Curable composition for inkjet

Abstract

[Question] To provide a curable composition suitable for inkjet processing that cures at practical exposure levels, exhibits high hardness in the cured film, suppresses glossiness in black matrices used in LED products, and further exhibits a matte effect. [Solution] A curable composition comprising: (A) a polyfunctional alicyclic epoxy compound, (B) an oxetane compound, (C) a cyclic siloxane compound having four or more epoxy groups, and (D) a photocationic polymerization initiator, wherein the cured coating film has an OD value of 4 or greater at a film thickness of 10 to 20 μm.

Description

Technical Field

[0001] The present invention relates to a curable composition, and in particular to a curable composition for inkjet printing and a cured product thereof. Background Art

[0002] In recent years, LED displays using mini-LEDs, which are slightly larger than micro-LEDs and have a side size of approximately several hundred μm, have been gradually put into practical use.

[0003] In order to make the colors displayed by LED products more clearly visible, LED displays use a technique in which a black ink composition is applied to the gaps (approximately 200 μm) between LEDs after mounting on a substrate, thereby forming a so-called black matrix.

[0004] As such a technology, for example, Patent Document 1 proposes a technology in which a black matrix is ​​formed by using a resin composition for a light-shielding layer containing a black pigment such as carbon black, a dispersant, and a thermosetting binder, without patterning using photolithography.

[0005] On the other hand, since a large number of LEDs are mounted, it is desirable to apply the black ink composition by inkjet printing from the viewpoint of production efficiency.

[0006] Inkjet printing involves using an inkjet printer to eject droplets of a curable composition onto a substrate, followed by irradiation with active energy rays such as UV rays for immediate curing. Furthermore, inkjet printing allows for direct depiction of a predetermined print pattern from digital data, reducing ink usage and eliminating the need for a screen printing plate. This allows for more efficient production compared to existing methods. Furthermore, because inkjet printing is non-contact, it can easily print on uneven or flexible substrates, making it promising for use in printed circuit board materials.

[0007] As such a curable composition for inkjet, in order to enable stable inkjet discharge at room temperature and to form a cured film having sufficient heat resistance and insulation properties by light irradiation alone without heating, for example, Patent Document 2 proposes the following technology: containing specific monofunctional polymerizable monomers and polyfunctional polymerizable monomers.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-164457

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-143982 Summary of the Invention

[0012] Problems to be solved by the invention

[0013] Here, even if it is a black matrix, it will reflect light and emit a glossy property, which can be said to have a concern of damaging the color of the LED, so it is not preferred. Therefore, it is considered to contain a matte material in the composition forming the black matrix to suppress the gloss of the cured product.

[0014] However, since the matte material is large in size due to its use, when it is contained in the composition, there is a concern that it may prevent the composition from being smoothly discharged from the inkjet nozzle.

[0015] Similarly, from the viewpoint of smooth discharge, it is desirable to suppress the viscosity of the composition to be used.

[0016] In this regard, the technology described in Patent Document 1 does not even disclose a solution for simultaneously solving these problems.

[0017] On the other hand, the active energy ray dose for curing the curable composition for inkjet is suppressed to approximately 2000 mJ / cm 2 Furthermore, it is desirable that the hardness of the cured product and the adhesion of the cured product to the substrate be as excellent as possible.

[0018] However, the technology described in Patent Document 2 does not envision a curable composition that can be cured with a practical exposure dose and provide a cured product having a higher hardness.

[0019] In view of the above, an object of the present invention is to provide a curable composition suitable for inkjet printing, which can form a cured product (e.g., a cured film) that can be cured with a practical exposure dose and has high hardness and suppressed gloss as a black matrix for LED products.

[0020] Solutions for solving problems

[0021] The present inventors have conducted intensive studies and have primarily found that the above-mentioned problems can be solved by using a composition containing a specific polyfunctional alicyclic epoxy compound, an oxetane compound, and a cyclic siloxane compound having four or more epoxy groups, thereby completing the present invention.

[0022] That is, the present invention relates to a curable composition characterized by containing:

[0023] (A) a polyfunctional alicyclic epoxy compound,

[0024] (B) oxetane compounds,

[0025] (C) a cyclic siloxane compound having 4 or more epoxy groups,

[0026] (D) a photocationic polymerization initiator,

[0027] Furthermore, the OD value of the cured coating film at a film thickness of 10 to 20 μm is 4 or more.

[0028] Among them, a preferred embodiment is the curable composition having a viscosity of 5 to 20 mPa·s at 50°C.

[0029] In another preferred embodiment, the curable composition has a 60-degree specular glossiness of 60 or less on the surface of the coating film after curing.

[0030] In another preferred embodiment, the curable composition has an arithmetic mean surface roughness (Ra) of the coating film surface after curing of 0.3 to 3.0 μm.

[0031] A more preferred embodiment is the curable composition further comprising (E) a photocationic sensitizer.

[0032] A particularly preferred embodiment is the curable composition comprising carbon black as a colorant in an amount within a range of 3.0% by mass to 25.0% by mass relative to the mass of the total solid content of the curable composition.

[0033] Another embodiment also relates to a cured product obtained from the above-mentioned curable composition.

[0034] Another embodiment of the present invention relates to a curable composition comprising:

[0035] (A) a polyfunctional alicyclic epoxy compound,

[0036] (B) oxetane compounds,

[0037] (C) a cyclic siloxane compound having 4 or more epoxy groups,

[0038] (D) a photocationic polymerization initiator, and

[0039] (E) Photocationic sensitizer.

[0040] The curable composition preferably has a viscosity of 5 to 20 mPa·s at 50°C.

[0041] Furthermore, it is preferred that the curable composition can emit 2000 mJ / m at a wavelength of 395 nm. 2 exposure to cure.

[0042] In the curable composition, the photocationic sensitizer (E) is preferably an alkoxyanthracene sensitizer.

[0043] Furthermore, the present invention also relates to a cured product obtained from these curable compositions.

[0044] Effects of the Invention

[0045] The present invention can provide a curable composition having a low viscosity and curable at a practical exposure dose, and a cured product of the curable composition having high hardness, high OD value, and low gloss.

[0046] Therefore, the curable composition of the present invention is expected to be suitably used as a material for inkjet printing for forming a matte cured coating film serving as a black matrix of an LED product, for example. DETAILED DESCRIPTION

[0047] The curable composition of the present invention mainly contains components having different curing speeds or curing shrinkages, such as (A) a polyfunctional alicyclic epoxy compound, (B) an oxetane compound, and (C) a cyclic siloxane compound having four or more epoxy groups.

[0048] When the (A) polyfunctional alicyclic epoxy compound generates an acid through light irradiation, the (D) photocationic polymerization initiator initiates ring-opening polymerization of the epoxy group more rapidly than the (B) oxetane compound, leading to curing and shrinkage. Similarly to the (A) component, the (C) cyclic siloxane compound having four or more epoxy groups also shrinks more rapidly upon curing than the (B) oxetane compound.

[0049] In contrast, the oxetane compound (B) has a four-membered ring structure and therefore exhibits less volume shrinkage during curing after light irradiation than the epoxy compound. Furthermore, the curing start time is also slower. Therefore, it is speculated that these differences may be the factor that allows the formation of so-called wrinkles or folds on the coating film surface after curing.

[0050] Furthermore, the curable composition of the present invention has such a high blackness that the OD value of the cured coating film at a film thickness of 10 to 20 μm is 4 or higher, and has a low light transmittance. Therefore, light does not easily penetrate deep into the coating film during light irradiation, and differences in the curing speed of the various components during light irradiation are likely to occur. This is presumably a factor in the formation of so-called wrinkles or folds on the surface of the cured coating film.

[0051] As described above, when the curable composition of the present invention is cured according to its composition, the surface of the coating film is not completely smooth, but forms shapes such as so-called wrinkles and folds. It is believed that this can diffuse various light from the outside and exert the same effect as matte, thereby forming a good matte (rough) cured coating film with low gloss.

[0052] From the viewpoint of suppressing light reflection as a black matrix material used in LED products, the curable composition of the present invention is characterized in that the OD value of the cured coating film at a film thickness of 10 to 20 μm is 4 or more, preferably 5 or more.

[0053] The OD value can be calculated based on the formula: OD value = -log10 (T / 100) by measuring the amount of light transmitted using a transmission densitometer (model: X-Rite 361T; light source wavelength 400 to 800 nm; manufactured by Sakata Inx Engineering Corporation).

[0054] Furthermore, from the viewpoint of roughening the cured product (cured coating film) of the curable composition of the present invention, the surface of the cured product (cured coating film) preferably exhibits a value of 60 or less, more preferably 35 or less, measured at a 60-degree specular gloss meter according to ASTM D 523-89 or ISO 2813, based on a film thickness of 10 μm of the cured coating film.

[0055] Furthermore, for the curable composition of the present invention, the arithmetic mean surface roughness (Ra) of the cured product (cured coating film) is preferably 0.3 to 3.0 μm from the viewpoint of balancing the roughening of the surface of the cured product (cured coating film) and the OD value. When the arithmetic mean surface roughness (Ra) of the cured product (cured coating film) is within this range, the OD value of the cured coating film at a film thickness of 10 to 20 μm and the 60-degree specular gloss of the cured product (cured coating film) surface according to ASTM D 523-89 or ISO 2813 will each be within the above range.

[0056] Furthermore, the curable composition of the present invention is generally intended to be suitable for inkjet processing. Therefore, from the perspective of smooth discharge from an inkjet nozzle, its viscosity is preferably in the range of 5 to 20 mPa·s at 50°C, and more preferably in the range of 5 to 15 mPa·s at 50°C.

[0057] The viscosity can be measured using, for example, a cone-plate viscometer (TVE-33H manufactured by Toki Sangyo Co., Ltd.).

[0058] Furthermore, the curable composition of the present invention comprises (A) a polyfunctional alicyclic epoxy compound, (B) an oxetane compound, (C) a cyclic siloxane compound having four or more epoxy groups, (D) a photocationic polymerization initiator, and (E) a photocationic sensitizer. The resulting cured product not only has higher hardness and adhesion, but also can generate a high-efficiency polymer at a wavelength of approximately 395 nm at a rate of approximately 2000 mJ / m². 2 exposure to cure.

[0059] Hereinafter, each component of the curable composition of the present invention having the above-mentioned characteristics will be described.

[0060] [(A) Polyfunctional alicyclic epoxy compound]

[0061] In the present invention, by incorporating the (A) polyfunctional alicyclic epoxy compound into the curable composition, the hardness of a cured product obtained from the curable composition can be increased.

[0062] In the present invention, the (A) polyfunctional alicyclic epoxy compound is a compound having a total of two or more oxirane groups represented by the following structural formula and / or cyclohexyl oxide groups represented by the following structural formula in the molecule:

[0063]

[0064] Examples of the compound having an oxirane group represented by the above structural formula include compounds having the following structures:

[0065]

[0066] In addition, examples of the compound having an epoxycyclohexyl group represented by the above structural formula include compounds having any of the following structures:

[0067]

[0068]

[0069] (wherein A represents an alkylene group having 1 to 8 carbon atoms; n1 and n2 each represent an integer from 1 to 30).

[0070] As (A) the polyfunctional alicyclic epoxy compound, it is of course possible to use a commercially available product.

[0071] Examples include terpene dioxide (LDO) (manufactured by SYMRISE), CELLOXIDE 2021P, CELLOXIDE 2081, and Epolide GT401 (all manufactured by Daicel Co., Ltd.), Syna Epoxy 06E, Syna Epoxy 21, and Syna Epoxy 28 (all manufactured by SYNASIA), and THI-DE (manufactured by JX Nippon Oil & Energy Corporation).

[0072] From the viewpoint of further improving the hardness of the cured film, it is also preferred to use any one of the compounds of formulae a2 to a10 in combination with the compound represented by formula a1.

[0073] In this case, the mass ratio of the compound represented by formula a1 to any one of the compounds of formulae a2 to a10 is 100:0 to 50:50, preferably 100:0 to 80:20.

[0074] The total content of the (A) polyfunctional alicyclic epoxy compound is 10 to 90% by mass, preferably 30 to 60% by mass, based on the total solid content of the curable composition, from the viewpoint of the hardness of the cured product.

[0075] [(B) Oxetane compound]

[0076] In the curable composition of the present invention, it is believed that by using the components (A) the polyfunctional alicyclic epoxy compound and (B) the oxetane compound in combination, a shape such as so-called wrinkles or folds can be formed in the cured product (cured coating film).

[0077] As the (B) oxetane compound, a monofunctional one or a polyfunctional one can be used.

[0078] Examples of the monofunctional oxetane compound include 3-methyloxetane, 3-ethyloxetane, 3-hydroxymethyloxetane, 3-methyl-3-hydroxymethyloxetane, and 3-ethyl-3-hydroxymethyloxetane.

[0079] In addition, as a polyfunctional oxetane compound, in addition to bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl]ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methyl acrylate, (3-ethyl-3-oxetanyl)methyl acrylate, In addition to polyfunctional oxetanes such as (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxetanyl)methyl methacrylate, and oligomers or copolymers thereof, etherified products of oxetane alcohol and resins having a hydroxyl group such as novolac resin, poly(p-hydroxystyrene), Cardo-type bisphenols, calixarenes, calixresorcinarene, or silsesquioxane can be mentioned. In addition, copolymers of unsaturated monomers having an oxetane ring and alkyl (meth)acrylates can be mentioned.

[0080] As the (B) oxetane compound, for example, OXT-101 and OXT-221 (both manufactured by Toagosei Co., Ltd.) or the following formula:

[0081]

[0082] The TR-TCM-207 (manufactured by TRONLY Co., Ltd.) shown below is a commercially available product.

[0083] Among them, from the viewpoint of being able to better suppress the glossiness of the cured product, a polyfunctional one is preferred over a monofunctional one.

[0084] However, it is of course possible to use a monofunctional compound and a polyfunctional compound in combination.

[0085] The content of the oxetane compound (B) is 5 to 70% by mass, preferably 10 to 50% by mass, based on the total solid content of the curable composition, from the viewpoint of hardness and glossiness of the cured product.

[0086] [(C) Cyclic siloxane compound having 4 or more epoxy groups]

[0087] The curable composition of the present invention contains (C) a cyclic siloxane compound having four or more epoxy groups, thereby improving the adhesion between the cured product (cured coating film) and the substrate.

[0088] Such a cyclic siloxane compound (C) having 4 or more epoxy groups has a siloxane bond-based structure:

[0089] -Si-O-Si-

[0090] The cyclic structure may include a tetramer, a pentamer, or a polymer thereof. Furthermore, four or more epoxy groups are bonded to a chain extending from each Si atom of the cyclic siloxane structure.

[0091] Examples of these include those having structures represented by the following formulae (1), (2), and (3) (corresponding to a tetramer, a pentamer, and a hexamer, respectively).

[0092]

[0093] (Where R 1 、R 3 、R 5 and R 7 is an epoxy group, R 2 、R 4 、R 6 and R 8 Each is independently a hydrocarbon group, preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group or an ethyl group.)

[0094]

[0095] (Where R 1 、R 3 、R 5 、R7 and R 9 4 or 5 of them are all epoxy-containing groups, and there are non-epoxy-containing groups R 1 、R 3 、R 5 、R 7 or R 9 In the case of , it is a hydrocarbon group, preferably an alkyl group having 1 to 3 carbon atoms, R 2 、R 4 、R 6 、R 8 and R 10 Each is independently a hydrocarbon group, preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group or an ethyl group.)

[0096]

[0097] (Where R 1 、R 3 、R 5 、R 7 、R 9 and R 11 4, 5 or 6 of them are all epoxy-containing groups, and there are R 1 、R 3 、R 5 、R 7 、R 9 or R 11 In the case of , it is a hydrocarbon group, preferably an alkyl group having 1 to 3 carbon atoms, R 2 、R 4 、R 6 、R 8 、R 10 and R 12 Each is independently a hydrocarbon group, preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group or an ethyl group.)

[0098] Examples of the epoxy-containing group include a glycidoxymethyl group, a glycidoxyethyl group, and a glycidoxypropyl group.

[0099] Specific examples of these include those having the following structures.

[0100]

[0101] As the epoxy-containing group, an alicyclic epoxy group is more preferable. Examples of the cyclic siloxane compound (C) having four or more epoxy groups and having such an alicyclic epoxy group include those having the following structure:

[0102]

[0103] As the (C) cyclic siloxane compound having four or more epoxy groups, it is of course possible to use a commercially available product such as KR-470 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0104] Moreover, you may use together 2 or more types of (C) cyclic siloxane compounds which have 4 or more epoxy groups.

[0105] The content of the cyclic siloxane compound (C) having four or more epoxy groups is 1 to 30% by mass, preferably 3.0 to 15% by mass, based on the total solid content of the curable composition, from the viewpoint of hardness and glossiness of the cured product.

[0106] [(D) Photocationic polymerization initiator]

[0107] Examples of the photocationic polymerization initiator include onium salts such as diazonium salts, iodonium salts, bromonium salts, chloroonium salts, sulfonium salts, selenium salts, pyrylium salts, thiapyrylium salts, and pyridinium salts; halogenated compounds such as tris(trihalomethyl)-s-triazine and its derivatives; 2-nitrobenzyl sulfonic acid esters; iminosulfonates; 1-oxo-2-diazonaphthoquinone-4-sulfonate derivatives; N-hydroxyimide=sulfonates; tris(methylsulfonyloxy)benzene derivatives; bissulfonyldiazomethanes; sulfonylcarbonylalkanes; sulfonylcarbonyldiazomethanes; disulfone compounds, and the like.

[0108] These photopolymerization initiators can be used alone or in combination of two or more.

[0109] (D) Commercially available products of the photocationic polymerization initiator include, for example, CPI-100P, CPI-200K, and CPI-101A (all manufactured by San-Apro Ltd.), Cyracure photoinitiator UVI-6990, Cyracure photoinitiator UVI-6992, and Cyracure photoinitiator UVI-6976 (all manufactured by Dow Chemical Japan Co., Ltd.), Adeka Optomer SP-150, Adeka Optomer SP-152, Adeka Optomer SP-170, and Adeka Optomer SP-172 (all manufactured by Asahi Denka Kogyo Co., Ltd.), CI-5102 and CI-2855 (all manufactured by Nippon Soda Co., Ltd.), Sunaid SI-60L, Sunaid SI-80L, Sunaid SI-100L, Sunaid SI-110L, Sunaid SI-180L, and Sunaid SI-110, Sunaid SI-145, Sunaid SI-150, Sunaid SI-160, Sunaid SI-180 (all manufactured by Sanshin Chemical Industry Co., Ltd.), Esacure 1064, Esacure 1187 (all manufactured by Lamberti), OMNICAT 432, OMNICAT 440, OMNICAT 445, OMNICAT 550, OMNICAT 650, OMNICAT BL-550 (manufactured by IGM RESINS LIMITED), IRGACURE 250 (manufactured by BASF Corporation), Rhodosil Photinoinitiator 2074 (manufactured by Rhodorsil Japan Co., Ltd.), WPI-113, WPI-116, WPI-169, WPI-170 (manufactured by Wako Pure Chemical Industries, Ltd.), and the like.

[0110] Among them, CPI-100P, CPI-101A, CPI-200K, and CPI-210S manufactured by San-Apro Ltd., IRGACURE 250 manufactured by BASF Corporation, and WPI-113, WPI-116, WPI-169, and WPI-170 manufactured by Wako Pure Chemical Industries, Ltd. are preferred.

[0111] (D) The content of the photocationic polymerization initiator is 3.5 to 13% by mass, preferably 3.8 to 6% by mass, based on the total solid content of the curable composition.

[0112] The content of the photocationic polymerization initiator (D) is preferably 4.1 to 12% by mass, more preferably 4.3 to 7.5% by mass, based on the total solid content of the (A) polyfunctional alicyclic epoxy compound, the (B) oxetane compound, and the (C) cyclic siloxane compound having four or more epoxy groups in the curable composition.

[0113] [(E) Photocationic sensitizer]

[0114] In order to further improve the photosensitivity, the curable composition of the present invention may further contain (E) a photocationic sensitizer.

[0115] The (E) photocation sensitizer is preferably a compound that becomes excited by light having a wavelength of 350 nm to 450 nm. Examples include polycyclic aromatic compounds such as pyrene, perylene, benzo[9,10]phenanthrene, and anthracene; xanthenes such as fluorescein, eosin, erythromycin, rhodamine B, and rose bengal; xanthenes such as xanthene, thioxanthone, dimethylthioxanthone, and diethylthioxanthone; cyanines such as thiocarbocyanine and oxacarbocyanine; merocyanines such as merocyanine and carbomerocyanine; rhodanines; oxonols; thiazines such as thionine, methylene blue, and toluidine blue; acridines such as acridine orange, chloroflavin, and acridine yellow; acridones such as acridone and 10-butyl-2-chloroacridone; anthraquinones; squaryliums; styrenes; basic styrenes; and coumarins such as 7-diethylamino-4-methylcoumarin. Among these, anthracene compounds are preferred, alkoxyanthracenes are more preferred, and those having the following structure are particularly preferred:

[0116]

[0117] These (E) photocation sensitizers may be used in combination of two or more types.

[0118] As the (E) photocation sensitizer, commercially available products may be used. Examples thereof include ANTHRACURE (registered trademark) UVS-1101 (diethoxyanthracene; manufactured by Kawasaki Chemicals, Ltd.), ANTHRACURE (registered trademark) UVS-1221 (dipropoxyanthracene; manufactured by Kawasaki Chemicals, Ltd.), and ANTHRACURE (registered trademark) UVS-1331 (dibutoxyanthracene; manufactured by Kawasaki Chemicals, Ltd.).

[0119] (E) Content of the photocationic sensitizer is 0.1-2.0 mass parts with respect to 1 mass part of (D) photocationic polymerization initiator, Preferably it is 0.2-1.0 mass part%.

[0120] The content of the photocationic sensitizer (E) is preferably greater than 0 and less than 6% by mass, and more preferably greater than 1.0% by mass and less than 3.0% by mass, based on the total solid content of the (A) polyfunctional alicyclic epoxy compound, the (B) oxetane compound, and the (C) cyclic siloxane compound having four or more epoxy groups in the curable composition.

[0121] [Colorant]

[0122] From the perspective of black matrix properties, the curable composition of the present invention generally contains a colorant. Typically, a black colorant such as carbon black is used. However, as long as the OD value of the cured product is 4 or higher at a film thickness of 10 μm to 20 μm, and particularly 4 or higher at a thinner film thickness of 10 μm, it is sufficient. Other colorants may be contained in place of the black colorant or may be added to carbon black.

[0123] Examples of black colorants include, in addition to carbon black, inorganic pigments such as ferrosoferric oxide (Fe 3 O 4 ), black titanium oxide, copper manganese black, copper chrome black, and cobalt black, and organic pigments such as cyanine black and aniline black.

[0124] In addition, examples of other colorants include well-known and commonly used red, blue, green, and yellow pigments or dyes.

[0125] The content of the colorant in the curable composition of the present invention can be adjusted in consideration of the OD value and / or glossiness of the cured product, and is generally 3.0 to 25.0% by mass, preferably 4.0 to 15.0% by mass, based on the total solid content of the curable composition.

[0126] [Other ingredients]

[0127] Furthermore, the curable composition of the present invention may further contain other components such as solvents, dispersants, thickeners, surfactants, antioxidants, plasticizers, flame retardants, antistatic agents, leveling agents, defoaming agents, and antibacterial agents within a range that does not impair its properties.

[0128] [Cured Material and Method for Producing the Same]

[0129] The curable composition of the present invention is applied to a target portion of a substrate according to an inkjet process and then cured to form a cured product.

[0130] Curing can be performed by irradiating the applied composition with active energy rays.

[0131] Suitable sources of active energy rays include LEDs, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, and metal halide lamps. Furthermore, electron beams, α-rays, β-rays, γ-rays, X-rays, and neutron beams may also be used. It should be noted that the number of light sources may be one or more. When there are more than two light sources, light sources of different wavelengths may be used in combination.

[0132] The exposure dose of active energy rays is usually 10 to 10,000 mJ / cm 2 , preferably 20 to 2000 mJ / cm 2 More preferably, it is 100 to 2000 mJ / cm 2 within the range.

[0133] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is of course not limited to the following Examples.

[0134] In addition, unless otherwise specified, "parts" and "%" are expressed on a mass basis.

[0135] Example

[0136] The materials were blended according to the amounts listed in Table 1 below and premixed in a stirrer to prepare curable compositions of Examples 1 to 9 and Comparative Examples 1 to 3. The values ​​of the amounts listed in the tables represent parts by mass of the solid content unless otherwise specified.

[0137] [Table 1]

[0138] Table 1. Composition of curable composition (Part 1)

[0139]

[0140] ※1: CELLOXIDE 2021P (manufactured by Daicel Co., Ltd.)

[0141] ※2: LDO (made by SYMRISE)

[0142] ※3: OXT-101 (manufactured by Toagosei Co., Ltd.)

[0143] ※4: OXT-221 (manufactured by Toagosei Co., Ltd.)

[0144] ※5: KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0145] ※6: BYK-315N (manufactured by BYK Japan Co., Ltd.)

[0146] ※7: Pigment black7

[0147] ※8: KR-470 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0148] ※9: CPI-100P (solid content 50%) (made by San-Apro Ltd.)

[0149] ※10: UVS-1101 (manufactured by Kawasaki Chemical Industries, Ltd.)

[0150] Cured products (cured coating films) having a film thickness of 10 μm and 20 μm were obtained from the curable compositions of Examples 1 to 9 and Comparative Examples 1 to 3, respectively. The gloss, OD value, and pencil hardness of these cured products were measured as follows. The viscosity of each curable composition at 50°C before curing was also measured.

[0151] [Preparation of test substrate]

[0152] Under the following conditions, the curable compositions of Examples 1 to 9 and Comparative Examples 1 to 3 were drawn onto substrates using an inkjet printer and then UV-cured to prepare test substrates. Note that a glass substrate was used as the substrate.

[0153] ·Based on the drawing conditions of inkjet printers

[0154] Cured film thickness: 10μm or 20μm

[0155] Apparatus: A piezoelectric inkjet printer (Materials Printer DMP-2831 manufactured by Fujifilm Corporation (head temperature 50° C.)) was used.

[0156] UV curing conditions

[0157] LED-UV lamp (FireEdge FE400 manufactured by Phoseon Technology)

[0158] Illumination: 6000mW / cm 2

[0159] Exposure: 1000mJ / cm 2

[0160] Wavelength: 395nm

[0161] [Glossiness]

[0162] The 60-degree glossiness (gloss value) of the surface of each test substrate was measured using Micro-tri-gross (manufactured by BYK Japan Co., Ltd.) The 60-degree glossiness is expressed as an integer by rounding off the average value to one decimal place.

[0163] ○···Glossiness is 60 or less

[0164] ×···Glossiness exceeds 60

[0165] The results are shown in Tables 2 and 3 below.

[0166] [OD value]

[0167] The coated side of the glass substrate was placed on a transmission densitometer (manufactured by Sakata Inx Engineering Corporation, model: X-Rite 361T, light source wavelength: 400 to 800 nm) with the coating facing the measuring device, and the OD value was evaluated.

[0168] ◎···OD value is 6 or above

[0169] OD value is 4 or more and less than 6

[0170] ×···OD value is lower than 4

[0171] The results are shown in Tables 2 and 3 below.

[0172] [Pencil hardness]

[0173] The pencil hardness of the surface of the obtained cured coating film was measured in accordance with JIS K 5600-5-4.

[0174] The results are shown in Tables 2 and 3 below.

[0175] [Viscosity at 50°C]

[0176] The viscosity of the curable compositions of Examples 1 to 9 and Comparative Examples 1 to 3 at an ink temperature of 50° C. and 100 rpm was measured using a cone-plate viscometer (TVE-33H manufactured by Toki Sangyo Co., Ltd.).

[0177] [Arithmetic mean surface roughness (Ra) μm]

[0178] The arithmetic mean surface roughness of the resulting cured coating film was measured using a 50x objective lens with a profile measurement laser microscope (VK-X100) and an observation application (VK-H1VX) manufactured by KEYENCE CORPORATION. The resulting data was used to calculate the arithmetic mean surface roughness (Ra) using an analysis application (VK-H1XA) manufactured by the same company using a calculation formula in accordance with JIS B0601-2001. The measurement area in this case was the entire area, and the cutoff values ​​for both λs and λc were set to zero.

[0179] The results are shown in Tables 2 and 3 below.

[0180] [Table 2]

[0181] Table 2. Test results 1 (film thickness 10 μm)

[0182]

[0183] [Table 3]

[0184] Table 3. Test results 2 (film thickness 20 μm)

[0185]

[0186] Separately, the respective materials were blended according to the blending amounts listed in Table 4 below and premixed in a stirrer to prepare curable compositions of Examples 10 to 25 and Comparative Examples 4 to 6. The numerical values ​​of the blending amounts in the tables represent parts by mass of the solid content unless otherwise specified.

[0187] [Table 4]

[0188] Table 4. Composition of curable composition (Part 2)

[0189]

[0190] ※1: CELLOXIDE 2021P (manufactured by Daicel Co., Ltd.)

[0191] ※2: LDO (made by SYMRISE)

[0192] ※3: THI-DE (manufactured by JX Nippon Oil & Energy Corporation)

[0193] ※4: OXT-101 (manufactured by Toagosei Co., Ltd.)

[0194] ※5: OXT-221 (manufactured by Toagosei Co., Ltd.)

[0195] ※6: TR-TCM-207 (manufactured by TRONLY Co., Ltd.)

[0196] ※7: KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0197] ※8: BYK-315N (manufactured by BYK Japan Co., Ltd.)

[0198] ※9: Pigment black7

[0199] ※10: KR-470 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0200] ※11: X-40-2678 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0201] ※12: CPI-100P (solid content 50%) (made by San-Apro Ltd.)

[0202] ※13: UVS-1331 (manufactured by Kawasaki Chemical Industries, Ltd.)

[0203] ※14: UVS-1101 (manufactured by Kawasaki Chemical Industries, Ltd.)

[0204] Cured products (cured coating films) were obtained from the curable compositions of Examples 10 to 25 and Comparative Examples 4 to 6 obtained in this manner. These cured products were measured for set to touch, pencil hardness, and cross-cutting as described below. The viscosity of each curable composition at 50°C before curing was also measured.

[0205] [Preparation of test substrate]

[0206] Under the following conditions, the curable compositions of Examples 10 to 25 and Comparative Examples 4 to 6 were drawn onto substrates using an inkjet printer and then UV-cured to prepare test substrates. Note that a glass substrate was used as the substrate.

[0207] ·Based on the drawing conditions of inkjet printers

[0208] Film thickness: 10μm

[0209] Apparatus: A piezoelectric inkjet printer (Materials Printer DMP-2831 manufactured by Fujifilm Corporation (head temperature 50° C.)) was used.

[0210] UV curing conditions

[0211] LED-UV lamp (FireEdge FE400 manufactured by Phoseon Technology)

[0212] Exposure: 5000mJ / cm 2 、1000mJ / cm 2 , 2000mJ / cm 2 , 5000mJ / cm 2 、10000mJ / cm 2

[0213] Wavelength: 395nm

[0214] [Dry to touch after UV curing]

[0215] The dryness to touch of the obtained cured coating film was evaluated.

[0216] ○: No marks left even when touched with fingers

[0217] ×: Feels sticky when touched with fingers

[0218] Blank column: Uncured

[0219] The results are shown in Table 5 below.

[0220] [Viscosity at 50°C]

[0221] The viscosity of the curable compositions of Examples 10 to 25 and Comparative Examples 4 to 6 was measured at an ink temperature of 50° C. and 100 rpm using a cone-plate viscometer (TVE-33H manufactured by Toki Sangyo Co., Ltd.).

[0222] [Pencil hardness]

[0223] The pencil hardness of the surface of the obtained cured coating film was measured in accordance with JIS K 5600-5-4. A pencil hardness of H or higher was considered acceptable.

[0224] The results are shown in Table 5 below.

[0225] [Scratch]

[0226] The obtained cured coating film was cut into 25 grids (5×5) with a width of 1 mm in both vertical and horizontal directions according to JIS K 5600-5-6, and the state of the grids was examined. The evaluation criteria are as follows.

[0227] Classification 0: The cut edge is completely smooth and there is no peeling of any mesh.

[0228] Category 1: Minor peeling of the coating occurs at the intersection of the cuts. The affected area is clearly no more than 5% of the cross-cut area.

[0229] Category 2: The coating peels along the cut edges and / or at the intersections. The affected area is clearly more than 5% but not more than 15% of the cut area.

[0230] Category 3: The coating peels off significantly along the cut edge, partially or entirely, and / or individual sections of the mesh peel off partially or entirely. The affected area in the cross-cut area is clearly more than 15% but not more than 35%.

[0231] Category 4: The coating peels off significantly along the cut edge, partially or entirely, and / or the mesh peels off partially or entirely in multiple locations. The affected area in the cross-cut area is clearly more than 35% but not more than 65%.

[0232] Category 5: Larger peeling than Category 4 occurs.

[0233] [Table 5]

[0234] Table 5. Test results 3

[0235]

Claims

1. A curable composition for inkjet, characterized in that The curable composition for inkjet contains, based on the total solid content: 30% by mass to 4980 / 92.30% by mass of (A) a polyfunctional alicyclic epoxy compound, 1500 / 92.30 mass % to 6000 / 137.30 mass % of (B) an oxetane compound, 3% by mass to 1200 / 112.3% by mass of (C) a cyclic siloxane compound having 4 or more epoxy groups, (D) a photocationic polymerization initiator, and 4.0 to 25.0% by mass of carbon black as a colorant, The (B) oxetane compound is a multifunctional oxetane compound, (A) The polyfunctional alicyclic epoxy compound contains: a compound having a structure of formula (a1) as a bifunctional alicyclic epoxy compound having an oxiranyl group and an oxiranyl group, and a compound having a structure of any one of the following formulae (a2) to (a10) as a bifunctional alicyclic epoxy compound having an oxiranyl group, wherein the mass ratio of the compound having a structure of formula (a1) to the compound having a structure of any one of the following formulae (a2) to (a10) is 100:0 to 74:

26. as well as In the formula, A represents an alkylene group having 1 to 8 carbon atoms; n1 and n2 each represent an integer of 1 to 30, and the OD value of the cured coating film at a film thickness of 10 to 20 μm is 4 or more, The 60-degree specular glossiness of the cured coating surface is 35 or less based on a film thickness of 10 μm after the cured coating. The curable composition has a viscosity of 5 to 20 mPa·s at 50° C.

2. The curable composition for inkjet according to claim 1, wherein The arithmetic mean surface roughness of the cured coating film was 0.3 to 3.0 μm. 3 . The curable composition for inkjet according to claim 1 , further comprising (E) a photocationic sensitizer. 4 . A cured product obtained from the curable composition for inkjet according to claim 1 .

5. A curable composition for inkjet, characterized in that The curable composition for inkjet contains, based on the total solid content: 30% by mass to 4980 / 92.30% by mass of (A) a polyfunctional alicyclic epoxy compound, 1500 / 92.30 mass % to 6000 / 137.30 mass % of (B) an oxetane compound, 3% by mass to 1200 / 112.3% by mass of (C) a cyclic siloxane compound having 4 or more epoxy groups, (D) a photocationic polymerization initiator, and (E) a photocationic sensitizer, The (B) oxetane compound is a multifunctional oxetane compound, (A) The polyfunctional alicyclic epoxy compound contains: a compound having a structure of formula (a1) as a bifunctional alicyclic epoxy compound having an oxiranyl group and an oxiranyl group, and a compound having a structure of any one of the following formulae (a2) to (a10) as a bifunctional alicyclic epoxy compound having an oxiranyl group, wherein the mass ratio of the compound having a structure of formula (a1) to the compound having a structure of any one of the following formulae (a2) to (a10) is 100:0 to 74:

26. as well as In the formula, A represents an alkylene group having 1 to 8 carbon atoms; n1 and n2 each represent an integer of 1 to 30, The curable composition has a viscosity of 5 to 20 mPa·s at 50° C.

6. The curable composition for inkjet according to claim 5, which can emit 2000 mJ / m at a wavelength of 395 nm. 2 exposure to cure.

7. The curable composition for inkjet according to claim 5, wherein The (E) photocationic sensitizer is an alkoxyanthracene sensitizer. 8 . A cured product obtained from the curable composition for inkjet according to claim 5 .

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