JP6058058B2 - Ink set, printed matter and method for producing the same - Google Patents

Description

  The present invention relates to an ink set, a method for producing a printed matter using the ink set, and a printed matter obtained by the production method. More specifically, the present invention reduces the adhesion of a printing layer formed from an active energy ray-curable inkjet ink. The present invention relates to an ink set that can express a high-definition image without using it. The active energy ray-curable ink-jet ink is an ink composition for an ink jet printer, and means an ink composition that can be cured by irradiation with active energy rays such as ultraviolet rays.

  In recent years, various active energy ray-curable inkjet inks have been proposed, and ink sets including color inks and white inks and ink sets including color inks and clear inks are known (see, for example, Patent Documents 1 to 3). ). The white ink is printed before the color ink is printed for the purpose of hiding the base such as the base material. In addition, clear ink can be used for the purpose of exerting a primer function such as improving the adhesion of the printing layer and fixing the color ink, and protects the image printed before the color ink is printed or the image expressed by the color ink. It can be used for purposes, and is printed after printing with color ink. However, when color ink droplets are ejected onto a print layer formed from clear ink or white ink, if the ink droplets are compatibilized, bleeding occurs in the image, resulting in a fine print. There was a problem of lacking.

  In response to this problem, Patent Document 4 describes an ink jet ink set composed of color ink and white ink. By making the surface tension of white ink lower than the surface tension of color ink, a transparent recording medium or brightness It is described that a high-definition image excellent in visibility can be obtained even for a recording medium having a low image quality.

JP 2014-196497 A JP 2014-177572 A JP 2013-181163 A Japanese Patent No. 4877224

  According to the ink set described in Patent Document 4, although a high-definition image can be obtained, it is actually necessary to use silicone oil as a surface conditioner in order to reduce the surface tension of the white ink. However, when silicone oil is blended in the ink, there is a problem of reducing the adhesion of the resulting printed layer.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems of the prior art and provide an ink set that can express a high-definition image without reducing the adhesion of a printing layer formed from an active energy ray-curable inkjet ink. There is.

  Another object of the present invention is to provide a printed material capable of expressing a high-definition image without reducing the adhesion of the printed layer to the substrate or the undercoat film, and a method for producing the printed material.

  The present inventor examined the cause of the decrease in the adhesion of the printed layer when blending the silicone oil into the ink. The reason is that the silicone oil has the ability to greatly suppress the interaction between molecules. The silicone oil ability effectively works to reduce the surface tension of the ink, but the silicone oil in the printing layer also exhibits the ability. For this reason, if there is a printing layer formed from white ink or clear ink containing silicone oil between the printing layer formed from the base material and the color ink, the adhesion between the layers is lowered.

  Therefore, as a result of intensive studies to achieve the above object, the present inventor includes an acrylic surface conditioner in place of an ink containing a silicone surface conditioner in an ink set composed of an active energy ray-curable inkjet ink. When the ink is used as a clear ink or a white ink, a high-definition image can be sufficiently expressed even when the surface tension of the color ink is higher than the surface tension of the color ink, and sufficient adhesion of the resulting printed layer can be secured. As a result, the present invention has been completed.

That is, the ink set of the present invention is an ink set formed by combining one or more color inks with a clear ink or a white ink,
The color ink, clear ink and white ink are active energy ray-curable inkjet inks,
The color ink contains at least a colorant other than a white colorant,
The white ink contains at least a white colorant and an acrylic surface conditioner,
The clear ink contains at least an acrylic surface conditioner,
When the color ink is composed of one type, the surface tension of the clear ink and the white ink is higher than the surface tension of the color ink,
When the color ink includes a plurality of color inks, the surface tension of the clear ink and the white ink is higher than the surface tension of the color ink having the lowest surface tension among the color inks.

  In a preferred example of the ink set of the present invention, the acrylic surface conditioner has an SP value of 8.5 to 10.5 and a weight average molecular weight of 3,000 to 100,000.

  In another preferred embodiment of the ink set of the present invention, the acrylic surface conditioner is at least one selected from the group consisting of lauryl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. It is a polymer containing an acrylate monomer as a structural unit.

  In another preferred embodiment of the ink set of the present invention, the color ink, the clear ink, and the white ink have an ink viscosity at 40 ° C. of 5 to 15 mPa · s and an ink surface tension at 25 ° C. of 25 to 40 mN. / M.

  In another preferred embodiment of the ink set of the present invention, a printing layer comprising a first layer formed from the clear ink or white ink and a second layer formed from the color ink on the first layer is provided. It is an ink set for forming.

  Moreover, the manufacturing method of the 1st printed matter of this invention is characterized by including the process of discharging ink to the base-material surface by an inkjet printer provided with said ink set, and forming a printing layer.

  Furthermore, in the second method for producing a printed matter of the present invention, an ink is applied onto the undercoat coating film by applying an undercoat paint to the surface of the substrate to form an undercoat paint film, and an ink jet printer provided with the ink set described above. And a step of forming a printed layer by discharging.

  In a preferred example of the first and second printed matter production methods of the present invention, the method further includes a step of applying a top coat onto the print layer and forming a top coat film so as to cover the print layer.

  Furthermore, the printed matter of the present invention is obtained by the above-described method for producing a printed matter.

  According to the ink set of the present invention, it is possible to provide an ink set that can express a high-definition image without reducing the adhesion of a printing layer formed from an active energy ray-curable inkjet ink.

  According to the first method for producing a printed matter of the present invention, it is possible to provide a printed matter that can express a high-definition image without reducing the adhesion of the printed layer to the substrate. In addition, according to the second method for producing a printed matter of the present invention, it is possible to provide a printed matter that can express a high-definition image without reducing the adhesion of the printed layer to the undercoat coating film. According to the printed matter of the present invention, a high-definition image can be expressed without reducing the adhesion of the printed layer.

  Hereinafter, the ink set of the present invention will be described in detail. The ink set of the present invention is an ink set formed by combining one or more color inks with a clear ink or a white ink. That is, the ink set of the present invention is an ink set including color ink and clear ink, or an ink set including color ink and white ink. Color inks may be used singly or in combination.

  In the ink set of the present invention, when the color ink is composed of one type, the surface tension of the clear ink and the white ink is higher than the surface tension of the color ink, and when the color ink is composed of a plurality of color inks, the clear ink and the white ink Is higher than the surface tension of the color ink having the lowest surface tension among the color inks. The ink set of the present invention includes one of a clear ink and a white ink, but a color ink whose surface tension is lower than the surface tension of the ink usually tends to cause compatibilization of ink droplets. If the ink set includes color ink having a surface tension lower than that of the clear ink and the white ink, it becomes difficult to express a high-definition image. However, in the ink set of the present invention, as will be described later, since the clear ink and the white ink contain an acrylic surface conditioner, the ink set includes a color ink whose surface tension is lower than the surface tension of the clear ink and the white ink. Even so, a high-definition image can be sufficiently expressed.

  In the ink set of the present invention, the clear ink and the white ink and the color ink whose surface tension is lower than the surface tension of the clear ink and the white ink have a difference in surface tension at 25 ° C. of 0.1 to 5.0 mN. / M is preferably within the range of 0.1 to 3.0 mN / m. If the difference in surface tension is too large, it may be difficult to express a high-definition image.

  In the ink set of the present invention, the surface tension of the ink is measured by a plate method, and the measurement temperature is 25 ° C.

  In the ink set of the present invention, the color ink is an active energy ray-curable inkjet ink containing at least a colorant other than a white colorant. The colorant used in the color ink is not particularly limited as long as it is other than a white colorant, and examples thereof include various colorants such as cyan, magenta, yellow, and black. Colorants are generally classified as dyes or pigments, but are preferably pigments from the viewpoint of weather resistance. In addition, content of a coloring agent is 0.1-10 mass% in the total mass of a color ink, for example. Moreover, a coloring agent may be used individually by 1 type, and may be used in combination of 2 or more type.

Specific examples of the colorant used in the color ink include
C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 14, 15, 16, 17, 24, 32, 34, 35, 36, 37, 41, 42, 43, 49, 53, 55, 60, 61, 62, 63, 65, 73, 74, 75, 77, 81, 83, 87, 93, 94, 95, 97, 98, 99, 100, 101, 104, 105, 106, 108, 109, 110, 111, 113, 114, 116, 117, 119, 120, 123, 124, 126, 127, 128, 129, 130, 133, 138, 139, 150, 151, 152, 153, 154, 155, 165, 167, 168, 169, 170, 172, 173, 174, 175, 176, 179, 180, 181, 182, 183, 184, 185, 91,193,194,199,205,206,209,212,213,214,215,219,
C. I. Pigment Orange 1, 2, 3, 4, 5, 13, 15, 16, 17, 19, 20, 21, 24, 31, 34, 36, 38, 40, 43, 46, 48, 49, 51, 60, 61, 62, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 81,
C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 21, 22, 23, 31, 32, 38, 41, 48, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49, 52, 52: 1, 52: 2, 53: 1, 54, 57: 1, 58, 60: 1, 63, 64: 1, 68, 81: 1, 83, 88, 89, 95, 101, 104, 105, 108, 112, 114, 119, 122, 123, 136, 144, 146, 147, 149, 150, 164, 166, 168, 169, 170, 171, 172, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 187, 188, 190, 193, 194, 200, 202, 206, 20 208, 209, 210, 211, 213, 214, 216, 220, 220, 221, 224, 226, 237, 238, 239, 242, 245, 247, 248, 251, 253, 254, 255, 256, 257 258, 260, 262, 263, 264, 266, 268, 269, 270, 271, 272, 279,
C. I. Pigment Violet 1, 2, 3, 3: 1, 3: 3, 5: 1, 13, 15, 16, 17, 19, 23, 25, 27, 29, 31, 32, 36, 37, 38, 42, 50,
C. I. Pigment Blue 1, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 5, 15: 6, 16, 17: 1, 24, 24: 1, 25, 26, 27, 28, 29, 36, 56, 60, 61, 62, 63, 75, 79, 80,
C. I. Pigment Green 1, 4, 7, 8, 10, 15, 17, 26, 36, 50,
C. I. Pigment Brown 5, 6, 23, 24, 25, 32, 41, 42,
C. I. Pigment Black 1, 6, 7, 9, 10, 11, 20, 31, 32, 34,
Examples include aluminum flakes, glass flakes, and hollow particles.

Among these, from the viewpoint of weather resistance and color reproducibility of the printed layer,
C. I. PigmentBlack7,
C. I. PigmentBlue 15: 3, C.I. I. Pigment Blue 15: 4, C.I. I. PigmentBlue 28,
C. I. PigmentRed101, C.I. I. PigmentRed122,
C. I. PigmentRed 202, C.I. I. PigmentRed254,
C. I. PigmentRed282,
C. I. PigmentViolet 19,
C. I. Pigment Yellow 42, C.I. I. Pigment Yellow 120,
C. I. Pigment Yellow 138, C.I. I. Pigment Yellow 139, C.I. I. Pigment Yellow 150, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 213 is preferable.

  In the ink set of the present invention, the white ink is an active energy ray-curable inkjet ink containing at least a white colorant and an acrylic surface conditioner. The colorant used in the white ink is limited to a white colorant. I. Pigment White 1, 2, 4, 5, 6, 7, 11, 12, 18, 19, 21, 22, 23, 26, 27, 28, etc., from the viewpoint of weather resistance and color reproducibility of the printed layer , C.I. I. PigmentWhite 7 is preferable. These white colorants may be used alone or in combination of two or more. As described above, the colorant is preferably a pigment from the viewpoint of weather resistance. Moreover, content of a white colorant is 0.1-10 mass% in the total mass of white ink, for example.

  When the colorant used for the color ink and the white ink is a pigment, the pigment particles dispersed in the ink have a volume average particle diameter of 0.05 to 0.4 μm and a volume from the viewpoint of ejection stability. The maximum particle size is preferably 0.2-1 μm. When the volume average particle diameter is larger than 0.4 μm and the volume maximum particle diameter is larger than 1 μm, it tends to be difficult to stably eject ink. The volume average particle diameter and the volume maximum particle diameter can be measured by a measuring instrument using a dynamic light scattering method.

  In the ink set of the present invention, the clear ink is an active energy ray-curable inkjet ink containing at least an acrylic surface conditioner. The clear ink does not contain a colorant.

  The acrylic surface conditioner used for the clear ink and the white ink is a surface conditioner having a poly (meth) acrylate skeleton, and can improve the leveling property of a printing layer formed from the clear ink and the white ink. . In addition, acrylic surface conditioners have a lower ability to suppress intermolecular interactions than silicone surface conditioners such as silicone oils, so even if an acrylic surface conditioner is added to the ink, it can be obtained. It is possible to prevent a decrease in the adhesion of the printed layer. Furthermore, since the acrylic surface conditioner in the printing layer tends to be present on the surface of the printing layer, the color ink droplets are compatible with each other on the printing layer formed of clear ink or white ink. And high-definition images can be sufficiently expressed.

  The acrylic surface conditioner is not particularly limited, but constitutes at least one acrylate monomer selected from the group consisting of lauryl (meth) acrylate, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. The polymer is preferably contained as a unit. In addition, it is preferable that the structural unit which consists of these acrylate monomers occupies 50-100 mass% of a polymer. The polymer can contain a monomer other than the acrylate monomer as a constituent unit. For example, the polymer may contain at least one carboxyl group-containing monomer selected from the group consisting of acrylic acid and methacrylic acid as a constituent unit. The polymer may contain a hydroxyl group-containing monomer such as hydroxyethyl acrylate as a structural unit. The polymer may contain an alkyl (meth) acrylate or alkenyl (meth) acrylate other than the above acrylate monomer as a structural unit. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) ) Acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, isodecyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate Etc. These monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  The acrylic surface conditioner preferably has an SP value of 8.5 to 10.5. When the SP value (dissolution parameter) of the acrylic surface conditioner is less than 8.5 or more than 10.5, there is a problem in compatibility in the clear ink and the white ink, and the ejection stability is lowered. There is. The SP value is a standard for determining compatibility, and there are various calculation methods and actual measurement methods. In the present invention, the SP value was obtained using the SP value by the vapor pressure method proposed by Hoy. It means a value calculated according to the method described in the literature [KL Hoy, J. Paint Technology, 42, [541], 76 (1970)] using molecular attraction constant. Specifically, the SP value is represented by δ = (dΣG) / M, d is the density of the polymer, M is the molecular weight of the basic structural unit of the polymer, and ΣG is an atom (group) present in the basic structural unit. Is the sum of molecular attraction constants G corresponding to.

  The acrylic surface conditioner preferably has a polystyrene-equivalent weight average molecular weight of 3,000 to 100,000. If the weight average molecular weight of the acrylic surface conditioner is less than 3,000, the leveling property may not be sufficiently improved. If the weight average molecular weight exceeds 100,000, the compatibility in the clear ink and the white ink may be insufficient. Problems may occur, and the discharge stability may decrease. In the present invention, the weight average molecular weight is a value measured by gel permeation chromatography (GPC), and polystyrene is used as the standard substance.

  In the clear ink and the white ink, the content of the acrylic surface conditioner is preferably 0.01 to 5% by mass, and more preferably 0.02 to 2% by mass. If the content of the acrylic surface conditioner is less than 0.01% by mass, the leveling property cannot be sufficiently improved, and the image definition may be lowered. Moreover, when content of the said acrylic type surface conditioning agent exceeds 5 mass%, a printing layer may become a hardening defect.

  In the ink set of the present invention, the printed layer formed from the clear ink or the white ink can sufficiently ensure adhesion to the substrate or the undercoat film, and is formed from the clear ink or the white ink. A high-definition image can be expressed by printing an image using color ink on the print layer. For this reason, the ink set of the present invention is an ink for forming a printing layer including a first layer formed from a clear ink or a white ink and a second layer formed from a color ink on the first layer. A set is preferred.

  The color ink, clear ink, and white ink are active energy ray-curable inkjet inks, and preferably contain a radical polymerizable monomer having 1 to 2 functional groups. By using a radical polymerizable monomer having 1 to 2 functional groups, the curability of the print layer and the strength of the print layer can be controlled. In addition, in this invention, a functional group refers to the functional group which shows the reactivity at the time of active energy ray irradiation. The radical polymerizable monomer preferably has a molecular weight of 1,000 or less.

  The radical polymerizable monomer having 1 to 2 functional groups is not particularly limited, and examples thereof include a monofunctional monomer having 1 functional group and a bifunctional monomer having 2 functional groups as described later. . In addition, the said radically polymerizable monomer may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the monofunctional monomer include stearyl acrylate, acryloylmorpholine, tridecyl acrylate, lauryl acrylate, N, N-dimethylacrylamide, decyl acrylate, phenoxyethyl acrylate, isodecyl acrylate, isobornyl acrylate, and dicyclopentanyl. Acrylate, dicyclopentenyl acrylate, isooctyl acrylate, octyl acrylate, dicyclopentenyloxyethyl acrylate, cyclohexyl acrylate, N-vinylcaprolactam, isoamyl acrylate, 2-ethylhexyl-diglycol acrylate, EO (ethylene oxide) modified 2-ethylhexyl acrylate, Neopentyl glycol acrylic acid benzoate, N-vinyl-2 Pyrrolidone, N-vinylimidazole, tetrahydrofurfuryl acrylate, methoxydipropylene glycol acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, cyclic trimethylolpropane formal acrylate, ethoxy- Examples include diethylene glycol acrylate and 2- (2′-vinyloxyethoxy) ethyl acrylate. Among these, isobornyl acrylate, phenoxyethyl acrylate, methoxydipropylene glycol acrylate, cyclohexyl acrylate, ethoxy-diethylene glycol acrylate, and tetrahydrofurfuryl acrylate are preferable. In addition, these monofunctional monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the bifunctional monomer 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, neopentyl glycol diacrylate, hydroxypivalate neopentyl glycol diacrylate, tripropylene glycol diacrylate, 1,4-butanediol diacrylate, dipropylene glycol diacrylate, etc. It is. Among these, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate and neopentyl glycol diacrylate are preferable. In addition, these bifunctional monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the ink set of the present invention, the content of the radical polymerizable monomer having 1 to 2 functional groups in the color ink, the clear ink, and the white ink is from the viewpoint of controlling the curability of the print layer and the strength of the print layer. 50 to 90% by mass is preferable.

  In the color ink, clear ink, and white ink, a trifunctional or higher polyfunctional radical polymerizable monomer having 3 or more functional groups may be used in order to increase the curability of the print layer and the strength of the print layer. The trifunctional or higher polyfunctional radical polymerizable monomer preferably has a molecular weight of less than 2,000. In addition, content of the polyfunctional radically polymerizable monomer more than trifunctional is 1-20 mass% in an ink, for example.

  Examples of the trifunctional or higher polyfunctional radical polymerizable monomer include trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated glycerin triacrylate, and tetramethylolmethane. Examples include triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, EO-modified diglycerin tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate. In addition, these polyfunctional radically polymerizable monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

In the color ink, clear ink, and white ink, an acrylate oligomer may be used in order to improve the strength of the printing layer. An acrylate oligomer is an oligomer having one or more acryloyloxy groups (CH ₂ ═CHCOO—), and the number of functional groups is preferably 3-6. The acrylate oligomer preferably has a molecular weight of 2,000 to 20,000. In addition, this molecular weight is a weight average molecular weight of polystyrene conversion. Specific examples of the acrylate oligomer include aminoacrylate oligomer [acrylate oligomer having a plurality of amino groups (-NH ₂ )], urethane acrylate oligomer [acrylate oligomer having a plurality of urethane bonds (-NHCOO-)], epoxy acrylate oligomer [ Acrylate oligomer having a plurality of epoxy groups], silicone acrylate oligomer [acrylate oligomer having a plurality of siloxane bonds (—SiO—)], ester acrylate oligomer [acrylate oligomer having a plurality of ester bonds (—COO—)] and butadiene acrylate oligomer [butadiene Acrylate oligomer having a plurality of units] and the like. Among these, urethane acrylate oligomers are preferable from the viewpoint of weather resistance and adhesion, and aliphatic urethane acrylate oligomers having no aromatic ring in the structure are more preferable. In addition, content of an acrylate oligomer is 1-10 mass% in an ink, for example.

Specific examples of the acrylate oligomer include the following. In addition, these acrylate oligomers may be used individually by 1 type, and may be used in combination of 2 or more type.
Beam set 502H, beam set 505A-6, beam set 550B, beam set 575, beam set AQ-17 (manufactured by Arakawa Chemical Industries),
UA-306H, UA-306I, UA-510H, UF-8001G (manufactured by Kyoeisha Chemical Co., Ltd.),
CN929, CN940, CN944B85, CN959, CN961E75, CN961H81, CN962, CN963A80, CN963B80, CN963E75, CN963E80, CN963J75, CN964, CN964A85, CN964E75, CN965, CN965A80, CN966A80, CN966B85, CN966H90, CN966J75, CN966R60, CN968, CN980, CN981, CN981A75, CN981B88, CN982A75, CN982B88, CN982E75, CN982P90, CN983, CN985B88, CN989, CN991, CN996, CN9001, CN9002, CN9004, CN9005, CN9006, CN9007 CN9009, CN9010, CN9011, CN9014, CN9178, CN9788, CN9893 (manufactured by Sartomer Co., Ltd.),
U-4HA, U-6HA, U-6LPA, UA-1100H, UA-53H, UA-33H, U-200PA, UA-4200, UA-122P (manufactured by Shin-Nakamura Chemical Co., Ltd.),
New Frontier R-1214, New Frontier R-1301, New Frontier R-1304, New Frontier R-1306X, New Frontier R-1150D (Daiichi Kogyo Seiyaku Co., Ltd.),
EBECRYL230, EBECRYL244, EBECRYL245, EBECRYL264, EBECRYL265, EBECRYL270, EBECRYL284, EBECRYL285, EBECRYL294, EBECRYL1290, EBECRYL1290, EBECRYL1290, EBECRYL1290, EBECRYL1290, EBECRYL1290
UV-1700B, UV-7600B, UV-7605B, UV-6630B, UV-7000B, UV-7461TE, UV-3000B, UV-3310B, UV-3520TL, UV-3700B (manufactured by Nippon Synthetic Chemical),
Art Resin UN-333, UN-1255, UN-2600, UN-2700, UN-5500, UN-5507, UN-6060P, UN-6200, UN-6300, UN-6301, UN-7600, UN-7700, UN-9000PEP, UN-9200A, UN-3320HA, UN-3320HC, UN-904 (manufactured by Negami Kogyo Co., Ltd.)

  In the ink set of the present invention, the color ink, clear ink and white ink preferably contain a photopolymerization initiator. A photoinitiator has the effect | action which starts superposition | polymerization of the radical polymerizable monomer and acrylate oligomer which were mentioned above by irradiating an active energy ray. In addition, the content of the photopolymerization initiator is preferably 1 to 25% by mass in the ink, and more preferably 1 to 10% by mass. When the content of the photopolymerization initiator is less than 1% by mass, the printed layer may be poorly cured. When the content exceeds 25% by mass, precipitates are generated at low temperatures and ink ejection becomes unstable. There is. Furthermore, in order to accelerate the initiation reaction of the photopolymerization initiator, an auxiliary such as a photosensitizer can be used in combination.

  Examples of the photopolymerization initiator include benzophenone compounds, acetophenone compounds, thioxanthone compounds, phosphine oxide compounds, etc. From the viewpoint of curability, the wavelength of the active energy ray to be irradiated and the photopolymerization initiator It is preferable that the absorption wavelengths overlap as much as possible.

As a specific example of the photopolymerization initiator,
2,2-dimethoxy-1,2-diphenylethane-1-one,
1-hydroxy-cyclohexyl-phenyl-ketone,
2-hydroxy-2-methyl-1-phenylpropan-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,
Examples include 2-chlorothioxanthone. Among these, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is preferable from the viewpoint of curability of the printed layer. In addition, these photoinitiators may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the ink set of the present invention, the color ink, the clear ink, and the white ink may further contain a light stabilizer. The light stabilizer has an action of absorbing ultraviolet rays and preventing deterioration due to ultraviolet rays. Examples of the light stabilizer include cyanoacrylate compounds, benzophenone compounds, benzoate compounds, benzotriazole compounds, hydroxyphenyl triazine compounds, benzylidene camphor compounds, inorganic fine particles, etc. Among them, ultraviolet absorption has a shorter wavelength. The hydroxyphenyltriazine compound is preferably from the viewpoint of the curability of the ink. From the viewpoint of curability, it is preferable that the wavelength of the active energy ray to be irradiated and the absorption wavelength of the light stabilizer do not overlap as much as possible. In addition, the content of the light stabilizer is preferably 0.1 to 15% by mass in the ink, and more preferably 0.2 to 5% by mass. When the light stabilizer is blended in an amount of 0.1% by mass or more, weather resistance is improved because a sufficient ultraviolet ray absorbing effect is obtained, and when the content of the light stabilizer is 15% by mass or more, printing is performed. The curability of the layer is lowered and an excellent printed matter cannot be obtained.

As a specific example of the light stabilizer,
2,4-dihydroxybenzophenone,
2-hydroxy-4-methoxybenzophenone,
2-hydroxy-4-methoxybenzophenone-5-sulfonic acid,
2-hydroxy-4-octoxybenzophenone,
2-hydroxy-4-dodecyloxybenzophenone-2-hydroxy-4-benzyloxybenzophenone,
Bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane,
2,2′-dihydroxy-4-methoxybenzophenone,
2,2′-dihydroxy-4,4′-dimethoxybenzophenone,
2,2 ′, 4,4′-tetrahydroxybenzophenone,
2-hydroxy-4-methoxy-2′-carboxybenzophenone,
2- (2′-hydroxy-5′-methylphenyl) benzotriazole 2- [2′-hydroxy-3 ′, 5′-bis (α, α- (dimethylbenzyl) phenyl] benzotriazole,
2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole,
2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole,
2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole,
2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole,
2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole,
2,2′-methylene-bis [4- (1,1,3,3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol],
A condensate of methyl-3- [3-tert-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate and polyethylene glycol;
2- (2-hydroxyphenyl) benzotriazole,
2- (2′-hydroxy-5′-methylphenyl) benzotriazole,
2,6-di-tert-butylphenyl-3 ′, 5′-di-tert-butyl-4′-hydroxybenzoate,
And hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate. In addition, these light stabilizers may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the ink set of the present invention, the color ink and the white ink may further contain a pigment dispersant as necessary in order to disperse the pigment. In addition, content of a pigment dispersant is 0.1-5 mass% in an ink, for example. Moreover, a pigment dispersant may be used individually by 1 type, and may be used in combination of 2 or more type.

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 (above, manufactured by Big 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 (above, manufactured by Lubrizol),
Disparon DA-7301, Disparon DA-325,
Disparon DA-375, Disparon DA-234 (above, manufactured by Enomoto 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 (above, Kyoeisha Chemical Co.,
TEGO Dispers 610, TEGO Dispers 610S,
TEGO Dispers 630, TEGO Dispers 650,
TEGO Dispers 652, TEGO Dispers 655,
TEGO Dispers 662C, TEGO Dispers 670,
TEGO Dispers 685, TEGO Dispers 700,
TEGO Dispers 710, TEGO Dispers 740W,
LIPOTIN A, LIPOTIN BL,
LIPOTIN DB, LIPOTIN SB (above, manufactured by Evonik Degussa),
PB821, PB822, PN411, PA111 (above, manufactured by Ajinomoto Fine Techno Co.),
Texahole 963, Texahole 964, Texahole 987, Texahole P60, Texahole P61, Texahole P63, Texahole SF71, Texahole UV20, Texahole UV21 (above, manufactured by Cognis),
BorchiGen SN88, BorchiGen 0451 (above, manufactured by Bochas) and the like.

  In the ink set of the present invention, the color ink, the clear ink, and the white ink include, as other components, a polymerization inhibitor, an antioxidant, a silane coupling agent, a plasticizer, a rust inhibitor, a solvent, and a non-reactive polymer. Additives such as fillers, pH adjusters, antifoaming agents, charge control agents, stress relaxation agents, penetrating agents, light guide materials, bright materials, magnetic materials, and phosphors may be used as necessary.

  In the ink set of the present invention, the color ink, the clear ink, and the white ink are mixed with various components appropriately selected as necessary, and if necessary, about 1/10 of the nozzle diameter of the ink jet print head to be used. It can be prepared by filtering the resulting mixture using a filter with the following pore size. In the ink set of the present invention, the mixing ratio of the radical polymerizable monomer used in the color ink is adjusted, or the mixing ratio of the radical polymerizable monomer and the acrylic surface conditioner used in the clear ink and the white ink is adjusted. The desired viscosity and surface tension can be achieved.

  In the ink set of the present invention, the color ink, clear ink, and white ink have a viscosity at 40 ° C. of preferably 5 to 15 mPa · s, and more preferably 5 to 10 mPa · s. If the viscosity of the ink at 40 ° C. is within the specified range, good ejection stability can be obtained. The ink viscosity can be measured using a B-type viscometer.

  In the ink set of the present invention, the surface tension of the color ink, the clear ink, and the white ink is not particularly limited as long as the above relation is satisfied. For example, the surface tension of each ink at 25 ° C. It is preferably 25 to 40 mN / m, more preferably 30 to 40 mN / m, and still more preferably 32 to 38 mN / m. If the surface tension of the ink at 25 ° C. is within the specified range, good ejection stability can be obtained. The surface tension of the ink can be measured by a plate method.

  The ink set of the present invention can be used for various ink jet printers. Examples of the ink jet printer include an ink jet printer that ejects an ink composition by a charge control method or a piezo method. The ink set of the present invention can be suitably applied particularly to a large-sized ink jet printer, specifically, an ink jet printer intended for printing on articles produced on an industrial line. In addition, a printing layer with favorable weather resistance can be formed by irradiating an active energy ray and hardening a printing layer after printing with an inkjet printer. Further, the wavelength of the active energy ray irradiated for curing the printed layer preferably overlaps with the absorption wavelength of the photopolymerization initiator. For the ink set of the present invention, the active energy ray is mainly used. It is preferable that a wavelength is 360-425 nm.

  Next, the manufacturing method of the printed matter of this invention is demonstrated in detail. The manufacturing method of the 1st printed matter of this invention is characterized by including the process of discharging ink to the base-material surface by an inkjet printer provided with the ink set of the above-mentioned this invention, and forming a printing layer. According to the first method for producing a printed matter of the present invention, it is possible to provide a printed matter that can express a high-definition image without reducing the adhesion of the printed layer to the substrate. The second printed matter production method of the present invention includes a step of applying an undercoat paint to the surface of a substrate to form an undercoat film, and an ink jet ink by the ink jet printer provided with the above-described ink set of the present invention. And a step of ejecting the film onto the film to form a printed layer. According to the second method for producing a printed matter of the present invention, it is possible to provide a printed matter that can express a high-definition image without reducing the adhesion of the printed layer to the undercoat coating film.

  In the first and second methods for producing printed matter of the present invention, various ink jet printers can be used as the ink jet printer as the printing means as described above. Moreover, as described above, it is preferable to cure the printed layer formed on the substrate or the undercoat film by irradiating with active energy rays. Specifically, a clear ink or a white ink is ejected onto a substrate or an undercoat film, and a first layer is formed by irradiating the ink with an active energy ray, and a color ink is ejected onto the first layer. It is preferable that a second layer is formed by irradiating the ink with active energy rays to produce a printed layer including the first layer and the second layer. Thereby, a high-definition image can be expressed by the second layer formed from the color ink without reducing the adhesion of the printed layer to the substrate or the undercoat coating film.

  In the first and second methods for producing printed matter of the present invention, the substrate is not particularly limited, but preferred are substrates used in industrial lines. Moreover, as a shape of a base material, there exist plate shape etc., for example. Furthermore, as the material of the base material, for example, plastics such as ABS resin, polycarbonate, polyvinyl chloride, polystyrene, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polypropylene (PP), metals such as stainless steel and aluminum , Wood and glass.

  In the second method for producing a printed matter of the present invention, the undercoat paint includes an organic solvent-based paint using an organic solvent as a main solvent, a water-based paint using water as a main solvent, a solventless paint, various enamels of a powder paint, Various conventionally known paints such as clear paints can be used. Examples of the resin that can be used for the undercoat paint include various synthetic resins such as acrylic resin, alkyd resin, polyester resin, polyurethane resin, epoxy resin, silicone resin, and fluororesin. In addition, these resin may be used individually by 1 type, and may be used in combination of 2 or more type. As a method for applying the undercoat paint, various conventionally used coating means such as air spray, airless spray, roll coater and flow coater can be used, but printing means using an ink jet printer may also be used.

  It is preferable that the manufacturing method of the 1st and 2nd printed matter of this invention further includes the process of apply | coating a top coating material on the said printing layer, and forming a top coating film so that this printing layer may be covered. By forming the top coat film, it is possible to improve the adhesion of the printed layer to the substrate or the undercoat film. Moreover, it becomes possible to provide effects, such as a weather resistance and an abrasion resistance, with respect to printed matter by formation of a top coat film. For example, when the entire surface of the base material or undercoat film is coated with the printing layer, the topcoat film is formed only on the surface of the printing layer, but part of the base material or undercoat film is exposed. In some cases, the top coat film may be formed only on the surface of the print layer, or may be formed on the surface of the print layer and the exposed base material or surface of the undercoat film.

  In the first and second methods for producing printed matter of the present invention, the top coating material includes an organic solvent-based paint using an organic solvent as a main solvent, a water-based paint using water as a main solvent, a solvent-free paint, and a powder paint. Various conventionally known paints such as various enamels or clear paints can be used. Examples of the resin that can be used for the top coat include various synthetic resins such as acrylic resin, alkyd resin, polyester resin, polyurethane resin, epoxy resin, silicone resin, and fluororesin. In addition, these resin may be used individually by 1 type, and may be used in combination of 2 or more type. As a method for applying the top coating material, various conventionally used coating means such as air spray, airless spray, roll coater and flow coater can be used, but printing means using an ink jet printer may also be used.

  Next, the printed matter of the present invention will be described in detail. The printed matter of the present invention is obtained by the above-described printing method, and includes a base material and a printing layer, and may include an undercoat film between the base material and the printing layer, and further includes a printing layer. It is preferable to provide a top coat film so as to cover. According to the printed matter of the present invention, a high-definition image can be expressed without reducing the adhesion of the printed layer.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

(Example of preparation of surface conditioner 1)
In a polymerization apparatus equipped with a reflux condenser, a thermometer, a stirrer, and a dripping tank, 25 parts by mass of xylene are placed, and in a nitrogen atmosphere, the mixture solution according to the following formulation is kept at 110 ° C. and uniform over about 3 hours. The solution was dropped to obtain a copolymer (surface conditioning agent 1).
Butyl acrylate: 49 parts by mass 2-ethylhexyl acrylate: 20.9 parts by mass Acrylic acid: 0.1 parts by mass
(2-Ethylhexanoyl) (tert-butyl) peroxide [polymerization initiator]: 0.8 parts by mass

  This copolymer was obtained by a gel permeation chromatography (GPC) analyzer equipped with a TSKgel column (manufactured by Tosoh Corporation) (manufactured by Tosoh Corporation equipped with RI; HLC-8220GPC). As a result of analyzing the molecular weight distribution, the weight average molecular weight in terms of polystyrene was about 19000. The GPC conditions were that the developing solvent was tetrahydrofuran, the flow rate was 0.35 ml / min, and the temperature was 40 ° C. Further, the surface conditioning agent 1 had an SP value of 9.5 and a Tg of −64 ° C.

(Example of preparation of surface conditioner 2)
Except having used the mixture solution according to the following compounding prescriptions, it superposed | polymerized like the preparation example of the surface conditioning agent 1, and obtained the copolymer (surface conditioning agent 2). In addition, the surface conditioning agent 2 had a polystyrene equivalent weight average molecular weight of 6,000, an SP value of 9.5, and a Tg of −64 ° C.
Butyl acrylate: 49.0 parts by mass 2-ethylhexyl acrylate: 20.9 parts by mass Acrylic acid: 0.1 parts by mass
(2-Ethylhexanoyl) (tert-butyl) peroxide [polymerization initiator]: 0.4 parts by mass

(Example of preparation of surface conditioner 3)
Except having used the mixture solution according to the following compounding prescriptions, it superposed | polymerized like the preparation example of the surface conditioning agent 1, and obtained the copolymer (surface conditioning agent 3). In addition, the surface conditioning agent 3 had a polystyrene equivalent weight average molecular weight of 110,000, an SP value of 8.9, and a Tg of −64 ° C.
Butyl acrylate: 49.0 parts by mass 2-ethylhexyl acrylate: 20.9 parts by mass Acrylic acid: 0.1 parts by mass
(2-Ethylhexanoyl) (tert-butyl) peroxide [polymerization initiator]: 0.2 parts by mass

(Example of preparation of surface conditioner 4)
Except having used the mixture solution according to the following compounding prescriptions, it superposed | polymerized like the preparation example of the surface conditioning agent 1, and obtained the copolymer (surface conditioning agent 4). The surface conditioning agent 4 had a polystyrene equivalent of 20,000, an SP value of 10.6, and a Tg of −44 ° C.
Butyl acrylate: 49.0 parts by mass Hydroxyethyl acrylate: 20.9 parts by mass Acrylic acid: 0.1 parts by mass
(2-Ethylhexanoyl) (tert-butyl) peroxide [polymerization initiator]: 0.8 parts by mass

<Ink preparation method>
A mixture according to the formulation shown in Table 1 was obtained, and kneaded with a bead mill to make it homogeneous, and four color inks of cyan, magenta, yellow and black were prepared.

a) Disperbyk-168; manufactured by Big Chemie Japan, pigment dispersant b) Darocur TPO; manufactured by BASF, photopolymerization initiator, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

  About clear ink, the mixture according to the mixing | blending prescription shown in Tables 2-3 was prepared, and this was made into clear ink. Moreover, about white ink, the mixture according to the mixing | blending prescription shown in Tables 2-3 was knead | mixed with the bead mill, and it homogenized, and prepared white ink.

a) Disperbyk-168; manufactured by Big Chemie Japan, pigment dispersant b) Darocur TPO; manufactured by BASF, photopolymerization initiator, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide c) KF6020; Shin-Etsu Silicone Made of silicone surface conditioner

  Next, with respect to the color ink, the clear ink, and the white ink, the viscosity and the surface tension were measured by the following method to evaluate the ejection stability. The results for color ink are shown in Table 1, and the results for clear ink and white ink are shown in Tables 2-3.

<Viscosity measurement method>
The viscosity of the ink at 40 ° C. was measured using a B-type viscometer.

<Surface tension measurement method>
The surface tension of the ink at 25 ° C. was measured by the plate method.

<Evaluation of ejection stability>
Ink was ejected onto the substrate by an inkjet printer to print an image, and the ejection stability was visually evaluated according to the following criteria.
○: An image can be printed at a predetermined position without causing nozzle clogging.
Δ: No nozzle clogging occurs, but slight flight bending occurs.
X: Nozzle clogging occurs, the image is missing, and the ink cannot adhere to a predetermined position, so that a beautiful image cannot be printed.

  Next, an ink set was prepared by combining the four color inks shown in Table 1 and the clear ink or white ink shown in Tables 2 to 3, and the adhesion of the printed layer and the fineness of the image were performed by the following methods. Was evaluated. The results are shown in Tables 2-3. The ink set is composed of cyan ink, magenta ink, yellow ink, black ink, and white ink, or composed of cyan ink, magenta ink, yellow ink, black ink, and clear ink.

<Evaluation of adhesion>
A clear ink or white ink is ejected onto a plate-like base material of the material described in Table 2 or Table 3 by an inkjet printer including an ink set to form a first layer covering the entire surface of the base material, Subsequently, the first layer was cured by irradiating active energy rays having a main wavelength of 380 to 390 nm using an LED lamp (integrated light amount: 300 mJ / cm ² ).
Subsequently, color ink is ejected onto the first layer to print an image (second layer) of four color bars made up of cyan, magenta, yellow, and black, and then using an LED lamp, a main wavelength of 380 to 380 is printed. The image was cured by irradiating an active energy ray of 390 nm (integrated light amount: 300 mJ / cm ² ).
Next, a cross cut of 1 mm width and 100 mass was applied to the printed layer composed of the first layer and the second layer, and a cellophane tape was firmly attached to the cut portion. Thereafter, the cellophane tape was peeled off, and the adhesion of the printed layer was evaluated according to the following criteria.
◯: No peeling is confirmed at the cut part.
(Triangle | delta): Partial peeling can be confirmed in a cut part.
X: The entire cut part can be peeled off.

<Evaluation of image definition>
A first layer covering the entire surface of the substrate is printed by ejecting clear ink or white ink onto a plate-like substrate of the material described in Table 2 or Table 3 by an inkjet printer including the ink set, Subsequently, the first layer was cured by irradiating active energy rays having a main wavelength of 380 to 390 nm using an LED lamp (integrated light amount: 300 mJ / cm ² ).
Subsequently, color ink is ejected onto the first layer to print an image (second layer) of four color bars made up of cyan, magenta, yellow, and black, and then using an LED lamp, a main wavelength of 380 to 380 is printed. The image was cured by irradiating an active energy ray of 390 nm (integrated light amount: 300 mJ / cm ² ).
Next, the image was observed using a magnifying glass, and the dot shape of the color ink forming the image was evaluated according to the following criteria.
○: Adjacent dots do not merge but exist independently.
Δ: Some of the adjacent dots are united.
X: Many adjacent dots are united.

Next, using the ink set of Example 1, printed materials (Examples 14 to 19) obtained from the materials shown in Table 4 were produced. Specifically, for Examples 14, 15, 17 and 18, the undercoat paint described in the table was applied on the plate-like substrate of the material described in the table to form an undercoat film, Printing was performed on the primer coating. About Example 16 and 19, it printed on the plate-shaped base material of the material described in a table | surface. For the production of the printing layer, first, white ink is ejected onto the substrate or the undercoat film by an inkjet printer equipped with an ink set to form a first layer covering the entire surface of the substrate, and then the LED lamp is turned on. The first layer was cured by irradiating active energy rays having a main wavelength of 380 to 390 nm (integrated light amount: 300 mJ / cm ² ). Subsequently, color ink is ejected onto the first layer to print an image (second layer) of four color bars made up of cyan, magenta, yellow, and black, and then using an LED lamp, a main wavelength of 380 to 380 is printed. The image was cured by irradiating an active energy ray of 390 nm (integrated light amount: 300 mJ / cm ² ) to obtain a printed layer. For Examples 15, 16, 18 and 19, the top coating composition described in the table was applied onto the printing layer, and a top coating film was formed so as to cover the printing layer.

  The printed materials of Examples 14 to 19 were evaluated for adhesion of printed layers and image fineness by the following methods. The results are shown in Table 4.

<Evaluation of adhesion>
For Examples 14 and 17, the printed layer was subjected to a cross cut of 1 mm width and 100 mass, cellophane tape was firmly attached to the cut portion, and then the cellophane tape was peeled off.
For Examples 15, 16, 18, and 19, a 1 mm wide 100-mass cross cut was applied from the top coating film, and the cellophane tape was firmly attached to the cut portion, and then the cellophane tape was peeled off.
The adhesion of the printed layer was evaluated according to the following criteria.
◯: No peeling is confirmed at the cut part.
(Triangle | delta): Partial peeling can be confirmed in a cut part.
X: The entire cut part can be peeled off.

<Evaluation of image definition>
The image was observed using a loupe, and the dot shape of the color ink forming the image was evaluated according to the following criteria. In Examples 15, 16, 18 and 19, images were observed from above the top coat film.
○: Adjacent dots do not merge but exist independently.
Δ: Some of the adjacent dots are united.
X: Many adjacent dots are united.

Paint A: Acrylic paint "PP Coat Primer" (Dainippon Paint Co., Ltd.)
Paint B: Polyester melamine paint “PE Primer” (Dainippon Paint)
Paint C: Acrylic urethane paint “Acrytan SSCM-200” (Dainippon Paint)
Paint D: Polyester melamine paint “V Chroma # 100CW” (Dainippon Paint)

Claims (8)

An ink set comprising a combination of one or more color inks and a clear ink or white ink,
The color ink, clear ink and white ink are active energy ray-curable inkjet inks,
The color ink contains at least a colorant other than a white colorant, and does not contain a surface conditioner ,
The white ink contains at least a white colorant and an acrylic surface conditioner,
The clear ink contains at least an acrylic surface conditioner,
When the color ink is composed of one type, the surface tension of the clear ink and the white ink is higher than the surface tension of the color ink,
When the color ink is composed of a plurality of inks, the clear ink and the white ink have a surface tension higher than that of the color ink having the lowest surface tension among the color inks.   The acrylic surface conditioner is a polymer containing at least one acrylate monomer selected from the group consisting of lauryl (meth) acrylate, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate as a constituent unit. The ink set according to claim 1. The color-in click, the viscosity of the ink at 40 ° C. is 5 to 15 MPa · s, and 25 the surface tension of the ink at ° C. is according to claim 1 or 2, characterized in that a 25 to 40 mN / m Ink set. A first layer formed from the clear ink or white ink, for forming a printing layer and a second layer formed from the color ink on the first layer on any of claims 1-3 The ink set according to item 1. Claim 1 by an ink jet printer comprising the ink set according to any one of 4 clear ink or white ink is ejected to the substrate surface, a method of manufacturing a printed matter characterized in that it comprises a step of forming a printed layer . Applying an undercoat paint to the surface of the substrate to form an undercoat paint film, and discharging ink onto the undercoat paint film by an inkjet printer comprising the ink set according to any one of claims 1 to 4 . And a process for forming a printed layer. The method for producing a printed matter according to claim 5 or 6 , further comprising a step of applying a top coat onto the print layer and forming a top coat film so as to cover the print layer. A printed matter obtained by the method for producing a printed matter according to any one of claims 5 to 7 .