WO2006054441A1

WO2006054441A1 - Composition curable with actinic ray, actinic-ray-curable ink-jet ink, method of forming image with the same, and ink-jet recorder

Info

Publication number: WO2006054441A1
Application number: PCT/JP2005/019996
Authority: WO
Inventors: Toshiyuki Takabayashi
Original assignee: Konica Minolta Medical & Graphic, Inc.
Priority date: 2004-11-17
Filing date: 2005-10-31
Publication date: 2006-05-26
Also published as: JPWO2006054441A1

Abstract

An actinic-ray-curable composition which generates no wrinkles even when used in various printing environments; and a method of image formation by which a high-resolution image having excellent character quality and free from color mixing can be stably recorded with an actinic-ray-curable ink-jet ink comprising the composition. The actinic-ray-curable composition is characterized by containing photopolymerizable compounds which comprise at least one member selected among monofunctional alicyclic epoxy compounds respectively represented by the following general formulae (1) to (4) and at least one member selected among (meth)acrylate monomers and oligomers.

Description

Specification

Actinic ray curable composition, actinic ray curable inkjet ink, image forming method using the same, and inkjet recording apparatus

Technical field

[0001] The present invention relates to an actinic ray curable composition, an actinic ray curable ink jet ink that can stably reproduce a high-definition image on various recording materials even under various printing environments, and the like. The present invention relates to an image forming method and an ink jet recording apparatus using the same.

Background art

In recent years, the ink jet recording method can easily and inexpensively create an image, and thus has been applied to various printing fields such as photographs, various printing, marking, special printing such as a color filter. In particular, an ink jet recording apparatus capable of emitting and controlling fine ink droplets, an ink-jet ink and ink-jet ink with improved color reproduction range, durability, ejection suitability, etc., color development of color materials, surface It is also possible to obtain image quality comparable to silver halide photography by using special paper with dramatically improved gloss. The improvement in image quality in today's inkjet recording system is achieved only when all of the recording devices, ink, and special paper are available.

[0003] However, in an inkjet system that requires dedicated paper, the recording medium is limited and the cost of the recording medium increases. Therefore, many attempts have been made to record using a transferred medium hank jet method different from that for special paper. Specifically, a phase change inkjet method using a wax ink that is solid at room temperature, a solvent-based inkjet method that uses an ink mainly composed of a fast-drying organic solvent, and an ultraviolet curable type that is crosslinked by ultraviolet (UV) light after recording. For example, an inkjet method.

[0004] In particular, the ultraviolet curable ink jet method has been attracting attention in recent years because it has a relatively low odor compared to the solvent-based ink jet method, and can be recorded on a recording medium that does not dry quickly and absorbs ink. image type forming method using the ultraviolet ray curable ink-jet ink, such as has been disclosed (for example, Patent Document 1, 2 reference.) ₀

[0005] However, even if these various ink-jet inks are used, the type of recording material Depending on the printing environment, the dot diameter after landing is greatly changed, and it is difficult to stably form high-definition images on various recording materials.

[0006] In addition, the ultraviolet curable ink-jet ink contains a photo-thion polymerizable compound such as a compound having an oxetane ring or an alicyclic epoxy compound as a photopolymerizable compound. Ink-jet inks using a curable composition (see, for example, Patent Documents 3 to 6) are not subject to oxygen-inhibiting action, but differ in the environment during curing (for example, temperature and humidity). As a result of being easily affected by moisture (humidity) at the level, there are problems such as generation of wrinkles due to shrinkage of the cured film and poor curability.

[0007] Furthermore, an active energy ray-curable composition is disclosed in which a light-power thione polymerizable compound that solves these problems and a (meth) acrylate monomer are used in combination (for example, see Patent Document 7). However, this configuration alone is not sufficient to solve the above problems, and in particular, the problem of wrinkles has not yet been solved. Patent Document 1: JP-A-6-200204 (Claims, Examples)

Patent Document 2: JP 2000-504778 (Claims, Examples)

Patent Document 3: Japanese Patent Laid-Open No. 2001-220526 (Claims, Examples)

Patent Document 4: Japanese Patent Laid-Open No. 2002-188025 (Claims, Examples)

Patent Document 5: Japanese Patent Application Laid-Open No. 2002-317139 (Claims, Examples)

Patent Document 6: Japanese Patent Laid-Open No. 2003-55449 (Claims, Examples)

Patent Document 7: Japanese Patent Application Laid-Open No. 2003-73481 (Claims, Examples)

Disclosure of the invention

Problems to be solved by the invention

[0008] The present invention has been made in view of the above problems, and an object of the present invention is an actinic ray curable composition that does not generate wrinkles even under various environments, and an actinic ray using the same. An object of the present invention is to provide an image forming method and an ink jet recording apparatus capable of stably recording a high-definition image having excellent character quality and no color mixing by using a curable ink jet ink.

Means for solving the problem

[0009] The above object of the present invention can be achieved by the following configurations. [0010] 1. As a photopolymerizable compound, at least one monofunctional alicyclic epoxy compound represented by the following general formulas (1) to (4) is selected, and a (meth) acrylate monomer And an actinic ray curable composition comprising at least one selected from oligomers.

[0011] [Chemical 1]

[In the formula, R, R, R, R, R, R, R, and R are each a hydrogen atom and an alkyl having 1 to 5 carbon atoms a b d e g h j k

R and R, R and R, R and R, R and R are simultaneously a b d e g h j k

Does not represent a hydrogen atom. R ~ R

Each of 1 32 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a substituted alkyl group. R, R, R, and R are each c 2 to 10 carbon atoms c f i 1

An alkyl group or a substituted alkyl group is represented. ]

2. As a photopolymerizable compound, it contains at least one selected from monofunctional alicyclic epoxy compounds represented by the following general formulas (1) to (4) and a compound containing a maleimide skeleton. An actinic ray curable composition characterized by the above.

[0013] [Chemical 2]

[Wherein R, R, R, R, R, R, R, R are each a hydrogen atom, an alkyl having 1 to 5 carbon atoms a b d e g h j k

R and R, R and R, R and R, R and R are simultaneously a b d e g h j k

Does not represent a hydrogen atom. R ~ R

Each of 1 32 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a substituted alkyl group. R, R, R

c f i and R

1 represents an alkyl group having 2 to 10 carbon atoms or a substituted alkyl group. ]

3. As a photopolymerizable compound, at least one selected from the following monofunctional alicyclic epoxy compounds represented by the following general formulas (1) to (4), a polyene compound and a polythiol compound An actinic ray curable composition characterized by containing.

[0015] [Chemical 3]

[Wherein, R, R, R, R, R, R, R, R are each a hydrogen atom, an alkyl having 1 to 5 carbon atoms a b d e g h j k

R and R, R and R, R and R, R and R are simultaneously a b d e g h j k

Does not represent a hydrogen atom. R ~ R

c f i and R

4. The force of any one of 1 to 3 above, wherein the molecular weight of the monofunctional alicyclic epoxy compound represented by the general formulas (1) to (4) is 190 or more and 300 or less 1 The actinic ray curable composition according to Item.

[0017] 5. The actinic ray curable composition as described in any one of 1 to 4 above, wherein the photopolymerizable compound further comprises a compound having an oxetane ring.

[0018] 6. The actinic ray curable composition according to any one of 1 to 5 above, wherein the viscosity at 25 ° C is 7 mPa's or more and 50 mPa's or less.

[0019] 7. The actinic radiation curable inkjet ink, wherein the actinic radiation curable composition according to any one of 1 to 6 above contains a pigment.

[0020] 8. An image forming method in which the actinic radiation curable inkjet ink described in 7 above is discharged from an inkjet recording head onto a recording material, and printing is performed on the recording material. After the ink jet type ink is landed on the recording material, it is 0.001 seconds or more, 1 An image forming method comprising irradiating actinic rays for 0 second or less.

[0021] 9. An image forming method in which the actinic radiation curable inkjet ink described in 7 is discharged onto a recording material from an inkjet recording head, and printing is performed on the recording material. An image forming method, wherein the total ink film thickness after the ink jet ink is landed on the recording material and cured by irradiation with actinic rays is 2 m or more and 25 m or less.

[0022] 10. An image forming method in which the actinic ray curable ink jet ink described in 7 above is ejected onto a recording material from an ink jet recording head, and printing is performed on the recording material. An image forming method, wherein the volume of ink droplets discharged from each nozzle is 2 pl or more and 15 pl or less.

[0023] 11. The image forming method according to any one of 8 to 10, wherein the inkjet recording head force is a line head system.

[0024] 12. An ink jet recording apparatus for use in the image forming method according to any one of 8 to 11, comprising an actinic ray curable ink jet ink and an ink jet recording head.

An ink jet recording apparatus comprising: a mechanism for discharging the actinic ray curable ink jet ink after heating to 35 ° C to 100 ° C.

The invention's effect

[0025] According to the present invention, an actinic ray curable composition that does not generate wrinkles even under various environments can be obtained, and an ink jet ink using the composition can provide high-definition with excellent character quality and no color mixing. It was possible to provide an image forming method and an ink jet recording apparatus capable of recording a stable image stably.

Brief Description of Drawings

FIG. 1 is a front view showing an example of a main part configuration in an ink jet recording apparatus of the present invention.

FIG. 2 is a top view showing another example of the main configuration of the ink jet recording apparatus of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0027] As a result of intensive studies in view of the above-mentioned problems, the present inventors have found that a conventional actinic ray type ink jet New monofunctional alicyclic epoxy compounds and (meth) atallylate monomers and / or UVR6110 manufactured by Dow Chemical Co., Ltd. and Celoxide 2021P, Celoxide 3000, and Celoxide 2000 manufactured by Daicel Chemical Industries, Ltd. Actinic ray curable composition containing oligomer or a novel monofunctional alicyclic epoxy compound and a compound containing maleimide skeleton, or novel monofunctional alicyclic epoxy It has been found that an actinic ray curable composition containing a compound, a polyene compound and a polythiol compound can produce an actinic ray curable composition which does not generate wrinkles even under various environments. It is up to the present invention.

[0028] In particular, when the actinic ray curable composition of the present invention contains a pigment and is used as an actinic ray curable ink jet ink, the ejection stability, which is the biggest problem in ink jet recording, is considered. This is an epoch-making configuration that can form a high-quality image with excellent reproducibility, regardless of the printing environment (for example, temperature and humidity).

[0029] Details of the present invention will be described below.

[0030] In the actinic ray curable composition of the present invention, as the photopolymerizable compound, the monofunctional alicyclic epoxy compound strength represented by the general formulas (1) to (4) is selected. One of the characteristics is that it contains one species.

[0031] In the general formulas (1) to (4), R, R, R, R, R, R, R, and R are each a hydrogen atom a b d e g h j k

Represents an alkyl group or substituted alkyl group having 1 to 5 carbon atoms, R and R, R and R, R and R a b d e g h

, R

j and R

k, each does not represent a hydrogen atom at the same time. R ~ R

Each of 1 32 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a substituted alkyl group. R, R, R, and R each represents c f i 1 each having 2 to C carbon atoms: L0 alkyl group or substituted alkyl group.

In the general formulas (1) to (4), a preferable molecular weight is 190 to 300. If the molecular weight is smaller than 190, the degree of positiveness may increase in mutagenicity (AMES) tests, etc., which may be undesirable for safety and health reasons. If the molecular weight exceeds 300, the viscosity is too high to handle. It becomes difficult.

[0033] The following are specific examples of monofunctional alicyclic epoxy compounds represented by the general formulas (1) to (4) according to the present invention. In the present invention, the present invention is limited to these exemplified compounds. It is not done. [0034] [Chemical 4]

EP-1

Mw: 268.39

Mw: 254.41

Mw: 268.33

EP -4

Mw: 200.23

Mw: 254.41

Mw: 224.38

[0035] The addition amount of the alicyclic epoxy compound in the actinic ray curable composition of the present invention is preferably 10 to 80% by mass. If it is less than 10% by mass, the curability changes significantly depending on the curing environment (temperature, humidity), making it difficult to use it stably. On the other hand, if the amount added exceeds 80% by mass, the physical properties of the cured film will be weakened. In the present invention, one type of alicyclic epoxy compound may be used alone, or two or more types of alicyclic epoxy compounds may be used in combination as appropriate in combination with known alicyclic epoxy compounds.

[0036] The alicyclic epoxy compound according to the present invention may be produced by any method! /, For example, Maruzen KK Publishing, 4th edition Experimental Chemistry Course 20 Organic Synthesis II, 213-, Heisei 4 years, Ed. By Alfr ea Hasfner, The chemistry of cyclic compounds-Small Ring Heterocycles part 3 Oxiranes, John & Wiley and Sons, An Inter science Publication, New York, 1985, Yoshimura, Adhesion, 29-12, 32, 198 5, Yoshimura, Adhesion, 30-5, 42, 1986, Yoshimura, Adhesion, 30-7, 42, 1986, Japanese Patent Application Laid-Open No. 1-100378, Japanese Patent Application No. 2-140732, Japanese Patent Application No. 2-182124, etc. It can be synthesized with reference.

[0037] In the active composition curable composition of the present invention, together with the alicyclic epoxy compound according to the present invention,

It is characterized in that it contains at least one compound that also has a (meth) acrylate monomer and / or oligomer power.

In the present invention, as the (meth) acrylate monomer and / or oligomer, any known (meth) acrylate monomer and / or oligomer can be used.

[0039] For example, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isoamyl styrene acrylate, isostearyl acrylate, 2-ethylhexyl diol diglycol acrylate, 2 —Hydroxybutyl acrylate, 2-Atarylloy hexetylhexahydrophthalic acid, butoxychetil acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxy polyethylene glycol acrylate, methoxypropylene glycol acrylate, phenol Shetyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate , 2-hydroxyl-3 phenoxypropyl attalylate, 2-atariloy oral kichetyl succinic acid, 2-acryloyl oral chechetyl phthalic acid, 2-atariloyloxetyl 2-hydroxyethyl phthalic acid, rataton-modified flexible Monofunctional monomers such as attalylate, t-butylcyclohexyl acrylate, triethylene glycol diatalate, tetraethylene glycol diatalate, polyethylene glycol diatalate, tripropylene glycol diatalate, polypropylene glycol diatalate, 1, 4 Butanediol ditalylate, 1, 6-hexanediol ditalylate, 1,9-nonanediol ditalylate, neopentyl glycol ditalylate, dimethylol-tricyclodecane ditalylate, bisphenol Over Bifunctional monomer such as EO-powered diatalylate of bisphenol A, PO-powered diatalylate of PO of bisphenol A, neopentylglycol ditalylate of hydroxybivalic acid, polytetramethylene glycol diatalate, trimethylolpropane tritalylate , EO-modified trimethylolpropane tritalylate, pentaerythritol tritalylate, pentaerythritol tetraatalylate, dipentaerythritol hexaatalylate, ditrimethylol propane pantetratalylate, glycerin propoxytritalate, force prolatatatone Trifunctional or higher functional groups such as modified trimethylol propane tritalylate, pentaerythritol ethoxytetraatalylate, and ratotatam modified dipentaerythritol hexaatalylate Multifunctional monomer.

In addition to this, polymerizable oligomers can also be applied in the same manner as the monomer. Examples of the polymerizable oligomer applicable to the present invention include epoxy acrylate, aliphatic urethane acrylate, aromatic urethane acrylate, polyester acrylate and linear acrylic oligomer.

[0041] From the viewpoints of sensitization, skin irritation, eye irritation, mutagenicity, toxicity, etc., among the above monomers, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate are particularly preferred. , Decyl acrylate, isomyristyl acrylate, isostearyl acrylate, ethoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, isobornyl acrylate, rataton modified flexible acrylate, tetra Ethylene glycol ditalylate, polyethylene glycol ditalylate, polypropylene glycol ditalylate, EO-modified trimethylolpropane tritalylate, dipentaerythritol hexaatalylate, dito Methylol propane tetraacrylate Atari, glycerin propoxylate tri Atari rate, Cau Purorata tons modified trimethylolpropane tri Atari rate, pentaerythritol tetraacrylate Atari rate, hexa Atari rate to force Puroratatamu modified dipentaerythritol are preferred.

[0042] Furthermore, among these, stearyl atylate, lauryl atylate, isostearyl atylate, ethoxydiethylene glycol atylate, isobornyl attalate, tetraethylene glycol ditalylate, EO-modified trimethylolpropane tritalylate, glycerin Propoxy triatalate, Cowprolatataton modified trimethylolpropane triatalyle Particularly preferred is a salt, force prolatatam modified dipentaerythritol hexaatalylate.

[0043] The actinic ray curable composition of the present invention is characterized by containing a compound containing a maleimide skeleton as a photopolymerizable compound together with the alicyclic epoxy compound according to the present invention.

[0044] A compound containing a maleimide skeleton that can be used in the present invention (hereinafter also referred to as maleimide compound) will be described. Examples of maleimide compounds that can be used in the present invention include, for example, JP-A-2000-211249, JP-A-2000-143729, JP-A-2000-144033, JP-A-2000-144041, JP-A-2000-264922, JP-A-11-264922. -No. 292874, No. 11- 1244 04, No. 11 124403, No. 11 302278 [described above] Maleimide compounds of various known structures can be used. These maleimide compounds can be synthesized by using a known synthesis method as described in, for example, JP 2000-211249. Further, these maleimide compounds may be used in combination with the (meth) acrylate monomer and / or oligomer.

The actinic ray curable composition of the present invention is characterized by containing a polyene and a polythiol compound as a photopolymerizable compound together with the alicyclic epoxy compound according to the present invention.

[0046] Examples of the polyene and polythiol compound applicable to the present invention include known compounds, for example, compounds described in JP-A-2001-26608.

The polyene according to the present invention refers to a polyfunctional compound having two or more carbon-carbon double bonds in one molecule. Examples of polyene include allylic alcohol derivatives, esters of (meth) acrylic acid and polyhydric alcohols, urethane (meth) acrylate and dibutenebenzene. One or more of these can be used.

[0048] Examples of the aryl alcohol derivative include triallyl isocyanurate, triallyl cyanurate, diallyl maleate, diallyl fumarate, diallyl adipate, diallyl phthalate, triallyl trimellitate, tetraallyl. Examples include rilpyromellitate, glyceryl diallyl ether, trimethylolpropane diallyl ether, pentaerythritol diallyl ether, and sorbitol diallyl ether.

[0049] Among the esters of (meth) acrylic acid and polyhydric alcohol, polyhydric alcohols include, for example, ethylene glycol, propylene glycol, 1,4 butanediol, 1,6- Examples include hexanediol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol.

[0050] Among these, triallyl isocyanurate is preferred in which at least one selected from the group strength of triallyl isocyanurate, triallyl cyanurate, and diallyl maleate is preferable in terms of reactivity with polythiol. Is more preferable.

[0051] The polythiol used in the present invention refers to a polyfunctional compound having two or more thiol groups in one molecule. Examples of the polythiol include esters of mercaptocarboxylic acid and polyhydric alcohol, aliphatic polythiols, and aromatic polythiols, and one or more of these can be used.

[0052] Among the esters of mercaptocarboxylic acid and polyhydric alcohol, examples of mercaptocarboxylic acid include thioglycolic acid, α-mercaptopropionic acid, and j8-mercaptopropionic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,4 butanediol, 1,6 hexanediol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol.

[0053] Examples of the aliphatic polythiols and aromatic polythiols include ethanedithiol, propanedithiol, hexamethylenedithiol, decamethylenedithiol, trilylene 2,4 dithiol, and xylenedithiol.

Of these, esters of mercaptocarboxylic acid and polyhydric alcohol are preferred from the viewpoint of low odor.

[0055] The polyene and polythiol compound may be used in combination with the (meth) acrylate monomer and / or oligomer.

[0056] In the actinic ray curable composition of the present invention, it is preferable to further use a compound having an oxetane ring. Examples of the oxetane compound that can be used include JP-A-2001-220.

Any known oxetane compounds as described in 526, 2001-310937 can be used.

[0057] In the actinic ray curable composition of the present invention, any known photo radical generator and / or photo acid generator is used as a photoinitiator.

[0058] Photoradical generators include arylalkyl ketones, oxime ketones, and thiobenzoic acid. Conventionally known photo radical generators such as s-phenol, titanocene, aromatic ketone, thixanthone, benzyl and quinone derivatives and ketocoumarins can be used. These compounds are described in detail in “Application of UV'EB Curing Technology and Production” (CMC Publishing Co., Ltd., edited by Yoneho Tabata, edited by Rad-Tech Study Group). Among them, acylphosphine oxysilphosphinate is a highly sensitive ink with a thickness of 5 to 12 m per color, as in the ink jet method, because absorption is reduced by photocleavage of the initiator. Especially effective for internal curing in images. Specifically, bis (2, 4, 6 trimethylbenzoyl) phenol phosphine oxide, bis (2, 6 dimethoxybenzoyl) 1, 2, 4, 4 trimethyl monopentyl phosphine oxide, etc. are preferred. Better!/,.

[0059] In addition, as in the case of the above-mentioned monomer, in consideration of safety, 1 hydroxy 1-cyclohexyl-phenol ketone, 2-methyl-1 [4- (methylthio) phenol] — 2 morpholinopropane 1 —One, bis (2,6 dimethoxybenzoyl) -1,2,4,4 trimethylone pentylphosphine oxide, 2-hydroxy-1,2-methyl 1-phenyl-propan 1-one (Darocur 1173, Merck) Are preferably used. A preferable addition amount is 1 to 6% by mass, preferably 2 to 5% by mass, based on the entire actinic ray curable composition.

[0060] As the photoacid generator, for example, a chemical amplification type photoresist or a compound used for photopower thione polymerization is used (edited by Organic Electronics Materials Research Group, "Organic Materials for Imaging", Bunshin Publishing ( 1993), pages 187-192). Examples of compounds suitable for the present invention are listed below.

[0061] First, B (CF)-, PF-, AsF-, SbF-, CF SO-- of aromatic compounds such as diazoum, ammonia, jordonium, snorehonum, phospho- um, etc. List salt

6 5 4 6 6 6 3 3

Togashi.

[0062] Specific examples of the chromium compounds that can be used in the present invention are shown below.

[0063] [Chemical 5]

[0064] Second, sulfone compounds that generate sulfonic acid can be mentioned, and specific compounds thereof are exemplified below.

[0065] [Chemical 6]

[0066] Thirdly, a halide that photo-generates halogen hydrogen can also be used, and specific compounds thereof are exemplified below.

[0067] [Chemical 7] CONHCOCCI,

OOCH, CCI

[0068] Fourthly, an iron allene complex can be mentioned.

[0069] [Chemical 8]

[0070] The actinic ray curable inkjet ink of the present invention (hereinafter also simply referred to as inkjet ink or ink) contains various known pigments together with the actinic ray curable composition described above.

[0071] Pigments that can be preferably used in the present invention are listed below.

[0072] CI Pigment Yellowl, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 81, 83, 8 7, 93, 95, 97, 98, 109, 114, 120, 128, 129, 138, 150, 151, 154, 180, 1 85C.I. Pigment Red5, 7, 12, 22, 38, 48: 1, 48: 2, 48: 4, 49: 1, 53: 1, 57: 1, 63: 1, 101, 112, 122, 123, 144, 146, 168, 184, 185, 202C. I. Pigme nt Violet 19, 23C. I. Pigment Bluel, 2, 3, 15: 1, 15: 2, 15: 3, 15: 4, 18, 22, 27, 29, 60C. I. Pigment Green7, 36C. I. Pigment White6, 18, 21C I. Pigment Black7

In addition, in the ink of the present invention, it is preferable to use white ink in order to improve the color concealability on a transparent substrate such as a plastic film. In particular, white ink is preferably used in soft packaging printing and label printing.

[0073] For the dispersion of the pigment, for example, a ball mill, sand mill, attritor, roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, paint shaker, or the like can be used. Further, a dispersing agent can be added when dispersing the pigment. As the dispersant, it is preferable to use a polymer dispersant, for example, Solsperse series by Avecia and PB series by Ajinomoto Fine Techno. In addition, a synergist according to various pigments can be used as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment. Although the dispersion medium is a solvent or a polymerizable compound, the radiation curable ink used in the present invention is preferably solvent-free because it is reacted and cured immediately after ink deposition. If the solvent remains in the cured image, the solvent resistance deteriorates and the VOC problem of the remaining solvent occurs. Therefore, the dispersion medium is not a solvent but a polymerizable compound, and it is preferable to select a monomer having the lowest viscosity in view of dispersibility.

[0074] The pigment dispersion is preferably such that the average particle size of the pigment particles is 0.08 to 0.5 μm, and the maximum particle size is 0.3 to: LO / zm, preferably 0.3. Appropriately set the pigment, dispersant, dispersion medium selection, dispersion conditions, and filtration conditions to be ~ 3 m. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

In the ink of the present invention, the color material concentration is 1% by mass to 10% by mass of the whole ink.

% Is preferred.

[0076] Various additives other than those described above can be used in the actinic ray curable inkjet ink of the present invention. For example, surfactants, leveling additives, matting agents, polyester-based resins, polyurethane-based resins, vinyl-based resins, attaric-based resins, rubber-based resins, waxes for adjusting film properties Can be added. In the ink of the present invention, the viscosity at 25 ° C. is preferably 7 to 50 mPa ′s in order to obtain good curability. The viscosity in the present invention is a value of a shear rate of 1000 (lZs) measured with a viscoelasticity measuring apparatus MCR300 manufactured by Physica.

[0078] As the recording material that can be used in the present invention, in addition to ordinary uncoated paper, coated paper, and the like, various non-absorbable plastics used for so-called flexible packaging and films thereof can be used. Examples of films include polyethylene terephthalate (PET) film, stretched polystyrene (OPS) film, stretched polypropylene (OPP) film, stretched nylon (ONy) film, polychlorinated butyl (PVC) film, polyethylene (PE). Examples thereof include a film and a triacetyl cellulose (TAC) film. Other plastics that can be used include polycarbonate, acrylic resin, ABS, polyacetal, polyvinyl alcohol, and rubbers. It can also be applied to metals and glass.

[0079] The surface energies of these various plastic films differ greatly, and the dot strength after ink landing varies depending on the recording material, so that the conventional force has also been a problem. With the configuration of the present invention, good high-definition images are formed on a wide range of recording materials with a surface energy of 35 to 60 mNZm, including OPP films with low surface energy, OPS films, relatively large surface energy, and even PET. it can.

[0080] In the present invention, a long (web) recording material is used in terms of the cost of recording materials such as packaging costs and production costs, print production efficiency, and compatibility with various sizes of prints. Is more advantageous.

Next, the image forming method of the present invention will be described.

[0082] In the image forming method of the present invention, the ink of the present invention is ejected and drawn on a recording material by an ink jet recording method, and then irradiated with actinic rays such as ultraviolet rays to harden the ink. .

[0083] (Total ink film thickness after ink landing)

In the present invention, the total ink film thickness after the ink has landed on the recording material and cured by irradiation with actinic rays is preferably 2 to 20 m. In the actinic ray curable inkjet recording in the field of screen printing, the total ink film thickness currently exceeds 20 m. Recording materials are often thin and plastic materials. In the flexible packaging printing field, not only the above-mentioned curling and wrinkle problems of recording materials, but also changes in the overall print material's stiffness and texture can cause problems. Therefore, it is preferable to discharge ink with excessive film thickness.

[0084] Here, "total ink film thickness" means the maximum value of the film thickness of ink drawn on the recording material, and even for a single color, other two color layers (secondary colors) or three color layers Even when recording is performed with the four-color superposition (white ink base) inkjet recording method, the meaning of the total ink film thickness is the same.

[0085] (Ink ejection conditions)

As the ink ejection conditions, it is preferable from the viewpoint of ejection stability that the inkjet recording head and the actinic radiation curable ink jet ink are heated to 35 to: LOO ° C. to eject the actinic radiation curable inkjet ink. Actinic ray curable ink-jet ink has a large viscosity fluctuation range due to temperature fluctuation, and the viscosity fluctuation directly affects the droplet size and droplet ejection speed, causing image quality degradation. Must be kept constant. The control range of the ink temperature is set temperature ± 5 ° C, preferably set temperature ± 2 ° C, more preferably set temperature ± 1 ° C.

[0086] In the present invention, it is preferable that the amount of ink droplets discharged from each nozzle of the ink jet recording head is 2 to 15 pl! /.

[0087] Originally, in order to form a high-definition image, it is necessary that the ink droplet amount force S be in this range. However, when discharging with this ink droplet amount, the aforementioned discharge stability becomes particularly severe. . According to the present invention, even when ejection is performed with a small droplet amount such as 2 to 15 pl, the ejection stability is improved and a high-definition image can be stably formed.

[0088] (Light irradiation conditions after ink landing)

The image forming method of the present invention is characterized in that, as an irradiation condition of active light, active light is irradiated for 0.001 seconds to 1.0 seconds after the ink has landed on the recording material. More preferably, it is 0.001 seconds to 0.5 seconds. In order to form a high-definition image, it is particularly important that the irradiation timing is as fast as possible.

[0089] A basic method of actinic ray irradiation is disclosed in JP-A-60-132767. According to this, light sources are provided on both sides of the head unit, and the head is And scan the light source. Irradiation is performed after a certain period of time after ink landing. Further, the curing is completed by another light source that is not driven. U.S. Pat.No. 6,145,979 discloses a method using an optical fiber and a method of irradiating a recording unit with ultraviolet rays by applying a collimated light source to a mirror surface provided on the side of the head unit. ing . Any of these irradiation methods can be used in the image forming method of the present invention.

[0090] In addition, the irradiation of actinic rays is divided into two stages. First, after the ink has landed, actinic rays were irradiated by the above-mentioned method for 0.001 to 2.0 seconds, and then after the completion of all printing, A method of irradiating actinic rays is also a preferred embodiment. By dividing the irradiation of actinic rays into two stages, it becomes possible to suppress the shrinkage of the recording material that occurs during ink curing.

In the image forming method of the present invention, the power with which a conventionally known high-pressure mercury lamp, methanol halide lamp, electrodeless lamp, or the like can be used as the active light is not limited thereto.

Next, the ink jet recording apparatus (hereinafter simply referred to as a recording apparatus) of the present invention will be described.

Hereinafter, the recording apparatus of the present invention will be described with reference to the drawings as appropriate. Note that the recording apparatus in the drawings is merely one aspect of the recording apparatus of the present invention, and the recording apparatus of the present invention is not limited to this drawing.

FIG. 1 is a front view showing a main configuration of the ink jet recording apparatus of the present invention.

The recording apparatus 1 includes a head carriage 2, a recording head 3, an irradiation unit 4, a platen unit 5, and the like. In this recording apparatus 1, a platen unit 5 is installed under the recording material P. The platen part 5 has a function of absorbing ultraviolet rays and absorbs excess ultraviolet rays that have passed through the recording material P. As a result, a high-definition image can be reproduced very stably.

The recording material P is guided by the guide member 6 and moves from the front side to the back side in FIG. 1 by the operation of the conveying means (not shown). Head scanning means (not shown) scans the recording head 3 held by the head carriage 2 by reciprocating the head carriage 2 in the Y direction in FIG.

[0096] The head carriage 2 is installed on the upper side of the recording material P, and a plurality of recording heads 3, which will be described later, are arranged on the lower side according to the number of colors used for image printing on the recording material P. Storage To do. The head carriage 2 is installed on the main body of the recording apparatus 1 in such a manner that it can reciprocate in the Y direction in FIG. 1, and reciprocates in the Y direction in FIG. 1 by driving the head scanning means.

In FIG. 1, the head carriage 2 is white (W), yellow (Y), magenta (M), cyan (C), black (K), light yellow (Ly), light magenta (Lm), and light cyan. (Lc), light black (Lk), and white (W) should be drawn as containing the recording head 3! /, And the color of the recording head 3 stored in the head carriage 2 when performing 1S. The number is determined as appropriate.

The recording head 3 has a discharge means (not shown) provided therein with a plurality of actinic ray curable inks (for example, ultraviolet curable ink-jet ink) supplied by an ink supply means (not shown). )) Is discharged toward the discharge locus recording material P. The ultraviolet curable ink jet ink ejected by the recording head 3 is composed of a coloring material, a polymerizable monomer, an initiator, and the like, and the initiator acts as a catalyst when irradiated with ultraviolet rays. It cures by crosslinking and polymerization reaction of monomers.

[0099] The recording head 3 has a certain area in the recording material P during the scan in which it moves from one end of the recording material P to the other end of the recording material P in the Y direction in FIG. UV ink is ejected as ink droplets to (landing possible area), and ink droplets are landed on the landing possible area.

[0100] After the above-mentioned scanning is performed as many times as necessary, and ultraviolet curable ink jet ink is ejected toward one landable area, the recording material P is appropriately moved from the near side to the far side in FIG. Then, while scanning by the head scanning means is performed again, the recording head 3 discharges the ultraviolet curable ink-jet ink to the next landable area adjacent to the depth direction in FIG.

[0101] The above operation is repeated, and the ultraviolet curable inkjet ink droplets are discharged onto the recording material P by ejecting the ultraviolet curable inkjet ink from the recording head 3 in conjunction with the head scanning means and the conveying means. An image is formed.

The irradiation means 4 includes an ultraviolet lamp that emits ultraviolet light in a specific wavelength region with stable exposure energy and a filter that transmits ultraviolet light of a specific wavelength. here As the UV lamp, mercury lamp, metal halide lamp, excimer laser, UV laser, cold cathode tube, black light, LED (light emitting diode), etc. can be applied. A mercury lamp or black light is preferred. In particular, a low-pressure mercury lamp, a cold cathode tube, a hot cathode tube, and a germicidal lamp that emit ultraviolet light having a wavelength of 254 nm are preferable because they can prevent bleeding and efficiently control the dot diameter. By using black light as the radiation source of the irradiation means 4, the irradiation means 4 for curing the ultraviolet curable ink jet ink can be produced at a low cost.

[0103] The irradiation means 4 is a recording device (ultraviolet irradiation type ink jet printer) 1 among the landable areas in which the recording head 3 ejects the ultraviolet ray curable ink jet ink by one scan by driving the head scanning means. It has almost the same shape as the maximum that can be set, or a shape that is larger than the landable area.

The irradiation means 4 is installed on both sides of the head carriage 2 so as to be fixed substantially parallel to the recording material P.

[0105] As described above, as a means for adjusting the illuminance of the ink discharge portion, not only the entire recording head 3 is shielded, but in addition, the recording head is determined by the distance hi between the irradiation means 4 and the recording material P. It is effective to reduce the distance h2 between the ink ejection section 31 and the recording material P in Fig. 3 (hi> h2), or to increase the distance d between the recording head 3 and the irradiation means 4 (increase d). is there. Further, it is more preferable that the space between the recording head 3 and the irradiation means 4 is a bellows structure 7.

Here, the wavelength of the ultraviolet rays irradiated by the irradiation means 4 can be appropriately changed by replacing the ultraviolet lamp or filter provided in the irradiation means 4.

[0107] The ink of the present invention has very excellent ejection stability and is particularly effective when an image is formed using a line head type recording apparatus.

FIG. 2 is a top view showing another example of the configuration of the main part in the ink jet recording apparatus of the present invention.

The ink jet recording apparatus shown in FIG. 2 is called a line head system, and a plurality of recording heads 3 of each color are fixed to the head carriage 2 so as to cover the entire width of the recording material P. Has been placed.

[0110] On the other hand, on the downstream side of the head carriage 2, the full width of the recording material P is also covered. Thus, irradiation means 4 is provided.

In this line head system, the head carriage 2 and the irradiation means 4 are fixed, and only the recording material P is conveyed, and ink ejection and curing are performed to form an image.

Example

Examples of the present invention will be specifically described below, but the embodiments of the present invention are not limited to these examples.

[0113] << Preparation of Pigment Dispersions 1-5 >>

Pigment dispersions 1 to 5 were prepared by dispersing each pigment with the following composition. The following two compounds were placed in a stainless beaker and dissolved by stirring and heating for 1 hour while heating on a 65 ° C hot plate.

PB822 (Ajinomoto Fine Technone Earth Dispersant) 9 parts Tetraethylene glycol ditalylate (bifunctional) 71 parts

After cooling to room temperature, add 20 parts of each of the following pigments to each glass, put it in a glass bottle together with 200 g of zirconia beads with a diameter of 0.5 mm, seal it with a paint shaker, disperse it for the following time, and then zirconia beads. The pigment dispersions 1 to 5 containing the pigments 1 to 5 were prepared.

[0114] Pigment l: Pigment Black 7 (Mitsubishi Chemical Corporation, # 52) 10 hours

Pigment 2: Pigment Blue 15: 4 (Dai-Nei Seiki Co., Ltd., Blue No. 32)

6 hours

Pigment 3: Pigment Yellow 180 (made by Dainichi Seika Co., Ltd., special order) 10 hours

Pigment 4: Pigment Red 122 (manufactured by Dainichi Seika Co., Ltd.) 10 hours

Pigment 5: Titanium oxide (anatase type: particle size 0.2 m) 10 hours

Composition powers listed in Tables 1 to 6 Ink strengths as described Invented ink sets 1 to 6 were prepared and filtered through a Teflon (registered trademark) 3 μm membrane filter manufactured by A DVATEC.

[0115] The viscosity of each color ink of each ink set prepared above is as follows. Viscosity is the value of shear rate 1000 (lZs) measured with a viscoelasticity measuring device MCR300 manufactured by Physica at 25 ° C. expressed.

Ink set 1:: 30 -33mPa- s Ink set 2:: 28 -33mPa- s Ink set 3:: 31 '35mPa' s Ink set 4:: 21 '26mPa' s ink set 5:: 27 30mPa 's ink Set 6:: 26 31mPa 's

[0117] [Table 1]

[0118] [Table 2]

Ink composition (mass%)

Basic photo radical Photo acid Colorant Photopolymerizable compound

Compound Generator Generator Generator Ink

氺 E 1 氺 A * E 2 * 0X

Type Pigment UVI Type OXT * 1 1-1850

Dispersion EP- 6 A-2 A— 3 S2021P 6992

221

Ink K Pigment 1 12.5 15.0 10.9 20.0 15.0 20.0 0.10 2.5 4.0 Set 2 C Pigment 2 12.5 15.0 10.9 20.0 15.0 20.0 0.10 2.5 4.0 (Invention) M Pigment 4 21.0 15.0 2.4 20.0 15.0 20.0 0.10 2.5 4.0

Y pigment 3 15.0 15.0 8.4 20.0 15.0 20.0 0.10 2.5 4.0

W Pigment 5 40.0 15.0 3.4 20.0 15.0 20.0 0.10 2.5 4.0

Lk pigment 1 3.1 15.0 20.3 20.0 15.0 20.0 0.10 2.5 4.0 c pigment 2 3.1 15.0 20.3 20.0 15.0 20.0 0.10 2.5 4.0 m pigment 4 5.3 15.0 18.2 20.0 15.0 20.0 0.10 2.5 4.0

Ly pigment 3 3.8 15.0 19.7 20.0 15.0 20.0 0.10 2.5 4.0

[0119] [Table 3] Ink composition (mass%)

[0120] [Table 4] Ink composition (mass%)

Basic interface Photoradical Photoacid Colorant Photopolymerizable compound

Compound activator generator generator generator ink

* E 2 氺 0X

Type Pigment KF-UVI Ink Type 0XT 0XT * 3 1-907

Dispersion S3000 352 6976 Set 4 221 212

(Comparative example) K pigment 1 12.5 35.0 34.8 10.0 0.10 0.10 2.5 5.0

C Pigment 2 12.5 35.0 34.8 10.0 0.10 0.10 2.5 5.0

M Pigment 4 21.0 35.0 26.3 10.0 0.10 0.10 2.5 5.0

Y Pigment 3 15.0 35.0 32.3 10.0 0.10 0.10 2.5 5.0

W Pigment 5 40.0 35.0 7.3 10.0 0.10 0.10 2.5 5.0

[0121] [Table 5]

[0122] [Table 6]

[0123] The details of each compound described in abbreviations in Table 16 are as follows. [0124] [Ink type]

K: Dark black ink c: Dark cyan ink

M: Dark magenta ink

Y: dark yellow ink

W: White ink

Lk: Light black ink

Lc: Light cyan ink

Lm: Light magenta ink

Ly: Light yellow ink

(Pigment type)

Pigment 1: C. I. pigment Black 7

Pigment 2: C. I. pigment Blue 15: 4

Pigment 3: C.I.pigment Yellow 180

Pigment 4: C. I. pigment Red 122

Pigment 5: Titanium oxide (anatase type average particle size 0.20 μm)

[Photopolymerizable compound]

<* A: Atarireich compound>

A1: Lauryl acrylate (monofunctional)

A2: Tetraethylene glycol ditalylate (bifunctional)

A3: Force prolatatam modified dipentaerythritol hexaatalylate (hexafunctional) <* E1: New alicyclic epoxy compound>

EP--1: Exemplary compound EP- 1

EP--3: Exemplary compound EP-3

EP- -4: Exemplary compound EP--4

EP--5: Exemplary compound EP-5

EP- -6: Exemplary compound £? -6

<* E2: Alicyclic epoxy compound>

S2021P: Celoxide 2021P (manufactured by Daicel Chemical Industries)

S3000: Celoxide 3000 (manufactured by Daicel Chemical Industries) 9

<* OX: Oxetane compound>

OXT-101: Toagosei Co., Ltd.

OXT -212: Toagosei Co., Ltd.

OXT-221: Made by Toagosei

RSOX: Toagosei Co., Ltd.

<* Ml: Compound containing maleimide skeleton>

MIA200: LUMICURE MIA200 (manufactured by Dainippon Ink & Chemicals, Inc.) <PE: Polyene compound>

PE1: triallyl metaisocyanurate (Nippon Kasei Co., Ltd.)

<* PT: Polythiol compound>

PT1: Trimethylolpropane tristiodalycolate (manufactured by Sakai Chemical Co., Ltd.)

[Photoradical generator]

1-184: Irgacure 184 (manufactured by Ciba Specialty Chemicals) 1—369: Irgacure 369 (manufactured by Chinoku Specialty Chemicals) 1-907: Inoregacure 907 (Ciba Specialty Chemicals) 1-1800: Irgacure 1800 (Chinoku Specialty Chemicals) 1-1850: Irgacure 1850 (Chinoku Specialty Chemicals) 1— 2959: Irgacure 2959 (Chinoku Specialty) (Made by Charity Chemicals) (Basic compounds)

* 1: Triisopropanolamine

* 2: N-ethyldiethanolamine

* 3: Tributinoleamine

[Photoacid generator] UVI6976: UVI6976 (Propylene carbonate 50% solution Dow Chemical Co.) UVI6992: UVI6992 (Propylene carbonate 50% solution Dow Chemical Co.) DST-102: DST-102 (Midori Chemical Co.)

SP152: SP152 (Propylene carbonate 50% solution manufactured by Asahi Denka Kogyo Co., Ltd.) C9000: Chivacure9000 (Propylene carbonate 50% solution manufactured by Chitec) [Surfactant]

SDX— 1843: Asahi Denki Kogyo Co., Ltd.

KF- 352: Shin-Etsu Silicone

XF42-334: Modified silicone oil, manufactured by GE Toshiba Silicone

In Tables 1 to 6, the values in the pigment column indicate the pigment number, and other values indicate mass%.

[0127] <Inkjet image forming method>

Each of the ink sets 1 to 3 prepared above was loaded into an inkjet recording apparatus having a piezo-type inkjet nozzle and having the constitutional power shown in FIG. The following image recording was continuously performed on the recording material. For image data, refer to “High-Definition Color Digital Standard Image Data“ N5 Bicycle ”(Japan Standards Association)

Issued in December 1995). The ink supply system consisted of an ink tank, a supply pipe, a front chamber ink tank just before the head, a pipe with a filter and a piezo head. The piezo head was driven to eject 2 to 15 pl multi-size dots at a resolution of 720 x 720 dpi, and each ink was ejected continuously. After landing, it is cured instantly (less than 2 seconds after landing) by the lamp units on both sides of the carriage. After recording, the total ink film thickness was measured and found to be in the range of 2.3 to 13 m. The dpi referred to in the present invention represents 2.5 dots per 54 cm. Inkjet images were formed according to the above method in an environment of 10 ° C. and 20% RH, an environment of 25 ° C., 50% RH, and an environment of 27 ° C. and 80% RH, respectively.

Further, in the same manner, an image was formed using ink sets 4 to 6 using the line head recording type inkjet recording apparatus shown in FIG.

[0129] [Table 7] Ink irradiation conditions

Sample

Set Recording material Irradiation time Illuminance on the surface of the recording material Remarks Number Irradiation light source Irradiation method

Number (after landing) raW 'cm

1 1 P E T A 0.1 second later C 300 Comparative example

2 1 P V C A 0.1 seconds later C 300 Comparison example

3 1 卜卜 Paper A 0.1 seconds later C 300 Comparison example

4 2 P E T A 0.1 seconds later C 300 The present invention

5 2 P V C A 0.1 seconds later C 300 The present invention

6 2 Key paper A 0.1 seconds later C 300 The present invention

7 3 P E T A 0.1 seconds later C 300

8 3 P V C A 0.1 seconds later C 300 The present invention

9 3 er paper A 0.1 seconds later C 300 The present invention

10 4 P E T B 0.1 seconds later D 400 Comparative example

11 4 P V C B 0.1 seconds later D 400 Comparative example

12 4 Wart paper B 0.1 seconds later D 400 Comparative example

13 5 P E T B 0.1 seconds later D 400 Present invention

14 5 P V C B 0.1 seconds later D 400 Present invention

15 5 key paper B 0.1 seconds later D 400 Present invention

16 6 P E T B 0.1 seconds later D 400 Present invention

17 6 P V C B 0.1 seconds later D 400 Present invention

18 6 First paper B 0.1 seconds later D 400 Present invention

[0130] The details of the items described in abbreviations in Table 7 are as follows.

[0131] <Recording material>

PET: polyethylene terephthalate

PVC: poly vinyl chloride

Irradiation light source A: Electrodeless lamp (Power Cure · One made by Fusion UV Systems) Irradiation light source B: 120WZcm metal halide lamp (MAL 400NL made by Nippon Battery Co., Ltd.) Also, the illumination intensity on the recording material surface of each irradiation light source listed in Table 7 is The integrated illuminance at 254 nm was measured and displayed using UVP F-A1 manufactured by Iwasaki Electric Co., Ltd.

[0132] <Irradiation method>

Irradiation method C: Irradiation from both ends of the recording head (ink jet recording apparatus shown in FIG. 1) Irradiation method D: Line light source irradiation downstream of the recording material conveyance direction (line head type ink jet recording apparatus shown in FIG. 2) <Evaluation of inkjet recording image>

Each of the images recorded under different temperature and humidity environments by the above image forming method was subjected to the following evaluations.

[0133] (Character quality)

Using each color ink of Y, M, C, and K, print 6 point MS Mincho fonts at the target density in each temperature and humidity environment, and enlarge and evaluate the character roughness with a loupe. The character quality was evaluated.

[0134] A: No roughness

◯: Slightly rough

△: Visible but can be distinguished as characters and can be used at the last minute

X: Level that can not be used due to severely blurred characters

(Mixed colors (bleeding, wrinkles))

Under each temperature and humidity environment, print at 720dpi so that each dot of Y, M, C, K colors is adjacent to each other, enlarge each adjacent color dot with a magnifying glass, visually observe the degree of bleeding, and comply with the following standards The color mixture was evaluated.

[0135] A: Adjacent dot shape keeps perfect circle and no blur

◯: Adjacent dot shape keeps almost perfect circle and almost no bleeding

△: Adjacent dots are slightly blurred and the dot shape is slightly deformed.

X: Adjacent dots are blurred and mixed, and there are wrinkles in the overlapping area.

Table 8 shows the evaluation results obtained as described above.

[0136] [Table 8] 10¾ 20½RH Z5 * C 50% H 27 ° C 80% RH

Sample

No. Color mixing Color mixing Color mixing Remarks

Character S Character quality Fumiko. . .

(Smudge, 皺) (smudge, m (smudge, thin)

1 O o ○ Δ O X Comparison

2 〇 Δ 厶 X X X Comparison

3 0 △ 厶 Δ X X Comparison

4 ◎ ◎ ◎ ◎ 〇 This invention

5 ® ◎ O ○ ○ The present invention

6 ◎ ◎ ◎ 〇 O O The present invention

7 O O o ○ ○ 0 This invention

8 O O ○ ○ ○ Δ The present invention

9 ○ ○ ○ O ○ △ The present invention to o ○ o △ O X Comparison

1 1 o ○ 厶 X X X ratio

12 o 〇厶厶 X X Compare

14 ○ O ○ o 0 Δ The present invention

15 ○ O o o ○ Δ The present invention

! 8 ◎ ◎ ◎ @ 〇 This invention As is clear from the results shown in Table 8, the ink set defined by the present invention is different from the comparative example regardless of the printing environment. High-definition images can be stably formed on the material.

Claims

Claims As the photopolymerizable compound, at least one selected from monofunctional alicyclic epoxy compounds represented by the following general formulas (1) to (4), a (meth) acrylate monomer and An actinic ray curable composition comprising at least one selected from oligomer power.

[Chemical 1]

—General formula (1) General formula (2)

[In the formula, R, R, R, R, R, R, R, R are each a hydrogen atom, an alkyl having 1 to 5 carbon atoms a b d e g h j k

R and R, R and R, R and R, R and R are simultaneously a b d e g h j k

Does not represent a hydrogen atom. R ~ R

An alkyl group or a substituted alkyl group is represented. ]

[2] As the photopolymerizable compound, at least one selected from monofunctional alicyclic epoxy compounds represented by the following general formulas (1) to (4) and a compound containing a maleimide skeleton: Actinic ray curable composition characterized by containing.

[Chemical 2]

R and R, R and R, R and R, R and R are simultaneously a b d e g h j k

Does not represent a hydrogen atom. R ~ R

An alkyl group or a substituted alkyl group is represented. ]

As a photopolymerizable compound, at least one selected from monofunctional alicyclic epoxy compounds represented by the following general formulas (1) to (4), a polyenic compound and a polythiol compound are included. An actinic ray curable composition characterized by comprising.

[Chemical 3]

R and R, R and R, R and R, R and R are simultaneously a b d e g h j k

Does not represent a hydrogen atom. R ~ R

c f i and R

[4] The molecular weight of the monofunctional alicyclic epoxy compound represented by the general formulas (1) to (4) is 190 or more and 300 or less. 4. The actinic ray curable composition according to any one of items 3.

[5] The actinic ray curable composition according to any one of claims 1 to 4, further comprising a compound having an oxetane ring as the photopolymerizable compound.

[6] The actinic ray curable composition according to any one of claims 1 to 5, wherein the viscosity at 25 ° C is 7 mPa's or more and 50 mPa's or less.

[7] An actinic ray curable ink jet ink, wherein the actinic ray curable composition according to any one of claims 1 to 6 contains a pigment.

[8] An image forming method in which the actinic ray curable inkjet ink according to claim 7 is ejected from an inkjet recording head onto a recording material, and printing is performed on the recording material.

After the actinic ray curable ink-jet ink has landed on the recording material, it is not less than 0.001 seconds. 1. An image forming method comprising irradiating actinic rays for 1.0 seconds or less.

[9] An image forming method in which the actinic ray curable ink jet ink according to claim 7 is ejected from an ink jet recording head onto a recording material, and printing is performed on the recording material. An image forming method, wherein the total ink film thickness is 2 m or more and 25 m or less after the ink jet ink is landed on the recording material and cured by irradiation with actinic rays.

[10] An image forming method in which the actinic ray curable inkjet ink according to claim 7 is ejected from an ink jet recording head onto a recording material, and printing is performed on the recording material. An image forming method characterized in that the volume of ink droplets discharged from each nozzle is 2 pl or more and 15 pl or less.

11. The image forming method according to any one of claims 8 to 10, wherein the ink jet recording head is a line head type.

[12] An ink jet recording apparatus for use in the image forming method according to any one of claims 8 to 11, wherein the actinic ray curable ink jet ink and the ink jet recording head are disposed at 35 ° C to 100 ° C. An ink jet recording apparatus having a mechanism for discharging the actinic ray curable ink jet ink after heating to ° C.