JP2010070754A - Energy ray-curable inkjet ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy ray-curable inkjet ink composition which is suitably used for such an application that a printed film is stretched together with a base material after printing of a marking film or a three-dimensional cubic display member. <P>SOLUTION: The energy ray-curable inkjet ink composition includes at least: a colorant; a reactive amide compound (A) having an ethylenic double bond; a bifunctional oligomer (B) which exhibits an elongation of ≥130% when it is polymerized and has two ethylenic double bonds in one molecule; at least one kind of photopolymerization initiator (C) selected from the group comprising acylphosphine oxide-based initiators (C-1) and α-aminoalkylphenone-based initiators (C-2); and a surface tension adjusting agent (D). In the composition, the content of the reactive amide compound (A) is 10-50 mass% and the content of the bifunctional oligomer (B) is 10-50 mass%, each based on the whole ink composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an energy ray curable inkjet ink composition. In particular, the present invention relates to a marking film used for decoration of a vehicle having a three-dimensional shape such as unevenness or a curved surface, a ship, a signboard, a wall surface of a building, or a three-dimensional three-dimensional display member on which a printed matter is three-dimensionally formed after printing. The present invention relates to an inkjet ink composition suitable for applications in which stretchability is required for a printed film after curing.

  A marking film, for example, a car wrapping film used for decoration of a vehicle or the like, generally forms a decorative print film with ink on one side of a polymer substrate made of a vinyl chloride resin sheet or the like, and adheres to the other side. It is produced by laminating release sheets via layers. Such a marking film can be directly attached to an object to be decorated such as a vehicle, and is excellent in workability. Therefore, the marking film is becoming popular as an alternative to the conventional marking method by painting. Further, for example, a three-dimensional display member such as an electric signboard is manufactured by printing a printed film made of various characters and images on a base material and then three-dimensionally forming a printed matter with a molding machine.

  In the marking film application as described above, when the marking film is applied to the object to be decorated, the release sheet is peeled off and the adhesive layer is attached to the surface of the object to be decorated. Since the surface is a three-dimensional shape such as an uneven surface or a curved surface, wrinkles are generated in the marking film, or air is likely to enter between the marking film and the object to be decorated, resulting in poor appearance. For this reason, it is necessary to affix a marking film on the surface of a to-be-decorated body, and a printing film | membrane may be extended | stretched for a fixed length with a base material in that case. Further, even in applications where a printed matter such as a three-dimensional stereoscopic display member is three-dimensionally formed, the printed film may be stretched together with the base material by bending at the time of forming. Therefore, in these applications, there is a demand for an ink that does not cause cracking or peeling even when the printing film is stretched (for example, 130% or more).

  In addition, in the formation of the printing film as described above, a plate making process is not required, and a printing method using an ink jet method suitable for a small amount of various types of variable printing is used. It is necessary to use an ink having liquid properties suitable for printing and excellent in continuous discharge properties. From the above viewpoint, in order to satisfy the stretchability of the printing film and the continuous ejection property in the ink jet system, a low-viscosity, stretchable water-based or solvent-based ink-jet ink using a dye or pigment as a coloring material is mainly used. It is used.

  However, water-based ink-jet inks have a problem that, when printed on a non-water-absorbing base material such as a polymer base material, the ink droplets are poorly attached, so that image formation is liable to occur. Since the drying is very slow, there is a problem that it is necessary to dry the marking film without overlapping immediately after printing. Further, since the marking film is assumed to be used outdoors, there is also a problem that water-based inkjet ink is inferior in water resistance. On the other hand, solvent-based ink-jet inks have excellent printability and water resistance on non-water-absorbing substrates such as polymer substrates, but it takes time to dry because it is necessary to dry the organic solvent. In addition, there is a problem that an exhaust facility and a solvent recovery mechanism for volatilizing the organic solvent must be provided.

  In addition to the above water-based and solvent-based ink-jet inks, solvent-free energy-ray-curable ink-jet inks that cure ink with energy rays such as ultraviolet rays have been developed as industrial ink-jet inks (for example, patents) Reference 1). This type of energy ray curable ink jet ink generates radicals by irradiation of energy rays and causes polymerization, so that the reaction is very fast and the curability is excellent. Moreover, since a solvent is not used, it has the advantage that it is excellent in the adhesiveness to a base material and quick-drying, and there is little environmental pollution. For this reason, in applications such as the marking film as described above, the energy beam curable inkjet ink may be used instead of the water-based or solvent-based inkjet ink. Since the print film is cured by the polymerization reaction of the polymerizable compound, it is necessary to use a polymerizable compound having as good curability as possible. Has been demanded. Therefore, a printing film formed using such an energy beam curable inkjet ink is basically not stretchable, and the printing film is easily cracked or peeled off by stretching.

  Studies have also been conducted to impart flexibility to printed films using energy ray curable ink jet inks, which contain reactive diluents and reactive oligomers as polymerizable compounds. An energy ray curable inkjet ink in which the glass transition temperature of the polymer and the polymer of the reactive oligomer alone is both −25 to 70 ° C. has also been proposed (for example, Patent Document 2).

  However, even in the energy ray curable inkjet ink as in Patent Document 2, in the application where the printing film is stretched 130% or more together with the base material after the marking film or the three-dimensional display member is cured, the printing film is cracked or peeled off. There is a problem that the occurrence of this cannot be suppressed. Moreover, in the above applications, solvent resistance against alcohol or the like is also required, but Patent Document 2 does not discuss such solvent resistance at all. Furthermore, in Patent Document 2, it is necessary to use a bifunctional polyfunctional monomer as a reactive diluent in order to form adhesiveness, scratch resistance, and a continuous printed film (see paragraph [0028 of Patent Document 2). ] To [0029]). For this reason, there exists a problem that hardening of a polymeric compound is accelerated | stimulated and a printing film tends to become hard. Furthermore, since these polyfunctional monomers have low dilutability, when used in combination with polyfunctional reactive oligomers, the ink tends to have high viscosity, and in the ink jet system, problems of ejection problems are likely to occur.

  In addition, low-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, xenon lamps, metal halide lamps, and the like have been used as means for curing the energy ray curable inkjet ink as described above. Then, since heat is likely to be generated, in applications such as a marking film in which a polymer base material is used, curling or waviness is likely to occur on the base material. For this reason, recently, it has been proposed to use a low-energy irradiation means such as an ultraviolet LED or an ultraviolet laser that is small and generates little heat instead of the mercury lamp or metal halide lamp as described above. However, the energy ray curable inkjet ink described in the above document has a problem that sufficient curability and adhesion cannot be obtained by such low energy irradiation means. In order to improve curability and adhesion, it may be possible to use a polyfunctional polymerizable compound having many ethylenic double bonds. In this case, however, the ink has a higher viscosity and the printed film becomes harder. Further, the stretchability is further lowered.

Japanese Patent No. 3619778

JP 2004-131725 A

  The present invention has been made to solve the above problems, and even when the energy ray curable inkjet ink is applied to an application in which the printing film is stretched together with the base material after printing such as a marking film or a three-dimensional stereoscopic display member. In addition, the printing film has excellent stretchability without cracking or peeling, and has excellent solvent resistance, and is excellent in curability and adhesion even when low energy irradiation means is used. It is an object of the present invention to provide an energy ray curable ink jet ink composition having excellent continuous discharge properties when printing with the ink.

The present invention is an energy beam curable inkjet ink composition capable of stretching a printed film after curing, the energy beam curable inkjet ink composition comprising:
When the coloring material, the reactive amide compound (A) having an ethylenic double bond, and the oligomer alone are polymerized, the polymer has an elongation of 130% or more at 25 ° C., and the ethylenic double in one molecule. At least one light selected from the group consisting of a bifunctional oligomer (B) having two bonds, an acylphosphine oxide initiator (C-1), and an α-aminoalkylphenone initiator (C-2). Containing at least a polymerization initiator (C) and a surface tension modifier (D);
The content of the reactive amide compound (A) is 10 to 50% by mass and the content of the bifunctional oligomer (B) is 10 to 50% by mass with respect to the entire ink composition.

  Since the ink composition contains a certain amount of the low-viscosity reactive amide compound (A), the low-viscosity ink composition suitable for the ink jet system even if it contains a large amount of the high-viscosity bifunctional oligomer (B). Can be prepared. Further, since the ink composition contains a certain amount of each of the reactive amide compound (A) having an ethylenic double bond and the bifunctional oligomer (B) having a high elongation rate, the ink composition is also cracked or peeled by stretching. It is possible to form a print film with little damage and improve the solvent resistance of the print film. And at least 1 sort (s) of photoinitiators (C) chosen from the group which consists of these polymeric compounds, an acylphosphine oxide type | system | group initiator (C-1), and an alpha-aminoalkyl phenone type | system | group initiator (C-2). ) Can be used to form a printed film having excellent curability and adhesion even when irradiated with low energy. Furthermore, since the ink composition contains a certain amount of each of the reactive amide compound (A) and the bifunctional oligomer (B) and the surface tension adjusting agent (D), it has a surface tension suitable for an ink jet system. Have.

  The photopolymerization initiator (C) preferably contains the α-aminoalkylphenone initiator (C-2) and further a thioxanthone initiator (C-3). If a mixed initiator in which an α-aminoalkylphenone initiator (C-2) and a thioxanthone initiator (C-3) are used in combination is used, a printed film having further excellent curability can be formed.

  The bifunctional oligomer (B) preferably has a weight average molecular weight of 800 to 8,000. Since the high molecular weight bifunctional oligomer has a large elongation, it is possible to obtain an ink composition having further excellent stretchability.

  The reactive amide compound (A) preferably contains at least one selected from the group consisting of an N-substituted (meth) acrylamide compound and an N-vinyl cyclic amide compound. The reactive amide compound has a large viscosity reduction effect and is excellent in reactivity, so that an ink composition having a low viscosity and excellent curability can be obtained even when added in a small amount.

  The surface tension modifier (D) preferably contains at least a silicone compound having a polydimethylsiloxane structure, and more preferably contains a silicone compound having an ethylenic double bond. The silicone-based compound has a large surface tension reducing effect and has reactivity, and thus can improve curability and adhesion.

  The ink composition may further contain 40% by mass or less of a monofunctional monomer (E) having one ethylenic double bond.

  The ink composition may further contain a hindered amine compound (F) having a 2,2,6,6-tetramethylpiperidinyl group as an anti-gelling agent. The ink composition is easily polymerized by heat and light during storage, so that the storage stability is likely to decrease.If the hindered amine compound is used, the storage stability is maintained and the curability is maintained. In addition, an ink composition having excellent adhesion can be obtained.

  As described above, according to the present invention, even in applications where the printing film is stretched together with the base material after printing such as a marking film or a three-dimensional stereoscopic display member, the printing film is excellently stretched without cracking or peeling. Energy-ray-curable inkjet with excellent solvent resistance, excellent curability and adhesion even when low energy irradiation means is used, and excellent continuous ejection when printing by inkjet method An ink composition can be provided.

  In the energy ray curable inkjet ink composition of the present embodiment, the reactive amide compound (A) having an ethylenic double bond is 10 to 50% by mass, preferably 15 to 45% by mass, based on the entire composition. contains. Since the ink composition of the present embodiment contains the reactive amide compound (A) having an ethylenic double bond, an ink composition having better curability than the case where a monofunctional (meth) acrylate monomer is used. In addition to being obtained, the viscosity of the resulting ink composition can be lowered even if a large amount of the high-viscosity bifunctional oligomer (B) is contained in order to impart stretchability.

  In the case where the content of the reactive amide compound (A) is less than 10% by mass, the curability is lowered or the bifunctional oligomer (B) is contained in a large amount in order to impart high stretchability to the printed film. In the ink composition, the viscosity increases, and it becomes difficult to adjust the viscosity to 40 mPa · s or less suitable for the ink jet system. On the other hand, when the content of the reactive amide compound (A) is more than 50% by mass, the content of the bifunctional oligomer (B) is decreased, and the curability is lowered or the stretchability is lowered.

  The reactive amide compound (A) is preferably at least one selected from the group consisting of N-substituted (meth) acrylamide compounds and N-vinyl cyclic amide compounds. Since these reactive amide compounds have a large viscosity reducing effect and are excellent in reactivity, an ink composition having an even lower viscosity and excellent curability can be obtained even when added in a small amount. Moreover, the number of the ethylenic double bonds in the molecule | numerator of the reactive amide compound (A) is although it does not specifically limit, 1-3 are preferable.

Specific examples of the reactive amide compound (A) include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N , N-dibutyl (meth) acrylamide, N, N-dihexyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-hexyl (meth) acrylamide , (Meth) acryloylmorpholine, N, N-dimethylaminomethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminohexyl (Meth) acrylamide, N, N-die Aminomethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-diethylaminohexyl (meth) acrylamide, N, N′-methylenebis (meth) acrylamide N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, Nn-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide, tertiary butyl (meth) acrylamide sulfonic acid, tarsha Libutyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-butoxymethyl (meth) Acrylamide, N- isobutoxymethyl (meth) acrylamide, N- ethoxymethyl (meth) acrylamide, N- vinylpyrrolidone, 5-methyl-N- vinylpyrrolidone, N- vinylcaprolactam, and N- vinyl formamide. These may be used alone or in combination. Among these, at least one selected from the group consisting of N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-vinylcaprolactam is preferable.

  The ink composition of the present embodiment has an elongation of 130% or more, preferably 160% or more at 25 ° C. when polymerizing a single oligomer, and has two ethylenic double bonds in one molecule. The bifunctional oligomer (B) having 10 to 50% by mass, preferably 15 to 45% by mass, based on the entire composition. Since the ink composition of the present embodiment contains a certain amount of the low-viscosity reactive amide compound (A), even if it contains a large amount of the bifunctional oligomer (B) as described above, it has a low viscosity of 40 mPa · s or less. Ink compositions can be prepared. By using a large amount of such a bifunctional oligomer (B) having a high elongation rate, the curability can be improved, and even in applications where the printed film is stretched 130% or more together with the substrate after curing, The occurrence of peeling is suppressed, and a print film excellent in stretchability can be obtained, and the solvent resistance of the print film can be improved. If the elongation is less than 130%, it is not possible to form a print film having sufficient stretchability, and when the print film is stretched after curing, cracks and peeling are likely to occur, and the print film is easily damaged. . An oligomer with a high elongation rate is preferable because it has excellent stretchability and solvent resistance. However, since the options of the bifunctional oligomer (B) are narrowed, the elongation rate is preferably 200% or less. In the present specification, the elongation percentage is a value when a polymer of a single oligomer is measured by a measurement method described later.

  In addition, the above bifunctional oligomer (B) has two ethylenic double bonds in one molecule in order to achieve both low viscosity of the ink composition and curability and adhesion. When the number of ethylenic double bonds in a molecule is one as an oligomer, that is, only a monofunctional oligomer is used, the reactivity is lowered, and the curability and adhesion are liable to be lowered by irradiation with low energy. On the other hand, when the number of ethylenic double bonds in one molecule is 3 or more as an oligomer, that is, when only a higher polyfunctional oligomer is used, the reactivity is improved, but the stretchability is lowered or the viscosity is increased. Continuous discharge performance decreases.

  If the content of the above bifunctional oligomer (B) is less than 10% by mass, the curability will be lowered by the low energy irradiation means, and the stretchability of the resulting printed film will be lowered, causing cracks and peeling. It's easy to do. On the other hand, when the content of the bifunctional oligomer (B) is more than 50% by mass, even if the reactive amide compound (A) is used, the effect of reducing the viscosity cannot be caught up, the ink composition is thickened, and the continuous ejection property is increased. Decreases.

  Moreover, as for the weight average molecular weight of said bifunctional oligomer (B), 800-8,000 are preferable. The stretchability can be further improved by using the high molecular weight bifunctional oligomer (B). In addition, in this specification, a weight average molecular weight is a value when an oligomer simple substance is measured with the measuring method mentioned later. The bifunctional oligomer (B) is preferably an aliphatic oligomer. An aliphatic oligomer has a larger elongation due to its molecular structure than an aromatic oligomer, and can form a printing film excellent in stretchability.

  Specifically as said bifunctional oligomer (B), a urethane acrylate oligomer, a polyester acrylate oligomer, an epoxy acrylate oligomer etc. are mentioned, for example. Among these, urethane acrylate oligomer is preferable. Examples of the bifunctional oligomer (B) available on the market include EBECRYL210, EBECRYL230, EBECRYL270, EBECRYL284, EBECRYL264, EBECRYL265, EBECRYL8402, EBECRYL8004, EBECRYL8804, EBECRYL8804, and EBECRYL80804. CN131B, CN964, CN980, CN981, CN982, CN991, CN996, CN9001, CN9002, CN9004, CN9007, CN9009, CN9014, CN9178, CN9873, CN971, CN973, CN2256, and the like. These may be used alone or in combination.

  If the ink composition of the present embodiment contains the reactive amide compound (A) and the bifunctional oligomer (B) in the above range, a monofunctional monomer having one ethylenic double bond in one molecule. (E) You may contain further. If a small amount of the monofunctional monomer (E) is contained, an ink composition having excellent curability and adhesion can be obtained without reducing stretchability. However, when a large amount of the monofunctional monomer (E) is added, the curability is lowered, or the printed film has high hardness and the stretchability is lowered. Therefore, the content of the monofunctional monomer (E) is 40% by mass or less. It is preferably 37% by mass or less, and more preferably 17% by mass or less.

  Specific examples of the monofunctional monomer (E) include amyl (meth) acrylate, isoamyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, isodecyl ( (Meth) acrylate, lauryl (meth) acrylate, isomyristyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tridecyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2- (meth) acryloyloxy Ethyl hexahydrophthalic acid, neopentyl glycol (meth) acrylic acid benzoate, butoxyethyl (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, methoxy-triethylene glycol (Meth) acrylate, methoxy-polyethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate, nonylphenol ethylene oxide adduct (meth) acrylate, tetrahydrofur Furyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) Acrylate, 2- (meth) acryloyloxyethyl-succinic acid, 2- (meth) acryloyloxyethyl-phthalic acid, 2- (meth) acryloyloxy Ethyl-2-hydroxyethyl - and phthalic acid. These may be used alone or in combination. The monomer may be substituted with a functional group such as phosphorus or fluorine. Among these, isooctyl (meth) acrylate and phenoxyethyl (meth) acrylate are particularly preferable because of their low viscosity.

  Furthermore, if the ink composition of the present embodiment contains the reactive amide compound (A) and the bifunctional oligomer (B) in the above range, 2 having two ethylenic double bonds in one molecule. A functional monomer may be contained. However, when the bifunctional monomer is added in a large amount, the continuous ejection property is lowered, and the adhesion and stretchability are lowered. Therefore, the content of the bifunctional monomer is preferably 10% by mass or less. Specifically as said bifunctional monomer, tetraethylenelene glycol diacrylate etc. are mentioned, for example.

  The ink composition of the present embodiment comprises an acyl phosphine oxide initiator (C-1) and an α-aminoalkylphenone initiator (C-2) in order to initiate polymerization by low energy irradiation means. It contains at least one photopolymerization initiator (C) selected from the group consisting of By using such a photopolymerization initiator, the curability and adhesion of the polymerizable compound containing the reactive amide compound (A) and the bifunctional oligomer (B) can be improved. Further, when the α-aminoalkylphenone initiator (C-2) is used, it is preferable to use the initiator in combination with the thioxanthone initiator (C-3). If it is a mixed initiator in which the α-aminoalkylphenone-based initiator (C-2) and the thioxanthone-based initiator (C-3) are used in combination, the curability and adhesion can be further improved.

  Specific examples of the acylphosphine oxide initiator (C-1) include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, and 2,6-dichlorobenzoyldiphenyl. Phosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, 2,6-dimethylbenzoyldiphenylphosphine oxide, 4-methylbenzoyldiphenylphosphine oxide, 4-ethylbenzoyldiphenylphosphine oxide, 4-isopropylbenzoyldiphenylphosphine Oxide, 1-methylcyclohexanoylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenyl Sphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2,4,6-trimethylbenzoylphenylphosphinic acid isopropyl ester, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine Examples include oxides. These may be used alone or in combination. Examples of the acylphosphine oxide initiator (C-1) available on the market include DAROCURE TPO manufactured by Ciba.

  Specific examples of the α-aminoalkylphenone initiator (C-2) include 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl- Examples include 2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-methyl-1- [4- (methoxythio) -phenyl] -2-morpholinopropan-2-one. These may be used alone or in combination. Examples of the α-aminoalkylphenone-based initiator (C-2) available on the market include IRGACURE 369 and IRGACURE 907 manufactured by Ciba.

  Specific examples of the thioxanthone initiator (C-3) include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4- Examples include dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone. These may be used alone or in combination. Examples of commercially available thioxanthone initiators (C-3) include KAYACURE DETX-S manufactured by Nippon Kayaku Co., and Chivacure ITX manufactured by Double Bond Chemical.

  The content of the acylphosphine oxide initiator (C-1), α-aminoalkylphenone initiator (C-2), and thioxanthone initiator (C-3) in the ink composition is a reactive amide. Although depending on the content of the polymerizable compound such as the compound (A) or the bifunctional oligomer (B), the total amount is usually 5 to 15% by mass with respect to the whole composition. When these contents are less than 5% by mass, the curability and the adhesion are likely to be lowered by irradiation with low energy. On the other hand, when these contents exceed 15% by mass, unreacted components remain and the print quality tends to be impaired. In particular, 40 to 99% by mass of α-aminoalkylphenone initiator (C-2) and 1 to 60% by mass of thioxanthone initiator (C-3) are used in the total amount of the photopolymerization initiator (C). It is preferable. If a photopolymerization initiator (C) containing the α-aminoalkylphenone initiator (C-2) and the thioxanthone initiator (C-3) in the above range is used, the curability and adhesion are further excellent. Ink composition can be obtained.

  The ink composition may further contain a conventionally known initiator as a photopolymerization initiator in addition to the above initiator. Such photopolymerization initiators include aryl alkyl ketone initiators, oxime ketone initiators, acyl phosphonate initiators, thiobenzoic acid S-phenyl initiators, titanocene initiators, and aromatic ketone initiators. Agents, benzyl initiators, quinone derivative initiators, ketocoumarin initiators, and the like. However, since the reactivity decreases when the content of these initiators increases, the total amount is preferably 0.5 to 5% by mass with respect to the entire composition.

  The ink composition of the present embodiment contains a surface tension adjusting agent (D). Suitable surface tension modifier (D) includes a silicone compound having a polydimethylsiloxane structure. If the silicone compound is used as the surface tension adjusting agent (D), the liquid physical properties such as the surface tension of the ink composition can be adjusted to a range suitable for the ink jet system. Of the silicone compounds, silicone compounds having an ethylenic double bond in the molecule are preferred. Adhesion can be further improved by using the polymerizable compound and a silicone compound having an ethylenic double bond in the molecule.

  Specific examples of the silicone compound include BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-315, BYK-320, and BYK-322 manufactured by BYK Chemie. BYK-323, BYK-325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-344, BYK-370, BYK-375, BYK-377, BYK-UV3500, BYK-UV3510, BYK -UV3570; TEGO-Rad2100, TEGO-Rad2200N manufactured by Degussa, TEGO-Rad2250, TEGO-Rad2300, TEGO-Rad2500, TEGO-Rad2600, TEGO-Rad2700; Granol 100, granol manufactured by Kyoeisha Chemical Co., Ltd. 15, Granol 400, Granol 410, Granol 435, Granol 440, Granol 450, B-1484, and the like Polyflow ATF-2, KL-600, UCR-L72, UCR-L93. These may be used alone or in combination. Among these, BYK-UV3500, BYK-UV3510, BYK-UV3570 manufactured by BYK-Chemie Corporation; TEGO-Rad2100, TEGO-Rad2200N, TEGO-Rad2250, TEGO-Rad2300, TEGO-Rad2600, TEGO-Rad2600, TEGO-Rad2600, manufactured by Degussa Rad2700; UCR-L72 and UCR-L93 manufactured by Kyoeisha Chemical Co. are preferred.

  The content of the surface tension adjusting agent (D) in the ink composition is preferably 2.5% by mass or less, and more preferably 0.02 to 2.5% by mass with respect to the entire composition. When there is more content of a surface tension regulator (D) than 2.5 mass%, an undissolved substance may arise or foaming may be caused.

  The ink composition may contain a conventionally known surface tension adjusting agent in addition to the silicone compound. Specific examples of such a surface tension adjusting agent include, for example, Emulgen manufactured by Kao Corporation.

  In the present embodiment, the ink composition may use conventionally known various dyes as the coloring material, but it is preferable to use either or both of an inorganic pigment and an organic pigment from the viewpoint of weather resistance. .

  Specific examples of the inorganic pigment include, for example, titanium oxide, zinc oxide, zinc oxide, tripone, iron oxide, aluminum oxide, silicon dioxide, kaolinite, montmorillonite, talc, barium sulfate, calcium carbonate, silica, alumina, cadmium. Red, Red, Molybdenum Red, Chrome Vermillion, Molybdate Orange, Yellow Lead, Chrome Yellow, Cadmium Yellow, Yellow Iron Oxide, Titanium Yellow, Chrome Oxide, Pyridian, Cobalt Green, Titanium Cobalt Green, Cobalt Chrome Green, Ultramarine Blue, Ultra Examples include marine blue, bitumen, cobalt blue, cerulean blue, manganese violet, cobalt violet, and mica.

  Specific examples of organic pigments include azo, azomethine, polyazo, phthalocyanine, quinacridone, anthraquinone, indigo, thioindigo, quinophthalone, benzimidazolone, and isoindoline organic pigments. Etc. Carbon black made of acidic, neutral or basic carbon may be used. Furthermore, a hollow particle of a crosslinked acrylic resin or the like may be used as the organic pigment.

  Specific examples of the pigment having a cyan color include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. And CI Pigment Blue 60. Among these, from the viewpoint of weather resistance and coloring power, C.I. I. Pigment blue 15: 3, C.I. I. Either or both of Pigment Blue 15: 4 are preferred.

  Specific examples of pigments having a magenta color include C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 168, C.I. I. Pigment red 184, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. Pigment red 254, C.I. I. Pigment violet 19 and the like. Among these, from the viewpoint of weather resistance and coloring power, C.I. I. Pigment red 122, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. Pigment red 254, and C.I. I. At least one selected from the group consisting of CI Pigment Violet 19 is preferred.

  Specific examples of the pigment having a yellow color include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14C, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 130, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 213, C.I. I. And CI Pigment Yellow 214. Among these, from the viewpoint of weather resistance, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. 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 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 213, and C.I. I. At least one selected from the group consisting of CI Pigment Yellow 214 is preferred.

  Specific examples of the pigment having a black color include, for example, HCF, MCF, RCF, LFF, SCF manufactured by Mitsubishi Chemical Corporation; Monarch, Legal manufactured by Cabot Corporation; Color Black, Special Black manufactured by Degussa Huls, Inc. Printex; Tokai Carbon manufactured by Tokai Carbon Co .; Raven manufactured by Columbia Co., etc. Among these, HCF # 2650, HCF # 2600, HCF # 2350, HCF # 2300, MCF # 1000, MCF # 980, MCF # 970, MCF # 960, MCF88, LFFMA7, MA8, MA11, MA77 manufactured by Mitsubishi Chemical Corporation MA100 and Degussa Huls, Printex 95, Printex 85, Printex 75, Printex 55, Printex 45, and at least one selected from the group consisting of Printex 45 are preferable.

  The content of the colorant in the ink composition is preferably 1 to 10% by mass, more preferably 2 to 7% by mass, and most preferably 3 to 6% by mass with respect to the entire composition. When the content of the coloring material is too small, the coloring power of the image tends to be reduced. On the other hand, when the content of the colorant is too large, the viscosity of the ink composition increases, and the fluidity tends to be impaired.

  When a pigment is used as the coloring material, a pigment derivative or a pigment dispersant may be further used in order to improve the dispersibility of the pigment. Specific examples of the pigment derivative include a pigment derivative having a dialkylaminoalkyl group and a pigment derivative having a dialkylaminoalkylsulfonic acid amide group. Specific examples of the pigment dispersant include ionic or nonionic surfactants and anionic, cationic or nonionic polymer compounds. Among these, a polymer compound containing a cationic group or an anionic group is preferable from the viewpoint of dispersion stability. Examples of commercially available pigment dispersants include SOLSPERS manufactured by Lubrizol, DISPERBYK manufactured by BYK Chemie, EFKA manufactured by Fuka Additives, and the like. The content of the pigment derivative and the pigment dispersant in the ink composition is preferably 0.05 to 5% by mass with respect to the entire composition.

  The ink composition of the present embodiment preferably further contains a hindered amine compound (F) having a 2,2,6,6-tetramethylpiperidinyl group. If the hindered amine compound (F) is contained together with the reactive amide compound (A), the bifunctional oligomer (B), and the photopolymerization initiator (C), the ink composition can be stored without lowering the curability. An ink composition having excellent stability can be obtained. Specific examples of the hindered amine compound (F) include bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate and decanedioic acid bis (2,2). , 6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) ester and the like. These may be used alone or in combination. Among these, bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate is preferable. Examples of the hindered amine compound (F) available in the market include IRGASTAB UV-10 and TINUVIN 123 manufactured by Ciba.

  The content of the hindered amine compound (F) in the ink composition is preferably 0.01 to 3% by mass and more preferably 0.2 to 2% by mass with respect to the entire composition. When the content of the hindered amine compound (F) is less than 0.01% by mass, radicals generated during storage cannot be sufficiently captured, and storage stability tends to decrease. On the other hand, when the content of the hindered amine compound (F) is more than 3% by mass, the radical scavenging effect is saturated and the polymerization reaction at the time of energy beam irradiation tends to be inhibited.

  The ink composition may further contain other hindered amine compounds, phenolic antioxidants, phosphorus antioxidants, hydroquinone monoalkyl ethers and the like as gelling inhibitors. Specific examples of such an anti-gelling agent include, for example, hydroquinone monomethyl ether, hydroquinone, t-butylcatechol, pyrogallol, TINUVIN 111 FDL, TINUVIN 144, TINUVIN 292, TINUVIN XP40, TINUVIN XP60, manufactured by Ciba. TINUVIN 400 etc. are mentioned. The total content of these anti-gelling agents in the ink composition is preferably 0.1 to 4% by mass relative to the entire composition.

  If necessary, the ink composition of the present embodiment further includes a surfactant, a leveling agent, an antifoaming agent, an antioxidant, a pH adjusting agent, a charge imparting agent, a bactericidal agent, an antiseptic, a deodorizing agent, and a charge adjusting agent. Well-known general additives such as wetting agents, anti-skinning agents, and perfumes may be added as optional components.

As a method for preparing the ink composition, conventionally known preparation methods can be used. However, when a pigment is used as the colorant, the following preparation method is preferable.
First, a mixture in which a colorant, a part of a polymerizable compound, and, if necessary, a pigment dispersant is premixed is prepared, and the mixture is dispersed by a disperser to prepare a primary dispersion. Specific examples of the disperser include a disperser; a container drive medium mill such as a ball mill, a centrifugal mill, and a planetary ball mill; a high-speed rotating mill such as a sand mill; and a medium agitation mill such as a stirring tank mill.

  Next, the remaining polymerizable compound, the photopolymerization initiator (C), the surface tension modifier (D), and, if necessary, other additives such as the hindered amine compound (F) are added to the primary dispersion. Add and mix uniformly using a stirrer. Specific examples of the stirrer include a three-one motor, a magnetic stirrer, a disperser, and a homogenizer. Further, the ink composition may be mixed using a mixer such as a line mixer. Furthermore, the ink composition may be mixed using a disperser such as a bead mill or a high-pressure jet mill for the purpose of further reducing the particles in the ink composition.

  When a pigment is used as the colorant, the dispersion average particle diameter of the pigment particles in the ink composition is preferably 20 to 200 nm, and more preferably 50 to 160 nm. If the dispersion average particle size is less than 20 nm, the particles are fine and the weather resistance of the printed matter tends to be lowered. On the other hand, when the dispersion average particle diameter exceeds 200 nm, the fineness of the printed matter tends to be lowered.

  According to the present embodiment, since the ink composition contains the reactive amide compound (A) and the bifunctional oligomer (B) having a high elongation rate, the amount of the ink composition is as low as 4 to 40 mPa · s at 25 ° C. Viscosity ink compositions can be prepared. Moreover, since the ink composition contains the polymerizable compound and the surface tension adjusting agent (D), an ink composition suitable for an ink jet system having a surface tension of 25 to 32 mN / m can be prepared. . For this reason, the ink composition of this Embodiment is excellent in continuous discharge property.

  In addition, the ink composition of the present embodiment does not need to contain a diluting solvent. However, for example, when an industrial product is used, the diluting solvent may be inevitably mixed into the ink composition. The amount of such a diluting solvent inevitably mixed is usually 3% by mass or less based on the total amount of the ink composition. In addition, the ink composition of the present embodiment has a low viscosity even without heating, and also has good pigment dispersibility when the colorant is a pigment, and the viscosity increases during storage and use. Or good dispersion stability without causing problems such as precipitation of pigments. For this reason, even if it does not use a dilution solvent substantially, in an inkjet system, stable discharge is obtained at room temperature, without heating ink.

  When producing a marking film such as a car wrapping film, for example, an ink composition is printed in a predetermined pattern by an inkjet method on one side of a base material made of a polymer resin such as vinyl chloride resin, polyethylene terephthalate, polycarbonate, A marking film can be produced by laminating an adhesive layer and a release sheet on the other side of the substrate. In the case of producing a three-dimensional stereoscopic display member for three-dimensionally forming a printed material, similarly, for example, after printing an ink composition in a predetermined pattern by an inkjet method on one surface side of a polymer substrate, the printed material is obtained in a desired pattern. A three-dimensional three-dimensional display member can be produced by three-dimensional molding into a shape.

  The inkjet method is not particularly limited, but is a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electrical signal. An acoustic ink jet method using a radiation pressure that irradiates the ink by changing the sound beam into an acoustic beam, and a thermal ink jet method using the pressure generated by heating the ink to form bubbles. The ink jet method includes a method of ejecting a large number of low-density inks called photo inks in a minute volume, a method of improving image quality using a plurality of inks having substantially the same hue and different densities, and colorless and transparent inks. The method using is included.

In the present embodiment, as the irradiation means, an ultraviolet LED, an ultraviolet laser, or the like can be used in addition to a mercury lamp or a metal halide lamp. In particular, ultraviolet LEDs and ultraviolet lasers have low energy and require high curing sensitivity, so that the above ink composition is effective. For example, in the case of the ink composition of the present embodiment, a low energy of 500 mJ / cm ² or less can be used as the cumulative amount of ultraviolet light. The energy rays are preferably irradiated to the ink composition after 1 to 1,000 ms elapses after the ink composition is discharged onto the substrate. If the elapsed time is less than 1 ms, the distance between the head and the light source is too short, and the head may be irradiated with energy rays, leading to an unexpected situation. On the other hand, when the elapsed time exceeds 1,000 ms, when multiple colors are used, the image quality tends to deteriorate due to ink bleeding.

  Hereinafter, the present invention will be described more specifically based on examples. The present invention is not limited to these examples. In the following, “part” means “part by mass”.

  The ink components used in each example and comparative example are shown in Table 1 below. The indications of ink compositions in Tables 2 to 4 indicate the same compositions as the indications in parentheses in the type column in Table 1. In addition, the elongation rate of the oligomer simple substance and the weight average molecular weight were measured by the following.

[Elongation rate of oligomer]
Oligomer and 1-hydroxycyclohexyl phenyl ketone (1,2-α-hydroxyalkylphenone initiator, manufactured by Ciba, IRGACURE 184) [mass ratio of oligomer / initiator: 97/3] as an initiator and a diluent solvent As a solution, methyl ethyl ketone was mixed so as to have a viscosity of 100 mPa · s (25 ° C.). This solution was applied onto a glass substrate using a bar coater so that the film thickness after drying was 50 to 100 μm to form a uniform coating film. Next, after drying the said glass substrate for 5 minutes in a 60 degreeC chamber, the ultraviolet-ray (integrated light quantity: 1,000mJ / cm < ² >) was irradiated to the coating film using the metal halide lamp, and the polymer was formed. The obtained polymer was peeled from the glass substrate and cut into a size of 50 mm length × 10 mm width to prepare a measurement sample. When this measurement sample was stretched at a pulling rate of 1 mm / s using a tensile tester (manufactured by Shimadzu Corp., Autograph AGS-H 100N) at 25 ° C., the elongation at break was determined as the elongation of the polymer alone. Rate.

[Weight average molecular weight of oligomer]
The oligomer simple substance was measured by gel permeation chromatography (GPC), and the weight average molecular weight in terms of polystyrene was determined (solvent: tetrahydrofuran).

[Preparation of ink]
In a 100 cc plastic bottle, the colorant, pigment dispersant, and isooctyl acrylate (IO-A) are weighed in the amounts shown in Tables 2 to 4, and 100 parts of zirconia beads are added thereto, and the mixture is then applied to the paint conditioner. (Toyo Seiki Co., Ltd.) was dispersed for 2 hours to obtain a primary dispersion. Next, the remaining components were added to the obtained primary dispersion in the amounts shown in Tables 2 to 4, and the mixture was stirred with a magnetic stirrer for 30 minutes. After stirring, the mixture was suction filtered using a glass filter (manufactured by Kiriyama Seisakusho) to prepare an ink. In Examples and Comparative Examples where IO-A was not used, a primary dispersion was prepared using a reactive amide compound instead of IO-A.

[Evaluation]
The following viscosity, dispersion average particle diameter, surface tension, and storage stability were measured for the inks of Examples and Comparative Examples prepared as described above.

〔viscosity〕
Using an R100 viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity was measured under the conditions of 25 ° C. and cone rotation speed of 20 rpm.

[Dispersion average particle diameter]
The dispersion average particle diameter of the pigment particles was measured using a particle size distribution measuring device FPER-1000 (manufactured by Otsuka Electronics Co., Ltd.).

〔surface tension〕
The surface tension at 25 ° C. was measured using a fully automatic balance type electro surface tension meter ESB-V (manufactured by Kyowa Kagaku).

[Storage stability]
The ink was filled into an aluminum pouch coated with polyethylene on the inside. After the container was stored at 70 ° C. for 14 days, the viscosity change of the ink and the presence or absence of gelation were observed, and the storage stability was evaluated according to the following criteria.
○: Viscosity change of less than 10% Δ: Viscosity change of 10% or more ×: Gelation progresses in the container, and the ink becomes solid.

  Next, the following ejection performance test was performed on each ink of the example and the comparative example, and the continuous ejection performance was evaluated.

[Continuous discharge]
Using an ink jet recording apparatus equipped with a piezo ink jet nozzle, a discharge property test was performed in which ink was continuously discharged for 30 minutes, and the continuous discharge property was evaluated according to the following criteria. The ink jet recording apparatus includes an ink tank, a supply pipe, a front chamber ink tank immediately before the head, and a piezo head as an ink supply system. Further, the ink jet recording apparatus was driven at a driving frequency of 28 KHz so that the ink could be ejected with a droplet size of about 6 pl and a resolution of 1200 × 1200 dpi.
○: No discharge failure occurs. Δ: No nozzle chipping occurs but satellites are generated. ×: Nozzle chipping occurs.

  Next, the following curability, adhesion, stretchability, and solvent resistance were evaluated for the print films printed using the inks of Examples and Comparative Examples.

[Curing property]
On each film made of polyvinyl chloride (PVC) and polyethylene terephthalate (PET), the ink was printed by a bar coater to form a printing film having a thickness of 3 μm (bar coater: # 6). The printed film was cured by irradiating with ultraviolet rays such that an ultraviolet LED (NCCU001E manufactured by Nichia Corporation) was used as an irradiating means, and the total irradiation light amount was 300 mJ / cm ² .
The printed film thus cured was touched with a finger, the presence or absence of ink adhering to the finger was visually examined, and the curability was evaluated according to the following criteria.
○: Ink does not adhere to the finger △: Ink does not adhere to the finger, but the printed film surface is scratched ×: Ink adheres to the finger

[Adhesion]
On each film made of polyvinyl chloride (PVC) and polycarbonate (PC), ink was printed by a bar coater to form a printing film having a thickness of 3 μm (bar coater: # 6). The printed film was cured by irradiating with ultraviolet rays such that an ultraviolet LED (NCCU001E manufactured by Nichia Corporation) was used as an irradiating means, and the total irradiation light amount was 300 mJ / cm ² .
The cross-cut test (1 mm square, 100 pieces) for confirming the peeled state with the cello tape (registered trademark) was performed on the printed film thus cured according to JIS-K-5400. The number of peels in 100 pieces was examined, and the adhesion was evaluated according to the following criteria.
○: The number of peels in the cross cut test is 10 or less Δ: The number of peels in the cross cut test is 11 to 20 ×: The number of peels in the cross cut test is 21 or more

[Extensible]
On a film made of polyvinyl chloride (PVC), ink was printed by a bar coater to form a printed film having a thickness of 3 μm (bar coater: # 6). The printed film was cured by irradiating with ultraviolet rays such that an ultraviolet LED (NCCU001E manufactured by Nichia Corporation) was used as an irradiating means, and the total irradiation light amount was 300 mJ / cm ² . After curing, a measurement sample was prepared by cutting the printed film into a 10 mm × 120 mm strip.
The position of 10 mm from one end in the long side direction of the measurement sample prepared as described above is fixed to the sample stage, and the position 10 mm from the other end is pulled by hand at a speed of 1 cm / s, and the printed film is cracked. Alternatively, the stretch length until peeling occurred was measured, and the stretchability was evaluated from the following criteria. The measurement environment temperature was room temperature.
○: The printed film is not cracked or peeled even when the measurement sample is stretched 150% or more. Δ: The printed film is cracked or peeled while the measurement sample is stretched 130% to 150%. The printed film cracks and peels while the film is stretched 120% to 130%. XX: The printed film cracks and peels before the measured sample is stretched 120%.

[Solvent resistance]
On a film made of polyvinyl chloride (PVC), ink was printed by a bar coater to form a printing film having a thickness of 3 μm (bar coater: # 6). The printed film was cured by irradiating with ultraviolet rays such that an ultraviolet LED (NCCU001E manufactured by Nichia Corporation) was used as an irradiating means, and the total irradiation light amount was 300 mJ / cm ² .
The printed film surface thus rubbed 10 times with a cotton swab containing ethanol was visually observed, and the solvent resistance was evaluated according to the following criteria.
◎: No change on the surface of the print film ○: A slight change is seen on the surface of the print film △: A part of the print film is peeled ×: More than half of the print film is peeled off

  Tables 5 to 7 show the above evaluation results.

  As shown in the above table, the inks of the examples have a viscosity of 27.6 to 39.7 mPa · s, a surface tension of 28.6 to 30.5 mN / m, a low viscosity, and an inkjet system. It can be seen that the surface tension is suitable for. For this reason, the ink of an Example is excellent in continuous discharge property. In particular, it can be seen that the inks of Examples 10, 12 and 13 have a low viscosity of 40 mPa · s or less despite containing 35 mass% or more of the bifunctional oligomer (B). In addition, it can be seen that the inks of the examples are excellent in curability, adhesion, and solvent resistance even when cured using a low-energy ultraviolet LED. In addition, it can be seen that the inks of the examples have excellent stretchability, and even when the print film is stretched 130% or more after curing, a print film with little cracking or peeling can be formed. Furthermore, it can be seen that the inks of the examples containing the hindered amine compound (F) having a 2,2,6,6-tetramethylpiperidinyl group as an anti-gelling agent have excellent storage stability.

  In contrast, an ink that does not contain a reactive amide compound (A) and contains only a monofunctional monomer and a bifunctional oligomer (B) as a monomer has a high viscosity and is not suitable for an ink jet system. I understand. Moreover, it turns out that this ink is inferior to sclerosis | hardenability and adhesiveness. Moreover, it turns out that the ink containing a polyfunctional monomer and not containing a bifunctional oligomer (B) has high viscosity and low stretchability. Furthermore, even if it contains the reactive amide compound (A), it can be seen that an ink containing only an oligomer having a low elongation as an oligomer is inferior in stretchability. Moreover, it turns out that the ink containing a monofunctional oligomer is inferior to sclerosis | hardenability.

  And even if it contains the reactive amide compound (A) and the bifunctional oligomer (B) having a high elongation rate, the ink having too little or too much content has high viscosity or is inferior in curability. I understand that. In addition, it can be seen that the ink not containing the surface tension adjusting agent (D) has a high surface tension and is not suitable for the ink jet system. In addition, since the printed film formed using the inks of Comparative Examples 4 and 6 had insufficient curability, the adhesion and stretchability could not be evaluated.

Claims (8)

An energy ray curable inkjet ink composition capable of stretching a printed film after curing,
A coloring material,
A reactive amide compound (A) having an ethylenic double bond;
A bifunctional oligomer (B) having an elongation of 130% or more at 25 ° C. when polymerizing a single oligomer, and having two ethylenic double bonds in one molecule;
At least one photopolymerization initiator (C) selected from the group consisting of an acylphosphine oxide initiator (C-1) and an α-aminoalkylphenone initiator (C-2);
Containing at least a surface tension adjusting agent (D),
An energy ray curable inkjet ink in which the content of the reactive amide compound (A) is 10 to 50% by mass and the content of the bifunctional oligomer (B) is 10 to 50% by mass with respect to the entire ink composition. Composition.   The energy beam curable inkjet according to claim 1, wherein the photopolymerization initiator (C) contains the α-aminoalkylphenone initiator (C-2) and a thioxanthone initiator (C-3). Ink composition.   The energy ray-curable inkjet ink composition according to claim 1 or 2, wherein the bifunctional oligomer (B) has a weight average molecular weight of 800 to 8,000.   The reactive amide compound (A) contains at least one selected from the group consisting of an N-substituted (meth) acrylamide compound and an N-vinyl cyclic amide compound. Energy ray curable inkjet ink composition.   The energy ray curable inkjet ink composition according to any one of claims 1 to 4, wherein the surface tension adjusting agent (D) contains at least a silicone compound having a polydimethylsiloxane structure.   The energy ray-curable inkjet ink composition according to claim 5, wherein the silicone compound has an ethylenic double bond in the molecule.   Furthermore, the monofunctional monomer (E) which has one ethylenic double bond is contained, and content of the said monofunctional monomer (E) is 40 mass% or less, The any one of Claims 1-6. Energy ray curable inkjet ink composition.   The energy ray curable inkjet ink composition according to any one of claims 1 to 7, further comprising a hindered amine compound (F) having a 2,2,6,6-tetramethylpiperidinyl group.