Thermosetting inkjet ink

Abstract

The present invention addresses the problem of providing a heat-curable composition that demonstrates superior storage stability at high temperature and superior heat-curability of a curing film surface at high temperature and high humidity, as well as a heat-curable inkjet ink that uses said heat-curable composition.　This heat-curable composition includes a blocked isocyanate (A), and is characterized by also including: a compound (B) that has a functional group capable of hydrogen bonding with the blocked isocyanate (A); and a (meth)acryloyl group-including monomer (C) that does not have a functional group capable of reacting with blocked isocyanates, wherein per 100 parts by mass of the (meth)acryloyl group-including monomer (C), the heat-curable composition includes 0.1-20 parts by mass of the compound (B) and 0.1-20 parts by mass of the blocked isocyanate (A).

Description

[Technical Field]

[0001] The present invention is fever The present invention relates to a curable inkjet ink, more specifically to a thermosetting composition having excellent storage stability at high temperatures and excellent thermosetting properties of the cured film surface under high temperature and high humidity conditions. Things This relates to the thermosetting inkjet ink used. [Background technology]

[0002] Poly(meth)acrylate resins (hereinafter referred to as "acrylic resins") are highly transparent and impact resistant, and are easily thermoplastically formed and colored. As such, they are used as a substitute for inorganic glass in window materials for buildings and vehicles, as well as in a variety of applications as parts for electrical and electronic devices, daily necessities, office supplies, etc.

[0003] The acrylic resin can be produced by adding a radical generator that generates radicals when irradiated with active energy rays such as ultraviolet rays or electron beams to a (meth)acrylate, followed by radical polymerization (crosslinking reaction). Alternatively, the acrylic resin can be produced by adding a peroxide to a (meth)acrylate and heating the mixture to cause radical polymerization.

[0004] For example, Patent Document 1 describes a curable composition used in a method for producing poly(meth)acrylate by polymerizing a monomer having a (meth)acrylate group in the presence of an isocyanate. Patent Document 2 reports a polyurethane composition containing an acrylate having a functional group that reacts with isocyanate.

[0005] It is also known that these thermosetting compositions and photocurable compositions are used to form coating films by photolithography or screen printing, thereby forming etching resists, solder resists and markings for printed circuit boards.

[0006] One method of manufacturing printed circuit boards using an inkjet printer has already been proposed, in which an etching resist is formed by drawing a conductor circuit pattern on a copper-clad laminate for printed wiring boards using an inkjet printer, followed by etching (see, for example, Patent Document 3). Compared to photolithography, which requires a photomask, or screen printing, which requires a screen and uses resist ink or marking ink, this method can significantly reduce the number of steps and labor required, while also reducing the use of consumables such as developers, various inks, and cleaning solvents. It also reduces wastewater, which is expected to contribute to a cleaner environment.

[0007] It has already been proposed to form a hardened film of solder resist using light and heat by using an inkjet method (see, for example, Patent Documents 4, 5, 6 and 7). Specifically, Patent Document 6 discloses a photocurable thermosetting composition that contains an acryloyl group-containing monomer, a blocked polyisocyanate having a triazine skeleton, and a photopolymerization initiator, and is used for printing by an inkjet method. Furthermore, Patent Document 7 discloses a white curable composition for printed wiring boards to be applied to copper wiring and substrates, which contains titanium oxide, a (meth)acrylate having a hydroxy group, a photopolymerization initiator, a wetting and dispersing agent having an acid value, and a specific bifunctional (meth)acrylate compound (excluding those having a hydroxy group).

[0008] However, these thermosetting compositions and thermosetting inkjet inks are still insufficient in terms of storage stability at high temperatures and thermosetting properties of the cured film surface under high temperature and high humidity conditions, and improvements are desired. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 6259394 [Patent Document 2] Special Publication No. 2010-523775 [Patent Document 3] Patent No. 5731746 [Patent Document 4] Patent No. 4936725 [Patent Document 5] Patent No. 5969208 [Patent Document 6] Patent No. 6069300 [Patent Document 7] Patent No. 6488345 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in view of the above problems and circumstances, and the problem to be solved is to provide a thermosetting composition having excellent storage stability at high temperatures and excellent thermosetting properties of the cured film surface under high temperature and high humidity conditions. Things The present invention provides a thermosetting inkjet ink using the same. [Means for solving the problem]

[0011] In the course of investigating the causes of the above problems in order to solve the above problems, the present inventors discovered that by adding a specific amount of a compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate (A) to a thermosetting composition comprising a blocked isocyanate (A) and a poly(meth)acrylate (C), the storage stability at high temperatures can be significantly improved and the thermosetting properties of the cured film surface under high temperature and high humidity conditions can also be increased, thereby arriving at the present invention. That is, the above-mentioned problems of the present invention are solved by the following means.

[0012] 1. Thermosetting resin containing blocked isocyanate (A) Inkjet ink And, The composition contains a compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate (A), and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate, The compound (B) is contained in a range of 0.1 to 20 parts by mass and the blocked isocyanate (A) is contained in a range of 1 to 10 parts by mass relative to 100 parts by mass of the (meth)acryloyl group-containing monomer (C). death, It contains a gelling agent and undergoes a sol-gel phase transition depending on the temperature. The gelling agent is a compound having a structure represented by the following general formula (G1) or (G2): Thermosetting characterized by Inkjet ink . General formula (G1):R 1 -CO-R 2 General formula (G2):R 3 -COO-R 4 (In the formula, R 1 ~R 4 each independently represents an alkyl chain having 12 or more carbon atoms and a linear portion, which may be branched.

[0013] 2. The thermosetting composition according to claim 1, characterized in that it contains a photopolymerization initiator. Inkjet ink .

[0014] 3. The thermosetting composition according to item 1 or 2, wherein the functional group of the compound (B) capable of forming a hydrogen bond with the blocked isocyanate (A) is at least one selected from the group consisting of a hydroxy group, a carboxy group, an amino group, and a mercapto group. Inkjet ink .

[0015] 4. The thermosetting composition according to item 3, wherein the compound (B) is a (meth)acryloyl group-containing monomer. Inkjet ink .

[0016] 5. The thermosetting composition according to any one of items 1 to 4, characterized in that the compound (B) is contained in an amount of 1 to 10 parts by mass relative to 100 parts by mass of the (meth)acryloyl group-containing monomer (C). Inkjet ink .

[0019] 6 Viscosity at 25°C is 1 to 1 x 10 4 and the sol-gel phase transition occurs at a temperature in the range of 40°C or higher and lower than 100°C. From Section 1 No. Any one of the first five items1. The thermosetting inkjet ink according to claim 1.

[0021] 7 The present invention is characterized in that the ink is a thermosetting inkjet ink for forming a solder resist pattern used on a printed circuit board. 1 Section to section 6 Item 1. The thermosetting inkjet ink according to any one of items 1 to 5. [Effects of the Invention]

[0022] The above-mentioned means of the present invention provide a thermosetting composition having excellent storage stability at high temperatures and excellent thermosetting properties of the cured film surface under high temperature and high humidity conditions. Things A thermosetting inkjet ink using the same can be provided.

[0023] The mechanism by which the effects of the present invention are manifested or the mechanism of action is not clear, but is speculated as follows. The stability of blocked isocyanate (A) is explained using the following Structure 1. Structure 1 shows a structure in which blocked isocyanate (A), in which the terminal isocyanate group is blocked with a blocking group, is hydrogen-bonded with compound (B) having active hydrogen.

[0024] It is believed that when compound (B), which has a functional group (having an active hydrogen atom) capable of forming a hydrogen bond with blocked isocyanate (A), forms a hydrogen bond with the R-NHC(=O)-Block (Block represents a blocking group) site of blocked isocyanate (A), the blocked isocyanate (A) and compound (B) form a stable six-membered ring structure as shown in the following Structure 1, thereby improving storage stability at high temperatures. Note that R represents a residue of a blocked isocyanate group, R' represents a residue of a functional group (XH) having active hydrogen, and X preferably represents an oxygen atom, a sulfur atom, or a nitrogen atom.

[0025] [ka]

[0026] Surprisingly, the curing properties of the cured film surface are also improved under high temperature and high humidity conditions. This is thought to be because, after the blocking agent of blocked isocyanate (A) is released during thermal curing, the isocyanate group reacts with compound (B), causing the R' moiety of compound (B), which is mainly composed of hydrocarbon groups, to protrude outward from the molecule, making it easier to orient on the surface of the cured film, thereby increasing the hydrophobicity of the cured film surface. DETAILED DESCRIPTION OF THE INVENTION

[0027] The thermosetting composition of the present invention is a thermosetting composition containing a blocked isocyanate (A), and contains a compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate (A), and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate, and the compound (B) is contained in an amount of 0.1 to 20 parts by mass per 100 parts by mass of the (meth)acryloyl group-containing monomer (C), and the blocked isocyanate (A) is 1~10 The present invention is characterized in that the content of the hydroxybenzoate in the composition is within the range of parts by mass. This feature is a technical feature common to or corresponding to each of the following embodiments (configurations).

[0028] In an embodiment of the present invention, it is preferable to contain a photopolymerization initiator from the viewpoint of improving the curability of the surface of the cured film. Furthermore, it is preferable that the functional group of the compound (B) capable of forming a hydrogen bond with the blocked isocyanate (A) is at least one selected from the group consisting of a hydroxy group, a carboxy group, an amino group, and a mercapto group, since this allows the curability of the film surface to be maintained at a high level. Furthermore, in the present invention, the compound (B) is preferably a (meth)acryloyl group-containing monomer, which can further increase the degree of polymerization of the entire thermosetting composition, thereby improving the thermosetting properties. As an embodiment of the present invention, from the viewpoint of exerting the effects of the present invention, it is preferable that the compound (B) is contained in the range of 1 to 10 parts by mass per 100 parts by mass of the (meth)acryloyl group-containing monomer (C). In addition, the inkjet ink preferably contains the thermosetting composition of the present invention. Furthermore, in the present invention, the thermosetting inkjet ink preferably contains a gelling agent and undergoes a sol-gel phase transition depending on the temperature, which increases the hydrophobicity of the cured film and provides excellent curing properties of the film surface even under high temperature and high humidity conditions. Viscosity at 25°C is 1 to 1 x 10 4 It is preferable that the viscosity of the ink-jet ink is within the range of Pa·s and the sol-gel phase transition occurs at a temperature within the range of 40° C. or higher and lower than 100° C., as this allows the ink-jet ink to be ejected with low viscosity. Furthermore, it is preferable that the gelling agent is a compound having a structure represented by general formula (G1) or general formula (G2), since this increases the hydrophobicity of the cured film and provides excellent curing properties of the film surface under high temperature and high humidity conditions. Furthermore, from the viewpoint of being able to obtain a cured film with high surface hardness, the thermosetting inkjet ink of the present invention is preferably a thermosetting inkjet ink for forming a solder resist pattern used on a printed circuit board.

[0029] The present invention, its components, and embodiments for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as lower and upper limits.

[0030] In the present invention, the term "(meth)acryloyl group" refers to an acryloyl group or a methacryloyl group, and the term "(meth)acrylate" refers to an acrylate or a methacrylate.

[0031] Overview of Thermosetting Composition The thermosetting composition of the present invention is a thermosetting composition containing a blocked isocyanate (A), and contains a compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate (A), and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate, and the compound (B) is contained in an amount of 0.1 to 20 parts by mass per 100 parts by mass of the (meth)acryloyl group-containing monomer (C), and the blocked isocyanate (A) is 1~10 It is characterized in that it is contained in a range of parts by mass.

[0032] The thermosetting composition and thermosetting inkjet ink of the present invention use a blocked isocyanate (A) as a thermosetting agent. The blocking agent in the blocked isocyanate (A) is released by heating at a high temperature, for example, 110 to 180°C for 10 to 60 minutes, thereby initiating thermosetting. However, in practice, the blocking agent is released and the reaction proceeds gradually from temperatures lower than the above, around 80°C, resulting in a problem of increased viscosity. This problem can be improved by increasing the dissociation temperature of the blocking agent, but this results in insufficient thermosetting properties.

[0033] Therefore, in the present invention, a blocked isocyanate (A) having a dissociation temperature within the above temperature range is allowed to interact with a compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate, thereby successfully achieving both high-temperature storage stability and curability.

[0034] Although it is preferable that the number of -NCO functional groups in the blocked isocyanate and the number of active hydrogen-containing moieties in compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate are the same (same number of moles), it has been found that the effects of the present invention can be obtained even when, for example, 1 mole of compound (B) having one active hydrogen-containing moiety is used per mole of a trifunctional blocked isocyanate compound. This is presumably because the charge balance of the entire blocked isocyanate molecule is disrupted when acting on R-NHC(=O)-Block.

[0035] On the other hand, if the composition contains a large amount of compound (B) having a hydrophilic functional group capable of forming a hydrogen bond, the composition may be particularly susceptible to the effects of high temperature and high humidity, which may result in a decrease in the curability of the film surface. However, in the present invention, the composition contains 0.1 to 20 parts by mass of compound (B) having a functional group capable of forming a hydrogen bond with a blocked isocyanate relative to the (meth)acryloyl group-containing monomer (C) that does not have a functional group capable of reacting with a blocked isocyanate, which is the majority of thermosetting compositions and thermosetting inkjet inks, and the composition contains 0.1 to 20 parts by mass of blocked isocyanate (A) relative to 100 parts by mass of the (meth)acryloyl group-containing monomer (C), thereby solving the problem of a decrease in the curability of the film surface.

[0036] In the present invention, it is also preferable to use a photopolymerization initiator in combination. The use of a photopolymerization initiator can increase the degree of polymerization of the cured film and also improve the curability of the cured film surface under high temperature and high humidity conditions. This is believed to be because, as the (meth)acryloyl group-containing monomer (C) undergoes polymerization upon irradiation with light, the viscosity of the film increases, pushing the relatively low molecular weight blocked isocyanate (A) and compound (B) to the surface of the cured film. Subsequently, as described above, during thermal curing, the blocking agent of the blocked isocyanate (A) is released, and the isocyanate group reacts with compound (B). The R' moiety of compound (B), which is primarily composed of a hydrocarbon group, protrudes outward from the molecule, making it more likely to be oriented on the surface of the cured film, further increasing the hydrophobicity of the cured film surface.

[0037] Furthermore, the compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate of the present invention is preferably at least one selected from the group consisting of a hydroxy group, a carboxy group, an amino group, and a mercapto group. It is believed that this highly nucleophilic compound can efficiently act on the R-NHC(=O)-Block moiety of the blocked isocyanate (A) and effectively block the isocyanate group.

[0038] Furthermore, in the present invention, it is preferable to have a gelling agent. It is believed that this is because the portion of the gelling agent consisting of a linear or branched long-chain hydrocarbon group has a high affinity with the R of the blocked isocyanate R-NHC(=O)-Block, which is mainly composed of a hydrocarbon group, making it easier for the -NHC(=O)-Block portion to protrude outward from the molecule, facilitating interaction with the compound (B) according to the present invention. It is also believed that the increased hydrophobicity of the cured film results in excellent thermosetting properties of the cured film surface under high temperature and high humidity conditions.

[0039] <<Details of the Thermosetting Composition>> The thermosetting composition of the present invention will be described in detail below, including its constitution.

[0040] [Blocked isocyanate (A)] In the present invention, a blocked isocyanate (A) having an isocyanate group protected with a thermally dissociable blocking agent is used. By using such a blocked isocyanate (A) in the thermosetting composition, storage stability at high temperatures can be improved. As the compound having an isocyanate group, a polyfunctional isocyanate having two or more isocyanate groups in the molecule is preferred.

[0041] (polyfunctional isocyanate) The polyfunctional isocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups in the molecule.

[0042] Specifically, aromatic polyisocyanates such as 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), and 1,5-naphthalene diisocyanate (NDI); hexamethylene diisocyanate (HDI) aliphatic polyisocyanates such as transcyclohexane-1,4-diisocyanate, trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, and norbornane diisocyanatomethyl (NBDI); alicyclic polyisocyanates such as transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6XDI (hydrogenated XDI), H12MDI (hydrogenated MDI), and H6TDI (hydrogenated TDI); polyisocyanates such as polymethylene polyphenylene polyisocyanate; and biuret, isocyanurate, and carbodiimide-modified products thereof.

[0043] In the present invention, any one of these isocyanates may be used alone, or two or more of them may be used.

[0044] (blocking agent) Known blocking agents can be used, for example, alcohols such as ethanol, n-propanol, isopropanol, t-butanol, and isobutanol, phenols such as phenol, chlorophenol, cresol, xylenol, and p-nitrophenol, alkylphenols such as pt-butylphenol, p-sec-butylphenol, p-sec-aminophenol, p-octylphenol, and p-nonylphenol, basic nitrogen-containing compounds such as 3-hydroxypyridine, 8-hydroxyquinoline, and 8-hydroxyquinaldine, diethyl malonate, ethyl acetoacetate, and acetylacetone. active methylene compounds such as those listed above, acid amides such as acetamide, acrylamide, and acetanilide, acid imides such as succinimide and maleimide, imidazoles such as 2-ethylimidazole and 2-ethyl-4-methylimidazole, pyrazoles such as pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole, lactams such as 2-pyrrolidone and ε-caprolactam, oximes of ketones or aldehydes such as acetoxime, methyl ethyl ketone oxime, cyclohexanone oxime, and acetaldoxime, ethyleneimine, and bisulfites.

[0045] The thermally dissociable blocking agent is preferably at least one compound selected from the group consisting of oxime compounds, pyrazole compounds, and active ethylene compounds, in terms of ink storage stability and thermal dissociation properties. Examples of the oxime compounds include formamide oxime, acetaldoxime, acetoxime, methyl ethyl ketone oxime, and cyclohexanone oxime.

[0046] Examples of the pyrazole compounds include pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole.

[0047] Examples of the active ethylene compounds include dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, and acetylacetone.

[0048] Examples of the polyfunctional isocyanate compound having an isocyanate group protected with a blocking agent include 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, 2-[(3-butylidene)aminooxycarbonylamino]ethyl methacrylate, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl acrylate, and 2-[(3-butylidene)aminooxycarbonylamino]ethyl acrylate.

[0049] The content of the blocked isocyanate (A) is 0.1 to 20 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the (meth)acryloyl group-containing monomer (C). If the amount of (A) is less than 0.1 part by mass, thermal curing is insufficient, and if the amount of (A) is more than 20 parts by mass, the high-temperature storage stability of the thermosetting composition and the thermally configured inkjet ink is reduced.

[0050] The blocking agent may be used alone or in combination of two or more kinds. Alternatively, a plurality of blocked isocyanates blocked with a single blocking agent or two or more kinds of blocking agents may be used.

[0051] Examples of commercially available blocked isocyanates include BI7961 and BI7992 (both manufactured by Baxenden), MF-K60X (manufactured by Asahi Kasei Chemicals Corporation), VPLS2253, and BL4265SN (both manufactured by Sumika Bayer Urethane Co., Ltd.).

[0052] [Compound (B) having a functional group capable of forming a hydrogen bond with a blocked isocyanate] In the present invention, the "functional group capable of forming a hydrogen bond with a blocked isocyanate" refers to a functional group having active hydrogen, and examples thereof include a hydroxy group, a carboxy group, an amino group, and a mercapto group.

[0053] Preferred examples of the hydroxy group include C1 to C18 alcohols, phenols, and (meth)acrylates having a hydroxy group. Specific examples include phenol, p-cresol, ethyl salicylate, ethyl p-hydroxybenzoate, propylene glycol, and propylene glycol monomethyl ether.

[0054] The carboxy group is preferably a C1 to C18 aliphatic carboxylic acid or aromatic carboxylic acid, specifically benzoic acid.

[0055] The amino group is preferably a primary amine or a secondary amine, and examples thereof include C1 to C18 aliphatic amines and aromatic amines, specifically aniline, acetanilide, etc.

[0056] The mercapto group is preferably a C1 to C18 aliphatic mercaptan or aromatic mercaptan, and specific examples include 1-butanethiol and thiophenol.

[0057] Furthermore, in the present invention, the compound (B) is preferably a monomer containing a (meth)acryloyl group, and the monomer containing a (meth)acryloyl group is preferably an acrylate.

[0058] Examples of monofunctional (meth)acrylates having a hydroxy group include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-methyl-2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxymethylcyclohexylmethyl (meth)acrylate, p-hydroxymethylphenylmethyl (meth)acrylate, Examples of the hydroxyalkyl (meth)acrylates include 2-(hydroxyethoxy)ethyl (meth)acrylate, 2-(hydroxyethoxyethoxy)ethyl (meth)acrylate, 2-(hydroxyethoxyethoxyethoxy)ethyl (meth)acrylate, methyl α-hydroxymethylacrylate, ethyl α-hydroxymethylacrylate, hydroxyalkyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl acrylate.

[0059] Examples of polyfunctional (meth)acrylates having a hydroxy group include 2-hydroxy-3-acryloyloxypropyl methacrylate, dipentaerythritol penta(meth)acrylate, ethylene oxide-added pentaerythritol tetra(meth)acrylate, trimethylolpropane diacrylate, glycerin di(meth)acrylate, glycerin acrylate methacrylate, pentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol propionate tri(meth)acrylate, hydroxypivalaldehyde-modified dimethylolpropane tri(meth)acrylate, sorbitol tri(meth)acrylate, sorbitol tetra(meth)acrylate, sorbitol penta(meth)acrylate, and pentaerythritol tri(meth)acrylate.

[0060] When the functional group capable of forming a hydrogen bond with the blocked isocyanate (A) is a hydroxy group, the compound (B) is preferably a compound represented by the following general formula (1) or a polyfunctional acrylate having a hydroxy group.

[0061] General formula (1) Z-R4-OH (In general formula (1), Z represents CH2=CR1-COO-. R1 represents a hydrogen atom or a methyl group. R4 represents an organic residue containing 2 to 20 carbon atoms.)

[0062] In the above general formula (1), the organic residue represented by R4 is preferably a linear, branched, or cyclic alkylene group having 2 to 20 carbon atoms, an alkylene group having 2 to 20 carbon atoms containing an oxygen atom in its structure via an ether bond and / or an ester bond, or an optionally substituted aromatic group having 6 to 11 carbon atoms. Among these, a linear, branched, or cyclic alkylene group having 2 to 6 carbon atoms, or an alkylene group having 2 to 9 carbon atoms containing an oxygen atom in its structure via an ether bond is preferred.

[0063] Specific examples of the compound (B) represented by the general formula (1) above include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-methyl-2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxymethylcyclohexylmethyl (meth)acrylate, p-hydroxymethylphenylmethyl (meth)acrylate, 2-(hydroxyethoxy)ethyl (meth)acrylate, 2-(hydroxyethoxyethoxy)ethyl (meth)acrylate, 2-(hydroxyethoxyethoxyethoxy)ethyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl acrylate. Examples of polyfunctional acrylates having a hydroxy group include pentaerythritol triacrylate and dipentaerythritol pentaacrylate.

[0064] From the viewpoint of curing speed, more preferred examples of compound (B) include 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, alicyclic carboxylic acid-based epoxy acrylates such as pentaerythritol triacrylate and acrylic modified products of hexahydrodiphthalic acid glycidyl diester, and dipentaerythritol pentaacrylate, with pentaerythritol triacrylate being particularly preferred.

[0065] Examples of the (meth)acryloyl group-containing monomer having a carboxy group include acrylic acid and methacrylic acid.

[0066] The content of the compound (B) is preferably 0.1 to 20 parts by mass, and more preferably 1 to 10 parts by mass, of the blocked isocyanate (A) per 100 parts by mass of the (meth)acryloyl group-containing monomer (C). If the content of the compound (B) is less than 0.1 part by mass, the storage stability at high temperatures will be poor, and if it is more than 20 parts by mass, the curability of the cured film of the thermosetting composition and the thermally configured inkjet ink under high temperature and high humidity conditions will be reduced.

[0067] [(Meth)acryloyl group-containing monomer (C) having no functional group reactive with blocked isocyanate] In the present invention, the (meth)acryloyl group-containing monomer (C) that does not have a functional group capable of reacting with a blocked isocyanate has one or more (meth)acryloyl groups in one molecule. The (meth)acryloyl group-containing monomer is a compound that does not have a functional group that can react with isocyanate. The functional group that can react with isocyanate has already been described in the description of compound (B).

[0068] Examples of the (meth)acrylate used in the present invention include monofunctional (meth)acrylates such as 2-(2-ethoxyethoxy)ethyl (meth)acrylate, butyl (meth)acrylate, stearyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, and 2-phenoxyethyl (meth)acrylate, as well as 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and diethylene Examples of the polyfunctional (meth)acrylate compound include difunctional (meth)acrylates such as glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, and neopentyl glycol diacrylate, trifunctional (meth)acrylates such as trimethylolpropane triacrylate, and polyfunctional (meth)acrylate compounds including tetrafunctional or higher (meth)acrylates such as ditrimethylolpropane tetraacrylate and dipentaerythritol hexaacrylate. The above monomers having a (meth)acryloyl group may be used alone or in combination of two or more kinds.

[0069] [Gelling agent] The gelling agent according to the present invention is preferably maintained in a uniformly dispersed state in the cured film cured by light and heat, which makes it possible to prevent moisture from penetrating into the cured film. Such gelling agents are preferably at least one compound selected from the group consisting of compounds represented by the following general formula (G1) or (G2), in that they are dispersed in the cured film without inhibiting the curing of the ink, and are also preferred in that they have good pinning properties in inkjet printing, can achieve both fine lines and a thick film, and are excellent in fine line reproducibility.

[0070] General formula (G1): R1-CO-R2 General formula (G2): R3-COO-R4 (In the formula, R1 to R4 each independently represent an alkyl chain having 12 or more carbon atoms and a linear portion, which may be branched.) The ketone wax represented by the general formula (G1) or the ester wax represented by the general formula (G2) has a linear or branched hydrocarbon group (alkyl chain) with 12 or more carbon atoms, which increases the crystallinity of the gelling agent, improves water resistance, and creates more space in the house-of-card structure described below. This makes it easier for ink media such as solvents and photopolymerizable compounds to be fully enclosed in the space, improving the pinning ability of the ink.

[0071] Furthermore, the number of carbon atoms in the linear or branched hydrocarbon group (alkyl chain) is preferably 26 or less. If the number of carbon atoms is 26 or less, the melting point of the gelling agent does not become excessively high, and therefore it is not necessary to heat the ink excessively when ejecting the ink.

[0072] From the above viewpoint, it is particularly preferable that R1 and R2, or R3 and R4, are linear hydrocarbon groups having 12 to 23 carbon atoms.

[0073] Furthermore, from the viewpoint of increasing the gelling temperature of the ink and causing the ink to gel more rapidly after impact, it is preferable that either R1 or R2, or either R3 or R4, is a saturated hydrocarbon group having from 12 to 23 carbon atoms. From the above viewpoint, it is more preferable that both R1 and R2, or both R3 and R4, are saturated hydrocarbon groups having 11 or more and less than 23 carbon atoms.

[0074] Examples of the ketone wax represented by the general formula (G1) include dilignoceryl ketone (C24-C24), dibehenyl ketone (C22-C22), distearyl ketone (C18-C18), dieicosyl ketone (C20-C20), dipalmityl ketone (C16-C16), dimyristyl ketone (C14-C14), dilauryl ketone (C12-C12), lauryl myristyl ketone ( These include: lauryl palmityl ketone (C12-C14), lauryl palmityl ketone (C12-C16), myristyl palmityl ketone (C14-C16), myristyl stearyl ketone (C14-C18), myristyl behenyl ketone (C14-C22), palmityl stearyl ketone (C16-C18), palmityl behenyl ketone (C16-C22), and stearyl behenyl ketone (C18-C22). Note that the number of carbon atoms in the parentheses above indicates the number of carbon atoms in each of the two hydrocarbon groups separated by the carbonyl group.

[0075] Commercially available examples of the ketone wax represented by general formula (G1) include Stearonne (manufactured by Alfa Aeser; Stearon), 18-Pentatriacontanone (manufactured by Alfa Aeser), Hentriacontan-16-one (manufactured by Alfa Aeser), and Kaowax T-1 (manufactured by Kao Corporation).

[0076] Examples of fatty acid or ester waxes represented by general formula (G2) include behenyl behenate (C21-C22), icosanoic acid icosyl (C19-C20), stearyl stearate (C17-C18), palmityl stearate (C17-C16), lauryl stearate (C17-C12), cetyl palmitate (C15-C16), stearyl palmitate (C15-C18), ), myristyl myristate (C13-C14), cetyl myristate (C13-C16), octyldodecyl myristate (C13-C20), stearyl oleate (C17-C18), stearyl erucate (C21-C18), stearyl linoleate (C17-C18), behenyl oleate (C18-C22), and arachidyl linoleate (C17-C20). The number of carbon atoms in the parentheses above indicates the number of carbon atoms in each of the two hydrocarbon groups separated by the ester group.

[0077] Commercially available examples of the ester wax represented by general formula (G2) include Unistar M-2222SL and Sperm Acetate, manufactured by NOF Corporation ("Unistar" is a registered trademark of the company), Exepar SS and Exepar MY-M, manufactured by Kao Corporation ("Exepar" is a registered trademark of the company), EMALEX CC-18 and EMALEX CC-10, manufactured by Nippon Emulsion Co., Ltd. ("EMALEX" is a registered trademark of the company), and Amuleps PC, manufactured by Kokyu Alcohol Kogyo Co., Ltd. ("Amuleps" is a registered trademark of the company).

[0078] These commercially available products are often mixtures of two or more types, and may be separated and purified as necessary before being added to the ink. Of these gelling agents, ketone wax, ester wax, higher fatty acid, higher alcohol, and fatty acid amide are preferred from the viewpoint of further enhancing pinning properties.

[0079] The content of the gelling agent according to the present invention is preferably within the range of 0.5 to 5.0% by mass relative to the total mass of the ink. By setting the content of the gelling agent within this range, the solubility of the gelling agent in the solvent component and the pinning effect are improved, and further, the water resistance of the cured film is improved. From the above viewpoint, the content of the gelling agent in the inkjet ink is more preferably within the range of 0.5 to 2.5% by mass.

[0080] Furthermore, from the following viewpoint, it is preferable that the gelling agent crystallizes in the ink at a temperature equal to or lower than the gelling temperature of the ink. The gelling temperature is the temperature at which the gelling agent undergoes a phase transition from sol to gel when the ink, which has been solated or liquefied by heating, is cooled, causing a sudden change in the viscosity of the ink. Specifically, the solated or liquefied ink is cooled while its viscosity is measured using a viscoelasticity measuring device (e.g., MCR300, manufactured by Physica), and the temperature at which the viscosity suddenly increases can be determined to be the gelling temperature of the ink.

[0081] [Photopolymerization initiator] As the photopolymerization initiator according to the present invention, it is preferable to use a photoradical initiator when the photopolymerizable compound is a radical polymerizable compound, and to use a photoacid generator when the photopolymerizable compound is a cationically polymerizable compound.

[0082] The thermosetting inkjet ink of the present invention may contain only one type of photopolymerization initiator, or may contain two or more types of photopolymerization initiators. The photopolymerization initiator may be a combination of both a photoradical initiator and a photoacid generator.

[0083] Photoradical initiators include cleavage-type radical initiators and hydrogen abstraction-type radical initiators.

[0084] Examples of cleavage-type radical initiators include acetophenone-based initiators, benzoin-based initiators, acylphosphine oxide-based initiators, benzyl and methylphenyl glyoxyesters.

[0085] Examples of acetophenone-based initiators include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzil dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone.

[0086] Examples of benzoin-based initiators include benzoin, benzoin methyl ether, and benzoin isopropyl ether.

[0087] Examples of acylphosphine oxide initiators include 2,4,6-trimethylbenzoindiphenylphosphine oxide.

[0088] Examples of the hydrogen abstraction type radical initiator include benzophenone-based initiators, thioxanthone-based initiators, aminobenzophenone-based initiators, 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, and camphorquinone.

[0089] Examples of benzophenone-based initiators include benzophenone, o-benzoylmethylbenzoate-4-phenylbenzophenone, 4,4′-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, acrylated benzophenone, 3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone, and 3,3′-dimethyl-4-methoxybenzophenone.

[0090] Examples of thioxanthone initiators include 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone.

[0091] Examples of aminobenzophenone initiators include Michler's ketone and 4,4'-diethylaminobenzophenone.

[0092] Examples of photoacid generators include the compounds described in Organic Electronics Materials Research Group, "Imaging Organic Materials," Bunshin Publishing (1993), pp. 187-192.

[0093] The content of the photopolymerization initiator may be within a range that allows the ink to be sufficiently cured, and may be, for example, within a range of 0.01 to 10% by mass relative to the total mass of the thermosetting inkjet ink of the present invention (hereinafter also simply referred to as the ink of the present invention).

[0094] Examples of commercially available photopolymerization initiators include Irgacure TPO (manufactured by BASF), 819 (manufactured by BASF), Irgacure 379 (manufactured by BASF), Genocure ITX (manufactured by Rahn AG), and Genocure EPD (manufactured by Rahn AG).

[0095] The ink of the present invention may further contain a photopolymerization initiator aid, a polymerization inhibitor, and the like, as required.

[0096] The photoinitiator coagent may be a tertiary amine compound, preferably an aromatic tertiary amine compound.

[0097] Examples of aromatic tertiary amine compounds include N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethyl-p-toluidine, N,N-dimethylamino-p-benzoic acid ethyl ester, N,N-dimethylamino-p-benzoic acid isoamyl ethyl ester, N,N-dihydroxyethylaniline, triethylamine, and N,N-dimethylhexylamine. Among these, N,N-dimethylamino-p-benzoic acid ethyl ester and N,N-dimethylamino-p-benzoic acid isoamyl ethyl ester are preferred. These compounds may be used alone or in combination of two or more.

[0098] [Coloring agent] The ink of the present invention may further contain a colorant, if necessary. The colorant may be a dye or a pigment, but a pigment is preferred because it has good dispersibility in the components of the ink and excellent weather resistance. The pigment is not particularly limited, but examples include organic pigments or inorganic pigments with the following numbers listed in the Color Index.

[0099] Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 43, 48:1, 48:2, 48:3, 48:4, 48:5, 49:1, 53:1, 57:1, 57:2, 58:4, 63:1, 81, 81:1, 81:2, 81:3, 81:4, 88, 104, 108, 112, 122, 123, 144, 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, and Pigment Orange. 13, 16, 20, 36 or a mixture thereof.

[0100] Examples of blue or cyan pigments include pigments selected from Pigment Blue 1, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17-1, 22, 27, 28, 29, 36, and 60, or mixtures thereof.

[0101] Examples of green pigments include pigments selected from Pigment Green 7, 26, 36, 50, or mixtures thereof.

[0102] Examples of yellow pigments include pigments selected from Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, and 193, or mixtures thereof.

[0103] Examples of black pigments include pigments selected from Pigment Black 7, 28, and 26, or mixtures thereof.

[0104] Examples of commercially available pigments include Black Pigment (manufactured by Mikuni), Chromofine Yellow 2080, 5900, 5930, AF-1300, 2700L, Chromofine Orange 3700L, 6730, Chromofine Scarlet 6750, Chromofine Magenta 6880, 6886, 6891N, 6790, 6887, Chromofine Violet RE, Chromofine Red 6820, 6830, Chromofine Blue HS-3, 5187, 5108, 5197, 5085N, SR-5020, 5026, 5050, 4920, 4927, 4937, 4824, 4933GN-EP, 4940, 4973, 5205, 5208, 5214, 5221, 5000P, Chrome Fine Green 2GN, 2GO, 2G-550D, 5310, 5370, 6830, Chrome Fine Black A-1103, Seika Fast Yellow 10GH, A-3, 2035, 2054, 2200, 2270, 2300, 2400(B), 2500, 2600, ZAY-260, 2700(B), 2770, Seikafast Red 8040, C405(F), CA120, LR-116, 1531B, 8060R, 1547, ZAW-262, 1537B, GY, 4R-4016, 3820, 3891, ZA-215, Seikafast Carmine 6B1476T-7, 1483LT, 3840, 3870, Seikafast Bordeaux 10B-430, Seikalite Rose R40, Seikalite Violet B800, 7805, Seikafast Maroon 460N, Seikafast Orange 900, 2900, Seikalite Blue C718, A612, Cyanine Blue 4933M, 4933GN-EP, 4940, 4973 (all manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.); KET Yellow 401, 402, 403, 404, 405, 406, 416, 424, KET Orange 501, KET Red 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 336, 337, 338, 346, KET Blue 101, 102, 103, 104, 105, 106, 111, 118, 124, KET Green 201 (manufactured by DIC);Colortex Yellow 301, 314, 315, 316, P-624, 314, U10GN, U3GN, UNN, UA-414, U263, Finecol Yellow T-13, T-05, Pigment Yellow1705, Colortex Orange 202, Colortex Red101, 103, 115, 116, D3B, P-625, 102, H-1024, 105C, UFN, UCN, UBN, U3BN, URN, UGN, UG276, U456, U457, 105C, USN, Colortex Maroon601, Colortex BrownB610N, Colortex Violet600, Pigment Red122, Colortex Blue516, 517, 518, 519, A818, P-908, 510, Colortex Green 402, 403, Colortex Black 702, U905 (all manufactured by Sanyo Dye Co., Ltd.); Lionol Yellow 1405G, Lionol Blue FG7330, FG7350, FG7400G, FG7405G, ES, ESP-S (all manufactured by Toyo Ink Co., Ltd.); Toner Magenta E02, Permanent Rubin F6B, Toner Yellow HG, Permanent Yellow GG-02, Hostapearm Blue B2G (all manufactured by Hoechst Industries); Novoperm P-HG, Hostaperm Pink E, Hostaperm Blue B2G (all manufactured by Clariant); carbon black #2600, #2400, #2350, #2200, #1000, #990, #980, #970, #960, #950, #850, MCF88, #750, #650, MA600, MA7, MA8, MA11, MA100, MA100R, MA77, #52, #50, #47, #45, #45L, #40, #33, #32, #30, #25, #20, #10, #5, #44, and CF9 (all manufactured by Mitsubishi Chemical Corporation) are examples.

[0105] The pigment can be dispersed using, for example, a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, a paint shaker, or the like.

[0106] The pigment is preferably dispersed so that the volume average particle size of the pigment particles is preferably within a range of 0.08 to 0.5 μm, and the maximum particle size is preferably within a range of 0.3 to 10 μm, more preferably within a range of 0.3 to 3 μm.

[0107] The dispersion of the pigment is adjusted by selecting the pigment, dispersant, and dispersion medium, and by adjusting the dispersion conditions and filtration conditions.

[0108] The ink of the present invention may further contain a dispersant to improve the dispersibility of the pigment. Examples of dispersants include carboxylic acid esters having a hydroxy group, salts of long-chain polyaminoamides and high-molecular-weight acid esters, salts of high-molecular-weight polycarboxylic acids, salts of long-chain polyaminoamides and polar acid esters, high-molecular-weight unsaturated acid esters, polymeric copolymers, modified polyurethanes, modified polyacrylates, polyether ester-type anionic surfactants, naphthalenesulfonic acid-formalin condensate salts, aromatic sulfonic acid-formalin condensate salts, polyoxyethylene alkyl phosphate esters, polyoxyethylene nonylphenyl ether, and stearylamine acetate. Examples of commercially available dispersants include the Solsperse series from Avecia and the PB series from Ajinomoto Fine-Techno Co., Ltd.

[0109] The ink of the present invention may further contain a dispersing aid, if necessary, which may be selected depending on the pigment. The total amount of the dispersant and dispersion aid is preferably within the range of 1 to 50% by mass relative to the pigment.

[0110] The ink of the present invention may further contain a dispersion medium for dispersing the pigment, if necessary. A solvent may be contained in the ink as the dispersion medium, but in order to prevent the solvent from remaining in the formed image, it is preferable to use a photopolymerizable compound (particularly a monomer with low viscosity) as described above as the dispersion medium.

[0111] The dye may be an oil-soluble dye.

[0112] Examples of oil-soluble dyes include the following various dyes: Examples of magenta dyes include MS Magenta VP, MS Magenta HM-1450, MS Magenta HSo-147 (all manufactured by Mitsui Chemicals, Inc.), AIZEN SOT Red-1, AIZEN SOT Red-2, AIZEN SOT Red-3, AIZEN SOT Pink-1, SPIRON Red GEH SPECIAL (all manufactured by Hodogaya Chemical Co., Ltd.), RESOLIN Red FB 200%, MACROLEX Red Violet R, MACROLEX ROT5B (all manufactured by Bayer Japan Ltd.), KAYASET Red B, KAYASET Red 130, KAYASET Red 802 (all manufactured by Nippon Kayaku Co., Ltd.), PHLOXIN, ROSE BENGAL, ACID Red (all manufactured by Daiwa Chemical Industry Co., Ltd.), HSR-31, DIARESIN Red K (all manufactured by Mitsubishi Chemical Corporation), and Oil Red (manufactured by BASF Japan Ltd.).

[0113] Examples of cyan dyes include MS Cyan HM-1238, MS Cyan HSo-16, Cyan HSo-144, and MS Cyan VPG (all manufactured by Mitsui Chemicals, Inc.), AIZEN SOT Blue-4 (manufactured by Hodogaya Chemical Co., Ltd.), RESOLIN BR.Blue BGLN 200%, MACROLEX Blue RR, CERES Blue GN, SIRIUS SUPRATURQ.Blue Z-BGL, and SIRIUS SUPRA TURQ.Blue FB-LL 330% (all manufactured by Bayer Japan KK), KAYASET Blue FR, KAYASET Blue N, KAYASET Blue 814, Turq.Blue GL-5 200, and Light Blue BGL-5200 (all manufactured by Nippon Kayaku Co., Ltd.), DAIWA Blue 7000 and OleosolFast Blue GL (all manufactured by Daiwa Chemical Industry Co., Ltd.), DIARESIN Blue P (manufactured by Mitsubishi Chemical Corporation), and SUDAN Blue 670, NEOPEN Blue 808, ZAPON Blue 806 (all manufactured by BASF Japan Ltd.), etc.

[0114] Examples of yellow dyes include MS Yellow HSm-41, Yellow KX-7, Yellow EX-27 (all manufactured by Mitsui Chemicals, Inc.), AIZEN SOT Yellow-1, AIZEN SOT Yellow-3, AIZEN SOT Yellow-6 (all manufactured by Hodogaya Chemical Co., Ltd.), MACROLEX Yellow 6G, MACROLEX FLUOR. Yellow 10GN (all manufactured by Bayer Japan KK), KAYASET Yellow SF-G, KAYASET Yellow 2G, KAYASET Yellow AG, KAYASET Yellow EG (all manufactured by Nippon Kayaku Co., Ltd.), DAIWA Yellow 330HB (manufactured by Daiwa Chemical Industry Co., Ltd.), HSY-68 (manufactured by Mitsubishi Chemical Corporation), SUDAN Yellow 146, NEOPEN Yellow 075 (all manufactured by BASF Japan Ltd.), and the like.

[0115] Examples of black dyes include MS Black VPC (manufactured by Mitsui Chemicals, Inc.), AIZEN SOT Black-1, AIZEN SOT Black-5 (all manufactured by Hodogaya Chemical Co., Ltd.), RESOLIN Black GSN 200%, RESOLIN Black BS (all manufactured by Bayer Japan KK), KAYASET Black AN (manufactured by Nippon Kayaku Co., Ltd.), DAIWA Black MSC (manufactured by Daiwa Chemical Industry Co., Ltd.), HSB-202 (manufactured by Mitsubishi Chemical Corporation), NEPTUNE Black X60, NEOPEN Black X58 (all manufactured by BASF Japan KK), and the like.

[0116] The ink of the present invention may contain one or more colorants and may be toned to a desired color. The content of the colorant is preferably in the range of 0.1 to 20% by mass, and more preferably in the range of 0.4 to 10% by mass, based on the total amount of the ink.

[0117] [Other ingredients] The ink of the present invention may further contain other components including a polymerization inhibitor and a surfactant, as long as the effects of the present invention are obtained. The ink of the present invention may contain only one of these components, or two or more of them.

[0118] (polymerization inhibitor) Examples of the polymerization inhibitor include (alkyl)phenols, hydroquinone, catechol, resorcinol, p-methoxyphenol, t-butylcatechol, t-butylhydroquinone, pyrogallol, 1,1-picrylhydrazyl, phenothiazine, p-benzoquinone, nitrosobenzene, 2,5-di-t-butyl-p-benzoquinone, dithiobenzoyl disulfide, picric acid, cupferron, aluminum N-nitrosophenylhydroxyamine, tri-p-nitrophenylmethyl, N-(3-oxyanilino-1,3-dimethylbutylidene)aniline oxide, dibutyl cresol, cyclohexanone oxime cresol, guaiacol, o-isopropylphenol, butyraldoxime, methyl ethyl ketoxime, and cyclohexanone oxime.

[0119] Examples of commercially available polymerization inhibitors include Irgastab UV10 (manufactured by BASF) and Genorad 18 (manufactured by Rahn AG).

[0120] The amount of the polymerization inhibitor can be set arbitrarily as long as the effects of the present invention are obtained, and can be, for example, 0.001% by mass or more and less than 1.0% by mass relative to the total mass of the ink.

[0121] (surfactant) Examples of surfactants include anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, and fatty acid salts; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene-polyoxypropylene block copolymers; cationic surfactants such as alkylamine salts and quaternary ammonium salts; and silicone-based and fluorine-based surfactants.

[0122] Examples of silicone surfactants include polyether-modified polysiloxane compounds, specifically Tego rad 2250 manufactured by Evonik, KF-351A, KF-352A, KF-642, and X-22-4272 manufactured by Shin-Etsu Chemical Co., Ltd., BYK307, BYK345, BYK347, and BYK348 manufactured by BYK-Chemie ("BYK" is a registered trademark of the company), and TSF4452 manufactured by Momentive Performance Materials.

[0123] The fluorine-based surfactant refers to a surfactant in which part or all of the hydrogen atoms bonded to the carbon atoms of the hydrophobic group of a normal surfactant are substituted with fluorine. Examples of fluorine-based surfactants include Megafac F manufactured by DIC Corporation ("Megafac" is a registered trademark of DIC), Surflon manufactured by AGC Sei Chemical Co., Ltd. ("Surflon" is a registered trademark of AGC Sei Chemical Co., Ltd.), Fluorad FC manufactured by 3M Corporation ("Fluorad" is a registered trademark of 3M), Monflor manufactured by Imperial Chemical Industries, Ltd., Zonyls manufactured by E.I. duPont Nemerus and Company, Licowet VPF manufactured by Lubbewerke-Hoechst, and FTERGENT manufactured by Neos Corporation ("FTERGENT" is a registered trademark of 3M).

[0124] The amount of surfactant can be set arbitrarily as long as the effects of the present invention are obtained, and can be, for example, 0.001% by mass or more and less than 1.0% by mass relative to the total mass of the ink.

[0125] (curing accelerator) In the present invention, a curing accelerator may be contained as needed. The curing accelerator is not particularly limited as long as it accelerates the thermal curing of the resin component. Examples of the curing accelerator include imidazoles, dicyandiamide derivatives, dicarboxylic acid dihydrazides, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, 2-ethyl-4-methylimidazole-tetraphenylborate, and 1,8-diazabicyclo[5.4.0]undecene-7-tetraphenylborate.

[0126] (coupling agent) In the present invention, various coupling agents may be contained as necessary, which can improve adhesion to copper foil. Examples of various coupling agents include silane-based, titanium-based, and aluminum-based coupling agents.

[0127] (ion scavenger) In the present invention, an ion scavenger may be contained as needed. The inclusion of an ion scavenger has advantages such as adsorbing ionic impurities and improving the insulating properties of the cured film when it absorbs moisture.

[0128] Examples of the ion trapping agent include inorganic ion adsorbents such as triazine thiol compounds, bisphenol-based reducing agents, zirconium compounds, and antimony-bismuth-based magnesium aluminum compounds.

[0129] (solvent) In the thermosetting composition of the present invention and the ink of the present invention, it is essentially preferable to use no solvent from the viewpoint of curability, but a solvent may be added to adjust the viscosity of the ink.

[0130] [Physical Properties] The ink of the present invention preferably contains a gelling agent. In this case, the viscosity of the ink of the present invention at 25°C is 1 to 1 × 10 4 A viscosity within the Pa·s range is preferable in that the ink is sufficiently gelled when it lands and is cooled to room temperature, resulting in good pinning properties.

[0131] Furthermore, from the viewpoint of further improving the ejection properties from an inkjet head, the viscosity of the ink of the present invention at 80° C. is preferably within the range of 3 to 20 mPa·s, and more preferably within the range of 7 to 9 mPa·s.

[0132] Furthermore, when the ink of the present invention contains a gelling agent, it preferably has a phase transition point in the range of 40°C or higher and lower than 100°C. If the phase transition point is 40°C or higher, the ink quickly gels after landing on a recording medium, resulting in higher pinning properties. If the phase transition point is lower than 100°C, the ink is easier to handle and has higher ejection stability.

[0133] From the viewpoint of enabling the ink to be ejected at a lower temperature and reducing the load on the image forming apparatus, the phase transition point of the ink of the present invention is more preferably within the range of 40 to 60°C.

[0134] The viscosity at 80° C., viscosity at 25° C. and phase transition point of the ink of the present invention can be determined by measuring the temperature change of the dynamic viscoelasticity of the ink using a rheometer.

[0135] In the present invention, these viscosities and phase transition points are values ​​obtained by the following methods.

[0136] The ink of the present invention is heated to 100°C, and the viscosity is measured using a Physica MCR301 (manufactured by Anton Paar) at a shear rate of 1000 (1 / s). The ink is then cooled to 20°C under conditions of a shear rate of 11.7 (1 / s) and a cooling rate of 0.1°C / s, to obtain a temperature curve of viscosity.

[0137] The viscosities at 80°C and 25°C can be determined by reading the viscosities at 80°C and 25°C on the viscosity temperature curve. The phase transition point can be determined as the temperature at which the viscosity reaches 200 mPa s on the viscosity temperature curve.

[0138] From the viewpoint of improving ejection properties from an inkjet head, the average dispersed particle size of the pigment particles according to the present invention is preferably in the range of 50 to 150 nm, and the maximum particle size is preferably in the range of 300 to 1000 nm, and more preferably in the range of 80 to 130 nm.

[0139] The average dispersed particle size of pigment particles in this invention refers to the value determined by dynamic light scattering using a Datasizer Nano ZSP (manufactured by Malvern). Note that inks containing colorants have high concentrations, and light does not pass through this measuring device. Therefore, the ink is diluted 200 times before measurement. The measurement temperature is room temperature (25°C).

[0140] [Method for forming solder resist film] The thermosetting inkjet ink of the present invention is preferably an ink for forming a solder resist pattern used on a printed circuit board. When a solder resist pattern (solder resist film) is formed using the thermosetting inkjet ink of the present invention, it is possible to prevent moisture from penetrating into the solder resist film, resulting in good adhesion between the copper foil and the solder resist film on the printed circuit board, and also preventing copper migration and suppressing deterioration of insulation properties.

[0141] The method for forming a solder resist film using the thermosetting inkjet ink of the present invention preferably includes the steps of: (1) ejecting the ink of the present invention from the nozzles of an inkjet head and causing it to land on a printed circuit board on which a circuit has been formed; and (3) heating the ink to fully cure it.

[0142] When the ink of the present invention contains a compound having a photopolymerizable functional group and a photopolymerization initiator, it is preferable to include a step (step (2)) between the above steps (1) and (3) in which the deposited ink is irradiated with actinic rays to temporarily cure the ink.

[0143] <Step (1)> In step (1), droplets of the ink of the present invention are ejected from an inkjet head and landed on a printed circuit board, which is a recording medium, at positions corresponding to the resist film to be formed, thereby forming a pattern.

[0144] The ejection method from the inkjet head may be either an on-demand method or a continuous method.

[0145] The on-demand inkjet head may be of any of the following types: electro-mechanical conversion type, such as single cavity type, double cavity type, bender type, piston type, shear mode type, and shared wall type; and electro-thermal conversion type, such as thermal inkjet type and Bubble Jet (registered trademark) type (Bubble Jet is a registered trademark of Canon Inc.).

[0146] Discharging ink droplets from an inkjet head in a heated state can improve discharge stability. The ink temperature during discharge is preferably in the range of 40 to 100°C, and more preferably in the range of 40 to 90°C to further improve discharge stability. In particular, it is preferable to perform discharge at an ink temperature that results in an ink viscosity in the range of 7 to 15 mPa·s, more preferably in the range of 8 to 13 mPa·s.

[0147] In order to improve the ejection properties of sol-gel phase transition ink from an inkjet head, it is preferable that the temperature of the ink when filled into the inkjet head be set to (gelation temperature + 10)°C to (gelation temperature + 30)°C. If the temperature of the ink inside the inkjet head is (gelation temperature + 10)°C or higher, the ink will not gel inside the inkjet head or on the nozzle surface, which will result in a decrease in ink ejection properties. On the other hand, if the temperature of the ink inside the inkjet head is within (gelation temperature + 30)°C, the ink will not become too hot and the ink components will not deteriorate.

[0148] The method for heating the ink is not particularly limited. For example, at least one of the ink supply system, such as the ink tank constituting the head carriage, the supply pipe, and the anterior ink tank immediately before the head, the piping with a filter, and the piezo head, can be heated by a panel heater, a ribbon heater, or heated water.

[0149] The amount of ink droplets ejected is preferably within the range of 2 to 20 pL in terms of recording speed and image quality.

[0150] The printed circuit board is not particularly limited, but examples thereof include copper-clad laminates of all grades (FR-4, etc.) made of materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, copper-clad laminates for high-frequency circuits made of fluorine-polyethylene-PPO-cyanate ester, and other materials, as well as polyimide films, PET films, glass substrates, ceramic substrates, wafer plates, stainless steel plates, etc.

[0151] <Step (2)> In the step (2), the ink that has been deposited in the step (1) is irradiated with actinic rays to temporarily cure the ink. The actinic ray can be selected from, for example, electron beams, ultraviolet rays, α rays, γ rays, and X-rays, and is preferably ultraviolet rays.

[0152] The ultraviolet light can be irradiated at a wavelength of 395 nm using, for example, a water-cooled LED manufactured by Phoseon Technology Co., Ltd. Using an LED as the light source can prevent ink from melting due to the radiant heat of the light source, thereby preventing poor ink curing.

[0153] The ultraviolet irradiation is carried out such that the peak irradiance of the ultraviolet light on the surface of the resist film having a wavelength in the range of 370 to 410 nm is preferably 0.5 to 10 W / cm. 2 in the range of 1 to 5 W / cm 2 From the viewpoint of suppressing the radiation heat from being irradiated onto the ink, the amount of light irradiated onto the resist film is set to 500 mJ / cm 2 It is preferable that it is less than 10 ...

[0154] The irradiation of actinic rays is preferably carried out within 0.001 to 300 seconds after the ink has landed, and more preferably within 0.001 to 60 seconds in order to form a highly precise resist film.

[0155] <Step (3)> In step (3), after the preliminary curing in step (2), the ink is further heated to fully cure it. The heating method is preferably, for example, placing the product in an oven set at a temperature in the range of 110 to 180° C. for 10 to 60 minutes.

[0156] The thermosetting inkjet ink of the present invention can be used as an adhesive, a sealant, a circuit protectant, etc. for electronic components, in addition to being used as an ink for forming the above-mentioned solder resist pattern. [Example]

[0157] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the examples, the terms "parts" and "%" are used, but unless otherwise specified, they represent "parts by mass" or "% by mass."

[0158] Example 1 [Preparation of Thermosetting Compositions 1-1 to 1-44] The ratios shown in Tables I to III are those having functional groups capable of forming hydrogen bonds with the blocked isocyanate (A). The compound (B) having a blocked isocyanate and the (meth)acryloyl group-containing monomer (C) having no functional group reactive with the blocked isocyanate were mixed and stirred with a dissolver to obtain thermosetting compositions 1-1 to 1-44.

[0159] [Preparation of Thermosetting Compositions 1-45 to 1-58] The combined amount of the compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate (A) and the (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate was 96% by mass of the entire thermosetting composition. The ratio of the amounts added is shown in Table III. Furthermore, the following amounts of a photopolymerization initiator and a photopolymerization initiator aid were added: This was stirred with a dissolver to obtain thermosetting compositions 1-45 to 1-58. Photopolymerization initiator Irgacure TPO (manufactured by BASF): 1.0% by mass Photopolymerization initiator Genocure ITX (Rahn AG): 3.0% by mass

[0160] [Formation of cured films 1-1 to 1-58] Using these thermosetting compositions 1 to 58, films with a thickness of 30 μm were formed on BT substrates using an applicator (manufactured by ERICHSEN), and thermosetting compositions 1-1 to 1-44 were cured at 160°C for 30 minutes to form cured films 1-1 to 1-44. In addition, for the thermosetting compositions 1-45 to 1-58, an LED lamp (395 nm, 8 W / cm) manufactured by Phoseon Technology was used. 2 , water cooled unit) at 500mJ / cm 2 The film was cured by irradiation so as to become 160° C., and then cured for 30 minutes at 160° C. to form cured films 1-45 to 1-58.

[0161] The compounds shown in the table below are shown. <Blocked isocyanate (A)> A-1: Trixene BI7961 (manufactured by LANXESS, biuret type, blocking agent: DMP (dimethylpyrazole)) A-2: Trixene BI7982 (manufactured by LANXESS, blocking agent: DMP) A-3: Trixene BI7992 (manufactured by LANXESS, blocking agent: DMP / DEM (diethyl malonate), active ethylene-based compound) A-4: BL4265SN (manufactured by Sumika Bayer Urethane Co., Ltd., blocking agent: MEKO (methyl ethyl ketoxime), an oxime-based compound) A-5: Trixene BI7991 (LANXESS, biuret type, blocking agent: DMP / DEM) A-6: Desmodur BL 1100 / 1 (manufactured by Sumika Bayer Urethane Co., Ltd., blocking agent: ε-caprolactam)

[0162] <Compound (B) Having a Functional Group Capable of Forming a Hydrogen Bond with Blocked Isocyanate> B-1: Ethyl salicylate B-2: Ethyl p-hydroxybenzoate B-3: p-cresol B-4: Benzoic acid B-5: Aniline B-6: Acetanilide B-7: Thiophenol B-8: 2-hydroxybutyl acrylate (Light Ester HOB-A: manufactured by Kyoeisha Chemical Co., Ltd.) B-9: Alicyclic carboxylic acid-based epoxy acrylate (DA-722: manufactured by Nagase ChemteX Corporation) B-10: Dipentaerythritol pentaacrylate (Miramer M500: manufactured by MIWON) B-11: Methacrylic acid B-12: 2-hydroxy-3-phenoxypropyl acrylate (Light Acrylate M-600A: manufactured by Kyoeisha Chemical Co., Ltd.) B-13: 2-hydroxy-3-acryloyloxypropyl methacrylate (Light Ester G-201P: manufactured by Kyoeisha Chemical Co., Ltd.)

[0163] <(C) (meth)acryloyl group-containing monomer not having a functional group capable of reacting with blocked isocyanate> C-1: Dipropylene glycol diacrylate (DPGDA: M222 manufactured by Miwon) C-2: TMP(EO)9TA (trimethylolpropane EO-modified triacrylate) (EM2382, manufactured by Choko Chemical Co., Ltd.) C-3: Phenyl glycidyl ether acrylate hexamethylene diisocyanate urethane prepolymer (urethane acrylate AH-600: manufactured by Kyoeisha Chemical Co., Ltd.)

[0164] "evaluation" The storage stability at high temperatures and the pencil hardness of the cured film were evaluated. [Storage stability at high temperatures] The viscosity of each of the prepared thermosetting compositions 1-1 to 1-58 was measured at 25°C, and then the composition was stored in a sealed container at 85°C for 500 hours. The composition was then allowed to cool to 25°C, and the viscosity after high-temperature treatment was measured. The viscosity increase rate (%) was calculated and evaluated according to the following criteria. The viscosity was measured using a Physica MCR301 (manufactured by Anton Paar) at a shear rate of 1000 (1 / s). Viscosity increase rate (%) = (viscosity after 500 hours - initial viscosity) / initial viscosity x 100.

[0165] ◎: Viscosity increase rate is less than 5% ○: Viscosity increase rate is 5% or more and less than 10% △: Viscosity increase rate is 10% or more but less than 20% ×: Viscosity increase rate is 20% or more, or solidification occurs

[0166] [Pencil hardness] Each of the cured films 1-1 to 1-58 formed by heat curing or heat curing and photocuring was subjected to a pencil hardness test in accordance with JIS K 5400 using a Hi-uni pen made by Mitsubishi Pencil Co., Ltd.

[0167] Specifically, the wood of a pencil was scraped off, leaving a lead 5-6 mm long. The tip of the lead was polished smoothly with abrasive paper to obtain a circular cross section. This pencil was held at a 45-degree angle to the sample surface, and a weight of 1 kg was applied to the sample surface, scratching the coating at a 45-degree angle. The maximum hardness of the pencil whose coating did not reach the substrate was evaluated.

[0168] [Pencil hardness under high temperature and humidity] Each of the cured films 1-1 to 1-58 formed by the above-described heat curing or heat curing plus photocuring was left to stand for 500 hours under conditions of 85°C and a relative humidity of 85%. Thereafter, the pencil hardness was evaluated in the same manner as described above, and the peeling state of the cured film was observed. The results are shown in Tables I to III. In the following tables, the blocked isocyanate (A) The compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate and the (meth)acryloyl group-containing monomer (C) not having a functional group capable of reacting with the blocked isocyanate are referred to as the compound (B) having a functional group capable of forming a hydrogen bond and the (meth)acryloyl group-containing monomer (C), respectively.

[0169] [Table 1]

[0170] [Table 2]

[0171] [Table 3]

[0172] As is clear from the results shown in Tables I to III, the compounds within the scope of the present invention are materials that are excellent in storage stability and thermosetting properties when stored at high temperatures, and in thermosetting properties under high temperature and high humidity. Furthermore, it is clear that a thermosetting composition containing 1 to 10 parts by mass of a compound (B) having a functional group capable of forming a hydrogen bond, or 1 to 10 parts by mass of a blocked isocyanate (A) per 100 parts by mass of a (meth)acryloyl group-containing monomer (C), has even better ink storage stability.

[0173] It is also apparent that when the compound (B) having a functional group capable of forming a hydrogen bond is a (meth)acryloyl group-containing monomer, the ink storage stability and pencil hardness are excellent. Furthermore, it is clear that the thermosetting composition irradiated with light using a photopolymerization initiator has excellent pencil hardness.

[0174] Example 2 [Preparation of inkjet ink] <Preparation of Yellow Pigment Dispersion> Dispersant 1 and Dispersant 2 shown below and the dispersion medium were placed in a stainless steel beaker, heated on a hot plate at 65°C for 1 hour while stirring and dissolving, and then cooled to room temperature, after which the pigment shown below was added, and the mixture was placed in a glass bottle together with 200 g of zirconia beads with a diameter of 0.5 mm and sealed. This was dispersed in a paint shaker until the desired particle size was reached, and then the zirconia beads were removed.

[0175] Dispersant 1: EFKA7701 (manufactured by BASF) 5.6 parts by mass Dispersant 2: Solsperse 22000 (manufactured by Lubrizol Japan) 0.4 parts by mass Dispersion medium: dipropylene glycol diacrylate (containing 0.2% UV-10) 80.6 parts by mass Pigment: PY185 (BASF, Paliotol Yellow D1155) 13.4 parts by mass

[0176] <Preparation of Cyan Pigment Dispersion> The yellow pigment dispersion was prepared in the same manner as in the preparation of the yellow pigment dispersion, except that the dispersant, dispersion medium, and pigment were changed as shown below.

[0177] Dispersant: EFKA7701 (BASF) 7 parts by mass Dispersion medium: dipropylene glycol diacrylate (containing 0.2% UV-10) 70 parts by mass Pigment: PB15:4 (Dainichi Seika Chemicals, Chromofine Blue 6332JC) 23 parts by mass

[0178] <Gelling agent> The gelling agents used were as follows: D-1: Distearyl ketone D-2: Behenyl behenate

[0179] <Photopolymerization initiator> The TPO and ITX described in Example 1 were used.

[0180] <Blocked isocyanate (A)> A-1 to A-6 described in Example 1 were used. <Compound (B) Having a Functional Group Capable of Forming a Hydrogen Bond with Blocked Isocyanate> B-1 to B-13 described in Example 1 were used.

[0181] <(C) (meth)acryloyl group-containing monomer not having a functional group capable of reacting with blocked isocyanate> The above-mentioned C-1 to C-3 were used.

[0182] [Preparation of Thermosetting Inkjet Ink] The thermosetting inkjet inks were each formulated according to the composition shown below, stirred with a dissolver, and filtered through a Teflon (registered trademark) 3 μm membrane filter manufactured by ADVATEC to prepare thermosetting inkjet inks 2-1 to 2-68.

[0183] Preparation of Thermosetting Inkjet Inks 2-1 to 2-41 The blocked isocyanate (A), the compound (B) having a functional group capable of hydrogen bonding, and the (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate were combined to make 93.0 parts by mass of the entire composition. The ratios of the amounts added are shown in Tables IV and V. The following components were also included. Yellow pigment dispersion: 1.0% by mass Cyan pigment dispersion: 2.0% by mass Photopolymerization initiator: TPO: 1.0% by mass Photopolymerization initiator: ITX: 3.0% by mass

[0184] Preparation of Thermosetting Inkjet Inks 2-42 to 2-56 The blocked isocyanate (A), the compound (B) having a functional group capable of hydrogen bonding, and the (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate were combined to make 90.0 parts by mass of the entire composition. The ratios of the amounts added are shown in Tables V and VI. The following components were also included. Yellow pigment dispersion: 1.0% by mass Cyan pigment dispersion: 2.0% by mass Gelling agent D-1: 2.0% by mass Gelling agent D-2: 1.0% by mass Photopolymerization initiator: TPO: 1.0% by mass Photopolymerization initiator: ITX: 3.0% by mass

[0185] Preparation of Thermosetting Inkjet Inks 2-57 to 2-62 The total amount of the blocked isocyanate (A), the compound (B) having a functional group capable of hydrogen bonding, and the (meth)acryloyl group-containing monomer (C) not having a functional group capable of reacting with the blocked isocyanate was 97.0 parts by mass of the entire composition. The addition ratios are shown in Table VI. The following components were also included. Yellow pigment dispersion: 1.0% by mass Cyan pigment dispersion: 2.0% by mass

[0186] Preparation of Thermosetting Inkjet Inks 2-63 to 2-68 The total amount of the blocked isocyanate (A), the compound (B) having a functional group capable of hydrogen bonding, and the (meth)acryloyl group-containing monomer (C) not having a functional group capable of reacting with the blocked isocyanate was 94.0 parts by mass of the entire composition. The addition ratios are shown in Table VI. The following components were also included. Yellow pigment dispersion: 1.0% by mass Cyan pigment dispersion: 2.0% by mass Gelling agent D-1: 2.0% by mass Gelling agent D-2: 1.0% by mass

[0187] (Measurement of viscosity and gel phase transition temperature) The viscosity at 80° C. and gel phase transition temperature of each of the prepared thermosetting inkjet inks were measured using a Physica MCR301 (manufactured by Anton Paar) at a shear rate of 1000 (1 / s).

[0188] Here, the gel phase transition temperature is the temperature at which the complex viscosity becomes 1 Pa s or higher in the viscoelasticity curve obtained by changing the temperature at a cooling rate of 0.1°C / s, a strain of 5%, an angular frequency of 10 radian / s, and a cooling rate of 0.1°C / s.

[0189] The viscosity of the ink containing the gelling agent of the present invention at 25°C is in the range of 1 to 1 × 10 4 The inks containing no gelling agent all had a viscosity of less than 1 Pa·s. Furthermore, the gel phase transition temperatures of the inks containing the gelling agent of the present invention were all between 40 and 100°C, but the gel phase transition phenomenon was not observed in the inks containing no gelling agent.

[0190] <Patterning with thermosetting inkjet ink> Each thermosetting inkjet ink prepared was loaded into an inkjet recording device having an inkjet recording head equipped with a piezoelectric inkjet nozzle. Using this device, a pattern was formed on a copper-clad laminate for printed wiring boards (FR-4, thickness 1.6 mm, size 150 mm × 95 mm).

[0191] The ink supply system consists of an ink tank, ink flow path, a sub-ink tank just before the inkjet recording head, piping with a metal filter, and a piezo head. The ink is heated to 90°C from the ink tank to the head. A heater is also built into the piezo head, heating the ink temperature inside the recording head to 90°C. The piezo head has a nozzle diameter of 22 μm, and the nozzles with a nozzle resolution of 360 dpi are arranged in a staggered pattern to form a nozzle row with a resolution of 720 dpi.

[0192] Using this inkjet device, a voltage was applied so that the droplet volume would be 6.0 pl dots, and a 20 mm × 50 mm solid pattern and a comb-shaped pattern with a line and space of 100 μm were printed on the substrate, each with a thickness of 20 μm. After that, an LED lamp (395 nm, 8 W / cm) manufactured by Phoseon Technology was used to print the patterns. 2 , water cooled unit) at 500mJ / cm 2 The ink layer was temporarily cured by irradiating it so that the temperature was 150°C for 60 minutes, and then the ink layer was fully cured to obtain a print sample.

[0193] "evaluation" The inkjet ink prepared above and the coating film formed thereon were evaluated for shelf life of the inkjet ink and pencil hardness of the coating film formed thereon in the same manner as in Example 1. The results are shown in Tables IV to VI.

[0194] [Table 4]

[0195] [Table 5]

[0196] [Table 6]

[0197] As is clear from the results shown in Tables IV to VI, the thermosetting inkjet ink of the present invention is a material that is excellent in storage stability and thermal and photocurability. Furthermore, it is clear that compositions containing 1 to 10 parts by mass of a compound (B) having a functional group capable of forming a hydrogen bond, or 1 to 10 parts by mass of a blocked isocyanate (A) per 100 parts by mass of a (meth)acryloyl group-containing monomer (C), have even better ink storage stability.

[0198] Furthermore, it was found that ink preservation properties were even better when the compound (B) having a functional group capable of forming a hydrogen bond had a specific functional group. This is presumably because the structure facilitates hydrogen bonding to the blocked moiety of the blocked isocyanate.

[0199] It is also apparent that the addition of a gelling agent to the heat- and light-curable composition of the present invention further improves the ink storage stability and heat-curing properties. [Industrial Applicability]

[0200] The thermosetting composition of the present invention has excellent storage stability at high temperatures and excellent thermosetting properties of the cured film surface under high temperature and high humidity conditions, and can be preferably used in thermosetting inkjet inks.

Claims

1. A thermosetting inkjet ink containing a blocked isocyanate (A), The composition contains a compound (B) having a functional group capable of forming a hydrogen bond with the blocked isocyanate (A), and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate, the compound (B) is contained in a range of 0.1 to 20 parts by mass and the blocked isocyanate (A) is contained in a range of 1 to 10 parts by mass relative to 100 parts by mass of the (meth)acryloyl group-containing monomer (C); Contains a gelling agent and undergoes sol-gel phase transition depending on temperature. The thermosetting inkjet ink is characterized in that the gelling agent is a compound having a structure represented by the following general formula (G1) or (G2): General formula (G1): R 1 -CO-R 2 General formula (G2): R 3 -COO-R 4 (In the formula, R 1 to R 4 each independently represent an alkyl chain having 12 or more carbon atoms and a linear portion, which may be branched.)

2. 2. The thermosetting inkjet ink according to claim 1, further comprising a photopolymerization initiator.

3. 3. The thermosetting inkjet ink according to claim 1, wherein the functional group of the compound (B) capable of forming a hydrogen bond with the blocked isocyanate (A) is at least one selected from the group consisting of a hydroxy group, a carboxy group, an amino group, and a mercapto group.

4. 4. The thermosetting inkjet ink according to claim 3, wherein the compound (B) is a (meth)acryloyl group-containing monomer.

5. 5. The thermosetting inkjet ink according to claim 1, wherein the compound (B) is contained in an amount in the range of 1 to 10 parts by mass per 100 parts by mass of the (meth)acryloyl group-containing monomer (C).

6. Viscosity at 25°C is 1 to 1 x 10 4 6. The thermosetting inkjet ink according to claim 1, wherein the viscosity is in the range of Pa·s and the sol-gel phase transition occurs at a temperature in the range of 40°C or higher but lower than 100°C.

7. 7. The thermosetting ink-jet ink according to claim 1, which is a thermosetting ink-jet ink for forming a solder resist pattern used on a printed circuit board.

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