JP2007237405A - Ink-jet recording ink set and ink-jet image recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet recording ink set, with which a high image quality image having a long term storage stability and being curable even with a low exposure energy can be formed, and an ink-jet image recording method, in which the ink set is employed. <P>SOLUTION: This ink-jet recording ink set comprises a plurality of kinds of liquids including at least a first liquid and a second liquid having compositions different from each other, wherein the first liquid includes at least one kind of cleavage type polymerization initiators, the second liquid includes a hydrogen abstraction type polymerization initiator and at least one kind of sensitizers and at least one among a plurality of kinds of the liquids includes a polymerizable compound. Further, in order to form an image, the first liquid and the second liquid are simultaneously given on a medium to be recorded or either one of the liquids is given first and then the remaining one is given so as to bring both the liquids into contact with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink set for ink jet recording and an ink jet image recording method, and more particularly, to an ink set for ink jet recording capable of forming a high quality image and an ink set for ink jet recording of a multi-liquid aggregation type. The present invention relates to a method for recording an inkjet image.

  An ink jet system that discharges ink from an ink discharge port such as a nozzle is small and inexpensive, and is used in many printers because it can form an image without contact with a print medium. Among these ink jet systems, the piezoelectric ink jet system that ejects ink using deformation of piezoelectric elements and the thermal ink jet system that ejects ink using the boiling phenomenon of ink due to thermal energy are excellent in high resolution and high speed printability. Has characteristics.

Currently, high speed and high image quality are important issues when printing on non-water-absorbing recording media such as plain paper or plastic with an ink jet printer. In particular, if it takes a long time to dry the droplets after printing, image bleeding tends to occur, and droplet ejection interference occurs due to mixing between adjacent ink droplets, which not only prevents sharp image formation. In the case of using a non-water-absorbing recording medium, there is a practical problem such that the drying of the solvent is extremely slow and it is necessary to dry without overlapping the recorded material immediately after printing. The droplet ejection interference is a phenomenon in which droplets ejected adjacent to each other are united to reduce the surface energy (to reduce the surface area). Since the movement of the droplets occurs when adjacent droplets coalesce, they deviate from the landing position, especially when drawing thin lines with ink containing colorant, the line width is non-uniform and the surface is drawn If it does, it will appear uneven.
As one of the methods for accelerating ink curing in order to suppress image bleeding and droplet ejection interference, an inkjet ink that is cured and fixed by radiation rather than volatilization of the ink solvent has been proposed (for example, Patent Document 1). reference.). However, since the pigment dispersion is used as the coloring component, the nozzles are clogged due to the aggregation of the pigment, and it is difficult to discharge the ink stably.
For this reason, in order to perform image formation excellent in transparency and color tone without using a pigment, an ultraviolet curable ink using a dye as a colorant is also disclosed (for example, see Patent Document 2). This ink has a problem that an undesirable polymerization reaction easily occurs during storage and storage stability is not sufficient. Furthermore, since conductive salts are contained and the solubility in these inks may be poor, there is a concern of poor printing due to precipitation in a long-term storage state.

  For the purpose of coexistence of storage stability and high-speed drying properties, a technique for reacting both on a recording medium using a two-component ink is proposed, for example, after attaching a liquid having a basic polymer, A method of recording an ink containing an anionic dye (for example, see Patent Document 3), a method of applying an ink containing an anionic compound and a colorant after applying a liquid composition containing a cationic substance (for example, Patent Document 4), and a recording method (for example, see Patent Document 5) using an ink containing a photocurable resin on one side and a photopolymerization initiator on the other side is disclosed. However, these methods are intended to suppress blurring of the image by precipitation of the dye itself, and cannot suppress droplet ejection interference, and since the aqueous solvent is included, the drying speed is low. Further, the deposited dye tends to be unevenly distributed on the recording medium, and there is a concern that the image quality is deteriorated.

Also, actinic ray curable ink that uses actinic ray curable ink, has excellent character quality, has no color mixing, and stably records high-definition images with no coloring material. Disclosed is an image forming method characterized in that an actinic ray curable ink containing less than 1% of a mold ink or a color material is first ejected onto a recording material, and then an actinic ray curable ink containing a color material is ejected. (For example, refer to Patent Document 6). However, the actinic ray curable ink and the image forming method using the same disclosed in the same document require a lot of energy to cure the ink. Therefore, particularly when a light emitting diode or the like is used as an exposure light source, the image is stabilized. There was a problem that could not be recorded.
Japanese Patent Laid-Open No. 5-214279 U.S. Pat. No. 4,303,924 Japanese Unexamined Patent Publication No. 63-60783 JP-A-8-174997 Japanese Patent No. 3478495 JP 2005-96254 A

An object of the present invention is to provide an ink set for inkjet recording that has long-term storage stability, can be cured even with low exposure energy, and can form a high-quality image.
Another object of the present invention is to provide an inkjet image recording method capable of forming a high-quality image while maintaining excellent fixability.

Specific means for solving the above-mentioned problems are as follows.
<1> An ink set for ink jet recording comprising at least a first liquid and a second liquid each having a different composition, and comprising a plurality of types of liquids,
The first liquid contains at least one cleavage type polymerization initiator,
The second liquid contains at least one of a hydrogen abstraction polymerization initiator and a sensitizer;
An ink set for ink-jet recording, wherein at least one of the plurality of liquids contains a polymerizable compound.

  <2> The ink set for ink jet recording according to <1>, wherein the first liquid and the second liquid contain a polymerizable compound.

  <3> At least one of the cleavage type polymerization initiator, the hydrogen abstraction type polymerization initiator, and the sensitizer is dissolved in the polymerizable compound, <1> or <1> 2>. The ink set for inkjet recording according to 2>.

  <4> The ink set for inkjet recording according to any one of <1> to <3>, wherein a colorant is contained in at least one of the plurality of liquids.

  <5> The ink set for ink jet recording according to any one of <1> to <4>, wherein the second liquid contains a thioxanthone compound.

  <6> The ink set for ink jet recording according to any one of <1> to <5>, wherein the second liquid contains an amine compound.

<7> The ink set for inkjet recording according to any one of <1> to <6>, including at least a first liquid and a second liquid and including a plurality of types of liquids,
Inkjet for forming an image by simultaneously applying the first liquid and the second liquid onto a recording medium, or applying either one first and the other afterwards so that both liquids are in contact with each other. This is an image recording method.

  <8> The inkjet image recording method according to <7>, wherein the means for applying the first liquid and the second liquid onto the recording medium is ejection by an inkjet nozzle.

  <9> The inkjet image recording method according to <7> or <8>, wherein a step of applying energy to an image formed on the recording medium to fix the image is provided.

  <10> The inkjet image recording method according to <9>, wherein a light emitting diode having a central wavelength of active energy rays of 365 ± 20 nm is used as the energy irradiation light source.

According to the present invention, it is possible to provide an ink set for inkjet recording that has long-term storage stability, can be cured even with low exposure energy, and can form a high-quality image.
In addition, according to the present invention, it is possible to provide an inkjet image recording method capable of forming a high-quality image while maintaining excellent fixability.

The ink set for ink jet recording of the present invention (hereinafter sometimes simply referred to as “ink set”) includes at least a first liquid and a second liquid having different compositions, and is an ink jet composed of a plurality of types of liquids. A recording ink set, wherein the first liquid contains at least one cleavage type polymerization initiator, and the second liquid is at least one of a hydrogen abstraction type polymerization initiator and a sensitizer. An ink set for ink-jet recording, comprising a seed, wherein at least one of the plurality of liquids contains a polymerizable compound.
The ink set for ink-jet recording of the present invention is excellent in long-term storage stability due to the above configuration, can effectively suppress bleeding and droplet ejection interference, and can be cured even with low exposure energy. Therefore, a high-quality image can be formed with such an ink set.

In addition, in the inkjet image recording method of the present invention (hereinafter sometimes simply referred to as “image recording method”), the first liquid and the second liquid are simultaneously applied onto the recording medium, or either This is an inkjet image recording method in which an image is formed by applying one first and then the other. The application of the first liquid and the second liquid onto the recording medium is more preferably performed by jetting with an inkjet nozzle from the viewpoint of productivity and downsizing of the recording apparatus.
Hereinafter, in describing the present invention in detail, first, components constituting the above-mentioned plural kinds of liquids will be described.

<Cleavage polymerization initiator>
The cleavage type polymerization initiator in the present invention is a polymerization initiator that is cleaved by the application of energy rays to generate initiating species such as radicals.
It is necessary that at least one cleavage-type polymerization initiator is contained in the first liquid in the ink set of the present invention.

  Examples of the cleavage type polymerization initiator include acetophenone compounds, benzoin compounds, ketoxime ester compounds, acyl phosphine oxide compounds, and the like.

  Examples of the acetophenone compounds include 2,2-diethoxyacetophenone, 2-hydroxymethyl-1-phenylpropan-1-one, 4′-isopropyl-2-hydroxy-2-methyl-propiophenone, 2- Hydroxy-2-methyl-propiophenone, p-dimethylaminoacetone, p-tert-butyldichloroacetophenone, p-tert-butyltrichloroacetophenone, p-azidobenzalacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl- 2-dimethylamino-1- (4-morpholinophenyl) butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-one, 1- [4- (2-hydroxyethoxy)- Phenyl] -2-hydroxy-2-methyl 1-propan 1-one, and the like.

  Examples of the ketoxime ester compound include 3-benzoyloxyiminobutan-2-one, 3-acetoxyiminobutane-2-one, 3-propionyloxyiminobutan-2-one, and 2-acetoxyiminopentane-3-one. 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-p-toluenesulfonyloxyiminobutan-2-one, 2-ethoxycarbonyloxy Examples include imino-1-phenylpropan-1-one.

  Examples of the benzoin-based compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, and benzyldimethyl ketal.

  Examples of the acylphosphine oxide-based compound include bis (2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl) phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2, 4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-2-ethylhexanoyldiphenylphosphine oxide, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2 , 3,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,3,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trichlorobenzoyldiphenylphosphine Down oxide, and the like.

  Among the above-mentioned cleavage-type polymerization initiators, acetophenone compounds and acylphosphine oxide compounds are preferable, and specific compounds include 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- ( 4-morpholinophenyl) butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2 -Methyl-1-propan-1-one, bis (2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl) phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2, 4,6-trimethylbenzoyl) -phenylphosphine oxide is preferred Arbitrariness.

Only one type of cleavage polymerization initiator may be used alone, or two or more types may be used in combination.
In the ink set of the present invention, the content of the cleavage type polymerization initiator contained in the first liquid is preferably 1 to 30% by mass, and 2 to 15% by mass in the liquid from the viewpoint of curability. More preferably, 5-10 mass% is still more preferable.

<Hydrogen extraction type polymerization initiator>
The hydrogen abstraction-type polymerization initiator in the present invention is a polymerization initiator that generates hydrogen or other starting species due to the generation of hydrogen by application of energy rays.
At least one hydrogen abstraction type polymerization initiator is contained in the second liquid in the ink set of the present invention alone or in combination with a sensitizer described later. In addition, the 2nd liquid in this invention also contains the aspect which does not contain a hydrogen abstraction type polymerization initiator but contains only a sensitizer.

  Examples of the hydrogen abstraction type polymerization initiator include benzophenone compounds, thioxanthone compounds, benzyl compounds, and quinone derivatives.

  Examples of the benzophenone compounds include benzophenone, methyl o-benzoylbenzoate, Michler's ketone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, and the like.

  Examples of the thioxanthone compound include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone and the like can be mentioned.

  Examples of the benzyl compound include benzyl and benzyl-β-methoxyethyl acetal.

  Examples of the quinone derivative include 2-ethylanthraquinone and 9,10-phenanthrenequinone.

  As described above, the hydrogen abstraction type initiator is preferably a thioxanthone compound, and specific compounds are preferably isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and 1-chloro-4-propoxythioxanthone.

In the ink set of the present invention, the content of the hydrogen abstraction type polymerization initiator contained in the first liquid is preferably 0.4 to 15% by mass in the liquid from the viewpoint of curability. The mass% is more preferable, and 2 to 5 mass% is still more preferable.
A hydrogen abstraction type initiator may be used individually by 1 type, and may use 2 or more types together.

  When a hydrogen abstraction initiator and a sensitizer described later are used in combination, the content ratio (mass ratio) between the hydrogen abstraction initiator and the sensitizer is preferably 20:80 to 80:20, 30 : 70 to 70:30 is more preferable, and 40:60 to 60:40 is particularly preferable.

  In addition, as a preferable combination of the cleavage type polymerization start contained in the first liquid and the hydrogen abstraction type initiator contained in the second liquid, an acetophenone compound and a thioxanthone compound, an acylphosphine oxide compound and a thioxanthone Combinations of system compounds are preferred.

<Sensitizer>
The 2nd liquid in the ink set of this invention contains a sensitizer individually or in the aspect used together with the said hydrogen abstraction type polymerization initiator. From the viewpoint of curing with low exposure energy, an embodiment in which the hydrogen extraction type polymerization initiator is used in combination is preferable.

The sensitizer contained in the second liquid in the present invention is preferably an amine compound. Examples of the amine compound include N, N-diethylaniline, o-toluidine, p-toluidine, diphenylamine, triphenylamine, α-naphthylamine, N, N, N ′, N′-tetramethylethylenediamine, diethylenetriamine, N-ethyl. Diethanolamine, trioctylamine, tetraethylenepentamine, diethanolamine, methyl-4-dimethylaminobenzoate, ethyl-4-dimethylaminobenzoate, ethyl-4-diethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, 2-n- Examples thereof include aminobenzoate compounds such as butoxyethyl-4-dimethylaminobenzoate, isoamyl-4-dimethylaminobenzoate, and 2- (dimethylamino) ethylbenzoate.
Among these, aminobenzoate compounds are preferable, and specific compounds are preferably ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, and isoamyl-4-dimethylaminobenzoate.

In the ink set of the present invention, the content of the sensitizer contained in the second liquid is preferably 0.2 to 12% by mass in the liquid from the viewpoint of curability and ink physical properties. 8 mass% is more preferable, and 1-4 mass% is still more preferable.
The content ratio (mass ratio) of the content ratio (mass ratio) between the hydrogen abstraction initiator and the sensitizer when the hydrogen abstraction initiator and the sensitizer are used in combination is as described above.

It is preferable that at least one of the cleavage type polymerization initiator, the hydrogen abstraction type polymerization initiator, and the sensitizer described above is dissolved in the polymerizable compound described later from the viewpoint of ink jet discharge properties.
In the present invention, it is preferable that all of the cleavage type polymerization initiator, the hydrogen abstraction type polymerization initiator, and the sensitizer are dissolved in the polymerizable compound.

<Polymerizable compound>
In the ink set of the present invention, it is an essential requirement that at least one of a plurality of liquids constituting the ink set contains a polymerizable compound, and from the viewpoint of curability, the first liquid and the second liquid. Preferably contains a polymerizable compound.

The polymerizable compound has a function of causing a polymerization reaction and curing by an initiating species such as a radical generated from a polymerization initiator.
Such a polymerizable compound is preferably an addition polymerizable compound having at least one ethylenically unsaturated double bond, and preferably has at least one terminal ethylenically unsaturated bond, more preferably two or more. It is preferably selected from functional compatible compounds. Such a compound group is widely known in the industrial field, and these can be used without particular limitation in the present invention. These include, for example, those having chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof and copolymers thereof.

  The polymerizable compound preferably has a polymerizable group such as an acryloyl group, a methacryloyl group, an allyl group, a vinyl group, an internal double bond group (such as maleic acid) in the molecule, and among them, an acryloyl group or a methacryloyl group. Is preferable because it can cause a curing reaction with low energy.

Examples of the polyfunctional polymerizable compound that can be used in the present invention include a vinyl group-containing aromatic compound, a (meth) acrylate that is an ester of a divalent or higher alcohol and (meth) acrylic acid, a divalent or higher amine, and a (meth). (Meth) acrylamide which is an amide with acrylic acid, polyester (meth) acrylate in which (meth) acrylic acid is introduced into an ester or polycaprolactone obtained by combining polybasic acid and dihydric alcohol, alkylene oxide and polyhydric alcohol Polyether (meth) acrylate with (meth) acrylic acid introduced into the ether obtained by bonding, (meth) acrylic acid introduced into epoxy resin, or obtained by reacting a dihydric or higher alcohol with an epoxy-containing monomer Epoxy (meth) acrylate, urethane acrylate with urethane bond , Amino resin acrylate, acrylic resin acrylate, alkyd resin acrylate, spirane resin acrylate, silicone resin acrylate, reaction product of unsaturated polyester and photopolymerizable monomer, and reaction product of wax and polymerizable monomer. , (Meth) acrylates, polyester (meth) acrylates, polyether (meth) acrylates, epoxy acrylates, urethane acrylates, acrylic resin acrylates, silicone resin acrylates, reaction products of unsaturated polyesters and the above photopolymerizable monomers are preferred, acrylates Polyester acrylate, polyether acrylate, epoxy acrylate, and urethane acrylate are particularly preferable.
In this specification, when referring to either or both of acrylic acid and methacrylic acid, “(meth) acrylic acid” may be used.

  Specific examples of the polyfunctional polymerizable compound include, for example, divinylbenzene, 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate. 1,6-acryloylaminohexane, hydroxypivalate ester neopentylglycol diacrylate, polyester acrylate having a (meth) acryloyl group at the molecular chain end of a polyester having a molecular weight of 500 to 30,000 consisting of a dibasic acid and a dihydric alcohol, polyethylene Glycol diacrylate, epoxy acrylate containing bisphenol (A or S, F) skeleton having a molecular weight of 450 to 30,000, skeleton of phenol novolac resin Epoxy acrylate with a molecular weight of 600 to 30,000 with the reaction of a polyvalent isocyanate and a hydroxyl group (meth) acrylate monomer having a molecular weight of 350 to 30,000, also urethane-modified product having a urethane bond in the molecule.

  Examples of the monofunctional polymerizable monomer that can be used in the present invention include (meth) acrylate, styrene, acrylamide, vinyl group-containing monomers (vinyl esters, vinyl ethers, N-vinyl amide, etc.), (meth) acrylic acid, and the like. (Meth) acrylates, acrylamides, vinyl esters and vinyl ethers are preferred, and (meth) acrylates and acrylamides are particularly preferred. These polymerizable monomers may have a substituent, and examples of the substituent that can be introduced include a halogen atom, a hydroxyl group, an amide group, and a carboxylic acid group.

  Specific examples of the monofunctional polymerizable monomer include, for example, hydroxyethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, 2-acryloyloxyethyl phosphate, allyl acrylate, N, N-dimethylaminoethyl acrylate. N, N-dimethylacrylamide, N, N-diethylaminopropylacrylamide, N-butoxymethylacrylamide, acryloylmorpholine, 2-hydroxyethyl vinyl ether, N-vinylformamide, N-vinylacetamide, 2-cyclohexylcarbamoyloxyethyl acrylate, ester Acrylate containing polybutyl acrylate moiety in the ester and acrylate containing polydimethylsiloxane moiety in the ester Such as theft and the like.

  Only one type of polymerizable compound may be used in one liquid, or two or more types may be used in combination. In the first liquid and the second liquid, the same type of polymerizable compound may be used, or different polymerizable compounds may be used.

In the plural types of liquids constituting the ink set, the content of the polymerizable compound contained in one liquid is preferably in the range of 50 to 99% by mass, more preferably in the range of 70 to 97% by mass, and 80 to 95%. A range of mass% is more preferred.
When it is less than these ranges, it may not be possible to sufficiently cure, and when it is more, it may not be possible to contain a necessary amount of components such as a colorant contained as desired, which is not preferable.

  When the polymerizable compound is contained in both the first liquid and the second liquid, when the content of the polymerizable compound contained in the second liquid is 100 parts by mass, the polymerization contained in the first liquid The content of the functional compound is preferably 1 to 1,000 parts by mass, more preferably 5 to 100 parts by mass, and still more preferably 10 to 50 parts by mass.

  As the content of the polymerizable compound and the polymerization initiator contained in the first liquid or the second liquid, from the viewpoint of storage stability, when the content of the polymerization initiator is 100 parts by mass, the polymerization property is increased. The content of the compound is preferably 100 to 10,000 parts by weight, more preferably 200 to 5,000 parts by weight, and still more preferably 500 to 1,000 parts by weight.

<Colorant>
The plurality of liquids constituting the ink set of the present invention can contain a colorant in at least one of them. By containing a colorant in the liquid constituting the ink set, a colored image can be formed.

  The colorant used in the present invention is not particularly limited, and can be appropriately selected from known water-soluble dyes, oil-soluble dyes and pigments as long as they can achieve a hue and color density suitable for the intended use of the ink. be able to. Among these, the liquid constituting the ink set of the present invention is preferably a water-insoluble liquid and does not contain an aqueous solvent from the viewpoint of ink droplet stability and quick-drying. It is preferable to use an oil-soluble dye or pigment that is easily dispersed and dissolved in a water-soluble liquid.

(Oil-soluble dye)
There is no restriction | limiting in particular in the oil-soluble dye which can be used for this invention, Arbitrary things can be used. Hereinafter, oil-soluble dyes that can be used in the present invention are exemplified for each hue.
Examples of yellow dyes include phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components; open-chain active methylene compounds as coupling components. Azomethine dyes; methine dyes such as benzylidene dyes and monomethine oxonol dyes; quinone dyes such as naphthoquinone dyes and anthraquinone dyes, and the like. Other dye species include quinophthalone dyes, nitro / nitroso dyes, Examples include acridine dyes and acridinone dyes.

  Examples of magenta dyes include aryl or heteryl azo dyes having phenols, naphthols, and anilines as coupling components; azomethine dyes having pyrazolones and pyrazolotriazoles as coupling components; arylidene dyes, styryl dyes, and merocyanine dyes Methine dyes such as oxonol dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, quinone dyes such as naphthoquinone, anthraquinone and anthrapyridone, condensed polycyclic dyes such as dioxazine dyes Etc.

  Examples of cyan dyes include indoaniline dyes, indophenol dyes, or azomethine dyes having pyrrolotriazoles as coupling components; polymethine dyes such as cyanine dyes, oxonol dyes, and merocyanine dyes; diphenylmethane dyes, triphenylmethane dyes, xanthenes Examples thereof include carbonium dyes such as dyes; phthalocyanine dyes; anthraquinone dyes; aryl or heteryl azo dyes having phenols, naphthols and anilines as coupling components, and indigo / thioindigo dyes.

  Each of the above-mentioned dyes may exhibit yellow, magenta, and cyan colors only after a part of the chromophore group is dissociated. In this case, the counter cation may be an alkali metal or ammonium. It may be an inorganic cation, may be an organic cation such as pyridinium or quaternary ammonium salt, and may further be a polymer cation having them in a partial structure.

  In the case of using an oil-soluble dye as the colorant, the content of the dye is preferably in the range of 0.05 to 20% by mass in terms of solid content in the liquid containing the colorant, and 0.1 to 15% by mass. % Is more preferable, and 0.2 to 6% by mass is particularly preferable.

(Pigment)
An embodiment in which a pigment is used as the colorant is also preferable from the viewpoint that aggregation easily occurs when a plurality of liquids are mixed.
The pigment is not particularly limited, and all commercially available organic and inorganic pigments or pigments dispersed in an insoluble resin or the like as a dispersion medium, or the resin is grafted on the pigment surface Can be used. Moreover, what dye | stained the resin particle with dye can be used.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include, for example, C.I. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. A monoazo pigment such as C.I. Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine type azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Pigment yellow 128, C.I. I. Pigment yellow 93, C.I. I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).

  Examples of red or magenta colors include C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as C.I. Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Azo lake pigments such as C.I. Pigment Red 57: 1 (Brilliant Carmine 6B); I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Red 174 (Phloxine B Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G ′ Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (Thioindigo Bordeaux, etc.); I. Perinone pigments such as C.I. Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.); I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Quinacridone pigments such as CI Pigment Red 122 (quinacridone magenta, etc.); I. Isoindolinone pigments such as CI Pigment Red 180 (isoindolinone red 2BLT, etc.); I. And alizarin lake pigments such as CI Pigment Red 83 (Mada Lake, etc.).

  Examples of pigments exhibiting blue or cyan colors include C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Phthalocyanine pigments such as C.I. Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

Examples of green pigments include C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).
Examples of the orange pigment include C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

Examples of black pigments include carbon black, titanium black, and aniline black.
Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Strontium titanate (SrTiO ₃ , so-called titanium strontium white) or the like can be used.

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a large hiding power and coloring power as a pigment. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used as necessary.

For dispersing the pigment, use a dispersing device such as a ball mill, sand mill, attritor, roll mill, jet mill, homogenizer, paint shaker, kneader, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, etc. Can do.
It is also possible to add a dispersant when dispersing the pigment. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular weight copolymer, a modified polyacrylate, an aliphatic polyacrylate. Carboxylic acid, naphthalenesulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester, pigment derivative and the like. It is also preferable to use a commercially available polymer dispersant such as the Solsperse series from Zeneca.
Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

  As a dispersion medium for various components such as pigments, a solvent may be added, or the polymerizable compound which is a low molecular weight component without a solvent may be used as a dispersion medium. It is preferably a radiation curable type, and is solvent-free because it is cured after the ink is applied onto the recording medium. This is because if the solvent remains in the cured ink image, the solvent resistance is deteriorated or a VOC (Volatile Organic Compound) problem of the remaining solvent occurs. From such a viewpoint, it is preferable to use a polymerizable compound as the dispersion medium.

  The volume average particle diameter of the pigment particles contained in the liquid in the present invention is preferably in the range of 30 to 250 nm, more preferably 50 to 200 nm, from the viewpoint of balance between optical density and storage stability. . Here, the volume average particle diameter of the pigment particles can be measured by a measuring device such as LB-500 (manufactured by HORIBA).

In the case of using a pigment as the colorant, the content of the pigment in the liquid containing the colorant is in the range of 0.1% by mass to 20% by mass in terms of solid content from the viewpoint of optical density and jetting stability. Preferably, it is in the range of 1% by mass to 10% by mass.
The colorant may be used alone or in combination of two or more. Further, different colorants may be used for each liquid, or the same may be used.

<Ink set for inkjet recording>
The ink set for ink-jet recording of the present invention includes at least the first ink (liquid) and the second liquid described above, and is composed of a plurality of types of liquids.
The plurality of liquids according to the present invention include a first liquid containing at least one cleavage polymerization initiator, and at least one of a hydrogen abstraction polymerization initiator and a sensitizer. A plurality of kinds of liquids including at least the second liquid are used, and at least one of the plurality of kinds of liquids contains a polymerizable compound.

Here, an ink set for inkjet recording will be described by taking a two-component type consisting of a first liquid and a second liquid as an example.
<1> A combination in which the first liquid contains a cleavage type polymerization initiator and a polymerizable compound, and the second liquid contains a hydrogen abstraction type polymerization initiator, a sensitizer, a polymerizable compound, and a colorant,
<2> A combination in which the first liquid contains a cleavage type polymerization initiator and a polymerizable compound, and the second liquid contains a hydrogen abstraction type polymerization initiator, a polymerizable compound, and a colorant,
Can be illustrated.

  In addition, as an ink set for ink jet recording in the case of a three-component type, a cleavage type polymerization initiator and a polymerizable compound are used in a first liquid, and a hydrogen abstraction type polymerization initiator, a sensitizer, and a polymer are used in a second liquid. Examples include a combination in which the functional compound and the colorant contain the hydrogen abstraction polymerization initiator, the sensitizer, the polymerizable compound, and the colorant in the third liquid.

<Other ingredients>
In addition to the components described above, the following additives can be used in combination with the liquids of the present invention in accordance with the purpose.

(High boiling point organic solvent)
In the present invention, in any one or more of a plurality of liquids, (1) the viscosity at 25 ° C. is 100 mPa · s or less or the viscosity at 60 ° C. is 30 mPa · s or less, (2) A high-boiling organic solvent having a boiling point higher than 100 ° C. can be contained.
By containing the high boiling organic solvent, it is possible to more effectively prevent bleeding and droplet ejection interference.
From the viewpoint of further suppressing the occurrence of bleeding and droplet ejection interference, the high boiling point organic solvent is more preferably contained in a liquid not containing a colorant.

In a high boiling point organic solvent that does not satisfy any of the above viscosity conditions (1), the viscosity becomes high, which may hinder the application of the liquid onto the recording medium. On the other hand, a high-boiling organic solvent that does not satisfy the boiling point condition (2) may have a boiling point that is too low to evaporate during image formation, thereby hindering the effect of avoiding droplet ejection interference according to the present invention. Also, it is not preferable from the environmental aspect that it is evaporated and released into the atmosphere.
Of the above conditions (1), the viscosity at 25 ° C. is preferably 70 mPa · s or less, more preferably 40 mPa · s or less, and particularly preferably 20 mPa · s or less. . The viscosity at 60 ° C. is further preferably 20 mPa · s or less, and particularly preferably 10 mPa · s or less. Moreover, the boiling point which is the condition of (2) is more preferably 150 ° C. or higher, and particularly preferably 170 ° C. or higher. Furthermore, the high-boiling organic solvent preferably has a melting point of 80 ° C. or lower and a water solubility (25 ° C.) of 4 g or lower. The solubility of water is further preferably 3 g or less, more preferably 2 g or less, and particularly preferably 1 g or less.

  Here, the “viscosity” in the present invention refers to a viscosity obtained using a RE80 viscometer manufactured by Toki Sangyo Co., Ltd. The RE80 type viscometer is a conical rotor / plate type viscometer corresponding to the E type. Measurement is performed at a rotation speed of 10 rpm using the first rotor. However, for those having a viscosity higher than 60 mPa · s, measurement is performed by changing the number of revolutions to 5 rpm, 2.5 rpm, 1 rpm, 0.5 rpm, or the like as necessary.

  In the present invention, “water solubility” is the saturation concentration of water in a high-boiling organic solvent at 25 ° C., and means the mass (g) of water that can be dissolved in 100 g of the high-boiling organic solvent at 25 ° C. .

  As the usage-amount of the said high boiling point organic solvent, 5-2000 mass% is preferable in conversion of coating amount with respect to the coloring agent to be used, and 10-1000 mass% is more preferable.

  In the present invention, the high-boiling organic solvent is preferably a compound represented by the following formulas [S-1] to [S-9].

In the formula [S-1], R ₁ , R ₂ and R ₃ each independently represents an aliphatic group or an aryl group. A, b and c each independently represent 0 or 1;

In the formula [S-2], R ₄ and R ₅ each independently represents an aliphatic group or an aryl group, and R ₆ represents a halogen atom (F, Cl, Br, I and so on), an alkyl group, an alkoxy group, Represents an aryloxy group, an alkoxycarbonyl group or an aryloxycarbonyl group, and d represents an integer of 0 to 3. When d is plural, plural R ₆ may be the same or different.

In the formula [S-3], Ar represents an aryl group, e represents an integer of 1 to 6, and R ₇ represents an e-valent hydrocarbon group or a hydrocarbon group bonded to each other through an ether bond.

In the formula [S-4], R ₈ represents an aliphatic group, f represents an integer of 1 to 6, and R ₉ represents an f-valent hydrocarbon group or a hydrocarbon group bonded to each other through an ether bond.

In the formula [S-5], g represents an integer of 2 to 6, R ₁₀ represents a g-valent hydrocarbon group (excluding an aryl group), and R ₁₁ represents an aliphatic group or an aryl group.

In the formula [S-6], R ₁₂ , R ₁₃ and R ₁₄ each independently represents a hydrogen atom, an aliphatic group or an aryl group. X represents —CO— or —SO ₂ —. R ₁₂ and R ₁₃ or R ₁₃ and R ₁₄ may be bonded to each other to form a ring.

In the formula [S-7], R ₁₅ represents an aliphatic group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an aryl group or a cyano group, and R ₁₆ represents a halogen atom, an aliphatic group or an aryl group. Represents a group, an alkoxy group or an aryloxy group, and h represents an integer of 0 to 3. When h is plural, plural R ₁₆ may be the same or different.

In the formula [S-8], R ₁₇ and R ₁₈ each independently represents an aliphatic group or an aryl group, R ₁₉ represents a halogen atom, an aliphatic group, an aryl group, an alkoxy group or an aryloxy group, and i Represents an integer of 0 to 5. When i is plural, plural R ₁₉ may be the same or different.

In the formula [S-9], R ₂₀ and R ₂₁ each independently represents an aliphatic group or an aryl group. j represents 1 or 2; R ₂₀ and R ₂₁ may be bonded to each other to form a ring.

In the formulas [S-1] to [S-9], when R _{1 to} R ₆ , R ₈ and R _{11 to} R ₂₁ are an aliphatic group or a group containing an aliphatic group, the aliphatic group is a straight chain, It may be branched or cyclic, and may contain an unsaturated bond or may have a substituent. Examples of the substituent include a halogen atom, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, a hydroxyl group, an acyloxy group, and an epoxy group.

In the formulas [S-1] to [S-9], R _{1 to} R ₆ , R ₈ and R _{11 to} R ₂₁ are cyclic aliphatic groups, that is, cycloalkyl groups, or groups containing cycloalkyl groups. Sometimes, the cycloalkyl group may contain an unsaturated bond in the 3- to 8-membered ring, and may have a substituent or a bridging group. Examples of the substituent include a halogen atom, an aliphatic group, a hydroxyl group, an acyl group, an aryl group, an alkoxy group, and an epoxy group, and examples of the crosslinking group include methylene, ethylene, isopropylidene, and the like.

In the formulas [S-1] to [S-9], when R _{1 to} R ₆ , R _{11 to} R ₂₁ , Ar is an aryl group or a group containing an aryl group, the aryl group is a halogen atom, aliphatic group, aryl It may be substituted with a substituent such as a group, an alkoxy group, an aryloxy group, or an alkoxycarbonyl group.

In the formulas [S-3], [S-4], and [S-5], when R ₇ , R _9, or R ₁₀ is a hydrocarbon group, the hydrocarbon group is a cyclic structure (for example, a benzene ring, a cyclopentane ring, A cyclohexane ring) or an unsaturated bond, and may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an acyloxy group, an aryl group, an alkoxy group, an aryloxy group, and an epoxy group.

Hereinafter, among the high boiling point organic solvents represented by the formulas [S-1] to [S-9], particularly preferred high boiling point organic solvents will be described.
In the formula [S-1], R ₁ , R ₂ and R ₃ are each independently an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms (for example, n-butyl, n-hexyl, n -Octyl, EH-octyl, 2-ethylhexyl, 3,3,5-trimethylhexyl, 3,5,5-trimethylhexyl, n-dodecyl, n-octadecyl, benzyl, oleyl, 2-chloroethyl, 2,3-dichloro Propyl, 2-butoxyethyl, 2-phenoxyethyl, cyclopentyl, cyclohexyl, 4-t-butylcyclohexyl, 4-methylcyclohexyl) or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, phenyl, Cresyl, p-nonylphenyl, xylyl, cumenyl, p-methoxyphenyl, p-methoxycarbonylphenyl) are preferred Yes. Among these, R ₁ , R ₂ and R ₃ are particularly n-hexyl, n-octyl, EH-octyl, 2-ethylhexyl, 3,5,5-trimethylhexyl, n-dodecyl, 2-chloroethyl, 2- Butoxyethyl, cyclohexyl, phenyl, cresyl, p-nonylphenyl and cumenyl are preferred.
a, b, and c are each independently 0 or 1, and more preferably, all of a, b, and c are 1.

In the formula [S-2], R ₄ and R ₅ are each independently an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms (for example, the same group as the aliphatic group mentioned for R ₁ above). , Heptyl, ethoxycarbonylmethyl, 1,1-diethylpropyl, 2-ethyl-1-methylhexyl, cyclohexylmethyl, 1-ethyl-1,5-dimethylhexyl, 3,5,5-trimethylcyclohexyl, menthyl, bornyl, 1-methylcyclohexyl) or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aryl group mentioned for R ₁ , 4-t-butylphenyl, 4-t-octylphenyl, 1, 3,5-trimethylphenyl, 2,4, -di-t-butylphenyl, 2,4, -di-t-pentylphenyl) are preferred. Among these, R ₄ and R ₅ are more preferably aliphatic groups, and particularly preferably n-butyl, heptyl, 2-ethylhexyl, n-dodecyl, 2-butoxyethyl, and ethoxycarbonylmethyl.
R ₆ is a halogen atom (preferably a chlorine atom), an alkyl group having 1 to 18 carbon atoms (eg, methyl, isopropyl, t-butyl, n-dodecyl), an alkoxy group having 1 to 18 carbon atoms (eg, methoxy, n -Butoxy, n-octyloxy, methoxyethoxy, benzyloxy), an aryloxy group having 6 to 18 carbon atoms (for example, phenoxy, p-tolyloxy, 4-methoxyphenoxy, 4-t-butylphenoxy) or 2 carbon atoms A C-19 alkoxycarbonyl group (for example, methoxycarbonyl, n-butoxycarbonyl, 2-ethylhexyloxycarbonyl) or an aryloxycarbonyl group having 6 to 25 carbon atoms is preferred. Among these, R ₆ is more preferably an alkoxycarbonyl group, and particularly preferably n-butoxycarbonyl.
d is 0 or 1.

In the formula [S-3], Ar is an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, phenyl, 4-chlorophenyl, 2,4-dichlorophenyl, 4-methoxyphenyl, 1-naphthyl, 4- n-butoxyphenyl, 1,3,5-trimethylphenyl, 2- (2-n-butoxycarbonylphenyl) phenyl) are preferable, and among these, Ar is phenyl, 2,4-dichlorophenyl, 2- (2 -N-Butoxycarbonylphenyl) phenyl is preferred.
e is an integer of 1 to 4 (preferably 1 to 3).
R ₇ is an e-valent hydrocarbon group having 2 to 24 (preferably 2 to 18) carbon atoms [for example, the aliphatic group mentioned above for R ₄ , n-octyl, the aryl group mentioned for R ₄ ,-( CH _{2) 2} -,

] Or an e-valent hydrocarbon group having 4 to 24 (preferably 4 to 18) carbon atoms and bonded to each other by an ether bond [for example, —CH ₂ CH ₂ OCH ₂ CH ₂ —, —CH ₂ CH ₂ (OCH _{2 CH 2) 3 -, - CH} 2 CH 2 CH 2 OCH 2 CH 2 CH 2 -,

] Is preferable. Among these, R ₇ is more preferably an alkyl group, and particularly preferably n-butyl, n-octyl and 2-ethylhexyl.

In the formula [S-4], R ₈ is an aliphatic group having 1 to 24 (preferably 1 to 17) carbon atoms (for example, methyl, n-propyl, 1-hydroxyethyl, 1-ethylpentyl, n-heptyl, n - undecyl, n- tridecyl, pentadecyl, 8,9-epoxy heptadecyl, cyclopropyl, cyclohexyl, 4-methylcyclohexyl). among them, R ₈ in particular, n- heptyl, n- tridecyl, 1-hydroxy Ethyl, 1-ethylpentyl, and 8,9-epoxyheptadecyl are preferred.
f is an integer of 1 to 4 (preferably 1 to 3).
R ₉ is a hydrocarbon group having 2 to 24 (preferably 2 to 18) f-valent carbon atoms or a hydrocarbon group linked to each other by an ether bond having 4 to 24 (preferably 4 to 18) f-valent carbon atoms. (For example, the groups mentioned for R ₇ , 1-methyl-2-methoxyethyl, 2-hexyldecyl) are preferable, and among these, R ₉ is particularly 2-ethylhexyl, 2-hexyldecyl, 1-methyl-2. -Methoxyethyl,

Is preferred.

In the formula [S-5], g is 2 to 4 (preferably 2 or 3).
R ₁₀ represents a g-valent hydrocarbon group [for example, —CH ₂ —, — (CH ₂ ) ₂ —, — (CH ₂ ) ₄ —, — (CH ₂ ) ₇ —, — (CH ₂ ) ₈ —,

Among these, R ₁₀ is particularly — (CH ₂ ) ₄ —, — (CH ₂ ) ₈ —,

Is preferred.
R ₁₁ is an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms, or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aliphatic groups mentioned for R ₄ above, Aryl group). Among these, R ₁₁ is more preferably an alkyl group, and n-butyl, n-octyl, and 2-ethylhexyl are particularly preferable.

In the formula [S-6], R ₁₂ is a hydrogen atom, an aliphatic group having 1 to 24 carbon atoms (preferably 3 to 20) [for example, n-propyl, 1-ethylpentyl, n-undecyl, n-pentadecyl, 2,4-di-t-pentylphenoxymethyl, 4-t-octylphenoxymethyl, 3- (2,4-di-t-butylphenoxy) propyl, 1- (2,4-di-t-butylphenoxy) propyl Cyclohexyl, 4-methylcyclohexyl, 8-N, N-diethylcarbamoyloctyl], or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aryl group mentioned for Ar, 3-methylphenyl) , 2-(N, N-di -n- octylcarbamoyl) phenyl). among them, R ₁₂ is especially, n- undecyl, 8-N, N-di Ji carbamoyl octyl, 3-methylphenyl, 2-(N, N-di -n- octylcarbamoyl) phenyl are preferred.
R ₁₃ and R ₁₄ are each a hydrogen atom or an aliphatic group having 1 to 24 (preferably 1 to 18) carbon atoms (eg, methyl, ethyl, isopropyl, n-butyl, n-hexyl, n-octyl, 2-ethylhexyl). , N-dodecyl, n-tetradecyl, cyclopentyl, cyclopropyl) or an aryl group having 6 to 18 carbon atoms (preferably 6 to 15) (for example, phenyl, 1-naphthyl, p-tolyl), among these, R ₁₃ and R ₁₄ are particularly preferably methyl, ethyl, n-butyl, n-octyl, n-tetradecyl and phenyl.
R ₁₃ and R ₁₄ may be bonded to each other to form a pyrrolidine ring, piperidine ring or morpholine ring together with N, and R ₁₂ and R ₁₃ may be bonded to each other to form a pyrrolidone ring or piperidine ring together with N. Also good.
X is —CO— or —SO ₂ —, and preferably X is —CO—.

In the formula [S-7], R ₁₅ is an aliphatic group having 1 to 24 (preferably 3 to 18) carbon atoms (for example, methyl, isopropyl, t-butyl, t-pentyl, t-hexyl, t-octyl, 2 -Butyl, 2-hexyl, 2-octyl, 2-dodecyl, 2-hexadecyl, t-pentadecyl, cyclopentyl, cyclohexyl), an alkoxycarbonyl group having 2 to 24 (preferably 5 to 17) carbon atoms (for example, n-butoxy) Carbonyl, 2-ethylhexyloxycarbonyl, n-dodecyloxycarbonyl), aryloxycarbonyl group having 7 to 24 carbon atoms (preferably 7 to 18) (for example, phenoxycarbonyl group, naphthoxycarbonyl group, cresyloxycarbonyl group) An alkylsulfonyl group having 1 to 24 (preferably 1 to 18) carbon atoms ( For example, methylsulfonyl, n-butylsulfonyl, n-dodecylsulfonyl), arylsulfonyl groups having 6 to 30 carbon atoms (preferably 6 to 24) (for example, p-tolylsulfonyl, p-dodecylphenylsulfonyl, p-hexadecyloxy) Phenylsulfonyl), an aryl group having 6 to 32 carbon atoms (preferably 6 to 24 carbon atoms) (for example, phenyl, p-tolyl), or a cyano group is preferable, and among these, R ₁₅ is further having 1 to 24 carbon atoms. An aliphatic group and an alkoxycarbonyl group having 1 to 24 carbon atoms are more preferable, and an aliphatic group having 1 to 24 carbon atoms is particularly preferable.
R ₁₆ is a halogen atom (preferably Cl), an aliphatic group having 1 to 24 carbon atoms (preferably 1 to 18 carbon atoms) {more preferably an alkyl group (for example, the alkyl groups mentioned for R ₁₅ above), carbon atoms 3-18 (more preferably 5-17) cycloalkyl group (for example, cyclopentyl, cyclohexyl)}, aryl group having 6-32 (preferably 6-24) carbon atoms (for example, phenyl, p-tolyl), carbon atom An alkoxy group of 1 to 24 (preferably 1 to 18) (for example, methoxy, n-butoxy, 2-ethylhexyloxy, benzyloxy, n-dodecyloxy, n-hexadecyloxy) or 6 to 32 carbon atoms (preferably Is an aryloxy group (for example, phenoxy, pt-butylphenoxy, pt-octylphenoxy, m-pen) Decylphenoxy, p- dodecyloxy-phenoxy). Among them, R ₁₆ is further more preferably an aliphatic group having 1 to 24 carbon atoms, particularly preferably an aliphatic group having 1 to 12 carbon atoms.
h is an integer of 1-2.

In the formula [S-8], preferred examples of R ₁₇ and R ₁₈ are the same as the examples other than the hydrogen atom in R ₁₃ and R ₁₄ , and among these, R ₁₇ and R ₁₈ further have an aliphatic group. More preferred are n-butyl, n-octyl and n-dodecyl. However, R ₁₇ and R ₁₈ are not bonded to each other to form a ring.
Preferred examples of R ₁₉ are the same as R ₁₆ described above, and among these, R ₁₉ is more preferably an alkyl group and an alkoxy group, and particularly preferably n-octyl, methoxy, n-butoxy and n-octyloxy. .
i is an integer of 1-5.

In the formula [S-9], preferred examples of R ₂₀ and R ₂₁ are the same as those of R ₁ , R ₂ and R ₃ when they are not bonded to form a ring. Among these, R ₂₀ and R ₂₁ Is particularly preferably a substituted or unsubstituted aliphatic group having 1 to 24 carbon atoms.
R ₂₀ and R ₂₁ may be bonded to each other to form a ring, and the formed ring is preferably a 3- to 10-membered ring, particularly preferably a 5- to 7-membered ring.
j represents 1 or 2, and preferably j is 1.

  In the present invention, the high-boiling organic solvent may be used alone or in combination of two or more [for example, tricresyl phosphate and dibutyl phthalate, trioctyl phosphate and di (2-ethylhexyl) sebacate, dibutyl phthalate and poly (Nt-butylacrylamide)] may be used.

  In the present invention, the mass ratio between the colorant and the high-boiling organic solvent is preferably 1: 0.01 to 1: 1, and 1: 0.05 to the colorant: high-boiling organic solvent. More preferably, it is 1: 0.5.

  Examples of other high boiling point organic solvents used in the present invention and / or methods for synthesizing these high boiling point organic solvents include, for example, U.S. Pat. Nos. 2,322,027 and 2,533,514. 2,772,163, 2,835,579, 3,594,171, 3,676,137, 3,689,271, 3, 700,454, 3,748,141, 3,764,336, 3,765,897, 3,912,515, 3,936,303, 4,004,928, 4,080,209, 4,127,413, 4,193,802, 4,207,393, 4,220 No.711, No.4,239,851, No.4,278,75 No. 4,353,979, No. 4,363,873, No. 4,430,421, No. 4,430,422, No. 4,464,464, No. 4 No. 4,483,918, No. 4,540,657, No. 4,684,606, No. 4,728,599, No. 4,745,049, No. 4,935,321. 5,013,639, European Patent Nos. 276,319A, 286,253A, 289,820A, 309,158A, 309,159A, 309, No. 160A, No. 509,311A, No. 510,576A, East German Patent Nos. 147,009, No. 157,147, No. 159,573, No. 225,240A, British Patent No. 2 , 091,124A, etc. 47335, 50-26530, 51-25133, 51-26036, 51-27921, 51-27922, 51-149028, 52-46816, 53-1520 53-1521, 53-15127, 53-146622, 54-91325, 54-106228, 54-118246, 55-59464, 56-64333, 56-81836, 59-204041, 61-84441, 62-118345, 62-247364, 63-167357, 63-214744, 63-301941, 64 -9452, 64-9454, 64-68745, JP-A-1-101543, 1-102454 No. 2-792, No. 2-4239, No. 2-43541, No. 4-29237, No. 4-30165, No. 4-232946, No. 4-346338, etc. ing.

(Storage stabilizer)
In the present invention, a storage stabilizer can be added for the purpose of suppressing undesirable polymerization during storage of a plurality of types of liquids. The storage stabilizer is preferably used in the same liquid as the polymerizable compound, and it is preferable to use a storage stabilizer that is soluble in the liquid or other coexisting components.
Storage stabilizers include quaternary ammonium salts, hydroxyamines, cyclic amides, nitriles, substituted ureas, heterocyclic compounds, organic acids, hydroquinones, hydroquinone monoethers, organic phosphines, copper compounds, and the like. Specific examples include benzyltrimethylammonium chloride, diethylhydroxylamine, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, citric acid, hydroquinone monomethyl ether, hydroquinone monobutyl ether, and copper naphthenate. It is done.
The addition amount of the storage stabilizer is preferably adjusted as appropriate based on the activity of the polymerization initiator used, the polymerizability of the polymerizable compound, and the type of the storage stabilizer. However, the storage stability and the curability of the ink during liquid mixing are preferred. From the standpoint of balance, the amount is preferably 0.005 to 1% by mass in terms of solid content in the liquid, more preferably 0.01 to 0.5% by mass, and still more preferably 0.01 to 0.2% by mass. .

(Conductive salts)
Conductive salts are solid compounds that improve conductivity. In the present invention, it is preferable not to use it substantially because there is a great concern of precipitation during storage, but it is possible to increase the solubility of conductive salts or use a highly soluble liquid component. If it is good, an appropriate amount may be added. Examples of conductive salts include potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride and the like.

(solvent)
The solvent can be used for improving the polarity, viscosity, surface tension, solubility and dispersibility of the coloring material, adjusting the conductivity and adjusting the printing performance. The solvent is preferably a water-insoluble liquid and does not contain an aqueous solvent from the viewpoint of ink droplet ejection stability and quick drying, and the above-described high boiling point organic solvents are particularly preferable.
The low boiling point organic solvent is an organic solvent having a boiling point of 100 ° C. or lower. There is a concern that the low boiling point organic solvent affects the curability, and it is desirable not to use the low boiling point organic solvent in consideration of environmental pollution. When used, it is preferable to use a highly safe solvent, and a highly safe solvent is a solvent having a high management concentration (an index indicated by the work environment evaluation criteria), preferably 100 ppm or more, More preferably, it is 200 ppm or more. Specific examples include alcohols, ketones, esters, ethers, hydrocarbons, and the like, and specific examples include methanol, 2-butanol, acetone, methyl ethyl ketone, ethyl acetate, and tetrahydrofuran.

  One or more solvents may be used in combination, and the amount used in the case of using the water and / or low boiling point organic solvent is preferably 0 to 20% by mass, and 0 to 10% by mass in each liquid. More preferably, it is particularly preferred that it is substantially free. Here, “substantially not containing” means accepting the presence of inevitable impurities. When water is contained in the liquid, it becomes non-uniform over time, the turbidity of the liquid is caused by the precipitation of dyes, etc., and the drying characteristics when a non-water-absorbing recording medium is used. It is not preferable from the viewpoint.

(Other additives)
As other additives, known additives such as polymers, surface tension adjusters, ultraviolet absorbers, antioxidants, fading inhibitors and pH adjusters can be used in combination.
Regarding the surface tension adjusting agent, ultraviolet absorber, antioxidant, anti-fading agent, and pH adjusting agent, known compounds may be appropriately selected and used. For example, JP-A-2001-181549 discloses a specific example. The additives described can be used.

In addition to the above, a set of compounds that react by mixing to form aggregates or thicken can be contained in different liquids. The one set of compounds has a feature of rapidly forming aggregates or rapidly thickening the liquid, thereby more effectively suppressing occurrence of droplet ejection interference with adjacent droplets. be able to.
Examples of reaction of a set of compounds that react by the above mixing to form aggregates or thicken are acid / base reactions, hydrogen bonding reactions with carboxylic acid / amide group-containing compounds, and boronic acids / diols. Crosslinking reaction, reaction by electrostatic interaction with cations / anions, and the like.

<Inkjet image recording method>
Next, the inkjet image recording method of the present invention will be described.
The inkjet image recording method of the present invention (hereinafter sometimes simply referred to as “image recording method”) uses a plurality of kinds of liquids including the first liquid and the second liquid, and the first liquid. And the second liquid is applied onto the recording medium at the same time, or one of them is applied first, the other is applied thereafter, and both liquids are in contact with each other to form an image.

(Liquid application means)
In the above image recording method, it is not always necessary to apply a plurality of types of liquids including the first liquid and the second liquid onto the recording medium by ejection from the inkjet nozzle, but by other means such as coating. Although it may be applied, it is preferable to apply both the first liquid and the second liquid onto the recording medium by jetting with an ink jet nozzle, and further, at the same time or when the first liquid is applied. After that, it is preferable that the second liquid is ejected by an ink jet nozzle from the viewpoint of suppression of bleeding and droplet ejection interference.

  Here, the means for applying the liquid onto the recording medium in the image recording method will be described. The providing means is not particularly limited, but specific examples include the following two points.

(I) Coating using a coating apparatus As one aspect of the liquid application means in the inkjet image recording method of the present invention, either one of the first liquid and the second liquid is applied onto a recording medium using a coating apparatus. A mode in which an image is formed by applying and then spraying the other with an ink jet nozzle so as to come into contact with the previously applied liquid is exemplified.
The coating device is not particularly limited and may be appropriately selected from known coating devices according to the purpose. For example, an air doctor coater, blade coater, lot coater, knife coater, squeeze coater, impregnation coater, reverse roll coater , Transfer roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, extrusion coater and the like. For details, see Yuji Harasaki's “Coating Engineering”.
Moreover, there is no restriction | limiting in particular as said inkjet nozzle, A well-known nozzle can be suitably selected according to the objective. The ink jet nozzle (ink jet system) will be described in detail later.
The liquid other than the first liquid and the second liquid may be applied to the recording medium by any method, such as application by the application device or injection by an ink jet nozzle, and the application timing is also possible. Although not particularly limited, when a colorant is contained, means by jetting with an inkjet nozzle is preferable.

(Ii) Injection by inkjet nozzle In addition, either one of the first liquid and the second liquid is ejected by the inkjet nozzle, and at the same time or after that, the other is similarly contacted with the liquid previously ejected by the inkjet nozzle. A mode in which an image is formed by jetting in such a manner is mentioned.
The inkjet nozzle is the same as described above.
Similarly to the above, the liquid other than the first liquid and the second liquid may be applied to the recording medium by any method, such as application by the above-described application apparatus or injection by an inkjet nozzle. The timing is also not particularly limited, but when a colorant is contained, means by jetting with an inkjet nozzle is preferable.

  The ink set for ink jet recording of the present invention described above is the means (ii) above, and is excellent in its effect when used in an ink jet image recording method in which all other liquids are ejected by ink jet nozzles. Is remarkably exhibited.

Here, the ejection method (inkjet recording method) using the inkjet nozzle will be described. In the present invention, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electric signal is converted into an acoustic beam into ink. Known systems such as an acoustic ink jet system that irradiates and discharges ink using radiation pressure, and a thermal ink jet (bubble jet (registered trademark)) system that uses ink to form bubbles by heating ink and generate pressure Are preferably used.
The ink jet recording method includes a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving the image quality using a plurality of inks having substantially the same hue and different concentrations, and a colorless and transparent type. A method using ink is included.

In the case of the above means (i), one of the first liquid and the second liquid is applied onto the recording medium to which the other liquid has already been applied by such an ink jet recording method. An image is formed. On the other hand, in the case of the above means (ii), at least the first liquid and the second liquid are applied onto the recording medium simultaneously or sequentially by such an ink jet recording method to form an image.
When two or more kinds of liquids are ejected onto the recording medium by the above-described ink jet recording method, the liquids are applied so as to come into contact with each other. There is no restriction | limiting in particular in the aspect which 2 or more types of liquids contact, You may spray so that it may mutually adjoin, You may spray so that it may become the same area | region as the application | coating area | region of one liquid.
The timing of jetting is arbitrary and may be simultaneous or sequential. However, in the case of jetting sequentially, the next liquid may be jetted within 1 second after jetting the first liquid. preferable. The mass of the droplet is not particularly limited and is selected according to the sharpness of the image to be formed. In general, the mass per droplet of one liquid is about 0.5 pl to 10 pl. Is preferred.

  In either case of the above means (i) and (ii), the first liquid and the second liquid are previously applied to the recording medium to which both liquids are applied at the same time or the other liquid. Since the liquid to be applied later is ejected so as to come into contact with the applied liquid, droplet ejection interference does not occur and the dot shape is maintained. From the viewpoint of maintaining a better dot shape, it is preferable that the liquid previously applied onto the recording medium is applied in a wider range than the range in which the liquid to be applied later is to be ejected.

  Further, in the case of the two-liquid type, the balance of the amount of liquid applied per droplet applied to the image forming unit is the amount of liquid applied first when the amount of liquid applied later is 1. (Mass ratio) is preferably in the range of 0.05 to 5, more preferably in the range of 0.07 to 1, and particularly preferably in the range of 0.1 to 1. When the ratio of the liquid to be applied later to the liquid to be applied first is 5 or less, good image quality can be obtained from the viewpoint of relief, and when it is 0.05 or more, the effect of the present invention is achieved. The droplet ejection interference is sufficiently avoided.

  The overlap rate when droplets are ejected with overlapping portions is the overlap rate at least one second after the droplets are superimposed and ejected, and in particular, the previously applied droplet was ejected. It is preferable that the droplets be ejected so that the overlapping rate at the overlapping portion after 1 second from the droplets applied later is 10% or more and 90% or less. It is effective for higher resolution image recording. Among these, the overlapping rate is preferably 20% or more and 80% or less, and more preferably 30% or more and 70% or less.

  The overlapping rate is an index indicating at what rate the adjacent droplets (droplet a1, droplet a2,...) Overlap. Assuming that the diameter of the droplet after landing on the recording medium is a, the overlap ratio is 50% when ½a overlaps. In the case of the present invention, adjacent droplets that are ejected adjacently can maintain the droplet ejection shape without being united with each other, but the overlapping rate is defined as b being the radius of the droplet one second after droplet ejection. When the interval between adjacent droplets is c, 100 × (2b−c) / 2b [%].

  In addition, after the liquid to be applied is first applied to the recording medium, the droplet ejection interval from when the liquid droplet to be applied later is ejected is within the range of 5 μs or more and 400 msec or less. preferable. It is effective in that the effect of the present invention can be remarkably exhibited when the droplet ejection interval is within the above range. The droplet ejection interval is more preferably 10 μs or more and 300 ms or less, and particularly preferably 20 μs or more and 200 μs or less.

In addition, although the preferable physical property of the liquid (ink) injected on a recording medium by the said inkjet recording system changes with printing apparatuses, generally the viscosity of each liquid has preferable 5-100 mPa * s, 10- 80 mPa · s is more preferable. The surface tension of the ink composition is preferably 20 to 60 mN / m, and more preferably 30 to 50 mN / m.
More preferable physical properties are that the difference in viscosity is within 25 mPa · s and the surface tension is within 20 mN / m in the relationship between the first liquid and the second liquid.

(Energy application process)
Further, in the image recording method of the present invention, from the viewpoint of obtaining excellent fixability, a step of fixing an image by applying energy after image formation can be provided. By applying energy, polymerization and curing reaction in the aggregate can be promoted, and a stronger image can be formed more efficiently. Such energy application is preferably performed by light irradiation or heating.

  By applying energy such as exposure and heating, the generation of active species due to decomposition of the polymerization initiator in the mixed liquid is promoted, and the increase in the active species and the temperature increase cause the polymerization of the polymerizable compound resulting from the active species. The polymerization curing reaction is accelerated.

In the present invention, ultraviolet light, visible light, or the like can be used as an exposure light source for proceeding polymerization of the polymerizable compound. In addition, energy can be applied by irradiating radiation other than light, for example, α rays, γ rays, X rays, electron beams, etc. Among them, it is cost and safety to use ultraviolet rays and visible rays. In view of the above, it is more preferable to use ultraviolet rays.
In particular, in the present invention, a light emitting diode having an active energy ray center wavelength of 365 ± 20 nm can be suitably used as an energy irradiation light source, and an excellent cured image can be obtained even with low exposure energy. .
The amount of energy required for the curing reaction varies depending on the type and content of the polymerization initiator, but is generally about 500 to 5000 mJ / cm ² .

In addition, when energy is applied by heating, it is preferable to heat for 0.1 seconds to 1 second under the condition that the temperature of the recording medium surface is in a temperature range of 40 to 80 ° C.
This heating is performed using a non-contact type heating means, and preferably a heating means for passing through a heating furnace such as an oven, a heating means for performing whole surface exposure with ultraviolet light to visible light to infrared light, and the like. Used. Here, examples of the light source used for the exposure as the heating means include a metal halide lamp, a xenon lamp, a tungsten lamp, a carbon arc lamp, and a mercury lamp.

  In addition, it is possible to include a process of curing with the actinic ray between droplets of the liquid previously applied to the recording medium and the liquid subsequently applied, but it is not cured at all or semi-cured. Is a preferred embodiment.

(Recording medium)
In the present invention, both an ink-permeable recording medium and an ink-impermeable recording medium can be used. Examples of the ink permeable recording medium include plain paper, inkjet exclusive paper, coated paper, electrophotographic co-paper, cloth, non-woven fabric, porous film, polymer absorber and the like. These are described as “recording materials” in Japanese Patent Application Laid-Open No. 2001-181549.

The excellent effect of the present invention is remarkably exhibited in an ink non-permeable recording medium. Examples of the ink-impermeable recording medium include art paper, synthetic resin, rubber, resin-coated paper, glass, metal, earthenware, and wood. In addition, in order to add a function, a base material obtained by combining and combining a plurality of these materials can also be used.
As the synthetic resin, any synthetic resin can be used. For example, polyesters such as polyethylene terephthalate and polybutadiene terephthalate, polyolefins such as polyvinyl chloride, polystyrene, polyethylene, polyurethane, and polypropylene, acrylic resins, polycarbonates, acrylonitrile-butadiene- Examples include styrene copolymer, diacetate, triacetate, polyimide, cellophane, celluloid, etc. The thickness and shape of these synthetic resin substrates may be in the form of a film, card or block, and are not limited in any way. Never happen. These synthetic resins may be transparent or opaque.
As a usage form of the synthetic resin, it is also preferable to use a film used for so-called soft packaging, and various non-absorbable plastics and films thereof can be used. Examples of various plastic films include PET films and OPS films. , OPP film, PNy film, PVC film, PE film, TAC film and the like. As other plastics, polycarbonate, acrylic resin, ABS, polyacetal, PVA, rubbers and the like can be used.

  Examples of the resin-coated paper include a transparent polyester film, an opaque polyester film, an opaque polyolefin resin film, and a paper support obtained by laminating both sides of a paper with a polyolefin resin. Particularly preferred is a polyolefin resin on both sides of the paper. It is a paper support laminated with.

  Any metal can be used as the metal, but these composite materials such as aluminum, iron, gold, silver, copper, nickel, titanium, chromium, molybdenum, silicon, lead, zinc, or stainless steel are preferable. Used.

  The support used in the inkjet image recording method of the present invention further includes read-only optical disks such as CD-ROM and DVD-ROM, write-once optical disks such as CD-R and DVD-R, and rewritable optical disks. Can also be used, and an ink receiving layer and a gloss imparting layer can be provided on the label surface side.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not restrict | limited to these.

<Preparation of pigment dispersion>
First, a pigment, a dispersant and a polymerizable composition shown in Table 1 were placed in a ball mill and dispersed using a zircon bead having a diameter of 0.6 mm for 16 hours to obtain a cyan pigment dispersion and a magenta pigment dispersion. Obtained. The average particle size of the pigment dispersion was measured with a transmission electron microscope (TEM). The measurement results are shown in Table 1.

1. Preparation of first liquid (liquid containing cleavage type polymerization initiator) <Preparation of liquid for ink jet recording (I-M1) containing colorant>
Monomer: Caprolactone-modified dipentaerythritol hexaacrylate 6.0 g
(DPCA60, manufactured by SARTOMER)
Monomer: 1,6 hexanediol diacrylate 14.0 g
(HDDA, manufactured by Daicel UCB)
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl ketone and
Bis (2.6-dimethoxybenzoyl) 2,4,4-trimethyl-
1.4g of mixture with pentylphosphine oxide
(Irgacure 1870, manufactured by Ciba Specialty Chemicals)
Colorant: Magenta pigment dispersion shown in Table 1 4.0 g
The above components were mixed and dissolved by stirring to obtain a magenta inkjet recording liquid (I-M1).

<Preparation of Inkjet Recording Liquid (I-M2) Containing Colorant>
In the preparation of the ink jet recording liquid (I-M1), instead of Irgacure 1870 1.4 g used as a photopolymerization initiator, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1- On (Irgacure 907, manufactured by Ciba Specialty Chemicals) Magenta inkjet recording liquid (I-M2) containing a colorant was used in the same manner as inkjet recording liquid (I-M1) except that 1.4 g was used. Prepared.

<Preparation of Inkjet Recording Liquid (I-M3) Containing Colorant>
In the preparation of the ink jet recording liquid (I-M1), instead of Irgacure 1870 1.4 g used as a photopolymerization initiator, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone- 1 (Irgacure 369, manufactured by Ciba Specialty Chemicals Co., Ltd.) A magenta inkjet recording liquid (I-M3) containing a colorant was used in the same manner as the inkjet recording liquid (I-M1) except that 1.4 g was used. Prepared.

<Preparation of Inkjet Recording Liquid (I-M4) Containing Colorant>
In the preparation of the inkjet recording liquid (I-M1), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (DAROCUR TPO, Ciba Specialty) was used instead of 1.4 g of Irgacure 1870 used as a photopolymerization initiator. A magenta ink jet recording liquid (I-M4) containing a colorant was prepared in the same manner as the ink jet recording liquid (I-M1) except that 1.4 g was used.

<Preparation of ink-jet recording liquid (I-M5) containing colorant>
In the preparation of the inkjet recording liquid (I-M1), instead of 1.4 g of Irgacure 1870 used as a photopolymerization initiator, bis (2,4,6-trimethylbenzoyl) -phenyl-phosphine oxide (Irgacure 919, Ciba Colored in the same manner as the ink jet recording liquid (I-M1) except that 1.4 g was used except that 1.4 g was used (speciality chemicals) and 1.4 g was used. A magenta inkjet recording liquid (I-M5) containing an agent was prepared.

<Preparation of Inkjet Recording Liquid (I-C1) Containing Colorant>
Monomer: Ethoxylated pentaerythritol hexaacrylate 10.0 g
(SR494, manufactured by SARTOMER)
Monomer: 1,6 hexanediol diacrylate 10.0 g
(HDDA, manufactured by Daicel UCB)
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl ketone and
Bis (2.6-dimethoxybenzoyl) 2,4,4-trimethyl
-Mixture with pentylphosphine oxide 1.4 g
(Irgacure 1870, manufactured by Ciba Specialty Chemicals)
Colorant: 2.0 g of cyan pigment dispersion shown in Table 1
The above components were stirred, mixed and dissolved to obtain a cyan inkjet recording liquid (I-C1).

<Preparation of Inkjet Recording Liquid (I-C2) Containing Colorant>
Monomer: Ethoxylated pentaerythritol hexaacrylate 10.0 g
(SR494, manufactured by SARTOMER)
Monomer: 1,6 hexanediol diacrylate 10.0 g
(HDDA, manufactured by Daicel UCB)
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl ketone and
Bis (2.6-dimethoxybenzoyl) 2,4,4-trimethyl
-Mixture with pentylphosphine oxide 1.4 g
(Irgacure 1870, manufactured by Ciba Specialty Chemicals)
0.6 g of N-ethyldiethanolamine
Colorant: 2.0 g of cyan pigment dispersion shown in Table 1
The above components were stirred, mixed and dissolved to obtain a cyan inkjet recording liquid (I-C2).

<Preparation of ink-jet recording liquid (Ia-1) containing no colorant>
Monomer: Caprolactone-modified dipentaerythritol hexaacrylate 6.0 g
(DPCA60, manufactured by SARTOMER)
Monomer: 1,6 hexanediol diacrylate 14.0 g
(HDDA, manufactured by Daicel UCB)
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl ketone and
Bis (2.6-dimethoxybenzoyl) 2,4,4-trimethyl-
1.4g of mixture with pentylphosphine oxide
(Irgacure 1870, manufactured by Ciba Specialty Chemicals)
Surfactant: Megafac F-475 (Dainippon Ink Chemical Co., Ltd.) 0.05 g
The above components were mixed and dissolved with stirring to obtain an ink jet recording liquid (Ia-1).

<Preparation of liquid for ink jet recording (Ia-2) containing no colorant>
Monomer: 20.0 g of dipropylene glycol diacrylate
(DPGDA: manufactured by Daicel UCB)
Photopolymerization initiator: 2-methyl-1- [4- (methylthio) phenyl]
-2-morpholino-1-one 1.4 g
(Irgacure 907, manufactured by Ciba Specialty Chemicals)
Surfactant: Gafac F-475 (Dainippon Ink Chemical Co., Ltd.) 0.1g
The above components were mixed and dissolved by stirring to obtain an ink jet recording liquid (Ia-2).

2. Preparation of second liquid (liquid containing hydrogen abstraction type polymerization initiator and sensitizer) <Preparation of liquid for ink jet recording (II-C1) containing colorant>
Monomer: Ethoxylated pentaerythritol hexaacrylate 10.0 g
(SR494: manufactured by SARTOMER)
Monomer: 1,6 hexanediol diacrylate 10.0 g
(HDDA Daicel UCB Co., Ltd.)
Photoinitiator: Isopropylthioxanthone 0.5g
(DAROCUR ITX, manufactured by Ciba Specialty Chemicals)
Sensitizer: Ethyl-4-dimethylaminobenzoate 0.5g
(DAROCUR EDB, manufactured by Ciba Specialty Chemicals)
Colorant: 2.0 g of cyan pigment dispersion shown in Table 1
(DAROCUR EDB, manufactured by Ciba Specialty Chemicals)
The above components were mixed and dissolved with stirring to obtain a cyan inkjet recording liquid (II-C1) containing a colorant.

<Preparation of ink-jet recording liquid (II-C2) containing colorant>
In the preparation of the inkjet recording liquid (II-C1), 2,4-diethylthioxanthone (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) was used instead of 0.5 g of DAROCUR ITX used as a photopolymerization initiator. A cyan inkjet recording liquid (II-C2) containing a colorant was prepared in the same manner as the inkjet recording liquid (II-C1) except that 0.5 g was used.

<Preparation of ink-jet recording liquid (II-C3) containing colorant>
In the preparation of the inkjet recording liquid (II-C1), 2-chlorothioxanthone (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) was used instead of DAROCUR ITX 0.5 g used as a photopolymerization initiator. A cyan ink jet recording liquid (II-C3) containing a colorant was prepared in the same manner as the ink jet recording liquid (II-C1) except that 5 g was used.

<Preparation of ink-jet recording liquid (II-C4) containing colorant>
In the preparation of the inkjet recording liquid (II-C1), the inkjet recording liquid (II-C1) was used except that 0.5 g of benzophenone was used instead of 0.5 g of DAROCUR ITX used as a photopolymerization initiator. Similarly, a cyan inkjet recording liquid (II-C4) containing a colorant was prepared.

<Preparation of ink-jet recording liquid (II-C5) containing colorant>
In the preparation of the ink jet recording liquid (II-C1), p-dimethylaminobenzoic acid isoamyl ester (KAYACURE DMBI, manufactured by Nippon Kayaku Co., Ltd.) was used instead of 0.5 g of DAROCUR EDB used as a sensitizer. A cyan inkjet recording liquid (II-C5) containing a colorant was prepared in the same manner as the inkjet recording liquid (II-C1) except that 0.5 g was used.

<Preparation of Inkjet Recording Liquid Containing Colorant (II-C6)>
In the preparation of the inkjet recording liquid (II-C1), an inkjet recording liquid (II-C1) was used except that 0.5 g of N-ethyldiethanolamine was used instead of 0.5 g of DAROCUR EDB used as a sensitizer. ) To prepare a cyan ink jet recording liquid (II-C6) containing a colorant.

<Preparation of inkjet recording liquid (IIb-1) containing no colorant>
Monomer: Ethoxylated pentaerythritol hexaacrylate 10.0 g
(SR494: manufactured by SARTOMER)
Monomer: 1,6 hexanediol diacrylate 10.0 g
(HDDA Daicel UCB Co., Ltd.)
Photopolymerization initiator: isopropylthioxanthone 0.5 g
(DAROCUR ITX, manufactured by Ciba Specialty Chemicals)
Sensitizer: Ethyl-4-dimethylaminobenzoate 0.5g
(DAROCUR EDB, manufactured by Ciba Specialty Chemicals)
The above components were mixed and dissolved with stirring to obtain an ink jet recording liquid (IIb-1).

<Preparation of inkjet recording liquid (IIb-1) containing no colorant>
Monomer: 1,6 hexanediol diacrylate 20.0 g
(HDDA, manufactured by Daicel UCB)
Photopolymerization initiator: 0.5 g of 2-chlorothioxanthone
(DAROCUR ITX, manufactured by Ciba Specialty Chemicals)
Sensitizer: 2-ethylhexyl-4-dimethylaminobenzoate 0.5g
(DAROCUR EHA, manufactured by Ciba Specialty Chemicals)
Surfactant: Megafac F-470 (Dainippon Ink Chemical Co., Ltd.) 0.1g
The above components were mixed and dissolved with stirring to obtain an ink jet recording liquid (IIb-2).

(Examples 1 to 21)
The ink jet recording ink sets of Examples 1 to 21 were obtained by combining the ink jet recording liquids (first liquid and second liquid) obtained as described above as shown in Tables 2 and 3. Examples 1 to 10 are magenta ink sets, and Examples 11 to 21 are cyan ink sets.

(Comparative Examples 1-6)
Inkjet recording ink sets of Comparative Examples 1 to 6 were prepared by combining the inkjet recording liquid (first liquid) containing the cleavage type polymerization initiator as shown in Tables 2 and 3. Comparative Examples 1 and 2 are magenta ink sets, and Comparative Examples 3 to 6 are cyan ink sets.

3. Evaluation method <Printing / exposure method>
A printing / exposure method using a two-component liquid will be described.
Of the ink-jet recording liquids (first liquid and second liquid) constituting the ink sets of the examples and comparative examples, a liquid containing no colorant was printed. Subsequently, the liquid containing a colorant was printed so as to overlap from above.
All the liquids were printed with an ink jet printer (an experimental machine manufactured by Microjet Co., Ltd. (trade name: ink jet experiment system IJET1000R), printing density: 300 dpi, droplet ejection frequency: 2 kHz, number of nozzles: 64, two-row arrangement).

  Here, a polyethylene terephthalate (PET) sheet (trade name: PPL / Xerox FILM for laser printers (OHP FILM)) having a thickness of 60 μm was used as the recording medium on which the above-described printing was performed.

After printing (droplet ejection) on a recording medium (media), exposure was performed with an ultraviolet light emitting diode (UV-LED) to form an image. As the UV-LED, “NCCU033” manufactured by Nichia Corporation was used. This LED outputs ultraviolet light having a wavelength of 365 nm from one chip. When a current of about 500 mA is applied, light of about 100 mW is emitted from the chip. A plurality of these are arranged at intervals of 7 mm, and a power of 0.3 W / cm ² can be obtained on the media surface. The time until exposure after droplet ejection and the exposure time can be changed according to the medium transport speed and the distance between the head and the LED in the transport direction. In this embodiment, the exposure is performed about 0.5 seconds after landing.
Depending on the setting of the distance to the medium and the conveyance speed, the exposure energy on the medium can be adjusted between 0.01 and 15 J / cm ² . In this embodiment, the exposure energy is adjusted according to the conveyance speed.
For the measurement of the exposure power and the exposure energy, a spectroradiometer “URS-40D” manufactured by USHIO INC. Was used, and a value obtained by integrating the wavelength between 220 nm and 400 nm was used.
In this embodiment, the printing and exposure tests are performed at 23 ° C. H. Conducted in a 60% environment.

<Curability evaluation>
Using each ink sets of Examples and Comparative Examples, by the method described above, after printing, the exposure at each exposure energy of ^{200mJ / cm 2, 700mJ / cm} 2, 2000mJ / cm 2, and 10000 mJ / cm ² went. The curability is determined by visualizing the degree of transfer of the colorant onto the quality paper when the quality media is layered on each recording medium (print sample) immediately after exposure and passed through the pressure roller (50 kg / cm ² ). It was evaluated with. The evaluation results are shown in Tables 2 and 3.
○: No transfer at all.
Δ: Partially transferred.
X: Almost all transferred.

<Abrasion resistance evaluation>
In each ink set, the printed surface of the recording medium (printed sample) which was not transferred at the lowest energy exposure was rubbed several times with an eraser, and the change of the printed surface was observed and evaluated according to the following criteria. The evaluation results are shown in Tables 2 and 3.
In addition, about the sample in which the image did not harden | cure in any exposure energy, the said evaluation was not implemented but it showed by "-".
○: No change ×: The printed surface is peeled off.

<Evaluation of droplet ejection interference performance>
(Line quality)
In the above printing step, each liquid was overlaid in a line shape, and the degree of droplet formation overlap (bleeding) was evaluated according to the following criteria. Specifically, the line overstrike means that one of the first liquid and the second liquid is ejected so that the five rows of lines touch each other, and after 10 seconds from the liquid ejection, One row of the other liquid was ejected.
A: The line thickness is uniform.
B: There are fine line thickness variations derived from the liquid puddle in some places on the line.
C: There is a clear line variation from the liquid pool on the line.

(Solid image quality)
In the printing process, each liquid was overprinted in a solid image, and the density unevenness was evaluated according to the following criteria. Specifically, the solid image-like overstrike means that one of the first liquid and the second liquid is ejected so that the 60-row line is in contact, and 10 seconds after the liquid ejection, The other liquid was ejected in such a way that the 50-line contacted. The evaluation results are shown in Tables 2 and 3.
A: Density unevenness is hardly observed.
B: Slight density unevenness is observed, but the level is satisfactory as a whole.
C: The solid image has density unevenness and the quality is inferior.

<Line color separation evaluation>
In the printing step, each liquid was overlaid in a line shape, and the color separation of the lines was evaluated according to the following criteria. The evaluation results are shown in Tables 2 and 3.
A: There is no color separation.
B: A slight color separation is observed, and a slight white spot is observed in the center.
C: The color is largely separated and a thick white spot is observed at the center.

<Ink heat resistance>
Each obtained ink jet recording liquid was stored in an oven at 60 ° C. for 4 weeks, and the viscosity (mPa) at 25 ° C. before and after storage was measured using a RE80L viscometer (manufactured by Toki Sangyo Co., Ltd.). It was evaluated with. The evaluation results are shown in Tables 2 and 3.
○: Increase in viscosity is less than 20% Δ: Increase in viscosity is 20% or more (not gelled)
×: Ink is gelled

  As shown in Table 2 and Table 3, the ink set of the example has an efficient and rapid curing reaction by applying energy by the LED, and is excellent in print image quality, and an image having high scratch resistance can be obtained. I understand. In addition, it can be seen that the ink sets of the examples have sufficient ink heat resistance and are excellent in long-term storage stability.

Claims (10)

An ink set for ink jet recording comprising at least a first liquid and a second liquid each having a different composition, and comprising a plurality of types of liquids,
The first liquid contains at least one cleavage type polymerization initiator,
The second liquid contains at least one of a hydrogen abstraction polymerization initiator and a sensitizer;
An ink set for inkjet recording, wherein at least one of the plurality of types of liquids contains a polymerizable compound.   The ink set for inkjet recording according to claim 1, wherein the first liquid and the second liquid contain a polymerizable compound.   The at least one of the cleavage type polymerization initiator, the hydrogen abstraction type polymerization initiator, and the sensitizer is dissolved in the polymerizable compound. Ink set for inkjet recording.   The ink set for inkjet recording according to any one of claims 1 to 3, wherein a colorant is contained in at least one of the plurality of liquids.   The ink set for inkjet recording according to any one of claims 1 to 4, wherein the second liquid contains a thioxanthone-based compound.   The ink set for inkjet recording according to any one of claims 1 to 5, wherein the second liquid contains an amine compound. The ink set for ink jet recording according to any one of claims 1 to 6, comprising at least a first liquid and a second liquid and comprising a plurality of types of liquids.
Inkjet for forming an image by simultaneously applying the first liquid and the second liquid onto a recording medium, or applying either one first and the other afterwards so that both liquids are in contact with each other. Image recording method.   8. The inkjet image recording method according to claim 7, wherein the means for applying the first liquid and the second liquid onto the recording medium is ejection by an inkjet nozzle.   9. The ink jet image recording method according to claim 7, further comprising a step of fixing energy by applying energy to an image formed on a recording medium.   10. The inkjet image recording method according to claim 9, wherein a light emitting diode having an active energy ray having a center wavelength of 365 ± 20 nm is used as the energy irradiation light source.