JP7332281B2 - Active energy ray-curable inkjet ink set and method for producing printed matter using active energy ray-curable inkjet ink set - Google Patents

Description

TECHNICAL FIELD The present invention relates to an active energy ray-curable inkjet ink set that is excellent in weather resistance and image sharpness.

Printing by an inkjet printer recording device is a method of ejecting ink from a nozzle and making it adhere to a recording material, and since the nozzle and the recording material are in a non-contact state, it has an irregular shape with curved surfaces and unevenness. Good printing can be done on the surface. Therefore, this printing method is expected to be used in a wide range of industrial applications.

On the other hand, in the field of interior and exterior building materials, the demand for high functionality such as high design, high durability, and low staining has been increasing in recent years, and inkjet technology, which can be used to create a variety of patterns, is attracting attention. there is In particular, building boards that are used outdoors for long periods of time require excellent resistance to heat, light, water, etc. (hereinafter simply referred to as weather resistance). are also required to have excellent weather resistance. In response to such demands, active energy ray-curable inkjet inks suitable for outdoor use have been developed (Patent Documents 1 and 2).

JP 2011-047152 A JP 2014-129481 A

Printed materials for outdoor use require strong weather resistance against sunlight. Until now, weather resistance was dependent on the characteristics of pigments, so strong pigments were limited to specific colors, and as full-color printed materials, the color balance was poor. Discoloration due to collapse of the coating was remarkable, and sufficient image sharpness and weather resistance could not be obtained. In addition, printed matter printed with color ink on a tarpaulin base material is widely used as banners and hanging banners installed outdoors. It was also observed that the function of

SUMMARY OF THE INVENTION An object of the present invention is to provide an active energy ray-curable inkjet ink set that can provide printed matter for outdoor installation with excellent image sharpness and weather resistance.

The objects of the invention have been achieved by:
1. An active energy ray-curable inkjet ink set having at least yellow ink, magenta ink, and cyan ink, each ink containing at least a pigment and a polymerizable compound, and the cyan ink having 1.3 to 2.8 % by weight of cyan pigment, the magenta ink contains 2.7-4.5% by weight of magenta pigment, and the yellow ink contains 2.0-5.0% by weight of yellow pigment. and an active energy ray-curable inkjet ink set, wherein the amount of each pigment is cyan pigment:magenta pigment:yellow pigment=1:1.3-2.0:1.5-2.4 (mass ratio).
2. 2. The active energy ray-curable inkjet ink set according to 1 above, wherein the yellow pigment is a nickel complex compound having an azo skeleton or a yellow pigment having a quinoxaline skeleton, and the magenta pigment is a magenta pigment having a quinacridone skeleton.
3. The yellow pigment is C.I. I. Pigment Yellow 150, 213, said magenta pigment being C.I. I. Pigment Red 122, 202, C.I. I. 3. The active energy ray-curable inkjet ink set according to 1 or 2 above, which is selected from Pigment Violet 19.
4. A method for producing a printed matter using the active energy ray-curable inkjet ink set described in 1 to 4 above.

According to the present invention, it is possible to obtain a printed matter for outdoor installation which has excellent image sharpness and excellent weather resistance.

<Active energy ray-curable inkjet ink set (hereinafter also abbreviated as ink set)>
The active energy ray-curable inkjet ink set of the present invention is an active energy ray-curable inkjet ink set having at least yellow ink, magenta ink and cyan ink, each ink containing at least a pigment and a polymerizable compound. , the amount of the cyan pigment contained in the cyan ink, the amount of the magenta pigment contained in the magenta ink, and the amount of the yellow pigment contained in the yellow ink is 1:1.3-2.0:1.5-2. 4 (mass ratio).

≪Pigments≫
Inorganic pigments or organic pigments can be used as the pigments used in the present invention.
As the inorganic pigment, titanium oxide, iron oxide, or carbon black produced by known methods such as contact method, furnace method and thermal method can be used.

Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinoflurone pigments, etc.), nitro pigments, nitroso pigments, aniline black and the like can be used.

Pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 180, 185, 213 and the like.

A nickel complex compound having an azo skeleton or a pigment having a quinoxaline skeleton is particularly preferred. I. Pigments selected from Pigment Yellow 150, 213 are preferred.
The content of the yellow pigment contained in the yellow ink of the invention is preferably 3.7 to 5.0% by mass.

Pigments used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57:1, 112, 122, 123, 168, 184, 202, 209, C.I. I. Pigment Violet 19 and the like.

A magenta pigment having a quinacridone skeleton is particularly preferred, and C.I. I. Pigment Red 122, 202, C.I. I. Pigments selected from Pigment Violet 19 are preferred.
The content of the magenta pigment contained in the magenta ink of the invention is preferably 3.5 to 4.5% by mass.

Pigments used in cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15:3, 15:4, 60, 16, 22. Especially C.I. I. Pigment Blue 15:3, 15:4 are preferred.
The content of the cyan pigment contained in the cyan ink of the present invention is preferably 1.3 to 2.8% by mass.

Other inks that can be used include black and white inks.
The pigment used in the black ink is at least one black pigment whose color index number is classified as Pigment Black. I. Pigment Black 7, 11, 34, 35, etc., but C.I. I. Pigment Black 7, and C.I. I. Pigment Black 35 is preferred.
The black pigment is preferably contained in the black ink in an amount of 1.6 to 3.0% by mass, preferably 1.1 to 2.1 (mass ratio) relative to 1 part of the cyan pigment.

Pigments used in white ink include C.I. I. Pigment White 6, 18, 21, etc. can be used depending on the purpose, but titanium oxide with high hiding power is preferable. , 603, 805, 806, 701, 800, 808” “Titanics JA-1, C, 3, 4, 5”, Ishihara Sangyo Co., Ltd. “Tipaque CR-50, 50-2, 57, 80, 90, 93 , 95, 953, 97, 60, 60-2, 63, 67, 58, 58-2, 85" "Tipaque R-820, 830, 930, 550, 630, 680, 670, 580, 780, 780-2 , 850, 855" "Tipake A-100, 220" "Tipake W10" "Tipake PF-740, 744" "TTO-55 (A), 55 (B), 55 (C), 55 (D), 55 (S), 55 (N), 51 (A), 51 (C)" "TTO-S-1, 2" "TTO-M-1, 2", DuPont "Tai Pure R-900, 902, 960, 706, 931" and the like.

The white pigment is preferably contained in an amount of 5 to 15% by mass with respect to the white ink, and is preferably contained in an amount of 1.4 to 4.5 (mass ratio) with respect to 1 part of the cyan pigment.

As for the particle diameter of the pigment, the median diameter d50 in the ink is preferably 50 nm or more and 300 nm or less. The median diameter can be measured with a laser diffraction scattering measurement device.

When the pigment concentration and the pigment concentration ratio are larger than the above range, the weather resistance is good, but the color developability is poor and the printed matter becomes dark in color tone, which is not suitable.
If the pigment concentration and the pigment concentration ratio are smaller than the above range, the color developability is good, but the weather resistance is poor, causing problems such as peeling of the ink film on the tarpaulin and a large change in color difference.

Further, in the pigment, the organic pigment residue described in the color index includes a sulfuric acid group, a sulfonic acid amide group, a sulfonic acid group and salts thereof, a phthalimide group, a phthalimidomethyl group, an amino group, a triazine group, and the like. A conventionally known pigment derivative into which a substituent is introduced, for example, an azo-based, phthalocyanine-based, quinacridone-based pigment derivative (synergist) may preferably be included.

These pigment derivatives may be used in the form of powder or wet cake. Also, the amount of the pigment derivative to be blended is preferably 3 to 60% by weight, more preferably 5 to 20% by weight, based on the pigment.

Examples of the pigment derivative include phthalocyanine sulfonic acid, phthalimidomethylquinacridone, phthalimidomethylated 3,10-dichloroquinacridone, Solsperse 5000, Solsperse 12000 and Solsperse 22000 manufactured by Lubrizol, and BYK-Synergist 2100 manufactured by BYK-Chemie.

<<Polymerizable compound (hereinafter also referred to as monomer)>>
The active energy ray-polymerizable compound of the present invention is a reactive compound having in its molecule an ethylenically unsaturated bond that undergoes a polymerization reaction when irradiated with an active energy ray. As shown below, the active energy ray-polymerizable compound includes various reactive monomers, reactive oligomers, and the like. These active energy ray-polymerizable compounds may be used singly in each ink. Well, you may use it in combination of 2 or more types. Moreover, the active energy ray-polymerizable compounds used between the inks constituting the active energy ray-curable ink set of the present invention may be the same or different.

The polymerizable compound, for example, depending on the number of ethylenically unsaturated bonds contained in the molecule, a monofunctional monomer having an ethylenically unsaturated bond number of 1, a bifunctional monomer having an ethylenically unsaturated bond number of 2, and polyfunctional monomers having 3 or more ethylenically unsaturated bonds.

Specific examples of monofunctional monomers include stearyl acrylate, acryloylmorpholine, tridecyl acrylate, lauryl acrylate, N,N-dimethylacrylamide decyl acrylate, isodecyl acrylate, isobornyl acrylate, benzyl acrylate, phenoxyethyl acrylate, di Cyclopentanyl acrylate, dicyclopentenyl acrylate, isooctyl acrylate, octyl acrylate, dicyclopentenyloxyethyl acrylate, cyclohexyl acrylate, N-vinylcaprolactam, isoamyl acrylate, 2-ethylhexyl-diglycol acrylate, neopentyl glycol acrylic acid benzoic acid ester, N-vinyl-2-pyrrolidone, N-vinylimidazole, tetrahydrofurfuryl acrylate, methoxydipropylene glycol acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, cyclic tri Methylolpropane formal acrylate, ethoxy-diethylene glycol acrylate, and 2-(2'-vinyloxyethoxy) ethyl acrylate, etc., and those modified with alkylene glycol chains such as ethylene glycol chains and propylene glycol chains are also included. can be done. Methacrylates can also be used in addition to acrylates.

Particular preference is given to isobornyl acrylate, benzyl acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, ethoxy-diethylene glycol acrylate.

Specific examples of bifunctional monomers include 1,10-decanediol diacrylate, 2-methyl-1,8-octanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, 1,9-nonanediol diacrylate, 1,8-octanediol diacrylate, 1,7-heptanediol diacrylate, polytetramethylene glycol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 1,6 - hexanediol diacrylate, EO-modified 1,6-hexanediol diacrylate, triethylene glycol diacrylate, neopentyl glycol diacrylate, neopentyl glycol hydroxypivalate diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene Glycol diacrylate, EO-modified neopentyl glycol diacrylate, PO-modified neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, 1,4-butanediol diacrylate, and dipropylene glycol diacrylate. Among these, CH2=CH-COO-CnH2n-OOC-CH=CH2 (n is an integer of 4 to 12) is preferable from the viewpoint of further improving weather resistance. Besides acrylates, methacrylates may also be mentioned.

Further preferred are 1,6-hexanediol diacrylate, EO-modified 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, and EO-modified neopentyl glycol diacrylate.

Polyfunctional monomers can be used to improve curability and strength of printed films, and specific examples include trimethylolpropane triacrylate, pentaerythritol triacrylate, glycerin triacrylate, tetramethylolmethane triacrylate, penta Erythritol tetraacrylate, diglycerin tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, EO-modified trimethylolpropane triacrylate and dipentaerythritol hexaacrylate, etc., and these are ethylene glycol chains, propylene glycol chains, etc. Those modified with an alkylene glycol chain can also be used. Besides acrylates, methacrylates may also be mentioned.

Trimethylolpropane triacrylate and EO-modified trimethylolpropane triacrylate are preferred.

Reactive oligomers (hereinafter also referred to as oligomers) can be used to improve the strength of the printed layer and reduce the volume shrinkage of the printed layer during curing. In the present invention, the reactive oligomer preferably has a molecular weight of 1000 g/mol or more.

Specific examples of reactive oligomers include amino resin acrylates, urethane acrylates, epoxy acrylates, silicone acrylates, polyester acrylates, and polybutadiene acrylates. Among these, urethane acrylates are preferred from the viewpoint of weather resistance and adhesion, and aliphatic urethane acrylates having no aromatic ring are more preferred. Methacrylates can also be used in addition to acrylates.

In the active energy ray-curable inkjet ink set of the present invention, each of the cyan ink, magenta ink, and yellow ink preferably contains 30 to 90% by mass of the active energy ray-polymerizable compound. The content of the active energy ray-polymerizable compound in each ink is within a range in which the viscosity of the ink, curing upon irradiation with an active energy ray, and coloring power can be obtained satisfactorily.

≪Polymerization initiator≫
The ink set of the present invention contains a photopolymerization initiator. The photopolymerization initiator has a function of initiating polymerization of the active energy ray-polymerizable compound described above. The content of the photopolymerization initiator in each ink is preferably 1 to 25% by mass, more preferably 3 to 15% by mass.

Examples of the photopolymerization initiator include α-aminoketone-based compounds, benzophenone-based compounds, acetophenone-based compounds, thioxanthone-based compounds, and phosphine oxide-based compounds. It is preferable that the absorption wavelengths of the photopolymerization initiator overlap as much as possible. Furthermore, in order to accelerate the initiation reaction of the photopolymerization initiator, it is also possible to use an auxiliary agent such as a photosensitizer.

Specific examples of photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenylpropane- 1-one, benzophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-( 2-hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, phenylglyoxylic acid methyl ester, 2-methyl-1-[4-(methylthio)phenyl]-2 -morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4- morpholin-4-yl-phenyl)-butan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl- pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1- [9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime), 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, etc. are mentioned. Among these, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is preferable from the viewpoint of ink curability. In addition, these photoinitiators may be used individually by 1 type, and may be used in combination of 2 or more types.

The wavelength of the active energy ray to be irradiated preferably overlaps with the absorption wavelength of the photopolymerization initiator. It is preferably between 360 and 425 nm.

(Pigment dispersant)
A pigment dispersant is preferably used for the pigment for the purpose of enhancing dispersion stability in the ink. The content of the pigment dispersant is, for example, 0.1 to 5% by mass in the total mass of the ink composition, preferably 5 to 100% by mass, particularly 8 to 80% by mass, based on the pigment. preferable. Pigment dispersants may be used singly or in combination of two or more.

Specific examples of the pigment dispersant include:
ANTI-TERRA-U, ANTI-TERRA-U100,
ANTI-TERRA-204, ANTI-TERRA-205,
DISPERBYK-101, DISPERBYK-102,
DISPERBYK-103, DISPERBYK-106,
DISPERBYK-108, DISPERBYK-109,
DISPERBYK-110, DISPERBYK-111,
DISPERBYK-112, DISPERBYK-116,
DISPERBYK-130, DISPERBYK-140,
DISPERBYK-142, DISPERBYK-145,
DISPERBYK-161, DISPERBYK-162,
DISPERBYK-163, DISPERBYK-164,
DISPERBYK-166, DISPERBYK-167,
DISPERBYK-168, DISPERBYK-170,
DISPERBYK-171, DISPERBYK-174,
DISPERBYK-180, DISPERBYK-182,
DISPERBYK-183, DISPERBYK-184,
DISPERBYK-185, DISPERBYK-2000,
DISPERBYK-2001, DISPERBYK-2008,
DISPERBYK-2009, DISPERBYK-2020,
DISPERBYK-2025, DISPERBYK-2050,
DISPERBYK-2070, DISPERBYK-2096,
DISPERBYK-2150, DISPERBYK-2155,
DISPERBYK-2163, DISPERBYK-2164,
BYK-P104, BYK-P104S, BYK-P105,
BYK-9076, BYK-9077, BYK-220S, BYKJET-9150, BYKJET-9151 (manufactured by BYK-Chemie Japan),
Solsperse 3000, Solsperse 5000,
Solsperse 9000, Solsperse 11200,
Solsperse 13240, Solsperse 13650,
Solsperse 13940, Solsperse 16000,
Solsperse 17000, Solsperse 18000,
Solsperse 20000, Solsperse 21000,
Solsperse 24000SC, Solsperse 24000GR,
Solsperse 26000, Solsperse 27000,
Solsperse 28000, Solsperse 32000,
Solsperse 32500, Solsperse 32550,
Solsperse 32600, Solsperse 33000,
Solsperse 34750, Solsperse 35100,
Solsperse 35200, Solsperse 36000,
Solsperse 36600, Solsperse 37500,
Solsperse 38500, Solsperse 39000,
Solsperse 41000, Solsperse 54000,
Solsperse 55000, Solsperse 56000,
Solsperse 71000, Solsperse 76500,
Solsperse X300 (manufactured by Lubrizol),
Disparlon DA-7301, Disparlon DA-325, Disparlon DA-375, Disparlon DA-234 (manufactured by Kusumoto Kasei Co., Ltd.),
Floren AF-1000, Floren DOPA-15B, Floren DOPA-15BHFS, Floren DOPA-17HF, Floren DOPA-22, Floren DOPA-33, Floren G-600, Floren G-700, Floren G-700AMP, Floren G-700DMEA, Floren G-820, Floren G-900, Floren GW-1500, Floren KDG-2400, Floren NC-500, Floren WK-13E (manufactured by Kyoeisha Chemical Co., Ltd.),
TEGO Dispers610, TEGO Dispers610S,
TEGO Dispers 630, TEGO Dispers 650,
TEGO Dispers 652, TEGO Dispers 655,
TEGO Dispers662C, TEGO Dispers670,
TEGO Dispers 685, TEGO Dispers 700,
TEGO Dispers710, TEGO Dispers740W,
LIPOTIN A, LIPOTIN BL,
LIPOTIN DB, LIPOTIN SB (manufactured by Evonik Degussa),
PB821, PB822, PN411, PA111 (manufactured by Ajinomoto Fine-Techno Co., Inc.),
Texahall 963, Texahall 964, Texahall 987, Texahall P60, Texahall P61, Texahall P63, Texahall 3250, Texahall SF71, Texahall UV20, Texahall UV21 (manufactured by Cognis),
BorchiGenSN88, BorchiGen0451 (above, manufactured by Bosius) and the like.

(Polymerization inhibitor)
Polymerization inhibitors used in the present invention include, for example, hydroquinone, methoquinone, di-t-butylhydroquinone, p-methoxyphenol, butylhydroxytoluene, nitrosamine salts, and the like. You may add in the range of 2 mass %.

(Additive)
Other ingredients include light stabilizers, storage stabilizers (silane coupling agents), antioxidants, surface conditioners, plasticizers, rust inhibitors, high boiling point solvents, non-reactive polymers, fillers, pH adjusters, Additives such as antifoaming agents, charge control agents, stress relaxation agents, penetrating agents, light guiding agents, glittering agents, magnetic agents and phosphors may be used as necessary.

<Manufacturing method for active energy ray-curable inkjet ink set>
The ink set of the present invention is prepared by first mixing a pigment, a part of a polymerizable compound, and a dispersant to produce a dispersion, and then adding a polymerizable compound, a photopolymerization initiator, and appropriate additives (e.g., oligomers, ultraviolet-absorbing agent, silane coupling agent, surface control agent) and a polymerizable compound composition prepared by mixing.

(ink set)
The active energy ray-curable inkjet ink set of the present invention is a set including yellow ink, magenta ink, cyan ink, and color inks such as black ink and white ink that are usually added to active energy ray-curable inkjet ink sets. may In addition, dark colors and light colors of the same series may be added to each color, and in addition to magenta, light magenta, dark red, light cyan in addition to cyan, dark blue, and black In addition, light gray, light black, dark matte black, etc. may be added.

Each ink of the ink set of the present invention preferably has a viscosity at 50° C. of 5 to 15 mPa·s, more preferably 5 to 10 mPa·s. This viscosity can be measured using a Brookfield viscometer,

Each ink of the ink set of the present invention preferably has a surface tension of 25 to 40 mN/m at 25°C. The surface tension was measured by the platinum plate method (automatic surface tensiometer CBVP-Z manufactured by Kyowa Interface Science).
Each ink of the ink set of the present invention preferably has a specific gravity of 1.06 to 1.08 at 25°C.

The ink set of the present invention can be suitably applied to printing by an inkjet printer for the purpose of printing on outdoor articles such as sign displays. After printing with an inkjet printer, by curing the printed material by irradiating it with an active energy ray, it is possible to form a printed material with good weather resistance.

(Curing reaction)
The active energy ray-curable inkjet ink set of the present invention undergoes a curing reaction by irradiation with light such as an active energy ray, preferably ultraviolet rays. As a light source for ultraviolet light, curing can be performed without any problem if it is a light source normally used for UV-curable inkjet ink, such as a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, or the like. . For example, commercially available lamps such as H lamp, D lamp and V lamp manufactured by Fusion System can be used.

In addition, when using UV-LEDs, which have been increasingly adopted in recent years, or ultraviolet light emitting semiconductor elements such as ultraviolet light emitting semiconductor lasers, it is possible to appropriately select and use a highly sensitive photopolymerization initiator or polymerizable compound. can. The active energy ray preferably has a dominant wavelength of 360 to 425 nm.

(Base material)
A preferred substrate to which the ink set of the present invention is applied is a vinyl chloride sheet or tarpaulin. The vinyl chloride sheet or tarpaulin is characterized by having a printed layer formed from the active energy ray-curable ink set described above, and exhibits excellent weather resistance even when exposed outdoors for a long period of time.

The printed matter of the present invention is not particularly limited except for using the active energy ray-curable ink set described above, and can be produced according to a conventional method. By printing on a vinyl chloride sheet or tarpaulin with an inkjet printer and curing the printed matter by irradiation with active energy rays, a printed matter having a printed layer with excellent weather resistance can be produced.

The printed matter is not particularly limited, but for example, plastics, glasses, metals, ceramics such as pottery, building materials such as inorganic ceramic materials, concrete blocks, paper coated with resin on the surface, sign displays It also includes materials used for outdoor articles such as

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

<Ink adjustment>
Each mixture is obtained according to the formulation shown in Table 1, mixed with the desired ink composition, kneaded in a bead mill to homogenize, and filtered through a filter having a pore size of about 1/10 of the nozzle diameter of the inkjet printer head. The ink was produced by

<Sample adjustment>
Using a commercially available polyvinyl chloride sheet and tarpaulin as the base material, 100% solid printed images (size 30 mm x 30 mm) of each color of Y, M, C, and K were produced from the prepared ink set using a multi-pass inkjet printer. and used as a sample.

<Color development of printed matter>
The L value of each sample was measured by a color difference meter (Spectro Eye manufactured by X-Rite), and the color development property was determined according to the following criteria. Image sharpness was evaluated by the degree of color development.
Y color ○: L value 80 or more ×: L value less than 80 M color ○: L value 40 or more ×: L value less than 40 C color ○: L value 45 or more ×: L value less than 45

<Weather resistance evaluation>
Each sample prepared above was tested for 1500 hours using a Sunshine Weatherometer (S80 manufactured by Suga Test Instruments Co., Ltd.). The color difference ΔE from the initial stage of the printed matter on the vinyl chloride sheet was measured with a color difference meter (Spectro Eye manufactured by X-Rite). In addition, the print on the tarpaulin was visually observed for peeling of the ink film compared to the initial state.

<Weather resistance (vinyl chloride sheet printed matter)>
≪Color difference≫
○: Less than △E10 ×: △E10 or more

<Weather resistance (tarpaulin printed matter)>
≪Presence or absence of peeling≫
○: Peeling of ink film ×: No peeling of ink film

As shown in Tables 1 to 9, the present invention provides excellent weather resistance and image sharpness.

Claims (6)

An active energy ray-curable inkjet ink set comprising at least yellow ink, magenta ink, cyan ink, black ink and white ink ,
Each of the inks contains at least a pigment and a polymerizable compound, the cyan ink contains 1.3 to 2.8% by weight of the cyan pigment, and the magenta ink contains 2.7 to 4.5% by weight of the cyan pigment. of magenta pigment, the yellow ink contains 2.0 to 5.0% by mass of yellow pigment, the black ink contains 1.6 to 3.0% by mass of black pigment, and the The white ink contains 5 to 15% by mass of white pigment,
The amount of each pigment is cyan pigment:magenta pigment:yellow pigment: black pigment:white pigment =1:1.3-2.0:1.5-2.4 :1.1-2.1:1. 4 to 4.5 (mass ratio),
Each ink has a viscosity of 5 to 15 mPa·s at 50° C., a surface tension of 25 to 40 mN/m at 25° C. , and a specific gravity of 1.06 to 1.08 at 25° C.
An active energy ray-curable inkjet ink set in which each of the inks is applied to a PVC sheet or tarpaulin substrate . 2. The active energy ray-curable inkjet ink set according to claim 1, wherein the yellow pigment is a nickel complex compound having an azo skeleton or a yellow pigment having a quinoxaline skeleton, and the magenta pigment is a magenta pigment having a quinacridone skeleton. The yellow pigment is C.I. I. Pigment Yellow 150, 213, said magenta pigment being C.I. I. Pigment Red 122, 202, C.I. I. 3. The active energy ray-curable inkjet ink set according to claim 1, wherein the active energy ray-curable ink set is selected from Pigment Violet 19. The active energy ray-curable inkjet ink set includes:
C. I. having a black ink containing a black pigment selected from Pigment Black 7 and 35;
C. I. 4. The active energy ray-curable inkjet ink set according to claim 1, comprising a white ink containing a white pigment selected from Pigment White 6, 18 and 21. 5. The active energy ray-curable inkjet ink set according to claim 1, wherein the polymerizable compound comprises a urethane acrylate oligomer having a molecular weight of 1000 g/mol or more. Each ink contains a pigment dispersant, and the content of the pigment dispersant is 0.1 to 5% by mass based on the total mass of the ink composition, and is in the range of 5 to 80% by mass based on the pigment. The active energy ray-curable inkjet ink set according to any one of claims 1 to 5.