 5,562,001 JP 2001-220526 A

In addition, both radical polymerization reaction composition and cationic polymerization reaction composition are inferior in storage stability, and have a drawback that they cannot be used due to increase in viscosity, gelation, etc. after storage at room temperature and several months. there were.
The present invention overcomes the drawbacks of the above-mentioned conventional techniques, does not inhibit polymerization originating from the surrounding environment such as oxygen, moisture, impurities, etc., and has an excellent storage stability and a monomer-initiator separation type UV curable ink set. And an image recording method.

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 ultraviolet curable ink set comprising an ink composition A containing at least a cationic polymerizable compound and a radical photopolymerization initiator, and an ink composition B containing at least a radical polymerizable compound and a photoacid generator.
(2) The ultraviolet curable ink set according to (1), wherein the cationically polymerizable compound is a compound having a cyclic ether in the molecular structure.
(3) The ultraviolet curable ink set of (1), wherein the radical polymerizable compound is a compound having an unsaturated double bond in the molecular structure.

(4) The ultraviolet curable ink set according to (1), wherein the ink composition A contains a monofunctional radically polymerizable compound.
(5) The ultraviolet curable ink set of (4), wherein the monofunctional radically polymerizable compound is N-vinylformamide.
(6) The ultraviolet curable ink set according to claim 1, wherein at least one of ink composition A and ink composition B contains polymerizable fine particles.
(7) The ultraviolet curable ink set according to (1), wherein a color material is contained in either one of the ink composition A or the ink composition B.
(8) The ultraviolet curable ink set according to (7), comprising a plurality of ink compositions containing a color material, and comprising seeds.

(9) An image recording method using the ultraviolet curable ink set of (1).
(10) The image recording method according to (9), wherein the ink composition A and the ink composition B are attached to the same position on the recording medium and exposed to ultraviolet rays.
(11) The image recording method according to (9), wherein the ink composition A and the ink composition B are mixed, adhered onto a recording medium, and exposed to ultraviolet rays.

In order to solve the problem of storage stability, a method is known in which constituent components of an ink composition are divided into a multi-component ink composition. By separating and storing the polymerizable compound and the photopolymerization initiator, storage stability can be improved, but the problem of curing inhibition derived from the surrounding environment (oxygen, moisture, impurities, etc.) is not solved. .
The ultraviolet curable ink set of the present invention comprises an ink composition A containing at least a cationic polymerizable compound and a radical photopolymerization initiator, and an ink composition B containing at least a radical polymerizable compound and a photoacid generator. By being of a separation type, the constituent components of radical polymerization and cationic polymerization are divided to form an ink composition in which each polymerizable compound and photopolymerization initiator (photopolymerization catalyst) are separated, and further, photoradical polymerization and light A novel image recording method using a method in which cationic polymerization is performed simultaneously (hybrid polymerization) can be employed. Therefore, there is no polymerization inhibition derived from the surrounding environment such as oxygen, moisture and impurities, no significant increase in viscosity or gelation is observed even after storage for 1 year at room temperature, and there is no particular problem in storage stability during use. It is also excellent.

Hereinafter, the ultraviolet curable ink set of the present invention will be described in detail.
The ultraviolet curable ink set of the present invention comprises an ink composition A containing at least a cationic polymerizable compound and a radical photopolymerization initiator, and an ink composition B containing at least a radical polymerizable compound and a photoacid generator. .

The ink composition A used in the ultraviolet curable ink set of the present invention will be described.
Although it does not specifically limit as a cationically polymerizable compound used for the ink composition A of this invention, A vinyl ether compound, an oxetane compound, a (alicyclic) epoxy compound, a glycidyl compound, a cyclic ether compound, etc. are mentioned.
Preferable cationically polymerizable compounds are cyclic ethers that undergo ring-opening polymerization by the action of a cation, and more preferable are alicyclic epoxy compounds and oxetane compounds. Furthermore, since it is excellent in sclerosis | hardenability, it is especially preferable to mix and use an alicyclic epoxy compound and an oxetane compound. In this case, the mixing ratio of the alicyclic epoxy compound and the oxetane compound (alicyclic epoxy compound: oxetane compound) is usually 5:95 to 95: 5, preferably 10:90 to 50:50, as a mass ratio. Is done. If the amount of oxetane is too small, the cured product tends to bend and the solvent resistance is lowered. On the other hand, if the amount of oxetane is too large, the risk of poor curing in a humid environment increases.

  Preferred oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 1,4bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3- (phenoxymethyl) oxetane, 3 Oxetanes such as -ethyl-3- (2-ethylhexyloxymethyl) oxetane and di [1-ethyl (3-oxetanyl)] methyl ether.

  Preferred alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate (commercially available products under the trade names Cyracure UVR6105, UVR6110 and CELLOXIDE2021), bis (3,4-epoxycyclohexyl). Methyl) adipate (commercial product name is UVR6128), vinylcyclohexene monoepoxide (commercial product name is CELOXIDE 2000), ε-caprolactone modified 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarboxylate (commercial product) 1-methyl-4- (2-methyloxiranyl) -7-oxabicyclo [4,1,0] heptane (trade name CELOXI) And an alicyclic epoxy resin such as DE3000 (commercially available). Commercial products having trade names of UVR 6105, UVR 6110, and UVR 6128 are all available from Dow Chemical Company. Commercial products having the trade names of CELOXIDE 2000, CELLOXIDE 2021, CELOXIDE 2081 and CELOXIDE 3000 are all available from Daicel Chemical Industries, Ltd. UVR 6105 is a low viscosity product of UVR 6110.

The synthesis of the alicyclic epoxy compound can be performed according to the method described in the following patent.
U.S. Pat. No. 2,745,847, U.S. Pat. No. 2,750,395, U.S. Pat. No. 2,853,498, U.S. Pat. No. 2,853,499 and U.S. Pat. No. 2,863,881.

  Specific examples of the cationically polymerizable compound are described in more detail in JP-A-8-143806, JP-A-8-283320, JP-A-2000-186079, JP-A-2000-327672, and the like. The present invention can also be carried out by appropriately selecting from the compounds exemplified therein.

  The radical photopolymerization initiator used in the ink composition A is not particularly limited. For example, benzophenone, acetophenone, α-aminoketone, α-hydroxyketone, monoacylphosphine oxide, bisacylphosphine oxide, thioxanthone, An oxime type thing etc. are mentioned.

  Also, Vice 10, 30 (manufactured by Stauffer Chemical), Irgacure 127, 184, 500, 651, 2959, 907, 369, 379, 754, 1700, 1800, 1850, 819, OXE01, Darocur 1173, TPO, ITX (Ciba A photopolymerization initiator available under the trade names of Specialty Chemicals, Quantacure CTX (Aceto Chemical), and ESACURE KIP150 (Lamberti) can also be used.

  Further, the ink composition A of the ultraviolet curable ink set of the present invention may contain a monofunctional radically polymerizable compound (monomer). If it is a monofunctional radically polymerizable monomer, it is less likely to react with the radical photopolymerization initiator during storage to cause unwanted polymerization. As the monofunctional radically polymerizable monomer used here, N-vinylformamide, allyl glycol and the like are suitable.

Although it does not specifically limit as a radically polymerizable compound used for the ink composition B of the ultraviolet curable ink set of this invention, For example, a monomer is mentioned.
A monomer refers to a molecule that can be a structural unit of the basic structure of a polymer. Moreover, as a monomer used in this invention, there are a monofunctional monomer, a bifunctional monomer, and a polyfunctional monomer, and any of them can be used. Any monomer preferably has a PII value (Primary Irritation Index, primary skin irritation) of 2 or less.

  Examples of monofunctional monomers, bifunctional monomers, and polyfunctional monomers having a PII value of 2 or less that can be used in the ink composition B of the present invention are shown in Table 1 below.

  In addition, the viscosity in the said table | surface is a measured value in 25 degreeC.

  Preferred radical polymerizable compounds are N-vinylformamide, isobornyl acrylate, phenoxyethyl acrylate or acryloyl morpholine which are monofunctional monomers.

  Moreover, as a radically polymerizable compound of this invention, the oligomer other than the above-mentioned monomer may be contained.

Although it does not specifically limit as a photo-acid generator used for the ink composition B of the ultraviolet curable ink set of this invention, A diazo sulfone type, a triphenyl sulfonium type, a diphenyl iodonium type, a titanocene type compound, camphor quinone, etc. are mentioned. It is done.
Preferred photoacid generators are diazosulfone, triphenylsulfonium, and diphenyliodonium compounds, with triphenylsulfonium being particularly preferred, and specifically, Cyracure UVI6692 (manufactured by Dow Chemical Co.).

The ink composition A or B of the present invention may contain a polymerization accelerator.
The polymerization accelerator is not particularly limited, and examples thereof include Darocur EHA, EDB (manufactured by Ciba Specialty Chemicals), and fine particles having a polymerizable functional group (hereinafter also referred to as polymerizable fine particles). Although the mechanism of action of the polymerizable fine particles is not clear, the monomer component is adsorbed on the surface of the fine particles by being contained in the ink composition, and the monomer adsorbed on the surface of the fine particles is a polymerization initiator. It is presumed that the radicals generated by the above will not escape, and thus contribute to the polymerization efficiently.
The fine particle portion having a polymerizable functional group is not particularly limited, but is generally referred to as an extender pigment, and examples thereof include inorganic compounds such as silica, alumina, titania, calcium oxide, and in particular, silica, alumina, etc. 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 it is also possible to use 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 a silane-based fine particle having a large number of hydroxyl groups and the like is prepared by a sol-gel reaction of a silane compound such as silanol, and the polymerizable functional group is imparted to the hydroxyl group. The method of making it react with such a compound is mentioned.
The content of the polymerizable fine particles in the ink composition A or B of the present invention is not particularly limited, and should be appropriately selected according to the use form, conditions, the relationship between the viscosity of the ink composition and the polymerizable property, and the like. However, it is preferably 10% by mass or less based on the total amount of the ink composition.

  Further, the ink composition A or B containing a radical polymerizable compound preferably contains a thermal radical polymerization inhibitor. Thereby, the storage stability of the ink compositions A and B is improved. Examples of the thermal radical polymerization inhibitor include Irgastab UV-10 (manufactured by Ciba Specialty Chemicals).

In addition, the ultraviolet curable ink set of the present invention may contain a color material in either one of the ink composition A or the ink composition B.
The coloring material used in this case 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.

  Specific examples of the pigment include carbon black, No. manufactured by Mitsubishi Chemical Corporation. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B, etc. are Raven 5750, 5250, 5000, 3500, 1255, 700, etc. made by Columbia, and Regal 400R, 330R, 660R, Mogu L, 700, Monarch 800, 880, made by Cabot, 900, 1000, 1100, 1300, 1400, etc. are Color Black FW1, FW2, FW2V, FW18, FW200, ColorBlack S150, S160, S170, Printex 35, U, the same V, the same 140 U, the Special Black 6, the same 5, the same 4 A, the same 4, and the like.

Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 180, 185, 213 and the like.
Examples of pigments used for magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, 209, C.I. I. Pigment violet 19 and the like.

Further, examples of pigments used for cyan ink include C.I. I. And CI Pigment Blue 1, 2, 3, 15: 3, 15: 4, 60, 16, and 22.
According to a preferred embodiment of the present invention, the pigment preferably has an average particle size in the range of 10 to 200 nm, more preferably about 50 to 150 nm.
The addition amount of the coloring material in the ink composition 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.

  According to a preferred embodiment of the present invention, these pigments can be used as the ink composition A or B 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.

  When the ink composition contains a color material, the ink composition containing the color material may be composed of a plurality of types for each color. For example, in addition to the basic four colors of yellow, magenta, cyan, and black, when adding the same series of dark and light colors for each color, in addition to light magenta, dark red, and cyan, in addition to magenta In addition to light light cyan, dark blue, and black, light gray, light black, and dark matte black can be used.

In addition, the ink composition A or B of the present invention includes a wetting agent, a penetrating solvent, a pH adjusting agent, a preservative, a fungicide, etc. as other publicly known components that can be used in an ultraviolet curable ink. You may do it.
In addition, sensitizers, surfactants, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins as necessary Waxes can be added.
It is also possible to add a very small amount of an organic solvent in order to improve the adhesion with the recording medium. In this case, it is effective to add in a range that does not cause the problem of solvent resistance and VOC, and the amount is 5% or less, preferably 3% or less. However, the ink composition A or B of the present invention is more preferably solventless.

  The ultraviolet curable ink set of the present invention performs a curing reaction by irradiating light after mixing the ink compositions A and B. As long as mixing is performed before the curing reaction, it may be performed before or after printing. That is, the mixing and printing may be in a form in which the ink composition A and the ink composition B are attached to the same position on the recording medium. It may be in the form of adhering to.

  In addition, when the ultraviolet curable ink set of the present invention is used in an ink jet recording method, it is preferable that the ink compositions A and B each have a viscosity of 10 mPa · s or less at 25 ° C.

In the ink jet recording method using the ultraviolet curable ink set of the present invention, the ink compositions A and B are mixed on the recording medium and then ejected, or the ink compositions A and B are ejected at the same time. Either the composition A or B is ejected first, the other ink composition is ejected immediately thereafter, and then ultraviolet rays are irradiated.
The irradiation light source is not particularly limited, but the irradiation light source is preferably light having a wavelength of 350 nm or more and 450 nm or less.
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 using the ultraviolet curable ink set of the present invention, heating may be performed before, at the same time as, or after irradiation with ultraviolet light. Heating is performed by bringing a heat source into contact with the recording medium, irradiating far infrared rays, near infrared rays, microwaves (electromagnetic waves having a maximum wavelength of about 2,450 MHz), etc., or blowing hot air to the recording medium. The method of heating without mentioning is mentioned.

Further, an example of a recording apparatus that performs an ink jet recording method using the ultraviolet curable ink set of 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 tank 1a (and 1b) connected to the ink tank 2a having the ink composition A and the ink tank 2b having the ink composition B by the tube 3 is driven by the timing belt 6 driven by the motor 5 along the carriage 4. Move in the direction of arrow A. 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.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
[Preparation of Ink Compositions 1-2]
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 7.9 parts by weight of Compound Silaace S710 (manufactured by Chisso Corporation) was added. While stirring with a magnetic stirrer, 4 parts by weight of 0.05 mol / liter 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 Monomer Dispersion B To a 1000 ml round bottom flask, 70 parts by weight of N-vinylformamide (hereinafter abbreviated as NVF) and 100 parts by weight of the above dispersion A were added, and IPA was distilled off using a rotary evaporator to polymerize. Monomer solution B containing 30 wt% of conductive fine particles 1 was obtained.

An ink composition having the following composition was prepared. The preparation was performed as follows. 15 parts of pigment, 1.0 part of dispersant, and 84 parts of NVF were mixed and stirred to form a mixture, which was dispersed for 6 hours with zirconia beads (diameter 1.5 mm) using a sand mill (manufactured by Yaskawa Seisakusho). Thereafter, zirconia beads were separated with a separator to obtain a pigment dispersion C.
Next, monomers other than the pigment and dispersant, the monomer solution B, and various additives in the following blending components are mixed and completely dissolved to prepare an ink solvent, and then the pigment dispersion C is stirred in the ink solvent. After the dropwise addition, the mixture was stirred for 30 minutes at room temperature. Thereafter, the resultant was filtered through a 5 μm membrane filter to obtain ink composition 1.
Separately, the monomers, monomer solution B and various additives were mixed and completely dissolved, and mixed and stirred for 30 minutes. Thereafter, the mixture was filtered through a 5 μm membrane filter to obtain ink composition 2.

[Ink composition 1]
C. I. Pigment Yellow 155 (pigment): 3.0% by weight (hereinafter, wt%)
Polyoxyalkylene-added polyalkyleneamine (dispersing agent, DISCOL N-518 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1.0 wt%
NVF (Arakawa Chemical Industries): 23.0wt%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (manufactured by Toagosei Co., Ltd.): 54.3 wt%
Cyracure UVR-6105 (Dow Chemical Co.): 10.0wt%
Irgacure 819
(Ciba Specialty Chemicals): 4.0wt%
Irgacure 127
(Ciba Specialty Chemicals): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Ink composition 2]
NVF (Arakawa Chemical Industries): 24.0 wt%
Lauryl methacrylate (Mitsubishi Gas Chemical Co., Ltd.): 21.3 wt%
Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toagosei Co., Ltd.): 25.0 wt%
Trimethylolpropane EO-modified triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat # 360): 20.0 wt%
Cyracure UVI-6692 (manufactured by Dow Chemical Co.): 5.0 wt%
Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd., sensitizer): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Print test 1]
Using the ink-jet printer PM-G900 manufactured by Seiko Epson Corporation, the ink compositions 1 and 2 of the above example are filled in different nozzle rows, and each ink droplet is simultaneously landed at the same position under normal temperature and normal pressure. The solid pattern was printed under the conditions to be used. OHP film of the recording medium of A4 size (manufactured by Fuji Xerox Co., Ltd., was used XEROX FILM <without frame>. And placed on the sheet discharge outlet, an ultraviolet irradiation light source, the integrated amount of light at 365nm within 400 mJ / cm ² Printing and curing were performed under such curing conditions, and it was confirmed that a yellow cured coating film was obtained.

[Preparation of ink compositions 3 to 4]
Ink compositions 3 to 4 having the following compositions were prepared in the same manner as ink compositions 1 and 2.
[Ink composition 3]
NVF (Arakawa Chemical Industries): 23.0wt%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (manufactured by Toagosei Co., Ltd.): 57.3 wt%
Cyracure UVR-6105 (Dow Chemical Co.): 10.0wt%
Irgacure 819
(Ciba Specialty Chemicals): 4.0wt%
Irgacure 127
(Ciba Specialty Chemicals): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Ink composition 4]
C. I. Pigment Yellow 155 (pigment): 3.0 wt%
Polyoxyalkylene-added polyalkyleneamine (dispersing agent, DISCOL N-518 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1.0 wt%
NVF (Arakawa Chemical Industries): 24.0 wt%
Lauryl methacrylate (Mitsubishi Gas Chemical Co., Ltd.): 27.3 wt%
Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toagosei Co., Ltd.): 20.0 wt%
Trimethylolpropane EO-modified triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat # 360): 20.0 wt%
Cyracure UVI-6692 (manufactured by Dow Chemical Co.): 5.0 wt%
Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd., sensitizer): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Print test 2]
Using the ink-jet printer PM-G900 manufactured by Seiko Epson Corporation, the ink compositions 3 and 4 of the above example are filled in different nozzle arrays, and each ink droplet is simultaneously landed at the same position under normal temperature and normal pressure. The solid pattern was printed under the conditions to be used. OHP film of the recording medium of A4 size (manufactured by Fuji Xerox Co., Ltd., was used XEROX FILM <without frame>. And placed on the sheet discharge outlet, an ultraviolet irradiation light source, the integrated amount of light at 365nm within 400 mJ / cm ² Printing and curing were performed under such curing conditions, and it was confirmed that a yellow cured coating film was obtained.

[Preparation of ink compositions 5 to 7]
Ink compositions 5 to 7 having the following compositions were prepared in the same manner as ink composition 1.

[Ink composition 5]
C. I. Pigment Violet 19 (pigment): 3.0 wt%
Polyoxyalkylene-added polyalkyleneamine (dispersing agent, DISCOL N-518 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1.0 wt%
NVF (Arakawa Chemical Industries): 23.0wt%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (manufactured by Toagosei Co., Ltd.): 54.3 wt%
Cyracure UVR-6105 (Dow Chemical Co.): 10.0wt%
Irgacure 819
(Ciba Specialty Chemicals): 4.0wt%
Irgacure 127
(Ciba Specialty Chemicals): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Ink composition 6]
C. I. Pigment Blue 15: 3 (pigment): 3.0 wt%
Polyoxyalkylene-added polyalkyleneamine (dispersing agent, DISCOL N-518 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1.0 wt%
NVF (Arakawa Chemical Industries): 23.0wt%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (manufactured by Toagosei Co., Ltd.): 54.3 wt%
Cyracure UVR-6105 (Dow Chemical Co.): 10.0wt%
Irgacure 819
(Ciba Specialty Chemicals): 4.0wt%
Irgacure 127
(Ciba Specialty Chemicals): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Ink composition 7]
C. I. Pigment Black 7 (pigment): 3.0 wt%
Polyoxyalkylene-added polyalkyleneamine (dispersing agent, DISCOL N-518 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1.0 wt%
NVF (Arakawa Chemical Industries): 23.0wt%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (manufactured by Toagosei Co., Ltd.): 53.3 wt%
Cyracure UVR-6105 (Dow Chemical Co.): 10.0wt%
Irgacure 819
(Ciba Specialty Chemicals): 4.0wt%
Irgacure 127
(Ciba Specialty Chemicals): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Print test 3]
Using an ink-jet printer PM-G900 manufactured by Seiko Epson Corporation, each of the ink compositions 1 and 5 to 7 in the above example is filled in the corresponding color row and the ink composition 2 is filled in the gloss optimizer row. A full color image was printed under printing conditions such that each color ink drop corresponds to a position under normal pressure and the ink composition 2 covers the entire image area. An A4-sized OHP film (manufactured by Fuji Xerox Co., Ltd., XEROX FILM <no frame>) was used as the recording medium. Then, it is confirmed that a cured coating film of a full-color image can be obtained by performing printing and curing processing with a UV irradiation light source installed at the paper discharge port under curing conditions such that the integrated light quantity at 365 nm to 420 nm is 420 mJ / cm ^2. did.

[Storage stability]
[Preparation of ink compositions 8 to 9]
Ink compositions 8 to 9 having the following compositions were prepared according to the method for preparing ink compositions 1 to 7.

[Ink composition 8]
C. I. Pigment Yellow 155 (pigment): 3.0 wt%
Polyoxyalkylene-added polyalkyleneamine (dispersing agent, DISCOL N-518 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1.0 wt%
NVF (Arakawa Chemical Industries): 23.0wt%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (manufactured by Toagosei Co., Ltd.): 54.3 wt%
Cyracure UVR-6105 (Dow Chemical Co.): 10.0wt%
Cyracure UVI-6692 (manufactured by Dow Chemical Co.): 5.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

[Ink composition 9]
NVF (Arakawa Chemical Industries): 24.0 wt%
Lauryl methacrylate (Mitsubishi Gas Chemical Co., Ltd.): 21.3 wt%
Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toagosei Co., Ltd.): 25.0 wt%
Trimethylolpropane EO-modified triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat # 360): 20.0 wt%
Irgacure 819
(Ciba Specialty Chemicals): 4.0wt%
Irgacure 127
(Ciba Specialty Chemicals): 1.0 wt%
Kayacure DETX-S (Nippon Kayaku Co., Ltd.): 1.0 wt%
BYK-UV3570 (manufactured by Big Chemie Japan, polyester-modified silicone surfactant): 0.5 wt%
Irgastab UV10
(Ciba Specialty Chemicals): 0.2wt%
Polymerizable fine particles 1: 3.0 wt%

  Ink compositions 8 and 9 were gelled and solidified in about one week and could no longer be used. However, ink compositions 1 to 7 of the present invention did not show a significant change in viscosity even after one month had passed. It was possible to use it.

It is a figure which shows the inkjet recording device preferably used for implementation of the inkjet recording method using the ultraviolet curable ink of this invention.

Explanation of symbols

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 (11)

  An ultraviolet curable ink set comprising an ink composition A containing at least a cationic polymerizable compound and a radical photopolymerization initiator, and an ink composition B containing at least a radical polymerizable compound and a photoacid generator.   The ultraviolet curable ink set according to claim 1, wherein the cationically polymerizable compound is a compound having a cyclic ether in a molecular structure.   2. The ultraviolet curable ink set according to claim 1, wherein the radical polymerizable compound is a compound having an unsaturated double bond in the molecular structure.   The ultraviolet curable ink set according to claim 1, wherein the ink composition A contains a monofunctional radically polymerizable compound.   The ultraviolet curable ink set according to claim 4, wherein the monofunctional radically polymerizable compound is N-vinylformamide.   The ultraviolet curable ink set according to claim 1, wherein at least one of the ink composition A and the ink composition B contains polymerizable fine particles.   The ultraviolet curable ink set according to claim 1, wherein either one of the ink composition A or the ink composition B contains a color material.   The ultraviolet curable ink set according to claim 7, comprising a plurality of ink compositions containing a color material.   An image recording method using the ultraviolet curable ink set according to claim 1.   The image recording method according to claim 9, wherein the ink composition A and the ink composition B are attached to the same position on the recording medium and exposed to ultraviolet rays.   The image recording method according to claim 9, wherein the ink composition A and the ink composition B are mixed, adhered onto a recording medium, and exposed to ultraviolet light.

Images