JP7098103B2 - Curable composition, curable ink, composition container, 2D or 3D cured product manufacturing method, 2D or 3D image forming device and cured product - Google Patents

Description

The present invention relates to a curable composition, a curable ink, a composition container, a method for producing a two-dimensional or three-dimensional cured product, a two-dimensional or three-dimensional image forming apparatus, and a cured product.

Photopolymerizable compositions and inkjet inks containing an acrylic acid ester compound as a main component are widely known (see Patent Document 1). From the viewpoint of quick-drying, such photopolymerizable inkjet inks are usually in a form that does not contain volatile solvents such as water and organic solvents, and as a result, in inkjet systems, a drying unit that uses a heat source or the like is used. It is only necessary to provide a light source that irradiates light such as ultraviolet rays, and there are many advantages such as miniaturization and cost reduction of equipment. The fact that it does not contain a volatile solvent is also an advantage in that it is possible to avoid ejection problems due to volatile thickening at the gas-liquid interface of the nozzle portion of the inkjet head.

However, in the field where photopolymerizable inkjet ink is put into practical use, ejection defects often occur and the causes vary depending on the situation, but it is generally known that defects are likely to occur especially when a large amount of pigment is contained. In order to form an image with a richer or clearer color tone, it is effective to add a large amount of pigment to the ink, but since there is a reciprocal relationship with the ejection property, this is compatible at a higher level. It is an important task to do.
Among them, for yellow ink, which is one of the process colors, pigments such as Pigment Yellow 150 and Pigment Yellow 155 are often used as yellow pigments, but other process colors, especially The pigment content must be higher than that of cyan or black, and yellow ink is prone to ejection problems.
Problems with ejection of the nozzle of the inkjet head include non-ejection in which ink does not come out from the nozzle hole, bending in which ink droplets fly in different directions that are not vertical to the nozzle surface, and ink droplets that are different from the intended speed. There are abnormal flying speeds, etc., and any of these problems can lead to image distortion due to ink not landing at the intended position on the substrate or ink landing at an unintended position. It is more important to prevent ejection problems as high-definition image formation is required.

INDUSTRIAL APPLICABILITY The present invention is a curable composition, a curable ink, a composition accommodating container, a method for producing a two-dimensional or three-dimensional cured product, which can form an image at a high image density and has good ejection properties, or two-dimensional or It is an object of the present invention to provide a three-dimensional image forming apparatus and a cured product.

（但し、Ｘ、Ｙ、Ｚは水素原子、メチル基、メトキシ基、塩素原子のいずれかである。） The above problem is solved by the invention of the following (1).
(1) Containing a polymerizable compound and a photopolymerization initiator having 0.5% by weight or more and 3% by mass or less of a pigment having a chemical structure represented by the following general formula and absorption at a wavelength of 360 nm or more and 400 nm or less. Curable composition.

(However, X, Y, and Z are any of a hydrogen atom, a methyl group, a methoxy group, and a chlorine atom.)

According to the present invention, a curable composition, a curable ink, a composition accommodating container, a method for producing a two-dimensional or three-dimensional cured product, which can form an image with a high image density and has good ejection properties, 2 A dimensional or three-dimensional image forming apparatus and a cured product can be provided.

It is a schematic diagram which shows an example of the image forming apparatus in this invention. It is a schematic diagram which shows an example of another image forming apparatus in this invention. It is a schematic diagram which shows an example of still another image forming apparatus in this invention.

Hereinafter, a method for producing the cured composition according to the present invention, a two-dimensional or three-dimensional cured product, and a two-dimensional or three-dimensional image forming apparatus will be described in detail. It should be noted that the present invention is not limited to the embodiments shown below, and can be modified within the range conceivable by those skilled in the art, such as other embodiments, additions, modifications, and deletions. However, as long as the action and effect of the present invention are exhibited, it is included in the scope of the present invention.

Although the present invention relates to the curable composition described in (1) above, the following (2) to (11) are included as embodiments of the invention, and these embodiments will also be described.
(2) The curable composition according to (1) above, wherein the photopolymerization initiator is liquid at 23 ° C.
(3) The curable composition according to (2) above, wherein the photopolymerization initiator is ethyl 2,4,6-trimethylbenzoylphenylphosphinate.
(4) A curable ink comprising the curable composition according to any one of (1) to (3) above.
(5) The curable ink according to (4) above, which is an inkjet ink.
(6) A composition storage container containing the curable composition or curable ink according to any one of (1) to (5) above.
(7) The step of ejecting the curable composition or the curable ink according to any one of (1) to (5) above, and the ejected curable composition or the curable ink having a wavelength of 360 nm or more and 400 nm or less. A method for producing a two-dimensional or three-dimensional cured product, which comprises a step of irradiating with light.
(8) The method for producing a two-dimensional or three-dimensional cured product according to (7) above, wherein the ejection step is a ejection step of ejection by an inkjet recording method.
(9) The composition accommodating container according to (6) above, a means for ejecting the curable composition or curable ink contained in the composition accommodating container, and the ejected curable composition or curable type. A two-dimensional or three-dimensional image forming apparatus comprising a means for irradiating an ink with light having a wavelength of 360 nm or more and 400 nm or less.
(10) The two-dimensional or three-dimensional image forming apparatus according to (9) above, wherein the ejection means ejects a curable composition or a curable ink by an inkjet recording method.
(11) The curable composition or the cured product of the curable ink according to any one of (1) to (5) above.

(Pigment)
As the yellow pigments that can be used for yellow ink, the pigments Yellow 150 and Pigment Yellow 155 are often used because the pigments have excellent light resistance, but other pigments can be used depending on the application, and the coloring power is strong. By using a yellow pigment that can obtain a sufficient image density even with a smaller amount of pigment compounded and producing a yellow ink with a smaller pigment compounding ratio, both high image density and good ejection property can be achieved.

（但し、Ｘ、Ｙ、Ｚは水素原子、メチル基、メトキシ基、塩素原子のいずれかである。） In the present invention, a pigment having a chemical structure represented by the following general formula (1) is used as a yellow pigment that has strong coloring power and can be used for yellow ink that can obtain a sufficient image density even with a smaller amount of pigment compounded. do.

(However, X, Y, and Z are any of a hydrogen atom, a methyl group, a methoxy group, and a chlorine atom.)

Pigment Yellow 12 (X is H, Y is H, Z is H in the general formula) and Pigment Yellow 13 (X is CH ₃ and Y in the general formula) are pigments represented by the general formula (1). CH ₃ , Z is H), Pigment Yellow 83 (X is OCH ₃ , Y is Cl, Z is OCH ₃ in the above general formula) and the like.

The pigment represented by the above general formula (1) does not have good light resistance, but if it is an ultraviolet ray having a long wavelength of 360 nm or more and 400 nm or less, it is irradiated with ultraviolet rays having the minimum illuminance and light amount necessary for curing the ink. But there is no deterioration. Further, since this pigment is deeply colored, the amount of the pigment blended in the ink can be reduced to 1% by mass or more and 3% by mass or less. Therefore, the ink ejection property is also good.

(Polymerizable compound)
Examples of the polymerizable component include 2-phenoxyethyl acrylate (PEA), tetrahydrofurfuryl acrylate (THFA), isobornyl acrylate (IBXA), vinyloxyethoxyethyl acrylate (VEEA), isodecyl acrylate (IDA), and N-. Examples thereof include vinyl caprolactam (NVC), tripropylene glycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA) and the like.

Further, in addition to the above-mentioned polymerizable compound, the following (meth) acrylate, (meth) acrylamide, and vinyl compound can be used in combination.
Ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, γ-butyrolactone acrylate, formalized trimethylol propane mono (meth) acrylate, polytetramethylene glycol di (meth) acrylate, trimethyl propane ( Meta) Acrylic acid benzoic acid ester, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate [CH ₂ = CH-CO- (OC ₂ H ₄ ) n-OCOCH = CH ₂ (n) ≈9), same (n≈14), same (n≈23)], dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol dimethacrate [CH ₂ = C (CH ₃ ) ) -CO- (OC ₃ H ₆ ) n-OCOC (CH ₃ ) = CH ₂ (n≈7)], 1,3-butanediol diacrylate, 1,4-butanediol di (meth) acrylate, 1, 6-Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, propylene oxide-modified bisphenol A di (meth) acrylate, polyethylene glycol di (meth) acrylate, Dipentaerythritol hexa (meth) acrylate, (meth) acryloylmorpholine, 2-hydroxypropyl (meth) acrylamide, propylene oxide-modified tetramethylolmethanetetra (meth) acrylate, dipentaerythritol hydroxypenta (meth) acrylate, caprolactone-modified dipenta Elythritol hydroxypenta (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylol propanetriacrylate, ethylene oxide-modified trimethylol propanetriacrylate, propylene oxide-modified trimethylol propanetri (meth) Acrylate, caprolactone-modified trimethylol propantri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, ethoxylated neopentyl glycol di (meth) a Crylate, propylene oxide modified neopentyl glycol di (meth) acrylate, propylene oxide modified glyceryl tri (meth) acrylate, polyester di (meth) acrylate, polyester tri (meth) acrylate, polyester tetra (meth) acrylate, polyester penta (meth) Acrylic, polyester poly (meth) acrylate, (meth) acryloylmorpholine, hydroxyethyl (meth) acrylamide, N-vinylcaprolactum, N-vinylpyrrolidone, N-vinylformamide, polyurethane di (meth) acrylate, polyurethane tri (meth) acrylate , Polyurethane tetra (meth) acrylate, polyurethane penta (meth) acrylate, polyurethane poly (meth) acrylate, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, hydroxyethylvinyl ether, diethylene glycol monovinyl ether, diethylene glycol di Vinyl ether, dicyclopentadiene vinyl ether, tricyclodecane vinyl ether, benzyl vinyl ether, ethyloxetane methyl vinyl ether, triethylene glycol divinyl ether, hydroxybutyl vinyl ether, ethyl vinyl ether, etc.

(Photopolymerization initiator)
Examples of the photopolymerization initiator include a molecular cleavage type photopolymerization initiator and a hydrogen abstraction type photopolymerization initiator. The photopolymerization initiator is preferably in a liquid state at room temperature (23 ° C.). In the solid state, it is difficult to uniformly dissolve even if a large amount is blended due to the limitation of solubility, but the liquid state improves the solubility in ink, and stable solubility can be maintained even if a large amount is blended.

Examples of the molecular cleavage type photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenylketone, and 2-hydroxy-2-methyl-1-phenylpropane-. 1-on, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1- {4- [4- (2- (2-) Hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methyl-1-propane-1-one, phenylglycic acid methyl ester, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino Propane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4) -Il-phenyl) butane-1-one, bis (2,4,6-trimethylbenzoyl) phenylphosphinoxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphinoxide, diphenyl (2,4,6-trimethylbenzoyl) phosphinoxide ”“ Bis (2,4,6-trimethylbenzoyl) phenylphosphinoxide, 2,4,6-trimethylbenzoylphenylphosphinate ethyl, 1,2-octanedione -[4- (Phenylthio) -2- (o-benzoyloxime)], [Etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl], -1-( O-Acetyloxym)], [4- (Methylphenylthio) phenyl] phenylmethanone and the like.
Examples of the hydrogen abstraction type photopolymerization initiator include benzophenone compounds such as benzophenone, methylbenzophenone, methyl-2-benzoylbenzoate, 4-benzoyl-4'-methyldiphenylsulfide, and phenylbenzophenone, and 2, Examples thereof include thioxanthone-based compounds such as 4-diethylthioxanthone, 2-chlorothioxanthone, isopropylthioxanthone, and 1-chloro-4-propylthioxanthone.
Preferred photopolymerization initiators are those that are liquid at room temperature, have good solubility in ink, and have good sensitivity to long-wavelength light, and particularly preferably 2,4,6-trimethylbenzoyl. Ethyl phenylphosphinate can be mentioned. These are preferable from the viewpoint of curing at a wavelength of 360 nm or more and 400 nm or less and in terms of compatibility with pigments.

In addition, those having a molecular structure partially common to these but having a high molecular weight can also be used. These photopolymerization initiators are reactive to ultraviolet rays, and when a high-energy light source such as an electron beam, α, β, γ-ray, or X-ray is used, the above-mentioned photopolymerization initiator is used. Although the photopolymerization reaction can be carried out without this, this is generally known from the past, and since the equipment is very expensive, it will not be described in detail in the present invention.
Hereinafter, the "curable composition" is also referred to as an "active energy ray-curable composition".

<Organic solvent>
The active energy ray-curable composition of the present invention may contain an organic solvent, but it is preferable not to contain it if possible. If the composition does not contain an organic solvent, particularly a volatile organic solvent (VOC (Volatile Organic Compounds) free), the safety of the place where the composition is handled is further enhanced, and it is possible to prevent environmental pollution. .. The "organic solvent" means a general non-reactive organic solvent such as ether, ketone, xylene, ethyl acetate, cyclohexanone, and toluene, and should be distinguished from the reactive monomer. be. Further, "not containing" the organic solvent means that it is substantially free of the organic solvent, and it is preferably less than 0.1% by mass.

(Polymerization inhibitor)
A polymerization inhibitor can be added to the curable composition of the present invention, if necessary.
Polymerization inhibitors include 4-methoxy-1-naphthol, methylhydroquinone, hydroquinone, t-butylhydroquinone, di-t-butylhydroquinone, methquinone, 2,2'-dihydroxy-3,3'-di (α-methyl). Cyclohexyl) -5,5'-dimethyldiphenylmethane, p-benzoquinone, di-t-butyldiphenylamine, 9,10-di-n-butoxycyantrasen, 4,4'-[1,10-dioxo-1,10- Decandylbis (oxy)] bis [2,2,6,6-tetramethyl] -1-piperidinyloxy and the like can be mentioned.

(Surfactant)
A surfactant can be added to the curable composition of the present invention, if necessary.
Examples of the surfactant include polyether, amino group, carboxyl group, higher fatty acid ester having a hydroxyl group, polyether, amino group, carboxyl group at the side chain or the terminal, polydimethylsiloxane compound having a hydroxyl group, polyether, amino group, and the like. Examples thereof include fluoroalkyl compounds having a carboxyl group and a hydroxyl group.

<Composition container>
The composition container of the present invention means a container in which an active energy ray-curable composition is stored, and is suitable for use in the above-mentioned applications. For example, when the active energy ray-curable composition of the present invention is used for ink, the container containing the ink can be used as an ink cartridge or an ink bottle, whereby ink transfer, ink replacement, etc. It is not necessary to touch the ink directly in the work, and it is possible to prevent the fingers and clothes from getting dirty. In addition, it is possible to prevent foreign substances such as dust from being mixed into the ink. Further, the shape, size, material, etc. of the container itself may be suitable for the intended use and usage, and is not particularly limited, but the material is a light-shielding material that does not transmit light, or the container blocks light. It is desirable that it is covered with a sex sheet or the like.

<Image formation method, forming device>
The method for forming an image of the present invention includes, at least, an irradiation step of irradiating an active energy ray to cure the active energy ray-curable composition of the present invention, and the image forming apparatus of the present invention has an active energy. An irradiation means for irradiating the rays and an accommodating portion for accommodating the active energy ray-curable composition of the present invention may be provided, and the container may be accommodated in the accommodating portion. Further, it may have a discharge step and a discharge means for discharging the active energy ray-curable composition. The method of discharging is not particularly limited, and examples thereof include a continuous injection type and an on-demand type. Examples of the on-demand type include a piezo method, a thermal method, and an electrostatic method.
FIG. 1 is an example of an image forming apparatus provided with an inkjet ejection means. Ink is ejected to the recorded medium 22 supplied from the supply roll 21 by each color printing unit 23a, 23b, 23c, 23d provided with an ink cartridge for each color active energy ray-curable ink of yellow, magenta, cyan, and black and an ejection head. Will be done. Then, the light sources 24a, 24b, 24c, and 24d for curing the ink are irradiated with active energy rays to cure the ink, and a color image is formed. After that, the recording medium 22 is conveyed to the processing unit 25 and the printed matter take-up roll 26. Each printing unit 23a, 23b, 23c, 23d may be provided with a heating mechanism so that the ink is liquefied at the ink ejection portion. Further, if necessary, a mechanism for cooling the recording medium to about room temperature by contact or non-contact may be provided. Further, as the inkjet recording method, a serial method in which the head is moved to eject ink onto the recording medium or a recording medium is continuously moved with respect to a recording medium that moves intermittently according to the ejection head width. Any of the line methods of ejecting ink onto the recording medium from the head held at a fixed position can be applied.
The recording medium 22 is not particularly limited, and examples thereof include paper, film, metal, and composite materials thereof, and may be in the form of a sheet. Further, the configuration may be such that only single-sided printing is possible or double-sided printing is possible.
Further, the activation of the active energy rays from the light sources 24a, 24b, and 24c may be weakened or omitted, and after printing a plurality of colors, the activation energy rays may be irradiated from the light source 24d. This makes it possible to save energy and reduce costs.
The recorded materials recorded by the ink of the present invention include not only those printed on a smooth surface such as ordinary paper or resin film, but also those printed on a surface to be printed having irregularities, metal, ceramics, and the like. It also includes those printed on the printed surface made of various materials. Further, by stacking two-dimensional images, it is possible to form a partially three-dimensional image (an image composed of two-dimensional and three-dimensional) or a three-dimensional object.
FIG. 2 is a schematic view showing an example of another image forming apparatus (three-dimensional stereoscopic image forming apparatus) according to the present invention. The image forming apparatus 39 of FIG. 2 uses a head unit (movable in the AB direction) in which inkjet heads are arranged to discharge the first active energy ray-curable composition from the discharge head unit 30 for a modeled object for a support. The second active energy ray-curable composition having a composition different from that of the first active energy ray-curable composition is discharged from the head units 31 and 32, and each of these compositions is cured by the adjacent ultraviolet irradiation means 33 and 34. It is laminated while being laminated. More specifically, for example, the second active energy ray-curable composition is discharged from the support discharge head units 31 and 32 onto the modeled object support substrate 37, and is irradiated with the active energy rays to be solidified. After forming the first support layer having the reservoir portion, the first active energy ray-curable composition is discharged from the discharge head unit 30 for a modeled object to the reservoir portion, and is irradiated with the active energy ray to be solidified. By repeating the process of forming the first modeled object layer a plurality of times while lowering the vertically movable stage 38 according to the number of layers, the support layer and the modeled object layer are laminated to form the three-dimensional model 35. To make. After that, the support laminated portion 36 is removed as needed. In FIG. 2, only one discharge head unit 30 for a modeled object is provided, but two or more may be provided.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the following description, "parts" and "%" indicate "parts by mass" and "% by mass" unless otherwise specified.

[Preparation of pigment dispersion]
(Pigment dispersion liquid 1)
As the yellow pigment, Pigment Yellow 155, which is a Graphtol Yellow 3GP manufactured by Clariant AG, was used.
A pre-dispersion solution was prepared by stirring and mixing 15 parts of this red pigment, 8 parts by weight of the pigment dispersant Solsperse 32000 manufactured by Lubrizol, 1 part of Solsperse 22000, and 76 parts of the reagent phenoxyethyl acrylate manufactured by Tokyo Kasei. Next, 240 mL of zirconia beads having a diameter of 0.5 mm was filled in a 300 mL container of a bead mill DynoMillMultilabo manufactured by Simmal Enterprise Co., Ltd. as a bulk volume, and the balance was filled in the container with the pre-dispersion liquid to a peripheral speed of 8 m / s for the stirring blade. After the dispersion treatment for 30 minutes, the pigment dispersion liquid 1 was prepared by pressure filtration with a filter having a pore size of 3 microns.

(Pigment dispersion liquid 2)
A pigment dispersion 2 was prepared in the same manner as the pigment dispersion 1 except that Pigment Yellow 12, which is a disazo yellow manufactured by Dainichiseika Co., Ltd., was used as the yellow pigment.

(Pigment dispersion liquid 3)
A pigment dispersion 3 was prepared in the same manner as the pigment dispersion 1 except that Pigment Yellow 13, which is a disazo yellow manufactured by Dainichiseika Co., Ltd., was used as the yellow pigment.

(Pigment dispersion liquid 4)
The pigment dispersion liquid 4 was prepared in the same manner as in the preparation of the pigment dispersion liquid 1 except that Pigment Yellow 83, which is a disazo yellow manufactured by Dainichiseika Co., Ltd., was used as the yellow pigment.
All of the pigment dispersions had good dispersibility with a 90% integrated average particle size of 150 to 300 nm measured by a particle size distribution meter UPA-EX150 manufactured by Nikkiso Co., Ltd.

(Making yellow ink)
After the pigment dispersions 1 to 4 obtained above and the following materials (A) to (C) are stirred and mixed at the blending ratios shown in Table 1 (numerical values are parts by mass) to uniformly dissolve the dissolved components. The inks of Examples 1 to 11 and Comparative Examples 1 and 2 were obtained by filtering with a filter having a pore size of 1 micron.
(A) Monomer (B) Photoinitiator and sensitizer (C) Polymerization inhibitor The details of A1 to A8, B1 to B6, and C1 in Table 1 are as follows.

(monomer)
A1: 2-Phenoxyethyl Acrylate Tokyo Kasei Reagent A2: Tetrahydrofurfuryl Acrylate Tokyo Kasei Reagent A3: Isobornyl Acrylate Tokyo Kasei Reagent A4: Vinyloxyethoxyethyl Acrylate Nippon Catalyst "VEEA"
A5: Isodecylacrylate Tokyo Kasei Reagent A6: N-vinyl caprolactam Tokyo Kasei Reagent A7: Tripropylene glycol diacrylate Tokyo Kasei Reagent A8: Trimethylolpropane Triacrylate Tokyo Kasei Reagent

(Photopolymerization initiator)
B1: 2,4,6-trimethylbenzoyldiphenylphosphine oxide [IMM's "Omnirad TPO" solid at 23 ° C (powder)]
B2: Ethyl 2,4,6-trimethylbenzoylphenylphosphinate IGM "Omnirad TPO-L" Liquid (yellow liquid) at 23 ° C.
B3: Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide [IGM "Omnirad 819" solid at 23 ° C (powder)]
B4: Polyethylene glycol (200) di (β-4 [4- (2-dimethylamino-2-benzyl) butanonylphenyl] piperazine) propionate [IGM "Omnipol 910" liquid at 23 ° C (yellow viscous liquid) ]
(Sensitizer)
B5: 2- (2- (1- (2-((2- (9-oxothioxanthene-2-yl) oxyacetyl) amino) -3- (1- (2- (2-propenoyloxyethoxy)) Ethoxy) ethoxy) -2- (1- (2- (2-propenoiroxyethoxy) ethoxy) ethoxymethyl) propoxy) ethoxy) ethoxy) ethyl propenoate [IGM "Omnipol3TX" liquid (yellow) at 23 ° C. liquid)]
B6: 2,4-diethylthioxanthone [Tokyo Kasei Reagent Solid at 23 ° C (powder)]
(Polymerization inhibitor)
C1: p-Methoxyphenol (commonly known as MEHQ) Tokyo Kasei Reagent

The following evaluations were performed for each of the inks of Examples and Comparative Examples.
The evaluation results of each ink are shown in Table 2.

[Image formation]
First, regarding the handling of ink, the ink is sealed in an aluminum pouch bag having the shape shown in FIG. 1 so that air bubbles do not enter, and the pouch bag in which the ink is sealed is stored in a plastic cartridge as shown in FIG. Then, an ink flow path was installed from the cartridge to the MH5420 head manufactured by Ricoh in a housing in which the cartridge could be stored, and an ink jet was ejected to produce a solid image of 3 cm × 10 cm. The amount of ink droplets injected was adjusted so that the coating thickness was about 15 microns.

It is desirable that the physical characteristics of the ink meet the required specifications of the inkjet ejection head to be used. Various ejection heads are commercially available from many manufacturers, and some of them have a large ejection force that can handle high-viscosity inks and some have a wide range of temperature control functions. In view of such a situation, the viscosity of the ink is preferably 2 to 150 mPa · s at 25 ° C, and more preferably 5 to 18 mPa · s in consideration of ejection at 25 ° C. However, it is also possible to use the temperature control function of the ejection head as described above, and if the viscosity is too high at 25 ° C, the head may be heated as necessary to reduce the viscosity of the ink. Well, assuming this, if the heating condition is 60 ° C., the viscosity at 60 ° C. is preferably 2 to 20 mPa · s, and more preferably 5 to 18 mPa · s. However, from the viewpoint of energy saving and shortening of operation preparation time, it is more desirable to be able to discharge at a lower temperature. In Comparative Examples and Examples, the ink viscosity was 8 to 15 mPa · s at an ejection temperature of 30 to 60 ° C.

[Evaluation of curability]
(Evaluation method)
A commercially available polyethylene terephthalate film (Toyobo Cosmo Shine / thickness 188 microns) is used as a general-purpose film material for the base material on which an image is formed by ink, and the film is ejected by inkjet to a thickness of about 15 microns. A solid image was created and irradiated with a predetermined illuminance and integrated light amount using a high-pressure mercury lamp (Light Hammer 6 manufactured by Heleus) or an LED (manufactured by Heleus) that emits light at 360 nm or more and 400 nm or less as a light source. The irradiation conditions (illuminance and integrated light intensity) were set to the following two types, A and B.
Irradiation condition A: 3W / cm ² , 3J / cm ²
Irradiation condition B: 3W / cm ² , 1J / cm ²
(Evaluation criteria)
When the coating film was touched to a non-adhesive state, it was judged to be "cured". Those that were uncured or semi-cured were judged to be "uncured".

[Evaluation of image density]
For the red density of the solid image obtained above, the OD value was measured by a spectrophotometer 962 manufactured by XRITE, with an image-formed film placed on 50 sheets of Ricoh PPC paper "My Paper".

[Evaluation of dischargeability]
As for the ejection property, the ink-like flight state when the Ricoh MH5420 head is driven at a predetermined frequency is observed with a high-speed camera continuously for 1 minute for 320 nozzles in a row at the end, and the above-mentioned non-ejection, bending, and speed are observed. The number of nozzles with ejection problems such as abnormalities was counted. Cold-resistant dissolution stability is as follows: A 13 mL brown bottle sealed with ink is stored in a freezer set at -30 ° C for 10 days, and then immediately taken out, the ink is filtered with a Teflon® membrane filter having a pore size of 10 microns and placed on the filter. When the remaining solid residue was not visible, it was marked with ◯, and when the solid residue was visible, it was marked with x.

When cured with a light source that emits light at a wavelength of 360 nm or more and 400 nm or less from Examples 1, 4 and 5 and Comparative Example 1, by using the red pigment represented by the structural formula, it is equivalent to or equivalent to that of Comparative Example. It was found that an image density higher than that and a better ejection property than the comparative example could be obtained.
In Examples 2 to 3, it was found that the ejection property can be further improved by further reducing the pigment blending ratio. However, from Example 3 and Comparative Example 2, the ejection property was sufficiently good at the time of the pigment compounding ratio of 0.5%, and further reduction of the pigment compounding ratio only brought about a decrease in the image density, and no advantage was found.
As in Example 6, the curability can be further improved by increasing the compounding ratio of the polymerization initiator. However, since the stability against cold dissolution is lowered, it may be used with consideration such as avoiding use in cold regions.
By using a room temperature liquid initiator as in Examples 7 and 8, both improvement in curability and cold dissolution stability can be achieved, and ethyl 2,4,6-trimethylbenzoylphenylphosphinate as in Example 8 can be achieved. It is even more desirable to use. As in Examples 9 to 11, it was found that the same applies when the compounding ratios and types of the monomers and initiators used or used in combination are different or when the polymerization inhibitor is not contained, and thus it is appropriately appropriate depending on the application. All you have to do is select the material.

1 Storage pool (accommodation)
3 Movable stage 4 Active energy ray 5 Active energy ray Curing type composition 6 Curing layer 21 Supply roll 22 Recording medium 23a, 23b, 23c, 23d Printing unit 24a, 24b, 24c, 24d Light source 25 Processing unit 26 Printed matter take-up roll 30 Discharge head unit 31, 32 for modeled object Discharge head unit 33, 34 for support UV irradiation means 35 Three-dimensional model 36 Support laminated part 37 Modeled object support substrate 38 Stage 39 Image forming device

Special Table 2004-526820 Gazette

Claims (11)

The polymerizable compound and a pigment having a chemical structure represented by the following structural formula (1) are contained in an amount of 1% by mass or more and 3% by mass or less, and a photopolymerization initiator having absorption at a wavelength of 360 nm or more and 400 nm or less.
The polymerizable compound contains 2-phenoxyethyl acrylate or trimethylolpropane triacrylate and tripropylene glycol diacrylate.
The photopolymerization initiator is ethyl 2,4,6-trimethylbenzoylphenylphosphinate.
A curable composition characterized by this .

The curable composition according to claim 1, wherein the content of the polymerizable compound in the curable composition is 66.4% by mass, and the content of the photopolymerization initiator is 13% by mass. The curable composition according to claim 1 or 2, wherein the photopolymerization initiator is liquid at 23 ° C. A curable ink comprising the curable composition according to any one of claims 1 to 3 . The curable ink according to claim 4 , which is an inkjet ink. A composition storage container containing the curable composition or curable ink according to any one of claims 1 to 5 . The step of ejecting the curable composition or the curable ink according to any one of claims 1 to 5 , and the step of irradiating the ejected curable composition or the curable ink with light having a wavelength of 360 nm or more and 400 nm or less. A method for producing a two-dimensional or three-dimensional cured product including. The method for producing a two-dimensional or three-dimensional cured product according to claim 7 , wherein the ejection step is a ejection step of ejecting by an inkjet recording method. The composition accommodating container according to claim 6 , the means for ejecting the curable composition or curable ink contained in the composition accommodating container, and the ejected curable composition or curable ink having a wavelength of 360 nm or more. A two-dimensional or three-dimensional image forming apparatus comprising a means for irradiating light having a wavelength of 400 nm or less. The two-dimensional or three-dimensional image forming apparatus according to claim 9 , wherein the ejection means ejects a curable composition or a curable ink by an inkjet recording method. The cured composition of the curable composition or the cured product of the curable ink according to any one of claims 1 to 5 .

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