JP6791296B2 - Containment and Inkjet Method - Google Patents

Description

The present invention relates to UV curable inkjet compositions, inclusions and inkjet methods.

The inkjet recording method is a relatively simple device that can record high-definition images, and is rapidly developing in various fields. Among them, various studies have been made on ink compositions used in an inkjet recording method in which an ink is cured by irradiating it with ultraviolet rays. For example, Patent Document 1 provides an inkjet recording method that is inexpensive, suitable for printing, etc., and has excellent density change with time, bleeding, uneven penetration, bending resistance, cockling, rubbing resistance, and ejection property. intended, high ink absorbency paper moisture content is 5 mass% or less than 0% by weight and water content a converted per 1m ² (g / m ²⁾ is adjusted so as to satisfy specific conditions An inkjet recording method is described in which a system recording medium is recorded by using an ink having a surface tension of 20 mN / m or more and 35 mN / m or less and which is cured by a cationic polymerization reaction with active energy rays.

JP-A-2005-2005

The inkjet recording method as described in Patent Document 1 is intended to eliminate water in the ink as much as possible in order to achieve a predetermined purpose. In particular, since ink that is cured by a cationic polymerization reaction is used, we are trying to reduce the amount of water that has a large effect on curability as much as possible. However, when a polymerizable compound having a high curing rate is used, it is difficult to achieve both curability and storage stability at a high level.

The present invention has been made to solve at least a part of the above-mentioned problems, and includes an ultraviolet curable inkjet composition capable of achieving both curability and storage stability at a high level, and the composition thereof. It is an object of the present invention to provide an inkjet recording method using the container and the composition thereof.

The present inventors have diligently studied to solve the above problems. As a result, they have found that the above problems can be solved by using a specific polymerizable compound and keeping the water content in the ink composition within a predetermined range, and have completed the present invention.

That is, the present invention is as follows.
[1] Containing a polymerizable compound having a vinyl ether group and a (meth) acryloyl group, the water content is 0.05% by mass or more and 1.0% by mass or less based on the total amount of the composition. Is an ultraviolet curable inkjet composition.
[2] The inkjet composition according to [1], which is a radical polymerization type ultraviolet curable composition.
[3] The inkjet composition according to [1] or [2], which contains 3.0 to 15% by mass of an acylphosphine oxide-based photopolymerization initiator with respect to the total amount of the composition.
[4] The inkjet composition according to any one of [1] to [3], which contains the polymerizable compound in an amount of 10 to 70% by mass based on the total amount of the composition.
[5] As the polymerizable compound, the following general formula (1):
CH ₂ = CR ^1- COOR ^2- O-CH = CH-R ³ ... (1)
(In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. The inkjet composition according to any one of [1] to [4], which contains a polymerizable compound represented by ().
[6] The inkjet composition according to any one of [1] to [5], which further contains a monofunctional (meth) acrylate having an aromatic ring.
[7] An accommodating body containing the inkjet composition according to any one of [1] to [6].
[8] A container including the container and the composition according to any one of [1] to [6] filled in the container, and the water vapor permeability of the members constituting the container. There, 40 ° C., at 30g / m ² · 24hrs or less under a relative humidity of 90% for the accommodation body.
[9] A container comprising the container and the composition according to any one of [1] to [6] filled in the container, and a sealing member for storing and sealing at least the container. wherein the water vapor transmission rate of the sealing member is ^{40 ℃, 30g / m 2 ·} 24hrs or less under a relative humidity of 90% for the accommodation body.
[10] An inkjet method comprising an adhesion step of adhering the inkjet composition according to any one of [1] to [6] to an object to be ejected.
[11] The inkjet method according to [10], which comprises a curing step of irradiating the composition adhered to the ejected body with light by an ultraviolet light emitting diode having an emission peak wavelength in the range of 360 to 420 nm to cure the composition.

It is an exploded perspective view which shows an example of the containment body of this invention.

Hereinafter, a mode for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary, but the present invention is not limited thereto. Various modifications are possible without departing from the gist. In the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. Further, unless otherwise specified, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown. Further, in the present specification, "(meth) acrylic" means "acrylic" and its corresponding "methacrylic", and "(meth) acrylate" means "acrylate" and its corresponding "methacrylate". "(Meta) acryloyl" means "acryloyl" and its corresponding "methacrylic".

[Ultraviolet curable inkjet composition]
The ultraviolet curable inkjet composition of the present embodiment (hereinafter, also simply referred to as “composition”) is a composition used by being ejected by an inkjet method, and is a composition contained in an container, and is vinyl ether. It contains a polymerizable compound having a group and a (meth) acryloyl group, and water. The amount of water contained therein is 0.05% by mass or more and 1.0% by mass or less with respect to the total amount of the composition. The composition is preferably a radical polymerization type ultraviolet curable composition from the viewpoint of further enhancing its curability. Hereinafter, although it is also described as an “ink composition” used for recording as one embodiment of the composition, the composition may be a composition other than the ink composition.

Such an ink composition contains a polymerizable compound having a vinyl ether group and a (meth) acryloyl group, and the polymerizable compound proceeds rapidly in the polymerization reaction and is excellent in curability. On the other hand, when the ink composition usually contains such a polymerizable compound in which the polymerization reaction easily proceeds, the polymerizable compound slightly reacts during storage, resulting in a decrease in storage stability. However, the ink composition of the present embodiment has a water content of 0.05% by mass or more and 1.00% by mass or less, and the specific amount of water causes the reaction of the polymerizable compound during storage of the ink composition. Since it can be suppressed, the storage stability is also excellent. However, the factors that enable the ink composition of the present embodiment to have both curability and storage stability at a high level are not limited to these.

(Polymerizable compound)
The ink composition contains one or more polymerizable compounds having a vinyl ether group and a (meth) acryloyl group. Such a polymerizable compound can be polymerized alone or by the action of a polymerization initiator by applying energy such as light irradiation to cure the ink composition on the recording medium. The polymerizable compound is not particularly limited, but a (meth) acrylate having a vinyl ether group is preferable from the viewpoint of more effectively and surely solving the problems of the present invention. Examples of such a polymerizable compound include (meth) acrylates having a monofunctional or polyfunctional vinyl ether group, and these are preferable from the same viewpoints as described above.

The monofunctional (meth) acrylate having a vinyl ether group is not particularly limited, but from the viewpoint of lowering the viscosity of the ink composition, having a high flash point, and further enhancing the curability of the ink composition, the following general formula ( 1):
CH ₂ = CR ^1- COOR ^2- O-CH = CH-R ³ ... (1)
It is preferable to contain a polymerizable compound represented by. Here, in the formula (1), R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or 1 to 11 carbon atoms. It is a monovalent organic residue. Since the polymerizable compound represented by the general formula (1) further enhances the curability of the ink composition, it tends to reduce the storage stability. However, the composition of the ink composition of the present embodiment By providing the above, the decrease in storage stability can be suppressed more efficiently. As a result, when the ink composition of the present embodiment contains the polymerizable compound represented by the general formula (1), curability and storage stability can be achieved at a higher level.

Examples of the polymerizable compound represented by the general formula (1) include 2-vinyloxyethyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, and 1-methyl-2-vinyloxyethyl (meth) acrylate. , (Meta) 2-vinyloxypropyl acrylate, (meth) 4-vinyloxybutyl acrylate, 1-methyl-3-binyloxypropyl (meth) acrylate, 1-vinyloxymethylpropyl (meth) acrylate, (meth) ) 2-Methyl-3-vinyloxypropyl acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth) acrylate, 3-vinyloxybutyl (meth) acrylate, 1-methyl-2-vinyloxy (meth) acrylate Propyl, 2-vinyloxybutyl (meth) acrylate, 4-vinyloxycyclohexyl (meth) acrylate, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate, (meth) acrylic Acid 3-vinyloxymethylcyclohexylmethyl, (meth) acrylate 2-vinyloxymethylcyclohexylmethyl, (meth) acrylate p-vinyloxymethylphenylmethyl, (meth) acrylate m-vinyloxymethylphenylmethyl, (meth) ) O-vinyloxymethylphenylmethyl acrylate, 2- (vinyloxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxy) (meth) acrylate Ethoxy) propyl, 2- (vinyloxyethoxy) isopropyl (meth) acrylate, 2- (vinyloxyisopropoxy) propyl (meth) acrylate, 2- (vinyloxyisopropoxy) isopropyl (meth) acrylate, (meth) ) 2- (Vinyloxyethoxyethoxy) ethyl acrylate, 2- (vinyloxyethoxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyisopropoxyethoxy) ethyl (meth) acrylate, (meth) acrylic acid 2- (Vinyloxyisopropoxyisopropoxy) ethyl, (meth) acrylate 2- (vinyloxyethoxyethoxy) propyl, (meth) acrylate 2- (vinyloxyethoxyisopropoxy) propyl, (meth) acrylate 2- (Vinyloxyisopropoxyethoxy) propyl, (meth) acrylate 2- (vinyloxyisopropoxyisopropoxy) propyl, (meth) acrylate 2- (vinyloxyethoxyethoxy) isopropyl, 2- (Biniroxyethoxyisopropoxy) isopropyl (meth) acrylate, 2- (biniroxyisopropoxyethoxy) isopropyl (meth) acrylate, 2- (biniroxyisopropoxyisopropoxy) isopropyl (meth) acrylate, ( Examples thereof include 2- (biniroxyethoxyethoxyethoxy) ethyl (meth) acrylate and 2- (biniroxyethoxyethoxyethoxyethoxy) ethyl (meth) acrylate. These may be used alone or in combination of two or more.

Among these, from the same viewpoint as above, 2- (vinyloxyethoxy) ethyl (meth) acrylate, that is, 2- (vinyloxyethoxy) ethyl acrylate and 2- (vinyloxyethoxy) ethyl methacrylate Of these, at least one is preferable, and 2- (biniroxyethoxy) ethyl acrylate is more preferable. Since both 2- (vinyloxyethoxy) ethyl acrylate and 2- (vinyloxyethoxy) ethyl methacrylate have a simple structure and a small molecular weight, the viscosity of the ink composition can be significantly reduced. Examples of 2- (vinyloxyethoxy) ethyl (meth) acrylate include 2- (2-vinyloxyethoxy) ethyl (meth) acrylate and 2- (1-vinyloxyethoxy) ethyl (meth) acrylate. Examples of 2- (binyloxyethoxy) ethyl acrylate include 2- (2-vinyloxyethoxy) ethyl acrylate and 2- (1-vinyloxyethoxy) ethyl acrylate. In addition, 2- (vinyloxyethoxy) ethyl acrylate is superior to 2- (vinyloxyethoxy) ethyl methacrylate in terms of curability.

The content of the polymerizable compound having a vinyl ether group and a (meth) acryloyl group is preferably 10 to 70% by mass, more preferably 10 to 60% by mass, based on the total amount (100% by mass) of the ink composition. 10 to 50% by mass is more preferable. When the content is 10% by mass or more, the viscosity of the ink composition can be reduced, and the curability of the ink composition tends to be more excellent. On the other hand, when the content is 70% by mass or less, the ink composition tends to be more excellent in storage stability and the surface gloss of the printed matter.

The ink composition may contain one or more monofunctional, bifunctional, and trifunctional or higher polyfunctional monomers other than those exemplified above. Such monomers are not particularly limited, but are, for example, unsaturated carboxylic acids of (meth) acrylic acid, itaconic acid, crotonic acid, isocrotonic acid and maleic acid; salts of the unsaturated carboxylic acid; Esters, urethanes, amides and anhydrides; acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes.

The monofunctional, bifunctional, and trifunctional or higher functional oligomers are not particularly limited, but are, for example, oligomers formed from the above monomers such as linear acrylic oligomers, epoxy (meth) acrylates, and oxetane (meth). Examples thereof include acrylates, aliphatic urethane (meth) acrylates, aromatic urethane (meth) acrylates and polyester (meth) acrylates.

Further, an N-vinyl compound may be contained as another monofunctional monomer or polyfunctional monomer. The N-vinyl compound is not particularly limited, and examples thereof include N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, and derivatives thereof. Be done.

The ink composition may contain a monofunctional (meth) acrylate as a monofunctional monomer. In this case, the ink composition has a low viscosity, is excellent in solubility of a photopolymerization initiator and other additives, and is easy to obtain ejection stability during inkjet recording. The monofunctional (meth) acrylate is not particularly limited, and for example, benzyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, EO cresol (meth) acrylate, and ethoxylated phenyl (meth) acrylate. ) Acrylate, Nonylphenoxypolyethylene glycol (meth) acrylate, Nonylphenoxypolypolyglycol (meth) acrylate, Paracumylphenoxyethylene glycol (meth) acrylate, ECH-modified phenoxy (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) ) Acrylate, phenoxyhexaethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, tribromophenyl (meth) acrylate, EO-modified tribromophenyl (meth) acrylate, O-phenylphenol (meth) acrylate, 2- Examples thereof include monofunctional (meth) acrylates having an aromatic ring such as hydroxy-3-phenoxypropyl (meth) acrylate and O-phenylphenol EO-modified (meth) acrylate. Of these, phenoxyethyl (meth) acrylate is particularly preferred. When the ink composition of the present embodiment contains a monofunctional (meth) acrylate having an aromatic ring, storage stability can be further enhanced. The monofunctional (meth) acrylate having an aromatic ring may be used alone or in combination of two or more.

The content of the monofunctional (meth) acrylate having an aromatic ring is preferably 3.0 to 55% by mass, more preferably 5.0 to 50% by mass, based on the total amount of the ink composition. .. When this content is in the above range, it is possible to achieve both storage stability and curability at a higher level.

Examples of other monofunctional (meth) acrylates include isoamyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, and isomyristyl (meth). ) Acrylate, Isostearyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2-hydroxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate , Methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, lactone Modifyable flexible (meth) acrylate, t-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2- (isopropenoxyethoxy) ethyl (meth) acrylate , 2- (Isopropenoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxyethoxyethoxyethoxy) ethyl (meth) acrylate, polyethylene Glycol monovinyl ether (meth) acrylate and polypropylene glycol monovinyl ether (meth) acrylate can be mentioned.

The content of the monofunctional monomer is preferably 30 to 85% by mass, more preferably 40 to 75% by mass, based on the total amount (100% by mass) of the ink composition. By setting the above preferable range, the curability, initiator solubility, storage stability, and discharge stability tend to be more excellent.

The ink composition may contain a polyfunctional (meth) acrylate as a polyfunctional monomer. Among them, the bifunctional (meth) acrylate is not particularly limited, and for example, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and dipropylene glycol di (meth) acrylate. ) Acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol Di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-tricyclodecanedi (meth) acrylate, EO (ethylene oxide) adduct of bisphenol A di (meth) acrylate, PO (propylene oxide) of bisphenol A Additives Di (meth) acrylate, neopentyl glycol di (meth) acrylate of hydroxypivalate, polytetramethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth) acrylate can be mentioned.

Examples of the trifunctional or higher functional (meth) acrylate include trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate. , Dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerin propoxytri (meth) acrylate, cowprolactone-modified trimethylolpropane tri (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, and Caprolactam-modified dipentaerythritol hexa (meth) acrylate can be mentioned.

Among these, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and pentaerythritol tri (meth) acrylate are preferable, and dipropylene. Glycoldi (meth) acrylate and pentaerythritol tri (meth) acrylate are more preferred.

The content of the polyfunctional monomer is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, still more preferably 15 to 40% by mass, based on the total amount (100% by mass) of the ink composition. By setting the above preferable range, the curability, storage stability, ejection stability and surface gloss of the printed matter tend to be superior.

In addition, since the toughness, heat resistance, and chemical resistance of the cured film are increased, it is preferable to use monofunctional (meth) acrylate and bifunctional (meth) acrylate in combination, among which phenoxyethyl (meth) acrylate and dipropylene glycol are used. It is more preferable to use di (meth) acrylate in combination.

The content of the polymerizable compound is preferably 35 to 95% by mass, more preferably 45 to 90% by mass, based on the total amount (100% by mass) of the ink composition. When the content of the polymerizable compound is within the above range, the viscosity and odor can be further reduced, and the solubility and reactivity of the photopolymerization initiator and the surface gloss of the printed matter are further improved. Can be done.

(moisture)
The ink composition of the present embodiment contains water, and the water content is 0.05% by mass or more and 1.0% by mass or less with respect to the total amount (100% by mass) of the ink composition. This makes it possible to achieve both storage stability and curability of the ink composition at a high level. Further, the generation of foreign substances in the ink composition can be further suppressed, and the aggregation of the pigment when a pigment is used as the coloring material, particularly the aggregation of the pigment when a dispersant is used together with the pigment can be further suppressed. The discharge stability can be further improved. Further, when the ink composition contains an acylphosphine oxide-based photopolymerization initiator, the photopolymerization initiator can be satisfactorily dissolved in the ink composition. The water content is preferably 0.1% by mass or more from the viewpoint of further enhancing the storage stability and ejection stability of the ink composition and further suppressing the generation of foreign substances in the ink composition. On the other hand, from the viewpoint of further suppressing the generation of foreign substances and the aggregation of pigments, from the viewpoint of further enhancing the storage stability of the ink composition, and when the ink composition contains an acylphosphine oxide-based photopolymerization initiator, the photopolymerization is started. It is preferably 0.5% by mass or less because the agent is more well dissolved in the ink composition.

Examples of the method for adjusting the water content in the ink composition include, for example, each component of the ink composition, for example, the above-mentioned polymerizable compound, a method for reducing the water content in the ink composition, a method for removing water from the composition, and a composition. Examples thereof include a method of reducing the amount of water mixed in during preparation. Among these, as a method for reducing the amount of water in the polymerizable compound, more specifically, a method for distilling and purifying the polymerizable compound, a method for permeating the polymerizable compound through a semi-permeable film that selectively permeates water, and a method for permeating the polymerizable compound. A method of selectively adsorbing water to a water adsorbent that adsorbs water can be mentioned. Among these, the method of distillation purification is preferable from the viewpoint of being able to reduce the water content more efficiently and reliably. The water content is measured according to the method described in the examples below.

Examples of the water content include pure water such as ion-exchanged water, ultra-filtered water, reverse osmosis water, and distilled water, and ultrapure water from which ionic impurities have been removed as much as possible. Further, when water sterilized by irradiation with ultraviolet rays or addition of hydrogen peroxide or the like is used, it is possible to prevent the growth of mold and bacteria when the ink is stored for a long period of time. This tends to further improve storage stability.

In addition to the above-mentioned components, the ink composition of the present embodiment may contain any component that can be used in a conventional ultraviolet curable inkjet ink composition. Such optional components include, for example, polymerization initiators, colorants such as pigments and dyes, dispersants, polymerization inhibitors, surfactants, penetrants, moisturizers, solubilizers, viscosity modifiers, pH adjusters. Examples include agents, antioxidants, preservatives, fungicides, antioxidants, and chelating agents and other additives and solvents for capturing metal ions that affect dispersion. Each of these may be used alone or in combination of two or more.

(Polymerization initiator)
The ink composition of the present embodiment may contain a polymerization initiator. The polymerization initiator is not limited as long as it generates active species such as radicals and cations by heat energy or light energy such as ultraviolet rays and initiates the polymerization of the above-mentioned polymerizable compound, but the photopolymerization initiator is not limited. Is preferable, and a photoradical polymerization initiator is preferable. The photoradical polymerization initiator is not particularly limited, but an acylphosphine oxide-based photopolymerization initiator and a thioxanthone-based photopolymerization initiator are preferable, and an acylphosphine oxide-based photopolymerization initiator is more preferable.

[Acylphosphine oxide-based photopolymerization initiator]
The ink composition preferably contains an acylphosphine oxide-based photopolymerization initiator. Acylphosphine oxide-based photopolymerization initiators are susceptible to oxygen inhibition, but are suitable for curing with long-wavelength LEDs. Further, the acylphosphine oxide-based photopolymerization initiator can be better dissolved in the ink composition when the water content in the ink composition is 1.0% by mass or less with respect to the total amount of the ink composition. it can.

The acylphosphine oxide-based photopolymerization initiator is not particularly limited, but specifically, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. , And bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide.

The commercially available acylphosphine oxide-based photopolymerization initiator is not particularly limited, and for example, IRGACURE 819 (trade name manufactured by BASF, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE TPO ( Examples thereof include BASF trade name 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) and DAROCUR TPO (BASF trade name 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide).

The content of the acylphosphine oxide-based photopolymerization initiator is preferably 3.0 to 15% by mass, preferably 1.0 to 10% by mass, and 2.0 to 20% by mass, based on the total amount (100% by mass) of the ink composition. 8.0% by mass is more preferable. When the content is 3.0% by mass or more, the curability tends to be superior. Further, when this content is 15% by mass or less, the dissolution and storage stability of the solid content are kept good, and the reliability tends to be superior.

[Thioxanthone-based photopolymerization initiator]
The ink composition may contain a thioxanthone-based photopolymerization initiator. When the ink composition contains a thioxanthone-based photopolymerization initiator, surface tackiness can be reduced, and in particular, the ink surface can be cured at the time of a thin film susceptible to oxygen inhibition to prevent color mixing and bleeding between dots. .. Further, it is preferable to use both an acylphosphine oxide-based photopolymerization initiator and a thioxanthone-based photopolymerization initiator because the curing process by UV-LED tends to be superior and the curability and adhesion of the ink composition tend to be further excellent.

The thioxanthone-based photopolymerization initiator is not particularly limited, but specifically, it preferably contains one or more selected from the group consisting of thioxanthone, diethylthioxanthone, isopropylthioxanthone, and chlorothioxanthone. Although not particularly limited, 2,4-diethylthioxanthone is preferable as diethylthioxanthone, 2-isopropylthioxanthone as isopropylthioxanthone, and 2-chlorothioxanthone as chlorothioxanthone. An ink composition containing such a thioxanthone-based photopolymerization initiator tends to be more excellent in curability, storage stability, and ejection stability. Among these, a thioxanthone-based photopolymerization initiator containing diethyl thioxanthone is preferable. By including diethylthioxanthone, there is a tendency that ultraviolet light (UV light) in a wide range can be converted into an active species more efficiently.

The commercially available thioxanthone-based photopolymerization initiator is not particularly limited, but specifically, Speedcure DETX (2,4-diethyl thioxanthone), Speedcure ITX (2-isopropylthioxanthone) (all manufactured by Rambson), and KAYACURE. DETX (2,4-diethylthioxanthone) (manufactured by Nippon Kayaku Co., Ltd.) can be mentioned.

The content of the thioxanthone-based photopolymerization initiator is preferably 0.5 to 5.0% by mass, more preferably 1.0 to 4.0% by mass, based on the total amount (100% by mass) of the ink composition. When the content is 0.5% by mass or more, the surface tackiness can be further reduced, and the ink surface can be cured at the time of a thin film susceptible to oxygen inhibition to further prevent color mixing and bleeding between dots. It is in. Further, when the content is 5.0% by mass or less, the ink is less colored by the initiator itself, the hue is less yellowed, and the adhesion of the cured film tends to be superior.

(Other photopolymerization initiators)
The ink composition may further contain one or more photoradical polymerization initiators or photocationic polymerization initiators other than the above. Examples of photoradical polymerization initiators other than the above include aromatic ketones, aromatic onium salt compounds, organic peroxides, thio compounds (thiophenyl group-containing compounds, etc.), α-aminoalkylphenone compounds, and hexaarylbiimidazole. Examples thereof include compounds, ketooxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

Commercially available products of photoradical polymerization initiators other than the above are not particularly limited, but are, for example, IRGACURE 651 (2,2-dimethoxy-1,2-diphenylethane-1-one) and IRGACURE 184 (1-hydroxy-cyclohexyl). -Phenyl-ketone), DAROCUR 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one), IRGACURE 2959 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy- 2-Methyl-1-propane-1-one), IRGACURE 127 (2-hydroxy-1-{4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane -1-one}, IRGACURE 907 (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one), IRGACURE 369 (2-benzyl-2-dimethylamino-1- (4-) Morphorinophenyl) -butanone-1), IRGACURE 379 (2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone), IRGACURE 784 (bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium), IRGACURE OXE 01 (1. 2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]), IRGACURE OXE 02 (ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-) Carbazole-3-yl]-, 1- (O-acetyloxime)), IRGACURE 754 (oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2- (2-) A mixture of hydroxyethoxy) ethyl ester) (above, manufactured by BASF), Speedcure TPO (above, manufactured by Lambson), Lucirin TPO, LR8883, LR8970 (above, manufactured by BASF), and Yubekryl P36 (manufactured by UCB). Be done.

The other photocationic polymerization initiator is not particularly limited, and specific examples thereof include a sulfonium salt and an iodonium salt.

The content of the photopolymerization initiator is preferably 5 to 20% by mass with respect to the total amount (100% by mass) of the ink composition. When the content is within the above range, the ultraviolet curing rate tends to be sufficiently exhibited, and the undissolved residue of the photopolymerization initiator and the coloring derived from the photopolymerization initiator tend to be avoided.

(Color material)
The coloring material is not particularly limited, and examples thereof include pigments and dyes.

Examples of pigments include inorganic pigments and organic pigments. The inorganic pigment is not particularly limited, and examples thereof include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide.

The organic pigment is not particularly limited, but for example, quinacridone pigment, quinacridone quinone pigment, dioxazine pigment, phthalocyanine pigment, anthrapyrimidine pigment, anthanthrone pigment, indanslon pigment, flavanthron pigment, etc. Examples thereof include perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. ..

Pigments may be used alone or in combination of two or more.

The content of the pigment is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, and 1.0 to 5.0% by mass with respect to the total amount (100% by mass) of the ink composition. Is more preferable. When the content of the pigment is within the above range, the color development property tends to be superior.

The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. As the dye, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52,80,82,249,254,289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1,2,24,94, C.I. I. Hood Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1,2,15,71,86,87,98,165,199,202, C.I. I. Direct Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.

Dyes may be used alone or in combination of two or more.

The content of the dye is preferably 1.0 to 20% by mass with respect to the total amount (100% by mass) of the ink composition from the viewpoint of obtaining excellent hiding power and color reproducibility.

(Dispersant)
When the ink composition contains a pigment, one or more dispersants may be further contained in order to improve the dispersibility of the pigment. The dispersant is not particularly limited, and examples thereof include dispersants commonly used for preparing a pigment dispersion such as a polymer dispersant. Specific examples thereof include polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, sulfur-containing polymers, fluorine-containing polymers, and epoxies. Examples thereof include resins containing one or more of the main components. Commercially available polymer dispersants include Ajinomoto Fine-Techno's Azisper series, Avecia and Noveon's Solspers series (eg, "Solsperse 36000"), and BYK Chemie's Disper. The BIC series and the Disparon series manufactured by Kusumoto Kasei Co., Ltd. can be mentioned.

(Polymerization inhibitor)
The ink composition may contain one or more polymerization inhibitors from the viewpoint of further enhancing the storage stability thereof. The polymerization inhibitor is not particularly limited, but for example, a compound having a 2,2,6,6-tetramethylpiperidine-N-oxyl skeleton, a compound having a 2,2,6,6-tetramethylpiperidine skeleton, 2 , Hindered amine compounds such as compounds with a 2,6,6-tetramethylpiperidine-N-alkyl skeleton and compounds with a 2,2,6,6-tetramethylpiperidine-N-acyl skeleton; p-methoxyphenol, hydroquinone Monomethyl ether (MEHQ), hydroquinone, cresol, t-butylcatechol, 3,5-di-t-butyl-4-hydroxytoluene, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2, Examples thereof include 2'-methylenebis (4-ethyl-6-butylphenol) and 4,4'-thiobis (3-methyl-6-t-butylphenol).

The ink composition of the present embodiment is contained in an container. In other words, the container of the present embodiment contains the ink composition of the present embodiment.

(Container)
The embodiment of the housing of the present embodiment is not limited to the following, and examples thereof include ink cartridges, packs, bottles, tanks, bottles, and cans. Among these, ink cartridges, packs, bottles, and tanks are preferable, and packs are more preferable, because they are widely used and the water vapor transmittance described later can be easily controlled to a desired value. Further, as a container (a member in which the ink composition is filled and substantially holding the composition in the container) filled with the ink composition of the container, a container (pack) using a flexible film is provided. The container is lightweight, the container can be easily put into the box-shaped container, the volume of the container easily changes according to the remaining amount of the ink composition, and the film is heat-sealed to make a bag. It is preferable in that it can be processed into a shape and used.

In addition, as the usage mode of the housing of the present embodiment, there is a form such as an ink cartridge which is separate from the recording device and is attached to the recording device to sequentially supply the ink composition to the recording device. B) It is a separate body from the recording device, and when the ink composition is used, only the ink composition is transferred from the container to the recording device, and (C) a tank or the like provided in the recording device in advance and containing the ink composition, etc. At least the morphology.

The above (A) and (B) can be said to be an ink composition container from the time the container is shipped until immediately before the ink composition is supplied (transferred) to the recording device. The above (C) can be said to be an ink composition accommodating body from the time when the recording device is shipped to the time when the recording device starts using the ink composition for the first time. In the above (A) and (C), the ink composition container for printing the recording device while the ink composition is supplied from the container to the recording device via a connecting portion such as an ink tube. It can be said. Further, the above-mentioned (B) can be said to be an ink composition container for printing on the recording device after transferring the ink composition from the container to the recording device. The target for transferring the ink composition in (B) includes a tank provided in the recording device and the like.

The constituent material of the container filled with the ink composition is not limited to, for example, polyethylene terephthalate (PET), polypropylene (PP), polyethylene, ethylene vinyl acetate copolymer, ethylene vinyl alcohol copolymer (EVOH). ), And polystyrene, and these films may be used. The above may be blended in an appropriate ratio, or a plurality of types of the above may be stacked to form a structure. In the case of a film, it may be obtained by laminating. When a plurality of types of films are stacked, it is not necessary that all of the plurality of types of films are the above-mentioned films, and a part thereof may be a film composed of other materials, for example, metals and metal compounds.

Further, from the viewpoint of increasing the flexibility of the container, it is preferable that a plasticizer is contained as a constituent material of the container. Examples of the plasticizer include fatty acid esters, epoxy compounds, and polyester compounds. Among these, fatty acid esters are preferable from the viewpoint of versatility as a plasticizer, and examples of such fatty acid esters include phthalates, adipates, trimellitic acids, and citrates. The fatty acid ester may be used alone or in combination of two or more.

The container may be agitated during storage and transportation in order to release the sedimentation of the components contained in the ink composition to be contained. This is because, after a long period of time has passed after the components contained in the ink composition have settled, the settled matter may become a cake and it may be difficult to release the settled matter. Further, when the ink composition is supplied from the container to the recording device, it is preferable to stir the container to release the sedimentation.

When the container is a container (pack) using a flexible film, durability that does not cause cracks or tears is required especially with the stirring operation. Examples of such a durable film material include plastic films such as polyethylene terephthalate (PET), polypropylene, polyethylene, ethylene vinyl acetate copolymer, ethylene vinyl alcohol copolymer, and polystyrene, and ethylene acetic acid is preferable. Vinyl copolymers are more preferred. Preferable examples of the film include stretched plastic films such as high-density, low-density, or linear low-density polyethylene, polypropylene, ethylene-vinyl alcohol copolymer, and polystyrene. It may be a laminated film in which a plurality of layers of films are laminated.

Further, the container may further include a sealing member, and at least a container filled with the ink composition may be housed and sealed in the sealing member (hereinafter, this is particularly referred to as a "sealed container"). That is, the sealed container of the present embodiment is a sealed container including a container, the ink composition filled in the container, and at least a sealing member for storing and sealing the container. The constituent material of the sealing member in the sealed container is not particularly limited, and may be the same as the constituent material of the container or the container. When the housing body includes a sealing member, at least the container may be stored and sealed in the sealing member. For example, a portion of the housing body other than the container may also be stored and sealed in the sealing member. , The entire container may be housed and sealed in a sealing member. Further, the mode of the sealing member is not particularly limited, but when the entire housing is stored, the size of the sealing housing can be reduced, and the sealing member itself is maintained in a sealed property. It is preferable that the bag is made of a flexible film that can follow the outer shape and adhere to the container. In addition, when storing a part of the container such as a container, from the viewpoint of reducing the size of the part to be stored, use a flexible film bag that can follow the outer shape of the part to be stored and adhere to it. It is preferable to have.

When the container is the above-mentioned pack, or when the sealing member is the above-mentioned film bag, or when the components contained in the ink composition settle, the pack or the sealed container is shaken from side to side to stir the ink. It may be recovered by sedimentation. In that case, it is preferable to contain a plasticizer as a constituent material of the pack or bag from the viewpoint of preventing cracks or tears in the pack or bag. As the plasticizer, any of the above-mentioned plasticizers may be used, and fatty acid esters are preferable.

Member constituting the container, for example, a film when the container is a pack constituting the pack or the sealing member of the sealed container, for example, a film bag, the water vapor transmission rate of, 30g / m ² · 24hrs preferably less, more preferably at most 15g / m ² · 24hrs, more preferably at most 10g / m ² · 24hrs, and particularly preferably not more than 5.0g / m ² · 24hrs .. By water vapor transmission rate using the following member 30g / m ² · 24hrs, even when the container or sealing container long-term storage, to suppress the increase of the water content in the ink composition filled in the container Can be done. The water vapor transmission rate to less 30g / m ² · 24hrs, for example, to select the material forming the member or sealing member constituting the container, to those members, is composed of at least one of metals and metal compounds A layer may be provided. Among these, from the viewpoint of versatility, it is preferable to provide a layer composed of at least one of a metal and a metal compound. Examples of the metal include Al and Ti. The metal compound is preferably a metal oxide, and examples thereof include alumina, silica, titania and zirconia. These may be used alone or in combination of two or more.
The thickness of the film constituting the pack is preferably 50 to 200 μm, more preferably 70 μm or more, further preferably 80 μm or more, preferably 150 μm or less, still more preferably 130 μm or less. The thickness of the film is the total thickness when the film is a laminated film composed of a plurality of layers. When the thickness of the film is in the above range, it is preferable from the viewpoint of durability and flexibility of the film.

Here, the water vapor transmittance is a value measured with a thickness equivalent to 100 μm in an environment of 40 ° C. and a relative humidity of 90%. For example, transportation / industrial packaging technology (supervised by Shinichi Mizuguchi, Fuji Techno Systems Co., Ltd.) It is also possible to use materials that satisfy the above water vapor permeability from the materials listed in (Issued).

The volume of the composition that can be contained in the inclusion body is not limited to the following, but is preferably 100 to 5000 mL, the upper limit is more preferably 4000 mL or less, further preferably 3000 mL or less, particularly preferably 2000 mL or less, still more preferably 1000 mL or less. The lower limit is more preferably 200 mL or more, further preferably 500 nL or more. When the capacity is within the above range, the curability, storage stability, and discharge stability can all be further improved.

Here, an ink cartridge which is an example of the housing of the present embodiment will be described. FIG. 1 is an exploded perspective view showing an ink cartridge 40. The ink cartridge 40 includes an ink pack 70 filled with ink, a cartridge case 72 including a main body case 76 and a lid 78 for containing and protecting the ink pack 70 inside, and the ink pack 70 includes an ink supply port 74. The main body case 76 includes a notch 80 and a groove 86, and the lid 78 includes a holding portion 82 and a hook portion 84. The above-mentioned materials can be used as the material of the ink pack. In the ink cartridge 40, the ink pack 70 is housed in the main body case 76 and the lid portion 84, and at that time, the ink supply port 74 is fitted into the notch portion 80, and then the pressing portion 82 and the notch portion 80 are formed. It is fixed by being pinched. Further, the main body case 76 and the lid portion 84 are sealed by fitting the hook portion 84 into the groove portion 86.

As described above, according to the present embodiment, it is possible to provide an container containing an ink composition capable of achieving both curability and storage stability at a high level.

[Inkjet method]
The inkjet method of the present embodiment includes an adhesion step of adhering the composition to the ejected body. Hereinafter, although it is described as an inkjet recording method as one embodiment of the inkjet method, the inkjet method may be other than the inkjet recording method. In the inkjet recording method, recording is usually performed using an inkjet recording device. More specifically, the inkjet recording method includes an adhesion step of ejecting the ink composition from a nozzle of a head and adhering the ink composition to a recording medium. The inkjet recording method of the present embodiment preferably includes an irradiation step of irradiating the ink composition adhering to the recording medium with light to cure the ink composition.

(Adhesion process)
In the adhesion step, first, the ink composition of the present embodiment is ejected from the nozzle of the head. As the ejection method, a piezo method, a method of ejecting the ink composition from bubbles generated by heating the ink composition, or the like can be used. Among these, the piezo method is preferable from the viewpoint of difficulty in deteriorating the ink composition.

The ink composition ejected from the nozzle adheres to the ejected body. Examples of the ejected body include a recording medium and the like. Hereinafter, the recorded medium will be described as one embodiment of the ejected body, but the ejected body may be a medium other than the recorded medium. Examples of the recording medium include an absorbent or non-absorbable recording medium. The absorbent recording medium is not particularly limited, but for example, plain paper such as electrophotographic paper having high permeability of the ink composition, inkjet paper (ink composition absorbing layer composed of silica particles or alumina particles, or an ink composition absorbing layer composed of silica particles or alumina particles, or , Ink composition paper with an ink composition absorbing layer composed of hydrophilic polymers such as polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP)), general offset with relatively low permeability of the ink composition composition. Examples include art paper, coated paper, and cast paper used for printing. The non-absorbent recording medium is not particularly limited, but for example, a plastic film or plate such as polyvinyl chloride, polyethylene, polypropylene or polyethylene terephthalate (PET), or a metal such as iron, silver, copper or aluminum. Examples thereof include plates of the same kind, metal plates produced by vapor deposition of various metals thereof, plastic films, alloy plates such as stainless steel and true casting, and the like.

(Irradiation process)
In the irradiation step, the polymerizable compound is polymerized by irradiating the ink composition adhering to the recording medium with light to cure the ink composition. The light source is not particularly limited as long as it has an emission wavelength in the ultraviolet wavelength region. Among them, ultraviolet light emitting diodes (UV-LED) and ultraviolet laser diodes (UV-LD) are compact, have a long life, have high efficiency, and are low in cost, and are expected as light sources for ultraviolet curable inkjet. Among these, UV-LED is preferable.

Here, it is preferable to use an ink composition having an emission peak wavelength preferably in the range of 360 to 450 nm, which can be cured by irradiating with light. The irradiation energy is preferably 500 mJ / cm ² or less. Under such irradiation conditions, it is possible to cure with low energy and high speed. The irradiation energy is calculated by multiplying the irradiation time by the irradiation intensity. Depending on the composition of the ink composition, the irradiation time can be shortened and the recording speed can be increased. On the other hand, the irradiation intensity can be reduced by the composition of the ink composition, and in this case, the device can be downsized and the cost can be reduced. It is preferable to use a UV-LED for light irradiation at that time. Such an ink composition is obtained by containing a photoradical polymerization initiator that decomposes by light irradiation in the wavelength range, and a compound having a polymerizable functional group that initiates polymerization by light irradiation in the wavelength range. The emission peak wavelength may be one or a plurality within the above wavelength range. Even if there are a plurality of light, the total irradiation energy of the light having the emission peak wavelength is defined as the irradiation energy.

The inkjet recording method of the present embodiment may include a heating step of heating the recording medium in addition to the irradiation step described above. As a result, the ink composition adhering to the recording medium can be heated, and the curability can be further improved.

The inkjet recording method of the present embodiment is a recording method capable of achieving both curability and ejection stability at a high level by recording by an inkjet method using the above-mentioned ink composition.

The inkjet recording device of the present embodiment may be any device that can be used in the above-mentioned inkjet recording method, and the configuration other than using the ink composition of the present embodiment is not particularly limited. For example, as other configurations, conventionally known configurations may be provided.

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

[Material for UV curable inkjet ink composition]
The main materials for the ink composition used in the following examples and comparative examples are as follows.
[Color material]
P. I. Pigment Blue 15: 4
[Polymerizable compound]
VEEA (2- (2-vinyloxyethoxy) ethyl acrylate, manufactured by Nippon Shokubai Co., Ltd., number of functional groups 1)
PEA (phenoxyethyl acrylate, manufactured by Osaka Organic Chemical Co., Ltd., number of functional groups 1)
DPGDA (dipropylene glycol diacrylate, manufactured by Sartmer, 2 functional groups)
SR444 (pentaerythritol triacrylate, manufactured by Nippon Kayaku Co., Ltd., number of functional groups 3)
V # 335HP (Product name "Viscoat # 335HP", Tetraethylene glycol diacrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., number of functional groups 2)
DVE-3 (Triethylene glycol divinyl ether, manufactured by BASF)
[Polymerization initiator]
IRGACURE TPO (BASF product name, solid content 100% by mass)
IRGACURE 369 (BASF product name, solid content 100% by mass)
KAYACURE DETX (Product name manufactured by Nippon Kayaku Co., Ltd., solid content 100% by mass)
[Dispersant]
solspec 36000 (Product name manufactured by Noveon)
[Polymerization inhibitor]
MEHQ (hydroquinone monomethyl ether, manufactured by Tokyo Chemical Industry Co., Ltd.)

(Examples 1 to 9, Comparative Examples 1 to 6)
[Preparation of ink composition]
Each material was mixed with the composition (mass%) shown in Tables 1 and 2 below and sufficiently stirred to obtain each ink composition. Each polymerizable compound used in each Example and Comparative Example was distilled and purified once or multiple times and then mixed with other materials so that the water content of the ink composition was as shown in Tables 1 and 2. did.

(Measurement of water content)
The moisture content in the ink composition was measured by the Karl Fischer titer method using a moisture meter (product name "automatic heating vaporization moisture measurement system AQS-2210" manufactured by Hiranuma Sangyo Co., Ltd.). The results are shown in Tables 1 and 2 (mass basis).

(Evaluation of storage stability)
The ink composition immediately after preparation was contained in a glass bottle, the glass bottle was sealed, and the ink composition was stored at 50 ° C. for 5 weeks. The viscosity of the ink composition before and after storage at 20 ° C. was measured with a viscoelasticity tester (product name "MCR-30") manufactured by physica, and the viscosity of the ink composition before storage was measured after storage. It was calculated how much the viscosity of the ink composition increased, that is, what percentage the viscosity increased. Based on the results, evaluation was made according to the following evaluation criteria. The results are shown in Tables 1 and 2.
A: Thickening is less than 5%.
B: Thickening is 5% or more and less than 10%.
C: Thickening is 10% or more.

(Evaluation of discharge stability)
A head having 360 nozzles is fixed to the upper part, a PET film (part number "PET50 K2411 PAT1E", manufactured by Lintec Corporation) is conveyed below the nozzles of the head at 15 m / min, and 10 kHz is transmitted from 180 nozzles to the PET film. The ink composition was ejected in 1 and continuous printing was performed. At the same time as printing, an image was formed by irradiating the ink composition adhered to the PET film with an LED having an emission wavelength peak of 395 nm. Every 5 minutes from the start of ejection, it was visually confirmed whether or not the ink composition was ejected from all the nozzles, and the evaluation was made according to the following evaluation criteria. The results are shown in Tables 1 and 2. Further, when the ink composition was observed with an optical microscope, pigment particles (pigment aggregates) having a larger particle size than usual were confirmed in those whose ejection stability was evaluated as C.
A: Nozzle omission for 50 minutes or more.
B: Nozzle is missing in 20 minutes or more and less than 50 minutes.
C: Nozzle is missing in less than 20 minutes.

(Evaluation of pigment aggregation)
The ink composition immediately after preparation was filtered using a filter paper (No. 5A manufactured by Advantech Co., Ltd.), and then foreign substances remaining on the filter paper were visually observed. Based on the observation results, evaluation was made according to the following evaluation criteria.
A: No foreign matter was found.
B: Some foreign matter was found.
C: Many foreign substances were found.

(Evaluation of curability)
Using a bar coater, the ink composition was applied onto a PET film (PET50A PL thin [trade name], manufactured by Lintec Corporation) so that the thickness after curing was 8 μm to prepare a coating film. Then, the coating film was cured by irradiating with ultraviolet rays having an irradiation intensity of 1100 mW / cm ² and a wavelength of 395 nm. The cured coating film (cured film) was rubbed 10 times with a weight of 100 g using a cotton swab to determine the curing energy (irradiation energy) at the time when no scratches were formed.
The irradiation energy [mJ / cm ² ] was obtained by measuring the irradiation intensity [mW / cm ² ] on the irradiated surface irradiated from the light source and multiplying this by the irradiation duration [s]. The irradiation intensity was measured using an ultraviolet intensity meter UM-10 and a light receiving unit UM-400 (both manufactured by Konica Minolta SENSING, INC.). Based on the result of irradiation intensity, it was evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2.
A: 200mJ / cm ² or less B: 200mJ / cm ² to greater than 300 mJ / cm ² or less C: 300mJ / cm ² than

In addition, two films (material: high-density polyethylene, plasticizer: diethyl adipic acid, thickness: 100 μm) were cut into rectangles of the same size, and their three sides were heat-sealed to prepare a pack. .. The pack was filled with 700 mL of the ink composition of Example 1 or Comparative Example 1, and the remaining sides were heat-sealed to seal the pack. An aluminum vapor deposition film (thickness: 12 μm) was formed on the outer side of the pack to obtain an aluminum vapor deposition pack filled with the ink composition. As for the laminated film obtained in the same manner to the film to form an aluminum deposited film was measured for water vapor transmission rate was 0.5g / m ² · 24hrs. On the other hand, packs filled with the ink compositions of Example 1 and Comparative Example 1 were obtained in the same manner as described above except that the aluminum vapor deposition film was not formed. Incidentally, without forming the aluminum deposited layer on the film was measured for water vapor permeability of the film was 35g / m ² · 24hrs.

A total of 4 packs were stored for 6 months in an environment with a temperature of 40 ° C. and a relative humidity of 90%. When the water content of the ink composition in the pack after storage was measured, only the ink composition of Example 1 filled with the ink composition of Example 1 without forming the aluminum vapor deposition film exceeded 1% by mass. Therefore, water vapor transmission rate of the film constituting the pack, it was found that it is preferably not more than 30g / m ² · 24hrs.

By comparing Examples 1 and 6 to 9 with Comparative Examples 1 to 3 and 6, it was found that when the ink composition contained VEEA, the ink composition was particularly excellent in curability. Further, by comparing Examples 1 to 5 with Comparative Examples 4 and 5, the water content is 0.05% by mass or more and 1.0% by mass or less, so that the discharge stability and the storage stability are particularly stable. It was found that it was excellent in suppressing pigment aggregation, ejection stability and curability.

From the comparison between Comparative Example 4 and Comparative Example 6, when the ink composition does not contain VEEA, even if the water content is 0.05% by mass or less, the storage stability and ejection stability are not inferior. It turned out not. Furthermore, the content of Irgacure TPO (trade name) was changed from 4.0% by mass to 9.0% by mass, and the content of Irgacure 369 (trade name) was changed from 6.0% by mass to 1.0% by mass. It was confirmed that in the ink composition prepared in the same manner as in Comparative Example 5 except that the photopolymerization initiator, mass36000 (trade name) was difficult to dissolve.

40 ... ink cartridge, 70 ... ink pack, 72 ... cartridge case, 74 ... ink supply port, 76 ... main body case, 78 ... lid, 80 ... notch, 82 ... holding part, 84 ... hook, 86 ... groove ..

Claims (9)

With the container
An accommodating body comprising an inkjet composition filled in the container.
The container, water vapor transmission rate of the members constituting the, 40 ° C., and a ^30g / m 2 · 24hrs or less under a relative humidity of 90% for,
The inkjet composition contains a polymerizable compound, a photopolymerization initiator and,
The polymerizable compound contains a polymerizable compound having a vinyl ether group and a (meth) acryloyl group, and a monofunctional monomer.
The content of the monofunctional monomer is 30% by mass or more based on the total amount of the composition.
An inclusion body in which the content of the monofunctional (meth) acrylate having an aromatic ring contained as the monofunctional monomer is 5% by mass or more based on the total amount of the composition. With the container
A sealing member that stores and seals the container,
An accommodating body comprising an inkjet composition filled in the container.
The sealing member, the water vapor transmission rate, 40 ° C., and a ^30g / m 2 · 24hrs or less under a relative humidity of 90% for,
The inkjet composition contains a polymerizable compound having a vinyl ether group and a (meth) acryloyl group, a monofunctional (meth) acrylate having an aromatic ring, and a photopolymerization initiator.
An inclusion body in which the content of the monofunctional (meth) acrylate having an aromatic ring is 5% by mass or more based on the total amount of the composition. The container according to claim 1 or 2, wherein the inkjet composition is a radical polymerization type ultraviolet curable composition. The container according to any one of claims 1 to 3, wherein the photopolymerization initiator is an acylphosphine oxide-based photopolymerization initiator. The container according to any one of claims 1 to 4, which contains the polymerizable compound in an amount of 50 to 70% by mass based on the total amount of the inkjet composition. As the polymerizable compound, the following general formula (1):
CH ₂ = CR ^1- COOR ^2- O-CH = CH-R ³ ... (1)
(In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. The container according to any one of claims 1 to 5, which contains a polymerizable compound represented by (). The container according to any one of claims 1 to 6, wherein the water content is 0.05% by mass or more and 0.5% by mass or less with respect to the total amount of the inkjet composition. An inkjet method comprising an attachment step of adhering the inkjet composition according to any one of claims 1 to 7 to an object to be ejected. The inkjet method according to claim 8, further comprising a curing step of irradiating the inkjet composition adhered to the ejected body with light by an ultraviolet light emitting diode having an emission peak wavelength in the range of 360 to 420 nm to cure the composition.

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