INK COMPOSITION, INK SET, INKJET RECORDING METHOD, PRINTED MATERIAL, METHOD FOR MANUFACTURING MOLD PRINTED MATERIAL, AND MOLD PRINTED MATERIAL
BACKGROUND OF THE INVENTION
[1] 1. Field of the Invention
[2] The present invention relates to an ink composition, an ink set, an inkjet recording method, a printed material, a method for manufacturing mold printed material, and a mold printed material..
[3] 2. Description of the Related Art
[4] An electrophotographic method, a sublimation-type and fusion-type thermal transfer method, an inkjet method, and the like are known as an image recording method of forming an image on a recording medium on the basis of an image data signal. In the inkjet method, since ink is ejected to only a necessary image part by the use of a cheap apparatus to form an image directly on a recording medium, it is possible to efficiently use an ink composition and the running cost is thus low. The inkjet method has small noise and is excellent as an image recording method.
[5] Examples of an ink composition containing a metal pigment include ink compositions described in JP2009-091550Aand JP2008-088228A.
SUMMARY OF THE INVENTION
[6] An object of the present invention is to provide an ink composition and an ink set which are excellent in curability and which can result in a metallic-gloss image having both excellent flexibility and high film hardness, an inkjet recording method using the ink composition, a printed material, a method for manufacturing mold printed material, and a mold printed material.
[7] The objects of the present invention have been accomplished by means described below.
[8] (1) An ink composition including: (Component A) an aluminum metal pigment; (Component B) a radical polymerizable compound; and (Component C) a radical photopolymerization initiator, wherein Component B includes 80 to 99.9 mass% of a monofunctional monomer and 0.1 to 20 mass% of a polyfunctional monomer in the radical polymerizable compound.

(2) The ink composition, wherein the content of Component A in the ink composition is
in the range of 0.5 to 20 mass%.
[10] (3) The ink composition according to (1) or (2), wherein a compound expressed by
Formula (b-1) and/or a compound expressed by Formula (b-2) is contained as the
monofunctional monomer:
Formula (b-1)


(where R1 represents a hydrogen atom or a methyl group, X represents a single bond, an
alkylene group, an oxyalkylene group or a group having a combination of two or more
oxyalkylene groups, an ester bond, or a group having a combination of two or more thereof, R2
and R3 independently represent a hydrogen atom or an alkyl group, R4 to R8 independently
represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or an aminoalkyl
group, at least one of R4 to R8 is a hydrogen atom, and two or more of R2 to R8 are bonded to
form a cyclic structure); and
Formula (b-2)
(where n represents an integer in the range of 1 to 5).
[11] (4) The ink composition according to (3), wherein the total content of the compound
expressed by Formula (b-1) and the compound expressed by Formula (b-2) in Component B is
in the range of 5 to 99.9 mass% of the ink composition.
[12] (5) An ink set including at least one of the ink composition according to any one of (1)
to (4) and an ink composition containing a colorant other than Component A.
[13] (6) An inkjet recording method including: an image forming step of forming an image
on a recording medium by ejecting the ink composition according to any one of (1) to (4); and
a curing step of curing the ink composition by irradiating the ejected ink composition with
active radiation and acquiring a printed material having an image cured on the recording
medium.

[14] (7) A printed material acquired using the inkjet recording method according to (6).
[15] (8) A method for manufacturing mold printed material including: an image forming step of forming an image on a recording medium by ejecting the ink composition according to any one of (1) to (4); a curing step of curing the ink composition by irradiating the ejected ink composition with active radiation and acquiring a printed material having an image cured on the recording medium; and a step of molding the printed material.
[16] (9) A mold printed material acquired using the method for manufacturing mold printed material according to (8).
[17] According to the present invention, an ink composition and an ink set which are excellent in curability and which can result in a metallic-gloss image having both excellent flexibility and high film hardness, an inkjet recording method using the ink composition, a printed material, a method for manufacturing mold printed material, and a mold printed material can be provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[18] Fig. 1 is a schematic diagram illustrating an example of a mold used in a molding test.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
I. Ink Composition
[20] An ink composition according to the present invention is preferably used for inkjet recording and includes (Component A) an aluminum metal pigment, (Component B) a radical polymerizable compound, and (Component C) a radical photopolymerization initiator. Component B includes 80 to 99.9 mass% of a monofunctional monomer and 0.1 to 20 mass% of a polyfunctional monomer in the radical polymerizable compound.
[21] In the specification, description "A to B" representing a numerical range is synonymous with "equal to or greater than A and equal to or less than B" (including A as a lower limit and B as an upper limit), as long as it is not differently mentioned. Description "(meth)acrylate" and the like is synonymous with "methacrylate and/or acrylate" and the like.
[22] The ink composition according to the present invention is an oil-based ink composition curable by active radiation. The "active radiation" is radiation that can give energy for generating initiating species in the ink composition by the irradiation thereof and examples thereof include α-rays, γ-rays, X-rays, ultraviolet rays, visible rays, and electron rays. Among these the ultraviolet rays and the electron rays are preferable in terms of curing

sensitivity and device availability, and the ultraviolet rays are more preferable. Hereinafter, the components will be described.
[23] (Component A) Aluminum Metal Pigment
[24] The ink composition according to the present invention includes (Component A) an aluminum metal pigment.
[25] Any known aluminum powder can be appropriately selected and used as aluminum powder that can be suitably used as an aluminum metal pigment.
[26] The aluminum powder may be produced by any manufacturing method. Examples of the aluminum powder producing method include a method of flatting and pulverizing aluminum metal, a method of depositing aluminum on a thin film and pulverizing the resultant, and a method of very precisely pulverizing a photoluminescent foil, but the present invention is not limited to these methods.
[27] The aluminum powder to be added may have any of a paste form or a powder form. An example of the aluminum powder having a paste form is a paste form in which aluminum powder is dispersed in a hydrocarbon-based solvent (for example, ethyl acetate).
[28] The aluminum powder used in the present invention may be subjected to surface treatment. For example, a stearic acid and the like may be adsorbed on the powder surface. When the aluminum powder processed by this method is used, the aluminum powder tends to be arranged in parallel on the surface of ejected ink, thereby acquiring a printed material having an almost specular finish.
For example, an aluminum powder may be coated with a resin. In this case, adhesion, chemical resistance, weather resistance, and the like are improved and thus the aluminum powder is preferable. On the contrary, it tends to be poor in glossiness or concealment.
[30] The aluminum powders are commercially available, and examples of a paste-form aluminum powder dispersed in a hydrocarbon-based solvent include ROTOVARIO 500 series (made by Eckart Co.) and ASTROSHINE T-8990 and ASTROSHINE T-8765 (both made by Nihonboshitsu Co., Ltd.).
[31] In the present invention, the aluminum metal pigment is preferably dispersed in the radical polymerizable compound. That is, the aluminum metal pigment is preferably dispersed not in water or a solvent but in the radical polymerizable compound.
[32] The aluminum metal pigment preferably has a volume-average particle diameter in the range of 0.05 to 1.5 μm in the ink composition, more preferably in the range of 0.10 to 1.3 μm, and yet more preferably in the range of 0.15 to 1.0 μm. When the volume-average particle

diameter is in the above-mentioned numerical range, it is possible to improve both an ejection property and a metal gloss.
[33] In the present invention, the volume-average particle diameter may be measured by the use of a laser diffraction/scattering particle size distribution analyzer (product name: Microtrac MT3300EX, made by Nikkiso Co., Ltd.) or the like by diluting the powder with a liquid such as a dispersion medium.
[34] In the present invention, the content of the aluminum metal pigment is preferably 0.5 to 20 mass% relative to the total amount (total mass) of the ink composition, more preferably in the range of 3 to 20 mass%, and yet more preferably in the range of 5 to 18 mass%.
[35] When the content of the aluminum metal pigment is equal to or greater than 0.5 mass%, a good sense of brightness is obtained, which is preferable. When the content of the aluminum metal pigment is equal to or less than 20 mass%, the ink composition has excellent stability, which is preferable.
[36] The ink composition used in the present invention is preferably a dispersion including the radical polymerizable compound, the radical photopolymerization initiator, and the aluminum metal pigment which are dispersed in a non-aqueous system.
[37] The ink composition can be prepared (made into an ink) by, for example, adding the radical polymerizable compound, the radical photopolymerization initiator, the aluminum metal pigment, and various additives as necessary.
[38] In the present invention, it is preferable to use a dispersant to prepare the ink composition, and it is more preferable to use an acidic dispersant as the dispersant.
The ink composition may be prepared by first preparing a dispersion having a high concentration of the aluminum metal pigment and diluting the dispersion by adding the radical polymerizable compound, various additives, and the like.
[40] To disperse the aluminum metal pigment, dispersion instruments such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, and a wet jet mill can be used.
[41] In the present invention, it is preferable to finely disperse at least the aluminum metal pigment, the radical polymerizable compound, and the dispersant by the use of beads (dispersion media) at the time of carrying out dispersion. As a dispersion instrument, a ball mill, an agitator mill, a paint shaker, and the like may be used.
[42] Examples of the beads (dispersion media) include glass beads, stainless steel beads,

alumina beads, and zirconia beads. Among these, it is preferable to use zirconia beads as the beads (dispersion media). The zirconia beads are preferable, since they have excellent strength and hardness and generate little powder at the time of cutting the beads (dispersion media).
[43] When the aluminum metal pigment is dispersed as described above, it is preferable to add a dispersant thereto.
[44] In the present invention, it is preferable to use an acidic dispersant as the dispersant. The acidic dispersant means a polymer compound having an acidic pigment hydrophilic group at an terminus of the main chain by means of a block or graft structure. When the acidic dispersant is used, the aluminum metal pigment is rapidly dispersed to acquire a stable dispersion, which is preferable.
[45] Examples of the acidic pigment hydrophilic group include a carboxy group, a sulfonic acid group, and a phosphoric acid group.
[46] Examples of the polymer include poly(meth)acrylate, polyurethane, polyester, and modified products thereof.
[47] These dispersants are commercially available, and examples thereof include DISPERBYK-102, DISPERBYK-110, DISPERBYK-111, DISPERBYK-112, and DISPERBYK-180 (all made by BYK-Chemie Co.) and Solsperse 26000, Solsperse 36000, and Solsperse 41000 (all made by Lubrizol Corporation). The dispersants may be used singly or in a combination of two or more examples.
[48] In the ink composition, a solvent may be added as a dispersion medium for various components of the aluminum metal pigment. Alternatively, the radical polymerizable compound which is a low molecular-weight component may be used as a dispersion medium without using a solvent. In the present invention, since the ink composition is a radiation-curing ink composition and is cured after the ink composition is applied to a recording medium, it is preferable that the ink composition be solventless or is a low solvent ink.
From the viewpoint of improvement in dispersibility, it is preferable that the structure of the radical polymerizable compound used as a dispersion medium include an ethylene oxide (EO) chain, a propylene oxide (PO) chain, and a benzene ring. In terms of curability, it is preferable that the structure has a polymerizable group.
[50] Particularly preferable examples of the dispersion medium having the EO chain include Methylene glycol divinylether (RAPI-CURE DVE-3, made by ISP Japan Ltd.), polyethylene

glycol di(meth)acrylale, 2-(2-ethoxy ethoxy)-ethylacrylate (EOEOEA), and ethoxylated trimethylolpropane triacrylate (EOTMPTA).
[51] Examples of the dispersion medium having the PO chain include tripropylene glycol methylether, polypropylene glycol diacrylate, propoxylated neopentyl glycol diacrylate (NPGPODA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), and alkoxylated tetrahydrofurfuryl acrylate (CD611, made by Sartomer Company Inc.).
[52] Examples of the dispersion medium having the benzene ring include phenoxyethyl acrylate (PEA) and phenoxyethyloxyehtyl acrylate (EBECRYL110, made by Daicel-Cytec Co., Ltd.).
[53] (Component B) Radical Polymerizable Compound
[54] The ink composition according to the present invention includes (Component B) a radical polymerizable compound. Component B includes 80 to 99.9 mass% of a monofunctional monomer and 0.1 to 20 mass% of a polyfunctional monomer in the radical polymerizable compound.
[55] Monofunctional Monomer
[56] The ink composition according to the present invention includes a monofunctional monomer as the radical polymerizable compound. The monofunctional monomer occupies 80 to 99.9 mass% of the total mass of Component B.
[57] When the content of the monofunctional monomer in Component B is less than 80 mass%, the flexibility of the cured film is deteriorated. In terms of the curability of the ink composition, the flexibility of the cured film, and the film hardness, it is preferable that the content of the monofunctional monomer is in the range of 82 to 98.0 mass%.
[58] A compound having a radical-polymerizable ethylenically-unsaturated group in a molecule is preferably used as the monofunctional monomer and a compound having an ethylenically-unsaturated group selected from the group consisting of a (meth)acrylate group, a (meth)acrylamide group, a vinyloxy group, and an N-vinyl group is more preferably used. By including such a monofunctional monomer, it is possible to obtain an image which is excellent in curability and flexibility.
Examples of the monofunctional monomer include compounds expressed by Formula (b-1), compounds expressed by Formula (b-2), and aromatic monofunctional monomers.
[60] Compound Expressed by Formula (b-1)
[61] The ink composition according to the present invention preferably include a compound

I i
expressed by Formula (b-1). By including the compound expressed by Formula (b-1), it is
possible to improve the dispersion stability, to enhance the aluminum ratio on the surface of an
ink membrane, and thus to obtain an ink composition which can form an image with high
curability and film hardness.
[62] Formula (b-1)

[63] In Formula (b-1), R1 represents a hydrogen atom or a methyl group, X represents a
single bond, an alkylene group, an oxyalkylene group or a group having a combination of two
or more oxyalkylene groups, an ester bond, or a group having a combination of two or more
thereof, R2 and R3 independently represent a hydrogen atom or an alkyl group, R4 to R8
independently represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or
an aminoalkyl group, at least one of R4 to R8 is a hydrogen atom, and two or more of R2 to R8
are bonded to form a cyclic structure.
[64] In Formula (b-1), R1 represents a hydrogen atom or a methyl group and preferably a
hydrogen atom.
[65] X represents a single bond, an alkylene group, an oxyalkylene group or a group having
a combination of two or more oxyalkylene groups, an ester bond, or a group having a
combination of two or more thereof.
[66] The carbon number of the alkylene group is preferably in the range of 1 to 10 and more
preferably in the range of 1 to 8.
[67] The oxyalkylene group or the group having a combination of two or more oxyalkylene
groups is a group in which the alkylene group side is bonded to an oxygen atom of a
(meth)acryloyloxy group in Formula (b-1). An alkylene group having a carbon number of 1
to 5 and having a straight chain or a branch can be preferably used as the alkylene group
included in the oxyalkylene group, an alkylene group having a carbon number of 2 or 3 and
having a straight chain or a branch can be more preferably used, and an isopropylene group
can be yet more preferably used. When two or more oxyalkylene groups are combined, the
number of oxyalkylene groups is preferably equal to or less than 10 and more preferably equal
to or less than 5.
[68] When X includes an ester bond (-COO- or -OCO-), X is preferably a group obtained
by combining the alkylene group and the ester bond. That is, it is preferably an

oxycarbonylalkylene group in which an oxygen group is bonded to a carbon atom to which R2 and R3 are bonded.
R2 and R3 independently represent a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group having a carbon number of 1 to 3, and more preferably a hydrogen atom or a methyl group.
[70] R4 to R8 independently represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or an aminoalkyl group.
[71] The alkyl group is preferably an alkyl group having a carbon number of 1 to 10 and having a straight chain or a branch.
[72] The alkoxy group is preferably an alkoxy group having a carbon number of 1 to 5 and having a straight chain or a branch and more preferably a methoxy group.
[73] The amino group includes an amino group, a monoalkylamino group, and a dialkylamino group. The alkyl group is preferably an alkyl group having a carbon number of 1 to 3 and having a straight chain or a branch. The amino group is preferably a dimethylamino group, a diethylamino group, or a diisopropylamino group.
[74] An amino group included in the aminoalkyl group is the same as the above-mentioned amino group. That is, the aminoalkyl group includes a monoalkylamino group and a dialkylamino group. The part of the alkyl group other than the amino group of the aminoalkyl group is preferably an alkyl group having a carbon number of 1 to 3. The aminoakyl group is preferably a dimethylaminomethyl group, a diethylaminomethyl group, or a diisopropylaminomethyl group.
[75] At least one of R4 to R8 is a hydrogen atom. Since at least one of R4 to R8 is a hydrogen atom, it is possible to obtain an ink composition having excellent curability.
[76] Two or more of R2 to R8 may be bonded to form a cyclic structure. When a cycle is formed, R2 to R8 forming a ring are alkyl groups. The ring is preferably a ring formed by bonding R4 or R5 and any one of R to R to each other, more preferably a cyclic ether group having a number of ring members of 4 to 6, and yet more preferably a cyclic ether group having a number of ring members of 5, that is, a tetrahydrofurfuryl group.
[77] R2 or R3 and any one of R6 to R8 may be bonded to form a cyclic structure. In this case, one of R6to R8 is preferably an alkoxy group.
[78] The formed cyclic structure is preferably a cyclic structure including two oxygen atoms and having the number of ring members of 6 to 8, more preferably a cyclic structure having the number of ring members of 6, and yet more preferably a l,3-dioxane-5-yl group.

The compound expressed by Formula (b-1) preferably has a tetrahydrofurfuryl group in
terms of curability, and a compound expressed by Formula (b-1-1) is more preferable.
[80] Formula (b-1-1)

[81] In Formula (b-1-1), R1 represents a hydrogen atom or a methyl group and X represents
a single bond, an alkylene group, an oxyalkylene group or a group having a combination of
two or more oxyalkylene groups, an ester bond, or a group having a combination of two or
more thereof.
[82] X is the same as in Formula (b-1) and the preferable range thereof is also the same.
[83] Specific examples of the compound expressed by Formula (b-1) are described below,
but the compound is not limited to the specific examples. In the examples, R represents a
hydrogen atom or a methyl group.
[84] Formulas B-1 to B-12

[85] Formulas B-13 to B-21


[86] The ink composition according to the present invention preferably include a compound
expressed by Formula (b-2).
[87] Formula (b-2)

[88] In Formula (b-2), n represents an integer in the range of 1 to 5.
In Formula (b-2), n represents an integer in the range of 1 to 5. In terms of flexibility
of the ink composition after being cured, adhesion to a recording medium, and availability of
the raw materials, n is preferably an integer in the range of 2 to 4, more preferably 2 or 4, and
yet more preferably 4, that is, an N-vinylcaprolactam. The N-vinylcaprolactam is excellent
in safety, generally used, and available at a relatively low cost, and provides excellent ink
curability and excellent adhesion of a cured film to a recording medium, which is preferable.
[90] In Component B, the total content of the compound expressed by Formula (b-1) and
the compound expressed by Formula (b-2) are preferably in the range of 5 to 99.9 mass%,
more preferably in the range of 8 to 80 mass%, and yet more preferably in the range of 10 to
60 mass%. When the total content is in the above-mentioned numerical range, the curability,
the film hardness, and the metallic gloss are excellent.
[91] Aromatic Monofunctional Monomer
[92] The ink composition according to the present invention preferably includes an aromatic
monofunctional monomer as the monofunctional monomer. It is possible to acquire an ink
composition having excellent curability by using the aromatic monofunctional monomer and

T (
the compound expressed by Formula (b-1) or the compound expressed by Formula (b-2).
[93] The aromatic monofunctional monomer is preferably a monomer having a
radical-polymerizable ethylenically-unsaturated group and at least one aromatic group in a
molecule and more preferably a monomer having a (meth)acryloyloxy group or
(meth)acrylamide group and at least one aromatic hydrocarbon group in a molecule.
[94] Specific examples of the aromatic monofunctional monomer include aromatic
monofunctional radical polymerizable monomers described in Paragraphs 0048 to 0063 of
JP2009-096985A. Among these, compounds expressed by Formula (b-3) can be preferably
used as the aromatic monofunctional radical polymerizable monomers.
[95] Formula (b-3)

[96] hi Formula (b-3), R1 represents a hydrogen atom or a methyl group, X1 represents a
divalent linking group, Ar represents an aromatic hydrocarbon group, R5 represents a
substituent, u represents an integer in the range of 0 to 5, and u R5's may be equal to or
different from each other.
[97] In Formula (b-3), R1 is preferably a hydrogen atom.
[98] X1 represents a divalent linking group and is preferably an ether group (-O-), an ester
group (-C(O)O- or -OC(O)-), an amide group (-C(O)NR'-), a carbonyl group (-C(O)-), an
imide group (-NR'-), an alkylene group having a carbon number of 1 to 15 which may have a
substituent, or divalent groups formed by combining two or more thereof. R' represents a
hydrogen atom, an alkyl group having a carbon number of 1 to 20 and having a straight chain,
a branch, or a ring, or an aryl group having a carbon number of 6 to 20.
In Formula (b-3), a terminus bonded to a vinyl group of X1 is preferably an ester group
or an amide group in which a carbon of a carbonyl group of X1 is bonded to an
ethylenically-unsaturated group and more preferably an ester bond. Particularly, the terminal
preferably has a structure of H2C=(C(R1)-C(O)O-. In this case, the other part of X1 may be a
single bond or a group arbitrarily selected from the above-mentioned groups.
[100] The part (H2C=C(R1)-X1-) including R1 and X1 can be bonded at any position of the
aromatic hydrocarbon group Ar.
[101] In terms of improvement of affinity with a colorant, the terminus bonded to the
aromatic hydrocarbon group Ar of X1 is preferably an oxygen atom and more preferably an
ethereal oxygen atom, and X1 is preferably *-C(O)O(LO)q- or *-C(O)NH(LO)q-. Here, *

represents a bonding position of X1 in Formula (A2) and an ethylenically-unsaturated group, q represents an integer in the range of 0 to 10, and L represents an alkylene group having a carbon number of 2 to 4. X1 is preferably *-C(O)O(LO)q-, and q is preferably an integer in the range of 0 to 4, more preferably an integer in the range of 0 to 2, and yet more preferably 1 or 2. (LO)q is preferably an ethylene oxide chain or a propylene oxide chain.
[102] The u R5's are independently preferably a hydroxyl group, a substituted or unsubstituted amino group, a thiol group, a siloxane group, or a hydrocarbon group or a heterocyclic group having a total carbon number equal to or less than 30 which may have a substituent.
[103] Here, u represents an integer in the range of 0 to 5 and is preferably 0.
[104] Ar represents an aromatic hydrocarbon group. An example of the aromatic hydrocarbon group is monocyclic or polycyclic hydrocarbon groups having 1 to 4 rings and specific examples thereof include groups obtained by removing one or more hydrogen atoms from benzene, naphthalene, anthracene, lH-indene, 9H-fluorene, lH-phenalene, phenanthrene, triphenylene, pyrene, naphthacene, tetraphenylene, biphenylene, as-indacene, s-indacene, acenaphthylene, fluoranthene, acephenanthrylene, aceanthrylene, chrysene, pleiadene, and the like.
[105] Among these, a phenyl group and a naphtha group are preferable in the present invention, and a monocyclic hydrocarbon group, that is, a phenyl group, is more preferable.
[106] The aromatic hydrocarbon group Ar in Formula (b-3) may be an aromatic heterocycle including a hetero atom such as O, N, and S, but preferably does not include any hetero atom.
[107] In the present invention, 2-phenoxyethyl acrylate can be preferably used as the compound expressed by Formula (b-3).
[108] Other Monofunctional Monomers
The ink composition according to the present invention may include additional monofunctional monomers, in addition to the compound expressed by Formula (b-1), the compound expressed by Formula (b-2), and the aromatic monofunctional monomer. The additional monofiinctional monomers are preferably (meth)acrylic ester compounds.
[110] The (meth)acrylic ester compounds having chemical forms such as monomer, oligomer, and polymer. The additional (meth)acrylic ester compounds may be used alone or in a combination of two or more types at any ratio in order to improve desired characteristics.
[111] Specific examples thereof include monofunctional compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate,

n-nonyl (meth)acrylate, n-decyl (meth)acrylate, isooctyl (meth)acrylate, n-lauryl (meth)acrylate, n-tridecyl (meth)acryla±e, n-cetyl (meth)acrylate, n-stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantly (meth)acrylate, vinyl (meth)acrylate, allyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylaie, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, (poly)ethylene glycol mono(meth)acrylate, (poly)ethylene glycol (meth)acrylate methylester, (poly)ethylene glycol (meth)acrylate ethylester, (polypropylene glycol mono(meth)acrylaie, (poly)propylene glycol (meth)acrylate methylester, (polypropylene glycol (meth)acrylate ethylester, FANCRYL FA-513A (dicyclopentanyl acrylate), FANCRYL FA-513M (dicyclopentanyl methacrylate), FANCRYL FA-711MM (pentamethylpiperidinyl methacrylate), and FANCRYL FA-712HM (tetramethylpiperidinyl methacrylate) made by Hitachi Chemical Co., Ltd., functional monomer SR&CD series made by Sartomer Japan Inc., and CN series commercially available as a functional oligomer.
[112] More specifically, commercial products described in "Kakyozai Handobukku" (Crosslinking Agent Handbook), edited by S. Yamashita (Taisei Publishing Co., Ltd., 1981); "UV-EB Koka Handobukku" (UV-EB Curing Handbook) (Starting Materials), edited by K. Kato (Kobunshi Kankoukai, 1985); "UV-EB Koka Gijutsu no Oyo to Shijyo" (Application and Market of UV-EB Curing Technology), p. 79, edited by Rad Tech Study (CMC Publishing Co., Ltd., 1989); and "Poriesuteru Jushi Handobukku' (Polyester Resin Handbook), written by E. Takiyama (The Nikkan Kogyo Shimbun Ltd., 1988) or radical-polymerizable (meth)aciylic ester monomers known in the art can be used. Photocurable polymerizable compounds used for photopolymerizable compositions and described in publications such as JP-H07-159983A (JP1995-159983A), JP-H07-031399 (JP1995-031399A), JP-H08-224982A (JP1996-224982A), JP-H10-000863A (JP 1998-000863A), JP-H09-134011A (JP1997-134011A), and JP514014B are known as the radical polymerizable compound. The (meth)acrylic esters described therein can be used for the ink composition according to the present invention.
[113] Among these, (meth)acrylic ester having an amino group or a substituted amino group is preferable. By having an amino group or a substituted amino group, it is possible to obtain an ink composition which is excellent in dispersibility of the aluminum metal pigment.
[114] An alkyl group having a carbon number of 1 to 5 can be preferably used as the

substituent of the substituted amino group. A substituted amionoalkyl (meth)acrylate having an alkyl group with a carbon number of 1 to 5 can be more preferably used as the additional monofunctional monomer and dimethyl aminoethyl (meth)acrylate can be yet more preferably used.
[115] Polyfunctional Monomer
[116] The ink composition according to the present invention includes a polyfunctional monomer as the radical polymerizable compound. The polyfunctional monomer occupies 0.1 to 20 mass% in the total mass of Component B.
[117] When the content of the polyfunctional monomer in Component B is greater than 20 mass%, the flexibility and stretchability of the cured film are deteriorated. In terms of curability, film hardness, and flexibility, the content of the polyfunctional monomer in Component B is in the range of 0.5 to 19.9 mass% and more preferably in the range of 2 to 18 mass%.
[118] The polyfunctional monomer is preferably a polyfunctional monomer having two or more radical-polymerizable ethylenically-unsaturated groups, more preferably a polyfunctional monomer having two or more ethylenically-unsaturated groups selected from the group consisting of a (meth)acrylate group, a (meth)acrylamide group, a vinyloxy group, and an N-vinyl group, and yet more preferably a polyfunctional monomer having at least two (meth)acrylate groups.
The number of functional groups in the polyfunctional monomer is preferably in the range of 2 to 6, more preferably in the range of 2 to 4, and yet more preferably 2.
[120] Examples of the polyfunctional monomer include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, bis(4-(meth)acryloxy polyethoxyphenyl) propane, neopentyl glycol di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, propoxylated neopentyl glycol di(meth)acrylate, hydroxy pivalic neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraehtylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, ethyleneoxide (EO)-modified pentaerythritol tri(meth)acrylate, propyleneoxide (PO)-modified pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, PO-modified pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate tolylene isocyanate urethane prepolymer, pentaerythritol tri(meth)acrylate

hexamethylene diisocyanate urethane prepolymer, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol tetra(meth)acrylate, EO-modified dipentaerythritol tetra(meth)aciylaie, PO-modifed dipentaerythritol tetra(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, EO-modified
tetramethylolmethane tetra(meth)acrylate, PO-modified tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, modified glycerin tri(meth)acrylate, modified bisphenol A di(meth)acrylate, PO-adduct di(meth)acrylate of bisphenol A, EO-adduct di(meth)acrylate of bisphenol A, dipentaerythritol hexa(meth)acrylate, caplactone-modified dipentaerythritol hexa(meth)acrylate, 2,2-bis(4-(meth)acryloxy polyethoxyphenyl) propane, diallyl phthalate, and triallyl trimellitate. [0121 ] A vinylether compound may be used as the radical polymerizable compound.
[122] Examples of the vinylether compound include di- or tri-vinyl ether compounds such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, and trimethylolpropane trivinyl ether, and monovinyl ether compounds such as ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, hydroxyethyl monovinyl ether, hydroxybutyl vinyl ether, hydroxynonyl monovinyl ether, 2-ethylhexyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl monovinyl ether.
[123] The content of Component B in the ink composition is preferably in the range of 65 to 95 mass% and more preferably in the range of 75 to 92 mass%, in terms of flexibility and metallic gloss.
[124] (Component C) Radical Photopolymerization Initiator
[125] The ink composition according to the present invention includes (Component C) a radical photopolymerization initiator (hereinafter, referred to as "polymerization initiator"). The polymerization initiator is a compound that absorbs external energy such as the active radiation to generate polymerization initiating species. Examples of the polymerization initiator used in the present invention include aromatic ketones, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole

compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene
compounds, active ester compounds, and compounds having a carbon-halogen bond.
Specific examples of the polymerization initiator include polymerization initiators described in
JP2008-10819QA and JP2009-096985A. These polymerization initiators may be used singly
or in a combination of two or more.
[126] Among these, acylphosphine compounds and aromatic ketones can be preferably used
as the polymerization initiator. Preferable examples of the aromatic ketones include
thioxanthone compounds. It is particularly preferable that acylphosphine compounds and
thioxanthone compounds are used together.
[127] Acylphosphine Compound
[128] Examples of the acylphosphine compound include acylphosphine oxide compounds
described in Paragraph 0080 to 0098 of JP2009-096985A. Among these compounds,
compounds having a structure expressed by Formula (c-1) or Formula (c-2) in their structures.
[129] Formulas (c-1) and (c-2)

Particularly, the acylphosphine oxide compound is preferably compounds having a
chemical structure expressed by Formula (c-3) or Formula (c-4).
[131] Formula (c-3)

[132] In Formula (c-3), R6, R7, and R8 represent aromatic hydrocarbon groups which may
have a methyl group or an ethyl group as a substituent.
[133] The monoacylphosphine oxide compound expressed by Formula (c-3) is preferably is a
compound in which R6, R7, and R8 is a phenyl group which may have a methyl group as a
substituent, and more preferably a compound in which R7 and R8 are a phenyl group and R6 is
a phenyl group having 1 to 3 methyl groups.
[134] Among these compounds, the monoacylphosphine oxide compound expressed by
Formula (c-3) is preferably 2,4,6-trimethylbenzoyl diphenylphosphine oxide (Darocur TPO
made by Ciba Specialty Chemicals Co., Ltd. and Lucirin TPO made by BASF Co., Ltd.).
[135] Formula (c-4)

18

[136] In Formula (c-4), R9, R10, and R11 represent an aromatic hydrocarbon group which may
have a methyl group or an ethyl group as a substituent.
[137] The bisacylphosphine oxide compound expressed by Formula (c-4) is preferably a
compound in which R9 to R11 is a phenyl group which may have a methyl group as a
substituent and more preferably a compound in which R11 is a phenyl group and R9 and R10 are
a phenyl group having 1 to 3 methyl groups.
[138] Among these compounds, the bisacylphosphine oxide compound expressed by Formula
(c-4) is preferably bis(2,4,6-trimethylbenzoyI) phenylphosphine oxide (IRGACURE 819 made
by Ciba Specialty Chemicals Co., Ltd.).
[139] Thioxanthone Compound
The thioxanthone compound is preferably a compound expressed by Formula (c-5).
[141] Formula (c-5)

[142] In Formula (c-5), R1 to R8 independently represent a hydrogen atom, an alkyl group, a
halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, an alkylthio
group, an alkylamino group (including one substitution and two substitutions), an alkoxy
group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxyl group, or a sulfo
group.
[143] The carbon number of the alkyl part in the alkyl group, the alkylthio group, the
alkylamino group, the alkoxy group, the alkoxycarbonyl group, the acyloxy group, and the
acyl group is preferably in the range of 1 to 20, more preferably in the range of 1 to 8, and yet
more preferably in the range of 1 to 4.
[144] Two adjacent groups of R1 to R8 may be linked to each other to form a ring. The
structure of the formed ring may be a five-membered or six-membered aliphatic or aromatic
ring or a heterocycle having an atom other than a carbon atom, or may be a binuclear ring such
as a condensed ring in which the formed rings are further combined with each other. This

ring structure may further have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, a cyano group, an amino group, an alkylthio group, an alkylamino group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxy group, and a sulfo group. Examples of a hetero atom when the formed ring structure is a heterocycle include N, O, and S.
[145] Examples of the thioxanthone compound include thioxanthone, 2-isopropyl thioxanthone, 2-chloro thioxanthone, 2-dodecyl thioxanthone, 2,4-diethyl thioxanthone, 2,4-dimethyl thioxanthone, 1-methoxycarbonyl thioxanthone, 2-ethoxycarbonyl thioxanthone, 3-(2-methoxyethoxycarbonyl) thioxanthone, 4-buthoxycarbonyl thioxanthone,
3- buthoxycarbonyl-7-methyl thioxanthone, l-cyano-3-chloro thioxanthone, l-ethoxycarbonyl-3-chloro thioxanthone, l-ethoxycarbonyl-3-ethoxy thioxanthone, l-ethoxycarbonyl-3-amino thioxanthone, l-ethoxycarbonyl-3-phenylsulfuryl thioxanthone, 3,4-di(2-(2-methoxyethoxy) ethoxycarbonyl) thioxanthone,
1- ethoxycarbonyl-3-(l-methyl-l-morpholinoethyl) thioxanthone,
2- methyl-6-dimethoxymethyl thioxanthone, 2-methyl-6-(l,l-dimethoxybenzyl) thioxanthone, 2-morpholinomethyl thioxanthone, 2-methyl-6-morpholinomethyl thioxanthone, n-allylthioxanthone-3,4- dicarboximide, n-octylthioxanthone-3,4-dicarbo ximide, N-(l,l,3,3-tetramethylbutyl) thioxanthone-3,4-dicarboximide, 1-phenoxy thioxanthone, 6-ethoxycarbonyl-2-methoxy thioxanthone, 6-ethoxycarbonyl-2-methyl thioxanthone, thioxanthone-2-polyethylene glycol ester, and 2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthone-2-yl oxy)-N,N,N-trimethyl-1 -propane aminium chloride.
[146] Among these, in terms of availability or curability, 2-isopropyl thioxanthone and
4- isopropyl thioxanthone are more preferable.
In the present invention, in terms of curability, it is preferable that the acylphosphine compound and the thioxanthone compound are used together.
[148] When the acylphosphine compound and the thioxanthone compound are used together, the mass ratio of acylphosphine compound: thioxanthone compound are used together is preferably in the range of 99:1 to 1:99, more preferably in the range of 90:10 to 50:50, and yet more preferably in the range of 80:20 to 50:50.
[149] In the present invention, in terms of curability, the total amount used of the radical photopolymerization initiator is preferably in the range of 1 to 20 mass% with respect to the total mass of the ink composition, more preferably in the range of 3 to 15 mass%, and yet

more preferably in the range of 5 to 10 mass%.
[150] (Component D) Colorant other than Component A
[151] The ink composition according to the present invention may include (Component D) a colorant other than Component A, in addition to the aluminum metal pigment of Component A. By using the aluminum metal pigment and the colorant other than Component A together, it is possible to enable a metallic-gloss image to have various color variations.
[152] The colorant is not particularly limited, but pigments and oil-soluble dyes which are excellent in weather resistance and color reproducibility can be preferably used and can be selected and used from known colorants such as soluble-dyes. In terms of prevention of the deterioration in sensitivity to a curing reaction due to the active radiation, it is preferable that compounds not serving as a polymerization inhibitor are selected.
[153] The pigment used in the present invention is not particularly limited. For example, organic or inorganic pigments described with the following numbers in the color index can be used. Examples of the pigment include red or magenta pigments such as Pigment Reds 3, 5, 19, 22, 31, 38, 42, 43, 48:1, 48:2, 48:3, 48:4, 48:5, 49:1, 53:1, 57:1, 57:2, 58:4, 63:1, 81, 81:1, 81:2, 81:3, 81:4, 88, 104, 108, 112, 122, 123, 144, 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, and 257, Pigment Violets 3, 19, 23, 29, 30, 37, 50, and 88, and Pigment Oranges 13, 16, 20, and 36, blue or cyan pigments such as Pigment Blues 1, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17-1, 22,27, 28, 29, 36, and 60, green pigments such as Pigment Greens 7, 26, 36, and 50, yellow pigments such as Pigment Yellows 1, 3, 12,13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 120, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, and 193, and black pigments such as Pigment Blacks 7, 28, and 26. These pigments can be used depending on the application.
[154] Titanium dioxide can be preferably used as a white pigment.
[155] Titanium dioxide is not particularly limited. Known titanium dioxides used as a white pigment can be properly selected and used. Rutile-type titanium dioxide and anatase type titanium dioxide can be both used, but the rutile-type titanium dioxide can be preferably used in terms of low catalytic activity and excellent temporal stability.
[156] Titanium dioxides are commercially available and examples thereof include Tipaque CR60-2 and Tipaque A-220 (both of which are made by Ishihara Sangyo Co., Ltd.) and KRONOS 1001,1014, 1071,1074, 1075, 1077, 1078, 1080, 1171, 2044, 2047, 2056, 2063, 2080, 2081, 2084, 2087, 2160, 2190, 2211, 2220, 2222,2225, 2230, 2233, 2257, 2300, 2310, 2450, 2500, 3000, and 3025 (all of which are made by KRONOS Co., Ltd.)

The titanium dioxide may be subjected to surface treatment if necessary. Specifically, the titanium dioxides are treated with silica, alumina, zinc, zirconia, organics, or the like and are different in weather resistance or lyophilic properties depending on the treatment methods. In the present invention, the titanium dioxides are preferably treated with alumina, zinc, zirconia, or basic organics.
[158] In the present invention, a disperse dye may be used within the range in which it is dissolved in a water-immiscible organic solvent. The disperse dye generally includes water-soluble dyes and can be preferably used within the range in which it is dissolved in the water-immiscible organic solvent.
[159] Specific examples of the disperse dye include C.I. Disperse Yellows 5, 42, 54, 64, 79, 82, 83, 93, 99, 100, 119, 122, 124, 126, 160, 184:1, 186, 198, 199, 201, 204, 224, and 237, C.I. Disperse Oranges 13, 29, 31:1, 33, 49, 54, 55, 66, 73, 118,119, and 163, C.I. Disperse Reds 54, 60, 72, 73, 86, 88, 91,92, 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167:1, 177, 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356, and 362, C.L Disperse Violet 33, C.I. Disperse Blues 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165:1, 165:2, 176, 183, 185, 197, 198, 201, 214, 224, 225, 257, 266, 267, 287, 354, 358, 365, and 368, and C.I. Disperse Greens 6:1 and 9.
[160] Various dispersion instruments such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet type jet mill, and a paint shaker can be used to disperse the colorant.
[161] The colorant may be directly added along with other components at the time of preparing the ink composition. For the purpose of improvement in dispersibility, the colorant may be added to and uniformly dispersed in a solvent or a dispersion medium such as the polymerizable compound used in the present invention in advance and then the resultant may be blended.
[162] In the present invention, in order to avoid the deterioration in solvent resistance when the solvent remains in the cured image and the problem with a volatile organic compound (VOC) in the remaining solvent, it is preferable that the colorant is added to blended with the dispersion medium such as the polymerizable compound in advance. In consideration of only the viewpoint of dispersibility, a monomer having the lowest viscosity is preferably selected as the polymerizable compound used for the addition of the colorant. One or two or more types of the colorants can be properly selected and used depending on the application of the ink composition.

[163] When the colorant such as a pigment existing in solid in the ink composition is used, the colorant, the dispersant, and the dispersion medium should be selected and the dispersing conditions and the filtering conditions should be set, so that the volume-average particle diameter of the colorant particles is preferably in the range of 0.005 to 0.5 Jim, more preferably in the range of 0.01 to 0.45 jam, and yet more preferably in the range of 0.015 to 0.4 |Jm. By this management of particle diameter, it is possible to suppress the clogging of head nozzles and to maintain the storage stability, transparency, and curing sensitivity of the ink composition, which is preferable.
[164] The content of the colorant in the ink composition can be properly selected depending on the color and the application, but is preferably in the range of 0.01 to 30 mass% with respect to the total mass of the ink composition.
[165] (Component E) Dispersant
[166] The ink composition according to the present invention preferably includes a dispersant. Particularly, when a pigment is used, it is preferable that the ink composition includes a dispersant in order to stably disperse the pigment in the ink composition. A polymer dispersant can be preferably used as the dispersant.
Examples of the polymer dispersant include DISPERBYK (registered trademark)-101, 102, 103, 106, 111, 161, 162, 163, 164, 166, 167, 168, 170, 171, 174, and 182 (made by BYK-Chemie); EFKA (registered trademark)-4010, 4046, 4080, 5010, 5207, 5244, 6745, 6750, 7414, 745, 7462, 7500, 7570, 7575, and 7580 (made by EFKA Additives Co., Ltd.); DISPERSE AID 6, 8, 15, 9100 (made by San Nopco Limited); various SOLSPERSE dispersants such as SOLSPERSE (registered trademark) 2000, 3000, 5000, 9000, 12000, 13240, 13940, 17000, 22000, 24000, 26000, 28000, 32000, 36000, 39000, 41000, and 71000 (made by Lubrizol Corporation); ADEKA (registered trademark) Pluronic L31, F38, L42, L44, L61, L64, F68, L72, P95, F77, P84, F87, P94, L101, P103, F108, L121, and P-123 (made by ADEKA Corporation); IONET S-20 (made by Sanyo Chemical Industries Ltd.); and DISPARLON (registered trademark) KS-860, 873 SN, and 874 (polymer dispersant), #2150 (aliphatic polyvalent carboxylate), #7004 (polyether ester type) (made by Kusumoto Chemicals Ltd.).
[168] The content of the dispersant in the ink composition can be properly selected depending on the application, but is preferably in the range fo 0.05 to 15 mass% with respect to the total mass of the ink composition.
[169] (Component F) Surfactant

£ J
[170] The ink composition used in the present invention may include a surfactant to give stable ejectability for a long time. Examples of the surfactant are described in JP-S62-173463A (JP1987-173463A) and JP-S62-183457 (JP1987-183457). For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalene sunfonates, and fatty acid salts, nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylallyl ethers, acetylene glycols, and polyoxyethylene polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts can be used.
[171] Other Components
[172] The ink composition according to the present invention may include sensitizers, polymerization inhibitors, ultraviolet absorbents, antioxidants, anti-fading agents, conductive salts, solvents, polymer compounds, and basic compounds described in JP2009-096985A as other components.
[173] Ink Properties
[174] In the present invention, the viscosity of the ink composition at 25°C is preferably equal to or less than 40 mPa-s in consideration of the ejectability, more preferably in the range of 5 to 40 mPa s, and yet more preferably in the range of 7 to 30 mPa s. The viscosity at the ejection temperature (which is preferably in the range of 25°C to 80°C and more preferably in the range of 25°C to 50°C) is preferably in the range of 3 to 15 mPa-s and more preferably in the range of 3 to 13 mPa-s. In the ink composition according to the present invention, it is preferable to properly adjust the composition ratio so that the viscosity is in the above-mentioned range. By setting the viscosity at the room temperature to be high, it is possible to avoid the infiltration of the ink composition into a recording medium and to reduce uncured monomers even when a porous recording medium is used. It is also possible to suppress the permeation of ink at the time of landing the droplets of the ink composition, thereby improving the image quality.
[175] The surface tension of the ink composition according to the present invention at 25°C is preferably in the range of 20 to 35 mN/ra and more preferably in the range of 23 to 33 mN/m. When an image is recorded on various recording media such as polyolefm, PET, a coated sheet, and a non-coated sheet, the surface tension is preferably equal to or greater than 20 mN/m in terms of permeation and infiltration and is preferably equal to or less than 35 mN/m in terms of wettability.
[176] II. Ink Set
The ink set according to the present invention includes the ink composition according

to the present invention and at least one ink composition including the colorant other than Component A.
[178] Known radical polymerizable ink compositions can be used as the ink composition including the colorant other than Component A. The ink composition is not particularly limited, but ink compositions including the same components as the ink composition according to the present invention other than Component A. The colorants of Component D can be preferably used as the colorant other than Component A.
[179] When the ink set including the ink composition according to the present invention is used, the ink set is not particularly limited as long as the ink set includes at least one ink composition according to the present invention and includes two or more types of ink compositions in which the ink composition according to the present invention and the ink composition other than the ink composition according to the present invention are combined. However, it is preferable that the ink set includes at least one ink composition of a color selected from the group consisting of cyan, magenta, yellow, black, white, light magenta, and light cyan.
[180] The ink set according to the present invention can be suitably used in the inkjet recording method according to the present invention.
[181] III. Inkjet Recording Method and Printed material
[182] The inkjet recording method according to the present invention includes an image forming process (hereinafter, also referred to as a process (a)) of ejecting the ink composition according to the present invention to form an image on a recording medium and a curing process (hereinafter, also referred to as a process (b)) of irradiating the ejected ink composition with active radiation to cure the ink composition and to acquire a printed material having a cured image on the recording medium.
[183] The printed material according to the present invention is obtained by the use of the inkjet recording method according to the present invention.
[184] First, the process (a) will be described.
[185] In the present invention, a recording medium is not particularly limited and can employ known recording media. Examples thereof include a sheet of paper, a sheet obtained by laminating plastics (such as polyethylene, polypropylene, and polystyrene), a metal plate (such as aluminum, zinc, and copper), a plastic film (such as polyvinyl chloride, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene,

polycarbonate, and polyvinyl acetal), and a sheet of paper or a plastic film on which the metal is laminated or deposited. A non-absorbable recording medium can be suitably used as the recording medium in the present invention.
[186] The inkjet recording apparatus used in the inkjet recording method according to the present invention is not particularly limited and known inkjet recording apparatuses which can achieve a desired resolution can be arbitrarily selected and used. It is possible to eject the ink composition to a recording medium in the process (a) of the inkjet recording method according to the present invention by the use of any known inkjet recording apparatus including commercially-available products.
Examples of the inkjet recording apparatus which can be used in the present invention include an apparatus having an ink supply system, a temperature sensor, and an active radiation source.
[188] The ink supply system includes, for example, a source tank containing the ink composition according to the present invention, a supply pipe, an ink composition supply tank disposed just before an inkjet head, a filter, and a piezoelectric inkjet head. The piezoelectric inkjet head can be driven to eject multi-sized dots preferably in the range of 1 to 100 pL, more preferably in the range of 3 to 42 PL, and yet more preferably in the range of 8 to 30 pL with a resolution preferably in the range of 320x320 to 4,000x4,000 dpi, more preferably in the range of 400x400 to 1,600x1,600 dpi, and yet more preferably in the range of 720x720 dpi. The "dpi" in the present invention means the number of dots per 2.54 cm.
[189] In order to obtain an image having excellent metallic gloss, it is preferable that the aluminum metal pigment with a large size is blended into the ink composition. On the other hand, when the aluminum metal pigment with a large size is blended into the ink composition, the nozzles of the inkjet head may be clogged. Accordingly, the diameter of the nozzle apertures ejecting the ink composition according to the present invention in an image forming process is preferably 20 μm, more preferably in the range of 21 to 100 μm, and yet more preferably in the range of 22 to 50 μm. When the diameter of the nozzle apertures is in the above-mentioned numerical range, the nozzles of the inkjet head are not clogged and an image having excellent metallic gloss.
[190] Examples of the shape of the nozzle apertures include a circle, an ellipse, and a polygonal. When the shape of the nozzle apertures is not circular, the diameter of the apertures means the diameter of a circle corresponding to the area of the aperture.
[191] In the present invention, since the temperature of the ink composition to be ejected

should be preferably constant, the region from the ink composition supply tank to the inkjet head can be insulated and heated. The method of controlling the temperature is not particularly limited, but it is preferable that plural temperature sensors are disposed around the pipes to perform a heat control corresponding to the flow rate of the ink composition and the ambient temperature. The temperature sensors may be disposed around the ink composition supply tank and the nozzles of the inkjet head. It is preferable that the body of the head unit to be heated is thermally blocked or insulated from the external air so as not to be influenced by the ambient temperature. In order to shorten the startup time of a printer required for the heating, or to reduce the loss of thermal energy, it is preferable that the head unit should be insulated from the other parts and the thermal capacity of the total heating unit should be small.
[192] Since a radiation-curing ink composition like the ink composition according to the present invention has a higher viscosity than that of an aqueous ink composition typically used as an inkjet-recording ink composition, the variation in viscosity thereof due to the variation in temperature at the time of ejection is also great. The variation in viscosity of the ink composition has a great influence on the variation in size of the droplets and the variation in droplet ejecting speed, and causes the deterioration in image quality. Accordingly, it is necessary to keep the temperature of the ink composition at the time of ejection constant. Therefore, in the present invention, the control width of the temperature of the ink composition is preferably ±5°C of the set temperature, more preferably ±2°C of the set temperature, and yet more preferably ±1°C of the set temperature.
[193] The process (b) will be described below.
[194] The ink composition ejected onto a recording medium is cured by the irradiation with the active radiation. This is because the polymerization initiator included in the ink composition according to the present invention is decomposed by the irradiation with the active radiation to generate polymerization initiating species such as radicals and the polymerization reaction of the polymerizable compound is initiated and promoted by the initiating species. At this time, when a sensitizer coexists with the polymerization initiator in the ink composition, the sensitizer in the system absorbs the active radiation and is excited and promotes the decomposition of the polymerization initiator by coming in contact with the polymerization initiator, thereby achieving a curing reaction with a higher sensitivity.
[195] Here, α-rays, γ-rays, X-rays, ultraviolet rays, visible rays, or electron rays may be used as the active radiation. The peak wavelength of the active radiation depends on the

absorption characteristic of the sensitizer, but is preferably in the rage of 200 to 600 nm, more preferably in the range of 300 to 450 nm, and yet more preferably in the range of 350 to 420 nm.
[196] The photopolymerization initiator in the ink composition according to the present invention has sufficient sensitivity even to the low-power active radiation. Therefore, the curing is performed with the exposing surface lighting intensity preferably in the range of 1,000 to 3,000 mW/cm2 and more preferably in the range of 1,200 to 2,500 mW/cm2.
A mercury lamp or a gas or solid laser is used as the active radiation source. A mercury lamp and a metal halide lamp are widely known as the light source used to cure the UV-curable inkjet recording ink composition. However, from the viewpoint of environmental protection, it is strongly required that mercury should be free. Accordingly, the replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. An LED (UV-LED) and an LD (UV-LD) have a small size, a long lifetime, a high efficiency, and a low cost and are expected to be a photo-curable inkjet light source.
[198] The light-emitting diode (LED) and the laser diode (LD) can be used as the active radiation source. Particularly, when a UV light source is required, the UV-LED and the UV-LD can be used. For example, a violet LED of which the main emission spectrum has a wavelength between 365 nm and 420 nm is brought to the market by Nichia Corporation. When shorter wavelengths are required, the LED which can emit active radiation centered on between 300 nm and 370 nm and which is disclosed in U.S.P. No. 6,084,250 can be used as the LED. Other UV-LEDs are available and can emit radiation of different ultraviolet bands. The preferable active radiation source in the present invention is the UV-LED and the more preferable active radiation source is a UV-LED having a peak wavelength between 350 to 420 nm.
[199] The ink composition according to the present invention is irradiated with such active radiation preferably for 0.01 to 120 seconds, more preferably for 0.01 to 90 seconds, and yet more preferably for 0.01 to 10 seconds.
[200] In the inkjet recording method according to the present invention, it is preferable that the active radiation is applied with an exposing surface lighting intensity less than 2,000 mW/cm2 for 0.01 to 10 seconds after ejecting the ink composition to cure the ink composition.
[201] The application condition and the basic application method of the active radiation are disclosed in JP-S60-132767A (JP1985-132767A). Specifically, light sources are disposed on

both sides of the head unit including the ink composition ejecting device and the head unit and the light source are scanned in a so-called shuttle manner. The application of the active radiation is performed in a predetermined time (preferably 0.01 to 0.5 seconds, more preferable 0.01 to 0.3 seconds, and yet more preferably 0.01 to 0.15 seconds) after the landing of the ink composition. In this way, by controlling the time from the landing of the ink composition to the application into a very short time, it is possible to prevent the ink composition landed on the recording medium from being infiltrated into the recording medium before it is cured. Since the exposing can be carried out before the ink composition permeates a porous recording medium up to a deep part which the light does not reach, the remaining of non-reacted monomers can be suppressed, which is preferable.
[202] The curing may be finished by the use of another light source not requiring the driving. PCT International Publication No. 99/54415 discloses a method using optical fibers or an application method of bringing a collimated light source into contact with a specular surface disposed on the head unit side to apply UV light to a recording unit. These curing methods can be used in the inkjet recording method according to the present invention.
[203] By employing the above-mentioned inkjet recording method, the dot size of the landed ink composition can be kept constant for various recording media having different surface wettable properties, thereby improving the image quality. In order to obtain a color image, it is preferable that the color ink compositions are sequentially superimposed from the color having the lowest lightness value. By sequentially superimposing the ink compositions from the color having the lowest lightness value, the active radiation can easily reach the deep ink composition, thereby expecting the excellent curing sensitivity, the decrease of remaining monomers, and the improvement in adhesion. The ink compositions of all colors can be ejected and exposed in a bundle, but it is preferable in terms of the promotion of curing that the ink compositions are exposed color by color.
[204] In the inkjet recording method according to the present invention, the ink set including one or more ink compositions according to the present invention can be suitably used. The order of the colored ink compositions to be ejected is not particularly limited, but it is preferable that the colored ink compositions are applied to a recording medium from the color having the lowest lightness value. When the ink composition according to the present invention and the ink compositions of yellow, cyan, magenta, and black are used, the ink compositions are preferably applied to the recording medium in the order of the ink composition according to the present invention → yellow → cyan → magenta → black

When white is additionally used, the ink compositions are preferably applied to the recording medium in the order of white → the ink composition according to the present invention → yellow → cyan → magenta black. The present invention is not limited to this example, and an ink set including at least the ink compositions of light cyan, and light magenta and the ink composition of deep colors of cyan, magenta, black, white, and yellow may be used. In this case, it is preferable that the ink compositions are applied to the recording medium in the order of white → the ink composition according to the present invention → light cyan → light magenta → yellow → cyan → magenta → black.
[205] IV. Mold Printed material Manufacturing Method and Mold Printed Material
[206] The mold printed material manufacturing method according to the present invention includes an image forming process (hereinafter, also referred to as a process (a)) of ejecting the ink composition according to the present invention to form an image on a recording medium, a curing process (hereinafter, also referred to as a process (b)) of irradiating the ejected ink composition with active radiation to cure the ink composition and to acquire a printed material having a cured image on the recording medium, and a process (hereinafter, also referred to as a process (c)) of molding the printed material.
The mold printed material according to the present invention is obtained by the use of the mold printed material manufacturing method.
[208] The process (a) and the process (b) in the mold printed material manufacturing method according to the present invention are the same as the process (a) and the process (b) in the inkjet recording method according to the present invention and the recording medium suitably used in the mold printed material manufacturing method according to the present invention will be described below.
[209] The recording medium used in the mold printed material manufacturing method according to the present invention is not particularly limited and known recording media suitable for the molding can be used. Specific examples thereof include polyolefin resins such as polyethylene, polypropylene, polymethylpentene, polybutene, and olefin-based thermoplastic elastomer, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, terephthalate-isophtalate-ethyleneglycol copolymer, terephthalate-ethyleneglycol-l,4-cyclohexane diethanol copolymer, and polyester-based thermoplastic elastomer, polyamide resins such as nylon 6, nylon 9, and nylon 6,6, fluorine-based resins such as polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene trifluoride, ethylene-ethylene tetrafluoride copolymer, and polyethylene tetrafluoride,

L >
acryl-based resins, polyvinyl chloride resins, polystyrene resins, and polycarbonate resins.
[210] As the acryl-based resins, resins such as polymethyl (meth)acrylaie, polyethyl (meth)acrylate, polybutyl (meth)acrylate, methyl (meth)acrylate-butyl (meth)acrylate copolymer, ethyl (meth)acrylate-butyl (meth)acrylate copolymer, and methyl (meth)acrylate-styrene copolymer can be singly or in a combination of two or more thereof.
[211] Among these, in terms of easy decorative printing or excellent resistance characteristics of the complete molded matter, a sheet of the polyethylene terephthalate resin, the polycarbonate resin, or a resin obtained by blending other resins with the polycarbonate resin can be preferably used. The recording medium may be a laminated body obtained by laminating one or two or more resin sheets.
[212] In the present invention, the thickness (the total thickness of the laminated body) of the recording medium is not particularly limited, as long as it is a resin sheet with a thickness in the range which allows the embossing, the vacuum molding, the pressure molding, and the vacuum and pressure molding employing both principles of the pressure molding and the vacuum molding. However, the thickness is preferably in the range of 50 to 2,000 μm, more preferably in the range of 100 to 1,500 μm, and yet more preferably in the range of 150 to 1,000 μm.
[213] If necessary, additives may be added to the thermoplastic resin sheet. Various additives can be added thereto by an appropriate amount within the range which does not cause any problem in the thermal behavior such as the surface gloss and the melting point. Examples thereof include ultraviolet absorbents such as benzotriazoles and benzophenones, optical stabilizers such as hindered amine-based radical assistants, lubricant such as silicone resin and wax, colorants, plasticizers, thermal stabilizers, antibacterial agents, antifungal agents, and antistatic agents.
[214] The mold printed material according to the present invention is manufactured by performing a molding process such as vacuum molding on a thermoplastic resin sheet, and an image is formed on the recording sheet by the use of the inkjet recording method before the molding.
[215] The image is generally formed on the rear surface (a side coming in contact with a mold in the vacuum molding) of a transparent sheet but may be formed on the opposite surface. In some cases, the image may be formed on only the opposite surface. In this case, the thermoplastic resin sheet serving as a substrate need not be transparent.
[216] In the present invention, the embossing, the vacuum molding, the pressure molding, or

I f
the vacuum and pressure molding can be used as the molding. Known instruments can be used as the instrument molding the printed material and may be incorporated with or separated from the inkjet recording apparatus.
[0217] The embossing is a process of giving a stereoscopic sense by indenting a printed material in an arbitrary shape such as patterns or letters and is performed, for example, using a roller or a press. An example of the embossing is a hot-cold pressing method and is referred to JP-H10-199360A (JP1998-199360A). An example of an embossing molding instrument using the hot-cold pressing method will be described below. In the embossing molding instrument, a lower surface plate (bottom surface plate) and an upper surface plate (top surface plate) are disposed to get close to and apart from each other. A plate-type heater is fixed to the lower surface plate and a plate-type heat is also fixed to the upper surface plate. Accordingly, the hot pressing can be carried out while heating a recording medium. In this hot press, a mold having protrusions corresponding to predetermined embossing shapes is mounted on the plate-type heater on the lower surface plate and a mold having recesses corresponding to the protrusions is mounted to come in contact with the heater fixed to the bottom surface of the upper surface plate. A recording medium having an image formed thereon is placed, a cushion sheet is disposed between the recording medium and the mold having the recesses, and the recording medium and the cushion sheet between the upper surface plate and the lower surface plate are pressed by lowering the upper surface plate or the like. The pressure in the hot pressing process is, for example, 30 tons and the heating temperature by the plate-type heater is, for example, 170°C. The upper surface plate is pressed against the lower surface plate and the recording medium and the cushion sheet are pinched between the molds, and this hot pressing state is maintained for about 3 minutes. The recording medium is heated by the heater with the molds interposed therebetween and plural protrusions are formed thereon by the thermal deformation. Subsequently, with the recording medium and the cushion sheet interposed between the molds, this is disposed between internal water-cooling surface plates not having a heater and is pressed by the use of the internal water-cooling surface plates under the conditions of a pressure of 30 tons and a time of about 3 minutes to perform a cold pressing process. Accordingly, the protrusion shapes thermally deformed by the hot pressing are held on the recording medium, thereby obtaining the mold printed material having been subjected to the embossing. The pressure and the heating temperature can be appropriately adjusted depending on the material of the printed material or the conditions of the processed shapes.

* :
The vacuum molding is a molding process of preliminarily heating a recording medium having an image formed thereon to a thermally-deformable temperature, suctioning the resultant to a mold by the depressurization and stretching, and stretching and cool-pressing the resultant against the mold. The pressure molding is a molding process of preliminarily heating a recording medium having an image formed thereon to a thermally-deformable temperature, pressing the resultant from the opposite side of a mold, and cool-pressing the resultant against the mold. The pressure and vacuum molding is a molding process of simultaneously performing the depressurizing and the pressurizing. Specifically, the article, "Thermal Molding", described in p. 766 to p. 768 of Encyclopedia of Polymer (published by Maruzen Co., Ltd.) and documents cited in the article can be referred to.
[219] Examples
[220] Examples and comparative examples will be described to explain the present invention more specifically. However, the present invention is not limited to the examples. In the following description, "part" means "part by mass" as long as it is described differently, and "%" means "mass%".
[221] Preparation of Metal Pigment Mill Base
[222] 50 part by mass (solid content) of aluminum metal pigment (ROTOVARIO 500 022, aluminum-flake pigment paste, made by Eckart Co.)
[223] 40 part by mass of 2-(2-ethoxymethoxy)ethyl acrylate
[224] 10 part by mass of Solsperse 36000 (made by Lubrizol Corporation)
[225] These components were dispersed for 20 hours by the use of a ball mill and zirconia beads with a diameter of 0.2 mm to obtain a metal pigment mill base.
[226] The volume-average particle diameter of the aluminum metal pigment was measured by the use of a laser diffraction/scattering particle size distribution analyzer (product name: Microtrac MT3300EX, made by Nikkiso Co., Ltd.) and the result of 0.25 fjm was obtained.
[227] Similarly to the preparation of the metal pigment mill base, a cyan mill base, a magenta mill base, a yellow mill base, a black mill base, and a white mill base were prepared under the compositions and conditions shown in Table 1.

Table 1
[229] Pigments
[230] Cyan pigment: IRGALITE BLUE GLVO (made by Ciba Specialty Chemicals Co., Ltd.)
[231] Magenta pigment: CINQUASIA MAGENTA RT-355D (made by Ciba Specialty Chemicals Co., Ltd.)
[232] Yellow pigment: NOVOPERM YELLOW H2G (Clariant International Ltd.)
[233] Black pigment: SPECIAL BLACK 250 (made by Ciba Specialty Chemicals Co., Ltd.)
[234] White pigment: alumina-processed titanium dioxide
[235] Monofunctional Monomer
[236] EOEOEA (2-(2-ethoxymethoxy)ethyl acrylate)
[237] Dispersant

SOLSPERSE 2000 (made by Lubrizol Corporation)
[239] SOLSPERSE 32000 (made by Lubrizol Corporation)
[240] SOLSPERSE 5000 (made by Lubrizol Corporation)
[241] SOLSPERSE 36000 (made by Lubrizol Corporation)
[242] Examples 1 to 16 and Comparative Example 1 and 2
[243] Method of Producing Ink Composition
[244] The materials described in Table 2 were agitated to obtain ink compositions according to Examples 1 to 16 and Comparative Examples 1 and 2. The numerical values in the table represent the amounts of components blended (part by mass).
[245] Inkjet Image Recording
[246] An image was recorded on a recording medium by the use of an inkjet recording apparatus having piezoelectric inkjet nozzles. An ink supply system includes a source tank, a supply pipe, an ink supply tank disposed just before an inkjet head, a filter, and a piezoelectric inkjet head (with a diameter of nozzle apertures of 25 μm) and the region from the ink supply tank to the inkjet head was thermally blocked and heated. Temperature sensors were disposed around the ink supply tank and the nozzles of the inkjet head and the temperature was controlled so that the nozzles were always maintained at 40°C±2°C. The piezoelectric inkjet head was driven to eject multi-sized dots of 1 to 10 pL with a resolution in the range of 4,800x4,800 dpi. After the landing on the recording medium, UV light was condensed with an exposing surface lighting intensity of 700 mW/cm and the exposing system, the main scanning speed, and the ejection frequency were adjusted so that the UV light was applied in 0.1 seconds after the ink composition landed on the recording medium. The exposure energy was applied with an exposing time set to be variable. A high-cure mercury lamp HAN250NL (made by GS Yuasa Corporation) was used as a UV lamp. The term, "dpi", in the present invention means the number of dots per 2.54 cm. An ester film E5000 (with a thickness of 125 |Jm, made by Toyobo Co., Ltd.) was used as the recording medium.
[247] Evaluation of Ink
Evaluation of Curability
[249] A solid image with an average thickness of 12 μm was formed by the use of the inkjet recording method and the exposure energy (mJ/cm2) at which the sense of adhesion disappears was defined as a curing sensitivity. As the numerical value decreases, it means that the curing sensitivity increases.
[250] The curing sensitivity was evaluated using the following criteria.

t 1 *
[251] 5: Less than 3,500 mJ/cm2
[252] 4: Equal to or greater than 3,500 mJ/cm2 and less than 4,000 mJ/cm2
[253] 3: Equal to or greater than 4,000 mJ/cm2 and less than 4,500 mJ/cm2
[254] 2: Equal to or greater than 4,500 mJ/cm2 and less than 5,000 mJ/cm2 [025 5] 1: Equal to or greater than 5,000 mJ/cm2
[256] Within criteria 3 to 5, no practical problem was caused.
[257] Evaluation of Flexibility: Evaluation of Bendability of Cured Film
[258] A solid image with an average thickness of 4 μm was formed on a transparent substrate (ester film E5000) using the ink compositions and the inkjet recording method with an exposure dose of the lowest energy not giving the adhesion and the image was left under the conditions of a temperature of 23°G and a relative humidity of 60% for 1 day. Then, the central portion of the image was bent by 180° with hands and cracks of the cured film were observed. The observation results were evaluated as follows.
5: Cracks were generated in the cured film by 20 times.
[260] 4: Cracks were generated in the cured film by equal to or greater than 15 times and less than 20 times.
[261] 3: Cracks were generated in the cured film by equal to or greater than 10 times and less than 15 times.
[262] 2: Cracks were generated in the cured film by equal to or greater than 5 times and less than 10 times.
[263] 1: Cracks were generated in the cured film by less than 5 times.
[264] In the criteria of 3 to 5, no practical problem is caused.
[265] Evaluation of Film Hardness
[266] A solid image with an average thickness of 12 |im was formed on a transparent substrate (polycarbonate) using the ink compositions and the inkjet recording method with an excessive exposure dose (30,000 mJ/cm2) and the image was subjected to a pencil hardness test at 25°C in accordance with the JIS K5600-5-4.
[267] 8: Equal to or greater than 4H
[268] 7: 3H
6: 2H
[270] 5: H
[271] 4: F
[272] 3: HB

t
L «•
[273] 2: B
[274] 1: 2B
[275] In the criteria of 4 to 8, no practical problem is caused.
[276] Evaluation of Metallic Gloss
[277] A solid image with an average thickness of 12 jam was formed on a transparent substrate (polycarbonate) using the ink compositions and the inkjet recording method with an excessive exposure dose (15,000 mJ/cm2) and the image was evaluated with eyes as follows.
[278] 5: It can be determined as a metallic tone as observed from just above a horizontal image in the vertical direction.
4: It can be determined as a metallic tone at an oblique point of 30 degrees from the horizontal as observed from just above an image in the vertical direction.
[280] 3: It can be determined as a metallic tone at an oblique point of 60 degrees from the horizontal as observed from just above an image in the vertical direction.
[281] 2: It can be determined as a metallic tone at an oblique point of 90 degrees from the horizontal as observed from just above an image in the vertical direction.
[282] 1: Almost gray
[283] In the criteria of 3 to 5, no practical problem is caused.
[284] Table 2



[285] The abbreviations in Table 2 are as follows.
[286] Monofunctional Monomer
[287] PEA: 2-phenoxyethyl acrylate (the below compound, SR339 made by Sartomer Japan
Inc.)
[288] Viscoat#150: The below compound (made by Osaka Organic Chemical Industry Ltd.)
CTFA: Cyclic trimethylolpropane formal acrylate (the below compound)
[290] NVC: N-vinylcaprolactam (V-CAP, made by ISP Japan Ltd.) (polyfunctional
monomer)
[291] NPGPODA: propoxylated neopentyl glycol diacrylate (the below compound)
[292] Formulas

(N,N-dimethylaminoethyl acrylate)
[293] Polymerization Initiator
[294] Irg 819: bis(2,4,6-trimethylbenzoyl)phenyl phosphine oxide (IRGACURE 819, made
by Ciba Specialty Chemicals Co., Ltd.)
[295] ITX: mixture of 2-isopropyl thioxanthone and 4-isopropyl thioxanthone (FRISTCURE
ITX, made by ALBEMARLE Corporation)
[296] Examples 17 to 32
[297] By mixing and agitating materials described in Table 3, the ink compositions of yellow,
magenta, cyan, black, and white described in Experimental Examples 1 to 5 were obtained.
[298] One ink composition including the metal pigment described in Examples 1 to 16 and
the ink compositions of Experimental Examples 1 to 5 were combined to produce the ink sets
according to Examples 17 to 32.
In the inkjet image recording, images were formed under the same conditions, except
that the ink compositions according to Examples 1 to 16 were ejected by the use of a
piezoelectric inkjet head (with an aperture diameter of nozzles of 25 |im) and the ink

compositions according to Experimental Examples 1 to 5 were ejected by the use of a
piezoelectric inkjet head (with an aperture diameter of nozzles of 20 μm).
[300] When ink sets of plural colors including the ink compositions according to Examples 1
to 16 were used, it was possible to obtain images excellent in curability, flexibility, film
hardness, and metallic gloss.
[301] Table 3

[302] Example 33
[303] A vacuum molding was performed by the use of a vacuum molding machine
FORMING 300X (made by Seikosangyo Co., Ltd.). A printed material was prepared under
the same conditions as Example 1, except that a sheet of Panlight PC-1151 (made by Teijin
Chemicals Ltd.) was used as a recording medium in the inkjet recording method.
[304] The temperature of a heater was set so that the temperature of a support was at 90°C
and the wood mold shown in Fig. 1 was disposed at the center of a vacuum table, whereby the
vacuum molding was performed. It was observed with eyes whether cracks or white missing
were generated in the mold printed material. It was observed with eyes whether scratches are
present on the surface after the vacuum molding process. As a result, no crack or white
missing was observed.

WHAT IS CLAIMED IS:
1. An ink composition comprising:
(Component A) an aluminum metal pigment;
(Component B) a radical polymerizable compound; and
(Component C) a radical photopolymerization initiator,
wherein Component B includes 80 to 99.9 mass% of a monofunctional monomer and
0.1 to 20 mass% of a polyfunctional monomer in the radical polymerizable compound.
2. The ink composition according to claim 1, wherein the content of Component A in the ink
composition is in the range of 0.5 to 20 mass%.
3. The ink composition according to claim 1 or 2, wherein a compound expressed by Formula
(b-1) and/or a compound expressed by Formula (b-2) is contained as the monofunctional
monomer:
Formula (b-1)

(In Formula (b-1), R1 represents a hydrogen atom or a methyl group, X represents a single
bond, an alkylene group, an oxyalkylene group or a group having a combination of two or
more oxyalkylene groups, an ester bond, or a group having a combination of two or more
thereof, R2 and R3 independently represent a hydrogen atom or an alkyl group, R4 to R8
independently represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or
an aminoalkyl group, at least one of R4 toR8 is a hydrogen atom, and two or more of R2 to R8
are bonded to form a cyclic structure.)
Formula (b-2)

(In Formula (b-2), n represents an integer in the range of 1 to 5.).

4. The ink composition according to claim 3, wherein the total content of the compound expressed by Formula (b-1) and the compound expressed by Formula (b-2) in Component B is in the range of 5 to 99.9 mass% of the ink composition.
5. An ink set comprising at least one of the ink composition according to any one of claims 1 to 4 and an ink composition containing a colorant other than Component A.
6. An inkjet recording method comprising:
an image forming step of forming an image on a recording medium by ejecting the ink composition according to any one of claims 1 to 4; and
a curing step of curing the ink composition by irradiating the ejected ink composition with active radiation and acquiring a printed material having an image cured on the recording medium.
7. A printed material acquired using the inkjet recording method according to claim 6.
8. A method for manufacturing mold printed material comprising:
an image forming step of forming an image on a recording medium by ejecting the ink composition according to any one of claims 1 to 4;
a curing step of curing the ink composition by irradiating the ejected ink composition with active radiation and acquiring a printed material having an image cured on the recording medium; and
a step of molding the printed material.
9. A mold printed meterial acquired using the method for manufacturing mold printed material according to claim 8.