Thermosetting composition and thermosetting inkjet ink

Abstract

To provide a thermosetting composition excellent in storage stability at high temperature and in thermosetting properties of a cured film surface under high temperature and high humidity, and to provide a thermosetting inkjet ink using the thermosetting composition.SOLUTION: The thermosetting composition of the present invention contains: a blocked isocyanate (A); 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 a blocked isocyanate. The thermosetting composition contains the compound (B) within the range of 0.1-20 pts.mass and the blocked isocyanate (A) within the range of 1-10 pts.mass based on 100 pts.mass of the (meth)acryloyl group-containing monomer (C). The compound (B) is a polyfunctional (meth)acryloyl group-containing monomer having a hydroxy group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermosetting composition and a thermosetting inkjet ink. More specifically, the present invention relates to a thermosetting composition excellent in storage stability at high temperatures and the thermosetting property of the surface of a cured film under high temperature and high humidity, and a thermosetting inkjet ink using the same.

Background Art

[0002] Poly(meth)acrylate resin (hereinafter also referred to as "acrylic resin") has high transparency and impact resistance, and is easy to thermoplastically form and color. Therefore, it is used as a substitute for inorganic glass in window materials for buildings and vehicles, etc., and is also applied to various uses as parts in electric and electronic devices, daily necessities, office supplies, etc.

[0003] Acrylic resin can be produced by adding a radical generator that generates radicals by irradiating (meth)acrylate with active energy rays such as ultraviolet rays or electron beams, and subjecting it to radical polymerization (crosslinking reaction). It can also be produced by radical polymerization by adding a peroxide to (meth)acrylate and heating.

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

[0005] In addition, it is known to form a coating film by a photolithography method or a screen printing method using these thermosetting compositions or photocurable compositions, and to form an etching resist, a solder resist, and a marking of a printed circuit board.

[0006] As a method for manufacturing a printed circuit board using an inkjet printer, a method has already been proposed in which an etching resist is formed by drawing a conductor circuit pattern on a copper-clad laminate for a printed wiring board using an inkjet printer and then performing an etching process (see, for example, Patent Document 3). This method can significantly reduce the number of processes and labor compared to the photolithography method that requires a photomask or the screen printing method that uses resist ink or marking ink that requires a screen plate. At the same time, consumables such as developers, various inks, and cleaning solvents can be reduced, and wastewater can also be reduced, so environmental cleaning can be expected.

[0007] Regarding the solder resist, it has already been proposed to form a cured film by light and heat using an inkjet method (see, for example, Patent Documents 4, 5, 6, and 7). Specifically, Patent Document 6 discloses a photocurable thermosetting composition containing an acryloyl group-containing monomer, a block polyisocyanate having a triazine skeleton, and a photopolymerization initiator and used for printing by an inkjet method. In addition, Patent Document 7 discloses a white curable composition for a printed wiring board that is applied to a copper wiring and a substrate and contains titanium oxide, a (meth)acrylate having a hydroxy group, a photopolymerization initiator, a wetting dispersant having an acid value, and further a specific bifunctional (meth)acrylate compound (excluding those having a hydroxy group).

[0008] However, the storage stability at high temperatures and the thermosetting property of the cured film surface under high temperature and high humidity of these thermosetting compositions and thermosetting inkjet inks are not yet sufficient and improvement is desired.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

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

[0011] In order to solve the above problems, the present inventor has found that in a thermosetting composition comprising a blocked isocyanate (A) and a poly(meth)acrylate (C), by containing a compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate (A) in a specific amount, the storage stability at high temperatures can be significantly improved, and the thermosetting properties of the surface of the cured film under high temperature and high humidity can also be enhanced, leading to the present invention. That is, the above problems according to the present invention are solved by the following means.

[0012] 1. A thermosetting composition containing a blocked isocyanate (A), comprising a compound (B) having a functional group capable of hydrogen bonding 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 an amount of 0.1 to 20 parts by mass and the blocked isocyanate (A) is contained in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C). The compound (B) is a polyfunctional (meth)acryloyl group-containing monomer having a hydroxy group. A thermosetting composition characterized by the above.

[0013] 2. The thermosetting composition according to claim 1, wherein the compound (B) is 2-hydroxy-3-acryloyloxypropyl methacrylate, dipentaerythritol penta(meth)acrylate, ethylene oxide-added pentaerythritol tetra(meth)acrylate, trimethylolpropane diacrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate propionate, hydroxypivalaldehyde-modified dimethylolpropane tri(meth)acrylate, sorbitol tri(meth)acrylate, sorbitol tetra(meth)acrylate, sorbitol penta(meth)acrylate, pentaerythritol tri(meth)acrylate, or an acrylic-modified product of glycidyl diester of hexahydrophthalic acid.

[0014] 3. The thermosetting composition according to claim 1, wherein the compound (B) is an alicyclic carboxylic acid-based epoxy acrylate.

[0015] 4. The thermosetting composition according to any one of claims 1 to 3, containing a photopolymerization initiator.

[0016] 5. The thermosetting composition according to any one of claims 1 to 4, wherein the compound (B) is contained in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C).

[0017] 6. A thermosetting inkjet ink characterized by containing the thermosetting composition according to any one of claims 1 to 5.

[0018] 7. The thermosetting inkjet ink according to claim 6, characterized by containing a gelling agent and undergoing a sol-gel phase transition depending on temperature.

[0019] 8. The viscosity at 25°C is in the range of 1 to 1×10 4 Pa·s, and the thermosetting inkjet ink according to claim 7, characterized in that the sol-gel phase transition occurs within the range of 40°C or higher and less than 100°C.

[0020] 9. The thermosetting inkjet ink according to claim 7 or 8, characterized in that the gelling agent is a compound having a structure represented by the following general formula (G1) or general formula (G2). 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 a linear portion of 12 or more carbon atoms and may have a branch.)

[0021] 10. The thermosetting inkjet ink according to any one of claims 6 to 9, which is a thermosetting inkjet ink for forming a solder resist pattern used for a printed circuit board.

Advantages of the Invention

[0022] By the above means of the present invention, it is possible to provide a thermosetting composition excellent in storage stability at high temperatures and thermosetting properties of the surface of the cured film under high temperature and high humidity, and a thermosetting inkjet ink using the same.

[0023] Although the mechanism of manifestation or the mechanism of action of the effects of the present invention is not clearly understood, it is presumed as follows. The following Structure 1 explains the stability of blocked isocyanate (A). Structure 1 shows a structure in which the blocked isocyanate (A) with a terminal isocyanate group blocked by a blocking group forms a hydrogen bond with a compound (B) having an active hydrogen.

[0024] At the site of R-NHC(=O)-Block (Block represents a blocking group) of blocked isocyanate (A), a compound (B) having a functional group capable of forming a hydrogen bond with blocked isocyanate (A) (having an active hydrogen atom) forms a hydrogen bond. Thus, as shown in the following Structure 1, blocked isocyanate (A) and compound (B) form a stable six-membered ring structure, and it is presumed that the storage stability at high temperatures can be improved. Here, R represents the residue of the blocked isocyanate group, R′ represents the residue of the functional group (XH) having an active hydrogen, and X preferably represents an oxygen atom, a sulfur atom, or a nitrogen atom.

[0025]

Chemical Formula

[0026] Also, surprisingly, the curability of the surface of the cured film under high temperature and high humidity is also improved. This is presumably because after the blocking agent of blocked isocyanate (A) is removed during thermosetting, the isocyanate group reacts with compound (B), and the R′ site mainly composed of a hydrocarbon group of compound (B) protrudes to the outside of the molecule and is likely to be oriented on the surface of the cured film, resulting in higher hydrophobicity on the surface of the cured film.

Embodiments for Carrying Out the Invention

[0027] The thermosetting composition of the present invention is a thermosetting composition containing a blocked isocyanate (A), a compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate (A), and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate. It contains the compound (B) in the range of 0.1 to 20 parts by mass and the blocked isocyanate (A) in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C). This feature is a technical feature common to or corresponding to the following respective embodiments (forms).

[0028] As an embodiment of the present invention, from the viewpoint of improving the curability of the cured film surface, it is preferable to contain a photopolymerization initiator. Moreover, it is preferable that the functional group capable of hydrogen bonding with the blocked isocyanate (A) possessed by the compound (B) is at least one selected from the group consisting of a hydroxy group, a carboxy group, an amino group, and a mercapto group, because the curability of the film surface can be maintained high. Furthermore, in the present invention, it is preferable that the compound (B) is a (meth)acryloyl group-containing monomer. Thereby, since the degree of polymerization of the entire thermosetting composition can be further improved, the thermosetting property can be improved. As an embodiment of the present invention, from the viewpoint of expressing the effects of the present invention, it is preferable to contain the compound (B) in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C). Moreover, it is preferable that it is an inkjet ink containing the thermosetting composition of the present invention. Furthermore, in the present invention, it is preferable that it is a thermosetting inkjet ink containing a gelling agent and undergoing a sol-gel phase transition depending on temperature. Thereby, the hydrophobicity of the cured film is increased, and an effect of excellent curability of the film surface under high temperature and high humidity can be obtained. The viscosity at a temperature of 25°C is 1 to 1×10 4It is preferable that the sol-gel phase transition occurs within the range of Pa·s and within the range of a temperature of 40°C or higher and lower than 100°C, since inkjet ink with low viscosity can be ejected. Further, it is preferable that the gelling agent is a compound having a structure represented by the general formula (G1) or general formula (G2), since the hydrophobicity of the cured film increases and the curability of the film surface under high temperature and high humidity is excellent. Furthermore, from the viewpoint of obtaining 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 for a printed circuit board.

[0029] Hereinafter, the present invention, its components, and embodiments and modes for carrying out the present invention will be described in detail. In the present application, "~" is used in the sense of including the numerical values described before and after as the lower limit value and the upper limit value.

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

[0031] 《Outline of Thermosetting Composition》 The thermosetting composition of the present invention is a thermosetting composition containing a blocked isocyanate (A), a compound (B) having a functional group capable of hydrogen bonding 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 the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C), and the blocked isocyanate (A) is contained in the range of 0.1 to 20 parts by mass.

[0032] The thermosetting composition and thermosetting inkjet ink of the present invention use blocked isocyanate (A) as a thermosetting agent. The blocking agent of blocked isocyanate (A) is removed by heating at a high temperature, for example, 110 to 180 °C for 10 to 60 minutes, and then thermosetting starts. However, in reality, the blocking agent starts to come off from around 80 °C, which is lower than the above temperature, and the reaction proceeds little by little. As a result, an increase in viscosity has been a problem. Although this problem can be improved by raising the dissociation temperature of the blocking agent, the thermosetting property will become insufficient.

[0033] Therefore, in the present invention, by interacting a compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate (A) having a dissociation temperature within the above temperature range, it has been successful in achieving both storage stability and curability at high temperatures.

[0034] Also, it is preferable that the number of -NCO functional groups of the blocked isocyanate and the number of sites having active hydrogen of the compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate are the same (the same number of moles). However, for example, it has been found that the effects of the present invention can be obtained even when 1 mol of a compound (B) having one site with active hydrogen is used with respect to 1 mol of a trifunctional type blocked isocyanate compound. This is presumably because the charge balance of the entire blocked isocyanate molecule is disrupted when it acts on R-NHC(=O)-Block.

[0035] On the one hand, by containing a large amount of the compound (B) having a hydrophilic hydrogen-bondable functional group, it is particularly susceptible to the influence under high temperature and high humidity, and there is a risk of reducing the curability of the film surface. However, in the present invention, for the (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate, which is most of the thermosetting composition and the thermosetting inkjet ink, 0.1 to 20 parts by mass of the compound (B) having a functional group capable of hydrogen-bonding with the blocked isocyanate is contained, and 0.1 to 20 parts by mass of the blocked isocyanate (A) is contained with respect to 100 parts by mass of the above (meth)acryloyl group-containing monomer (C), thereby solving the problem of the reduction in the curability of the film surface.

[0036] In addition, in the present invention, it is preferable to further use a photopolymerization initiator in combination. By using the photopolymerization initiator in combination, it is possible to increase the degree of polymerization of the cured film, and furthermore, the curability of the surface of the cured film under high temperature and high humidity can also be improved. This is because when the polymerization of the (meth)acryloyl group-containing monomer (C) proceeds by light irradiation, the relative low molecular weight blocked isocyanate (A) and the compound (B) are extruded to the surface of the cured film due to the increase in viscosity in the film. Then, as described above, during thermal curing, the blocking agent of the blocked isocyanate (A) is removed, the isocyanate group reacts with the compound (B), and the R' part mainly composed of a hydrocarbon group of the compound (B) protrudes to the outside of the molecule and is likely to be oriented on the surface of the cured film, so it is presumed that the hydrophobicity of the surface of the cured film is further increased.

[0037] In addition, the compound (B) having a functional group capable of hydrogen-bonding 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 presumed that it has high nucleophilicity and can effectively act on the R-NHC(=O)-Block part of the blocked isocyanate (A) to effectively block the isocyanate group.

[0038] In addition, in the present invention, it is preferable to have a gelling agent. It is presumed that a site composed of a linear or branched long-chain hydrocarbon group of the gelling agent easily binds to R mainly composed of a hydrocarbon group of R-NHC(=O)-Block of the blocked isocyanate, so that the -NHC(=O)-Block site easily protrudes outside the molecule, and the compound (B) according to the present invention easily interacts. Further, since the hydrophobicity of the cured film increases, it is presumed that the cured film surface also has excellent thermosetting properties under high temperature and high humidity.

[0039] 《Details of the thermosetting composition》 Hereinafter, the thermosetting composition of the present invention will be described in detail regarding its configuration and the like.

[0040] [Blocked isocyanate (A)] In the present invention, a blocked isocyanate (A) having an isocyanate group protected by a thermally dissociable blocking agent is used. By using such a blocked isocyanate (A) in the thermosetting composition, the 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 preferable.

[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), 1,5-naphthalene diisocyanate (NDI); aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate methyl (NBDI); alicyclic polyisocyanates such as transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6XDI (hydrogenated XDI), H12MDI (hydrogenated MDI), H6TDI (hydrogenated TDI); polyisocyanates such as polymethylene polyphenylene polyisocyanate; burette bodies, isocyanurate bodies and carbodiimide modified products thereof; and the like can be mentioned.

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

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

[0045] It is preferable that the heat-dissociable blocking agent is at least one compound selected from the group consisting of oxime-based compounds, pyrazole-based compounds, and active ethylene-based compounds in terms of ink storage stability and heat dissociation properties. Examples of oxime-based compounds include formamide oxime, acetaldehyde oxime, acetoxime, methyl ethyl ketone oxime, cyclohexanone oxime, etc.

[0046] Examples of pyrazole-based compounds include pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, etc.

[0047] Examples of active ethylene-based compounds include dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, etc.

[0048] Examples of the polyfunctional isocyanate compound having an isocyanate group protected by the 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, preferably 1 to 10 parts by mass, of the blocked isocyanate (A) with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C). When (A) is less than 0.1 part by mass, curing by heat is insufficient, and when it is contained in more than 20 parts by mass, the storage stability of the thermosetting composition and the thermosetting inkjet ink at high temperatures decreases.

[0050] The above blocking agent may be used alone or in combination of two or more, and a plurality of types of blocked isocyanates blocked with a single type or two or more types of blocking agents may also be used.

[0051] Examples of the product names of commercially available blocked isocyanates include BI7961, BI7992 (both manufactured by Baxenden), MF-K60X (manufactured by Asahi Kasei Chemicals), VPLS2253, BL4265SN (both manufactured by Sumika Bayer Urethane), etc.

[0052] [Compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate] The "functional group capable of hydrogen bonding with the blocked isocyanate" in the present invention is a functional group having active hydrogen, and examples thereof include a hydroxy group, a carboxy group, an amino group, and a mercapto group.

[0053] As the hydroxy group, C1-C18 alcohols, phenols, and (meth)acrylates having a hydroxy group are preferred. Specifically, phenol, p-cresol, ethyl salicylate, ethyl p-hydroxybenzoate, propylene glycol, propylene glycol monomethyl ether, etc. may be mentioned.

[0054] As the carboxy group, C1-C18 aliphatic carboxylic acids and aromatic carboxylic acids are preferred. Specifically, benzoic acid, etc. may be mentioned.

[0055] As the amino group, primary amines and secondary amines are preferred, and C1-C18 aliphatic amines and aromatic amines may be mentioned. Specifically, aniline, acetanilide, etc. may be mentioned.

[0056] As the mercapto group, C1-C18 aliphatic mercaptans and aromatic mercaptans are preferred, and specifically, 1-butanethiol, thiophenol, etc. may be mentioned.

[0057] Furthermore, in the present invention, it is preferable that the compound (B) is a monomer containing a (meth)acryloyl group. The monomer having 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, 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, 2-hydroxy-3-phenoxypropyl acrylate, and the like.

[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 tri(meth)acrylate propionate, hydroxypivalaldehyde-modified dimethylolpropane tri(meth)acrylate, sorbitol tri(meth)acrylate, sorbitol tetra(meth)acrylate, sorbitol penta(meth)acrylate, pentaerythritol tri(meth)acrylate, and the like.

[0060] In addition, when the functional group capable of hydrogen bonding 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 carbon atoms in the range of 2 to 20.)

[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 having an oxygen atom due to an ether bond and / or an ester bond in the structure, 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 having an oxygen atom due to an ether bond in the structure is preferable.

[0063] Specific examples of the compound (B) represented by the above general formula (1) 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, 2-hydroxy-3-phenoxypropyl acrylate, and the like. Examples of the polyfunctional acrylate having a hydroxy group include pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and the like.

[0064] More preferable specific examples of the compound (B) include, from the viewpoint of the curing rate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, or alicyclic carboxylic acid-based epoxy acrylate such as pentaerythritol triacrylate and acrylic-modified product of glycidyl diester of hexahydrophthalic acid, dipentaerythritol pentaacrylate, and among them, pentaerythritol triacrylate is preferable.

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

[0066] The content of the compound (B) is preferably included in the range of 0.1 to 20 parts by mass of the blocked isocyanate (A) with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C), and more preferably included in the range of 1 to 10 parts by mass. When the content of the compound (B) is less than 0.1 part by mass, the storage stability at high temperature is poor, and when it is contained more than 20 parts by mass, the curability of the cured film of the thermosetting composition and the thermal inkjet ink under high temperature and high humidity decreases.

[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) having no functional group reactive with blocked isocyanate has one or more (meth)acryloyl groups in one molecule. Further, the (meth)acryloyl group-containing monomer is a compound having no functional group reactive with isocyanate. The functional group reactive with isocyanate has been described in the compound (B).

[0068] The (meth)acrylates used in the present invention include, for example, 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, 2-phenoxyethyl (meth)acrylate, and bifunctional (meth)acrylates such as 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol diacrylate, trifunctional (meth)acrylates such as trimethylolpropane triacrylate, and polyfunctional (meth)acrylate compounds containing tetrafunctional or higher (meth)acrylates such as ditrimethylolpropane tetraacrylate and dipentaerythritol hexaacrylate. The monomer having the above (meth)acryloyl group may be used alone or in combination of two or more.

[0069] [Gelling agent] The gelling agent according to the present invention is preferably held in a uniformly dispersed state in the cured film cured by light and heat, whereby the penetration of moisture into the cured film can be prevented. Such a gelling agent is preferably at least one compound represented by the following general formula (G1) or (G2) in that it is dispersed in the cured film without inhibiting the curability of the ink. Further, in inkjet printing, it is preferable in that it has good pinning properties, can achieve drawing with both a fine line and film thickness, and has excellent 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 a linear portion of 12 or more carbon atoms and may have a branch.) Since 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, the crystallinity of the gelling agent is further enhanced, the water resistance is improved, and more sufficient space is generated in the following card house structure. Therefore, ink media such as solvents and photopolymerizable compounds are more likely to be sufficiently encapsulated in the above space, and the pinning property of the ink becomes higher.

[0071] Further, the carbon number of the linear or branched hydrocarbon group (alkyl chain) is preferably 26 or less. When it is 26 or less, the melting point of the gelling agent does not increase excessively, so it is not necessary to heat the ink excessively when ejecting the ink.

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

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

[0074] Examples of the ketone wax represented by the general formula (G1) include lignoceryl ketone (C24-C24), dibehenyl ketone (C22-C22), distearyl ketone (C18-C18), dieicosyl ketone (C20-C20), dipalmitoyl ketone (C16-C16), dimyristyl ketone (C14-C14), dilauryl ketone (C12-C12), lauryl myristyl ketone (C12-C14), lauryl palmitoyl ketone (C12-C16), myristyl palmitoyl ketone (C14-C16), myristyl stearyl ketone (C14-C18), myristyl behenyl ketone (C14-C22), palmityl stearyl ketone (C16-C18), palmityl behenyl ketone (C16-C22), stearyl behenyl ketone (C18-C22). The carbon numbers in the parentheses above represent the carbon numbers of the two hydrocarbon groups divided by the carbonyl group respectively.

[0075] Examples of commercially available products of the ketone wax represented by the general formula (G1) include Stearonne (manufactured by Alfa Aeser; stearone), 18-Pentatriacontanon (manufactured by Alfa Aeser), Hentriacontan-16-on (manufactured by Alfa Aeser), and Kao Wax T-1 (manufactured by Kao Corporation).

[0076] Examples of the fatty acid or ester wax represented by the general formula (G2) include behenyl behenate (C21-C22), icosyl icosanoate (C19-C20), stearyl stearate (C17-C18), palmityl stearate (C17-C16), lauryl stearate (C17-C12), cetyl palmitate (C15-C16), palmityl stearate (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), arachidyl linoleate (C17-C20). The carbon numbers in the parentheses above represent the carbon numbers of the two hydrocarbon groups divided by the ester group respectively.

[0077] Examples of commercially available ester waxes represented by the general formula (G2) include Unister M-2222SL and Spam Acechi, manufactured by NOF Corporation (Unister is a registered trademark of the company), Exceparl SS and Exceparl MY-M, manufactured by Kao Corporation (Exceparl 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 Amreps PC, manufactured by Kao Alcohol Industries Co., Ltd. (Amreps is a registered trademark of the company).

[0078] Since these commercially available products are often mixtures of two or more types, they may be separated and purified as necessary and then incorporated into the ink. Among these gelling agents, from the viewpoint of enhancing the pinning property more, ketone wax, ester wax, higher fatty acid, higher alcohol, and fatty acid amide are preferable.

[0079] The content of the gelling agent according to the present invention is preferably in the range of 0.5 to 5.0% by mass based on the total mass of the ink. By setting the content of the gelling agent within the above range, the solubility of the gelling agent in the solvent component and the pinning effect are good, and further, the water resistance when forming a cured film is good. Also, from the above viewpoint, the content of the gelling agent in the inkjet ink is more preferably in the range of 0.5 to 2.5% by mass.

[0080] Further, from the following viewpoints, it is preferable that the gelling agent crystallizes in the ink at a temperature below the gelation temperature of the ink. The gelation temperature refers to the temperature at which, when the ink solubilized or liquefied by heating is cooled, the gelling agent undergoes a phase transition from sol to gel and the viscosity of the ink changes abruptly. Specifically, the solubilized or liquefied ink can be cooled while measuring the viscosity with a viscoelasticity measuring device (for example, MCR300, manufactured by Physica), and the temperature at which the viscosity rises rapidly can be taken as the gelation temperature of the ink.

[0081] [Photoinitiator] When the photopolymerizable compound in the photoinitiator according to the present invention is a radical-polymerizable compound, it is preferable to use a photo radical initiator. When the photopolymerizable compound is a cation-polymerizable compound, it is preferable to use a photoacid generator.

[0082] The photoinitiator may be contained alone or in two or more kinds in the thermosetting inkjet ink of the present invention. The photoinitiator may be a combination of both a photo radical initiator and a photoacid generator.

[0083] The photo radical initiator includes a cleavage-type radical initiator and a hydrogen abstraction-type radical initiator.

[0084] Examples of the cleavage-type radical initiator include acetophenone-based initiators, benzoin-based initiators, acylphosphine oxide-based initiators, benzyl, and methylphenylglyoxy esters.

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

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

[0087] Examples of the acylphosphine oxide-based initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0088] Examples of hydrogen abstraction type radical initiators 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, methyl o-benzoylbenzoate-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-based initiators include 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone.

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

[0092] Examples of photoacid generators include the compounds described on pages 187 to 192 of "Organic Materials for Imaging" edited by the Research Society of Organic Electronics Materials, published by Bunshin Publishing (1993).

[0093] The content of the photopolymerization initiator may be within a range where the ink can be sufficiently cured. For example, it can be in the range of 0.01 to 10% by mass based on 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 A.G.), Genocure EPD (manufactured by Rahn A.G.), etc.

[0095] The ink of the present invention may further contain a photoinitiator assistant, a polymerization inhibitor, etc., if necessary.

[0096] The photoinitiator assistant may be a tertiary amine compound, and an aromatic tertiary amine compound is preferred.

[0097] Examples of the aromatic tertiary amine compound 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, N,N-dimethylhexylamine, etc. Among them, 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] [Colorant] 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 with respect to the components of the ink and excellent weather resistance. The pigment is not particularly limited, and examples thereof include organic pigments or inorganic pigments having the following numbers described in the Color Index.

[0099] Examples of red or magenta pigments include pigments selected from 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, Pigment Orange 13, 16, 20, 36, or mixtures thereof, etc.

[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, 60, or mixtures thereof, etc.

[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, 193, or mixtures thereof, etc.

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

[0104] Examples of commercially available pigments include Black Pigment (manufactured by Mikuni Corporation), Chromophine Yellow 2080, 5900, 5930, AF-1300, 2700L, Chromophine Orange 3700L, 6730, Chromophine Scarlet 6750, Chromophine Magenta 6880, 6886, 6891N, 6790, 6887, Chromophine Violet RE, Chromophine Red 6820, 6830, Chromophine Blue HS-3, 5187, 5108, 5197, 5085N, SR-5020, 5026, 5050, 4920, 4927, 4937, 4824, 4933GN-EP, 4940, 4973, 5205, 5208, 5214, 5221, 5000P, Chromophine Green 2GN, 2GO, 2G-550D, 5310, 5370, 6830, Chromophine Black A-1103, Seika Fast Yellow 10GH, A-3, 2035, 2054, 2200, 2270, 2300, 2400(B), 2500, 2600, ZAY-260, 2700(B), 2770, Seika Fast Red 8040, C405(F), CA120, LR-116, 1531B, 8060R, 1547, ZAW-262, 1537B, GY, 4R-4016, 3820, 3891, ZA-215, Seika Fast Carmine 6B1476T-7, 1483LT, 3840, 3870, Seika Fast Bordeaux 10B-430, Seika Light Rose R40, Seika Light Violet B800, 7805, Seika Fast Maroon 460N, Seika Fast Orange 900, 2900, Seika Light Blue C718, A612, Cyanine Blue 4933M, 4933GN-EP, 4940, 4973 (all of the above are manufactured by Dainichi Seika Chemicals 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 (all of the above are manufactured by DIC Corporation);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, ColortexBlue516, 517, 518, 519, A818, P-908, 510, Colortex Green402, 403, Colortex Black 702, U905 (the above are manufactured by Sanyo Pigment Co., Ltd.); Lionol Yellow1405G, Lionol Blue FG7330, FG7350, FG7400G, FG7405G, ES, ESP-S (the above are manufactured by Toyo Ink Co., Ltd.), Toner Magenta E02, Permanent RubinF6B, Toner Yellow HG, Permanent YellowGG-02, Hostapeam BlueB2G (the above are manufactured by Hoechst Industries); Novoperm P-HG, Hostaperm Pink E, Hostaperm Blue B2G (the above are 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, CF9 (the above are manufactured by Mitsubishi Chemical Corporation), etc. can be mentioned.;

[0105] The dispersion of the pigment can be carried out, for example, by 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 dispersion of the pigment is preferably carried out such that the volume average particle diameter of the pigment particles is preferably in the range of 0.08 to 0.5 μm, and the maximum particle diameter is preferably in the range of 0.3 to 10 μm, more preferably in the range of 0.3 to 3 μm.

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

[0108] The ink of the present invention may further contain a dispersant in order to enhance the dispersibility of the pigment. Examples of the dispersant 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, high-molecular copolymers, modified polyurethanes, modified polyacrylates, polyether ester type anionic surfactants, naphthalene sulfonic acid formalin condensate salts, aromatic sulfonic acid formalin condensate salts, polyoxyethylene alkyl phosphate esters, polyoxyethylene nonylphenyl ethers, and stearylamine acetates. Examples of commercially available products of the dispersant include the Solsperse series of Avecia and the PB series of Ajinomoto Fine-Techno Co., Inc.

[0109] The ink of the present invention may further contain a dispersion aid as needed. The dispersion aid may be selected according to the pigment. The total amount of the dispersant and the dispersion aid is preferably in the range of 1 to 50% by mass based on the pigment.

[0110] The ink of the present invention may further contain a dispersion medium for dispersing a pigment as necessary. Although a solvent may be included in the ink as the dispersion medium, in order to suppress the residue of the solvent 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] Examples of the dye include oil-soluble dyes.

[0112] Examples of the 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.), AIZENSOT 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 Co., 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 Kasei Co., Ltd.), HSR-31, DIARESIN Red K (all manufactured by Mitsubishi Kasei Co., Ltd.), 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, MS Cyan VPG (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, SIRIUS SUPRA TURQ.Blue FB-LL 330% (manufactured by Bayer Japan Co., Ltd.), KAYASET Blue FR, KAYASET Blue N, KAYASET Blue 814, Turq.Blue GL-5 200, Light Blue BGL-5200 (manufactured by Nippon Kayaku Co., Ltd.), DAIWA Blue 7000, OleosolFast Blue GL (manufactured by Daiwa Kasei Co., Ltd.), DIARESIN Blue P (manufactured by Mitsubishi Kasei Corporation), SUDAN Blue 670, NEOPEN Blue 808, ZAPON Blue 806 (manufactured by BASF Japan Ltd.), and the like.

[0114] Examples of yellow dyes include MS Yellow HSm-41, Yellow KX-7, Yellow EX-27 (manufactured by Mitsui Chemicals, Inc.), AIZEN SOT Yellow-1, AIZEN SOT YelloW-3, AIZEN SOT Yellow-6 (manufactured by Hodogaya Chemical Co., Ltd.), MACROLEX Yellow 6G, MACROLEX FLUOR.Yellow 10GN (manufactured by Bayer Japan Co., Ltd.), KAYASET Yellow SF-G, KAYASET Yellow2G, KAYASET Yellow A-G, KAYASET Yellow E-G (manufactured by Nippon Kayaku Co., Ltd.), DAIWA Yellow 330HB (manufactured by Daiwa Kasei Co., Ltd.), HSY-68 (manufactured by Mitsubishi Kasei Corporation), SUDAN Yellow 146, NEOPEN Yellow 075 (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 (both manufactured by Hodogaya Chemical Co., Ltd.), RESORIN Black GSN 200%, RESOLIN Black BS (both manufactured by Bayer Japan Co., Ltd.), KAYASET Black A-N (manufactured by Nippon Kayaku Co., Ltd.), DAIWA Black MSC (manufactured by Daiwa Kasei Co., Ltd.), HSB-202 (manufactured by Mitsubishi Kasei Corporation), NEPTUNE Black X60, NEOPEN Black X58 (both manufactured by BASF Japan Ltd.), and the like.

[0116] The colorant is included in the ink of the present invention, and one kind or two or more kinds may be included, and it may be adjusted 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 with respect to the total amount of the ink.

[0117] [Other Components] 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 can be obtained. These components may be included only one kind or two or more kinds in the ink of the present invention.

[0118] (Polymerization Inhibitor) Examples of the polymerization inhibitor include (alkyl)phenol, hydroquinone, catechol, resorcin, p-methoxyphenol, t-butylcatechol, t-butylhydroquinone, pyrogallol, 1,1-picrylhydrazyl, phenothiazine, p-benzoquinone, nitrosobenzene, 2,5-di-t-butyl-p-benzoquinone, dithiobenzoyldisulfide, picric acid, cupferron, aluminum N-nitrosophenylhydroxylamine, tri-p-nitrophenylmethyl, N-(3-oxyaniolino-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), Genorad 18 (manufactured by Rahn A.G.), and the like.

[0120] The amount of the polymerization inhibitor can be arbitrarily set within the range where the effects of the present invention can be obtained. The amount of the polymerization inhibitor can be, for example, 0.001% by mass or more and less than 1.0% by mass based on the total mass of the ink.

[0121] (Surfactant) Examples of surfactants include anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalene 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 - based 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 GmbH, "BYK" is a registered trademark of the company), and TSF4452 (manufactured by Momentive Performance Materials).

[0123] Fluorine - based surfactants mean those in which some or all of the hydrogen atoms bonded to the carbon atoms of the hydrophobic group of ordinary surfactants are replaced by fluorine. Examples of fluorine-based surfactants include Megafac F, manufactured by DIC Corporation (Megafac is a registered trademark of the company), Surflon, manufactured by AGC Chemicals (Surflon is a registered trademark of the company), Fluorad FC, manufactured by 3M Company (Fluorad is a registered trademark of the company), Monflor, manufactured by Imperial Chemical Industries, Zonyls, manufactured by E.I. du Pont de Nemours and Company, Licowet VPF, manufactured by Rubicon Hoechst, and FTERGENT, manufactured by Neos (FTERGENT is a registered trademark of the company).

[0124] The amount of the surfactant can be arbitrarily set within the range where the effects of the present invention can be obtained. The amount of the surfactant can be, for example, 0.001% by mass or more and less than 1.0% by mass based on the total mass of the ink.

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

[0126] (Coupling agent) In the present invention, various coupling agents may be included as necessary. By including the coupling agent, the adhesion to the copper foil can be improved. Examples of the 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 included as necessary. By including the ion scavenger, there are advantages such as ionic impurities being adsorbed and the insulation property under the condition that the cured film absorbs moisture being improved.

[0128] Examples of the ion scavenger include inorganic ion adsorbents such as triazinethiol 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, although no solvent is preferably used from the viewpoint of curability, it can also be added for adjusting the ink viscosity.

[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 preferably in the range of 1 to 1×10 4 Pa·s, which is preferable in that it sufficiently gels the ink when landing and cooling to room temperature, and the pinning property is good.

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

[0132] Also, 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. When the phase transition point is 40 °C or higher, the ink gels rapidly after landing on the recording medium, so the pinning property becomes higher. Also, when the phase transition point is lower than 100 °C, the ink handling property is good and the ejection stability is high.

[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 in the range of 40 to 60 °C.

[0134] The viscosity of the ink of the present invention at 80°C, the viscosity at 25°C, and the phase transition point 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 method.

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

[0137] The viscosity at 80°C and the viscosity at 25°C can be determined by reading the viscosities at 80°C and 25°C respectively in the viscosity-temperature change curve. The phase transition point can be determined as the temperature at which the viscosity becomes 200 mPa·s in the viscosity-temperature change curve.

[0138] From the viewpoint of further enhancing the ejection property from the inkjet head, the average dispersed particle diameter of the pigment particles according to the present invention is preferably in the range of 50 to 150 nm, and the maximum particle diameter is preferably in the range of 300 to 1000 nm. A more preferable average dispersed particle diameter is in the range of 80 to 130 nm.

[0139] The average dispersed particle diameter of the pigment particles in the present invention means a value obtained by the dynamic light scattering method using a DataSizer Nano ZSP, manufactured by Malvern. Since the ink containing the colorant has a high concentration and light does not pass through this measuring instrument, the ink is diluted 200 times before measurement. The measurement temperature is normal 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 for 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 the penetration of moisture into the solder resist film. As a result, the adhesion at the interface between the copper foil and the solder resist film on the printed circuit board is improved, and copper migration is prevented, suppressing a decrease in insulation performance.

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

[0142] When the ink of the present invention contains a compound having a photopolymerizable functional group and a photoinitiator, it preferably includes a step of irradiating the landed ink with actinic rays to cause temporary curing of the ink ((2) step) between the steps (1) and (3).

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

[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 electro-mechanical conversion methods such as single cavity type, double cavity type, bender type, piston type, shear mode type, and shared wall type, and electro-thermal conversion methods such as thermal inkjet type and bubble jet (registered trademark) (bubble jet is a registered trademark of Canon Inc.).

[0146] By discharging the ink droplets from the inkjet head in a heated state, the discharge stability can be enhanced. The temperature of the ink when discharged is preferably in the range of 40 to 100 °C, and more preferably in the range of 40 to 90 °C in order to further enhance the discharge stability. In particular, it is preferable to perform ejection at an ink temperature such that the viscosity of the ink is in the range of 7 to 15 mPa·s, more preferably in the range of 8 to 13 mPa·s.

[0147] For a sol-gel phase transition type ink, in order to enhance the ejectability of the ink from the inkjet head, the temperature of the ink when filled in the inkjet head is preferably set to (gelation temperature + 10) °C to (gelation temperature + 30) °C of the ink. If the temperature of the ink in the inkjet head is (gelation temperature + 10) °C or higher, the ink will not gel in the inkjet head or on the nozzle surface, and the ejectability of the ink will not decrease. On the other hand, if the temperature of the ink in 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 of heating the ink is not particularly limited. For example, at least any one of an ink supply system such as an ink tank, a supply pipe, and a pre-chamber ink tank immediately before the head that constitute the head carriage, a pipe with a filter, and a piezo head can be heated by a panel heater, a ribbon heater, or warm water.

[0149] The amount of ink droplets when discharged is preferably in the range of 2 to 20 pL from the aspects of recording speed and image quality.

[0150] The printed circuit board is not particularly limited. For example, it may be made of materials such as copper-clad laminates for high-frequency circuits using materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluorine / polyethylene / PPO / cyanate ester, etc. All grades (such as FR-4) of copper-clad laminates, as well as other polyimide films, PET films, glass substrates, ceramic substrates, wafer plates, stainless steel plates, etc. are preferred.

[0151] <Step (2)> In the step (2), the ink landed in the step (1) is irradiated with actinic rays to temporarily cure the ink. The actinic rays can be selected, for example, from electron beams, ultraviolet rays, α-rays, γ-rays, X-rays, etc., but ultraviolet rays are preferably used.

[0152] The irradiation of ultraviolet rays can be performed, for example, using a water-cooled LED manufactured by Phoseon Technology under the condition of a wavelength of 395 nm. By using the LED as a light source, it is possible to suppress the defective curing of the ink due to the ink melting by the radiant heat of the light source.

[0153] The irradiation of ultraviolet rays is preferably performed such that the peak illuminance on the surface of the resist film of ultraviolet rays having a wavelength in the range of 370 to 410 nm is in the range of 0.5 to 10 W / cm 2 more preferably in the range of 1 to 5 W / cm 2 From the viewpoint of suppressing the irradiation of radiant heat to the ink, the amount of light irradiated to the resist film is preferably less than 500 mJ / cm 2

[0154] The irradiation of actinic rays is preferably performed within 0.001 to 300 seconds after the ink lands, and more preferably within 0.001 to 60 seconds in order to form a high-definition resist film.

[0155] <Step (3)> In the step (3), after the temporary curing in the step (2), the ink is further heated to fully cure. ​The heating method is preferably carried out by putting it into an oven set within the range of 110 to 180 °C for 10 to 60 minutes, for example.

[0156] In addition to being used as the ink for forming the solder resist pattern described above, the thermosetting inkjet ink of the present invention can also be used as an adhesive, a sealing agent, a circuit protection agent, etc. for electronic components.

Examples

[0157] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the display of "parts" or "%" is used, and unless otherwise specified, it represents "parts by mass" or "% by mass".

[0158] 《Example 1》 [Preparation of thermosetting compositions 1-1 to 1-44] Each component of 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 was blended in the ratios shown in Tables I to III, and this was stirred with a dissolver to obtain thermosetting compositions 1-1 to 1-44.

[0159] [Preparation of thermosetting compositions 1-45 to 1-58] The components of 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 up 96% by mass of the whole thermosetting composition. The addition ratio thereof is shown in Table III. Further, a photoinitiator and a photoinitiator coagent were each blended in the following amounts, and this was stirred with a dissolver to obtain thermosetting compositions 1-45 to 1-58. Photoinitiator Irgacure TPO (manufactured by BASF): 1.0% by mass Photoinitiator Genocure ITX (manufactured by Rahn A.G.): 3.0% by mass

[0160] [Formation of cured films 1-1 to 1-58] Using this thermosetting composition 1 to 58, a film with a thickness of 30 μm was formed on a BT substrate using an applicator (manufactured by ERICHSEN). The thermosetting compositions 1-1 to 1-44 were cured at 160 °C for 30 minutes to form cured films 1-1 to 1-44. For the thermosetting compositions 1-45 to 1-58, a LED lamp (395 nm, 8W / cm 2 , water cooled unit) manufactured by Phoseon Technology was used to irradiate until it reached 500 mJ / cm 2 to cure the film, and then cured at 160 degrees for 30 minutes to form cured films 1-45 to 1-58.

[0161] The compounds shown in the following table are shown. <Block 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 Sumitomo Bayer Urethane Co., Ltd., blocking agent: MEKO (methyl ethyl ketoxime) oxime-based compound) A-5: Trixene BI7991 (manufactured by LANXESS, biuret type, blocking agent: DMP / DEM) A-6: Desmodur BL 1100 / 1 (manufactured by Sumitomo Bayer Urethane Co., Ltd., blocking agent: ε-caprolactam)

[0162] <Compound (B) having a functional group capable of hydrogen bonding with a block 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 Co., Ltd.) 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] <(Meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with blocked isocyanate> C-1: Dipropylene glycol diacrylate (DPGDA: M222 manufactured by Miwon Co., Ltd.) C-2: TMP(EO)9TA (Trimethylolpropane EO-modified triacrylate) (EM2382 manufactured by Changxing Chemical Industry 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 temperature and the pencil hardness of the cured film were evaluated. [Storage stability at high temperature] After measuring the viscosity of the prepared thermosetting compositions 1-1 to 1-58 at 25°C, they were stored in a sealed container at 85°C for 500 hours, then allowed to cool to 25°C, the viscosity after the high-temperature treatment was measured, the viscosity increase rate (%) was calculated, and evaluation was carried out according to the following criteria. The viscosity was measured using Physica MCR301 (manufactured by Anton Paar) at a shear rate of 1000 (1 / s). The viscosity increase rate (%) = (viscosity after 500 hr. - initial viscosity) / initial viscosity × 100.

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

[0166] [Pencil hardness] For each of the cured films 1-1 to 1-58 formed by thermosetting or thermosetting plus photocuring, a pencil hardness test was measured in accordance with JIS K 5400 using a Mitsubishi Pencil Hi-uni.

[0167] Specifically, the wooden part of the pencil was shaved off and the core was made 5 to 6 mm in length. A pencil with a circular cross-section obtained by smoothly polishing the tip of the core with abrasive paper was used. This pencil was held at an angle of 45 degrees to the sample surface, and with a load of 1 kg applied to the sample surface, the coating film was scratched at an angle of 45 degrees. The maximum hardness of the pencil at which the coating film did not reach the substrate was evaluated.

[0168] [Pencil hardness under high temperature and high humidity] For each of the cured films 1-1 to 1-58 formed by thermosetting or thermosetting plus photocuring, they were left standing for 500 hours under the conditions of 85 °C and 85% relative humidity. Thereafter, the above-described pencil hardness evaluation was carried out in the same manner, and the peeling state of the cured film was observed. The above results are shown in Tables I to III. In the following tables, 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 are respectively denoted as the compound (B) having a functional group capable of hydrogen bonding and the (meth)acryloyl group-containing monomer (C).

[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 clearly materials excellent in storage stability during high-temperature storage, thermosetting properties, and thermosetting properties under high temperature and high humidity. Further, it can be seen that a thermosetting composition containing 1 to 10 parts by mass of the compound (B) having a hydrogen-bondable functional group or 1 to 10 parts by mass of the blocked isocyanate (A) with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C) has further excellent ink storage stability.

[0173] Further, it can be seen that when the compound (B) having a hydrogen-bondable functional group is a (meth)acryloyl group-containing monomer, it is excellent in ink storage stability and pencil hardness. Furthermore, it can be seen that a thermosetting composition irradiated with light using a photoinitiator is excellent in pencil hardness.

[0174] 《Example 2》 [Preparation of Inkjet Ink] <Preparation of Yellow Pigment Dispersion> The following dispersant 1 and dispersant 2 and a dispersion medium were placed in a stainless steel beaker, heated and stirred for 1 hour while heating on a hot plate at 65°C, cooled to room temperature, and then the following pigment was added thereto, and it was put into a glass bottle together with 200 g of zirconia beads having a diameter of 0.5 mm and sealed. This was subjected to dispersion treatment with a paint shaker until a desired particle size was obtained, and then the zirconia beads were removed.

[0175] Dispersant 1: EFKA7701 (manufactured by BASF) 5.6 parts by mass Dispersant 2: Solsperse22000 (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 (manufactured by BASF, Paliotol Yellow D1155) 13.4 parts by mass

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

[0177] Dispersant: EFKA 7701 (manufactured by BASF) 7 parts by mass Dispersion medium: Dipropylene glycol diacrylate (containing 0.2% UV-10) 70 parts by mass Pigment: PB15:4 (manufactured by Dainichi Seika, Chromofine Blue 6332JC) 23 parts by mass

[0178] <Gelling Agent> The following were used as the gelling agent. D-1: Distearyl ketone D-2: Behenyl behenate

[0179] <Photoinitiator> TPO and ITX described in Example 1 were used.

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

[0181] <(Meth)acryloyl Group-Containing Monomer (C) Having No Functional Group Capable of Reacting with Block Isocyanate> C-1 to C-3 described above were used.

[0182] [Preparation of Thermosetting Inkjet Ink] Thermosetting inkjet inks were respectively formulated according to the compositions shown below, stirred with a dissolver, and filtered through a Teflon (registered trademark) 3μm 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" Block isocyanate (A), a compound (B) having a functional group capable of hydrogen bonding, and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the block isocyanate were combined to a total of 93.0 parts by mass of the whole composition. The addition ratio is shown in Tables IV and V. Further, the following components were contained. · Yellow pigment dispersion: 1.0% by mass · Cyan pigment dispersion: 2.0% by mass · Photoinitiator: TPO: 1.0% by mass · Photoinitiator: ITX: 3.0% by mass

[0184] "Preparation of Thermosetting Inkjet Inks 2-42 to 2-56" Block isocyanate (A), a compound (B) having a functional group capable of hydrogen bonding, and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the block isocyanate were combined to a total of 90.0 parts by mass of the whole composition. The addition ratio is shown in Tables V and VI. Further, the following components were contained. · Yellow pigment dispersion: 1.0% by mass · Cyan pigment dispersion: 2.0% by mass · Gelation agent D-1: 2.0% by mass · Gelation agent D-2: 1.0% by mass · Photoinitiator: TPO: 1.0% by mass · Photoinitiator: ITX: 3.0% by mass

[0185] "Preparation of Thermosetting Inkjet Inks 2-57 to 2-62" Block isocyanate (A), a compound (B) having a functional group capable of hydrogen bonding, and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the block isocyanate were combined to a total of 97.0 parts by mass of the whole composition. The addition ratio is shown in Table VI. Further, the following components were contained. · 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" Block isocyanate (A), a compound (B) having a functional group capable of forming a hydrogen bond, and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the block isocyanate were combined to make 94.0 parts by mass in total of the composition. The addition ratio thereof is shown in Table VI. Further, the following components were added. · Yellow pigment dispersion: 1.0 mass% · Cyan pigment dispersion: 2.0 mass% · Gelling agent D-1: 2.0 mass% · Gelling agent D-2: 1.0 mass%

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

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

[0189] The viscosity at 25 °C of the inks containing the gelling agent of the present invention was all 1 to 1×10 4 Pa·s, whereas the inks without the gelling agent were all less than 1 Pa·s. Also, the gel phase transition temperatures of the inks containing the gelling agent of the present invention were all temperatures in the range of 40 to 100 °C, but no gel phase transition phenomenon was observed in the inks without the gelling agent.

[0190] <Pattern Formation by Thermosetting Inkjet Ink> Each of the prepared thermosetting inkjet inks was loaded into an inkjet recording apparatus having an inkjet recording head equipped with a piezo-type inkjet nozzle. Using this apparatus, pattern formation was performed 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, an ink flow path, a sub-ink tank immediately before the inkjet recording head, a pipe with a metal filter, and a piezo head. The ink is heated to 90°C from the ink tank to the head portion. A heater is also built into the piezo head to heat the ink temperature inside the recording head to 90°C. The piezo head has nozzles with a diameter of 22 μm, and the heads 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 became a dot of 6.0 pl, and a solid pattern of 20 mm × 50 mm and a comb pattern with a line & space of 100 μm were printed on the substrate so that each had a thickness of 20 μm. Then, an LED lamp (395 nm, 8W / cm 2 , water cooled unit) manufactured by Phoseon Technology was irradiated at 500 mJ / cm 2 to temporarily cure the ink layer. Thereafter, it was put into an oven set at 150°C for 60 minutes for full curing to obtain a printed sample.

[0193] 《Evaluation》 For each of the above-prepared inkjet inks and the formed coating films, the storage stability of the inkjet ink and the pencil hardness of the formed coating film were evaluated in the same manner as the evaluation method shown in Example 1. The above 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, it is clear that the thermosetting inkjet ink of the present invention is a material excellent in storage stability, and heat and photo-curing properties. Further, it can be seen that the composition in which 1 to 10 parts by mass of the compound (B) having a functional group capable of hydrogen bonding or 1 to 10 parts by mass of the blocked isocyanate (A) is used with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C) has further excellent ink storage stability.

[0198] Further, it can be seen that when the compound (B) having a functional group capable of hydrogen bonding is a specific functional group, the ink storage stability is further improved. This is presumed to be because it has a structure in which hydrogen bonding easily occurs at the blocked site of the blocked isocyanate.

[0199] Further, it can be seen that by adding a gelling agent to the heat and photo-curing composition of the present invention, the ink storage stability and the thermosetting property are further improved.

[0200] The thermosetting composition of the present invention is excellent in storage stability at high temperatures and the thermosetting property of the surface of the cured film under high temperature and high humidity, and can be preferably applied to thermosetting inkjet inks.

Claims

1. A thermosetting composition containing a blocked isocyanate (A), comprising a compound (B) having a functional group capable of hydrogen bonding with the blocked isocyanate (A) and a (meth)acryloyl group-containing monomer (C) having no functional group capable of reacting with the blocked isocyanate, wherein the compound (B) is contained in the range of 0.1 to 20 parts by mass and the blocked isocyanate (A) is contained in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C), and the compound (B) is a polyfunctional (meth)acryloyl group-containing monomer having a hydroxy group Characterized in that it is a thermosetting composition.

2. The thermosetting composition according to claim 1, wherein the compound (B) is 2-hydroxy-3-acryloyloxypropyl methacrylate, dipentaerythritol penta(meth)acrylate, ethylene oxide-added pentaerythritol tetra(meth)acrylate, trimethylolpropane diacrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate propionate, hydroxypivalaldehyde-modified dimethylolpropane tri(meth)acrylate, sorbitol tri(meth)acrylate, sorbitol tetra(meth)acrylate, sorbitol penta(meth)acrylate, pentaerythritol tri(meth)acrylate, or an acrylic-modified product of glycidyl diester of hexahydrophthalic acid.

3. The thermosetting composition according to claim 1, wherein the compound (B) is an alicyclic carboxylic acid-based epoxy acrylate.

4. The thermosetting composition according to any one of claims 1 to 3, characterized in that it contains a photopolymerization initiator.

5. The thermosetting composition according to any one of claims 1 to 4, characterized in that the compound (B) is contained in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the (meth)acryloyl group-containing monomer (C).

6. A thermosetting inkjet ink characterized by containing the thermosetting composition according to any one of claims 1 to 5.

7. The thermosetting inkjet ink according to claim 6, which contains a gelling agent and undergoes a sol-gel phase transition depending on temperature.

8. The viscosity at a temperature of 25°C is in the range of 1 to 1×10 ４ Pa·s, and the thermosetting inkjet ink according to claim 7, characterized in that it undergoes the sol-gel phase transition within the range of a temperature of 40°C or more and less than 100°C.

9. The thermosetting inkjet ink according to claim 7 or claim 8, wherein the gelling agent is a compound having a structure represented by the following general formula (G1) or general formula (G2). General formula (G1): R １ -CO-R ２ General formula (G2): R ３ -COO-R ４ (wherein, R １ ~R ４ each independently represents an alkyl chain having a linear moiety of 12 or more carbon atoms and may have a branch.)

10. The thermosetting inkjet ink according to any one of claims 6 to 9, which is a thermosetting inkjet ink for forming a solder resist pattern used for a printed circuit board.

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