JP2010076138A - Ink set and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink set excellent in curing property and excellent in adhesiveness to a medium to be recorded, and to provide an inkjet recording method using the ink set. <P>SOLUTION: The ink set is characterized by comprising a coloring liquid comprising a cation polymerizable compound, a cation polymerization initiator and a coloring agent, and an undercoating liquid containing an optically acid-generating agent. The inkjet recording method is characterized by including an undercoating liquid applying process for applying the undercoating liquid to the medium to be recorded, an undercoating liquid semi-curing process for semi-curing the undercoating liquid, an image forming process for delivering the coloring liquid to the semi-cured undercoating liquid and performing image formation, and a completely-curing process for completely curing the undercoating liquid and the coloring liquid, and using the ink set as the ink set comprising the undercoating liquid and the coloring liquid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink set and an ink jet recording method.

  An ink jet system that ejects ink in droplets from an ink ejection port is used in many printers because it is small and inexpensive, and can form an image without contact with a recording medium. Among these inkjet methods, the piezo inkjet method that ejects ink using deformation of piezoelectric elements and the thermal inkjet method that ejects ink droplets using the boiling phenomenon of ink due to thermal energy are high resolution and high-speed printability. It has the characteristic that it is excellent in.

Currently, high sensitivity of ink and fixability to recording media are important issues when ink is ejected onto non-water-absorbing recording media such as plain paper or plastic by inkjet printers. Yes.
Ink jet recording is a method in which ink droplets are ejected according to image data, and lines are formed on the recording medium using these droplets, or an image is formed. In particular, as one of the studies aiming at higher image quality, a study has been conducted to increase the concentration of the colorant, but there is a problem that sufficient curing sensitivity cannot be obtained because the light transmittance to the deep part of the ink is reduced. ing.

For example, in order to give high-definition drawing properties, there is a method that uses a reactive two-component ink and causes both to react on the recording medium. For example, a liquid having a basic polymer is attached. Then, after applying a method of recording an ink containing an anionic dye (see, for example, Patent Document 1) or a liquid composition containing a cationic substance, an ink containing an anionic compound and a coloring material is applied. A method (for example, see Patent Document 2) and the like are disclosed.
In addition, UV curable ink is applied as the ink, and UV curable color ink dots ejected onto the recording medium are irradiated with ultraviolet rays in accordance with their respective ejection timings to increase the viscosity and adjacent dots do not mix with each other. There has been proposed an ink jet recording method in which pre-curing is performed to an extent, and then ultraviolet curing is further performed to perform main curing (see, for example, Patent Document 3).
In addition, a radiation-curable white ink is uniformly applied as an undercoat layer on a transparent or translucent non-absorbable recording medium, solidified or thickened by irradiation, and then a radiation-curable color ink set is used. There has been proposed a technique (for example, see Patent Documents 4 and 5) that improves the problem of color ink visibility, bleeding, and differences in images between various recording media. In addition, a technique has been proposed in which a substantially transparent actinic ray curable ink is applied by an inkjet head in place of the radiation curable white ink (see, for example, Patent Documents 6, 7, and 8).

Japanese Unexamined Patent Publication No. 63-60783 JP-A-8-174997 JP 2004-42548 A JP 2003-145745 A JP 2004-42525 A JP 2005-96254 A JP 2006-137185 A JP 2006-137183 A

  An object of the present invention is to provide an ink set having excellent curability and excellent adhesion to a recording medium, and an ink jet recording method using the ink set.

The above object of the present invention has been solved by means described in the following <1>, <8> and <9>. It describes below with <2>-<7> and <10> which are preferable embodiments.
<1> An ink set comprising a cationic polymerizable compound, a cationic polymerization initiator, a coloring liquid containing a coloring agent, and an undercoat liquid containing a photoacid generator,
<2> The ink set according to <1>, wherein the undercoat liquid further contains a cationic polymerizable compound.
<3> The ink set according to <1> or <2>, wherein the cationically polymerizable compound includes at least one oxetane group-containing compound and at least one oxirane group-containing compound,
<4> The ink set according to <1>, wherein the undercoat liquid further contains a radical polymerization initiator and a radical polymerizable compound.
<5> The ink set according to any one of <1> to <4>, wherein the undercoat liquid contains a surfactant.
<6> The ink set according to any one of <1> to <5>, wherein the surface tension γA of the coloring liquid and the surface tension γB of the undercoat liquid satisfy a relational expression of γA> γB.
<7> The ink set according to any one of <1> to <6>, which is for inkjet recording.
<8> An undercoat liquid applying step for applying an undercoat liquid onto a recording medium, a light irradiation step for irradiating the undercoat liquid with light to generate an acid, and discharging a colored liquid onto the undercoat liquid to form an image. An image forming process to be performed and a complete curing process for completely curing the undercoat liquid and the colored liquid, and the ink set including the undercoat liquid and the colored liquid is described in any one of <1> to <7> An ink jet recording method comprising using an ink set of
<9> An undercoat liquid applying step for applying an undercoat liquid onto a recording medium, an undercoat liquid semi-curing step for semi-curing the undercoat liquid, and an image formation by discharging a colored liquid onto the semi-cured undercoat liquid An ink set including the undercoating liquid and the coloring liquid, and the ink set including the undercoating liquid and the coloring liquid as any one of <1> to <7> An ink jet recording method comprising using the ink set described above,
<10> The method according to <9>, further including means for controlling a humidity of a region where the undercoat liquid is semi-cured and / or a region where the undercoat liquid is completely cured in the semi-curing step of the undercoating liquid and / or the complete curing step. Inkjet recording method.

  According to the present invention, it was possible to provide an ink set having excellent curability and excellent adhesion to a recording medium, and an ink jet recording method using the ink set.

(1) Ink set The ink set of the present invention includes at least a cationically polymerizable compound, a cationic polymerization initiator, a coloring liquid containing a coloring agent, and an undercoat liquid containing a photoacid generator. And
The ink set is suitable for ink jet recording. By using this ink set, it is possible to provide an ink set having high sensitivity in the deep part of the ink and excellent fixability (adhesion) to the recording medium. It becomes possible.
The main requirements constituting the ink set of the present invention will be described in detail below.

(Coloring liquid)
Among the liquid compositions constituting the ink set of the present invention, the coloring liquid contains at least a cationic polymerizable compound, a cationic polymerization initiator, and a coloring agent. If necessary, in addition to the above components, a sensitizing dye, a surfactant, and the like may be contained.
By making the polymerizable compound contained in the coloring liquid into a cationic polymerizable compound, the amount of ink liquid applied per unit pixel is increased in order to print a high-density image or a high-saturation image, or the color contained in the ink Even when the agent concentration is increased, sufficient curability inside the film can be obtained.

  From the viewpoint of image fixability, the cationic polymerizable compound is preferably added in an amount of 40% by weight or more and 98% by weight or less, and 50% by weight or more and 95% by weight based on the total weight of the colored liquid. % Or less is more preferable, and 60% by weight or more and 90% by weight or less is particularly preferable. It is preferable for the addition amount of the cationic polymerizable compound to be in the above range since the curability is excellent and the viscosity is appropriate.

  The addition concentration of the cationic polymerization initiator is preferably 0.1 to 20.0% by weight, more preferably 0.5 to 18.0% by weight, still more preferably, based on the total weight of the colored liquid. 1.0 to 15.0% by weight. It is preferable that the addition amount of the cationic polymerization initiator is within the above range because it is excellent in curability and is appropriate from the viewpoint of reducing surface stickiness.

  The colorant is added in an amount of 50% by weight or less, more preferably 1% by weight or more and 30% by weight or less, and more preferably 2% by weight or more and 20% by weight or more based on the total weight of the color liquid. It is particularly preferable that the amount is not more than% by weight. It is preferable that the addition amount of the colorant be within the above range since good image density and storage stability can be obtained.

  The coloring liquid preferably contains a sensitizing dye, and the addition concentration of the sensitizing dye is preferably 0.1 to 15.0% by weight based on the total weight of the coloring liquid. Preferably it is 0.5-10.0 weight%, More preferably, it is 1.0-8.0 weight%. It is preferable for the amount added to be in the above range since good curability inside the film can be obtained.

The colored liquid may be a liquid at room temperature, but from the viewpoint of appropriate droplet ejection by ink jetting, the viscosity at 25 ° C. is preferably 100 mPa · s or less, or the viscosity at 60 ° C. is preferably 30 mPa · s or less, 25 ° C. The viscosity at is more preferably 60 mPa · s or less or the viscosity at 60 ° C. is 20 mPa · s or less, and the viscosity at 25 ° C. is particularly preferably 40 mPa · s or less or the viscosity at 60 ° C. is 15 mPa · s or less.
Similarly, the surface tension at 25 ° C. of the colored liquid is preferably 18 mN / m or more and 40 mN / m or less, more preferably 20 mN / m or more and 35 mN / m or less, and more preferably 22 mN / m or more and 32 mN / m from the viewpoint of ink jetting appropriateness. m or less is more preferable.
The “viscosity” here is a viscosity determined 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. The measurement was performed at a rotation speed of 10 rpm using the first rotor. However, for those having a viscosity higher than 60 mPa · s, the measurement was performed while changing the number of revolutions to 5 rpm, 2.5 rpm, 1 rpm, 0.5 rpm, or the like as necessary.
Here, the surface tension is measured at a liquid temperature of 25 ° C. by the Wilhelmy method using a generally used surface tension meter (for example, surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.). It is a measured value.

(Undercoat liquid)
Among the liquid compositions constituting the ink set for inkjet recording of the present invention, the undercoat liquid contains a photoacid generator.
When the undercoat liquid contains a photoacid generator that generates acid when irradiated with light, it becomes possible to increase the sensitivity of the colored liquid, and in particular, it is possible to improve the sensitivity of the deep part of the colored liquid, and adhesion to the substrate. An ink set and an image forming method excellent in the above can be provided.

  From the viewpoint of improving the sensitivity of the coloring liquid, the photoacid generator is preferably added to the undercoat liquid in an amount of 0.1 to 30.0% by weight, more preferably 0, based on the total weight of the undercoat liquid. 0.5 to 25.0 wt%, more preferably 1.0 to 20.0 wt%. It is preferable that the addition amount of the photoacid generator is within the above range since the curability of the deep portion of the colored liquid is excellent.

  The undercoat liquid preferably contains a photoacid generator and a cationically polymerizable compound. In this case, the content of the cationically polymerizable compound is preferably from 80% by weight to 99.9% by weight and more preferably from 82% by weight to 99.5% by weight with respect to the total weight of the undercoat liquid. Is more preferable, and it is further more preferable that it is 85 to 99 weight%. It is preferable for the content of the cationically polymerizable compound to be in the above range since the curability is excellent. The content of the photoacid generator contained in the undercoat liquid is preferably 0.1% by weight or more and 20.0% by weight or less, and 0.5% by weight or more and 18.5% by weight or less with respect to the total weight of the undercoat liquid. It is more preferably 0% by weight or less, and further preferably 1.0% by weight or more and 15.0% by weight or less. It is preferable for the content of the photoacid generator to be in the above range since the curability is excellent.

  The undercoat liquid can also contain a photoacid generator, a radical polymerization initiator, and a radical polymerizable compound. In this case, the content of the photoacid generator is preferably 0.1 wt% or more and 20.0 wt% or less with respect to the total weight of the undercoat liquid, and is 0.5 wt% or more and 18.0 wt%. More preferably, the content is 1.0% by weight or more and 15.0% by weight or less. Further, the content of the radical polymerizable compound is preferably 80.0 wt% or more and 99.9 wt% or less, more preferably 82.0 wt% or more and 99.5 wt% or less, and 85.0 wt%. More preferably, the content is not less than 9% by weight and not more than 99.0% by weight. In this case, the content of the radical polymerization initiator is more preferably 0.5% by weight or more and 18.0% by weight or less, and further preferably 1.0% by weight or more and 15.0% by weight or less. It is preferable that the addition amount of the photoacid generator, the radical polymerization initiator, and the radical polymerizable compound is within the above range because the curability is excellent.

  Furthermore, the undercoat liquid may be in an embodiment containing a photoacid generator and a solvent. In this case, the solvent to be used is not particularly limited as long as it is an organic solvent that dissolves the photoacid generator and does not deactivate the acid generated by light. Examples include ketones, esters, ethers, glycol ethers, alcohols and the like that do not inhibit the generated acid. Further, from the viewpoint of image quality performance of the printed matter, a highly volatile solvent is preferable, the boiling point at atmospheric pressure (1 atm) is preferably 40 ° C to 160 ° C, and more preferably in the range of 50 ° C to 150 ° C. .

  Among these, the undercoat liquid is preferably a photocurable composition containing at least a photoacid generator and a cationic polymerizable compound, and more preferably contains a surfactant in addition to these components.

  From the viewpoint of uniformly coating the recording medium, the viscosity of the undercoat liquid at 25 ° C. is preferably 1,000 mPa · s or less, or the viscosity at 60 ° C. is 300 mPa · s or less, and the viscosity at 25 ° C. is 600 mPa · s. The viscosity at s or less or 60 ° C. is more preferably 200 mPa · s or less, and the viscosity at 25 ° C. is particularly preferably 400 mPa · s or less or the viscosity at 60 ° C. is 150 mPa · s or less.

Similarly, from the viewpoint of uniformly coating on the recording medium, the surface tension of the undercoat liquid at 25 ° C. is preferably 16 mN / m or more and 38 mN / m or less, more preferably 18 mN / m or more and 33 mN / m or less, and 20 mN / m. More preferably, it is 30 mN / m or less.
Further, from the viewpoint of enhancing the color reproducibility of the image, the undercoat liquid preferably contains substantially no colorant or preferably contains a white pigment. The phrase “substantially does not contain a colorant” does not exclude the inclusion of a colorless and transparent dye / pigment or the inclusion of a trace amount of pigment that is invisible. The allowable amount is preferably 1% by weight or less, particularly preferably not contained, based on the total weight of the undercoat liquid. Moreover, the white pigment which can be preferably used is described in the item of (colorant).
Hereinafter, various components used in the coloring liquid and the undercoat liquid will be described.

(Cationically polymerizable compound)
The cationically polymerizable compound in the present invention is not particularly limited as long as it is a compound that generates and cures a cationic polymerization reaction by applying some energy, and can be used regardless of the type of monomer, oligomer, or polymer. Various known cationically polymerizable monomers known as photocationically polymerizable monomers that cause a polymerization reaction with an initiation species generated from a cationic polymerization initiator containing a photoacid generator described later can be used. The cationically polymerizable compound may be a monofunctional compound or a polyfunctional compound.

As the cationically polymerizable compound in the present invention, an oxetane ring-containing compound and an oxirane ring-containing compound are preferable from the viewpoint of curability and scratch resistance, and an oxetane group-containing compound (oxetane ring-containing compound) and an oxirane group-containing compound ( An embodiment containing both of the oxirane ring-containing compounds is more preferable.
Here, when the cationic polymerizable compound (1) is a cationic polymerizable compound contained in the colored liquid, and the cationic polymerizable compound (2) is a cationic polymerizable compound (2) contained in the undercoat liquid, the cationic polymerizable compound (1) and It is preferable that the cationically polymerizable compound (2) contains at least one oxetane group-containing compound and at least one oxirane group-containing compound.

  Here, in this specification, an oxirane ring-containing compound (hereinafter sometimes referred to as “oxirane compound” as appropriate) is a compound containing at least one oxirane ring (oxiranyl group, epoxy group) in the molecule. Specifically, it can be appropriately selected from those usually used as an epoxy resin, and examples thereof include conventionally known aromatic epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins. Any of a monomer, an oligomer, and a polymer may be sufficient. An oxetane ring-containing compound (hereinafter sometimes referred to as “oxetane compound” as appropriate) is a compound containing at least one oxetane ring (oxetanyl group) in the molecule.

Hereinafter, the cationically polymerizable compound applicable to the present invention will be described in detail.
Examples of the cationic polymerizable monomer include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-4006, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and 2001. Epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in each publication such as No. 220526.

  Examples of monofunctional epoxy compounds that can be used in the present invention include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3 -Vinylcyclohexene oxide etc. are mentioned.

Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol. S diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxy 2- (3,4-epoxycyclohexyl) -7,8-epoxy-1,3-dioxaspiro [5.5] undecane, bis (3,4-epoxycyclohexyl) Rumethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, Reserin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,13-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-diepoxyoctane 1,2,5,6-diepoxycyclooctane and the like.
Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  Examples of monofunctional vinyl ethers that can be used in the present invention include, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, Cyclohexylmethyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether Methoxypolyethylene Coal vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, Examples include chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether, and the like.

Examples of polyfunctional vinyl ethers include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, and bisphenol F. Divinyl ethers such as alkylene oxide divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide addition Examples thereof include polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.
As the vinyl ether compound, a di- or trivinyl ether compound is preferable from the viewpoints of curability, adhesion to a recording medium, surface hardness of the formed image, and the like, and a divinyl ether compound is particularly preferable.

  As the oxetane compound in the present invention, known oxetane compounds as described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217 can be arbitrarily selected and used.

  As the oxetane compound that can be used in the present invention, a compound having 1 to 4 oxetane rings in its structure is preferable. By using such a compound, it becomes easy to maintain the viscosity of the liquid for ink-jet recording in a good handling range, and it is possible to obtain high adhesion of the cured ink to the recording medium. it can.

  Examples of monofunctional oxetane compounds used in the present invention include, for example, 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanylmethoxy) Methylbenzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl [benzene, 4-methoxy- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3 -Ethyl-3-oxetanylmethoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl) -3-oxetanylmethyl) ether, 2-ethylhexyl (3- Til-3-oxetanylmethyl) ether, ethyl diethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3- Oxetanylmethyl) ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3-oxe) Nylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, Examples include pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, and the like.

  Examples of polyfunctional oxetane compounds include, for example, 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene) ) Bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether , Triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3 Ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3 -Ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl- 3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3- Til-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentane Kiss (3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, ethylene oxide (EO) modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, Propylene oxide (PO) modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, EO modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) Examples thereof include polyfunctional oxetanes such as ether, PO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, and EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl) ether.

Such oxetane compounds are described in detail in the above-mentioned JP-A No. 2003-341217, paragraphs 0021 to 0084, and the compounds described herein can be suitably used in the present invention.
Among the oxetane compounds used in the present invention, it is preferable to use a compound having 1 to 2 oxetane rings from the viewpoint of viscosity and tackiness of the ink jet recording liquid.

  In the present invention, these cationically polymerizable compounds may be used alone or in combination of two or more.

(Cationic polymerization initiator and photoacid generator)
In the present invention, the coloring liquid contains a cationic polymerization initiator. The cationic polymerization initiator is preferably a compound that generates an acid upon irradiation with radiation (hereinafter also referred to as an acid generator or a photoacid generator). In the present invention, the undercoat liquid contains a photoacid generator.
When the undercoat liquid contains a photoacid generator, an acid is generated in the undercoat liquid by light irradiation, thereby increasing the curability of the coloring liquid and improving the adhesion to the substrate.
The cationic polymerization initiator that can be used in the present invention, preferably a photoacid generator, is a photocationic initiator for photocationic polymerization, or light (400-200 nm ultraviolet light, far ultraviolet light, particularly Preferably, a compound that generates an acid by irradiation with g-line, h-line, i-line, KrF excimer laser light), ArF excimer laser light, electron beam, X-ray, molecular beam, ion beam, or the like is appropriately selected and used. be able to.

  Examples of such a photoacid generator include an onium salt compound such as diazonium salt, phosphonium salt, sulfonium salt, iodonium salt, imide sulfonate, oxime sulfonate, diazodisulfone, disulfone, which decomposes upon irradiation with radiation to generate an acid. Examples thereof include sulfonate compounds such as o-nitrobenzyl sulfonate.

  Examples of other photoacid generators include diazonium salts described in SI Schlesinger, Photogr. Sci. Eng., 18, 387 (1974), TS Bal et al, Polymer, 21, 423 (1980), Ammonium salts described in U.S. Pat. Nos. 4,069,055, 4,069,056, Re 27,992, JP-A-3-140140, DC Necker et al, Macromolecules, 17, 2468 (1984) ), CS Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Patent Nos. 4,069,055, 4,069,056, etc., JV Crivello et al, Macromorecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent Nos. 104,143, 339,049, 410, 201, JP-A-2-150848, JP-A-2-296514, etc.,

  JV Crivello et al, Polymer J. 17, 73 (1985), JV Crivello et al, J. Org. Chem., 43, 3055 (1978), WR Watt et al, J. Polymer Sci., Polymer Chem. Ed. , 22, 1789 (1984), JV Crivello et al, Polymer Bull., 14, 279 (1985), JV Crivello et al, Macromorecules, 14 (5), 1141 (1981), JV Crivello et al, J. Polymer Sci , Polymer Chem. Ed., 17, 2877 (1979), European Patent Nos. 370,693, 161,811, 410,201, 339,049, 233,567, 297, No. 443, No. 297,442, U.S. Pat.Nos. 3,902,114, 4,933,377, 4,760,013, 4,734,444, 2,833,827 And sulfonium salts described in German Patent Nos. 2,904,626, 3,604,580, 3,604,581, JP-A-7-28237, and 8-27102.

  Selenonium salts described in JV Crivello et al, Macromorecules, 10 (6), 1307 (1977), JV Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979), CS Wen et onium salts such as arsonium salts described in al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP JP 48-36281, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62-58241, JP 62 -212401, JP-A 63-70243, JP-A 63-298339 and the like, K. Meier et al, J. Rad. Curing, 13 (4), 26 (1986), TP Gill et al, Inorg. Chem., 19, 3007 (1980), D. Astruc, Acc. Chem. Res., 19 (12), 377 (1986), JP-A-2-161445, etc. Machine metal / organic halide,

  S. Hayase et al, J. Polymer Sci., 25, 753 (1987), E. Reichmanis et al, J. Polymer Sci., Polymer Chem. Ed., 23, 1 (1985), QQ Zhu et al, J Photochem., 36, 85, 39, 317 (1987), B. Amit et al, Tetrahedron Lett., (24) 2205 (1973), DHR Barton et al, J. Chem. Soc., 3571 (1965), PM Collins et al, J. Chem. Soc., Perkin I, 1695 (1975), M. Rudinstein et al, Tetrahedron Lett., (17), 1445 (1975), JW Walker et al, J. Am. Chem. Soc., 110, 7170 (1988), SC Busman et al, J. Imaging Technol., 11 (4), 191 (1985), HM Houlihan et al, Macromolecules, 21, 2001 (1988), PM Collins et al, J. Chem. Soc., Chem. Commun., 532 (1972), S. Hayase et al, Macromolecules, 18, 1799 (1985), E. Reichmanis et al, J. Electrochem. Soc., Solid State Sci. Technol ., 130 (6), FM Houlihan et al, Macromolcules, 21, 2001 (1988), European Patent Nos. 0290,750, 046,083, 156,535, 271,851, 0, 388,343, Polymerization initiators having an O-nitrobenzyl type protecting group described in U.S. Pat.Nos. 3,901,710, 4,181,531, JP-A-60-198538, JP-A-53-133022,

  M. TUNOOKA et al, Polymer Preprints Japan, 35 (8), G. Berner et al, J. Rad. Curing, 13 (4), WJ Mijs et al, Coating Technol., 55 (697), 45 (1983) Akzo H. Adachi et al, Polymer Preprints, Japan, 37 (3), European Patent Nos. 0199,672, 84515, 044,115, 618,564, 0101,122, USA Represented by imino sulfonates described in JP-A Nos. 4,371,605, 4,431,774, JP-A Nos. 64-18143, JP-A Nos. 2-245756, 3-140109, etc. Compounds that generate sulfonic acid upon photolysis, disulfone compounds described in JP-A Nos. 61-166544 and 2-71270, JP-A-3-103854, JP-A-3-103856, and JP-A-4-210960 The diazoketosulfone and diazodisulfone compounds described in the above be able to.

  Further, a group that generates an acid by these lights, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, ME Woodhouse et al, J. Am. Chem. Soc., 104, 5586 (1982), SP Pappas et al, J. Imaging Sci., 30 (5), 218 (1986), S. Kondo et al, Makromol. Chem., Rapid Commun., 9, 625 (1988), Y. Yamada et al, Makromol Chem., 152, 153, 163 (1972), JV Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 3845 (1979), US Pat. No. 3,849,137, German patent 3,914,407, JP 63-26653, JP 55-164824, JP 62-69263, JP 63-1446038, JP 63-163452, JP The compounds described in JP-A-62-153853 and JP-A-63-146029 can be used. For example, diazonium salt, ammonium salt, phosphonium salt, iodonium salt, sulfonium salt, selenonium salt, onium salt such as arsonium salt, organic halogen compound, organic metal / organic halide, polymerization initiator having o-nitrobenzyl type protecting group And compounds capable of generating a sulfonic acid by photolysis, such as iminosulfonate, disulfone compounds, diazoketosulfones, and diazodisulfone compounds.

  Furthermore, VNR Pillai, Synthesis, (1), 1 (1980), A. Abad et al, Tetrahedron Lett., (47) 4555 (1971), DHR Barton et al, J. Chem. Soc., (C), 329 (1970), US Pat. No. 3,779,778, European Patent 126,712, and the like, compounds that generate an acid by light can also be used.

  Preferred examples of the photoacid generator that can be used in the present invention include compounds represented by the following formulas (b1), (b2), and (b3).

In the formula (b1), R ²⁰¹ , R ²⁰² and R ²⁰³ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably a sulfonate anion, a carboxylate anion, a bis (alkylsulfonyl) amide anion, a tris (alkylsulfonyl) methide anion, BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ or the following The organic anion which has a carbon atom is preferable.

  Preferable organic anions include organic anions represented by the following formula.

Rc ¹ represents an organic group.
Examples of the organic group in Rc ¹ include those having 1 to 30 carbon atoms, and preferably an alkyl group, a cycloalkyl group, an aryl group, or a plurality of these are a single bond, —O—, —CO ₂ —, —S—. , —SO ₃ —, —SO ₂ N (Rd ¹ ) — and the like.
Rd ¹ represents a hydrogen atom or an alkyl group.
Rc ³ , Rc ⁴ and Rc ⁵ each independently represents an organic group.
Preferred examples of the organic group for Rc ³ , Rc ⁴ , and Rc ⁵ include the same organic groups as those for Rc ¹ , and most preferably a perfluoroalkyl group having 1 to 4 carbon atoms.
Rc ³ and Rc ⁴ may combine to form a ring.
Examples of the group formed by combining Rc ³ and Rc ⁴ include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group.
As the organic group of Rc ¹ and Rc ^{3 to} Rc ⁵ , the most preferred is an alkyl group substituted at the 1-position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved.

The carbon number of the organic group as R ²⁰¹ , R ²⁰² and R ²⁰³ is generally 1-30, preferably 1-20.
Two of R ^{201 to} R ²⁰³ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ²⁰¹ to R ^203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Specific examples of the organic group as R ²⁰¹ , R ²⁰² and R ²⁰³ include corresponding groups in the compounds (b1-1), (b1-2) and (b1-3) described later.

In addition, the compound which has two or more structures represented by Formula (b1) may be sufficient. For example, at least one of R ²⁰¹ to R ²⁰³ of a compound represented by the formula (b1) is at least one directly with R ²⁰¹ to R ²⁰³ of another compound represented by formula (b1), or a linking group It may be a compound having a structure bonded via

More preferred components (b1) include compounds (b1-1), (b1-2), and (b1-3) described below.
Compound (b1-1) is in which at least one aryl group R ²⁰¹ to R ²⁰³ in formula (b1), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
In the arylsulfonium compound, all of R ^{201 to} R ²⁰³ may be an aryl group, or a part of R ^{201 to} R ²⁰³ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.
Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, aryldicycloalkylsulfonium compounds, and the like.
The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, and more preferably a phenyl group or an indole residue. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

As the alkyl group that the arylsulfonium compound has as necessary, a linear or branched alkyl group having 1 to 15 carbon atoms is preferable. For example, a methyl group, an ethyl group, a propyl group, an n-butyl group, sec -A butyl group, a t-butyl group, etc. can be mentioned.
The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

Aryl group, alkyl group of R ²⁰¹ to R ^203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, and most preferred. Is an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms. Substituents, of the three R ²⁰¹ to R ^203, may be substituted on any one, or may be substituted on all of three. When R ^{201 to} R ²⁰³ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (b1-2) will be described.
The compound (b1-2) is a compound in the case where R ^{201 to} R ²⁰³ in the formula (b1) each independently represents an organic group not containing an aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group having no aromatic ring as R ²⁰¹ to R ²⁰³ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R ²⁰¹ to R ²⁰³ each independently, preferably an alkyl group, a cycloalkyl group, an allyl group, a vinyl group, more preferably a linear, branched or cyclic 2-oxoalkyl group, an alkoxycarbonylmethyl group, particularly preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R ²⁰¹ to R ²⁰³ may be linear, it may be either branched, preferably a straight-chain or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, a butyl group, a pentyl group), and a linear, branched 2-oxoalkyl group, and an alkoxycarbonylmethyl group are more preferable.
The cycloalkyl group as R ²⁰¹ to R ²⁰³ is preferably a cycloalkyl group having 3 to 10 carbon atoms (a cyclopentyl group, a cyclohexyl group, a norbornyl group) can be exemplified, more preferably a cyclic 2-oxoalkyl group.
Linear R ²⁰¹ to R ^203, branched, or cyclic 2-oxoalkyl group, preferably, may be mentioned 2-position group having> C = O at the above-described alkyl or cycloalkyl group.
The alkoxy group in the alkoxycarbonylmethyl group as R ²⁰¹ to R ^203, preferably may be mentioned alkoxy groups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group).
R ^{201 to} R ²⁰³ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  The compound (b1-3) is a compound represented by the following formula (b1-3) and is a compound having a phenacylsulfonium salt structure.

In formula (b1-3), R ^{1c to} R ^5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom.
R ^6c and R ^7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
R ^x and R ^y each independently represents an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group.
Any two or more of R ^{1c to} R ^5c , R ^6c and R ^7c , and R ^x and R ^y may be bonded to each other to form a ring structure.
Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ⁻ in formula (b1).

The alkyl group as R ^{1c to} R ^7c may be either linear or branched, for example, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms (for example, Methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group).
Preferred examples of the cycloalkyl group represented by R ^{1c to} R ^7c include a cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group and a cyclohexyl group).
The alkoxy group as R ^{1c to} R ^{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Examples of the group formed by combining any two or more of R ^{1c to} R ^5c , R ^6c and R ^7c , and R ^x and R ^y include a butylene group and a pentylene group. This ring structure may contain an oxygen atom, a sulfur atom, an ester bond, or an amide bond.

Preferably any one of R ^{1c to} R ^5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R ^1c to R ^5c is 2-15. This is preferable because solvent solubility is further improved and generation of particles is suppressed during storage.

^Examples of the alkyl group and cycloalkyl group as R ^x and R ^y include the same alkyl groups and cycloalkyl groups as R ^{1c to} R ^7c .
R ^x and R ^y are preferably a 2-oxoalkyl group or an alkoxycarbonylmethyl group.
Examples of the 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R ^{1c to} R ^5c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R ^{1c to} R ^5c .
R ^x and R ^y are preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more alkyl groups or cycloalkyl groups.

Formula (b2), in (b3), R ²⁰⁴ ~R ²⁰⁷ each independently represents an aryl group, an alkyl group or a cycloalkyl group. X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ⁻ in formula (b1).
Phenyl group and a naphthyl group are preferred as the aryl group of R ²⁰⁴ to R ^207, more preferably a phenyl group.
The alkyl group as R ²⁰⁴ to R ²⁰⁷ may be linear, it may be either branched, preferably a straight-chain or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group). The cycloalkyl group as R ²⁰⁴ to R ²⁰⁷ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
The R ²⁰⁴ to R ²⁰⁷ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.

  Examples of the compound that generates an acid upon irradiation with actinic rays or radiation that may be used further include compounds represented by the following formulas (b4), (b5), and (b6).

In formulas (b4) to (b6), Ar ³ and Ar ⁴ each independently represents an aryl group.
R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ each independently represents an alkyl group, a cycloalkyl group or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.

Preferable examples of the photoacid generator include compounds represented by formulas (b1) to (b3).
Although the preferable compound example [(b-1)-(b-96)] of the photo-acid generator which can be used for this invention is given below, this invention is not limited to these.

Further, oxazole derivatives and s-triazine derivatives described in JP-A No. 2002-122994, paragraph numbers [0029] to [0030] are also preferably used.
The onium salt compounds and sulfonate compounds exemplified in JP-A-2002-122994, paragraphs [0037] to [0063] can also be suitably used in the present invention.

  A photo-acid generator and a cationic polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

(Coloring agent)
In the present invention, the coloring liquid contains at least a coloring agent. On the other hand, the undercoat liquid may contain a colorant, but preferably contains substantially no colorant or contains a white pigment.
There is no restriction | limiting in particular in the coloring agent which can be used in this invention, According to a use, well-known various pigments and dyes can be selected suitably and can be used. Among them, the colorant contained in the coloring liquid is preferably a pigment from the viewpoint of excellent light resistance.

The pigment preferably used in the present invention will be described.
The pigment is not particularly limited, and all commercially available organic pigments and inorganic pigments, and those obtained by dyeing resin particles with a dye can be used. Furthermore, commercially available pigment dispersions and surface-treated pigments, for example, pigments dispersed in an insoluble resin or the like as a dispersion medium, or those obtained by grafting a resin on the pigment surface, etc., impair the effects of the present invention. It can be used as long as it is not.
Examples of these pigments include, for example, “Dictionary of Pigments” edited by Seijiro Ito (2000), W. Herbst, K. Hunger, Industrial Organic Pigments, JP 2002-12607 A, JP 2002-188025 A, Examples thereof include pigments described in JP2003-26978A and JP2003-342503A.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include 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. Pigment yellow 180, C.I. I. Non-benzidine type azo pigments such as C.I. Pigment Yellow 200 (Novoperm Yellow 2HG); I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); 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.).

  C. As a thing which exhibits red or magenta color, 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, CINQUASIA Magenta RT-355T; manufactured by Ciba Specialty Chemicals), 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.).

As a pigment exhibiting blue or cyan, C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Pigment blue 15, C.I. I. Phthalocyanine pigments such as CI Pigment Blue 15: 3 (IRGALITE BLE GLO; manufactured by Ciba Specialty Chemicals) (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).
As a pigment exhibiting green, 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).
As a pigment exhibiting an orange color, 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 the black pigment include carbon black, titanium black, and aniline black. Examples of the carbon black include SPECIAL BLACK 250 (manufactured by Degussa).
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.

Dispersing colorants, for example, bead mill, 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 be used.
When dispersing the colorant, a dispersant such as a surfactant can be added.
Moreover, when adding a coloring agent, it is also possible to use the synergist according to various coloring agents as a dispersing aid as needed. The dispersion aid is preferably added in an amount of 1 to 50 parts by weight with respect to 100 parts by weight of the colorant.

  As a dispersion medium for various components such as a colorant in the coloring liquid, a solvent may be added, or the polymerizable compound which is a low molecular weight component without solvent may be used as the dispersion medium. Is preferably an active energy ray-curable liquid, and is preferably solvent-free in order to cure after applying the coloring liquid onto the recording medium. This is because if the solvent remains in the image formed from the cured coloring liquid, the solvent resistance is deteriorated or a problem of VOC (Volatile Organic Compound) of the remaining solvent occurs. From such a point of view, a polymerizable compound is used as the dispersion medium, and among them, it is preferable to select a polymerizable compound having the lowest viscosity from the viewpoints of dispersion suitability and improved handling of the colored liquid.

The average particle size of the colorant used here is preferably 0.01 μm or more and 0.4 μm or less, and more preferably 0.02 μm or more and 0.2 μm or less, because the finer the particle size, the better the color developability. It is preferable to set the colorant, dispersant, dispersion medium, dispersion conditions, and filtration conditions so that the maximum particle diameter is 3 μm or less, preferably 1 μm or less. By controlling the particle size, clogging of the head nozzle can be suppressed, and the storage stability of the coloring liquid, the transparency of the coloring liquid, and the curing sensitivity can be maintained. In the present invention, by using the dispersant having excellent dispersibility and stability, a uniform and stable dispersion can be obtained even when a fine particle colorant is used.
The particle diameter of the colorant in the coloring liquid can be measured by a known measurement method. Specifically, it can be measured by a centrifugal sedimentation light transmission method, an X-ray transmission method, a laser diffraction / scattering method, and a dynamic light scattering method. In the present invention, a value obtained by measurement using a laser diffraction / scattering method is employed.

(Sensitizer)
A sensitizer may be added to the coloring liquid and the undercoat liquid in the present invention in order to absorb specific actinic radiation and promote decomposition of the polymerization initiator. The sensitizer absorbs specific actinic radiation and enters an electronically excited state. The sensitizer in an electronically excited state comes into contact with the polymerization initiator, and effects such as electron transfer, energy transfer, and heat generation occur. As a result, the polymerization initiator undergoes a chemical change and decomposes to generate radicals, acids or bases.
As a sensitizer that can be used in the present invention, a sensitizing dye is preferable.
Examples of preferred sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.
Polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine), merocyanines ( For example, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squalium (eg, squalium) ), Coumarins (eg 7-diethylamino-4-methylcoumarin).

  More preferable examples of the sensitizing dye include compounds represented by the following formulas (IX) to (XIII).

In the formula (IX), A ¹ represents a sulfur atom or NR ⁵⁰ , R ⁵⁰ represents an alkyl group or an aryl group, and L ² forms a basic nucleus of the dye together with the adjacent A ¹ and the adjacent carbon atom. R ⁵¹ and R ⁵² each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁵¹ and R ⁵² may be bonded to each other to form an acidic nucleus of the dye. Good. W represents an oxygen atom or a sulfur atom.

In formula (X), Ar ¹ and Ar ² each independently represent an aryl group and are linked via a bond with —L ³ —. Here, L ³ represents —O— or —S—. W is synonymous with that shown in Formula (IX).

In the formula (XI), A ₂ represents a sulfur atom or NR ⁵⁹ , L ⁴ represents a nonmetallic atomic group that forms a basic nucleus of the dye together with adjacent A ₂ and a carbon atom, R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ and R ⁵⁸ each independently represent a monovalent nonmetallic atomic group, and R ⁵⁹ represents an alkyl group or an aryl group.

In formula (XII), A ³ and A ⁴ each independently represent —S—, —NR ⁶² — or —NR ⁶³ —, wherein R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted alkyl group, substituted or represents an unsubstituted aryl group, L to ^5, L ⁶ are each independently, together with the adjacent a ^3, a ⁴ and adjacent carbon atoms represents a nonmetallic atom group necessary for forming a basic nucleus of a dye, R ⁶⁰ , R ⁶¹ each independently represents a hydrogen atom or a monovalent non-metallic atomic group, or may be bonded to each other to form an aliphatic or aromatic ring.

In the formula (XIII), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent, and A ⁵ represents an oxygen atom, a sulfur atom or ═NR ⁶⁷ . R ⁶⁴ , R ⁶⁵ and R ⁶⁷ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ each represent an aliphatic or aromatic ring. Can be combined to form.

  Preferable specific examples of the compounds represented by formulas (IX) to (XIII) include (E-1) to (E-20) shown below. In the following specific examples, Ph represents a phenyl group, and Me represents a methyl group.

When a sensitizer is used in the color liquid, the concentration of the sensitizer added is preferably 0.1 to 15.0% by weight based on the total weight of the color liquid, It is more preferably 0.0% by weight, and even more preferably 1.0 to 8.0% by weight. When the addition amount is within the above range, good curability inside the film can be obtained.
When a sensitizer is used in the undercoat liquid, the addition concentration of the sensitizer is preferably 0.1 to 15.0% by weight, more preferably 0.8%, based on the total weight of the undercoat liquid. It is 5 to 10.0% by weight, more preferably 1.0 to 8.0% by weight. When the addition amount is within the above range, good curability inside the film can be obtained.

(Surfactant)
The coloring liquid and the undercoat liquid preferably contain a surfactant, and examples of the surfactant used in the present invention include the following surfactants. Examples thereof include those described in JP-A Nos. 62-173463 and 62-183457. Specifically, for example, anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene -Nonionic surfactants such as polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. An organic fluoro compound may be used as the known surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compounds include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826.
In particular, the surfactant used in the present invention is not limited to the above-described surfactant, and may be any additive capable of efficiently reducing the surface tension with respect to the added concentration.

(Radically polymerizable compound)
The radical polymerizable compound that can be used in the undercoat liquid will be described.
As the polymerizable compound, various (meth) acrylate monomers can be preferably used.
For example, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isoamyl stil acrylate, isostearyl acrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, Butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, -Hydroxy-3-phenoxypropyl acrylate, 2-acryloxyethyl succinic acid, 2-acryloxyethyl phthalic acid, 2-acryloxyethyl-2-hydroxyethyl-phthalic acid, lactone-modified flexible acrylate, t -A monofunctional monomer such as butylcyclohexyl acrylate.

  Also, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexane Diol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, EO (ethylene oxide) adduct of bisphenol A, PO (propylene oxide) adduct of bisphenol A Diacrylate, hydroxypivalic acid neopentyl glycol diacrylate, polytetramethylene glycol diacrylate Rate, trimethylolpropane triacrylate, EO modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, glycerin propoxytriacrylate, caprolactone modified trimethylolpropane triacrylate And polyfunctional monomers such as pentaerythritol ethoxytetraacrylate and caprolactone-modified dipentaerythritol hexaacrylate.

  In addition, polymerizable oligomers can be blended in the same manner as the monomer. Examples of the polymerizable oligomer include epoxy acrylate, aliphatic urethane acrylate, aromatic urethane acrylate, polyester acrylate, and linear acrylic oligomer.

  As the radically polymerizable compound that can constitute the undercoat liquid, the radically polymerizable compounds listed above can be used as appropriate, but from the viewpoint of improving the flexibility and abrasion resistance of the cured product, the radically polymerizable compound can be used. Is preferably a monofunctional cyclic acrylate, and more preferably any one of the following compounds (M-1 to M-29).

(Radical polymerization initiator)
Preferred radical polymerization initiators that can be used in the present invention include (a) aromatic ketones, (b) aromatic onium salt compounds, (c) organic peroxides, (d) thio compounds, (e) hexaarylbiphenyls. An imidazole compound, (f) a ketoxime ester compound, (g) a borate compound, (h) an azinium compound, (i) a metallocene compound, (j) an active ester compound, (k) a compound having a carbon halogen bond, and (l) Examples thereof include alkylamine compounds. These radical polymerization initiators may be used alone or in combination with the above compounds (a) to (l). The radical polymerization initiator in the present invention is preferably used alone or in combination of two or more.

(Other additives)
In the coloring liquid and undercoat liquid in the present invention, in addition to the polymerizable compound and the polymerization initiator, various additives can be used in combination according to the purpose. For example, an ultraviolet absorbent can be used from the viewpoint of improving the weather resistance of the obtained image. Further, an antioxidant can be added to improve the stability of the coloring liquid and the undercoat liquid.
In addition, various organic and metal complex anti-fading agents, conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride for the purpose of controlling ejection stability, and adhesion to substrates In order to improve the property, a trace amount of organic solvent can be added.
Moreover, various polymer compounds can be added to adjust film physical properties. High molecular compounds include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenol resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellacs, vinyl resins, acrylic resins. Rubber resins, waxes and other natural resins can be used. Two or more of these may be used in combination.
In addition to this, if necessary, for example, leveling additives, matting agents, waxes for adjusting film physical properties, tackifiers that do not inhibit polymerization in order to improve adhesion to polyolefins, PET, etc. Can be contained.

(Relationship between surface tension of coloring liquid and undercoat liquid)
From the viewpoint of preventing bleeding of the formed image for a long time until the coloring liquid applied on the recording medium is started, the surface tension of the coloring liquid is γA, and the surface tension of the undercoat liquid is γB. The relationship between γA and γB preferably satisfies γA> γB, more preferably satisfies γA−γB ≧ 1, and particularly preferably satisfies γA−γB ≧ 2.
The surface tension is a value measured at a liquid temperature of 25 ° C. by the Wilhelmy method using a commonly used surface tension meter (for example, surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.). is there.

(2) Inkjet recording method In the inkjet recording method of the present invention, an ink set composed of a colored liquid for forming an image and an undercoat liquid used as an undercoat liquid is used.
The recording method includes an undercoat liquid applying step for applying an undercoat liquid onto a recording medium, a light irradiation step for generating an acid by irradiating the undercoat liquid with light, and an image obtained by discharging a colored liquid onto the undercoat liquid. It is preferable to include an image forming process for forming and a complete curing process for completely curing the undercoat liquid and the coloring liquid. In the light irradiation step, the acid is generated from the photoacid generator contained in the undercoat liquid, and the color liquid is discharged onto the undercoat liquid, whereby the curability of the color liquid is improved.
When the undercoat liquid contains a photoacid generator and a cationically polymerizable compound, and when the undercoat liquid contains a photoacid generator, a radical polymerizable compound, and a radical polymerization initiator, the undercoat liquid was applied on the recording medium. Thereafter, it is preferable to include a step of semi-curing the undercoat liquid before applying the coloring liquid. The step of semi-curing is preferably a step of semi-curing the undercoat liquid by a light irradiation step. In addition, although a semi-hardening process and a light irradiation process can also be performed in a separate process, it is preferable to semi-harden an undercoat liquid by a light irradiation process.
That is, in the present invention, the inkjet recording method includes an undercoat liquid applying step for applying an undercoat liquid onto a recording medium, an image forming step for forming an image by discharging a colored liquid onto the undercoat liquid, and the undercoat liquid. And a complete curing step for completely curing the coloring liquid, and preferably having an undercoat liquid semi-curing step for semi-curing the undercoat liquid before the image forming step.
Therefore, in the present invention, the inkjet recording method is
(I) an undercoat liquid applying step for applying an undercoat liquid onto a recording medium;
(Ii) an undercoat liquid semi-curing step for semi-curing the undercoat liquid;
(Iii) an image forming step of discharging the colored liquid onto the semi-cured undercoat liquid to form an image;
(Iv) a complete curing step of completely curing the undercoat liquid and the coloring liquid,
As the ink set containing the undercoat liquid and the coloring liquid, it is particularly preferable to use the ink set for inkjet recording of the present invention.

  Moreover, it is preferable that the colored liquid in the present invention uses a plurality of colored liquids as a multicolor ink set. Thus, when using a multicolor ink set, the inkjet recording method of the present invention may include a step of semi-curing the applied color liquid after the color liquid is applied to the recording medium. It is preferable to include a step of applying the latter half curing. For example, when forming a secondary color using the coloring liquid A and the coloring liquid B having different hues, the coloring liquid A and the coloring liquid B can be discharged continuously, or after the coloring liquid A is discharged. It is also possible to perform a step of semi-curing the colored liquid A, and then to discharge the colored liquid B onto the semi-cured colored liquid A.

Further, from the viewpoint of controlling the cured state of the image, in the step of semi-curing the undercoat liquid and / or the step of completely curing the image, the humidity of the region where the undercoat liquid is semi-cured and / or the region where the image is completely cured. It is preferable to control this.
From the viewpoint of obtaining a preferable semi-cured state, the preferable humidity in the region where the undercoat liquid is semi-cured is preferably 40% or more and 80% or less, and the relative humidity in the air is 50% or more and 70%. It is more preferable that the relative humidity in air is 55% or more and 65% or less. A preferable semi-cured state will be described later.
From the viewpoint of improving the curability of the image, it is preferable that the relative humidity in the region where the image is completely cured is 50% or less, and the relative humidity in the air is 40% or less. More preferably, the relative humidity in the air is particularly preferably 30% or less.
The means for controlling the humidity is not particularly limited, and a commercially available humidifier or dehumidifier can be used. From the viewpoint of space saving of the apparatus and ease of control, it is preferable to use a commercially available air conditioning unit. Examples of commercially available air conditioning units include the precision air conditioning unit (temperature / humidity control unit) manufactured by Apiste PAU series (PAU-300S-HC, PAU-A920S-HC, PAU-A1400S-HC, PAU-A2600S-HC, PAU-A3500S-HC).

FIG. 1 shows a conceptual diagram of an ink jet recording method that can be suitably used in the present invention. This will be described in detail below with reference to FIG.
The recording medium 6 is conveyed by recording medium conveying means 7A and 7B, and is conveyed from left to right in FIG.
The recording medium and the recording medium conveying means are not particularly limited, but in the present embodiment shown in FIG. 1, a plastic film is used as the recording medium, and the film unwinding as the recording medium conveying means. Machine (7A) and film winder (7B) are used.
In the first step, the undercoat liquid is applied onto the recording medium 6 by means 1 for applying the undercoat liquid. Examples of means for applying the undercoat liquid include a roll coater. In FIG. 1, the undercoat liquid contains a photoacid generator and a cationically polymerizable compound.
Subsequently, in the second step, the undercoat liquid applied on the recording medium 6 is semi-cured by means 2 for semi-curing the undercoat liquid. An example of means for semi-curing the undercoat liquid is an ultraviolet light source. Here, the relative humidity in the air in the semi-cured region is adjusted to 55% or more and 65% or less by the precision air conditioning unit.
In the third step, a colored image is formed by means 3C for applying a colored liquid onto the film of the undercoat liquid semi-cured on the recording medium 6. In FIG. 1, a cyan coloring liquid is applied to form a cyan image. Examples of the means 3C for applying the cyan coloring liquid include a cyan ink jet recording head. In the fourth step, the cyan colored liquid is semi-cured by means 4C for semi-curing the colored liquid applied in the third process. In FIG. 1, an ultraviolet light source is used as a means for semi-curing the colored liquid, and the cyan colored liquid applied on the film of the undercoat liquid is semi-cured.
In the fifth step, a magenta color liquid is applied by means 3M for applying a magenta color liquid onto the film of the undercoat and / or cyan color liquid semi-cured on the recording medium to form a magenta image. As the means 3M for applying the magenta coloring liquid, a magenta inkjet recording head can be exemplified. In the sixth step, the colored liquid applied in the fifth step is semi-cured. In FIG. 1, an ultraviolet light source is used as means 4M for semi-curing the magenta colored liquid, and the magenta colored liquid applied on the undercoat liquid and / or cyan colored liquid film is semi-cured.
Similarly, in the seventh step, after the yellow image is formed on any one of the undercoat liquid, cyan color liquid, and magenta color liquid by means 3Y for applying the yellow color liquid, the yellow color is formed in the eighth process. The applied yellow coloring liquid is semi-cured by means 4Y for semi-curing the liquid.
Further, in the ninth step, a black image is formed by means 3K for applying a black color liquid onto any one of the undercoat liquid, cyan color liquid, magenta color liquid and yellow color liquid. In the tenth step, the black colored liquid is semi-cured by means 4K for semi-curing the black colored liquid.
Subsequently, in the eleventh step, the formed full-color image is completely cured by means 5 for completely curing the formed full-color image. Here, the relative humidity in the air in the region where the image is completely cured is adjusted to 30% or less by the precision air conditioning unit.
Here, the tenth step can be omitted, and in this case, the recording medium to which the last colored liquid is applied is completely cured without going through a semi-curing step.
Moreover, after forming an image with a colored liquid, a method known to those skilled in the art may be appropriately performed, such as discharging or applying an undercoat liquid as an overcoat layer.

<Step of applying undercoat liquid on recording medium>
In the step of applying the undercoat liquid onto the recording medium, the undercoat liquid is applied to the same area as the image formed by discharging the colored liquid droplets on the recording medium or an area wider than the image. Is preferred.
Further, the application amount of the undercoat liquid (weight ratio per unit area) is preferably in the range of 0.05 to 5 when the maximum application amount of the coloring liquid (per color) is 1. The range of 0.07 to 4 is more preferable, and the range of 0.1 to 3 is particularly preferable.

In the inkjet recording method of the present invention, a coating device, an inkjet nozzle, or the like can be used as means for applying the undercoat liquid on the recording medium.
The coating apparatus is not particularly limited and can be appropriately selected from known coating apparatuses according to the purpose, for example, an air doctor coater, a blade coater, a lot coater, a knife coater, a squeeze coater, and an 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”.
Among them, from the viewpoint of apparatus cost, the application of the undercoat liquid onto the recording medium is preferably performed by coating using a relatively inexpensive bar coater or spin coater, or by the ink jet method.

<Step of applying a colored liquid onto the recording medium>
In the present invention, the colored liquid discharged onto the film of the semi-cured undercoat liquid and / or colored liquid on the recording medium has a droplet size of 0.1 pL (picoliter; the same applies hereinafter) to 100 pL ( It is preferable that droplets are ejected (preferably by an ink jet nozzle). When the droplet size is within the above range, it is effective in that an image with high sharpness can be drawn at a high density. More preferably, it is 0.5 pL or more and 50 pL or less.
Further, the maximum amount of the coloring liquid applied on the recording medium can be arbitrarily selected depending on the concentration of the coloring agent contained in the coloring liquid, but from the viewpoint of color reproducibility, curability, and image surface smoothness. from preferably 0.01 g / cm ² or more 0.200 g / cm ² or less, 0.02 g / cm ² or more 0.150 g / cm ² or less are preferred, 0.03 g / cm ² or more 0.100 g / cm ² or less Is particularly preferred.
Note that “on the recording medium” may be an upper part of the recording medium and does not necessarily need to be in contact with the recording medium.
It is preferable that the droplet ejection interval until the colored droplets are ejected after application of the undercoat liquid is in the range of 5 μs or more and 10 seconds or less. When the droplet ejection interval is within the above range, it is effective in that the effect of the present invention can be remarkably exhibited. The interval between the colored droplets is more preferably 10 μs to 5 seconds, and particularly preferably 20 μs to 5 seconds.

  The means for applying the coloring liquid is not particularly limited, but an inkjet head is preferably used. As an inkjet head, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses vibration pressure of a piezo element, an electric signal is converted into an acoustic beam, and ink is used. A head of an acoustic ink jet method in which ink is ejected by using radiation pressure by irradiating the ink, or a thermal ink jet (bubble jet (registered trademark)) method in which ink is heated to form bubbles and the generated pressure is used is suitable. It is.

<Step of semi-curing undercoat liquid and step of curing colored liquid>
In the present invention, “semi-cured” means partially cured (partially cured), and is a state in which the undercoat liquid and / or the colored liquid is partially cured but not completely cured. Say. When the undercoat liquid applied on the recording medium (base material) or the colored liquid discharged onto the undercoat liquid is semi-cured, the degree of curing may be uneven. For example, it is preferable that the undercoating liquid and / or the coloring liquid is hardened in the depth direction.

  As a method of semi-curing the undercoat liquid and / or the colored liquid, (1) a basic compound is imparted to the acidic polymer, or an acidic compound or a metal compound is imparted to the basic polymer. A method using an agglomeration phenomenon, (2) an undercoat liquid and / or a colored liquid is prepared in advance to have a high viscosity, and a low boiling point organic solvent is added thereto to reduce the viscosity, and the low boiling point organic solvent is evaporated to obtain the original liquid (3) A method of returning to the original high viscosity by heating and cooling the undercoat liquid and / or coloring liquid prepared to a high viscosity, and (4) an undercoating liquid and / or coloring liquid. Examples include a known thickening method such as a method in which an active energy ray or heat is applied to cause a curing reaction. Among these, (4) a method of causing the curing reaction by applying active energy rays or heat to the undercoat liquid and / or coloring liquid is preferable, and a method of causing the curing reaction by irradiation (light irradiation) of active energy rays is particularly preferable. .

  The method of causing an active energy ray or heat to cause a semi-curing reaction is a method in which the polymerization reaction of the polymerizable compound on the surface of the undercoat liquid and / or the colored liquid applied to the recording medium is insufficiently performed.

  When polymerizing a radically polymerizable undercoat liquid in an atmosphere containing a large amount of oxygen, such as in the air or partially substituted with an inert gas, in order to suppress the radical polymerization of oxygen, There is a tendency that radical polymerization is inhibited on the surface of the undercoat liquid layer applied to. As a result, the semi-curing becomes non-uniform, the curing proceeds more inside the undercoat liquid layer, and the surface curing tends to be delayed. Here, the undercoat liquid layer is a layer of the undercoat liquid applied on the substrate.

  Even when the cationic polymerizable undercoat liquid or colored liquid is polymerized in an atmosphere having moisture, the undercoat liquid layer or colored liquid droplets applied on the recording medium because of the action of inhibiting the cationic polymerization of moisture. Curing progresses more inside and tends to delay the curing of the surface.

  Among these, semi-curing by irradiation with active energy rays is preferable. As the active energy ray, α ray, γ ray, electron beam, X ray, ultraviolet ray, visible light, infrared ray or the like can be used. Among these, ultraviolet rays or visible light is preferable, and ultraviolet rays are more preferable. Further, the peak wavelength of the active radiation depends on the absorption characteristics of the sensitizing dye, but is preferably 200 to 600 nm, more preferably 300 to 450 nm, and further preferably 350 to 420 nm, for example. .

The amount of energy required for the semi-curing of the undercoat liquid and / or the coloring liquid varies depending on the type and content of the polymerization initiator, but when energy is applied by active energy rays, it is about 1 to 500 mJ / cm ^2. preferable. In addition, when energy is applied by heating, it is preferable to heat for 0.1 to 1 second under the condition that the surface temperature of the recording medium is in a temperature range of 40 to 80 ° C.

Generation of active species due to decomposition of the polymerization initiator is promoted by application of active energy rays such as actinic light and heating, or heat, and polymerizability or cross-linkability caused by the active species is increased by increasing the active species or increasing the temperature. The curing reaction by polymerization or crosslinking of the material is accelerated.
Moreover, thickening (viscosity increase) can also be suitably performed by irradiation of actinic light or heating.

  When a colored liquid is ejected onto the semi-cured undercoat liquid, or a different colored liquid (especially a colored liquid having a different hue) is ejected onto the semi-cured colored liquid, it is obtained. Which has a positive technical effect on the quality of the printed material produced. Moreover, the action mechanism can be confirmed by observing the cross section of the printed matter.

A portion (high concentration portion) ejected at a high density when about 12 pL of colored liquid is deposited on a semi-cured undercoat liquid having a thickness of about 5 μm provided on the substrate. This will be described as an example.
FIG. 2 is a schematic cross-sectional view showing an embodiment of a printed matter obtained by depositing a colored liquid on a semi-cured undercoat liquid layer. At the time of manufacturing the printed matter of FIG. 2, the undercoat liquid is semi-cured, and the curing on the base material 16 side is proceeding more than the surface layer. FIG. 2 shows an undercoat layer 14 in which a coloring liquid is applied to a semi-cured undercoat liquid layer.
In this case, the following three features are observed in the cross section of the obtained image 10.
(1) A part of the colored liquid cured product 12 appears on the surface.
(2) A part of the colored liquid cured product 12 is embedded in the undercoat layer 14, and
(3) An undercoat layer 14 exists between the lower side of the colored liquid cured product 12 and the substrate 16.
That is, the printed matter obtained by applying the colored liquid onto the semi-cured undercoat liquid layer has a cross section as schematically shown in FIG. When the above conditions (1), (2), and (3) are satisfied, it can be said that the colored liquid is applied to the semi-cured undercoat liquid. In this case, the droplets of the colored liquid ejected with high density are connected to each other to form a colored film, which gives a uniform and high color density. The undercoat layer means a layer obtained by curing the undercoat liquid layer.

3 and 4 are schematic cross-sectional views showing one embodiment of a printed matter obtained by depositing a colored liquid on an uncured undercoat liquid layer. 3 and 4 show the undercoat layer 18 in which a colored liquid is applied to the uncured undercoat liquid layer.
When the colored liquid is ejected onto the uncured undercoat liquid layer, all of the colored liquid enters the undercoat liquid layer and / or the undercoat liquid does not exist below the colored liquid. Specifically, in FIG. 3, in the cross section of the image 10 to be obtained, the colored liquid cured product 12 is completely submerged in the undercoat layer 18, and a part of the colored liquid cured product 12 does not appear on the surface. . Further, as shown in FIG. 4, in the cross section of the obtained image 10, the undercoat layer 18 does not exist below the colored liquid cured product 12.
In this case, even if the coloring liquid is applied at a high density, the droplets are independent of each other, which causes a decrease in color density.

FIG. 5 is a schematic cross-sectional view showing one embodiment of a printed matter obtained by depositing a colored liquid onto a completely cured undercoat liquid layer. FIG. 5 shows the undercoat layer 20 in which a colored liquid is applied to the fully cured undercoat liquid layer.
When the colored liquid is ejected onto the completely cured undercoat liquid layer, the colored liquid does not enter the undercoat liquid layer. Specifically, as shown in FIG. 5, the colored liquid cured product 12 does not sink into the undercoat layer 20.
Such a state causes the occurrence of droplet ejection interference, a uniform colored liquid film layer cannot be formed, and the color reproducibility is lowered.

From the viewpoint of forming a uniform colored liquid liquid layer (colored film) and preventing the occurrence of droplet ejection interference without the liquid droplets becoming independent when the colored liquid droplets are applied at high density, The transfer amount of the undercoat liquid per unit area is preferably sufficiently smaller than the maximum droplet amount of the coloring liquid applied per unit area. That is, if the transfer amount (weight) per unit area of the undercoat liquid layer is M (undercoat liquid) and the maximum weight of the colored liquid applied per unit area is m (colored liquid), M (undercoat liquid), m The (coloring liquid) preferably satisfies the following relationship.
[M (colored liquid) / 30] ≦ [M (undercoat liquid)] ≦ [m (colored liquid)]
Further, it is more preferable that [m (colored liquid) / 10] ≦ [M (undercoat liquid)] ≦ [m (colored liquid) / 3], and [m (colored liquid) / 10] ≦ [M (undercoat). Liquid)] ≦ [m (colored liquid) / 5]. Here, the maximum weight of the coloring liquid applied per unit area is the maximum weight per color.
It is preferable that [m (colored liquid) / 30] ≦ [M (undercoat liquid)] because the occurrence of droplet ejection interference can be suppressed and the dot size reproducibility is excellent. Further, it is preferable that M (undercoat liquid) ≦ m (colored liquid) because a uniform colored liquid layer can be formed and an image having a high density can be obtained.

Note that the transfer amount of the undercoat liquid layer per unit area was determined by the transfer test described below. After the completion of the semi-curing process (for example, after irradiation of active energy rays) and before droplets of colored liquid are ejected, a penetrating medium such as plain paper is pressed against the semi-cured undercoat liquid layer, It is defined by measuring the amount of the undercoat liquid transferred to the permeation medium.
For example, when the maximum discharge amount of the colored liquid is 600 × 600 dpi and the droplet ejection density is 12 picoliters per pixel (dot), the maximum weight m (colored liquid) of the colored liquid applied per unit area is 0.74 mg / cm ² (here, the density of the coloring liquid is assumed to be about 1.1 g / cm ³ ). Therefore, amount of undercoat liquid layer transferred is preferably a unit area is per 0.025 mg / cm ² or more 0.74 mg / cm ² or less, more preferably 0.037 mg / cm ² or more 0.25 mg / cm ² or less More preferably, it is 0.074 mg / cm ² or more and 0.148 mg / cm ² or less.

When forming a secondary color with the coloring liquid A and the coloring liquid B, it is preferable to apply the coloring liquid B on the semi-cured coloring liquid A.
FIG. 6 is a schematic cross-sectional view showing an embodiment of a printed material obtained by ejecting the colored liquid B onto the semi-cured colored liquid A. FIG. FIG. 6 shows a colored liquid A cured product 24 and a colored liquid B cured product 22 obtained by applying the colored liquid B to the semi-cured colored liquid A.
When the colored liquid B is ejected onto the semi-cured colored liquid A, a part of the colored liquid B enters the colored liquid A, and the colored liquid A exists below the colored liquid B. . That is, the printed matter obtained by applying the coloring liquid B onto the semi-cured coloring liquid A has a part of the coloring liquid B cured product 22 on the surface as shown in FIG. Part of the colored liquid B cured product 22 is embedded in the colored liquid A cured product 24. Further, a colored liquid A cured product is present below the colored liquid B cured product 22. Colored liquid A cured film (colored film A, colored liquid A cured product 24 in FIG. 6) and colored liquid B cured film (colored film B, colored liquid B cured product 22 in FIG. 6) are laminated. Good color reproduction is possible.

7 and 8 are schematic cross-sectional views showing one embodiment of a printed matter obtained by depositing the colored liquid B on the uncured colored liquid A. FIG. FIG. 7 shows a colored liquid A cured product 26 and a colored liquid B cured product 22 obtained by applying the colored liquid B to the uncured colored liquid A.
When the colored liquid B is ejected onto the uncured colored liquid A, all of the colored liquid B is embedded in the colored liquid A and / or the colored liquid A is not present below the colored liquid B. Become. That is, when a cross-sectional view of the obtained image is observed, as shown in FIG. 7, the entire colored liquid B cured product 22 is embedded in the colored liquid A cured product 26 and / or as shown in FIG. The colored liquid A cured product 26 does not exist in the lower layer of the colored liquid B cured product 22. In this case, even if the droplets of the colored liquid B are applied at a high density, the droplets are independent from each other, which causes a decrease in the saturation of the secondary color.

  FIG. 9 is a schematic cross-sectional view showing an embodiment of a printed matter obtained by ejecting the colored liquid B onto the completely cured colored liquid A. FIG. In FIG. 9, a colored liquid A cured product 28 and a colored liquid B cured product 22 obtained by adding the colored liquid B to the fully cured colored liquid A are shown. When the colored liquid B is ejected onto the completely cured colored liquid A, the colored liquid B will not enter the colored liquid A. As shown in FIG. 9, in the cross-sectional view of the obtained image, the colored liquid B cured product 22 does not sink into the colored liquid A cured product 28. Such a state causes the occurrence of droplet ejection interference, a uniform colored liquid film layer cannot be formed, and the color reproducibility is lowered.

From the viewpoint of forming a uniform colored liquid B liquid layer and suppressing the occurrence of droplet ejection interference, the unit area does not become independent when the colored liquid B liquid droplets are applied at high density. It is preferable that the transfer amount of the colored liquid A per unit is sufficiently smaller than the maximum droplet amount of the colored liquid B applied per unit area. That is, when the transfer amount (weight) per unit area of the colored liquid A layer is M (colored liquid A) and the maximum weight of the colored liquid B discharged per unit area is m (colored liquid B), M (colored) Liquid A) and m (colored liquid B) preferably satisfy the following relationship.
[M (colored liquid B) / 30] ≦ [M (colored liquid A)] ≦ [m (colored liquid B)]
Further, it is more preferable that [m (colored liquid B) / 20] ≦ [M (colored liquid A)] ≦ [m (colored liquid B) / 3], and [m (colored liquid B) / 10] ≦. It is more preferable that [M (colored liquid A)] ≦ [m (colored liquid B) / 5].
It is preferable that [m (colored liquid B) / 30] ≦ [M (colored liquid A)] because the occurrence of droplet ejection interference can be suppressed and the dot size reproducibility is excellent. Further, it is preferable that [M (colored liquid A)] ≦ [m (colored liquid B)] because a uniform colored liquid layer can be formed and an image having a high density can be obtained.

The transfer amount (weight) of the colored liquid A per unit area is determined by the transfer test described below. After completion of the semi-curing process (for example, after irradiation with active energy rays) and before droplets of the colored liquid B are ejected, a penetrating medium such as plain paper is pressed against the semi-cured colored liquid A layer. The weight of the colored liquid A transferred to the permeation medium is defined by weight measurement.
For example, assuming that the maximum discharge amount of the coloring liquid B is 12 picoliters per pixel at a droplet ejection density of 600 × 600 dpi, the maximum weight m (coloring liquid) of the coloring liquid B discharged per unit area is 0.74 mg / cm ² (here, the density of the colored liquid B is assumed to be about 1.1 g / cm ³ ). Thus, pigmented transfer amount of liquid A layer is preferably a unit area is per 0.025 mg / cm ² or more 0.74 mg / cm ² or less, more preferably 0.037 mg / cm ² or more 0.25 mg / cm ² Or less, more preferably 0.074 mg / cm ² or more and 0.148 mg / cm ² or less.

  In the case of a curing reaction based on an ethylenically unsaturated compound or a cyclic ether, the unpolymerization rate can be quantitatively measured by the reaction rate of an ethylenically unsaturated group or a cyclic ether group (described later).

  In the case where the semi-cured state of the undercoat liquid and / or the colored liquid is realized by a polymerization reaction of a polymerizable compound that starts polymerization by irradiation with active energy rays or heating, from the viewpoint of improving the scratching property of the printed matter, the unpolymerized rate (A (after polymerization) / A (before polymerization)) is preferably 0.2 or more and 0.9 or less, more preferably 0.3 or more and 0.9 or less, and 0.5 or more and 0.0 or less. Particularly preferably, it is 9 or less.

Here, A (after polymerization) is the absorbance of the infrared absorption peak due to the polymerizable group after the polymerization reaction, and A (before polymerization) is the absorbance of the infrared absorption peak due to the polymerizable group before the polymerization reaction. . For example, when the polymerizable compound contained in the undercoat liquid and / or the colored liquid is an acrylate monomer or a methacrylate monomer, an absorption peak based on a polymerizable group (acrylate group, methacrylate group) can be observed in the vicinity of 810 cm ^−1. The unpolymerization rate is preferably defined by the absorbance of the peak. When the polymerizable compound is an oxetane compound, an absorption peak based on a polymerizable group (oxetane ring) can be observed in the vicinity of 986 cm ⁻¹ , and the unpolymerization rate is preferably defined by the absorbance of the peak. When the polymerizable compound is an epoxy compound, an absorption peak based on a polymerizable group (epoxy group) can be observed in the vicinity of 750 cm ⁻¹ , and the unpolymerization rate is preferably defined by the absorbance of the peak.

  Moreover, as a means for measuring an infrared absorption spectrum, a commercially available infrared spectrophotometer can be used, which may be either a transmission type or a reflection type, and is preferably selected as appropriate in the form of a sample. For example, it can be measured using an infrared spectrophotometer FTS-6000 manufactured by BIO-RAD.

<Step of completely curing the image>
The “complete curing” in the present invention refers to a state in which the inside and the surface of the undercoat liquid and the coloring liquid are completely cured. Specifically, after the completion of the complete curing process (for example, after irradiation with active energy rays or after heating), whether the surface of the undercoat liquid or colored liquid was transferred to the permeation medium by pressing the permeation medium such as plain paper. It can be judged depending on why. That is, the case where no transfer is performed is called a completely cured state.
As a curing means for completely curing the image, a light source for irradiating active energy rays, a heater such as an electric heater or an oven, and the like can be selected according to the purpose.
As the active energy ray, in addition to ultraviolet rays, for example, visible light, α ray, γ ray, X ray, electron beam and the like can be used. Of these, the active energy rays are preferably electron beams, ultraviolet rays and visible rays, and ultraviolet rays are particularly preferred from the viewpoint of cost and safety.
Full amount of energy required for the curing reaction, the composition, in particular depends on the type and content of the polymerization initiator, it is generally preferred is the extent 100 mJ / cm ² or more 10,000 / cm ² or less.
Suitable devices for irradiating active energy rays include metal halide lamps, mercury lamps, LED light sources, and the like.

In addition, when energy is applied by the heating, a device that generates heat can be used as the heating means. In this case, it is preferable that the base material to which the undercoat liquid and the coloring liquid are applied is heated for 0.5 seconds to 10 seconds under the condition that the surface temperature of the base material is in a temperature range of 50 ° C. or higher and 100 ° C. or lower. .
In the case of heating, the temperature rise increases the curing reaction by polymerization or crosslinking of the polymerizable compound, and the shape formed by the collision of the droplets becomes stronger. This is preferable because a strong image can be obtained.
Heating can be performed using a non-contact type heating means, and a heating device that passes through a heating furnace such as an oven or a heating device that exposes the entire surface of ultraviolet light, visible light, infrared light, or the like is suitable. It is.
Examples of light sources suitable for exposure as the heating means include metal halide lamps, xenon lamps, tungsten lamps, carbon arc lamps, mercury lamps and the like.

<Means for controlling humidity>
In addition, from the viewpoint of controlling the cured state of the image, in the step of semi-curing the undercoat liquid and / or the step of completely curing the image, the humidity of the semi-cured region of the undercoat liquid and / or the region of the region where the image is completely cured. It is preferable to have a means for controlling.
From the viewpoint of obtaining a preferable semi-cured state, the preferred humidity of the semi-cured region of the undercoat liquid is preferably 40% or more and 80% or less, and the relative humidity in the air is 50% or more and 70%. It is more preferable that the relative humidity in air is 55% or more and 65% or less. The preferred semi-cured state is as described above.
From the viewpoint of improving the curability of the image, it is preferable that the relative humidity in the region where the image is completely cured is 50% or less, and the relative humidity in the air is 40% or less. More preferably, the relative humidity in the air is particularly preferably 30% or less.
The means for controlling the humidity is not particularly limited, but a commercially available humidifier or dehumidifier can be used. From the viewpoint of space saving of the apparatus and ease of control, it is preferable to use a commercially available air conditioning unit. Examples of commercially available air conditioning units include the precision air conditioning unit (temperature / humidity control unit) manufactured by Apiste PAU series (PAU-300S-HC, PAU-A920S-HC, PAU-A1400S-HC, PAU-A2600S-HC, PAU-A3500S-HC).

In FIG. 1, four color liquids of cyan, magenta, yellow, and black are used. However, the present invention is not limited to this, and a white color liquid can also be used. The order of the colored liquids to be ejected is not particularly limited, but it is preferable to apply the colored liquid with low brightness to the recording medium. When four colors of cyan, magenta, yellow and black are used, cyan It is preferably applied on the recording medium in the order of magenta → yellow → black. Further, in the case of using a coloring liquid of five colors obtained by adding white to this, it is preferable to apply the coloring liquid in the order of white → cyan → magenta → yellow → black.
At least one colorant may be used, but in order to obtain a full-color image, four colorants of cyan, magenta, yellow, and black, or five colorants of cyan, magenta, yellow, black, and white are used. It is preferable to do. Furthermore, the present invention is not limited to this, and eight colored liquids of cyan, light cyan, magenta, light magenta, gray, black, white, and yellow can be used.

In the present invention, instead of the full-line head method shown in FIGS. 1 and 10A, a full-line head method that does not have the semi-curing step of the colored liquid shown in FIG. 10B can be used. However, as shown in FIG. 10C, the shuttle scan method can be used. In FIGS. 10A to 10C, the undercoat layer application step, the semi-curing step of the undercoat solution, or the light irradiation step to the undercoat solution are omitted.
In FIG. 10A, the recording medium 70 is conveyed in the direction of arrow D, and cyan colored liquid is ejected onto the recording medium 70 by the cyan inkjet head 40C. Subsequently, the cyan coloring liquid is brought into a semi-cured state by the ultraviolet irradiation device (semi-curing device) 50C. Similarly, discharge of magenta colored liquid by the magenta inkjet head 40M, semi-curing of the discharged magenta colored liquid by the ultraviolet irradiation device 50M, discharge of the yellow colored liquid by the yellow inkjet head 40Y, ultraviolet irradiation of the discharged yellow colored liquid Semi-curing by the apparatus 50Y and discharging of the black coloring liquid by the black inkjet head 40K are performed. Finally, the undercoat liquid and the colored liquid are completely cured by the ultraviolet irradiation device (complete curing device) 60. The ultraviolet irradiation device (semi-curing device) 50 and the ultraviolet irradiation device (complete curing device) 60 include a hot cathode tube 56 that generates ultraviolet light in the lamp house 52, and cools the hot cathode tube 56. The cooling fan 54 is provided.
The full line head method shown in FIG. 10B is the same as the full line head method shown in FIG. 10A except that the ultraviolet irradiation devices (semi-curing devices) 50C, 50M, and 50Y are not provided.
In the shuttle scan method shown in FIG. 10C, the recording medium 70 is conveyed from the front side to the back side of the paper surface, and image formation is performed while the carriage moves in the paper width direction of the conveyed recording medium. The carriage conveyance direction is indicated by an arrow C. In the shuttle scan method shown in FIG. 10C, the colored liquid is not semi-cured but is completely cured by the ultraviolet irradiation device 60.

In the case of using (1) an undercoat liquid containing a photoacid generator and a cationically polymerizable compound, and (2) an undercoat liquid containing a photoacid generator, a radical polymerizable compound and a radical polymerization initiator. It is preferable to have a step of semi-curing the undercoat liquid, and it is particularly preferable to have a step of semi-curing by light irradiation. Thereby, while being able to improve the base-material adhesiveness of a coloring liquid, in a semi-hardening process, an acid generate | occur | produces from a photo-acid generator and it is preferable since the internal curability of a coloring liquid improves.
On the other hand, (3) when using the undercoat liquid containing a photo-acid generator and a solvent, it is preferable to have the process of removing a solvent, and the process of light irradiation. In this case, it is preferable because an acid is generated from the photoacid generator by the light irradiation step and the internal curability of the colored liquid is improved. In the case of the mode (3), there is no step of semi-curing the undercoat layer.
Among these, (1) an undercoat liquid containing a photoacid generator and a cationic polymerizable compound, and (2) an undercoat liquid containing a photoacid generator, a radical polymerizable compound and a radical polymerization initiator are used. It is preferable to use (1) an undercoat liquid containing a photoacid generator and a cationically polymerizable compound.

<Recording medium>
In the present invention, the material used for the recording medium is not particularly limited, and any material may be used. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. A preferable support includes a polyester film and an aluminum plate.
In the present invention, a non-absorbable recording medium is preferably used as the recording medium. In the ink jet recording method, by applying the coloring liquid after applying the undercoat liquid, high-definition is achieved with respect to various non-absorbent recording media that have so far been difficult to form fine images due to droplet ejection interference. An image can be formed.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not restrict | limited to these.
The materials used in the present invention are as follows.
PB15: 3 (IRGALITE BLUE GLO; Ciba Specialty Chemicals, cyan pigment)
PV19 (CINQUASIA MAGENTA RT-355D; manufactured by Ciba Specialty Chemicals, magenta pigment)
PY120 (NOVOPERM YELLOW H2G; manufactured by Clariant, yellow pigment)
Carbon black (SPECIAL BLACK 250; manufactured by Degussa, black pigment)
BYK-168 (manufactured by Big Chemie, dispersant)
Solsperse 5000 (Noveon, dispersant)
Rapidure DVE3 (triethylene glycol divinyl ether; manufactured by GAF, diluent)
DPGDA (dipropylene glycol diacrylate; manufactured by Daicel Cytec Co., Ltd., polyfunctional monomer)

(Preparation of cyan pigment dispersion)
PB15: 3 (IRGALITE BLUE GLO) 30 parts by weight Rapicure DVE3 50 parts by weight BYK-168 20 parts by weight The above components were mixed and stirred with a stirrer for 1 hour. The mixture after stirring was dispersed by bead mill dispersion to obtain Pigment Dispersion A. Dispersion conditions were as follows: zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 3 hours. Cyan pigment dispersion A was obtained through the above steps.

(Preparation of magenta pigment dispersion)
PV19 (CINQUASIA MAGENTA RT-355D) 30 parts by weight Rapicure DVE3 28 parts by weight BYK-168 42 parts by weight The above components were mixed and stirred with a stirrer for 1 hour. The mixture after stirring was dispersed by bead mill dispersion to obtain Pigment Dispersion A. Dispersion conditions were as follows: zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 6 hours. Magenta pigment dispersion A was obtained through the above steps.

(Preparation of yellow pigment dispersion)
PY120 (NOVOPERM YELLOW H2G) 30 parts by weight Rapicure DVE3 28 parts by weight BYK-168 42 parts by weight The above components were mixed and stirred for 1 hour. The mixture after stirring was dispersed by bead mill dispersion to obtain Pigment Dispersion A. Dispersion conditions were as follows: zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 6 hours. A yellow pigment dispersion A was obtained through the above steps.

(Preparation of black pigment dispersion)
Carbon black (SPECIAL BLACK 250) 40 parts by weight Rapidure DVE3 29 parts by weight BYK-168 30 parts by weight Solsperse 5000 1 part by weight The above components were mixed and stirred with a stirrer for 1 hour. The mixture after stirring was dispersed by bead mill dispersion to obtain Pigment Dispersion A. Dispersion conditions were as follows: zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 3 hours. The black pigment dispersion A was obtained through the above steps.

(Preparation of coloring liquid and undercoat liquid)
The components shown in Table 1 (unit: parts by weight) were mixed with stirring and dissolved to obtain a colored liquid and an undercoat liquid (both are collectively referred to as a liquid composition). In addition, when the surface tension of these liquid compositions was measured at a liquid temperature of 25 ° C. by the Wilhelmy method using a surface tension meter (manufactured by Kyowa Interface Science Co., Ltd., surface tension meter CBVP-Z, etc.) The surface tension of the colored liquid was also in the range of 25 to 27 mN / m. On the other hand, the surface tension of the undercoat liquid was in the range of 21 to 22 mN / m.

Each component used in the above table is described below.
Polymerizable compound A: OXT-221 (bis (3-ethyl-3-oxetanylmethyl) ether; manufactured by Toagosei Co., Ltd., compound having an oxetane ring)
Polymerizable compound B: OXT-101 (3-ethyl-3-hydroxymethyloxetane; manufactured by Toagosei Co., Ltd., compound having an oxetane ring)
Polymerizable compound C: OXT-211 (3-phenyl-3-phenoxymethyloxetane; manufactured by Toagosei Co., Ltd., compound having an oxetane ring)
Polymerizable compound D: Cel3000 (1, 2: 8,9 diepoxy limonene; manufactured by Daicel Chemical Industries, Ltd., a compound having an oxirane group)
Polymerizable compound E: DPGDA (dipropylene glycol diacrylate; manufactured by Daicel Cytec Co., Ltd., polyfunctional monomer)
Polymerizable compound F: A-DPH (dipentaerythritol hexaacrylate; manufactured by Shin-Nakamura Chemical Co., Ltd., polyfunctional monomer)
Surfactant A: BYK-307 (manufactured by Big Chemie, surfactant)
Polymerization inhibitor A: FIRSTCURE ST-1 (manufactured by Albemarle)
Polymerization initiator A: IRGACURE 250 (iodonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexafluorophosphate (1-) and propylene carbonate mixture; manufactured by Ciba Specialty Chemicals, Photopolymerization initiator)
Polymerization initiator B: IRGACURE 819 (manufactured by Ciba Specialty Chemicals, photopolymerization initiator)
Polymerization initiator C: Benzophenone (manufactured by Wako Pure Chemical Industries, Ltd., photopolymerization initiator)
Sensitizer A: 9,10-dibutoxyanthracene Sensitizer B: Speedcure DETX (2,4-diethylthioxanthone; manufactured by Lambson, sensitizer)
Organic solvent A: MMPG (manufactured by Daicel Chemical Industries, Ltd., 1-methoxy-2-propanol)

(Image recording device)
The prepared colored liquids for four colors (C1 or C2, M1 or M2, Y1 or Y2, Bk1 or Bk2) are ink jet printers (Toshiba TEC head mounted = droplet ejection frequency: 6.2 KHz, number of nozzles: 636, Nozzle density: 300 npi (nozzle / inch, the same applies hereinafter), drop size: 6 pl to 42 pl, 2 variable heads arranged in 7 stages and 600 npi with 4 sets of fully lined headsets loaded) did.
The head is fixed to the machine in the order of cyan, magenta, yellow, and black from the upstream side of the recording medium conveyance direction, and further, an undercoat liquid roll coater and a semi-curing light source (light irradiation light source) (ultra-high pressure light source) (ultra-high pressure) Mercury lamp: light intensity 100 mW / cm ² ) was installed. Here, as the undercoat liquid, undercoat liquids (L1 to L4) were used.
In addition, when using undercoat liquid L4, after apply | coating undercoat liquid, before performing light irradiation, the drying process was performed in order to remove a solvent.
For the cyan, magenta, and yellow heads that have a structure in which the recording medium can be moved immediately below the heads and that are loaded with colored liquids (C1 or C2, M1 or M2, Y1 or Y2, Bk1 or Bk2). a recording medium travel direction, each pinning curing light source (semi-curing light source, ultra-high pressure mercury lamp: light intensity 100 mW / cm ²⁾ of the disposed on the downstream black ink head metal halide lamp (light intensity 3000 mW / cm ²⁾ Five were installed. In addition, the irradiation energy by a metal halide lamp can be adjusted to 300-1500 mJ / cm < ² > according to the number of the metal halide lamps to light. Specifically, 300 mJ / cm ² (1 unit lighting), 600 mJ / cm ² (2 units lighting), 900 mJ / cm ² (3 units lighting), 1,200 mJ / cm ² (4 units lighting), 1,500 mJ / Cm ² (5 units lit).
The recording medium was transported on a roll, and an image of 600 dpi × 600 dpi was formed on the recording medium. Here, a plastic film A (thickness 50 μm; transparent polyethylene) and a plastic film B (thickness 100 μm; transparent PET) were used as recording media.

Example 1
First, using the above experimental machine, the printed matter A (600 dpi × 600 dpi secondary color (cyan and magenta, yellow and cyan, yellow and magenta) background, or 600 dpi × 600 dpi primary color (cyan, magenta, Yellow) background with black letters “Fuji” (Times New Roman, 30 pt)), Print B (600 dpi × 600 dpi secondary color background (cyan and magenta, yellow and cyan, yellow and magenta)), or 600 dpi × A missing character “Fuji” (Times New Roman, 30 pt) was created on a background of 600 dpi primary colors (cyan, magenta, yellow). In addition, the undercoat liquid cured film has come out on the surface in the missing character part of the image B here.
FIG. 11 shows a printed matter A and a printed matter B created in the example. The printed material A (FIG. 11A) has a black character 401 formed on the background 400, and the printed material B (FIG. 11B) has a missing character 402 formed on the background 400.

The printing procedure is as follows (1) to (10).
(1) The undercoat liquid (L1) was uniformly applied to a thickness of 5 μm by a roll coater (application speed: 400 mm / s).
(2) After applying the undercoat liquid (L1), exposure was performed with a light source for semi-curing (light intensity 100 mW / cm ² ), and the applied undercoat liquid (undercoat liquid L1) was in a semi-cured state.
(3) A cyan color liquid (C1) was applied on the recording medium by a cyan head to form a cyan image.
(4) Exposure was performed with a light source for pinning (light intensity 100 mW / cm ² ), and the cyan coloring liquid was brought into a pinning cured state (semi-cured state).
(5) A magenta colored liquid (M1) was applied onto the recording medium by a magenta head to form a magenta image.
(6) Exposure was performed with a light source for pinning (light intensity 100 mW / cm ² ), and the magenta coloring liquid was brought into a pinning cured state (semi-cured state).
(7) A yellow coloring liquid (Y1) was applied on the recording medium by a yellow head to form a yellow image.
(8) Exposure was performed with a light source for pinning (light intensity 100 mW / cm ² ), and the yellow coloring liquid was brought into a pinning cured state (semi-cured state).
(9) A black color liquid (Bk1) was applied to the recording medium by a black head to form a black image.
(10) Exposure was performed with a metal halide lamp (light intensity: 3,000 mW / cm ² ) to completely cure the image. The exposure energy was adjusted to 300 to 1,500 mJ / cm ² depending on the number of metal halide lamps to be lit.

Here, the conveyance speed of the recording medium was 400 mm / s, and the amount of ink liquid per dot was about 18 picoliters. When forming an image of a tertiary color (for example, cyan, magenta, and yellow), (8) and (9) were omitted in the above procedure. Further, when forming an image of a secondary color (for example, cyan and magenta), (6) to (9) were omitted in the above procedure. When forming an image of a primary color (for example, yellow), (3) to (6), (8), and (9) were omitted in the above procedure.
When using the undercoat liquid L4, the coating amount is 5 g / m ^2, and after applying the undercoat liquid with a roll coater, a solvent removing step (drying step) is performed, and light irradiation is performed in the same manner as in (2). went.

(Evaluation of ink curability)
Sensory evaluation was performed according to the following evaluation criteria.
Sensory evaluation of the printed surface of the printed material after exposure was performed according to the following criteria.
○: The surface and the inside are completely cured, and there is no problem in use.
Δ: The surface is cured, but the inside is semi-cured.
X: The surface is sticky and there are problems in use such as color transfer.

(Fixability to substrate)
Image fixability was defined by the exposure energy at which film peeling and tearing due to guitar pick rubbing after printing were eliminated. If the printed material is rubbed 5 times with a guitar pick after printing and no film peeling or tearing occurs, it is judged that there is no peeling or tearing of the film due to nail scrubbing (where the film tearing is mainly due to poor internal curing) To do.)
The exposure ^{energy, 200mJ / cm 2, 400mJ /} cm 2, 600mJ / cm 2, 800mJ / cm 2, was varied with 1,000 mJ / cm ^2.
Here, it is preferable that the exposure energy is low, and it is particularly preferably 600 mJ / cm ² or less.

(Substrate curl)
The printed matter was evaluated using a polyethylene film.
○: Curling of the substrate is hardly observed, and there is no problem even if it is used as it is.
(Triangle | delta): The curl of a base material is seen.
X: Level where the base material is greatly curled inward and has a problem in use.
Ink curable evaluation and adhesion evaluation were evaluated using a PET (polyethylene terephthalate, manufactured by Higashiyama Film Co., Ltd.) base material. Moreover, the curl test of the base material was evaluated using a polyethylene film.

A hand-coated product was prepared according to the following procedure.
An appropriate amount of undercoat liquid was placed on the substrate, and an undercoat layer (10 μm or 16 μm) was formed using a K2 or K3 bar (manufactured by RK Print Coat), and then pinning exposure was performed with a light source for pinning (400 mW / cm ² ). Subsequently, an appropriate amount of coloring liquid was applied, and solid films having two types of film thickness were prepared using K2 and K3 bars (manufactured by RK Print Coat), and the curability of the ink was evaluated.
In addition, when undercoat liquid L4 was used, after forming an undercoat layer similarly, after performing the solvent removal process (drying process), light irradiation (400 mW / cm < ² >) was performed.

(Examples 1-6, Comparative Examples 1-3)
Evaluation was performed in the same manner as in Example 1 except that the undercoat liquid and coloring liquid used were changed as shown in Table 5 below.
The results are shown in the table below.

It is a conceptual diagram of the inkjet recording method which can be used conveniently for this invention. It is a cross-sectional schematic diagram which shows one embodiment of the printed matter obtained by droplet-dropping a colored liquid on the semi-hardened undercoat liquid layer. It is a cross-sectional schematic diagram which shows one embodiment of the printed matter obtained by droplet-dropping a colored liquid on the uncured undercoat liquid layer. It is a cross-sectional schematic diagram which shows another embodiment of the printed matter obtained by depositing a coloring liquid on the uncured undercoat liquid layer. It is a cross-sectional schematic diagram which shows one embodiment of the printed matter obtained by depositing a coloring liquid on the undercoat liquid layer of a completely hardened state. It is a cross-sectional schematic diagram which shows one embodiment of the printed matter obtained by depositing the coloring liquid B on the semi-cured coloring liquid A. It is a cross-sectional schematic diagram which shows one embodiment of the printed matter obtained by ejecting the coloring liquid B on the uncured coloring liquid A. It is a cross-sectional schematic diagram which shows other one Embodiment of the printed matter obtained by droplet-dropping the coloring liquid B on the uncured coloring liquid A. It is a cross-sectional schematic diagram which shows one embodiment of the printed matter obtained by depositing the coloring liquid B on the coloring liquid A in a completely cured state. It is a conceptual diagram of the coloring liquid discharge process which can be used conveniently for this invention. It is a conceptual schematic diagram which shows the image formed in the Example.

Explanation of symbols

1 means for applying undercoat liquid 2 means for semi-curing undercoat liquid 3Y means for applying yellow color liquid 3C means for applying cyan color liquid 3M means for applying magenta color liquid 3K means for applying black color liquid 4Y yellow coloration 4C means for semi-curing the liquid 4M means for semi-curing the cyan colored liquid 4M means for semi-curing the magenta colored liquid 6K means for semi-curing the black colored liquid 6 Recording medium 7A Recording medium conveying means (film unwinding machine)
7B Recording medium transport means (film winder)
40C, 40M, 40Y, 40K Inkjet head 50C, 50M, 50Y UV irradiation device (semi-curing device)
52 Lamp House 54 Cooling Fan 56 Hot Cathode Tube 60 UV Irradiation Device (Complete Curing Device)
70 Recording medium 400 Background 401 Black character 402 Missing character

Claims (10)

A cationic polymerizable compound, a cationic polymerization initiator, and a coloring liquid containing a coloring agent;
An ink set comprising an undercoat liquid containing a photoacid generator.   The ink set according to claim 1, wherein the undercoat liquid further contains a cationically polymerizable compound.   The ink set according to claim 1, wherein the cationically polymerizable compound includes at least one oxetane group-containing compound and at least one oxirane group-containing compound.   The ink set according to claim 1, wherein the undercoat liquid further contains a radical polymerization initiator and a radical polymerizable compound.   The ink set according to claim 1, wherein the undercoat liquid contains a surfactant.   The ink set according to claim 1, wherein the surface tension γA of the coloring liquid and the surface tension γB of the undercoat liquid satisfy a relational expression of γA> γB.   The ink set according to any one of claims 1 to 6, which is for inkjet recording. An undercoat liquid application step for applying an undercoat liquid on the recording medium;
A light irradiation step of generating an acid by irradiating the undercoat liquid with light;
An image forming step of forming an image by discharging a colored liquid onto the undercoat liquid;
A complete curing step of completely curing the undercoat liquid and the coloring liquid,
The ink set according to claim 1, wherein the ink set includes an undercoat liquid and a colored liquid. An undercoat liquid application step for applying an undercoat liquid on the recording medium;
An undercoat liquid semi-curing step for semi-curing the undercoat liquid;
An image forming step of forming an image by discharging a colored liquid onto the semi-cured undercoat liquid; and
A complete curing step of completely curing the undercoat liquid and the coloring liquid,
The ink set according to claim 1, wherein the ink set includes an undercoat liquid and a colored liquid.   The inkjet recording method according to claim 9, further comprising means for controlling a humidity of an area where the undercoat liquid is semi-cured and / or an area where the undercoat liquid is fully cured in the undercoat liquid semi-curing process and / or the complete curing process. .

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