Resin Composition for Protective Agent and Its Use

Abstract

The present invention provides a resin composition for a protective agent which has the characteristics of the conventional protective agent required in the past, and further is used to obtain a protective agent that does not warp. The resin composition for a protective agent of the present invention contains a (meth)acrylic-based photocurable polymer, a thermosetting agent, and a photoinitiator. The (meth)acrylic-based photocurable polymer contains a carboxyl group, a chain aliphatic hydrocarbon group having 12 or more carbon atoms, and an unsaturated double bond, and the glass transition temperature (Tg) of the (meth)acrylic-based photocurable polymer is 20°C or lower.

Description

Technical Field

[0001] The present invention relates to a resin composition for a protective agent and its use, and more specifically, to a resin composition for a protective agent having photopolymerizability that is cured by energy ray irradiation, and a cured product, a solder mask, a circuit board, a substrate for semiconductor packaging, and an electronic device using the resin composition for a protective agent. Background Art

[0002] When performing surface processing such as physical processing such as sandblasting or chemical processing such as etching, protection is performed by forming a film on a part of the surface of the object to be processed. The formed protective film or the coating material used to form the protective film is called a resist, and the resist is mainly used for printed circuit boards for electronic components and semiconductor packaging. The resist is classified into a solder resist, a photoresist, a screen printing resist, an etching resist, a plating resist, etc. according to the method of forming the protective film or the use.

[0003] For example, a solder resist is used for a packaging substrate (substrate for packaging) of a semiconductor package, etc., and the packaging substrate has the following structure: a wiring layer (stacked layer) is laminated on the upper and lower sides of a core layer as a support, and the solder resist is overlapped on the unnecessary soldering parts of the outermost layer.

[0004] For the solder resist, the function of protecting the surface of the object as described above is necessary, and properties such as developability, chemical resistance, photocurability, heat resistance, adhesion, and electrical insulation are required. In addition, various studies have been conducted on the photosensitive resin composition used for the solder resist.

[0005] For example, in Patent Document 1, a photosensitive thermosetting resin composition is proposed, which contains, as essential components, a photopolymerizable compound (A), an epoxy compound (B), a photopolymerization initiator (C), and a diluent (D). The photopolymerizable compound (A) is obtained by reacting a reaction product obtained by reacting an epoxy compound (a) having 3 or more epoxy groups in 1 molecule with an unsaturated monocarboxylic acid (b) and a saturated monocarboxylic acid (c) with a polyanhydride (d). The epoxy compound (B) has 2 or more epoxy groups in 1 molecule. In addition, in Patent Document 2, a photosensitive resin composition is proposed, which contains (A) an adhesive polymer, (B) a photopolymerizable compound having an ethylenic unsaturated bond, (C) a photopolymerization initiator, and (D) a thermosetting agent, and the component (B) includes (B-1) a photopolymerizable compound having a fluorene skeleton and an oxyethylene group or an oxypropylene group in the molecule.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-137328

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-160418 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] With the recent trend of thinning, miniaturization, and cost reduction of electrical equipment, there has been a tendency for the component accommodation space within the housing to be restricted. In semiconductor packages, thinning of the package substrate is also expected. Correspondingly, for example, thinning of the core layer, adoption of a coreless substrate, and single-sided mounting of the solder resist on the package substrate have been carried out.

[0012] In the cross-section of the substrate, when the front surface (one surface) and the back surface (the other surface) are asymmetric, the substrate is prone to warping, which is particularly significant when the solder resist is only applied or adhered to one side. In addition, in the front and back surfaces of the package substrate, since the portions that do not require soldering are not necessarily corresponding, even if the solder resist is included on both the front and back surfaces, it will be asymmetric. Therefore, when the core layer is thinned or made into a coreless substrate, the substrate may sometimes warp.

[0013] Therefore, an object of the present invention is to provide a resin composition for a protective agent that has the characteristics of the conventional protective agent and is used to obtain a substrate that does not warp.

[0014] Means for Solving the Problems

[0015] In order to solve the above problems, the present inventors repeatedly conducted intensive studies and found that the above problems can be solved by using a (meth)acrylic-based photocurable polymer containing a chain aliphatic hydrocarbon group having 12 or more carbon atoms as a photopolymerizable compound and having a glass transition temperature (Tg) of 20°C or lower, thereby completing the present invention.

[0016] That is, the present invention is characterized by the following (1) to (15).

[0017] (1) A resin composition for a protective agent, which contains a (meth)acrylic-based photocurable polymer, a thermosetting agent, and a photoinitiator; in the resin composition for a protective agent, the (meth)acrylic-based photocurable polymer contains a carboxyl group, a chain aliphatic hydrocarbon group having 12 or more carbon atoms, and an unsaturated double bond, and the glass transition temperature (Tg) of the (meth)acrylic-based photocurable polymer is 20°C or lower.

[0018] (2) The resin composition for a protective agent as described in (1) above, wherein the (meth)acrylic-based photocurable polymer is an addition copolymer obtained by reacting a reactive compound containing an ethylenically unsaturated double bond with a (meth)acrylic-based copolymer, and the (meth)acrylic-based copolymer is obtained by copolymerizing at least a (meth)acrylic-based polymerizable compound containing a carboxyl group and a polymerizable compound containing a linear aliphatic hydrocarbon group.

[0019] (3) The resin composition for a protective agent as described in (2) above, wherein the polymerizable compound containing a linear aliphatic hydrocarbon group is a (meth)acrylic acid alkyl ester having 12 to 24 carbon atoms.

[0020] (4) The resin composition for a protective agent as described in (2) or (3) above, wherein the content of the segment derived from the polymerizable compound containing a linear aliphatic hydrocarbon group in the (meth)acrylic-based photocurable polymer is in the range of 10 to 50% by mass.

[0021] (5) The resin composition for a protective agent as described in any one of (1) to (4) above, wherein the acid value of the (meth)acrylic-based photocurable polymer is 50 to 100 mgKOH / g.

[0022] (6) The resin composition for a protective agent as described in any one of (1) to (5) above, wherein the double bond equivalent of the (meth)acrylic-based photocurable polymer is 300 to 1000 g / eq.

[0023] (7) The resin composition for a protective agent as described in any one of (1) to (6) above, wherein the glass transition temperature (Tg) of the cured product obtained by curing the resin composition for a protective agent is 100°C or lower.

[0024] (8) The resin composition for a protective agent as described in any one of (1) to (7) above, which further contains a photopolymerizable compound other than the (meth)acrylic-based photocurable polymer.

[0025] (9) The resin composition for a protective agent as described in any one of (1) to (8) above, which is for a solder resist.

[0026] (10) The resin composition for a protective agent as described in any one of (1) to (9) above, which is for semiconductor packaging.

[0027] (11) A cured product obtained by curing the resin composition for a protective agent as described in any one of (1) to (10) above.

[0028] (12) A solder resist film comprising the resin composition for a protective agent according to any one of the above (1) to (10).

[0029] (13) A circuit board including the solder resist film according to the above (12).

[0030] (14) A substrate for a semiconductor package including the solder resist film according to the above (12).

[0031] (15) An electronic device including the circuit board according to the above (13) or the substrate for a semiconductor package according to the above (14).

[0032] Advantages of the Invention

[0033] According to the resin composition for a protective agent of the present invention, by containing the specific (meth)acrylic acid-based photocurable polymer, it can have the characteristics required for a protective agent, especially chemical resistance, and suppress warping of the cured film. Therefore, it can be preferably used for a thin packaging substrate or the like, and an electronic device with high quality reliability can be obtained. Detailed Description of Embodiments

[0034] Embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be variously modified within the scope of its gist.

[0035] In the present invention, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and the same applies to (meth)acrylate. In addition, "(iso)" means both the case where the group is present and the case where the group is absent, and the case where the group is absent is normal.

[0036] In addition, in this specification, "mass" is synonymous with "weight".

[0037] The resin composition for a protective agent of the present invention contains at least a (meth)acrylic acid-based photocurable polymer, a thermal curing agent, and a photoinitiator. Hereinafter, each component will be described.

[0038] <(Meth)acrylic Acid-Based Photocurable Polymer>

[0039] The (meth)acrylic acid-based photocurable polymer used in the present embodiment is characterized by containing a carboxyl group, a chain aliphatic hydrocarbon group having 12 or more carbon atoms, and an unsaturated double bond, and having a glass transition temperature (Tg) of 20°C or lower.

[0040] In the resin composition for a protective agent of the present invention, the (meth)acrylic photocurable polymer has photocurable unsaturated double bonds. Therefore, in the presence of a photoinitiator, it polymerizes upon irradiation with light energy rays such as ultraviolet rays and becomes a cured product. In addition, since it has a carboxyl group, it can be developed using a developer such as a dilute aqueous alkali solution. Moreover, since the glass transition temperature (Tg) of the (meth)acrylic photocurable polymer is 20°C or lower, the cured product obtained by curing the resin composition for a protective agent of the present invention has appropriate flexibility. Since the (meth)acrylic photocurable polymer can be imparted with hydrophobicity by a chain aliphatic hydrocarbon group having 12 or more carbon atoms in the (meth)acrylic photocurable polymer, the chemical resistance against a water-soluble chemical solution is improved. In addition, the above-mentioned unsaturated double bonds are different from the double bonds in the above-mentioned carboxyl group.

[0041] The (meth)acrylic photocurable polymer of the present embodiment is an addition copolymer obtained by adding a compound having an unsaturated double bond to a (meth)acrylic copolymer. The (meth)acrylic photocurable polymer can be produced, for example, by reacting a (meth)acrylic copolymer (X) with a reactive compound (d) containing an ethylenic unsaturated double bond, and the (meth)acrylic copolymer (X) is obtained by copolymerizing at least a (meth)acrylic polymerizable compound (a) containing a carboxyl group and a polymerizable compound (b) containing a chain aliphatic hydrocarbon group.

[0042] (Meth)acrylic polymerizable compound (a) containing a carboxyl group is a (meth)acrylic monomer that contains a carboxyl group in its molecule and can copolymerize with other polymerizable compounds.

[0043] Examples of the (meth)acrylic polymerizable compound (a) containing a carboxyl group include unsaturated monocarboxylic acids such as (meth)acrylic acid, 2-acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl phthalic acid, and 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid. They can be used alone or in combination of two or more. Among them, from the viewpoint of versatility, (meth)acrylic acid is more preferred.

[0044] The polymerizable compound (b) containing a chain aliphatic hydrocarbon group is a monomer that contains a chain aliphatic hydrocarbon group in its molecule and can copolymerize with other polymerizable compounds.

[0045] The chain aliphatic hydrocarbon group may have a straight chain or a branched chain. The number of carbon atoms in the chain aliphatic hydrocarbon group is 12 or more, preferably 12 to 24, and more preferably 16 to 24. When the number of carbon atoms in the chain aliphatic hydrocarbon group is 12 or more, hydrophobicity can be imparted to the (meth)acrylic-based photocurable polymer, and thus the chemical resistance against water-soluble pharmaceutical solutions is improved.

[0046] Examples of the polymerizable compound (b) containing a chain aliphatic hydrocarbon group include (meth)acrylic acid alkyl esters having 12 to 24 carbon atoms. Examples of the (meth)acrylic acid alkyl ester having 12 to 24 carbon atoms include lauryl (meth)acrylate, cetyl (meth)acrylate, (iso)stearyl (meth)acrylate, docosyl (meth)acrylate, and the like. They may be used alone or in combination of two or more. Among them, (iso)stearyl (meth)acrylate is more preferred.

[0047] By copolymerizing at least the above-mentioned (meth)acrylic-based polymerizable compound (a) containing a carboxyl group and the polymerizable compound (b) containing a chain aliphatic hydrocarbon group, a (meth)acrylic-based copolymer (X) can be obtained. In order to adjust the glass transition temperature (Tg), elastic modulus, and heat resistance of the final target, i.e., the (meth)acrylic-based photocurable polymer, it is preferable to further use other polymerizable compounds (c) (monomers) other than the polymerizable compounds (a) and (b) that can copolymerize with the (meth)acrylic-based polymerizable compound (a) containing a carboxyl group and the polymerizable compound (b) containing a chain aliphatic hydrocarbon group.

[0048] As other polymerizable compounds (c), for example, styrene, α-methylstyrene, o-vinyltoluene, m-vinyltoluene, p-vinyltoluene, p-chlorostyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-vinylbenzyl methyl ether, m-vinylbenzyl methyl ether, p-vinylbenzyl methyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether and other aromatic vinyl compounds can be cited; and (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid n-propyl ester, (meth)acrylic acid isopropyl ester, (meth)acrylic acid n-butyl ester, (meth)acrylic acid isobutyl ester, (meth)acrylic acid sec-butyl ester, (meth)acrylic acid tert-butyl ester, 2-(meth)acrylic acid hydroxyethyl ester, 2-(meth)acrylic acid hydroxypropyl ester, 3-(meth)acrylic acid hydroxypropyl ester, 2-(meth)acrylic acid hydroxybutyl ester, 3-(meth)acrylic acid hydroxybutyl ester, 4-(meth)acrylic acid hydroxybutyl ester, (meth)acrylic acid allyl ester, (meth)acrylic acid benzyl ester, (meth)acrylic acid cyclohexyl ester, (meth)acrylic acid phenyl ester, 2-(meth)acrylic acid methoxyethyl ester, 2-(meth)acrylic acid phenoxypropyl ethyl ester, (meth)acrylic acid methoxydiethylene glycol ester, (meth)acrylic acid methoxydiethylene glycol ester, (meth)acrylic acid methoxypropyl glycol ester, (meth)acrylic acid methoxydipropylene glycol ester, (meth)acrylic acid isobornyl ester, (meth)acrylic acid dicyclopentadiene ester, (meth)acrylic acid norbornene ester, 2-hydroxy-3-(meth)phenoxypropyl acrylate, (meth)acrylic acid glycerol monoester and other unsaturated carboxylic acid esters, etc. They can be used alone or in combination of two or more. Among them, styrene and (meth)acrylic acid n-butyl ester are preferably used.

[0049] The polymerizable compound (a) containing a carboxyl group in the (meth)acrylic acid series is preferably formulated so that the acid value of the final target, i.e., the (meth)acrylic acid-based photocurable polymer, is 50 to 100 mgKOH / g.

[0050] The polymerizable compound (b) containing a linear aliphatic hydrocarbon group is preferably formulated so that the content of the segment derived from the polymerizable compound (b) containing a linear aliphatic hydrocarbon group in the final target, i.e., the (meth)acrylic acid-based photocurable polymer, is 10 to 50% by mass.

[0051] When the total weight of the final target substance, i.e., the (meth)acrylic photocurable polymer, is 100% by mass, the formulation amount of the other polymerizable compound (c) is the difference obtained by subtracting the total mass percentage of the (meth)acrylic polymerizable compound (a) containing a carboxyl group, the polymerizable compound (b) containing a linear aliphatic hydrocarbon group, and the reactive compound (d) containing an ethylenically unsaturated double bond from 100% by mass. Additionally, the other polymerizable compound (c) is preferably a compound such that the glass transition temperature (Tg) of the (meth)acrylic photocurable polymer is 20°C or lower.

[0052] The (meth)acrylic copolymer (X) is obtained by mixing the (meth)acrylic polymerizable compound (a) containing a carboxyl group with the polymerizable compound (b) containing a linear aliphatic hydrocarbon group, and optionally mixing in the other polymerizable compound (c) as desired, and reacting them at a reaction temperature of 80 to 130°C, preferably 100 to 120°C, for a reaction time of 5 to 10 hours, preferably 6 to 8 hours.

[0053] Alternatively, when curing the resin composition for a protective agent of the present invention to obtain a cured product, within the range not impairing the properties of the cured product, a thermal polymerization initiator, a polymerization solvent, a chain transfer agent, etc. can be incorporated into the reaction.

[0054] As a thermal polymerization initiator, for example, 2,2-azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), azobiscyanovaleric acid, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2'-azobis(2-methylpropamidine) dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropamidine] hydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(1-imino-1-pyrrolidin-2-yl-2-methylpropane) dihydrochloride, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] and other azo compounds can be cited; and organic peroxides such as tert-butyl peroxytrimethylacetate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide, etc. They can be used alone or in combination of two or more.

[0055] The addition amount of the thermal polymerization initiator is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, and still more preferably 10 to 15% by mass based on the total mass of the monomers to be copolymerized. In addition, the thermal polymerization initiator can be added all at once or in several portions.

[0056] Regarding the polymerization solvent, it is not particularly limited as long as it can dissolve each monomer to be polymerized, the polymer precursor to be formed, and the polymerization initiator and other additives as needed. As the polymerization solvent, for example, methanol, ethanol, isopropanol, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, ethyl acetate, ethyl lactate, methyl lactate, dimethyl sulfoxide, etc. can be used. They can be used alone or in combination of two or more.

[0057] As a chain transfer agent, for example, methanethiol, tert-butyl mercaptan, decyl mercaptan, decylthiol, benzyl mercaptan, lauryl mercaptan, stearyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, thioglycolic acid, thiopropionic acid and its esters, 2-mercaptoethanol, octyl thioglycolate and other mercaptans; methanol, ethanol, propanol, n-butanol, isopropanol, tert-butanol, hexanol, benzyl ethanol, allyl alcohol and other alcohols; chloroethane, fluoroethane, trichloroethylene and other halogenated hydrocarbons; acetone, methyl ethyl ketone, cyclohexanone, acetophenone, acetaldehyde, propionaldehyde, n-butyraldehyde, furfural, benzaldehyde and other carbonyl compounds; and methyl-4-cyclohexene-1,2-dicarboxylic anhydride, α-methylstyrene, α-methylstyrene dimer and the like. They can be used alone or in combination of two or more.

[0058] The reactive compound (d) having an ethylenically unsaturated double bond is a monomer capable of introducing a group having an unsaturated double bond into the copolymer by reacting with the (meth)acrylic copolymer (X). As the reactive compound (d) having an ethylenically unsaturated double bond, for example, a monomer having an ethylenically unsaturated double bond group and a reactive group such as an epoxy group (cyclic ether) or a hydroxyl group in the molecule can be cited.

[0059] The reactive compound (d1) having an ethylenically unsaturated double bond and an epoxy group (cyclic ether) is added to the (meth)acrylic copolymer (X) by a condensation reaction (esterification reaction) of the hydroxyl group generated by the ring opening of the cyclic ether with the carboxyl group of the (meth)acrylic copolymer (X).

[0060] As the reactive compound (d1) having an ethylenically unsaturated double bond and an epoxy group, for example, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate and the like can be cited. They can be used alone or in combination of two or more. Among them, from the viewpoint of versatility, glycidyl methacrylate is preferred.

[0061] The reactive compound (d2) having an ethylenically unsaturated double bond and a hydroxyl group is added to the (meth)acrylic copolymer (X) by a condensation reaction (esterification reaction) of the hydroxyl group with the carboxyl group of the (meth)acrylic copolymer (X).

[0062] As the reactive compound (d2) having an ethylenically unsaturated double bond and a hydroxyl group, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-(meth)phenoxypropyl acrylate and the like can be cited. They can be used alone or in combination of two or more. Among them, from the viewpoint of versatility, 2-hydroxyethyl (meth)acrylate is preferred.

[0063] The reactive compound (d) containing an ethylenically unsaturated double bond is preferably formulated such that the double bond equivalent of the final product, i.e., the photocurable polymer based on (meth)acrylic acid, is 300 to 1000 g / eq.

[0064] In the addition reaction of the reactive compound (d) containing an ethylenically unsaturated double bond to the (meth)acrylic copolymer (X), the carboxyl group of the (meth)acrylic copolymer (X) reacts with the reactive group of the reactive compound (d) containing an ethylenically unsaturated double bond. However, for example, there is a risk that in a nitrogen atmosphere, the polymerization reaction of the (meth)acrylate moiety of the reactive compound (d) containing an ethylenically unsaturated double bond may occur. Therefore, from the viewpoint of suppressing the progress of the polymerization reaction, the addition reaction of the reactive compound (d) containing an ethylenically unsaturated double bond to the (meth)acrylic copolymer (X) is preferably carried out in an air atmosphere.

[0065] The photocurable polymer based on (meth)acrylic acid is obtained by mixing the (meth)acrylic copolymer (X) with the reactive compound (d) containing an ethylenically unsaturated double bond and reacting them at a reaction temperature of 90 to 120 °C, preferably 100 to 110 °C, for a reaction time of 5 to 30 hours, preferably 10 to 20 hours.

[0066] In addition, a reaction accelerator, a solvent, a polymerization inhibitor, etc. can also be incorporated into the reaction.

[0067] As the reaction accelerator, for example, benzyl dimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, 2-methylimidazole, 2-phenylimidazole, triphenylphosphine, diphenylphosphine, phenylphosphine, tetraphenylphosphonium tetraphenylborate, and triphenylphosphine triphenylphosphine, etc. can be used. Among them, from the viewpoint of stability, triphenylphosphine is preferred. These reaction accelerators can be used alone or in combination of two or more.

[0068] The solvent is not particularly limited. For example, methanol, ethanol, isopropyl alcohol, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, ethyl acetate, ethyl lactate, methyl lactate, and dimethyl sulfoxide, etc. can be used. They can be used alone or in combination of two or more.

[0069] Examples of the polymerization inhibitor include phenothiazine, trinonylphenyl phosphite, di(p-fluorophenyl)amine, diphenylpicrylhydrazyl, N-(3-N-hydroxyanilino-1,3-dimethylbutylidene)aniline oxide, benzoquinone, hydroquinone, methoxyphenol, butylcatechol, nitrobenzene, picric acid, diphenyl disulfide sulfide, cupferron, and copper(II) chloride. Among them, methoxyphenol is preferably used from the viewpoint of the polymerization inhibition effect. These polymerization inhibitors may be used alone or in combination of two or more.

[0070] In the present embodiment, the content of the segment derived from the polymerizable compound (b) containing a chain aliphatic hydrocarbon group in the (meth)acrylic photocurable polymer is preferably 10 to 50% by mass. When the content of the segment derived from the polymerizable compound (b) containing a chain aliphatic hydrocarbon group is 10% by mass or more, the (meth)acrylic photocurable polymer can be imparted with hydrophobicity, and thus the chemical resistance to a water-soluble chemical solution can be improved. When it is 50% by mass or less, it does not become overly hydrophobic and does not adversely affect the developability. Regarding the content of the segment derived from the polymerizable compound (b) containing a chain aliphatic hydrocarbon group, more preferably, it is 10 to 40% by mass, and further preferably 20 to 30% by mass.

[0071] The content of the segment derived from the polymerizable compound (b) containing a chain aliphatic hydrocarbon group in the (meth)acrylic photocurable polymer can be obtained by calculation based on the content ratio of each monomer component used in the synthesis.

[0072] In the present embodiment, for example, by using acrylic acid as the polymerizable compound (a) containing a carboxyl group in the (meth)acrylic acid series, isooctyl acrylate as the polymerizable compound (b) containing a chain aliphatic hydrocarbon group, butyl acrylate and styrene as the other polymerizable compound (c), and glycidyl methacrylate as the reactive compound (d) containing an ethylenic unsaturated double bond, an acrylated acrylate (a (meth)acrylic photocurable polymer) containing an isooctyl acrylate copolymer acid group can be obtained.

[0073] Specifically, first, acrylic acid, isooctyl acrylate, butyl acrylate, and styrene are mixed at an arbitrary formulation ratio within the above range and reacted to obtain a copolymer. By mixing the obtained copolymer with glycidyl methacrylate at an arbitrary formulation ratio within the above range and reacting them, the cyclic ether in glycidyl methacrylate is ring-opened and undergoes an addition reaction with a part of the carboxyl groups in the segment derived from acrylic acid in the copolymer, and glycidyl methacrylate is added to the copolymer by an esterification reaction, thereby obtaining an acrylated acrylate (addition copolymer) containing an isooctyl acrylate copolymer acid group.

[0074] In this embodiment, the glass transition temperature (Tg) of the (meth)acrylic photocurable polymer is 20°C or lower. When the Tg is 20°C or lower, the elongation rate of the cured product becomes high and flexibility is imparted, so warping can be suppressed. The Tg is preferably 10°C or lower, more preferably 5°C or lower. The lower limit is not particularly limited, but when the Tg is too low, the viscosity (tackiness) of the film before curing formed from the resin composition for the protective agent of the present invention becomes strong and handling becomes difficult, so it is preferably -20°C or higher, more preferably -10°C or higher. The adjustment of the Tg of the (meth)acrylic photocurable polymer can be carried out by adjusting the formulation ratio, chemical structure, and crosslinking degree of each component when obtaining the (meth)acrylic copolymer (X), etc.

[0075] In addition, regarding the glass transition temperature (Tg), the Tg can be measured by thermal analysis of the (meth)acrylic photocurable polymer, or it can be simply obtained as a theoretical value by calculation based on the glass transition temperatures of the respective monomer components used in the synthesis. In the case of obtaining the Tg (theoretical Tg) based on the theoretical value, it can be calculated using the FOX formula.

[0076] Furthermore, in this embodiment, the acid value of the (meth)acrylic photocurable polymer is preferably 50 to 100 mgKOH / g. When the acid value is 50 mgKOH / g or more, it is preferable because development can be carried out in a short time, and when it is 100 mgKOH / g or less, it is preferable because curing shrinkage is less.

[0077] In addition, the acid value can be measured based on the method described in JIS K0070.

[0078] Furthermore, in this embodiment, the double bond equivalent of the (meth)acrylic photocurable polymer is preferably 300 to 1000 g / eq. When the double bond equivalent is 300 g / eq or more, the influence of curing shrinkage can be reduced, so it is preferable, and when it is 1000 g / eq or less, the double bonds react sufficiently by irradiation with light energy rays, so excellent resolution can be obtained, so it is preferable.

[0079] Furthermore, in this embodiment, the weight average molecular weight (Mw) of the (meth)acrylic photocurable polymer is preferably 10000 to 50000. When the weight average molecular weight (Mw) is 10000 or more, the film properties after curing become good, so it is preferable, and when it is 50000 or less, the developability becomes good, so it is preferable.

[0080] In addition, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) (for example, "HLC-8220GPC" manufactured by Tosoh Corporation).

[0081] <Thermosetting agent>

[0082] The thermosetting agent used in this embodiment can be a conventionally known thermosetting agent and is not particularly limited. Examples of the thermosetting agent include epoxy resins, carbodiimide resins, amino resins, and the like.

[0083] Examples of the epoxy resin include bisphenol A type epoxy resins, modified derivatives of bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins and other bisphenol type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins and other novolac type epoxy resins, and modified derivatives of novolac type epoxy resins, biphenyl type epoxy resins, epoxy resins containing a naphthalene ring, alicyclic epoxy resins, epoxy resins having a triazine skeleton, dicyclopentadiene type epoxy resins, etc. From the viewpoint of adhesion, bisphenol type epoxy resins and modified derivatives of bisphenol type epoxy resins are preferred. From the viewpoint of heat resistance, novolac type epoxy resins, modified derivatives of novolac type epoxy resins, and alicyclic epoxy resins are preferred.

[0084] Examples of the carbodiimide resin include blocked carbodiimide resins obtained by capping with an amino group that can liberate a carbodiimide group in a polycarbodiimide resin or a carbodiimide compound by heating, cyclic carbodiimide resins, etc. From the viewpoint of storage stability, blocked carbodiimide resins are preferred.

[0085] Examples of the amino resin include melamine resins, benzoguanamine resins, and the like.

[0086] As the thermosetting agent, among the above thermosetting agents, epoxy resins and carbodiimide resins are preferred from the viewpoints of heat resistance and insulation.

[0087] The usage amount of the thermosetting agent is preferably 0.9 to 1.3 equivalents relative to the carboxyl group of the (meth)acrylic-based photocurable polymer. When the thermosetting agent is 0.9 equivalent or more relative to the carboxyl group of the (meth)acrylic-based photocurable polymer, the (meth)acrylic-based photocurable polymer can be sufficiently cured. When it is 1.3 equivalents or less, the remaining thermosetting agent that does not participate in the curing is difficult to remain.

[0088] <Photopolymerization initiator>

[0089] The photopolymerization initiator is a component that promotes the curing reaction by irradiation with energy rays. Examples of the energy rays include visible light, ultraviolet rays, X-rays, electron beams, etc. In this embodiment, ultraviolet rays are preferably used.

[0090] The photoinitiator is not particularly limited. For example, any one of acylphosphine oxide-based photoinitiators, alkyl phenyl ketone-based photoinitiators, intramolecular hydrogen abstraction type photoinitiators, etc. can be used. Among them, from the viewpoints of reactivity and curing uniformity, acylphosphine oxide-based photoinitiators and alkyl phenyl ketone-based photoinitiators are preferred. Specifically, as acylphosphine oxide-based photoinitiators, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,2-dimethoxy-1,2-diphenylethane-1-one core, methyl phenylglyoxylate, etc. can be cited. As alkyl phenyl ketone-based photoinitiators, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one core, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, etc. can be cited. Among them, from the viewpoints of higher radical generation efficiency and deep curing property, 2,4,6-trimethylbenzoyl diphenylphosphine oxide is preferred.

[0091] The content of the photoinitiator is preferably 2 to 20 parts by mass, more preferably 6 to 14 parts by mass, based on 100 parts by mass of the (meth)acrylic acid-based photocurable polymer. When the content of the photoinitiator is 2 parts by mass or more based on 100 parts by mass of the (meth)acrylic acid-based photocurable polymer, the curing reactivity becomes good, and there is a tendency for the long-term reliability to increase. When it is 20 parts by mass or less, it does not cause embrittlement of the cured film, etc., and does not impair the adhesion to the circuit board.

[0092] In the resin composition for the protective agent of the present invention, desired additives can be added within the range that does not impair the effects of the present invention. For example, polymerizable compounds other than the (meth)acrylic acid-based photocurable polymer, colorants, fillers, flame retardants, dispersants, surface modifiers (leveling agents, defoaming agents), and other resins, etc. can be cited.

[0093] <Polymerizable Compounds Other than the (Meth)Acrylic Acid-Based Photocurable Polymer of the Present Invention>

[0094] As an example of the polymerizable compound other than the (meth)acrylic acid-based photocurable polymer of the present invention for this embodiment, as long as it can initiate a crosslinking reaction by light, it is not particularly limited. From the viewpoint of versatility, monomers or polymers having an ethylenically unsaturated bond in the molecule are preferably used.

[0095] Examples of monomers having an ethylenically unsaturated bond in the molecule include (meth)acrylate compounds, bisphenol A-based di(meth)acrylate compounds, epoxy acrylate compounds, modified epoxy acrylate compounds, fatty acid-modified epoxy acrylate compounds, amine-modified bisphenol A-type epoxy acrylate compounds, hydrogenated bisphenol A-based di(meth)acrylate compounds, di(meth)acrylate compounds having a urethane bond in the molecule, (meth)acrylate compounds having a hydrophobic skeleton in the molecule, polyalkylene glycol di(meth)acrylate compounds having both a (poly)ethylene oxide chain and a (poly)propylene oxide chain in the molecule, trimethylolpropane di(meth)acrylate compounds, and polyester acrylate compounds, etc. They can be used alone or in combination of two or more.

[0096] Examples of commercially available monomers having an ethylenically unsaturated bond in the molecule, which are preferably used in the present embodiment, include "EBECRYL-3708", "EBECRYL-1039", and "EBECRYL-230" (all are trade names, manufactured by Daicel-allnex Co., Ltd.), etc.

[0097] The content of the photopolymerizable compound is preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass, relative to 100 parts by mass of the (meth)acrylic-based photocurable polymer. When the content of the photopolymerizable compound is 10 parts by mass or more relative to 100 parts by mass of the (meth)acrylic-based photocurable polymer, the resolution in manufacturing a circuit board can be improved, and thus a finer circuit pattern can be drawn. When it is 60 parts by mass or less, the cured film will have flame retardancy and heat resistance, so it is preferred.

[0098] Examples of polymers having an ethylenically unsaturated bond in the molecule include acid-modified polyether-based urethane acrylate, acid-modified polycarbonate-based urethane acrylate, acid-modified polyester-based urethane acrylate, acid-modified epoxy acrylate, and acid-containing acrylated acrylate, etc. They can be used alone or in combination of two or more.

[0099] The content of the polymer having an ethylenically unsaturated bond in the molecule is preferably less than 100 parts by mass, more preferably less than 80 parts by mass, relative to 100 parts by mass of the (meth)acrylic-based photocurable polymer. When the content of the polymer having an ethylenically unsaturated bond in the molecule is less than 100 parts by mass relative to 100 parts by mass of the (meth)acrylic-based photocurable polymer, there will be no warping of the cured film and the chemical resistance will not be impaired, so it is preferred.

[0100] (Colorant)

[0101] Examples of the colorant used in this embodiment include organic pigments and inorganic pigments.

[0102] Examples of the organic pigments include isoindoline-based, phthalocyanine-based, quinacridone-based, benzimidazolone-based, dioxazine-based, indanthrone-based, perylene-based, azo-based, quinophthalone-based, anthraquinone-based, aniline-based, and cyanine-based organic pigments.

[0103] Examples of the inorganic pigments include carbon black, titanium black, ultramarine, Prussian blue, chrome yellow, zinc chrome, red lead, iron oxide red, zinc oxide, lead white, lithopone, and titanium dioxide.

[0104] They can be used alone or in combination of two or more. Among them, from the viewpoints of colorfastness and insulation, organic pigments are preferably used.

[0105] Regarding the colorant, it is preferably used as a dispersion. The dispersion can be prepared by the following method: the colorant and a dispersant are premixed, and the resulting composition is added to an organic solvent (or vehicle), and dispersed therein. The so-called vehicle refers to the part of the medium that disperses the pigment when the coating is in a liquid state, including the liquid part that combines with the above pigment to fix the coating film (binder), and the component that dissolves and dilutes it (organic solvent).

[0106] Regarding the colorant used in this embodiment, from the viewpoint of dispersion stability, a colorant having a number average particle diameter of 0.001 to 0.1 μm is preferred, and more preferably, a colorant having a particle diameter of 0.01 to 0.08 μm. In addition, the so-called "particle diameter" as mentioned herein refers to the diameter when the electron microscope photograph image of the particle is regarded as a circle of the same area. In addition, the so-called "number average particle diameter" refers to the average value of the above particle diameters obtained for a large number of particles, which is the average value of 100 of them.

[0107] The content of the colorant is preferably 0.1 to 5 parts by mass, more preferably 1 to 3 parts by mass, based on 100 parts by mass of the (meth)acrylic-based photocurable polymer. When the content of the colorant is less than 0.1 part by mass, the energy rays tend to be reflected from the circuit board during patterning, resulting in a tendency to cause defects such as halos. When it exceeds 5 parts by mass, the exposure light does not reach the bottom of the film during photocuring, and uncured parts are generated inside the film. During etching, erosion of the cured film may be caused, resulting in poor pattern formation (poor developability). Therefore, the above range is preferred.

[0108] (Filler)

[0109] Examples of the filler used in this embodiment include ceramic fine particles such as alumina, cordierite, and zircon, and filler components such as barium sulfate, talc, silica, titanium oxide, alumina, and calcium carbonate.

[0110] The content of the filler is preferably 20 to 200 parts by mass, more preferably 50 to 150 parts by mass, relative to 100 parts by mass of the (meth)acrylic-based photocurable polymer. When the content of the filler is within the above range, it is difficult to affect the resolution.

[0111] (Flame retardant)

[0112] As the flame retardant used in this embodiment, for example, phosphorus-based flame retardants, metal hydroxides, etc. can be cited. Among them, from the viewpoint of flame retardancy, phosphorus-based flame retardants are preferred. Phosphorus-based flame retardants are, for example, compounds containing at least 1 phosphorus element in the molecule, and are not particularly limited. For example, red phosphorus, condensed phosphate ester-based compounds, cyclic organophosphorus-based compounds, phosphazene-based compounds, phosphorus-containing (meth)acrylate-based compounds, phosphorus-containing epoxy-based compounds, phosphorus-containing polyol-based compounds, phosphorus-containing amine-based compounds, ammonium polyphosphate, melamine phosphate, metal hypophosphite salts, etc. can be cited. They can be used alone or in combination of two or more.

[0113] The content of the flame retardant is preferably 20 to 60 parts by mass, more preferably 30 to 50 parts by mass, relative to 100 parts by mass of the (meth)acrylic-based photocurable polymer. When the content of the flame retardant is within the above range, flame retardancy can be exerted, and other various properties will not be affected.

[0114] (Dispersant)

[0115] As the dispersant, for example, epoxy silane, (meth)acrylic silane, and wetting dispersants can be cited.

[0116] (Surface conditioner)

[0117] As the surface conditioner, for example, silicone resin-based additives, fluororesin-based additives, and commercially available surfactants can be cited.

[0118] The photocurable resin composition of this embodiment can be produced by a conventionally well-known method and is not particularly limited. For example, it can be produced by successively mixing a photoinitiator, a thermal curing agent, and other optional components into the (meth)acrylic-based photocurable polymer. In addition, in the mixing process when mixing fillers, flame retardants, etc., a mixer such as a bead mill or a roll mill can be used for mixing.

[0119] <Cured product>

[0120] Regarding the resin composition for a protective agent of the present invention, it can be cured by irradiating energy rays to obtain a cured product (cured film) with a desired thickness.

[0121] When curing the resin composition for a protective agent, the resin composition for a protective agent formed into a desired shape is applied. Specifically, the resin composition for a protective agent is applied so as to have a predetermined dry thickness on the surface of a substrate or the like, and a resin layer is formed. After drying it, it can be cured by irradiating energy rays. The energy rays are not particularly limited, and active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams can be used. However, from the viewpoint of efficiently performing the curing reaction, ultraviolet rays are preferably used.

[0122] As a light source for ultraviolet rays, a light source capable of emitting ultraviolet rays (UV) can be used. As a light source for ultraviolet rays, for example, a metal halide lamp, a high-pressure mercury lamp, a xenon lamp, a mercury-xenon lamp, a halogen lamp, a pulsed xenon lamp, and an LED (Light Emitting Diode) can be cited.

[0123] The glass transition temperature (Tg) of the cured product obtained by curing the resin composition for a protective agent of the present invention is preferably 100°C or lower. When the glass transition temperature of the cured product is 100°C or lower, warping can be suppressed. The glass transition temperature is preferably 90°C or lower, more preferably 80°C or lower. The lower limit is not particularly limited, but when the glass transition temperature is too low, the viscosity (tackiness) of the cured product becomes strong, and there may be a case where the workability becomes difficult. Therefore, it is preferably 40°C or higher, more preferably 50°C or higher.

[0124] In addition, the glass transition temperature (Tg) can be measured by dynamic viscoelasticity measurement (DMA) (for example, "RSA-G2" (trade name) manufactured by TA Instruments Japan Inc.).

[0125] As the film thickness in the case of forming a cured film, for example, it can be set to 5 to 100 μm. In order to be used as a material for electronic devices such as an image display device, a thickness of 10 to 50 μm is preferred.

[0126] <Other uses>

[0127] As preferred uses other than electronic device materials for the resin composition for a protective agent, for example, solder resist inks, solder resist films, etc. can be cited. The resin composition for a protective agent of the present invention can be favorably used as a solder resist film, and this solder resist film is used for a circuit board or a substrate for semiconductor packaging.

[0128] (Solder resist film)

[0129] The solder mask of the present invention includes a support and a photocurable resin composition layer for a protective agent formed on the support, and the resin composition layer for a protective agent contains the resin composition for a protective agent of the present embodiment. The solder mask may also have a protective film layer on the surface of the resin composition layer for a protective agent opposite to the support.

[0130] Hereinafter, a method for manufacturing the solder mask will be described.

[0131] Regarding the resin composition layer for a protective agent, it is preferably formed in the following manner: The resin composition for a protective agent of the present embodiment is dissolved in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, and propylene glycol monomethyl ether, or a mixed solvent thereof. After making a solution having a solid content of about 30 to 70% by mass, the above solution is applied to the support.

[0132] Examples of the support include polymer films having heat resistance and solvent resistance such as polyethylene terephthalate and other polyesters, polypropylene, and polyethylene. It is preferable to perform a release treatment on the surface of the support to which the resin composition is to be applied.

[0133] The thickness of the support can be appropriately selected according to the use and the thickness of the resin composition layer for a protective agent.

[0134] The thickness of the resin composition layer for a protective agent varies depending on the use, but in terms of the thickness after drying by removing the solvent by heating and / or blowing hot air, it is preferably 5 to 100 μm, and more preferably 10 to 50 μm.

[0135] Examples of the protective film include a polyethylene film, a polypropylene film, and polyethylene terephthalate.

[0136] The solder mask of the present invention can be used for circuit protection of a flexible printed wiring board, an interlayer adhesive for a semiconductor package substrate, and circuit protection.

[0137] The protective agent pattern can be manufactured, for example, by a manufacturing method including the following steps: a lamination step of laminating the solder mask on a substrate for circuit formation; an exposure step of irradiating active light to a predetermined portion of the resin composition layer for a protective agent of the solder mask to form a cured portion in the resin composition layer for a protective agent; a development step of removing the resin composition layer for a protective agent other than the cured portion; and a heat curing step of curing the resin composition layer for a protective agent of the cured portion by heating.

[0138] In addition, when the solder mask has a protective film, there is a step of removing the protective film from the solder mask before the lamination step.

[0139] The substrate for circuit formation includes an insulating layer and a conductor layer formed on the insulating layer by an etching method or a printing method (a layer made of a conductive material such as copper, copper-based alloy, silver, silver-based alloy, nickel, chromium, iron, and iron-based alloys such as stainless steel. Preferably made of copper or a copper-based alloy), and is laminated in a lamination process such that the resin composition for the protective agent of the solder mask is located on the side of the conductor layer of the substrate for circuit formation.

[0140] As a method for laminating the solder mask in the lamination process, for example, a method of laminating by pressing the resin composition layer for the protective agent against the substrate for circuit formation while heating it can be cited. In the case of laminating in this way, from the viewpoints of adhesion and followability, etc., it is preferable to laminate under reduced pressure.

[0141] In the lamination process, the heating of the photocurable resin composition layer is preferably carried out at a temperature of 30°C or higher and less than 80°C, the pressing pressure is preferably set to about 0.1 to 2.0 MPa, and the ambient air pressure is preferably set to 3 hPa or less.

[0142] In the exposure process, actinic rays are irradiated to a predetermined portion of the resin composition layer for the protective agent to form a cured portion. As a method for forming the cured portion, a method of irradiating actinic rays in an image shape by passing actinic rays through a negative or positive mask pattern called an art work can be cited. In addition, exposure based on a direct drawing method without a mask pattern such as the LDI method or the DLP (Digital Light Processing) exposure method can also be carried out. At this time, when the support existing on the resin composition layer for the protective agent is transparent, actinic rays can be directly irradiated. When the support is opaque, after removing the support, actinic rays are irradiated to the resin composition layer for the protective agent.

[0143] As a light source for actinic rays, known light sources can be used, such as a carbon arc lamp, a mercury vapor arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, and a semiconductor laser, etc., which can effectively emit ultraviolet rays. In addition, a floodlight bulb for photography, a sun lamp, etc., which can effectively emit visible light, can also be used.

[0144] Next, when there is a support on the resin composition layer for the protective agent, after removing the support, in the developing process, the photocurable resin composition layer other than the cured portion is removed by wet development, dry development, etc. and developed to form a protective agent pattern.

[0145] In the case of wet development, a developer such as an alkaline aqueous solution can be used, and development can be carried out by known methods such as spraying, rocking immersion, brushing, and scraping. As the developer, a developer that is preferably safe, stable, and has good operability is used, for example, a dilute solution of sodium carbonate (1 to 5% by mass aqueous solution) at 20 to 50°C.

[0146] Regarding the protective agent pattern obtained by the above forming method, for example, in the case of being used as a solder resist film of a printed wiring board, a heat curing process is carried out after the development process.

[0147] As the heating method, heating using an oven can be cited. As the heating conditions, it is preferably carried out at a temperature of 80°C or higher for 20 to 120 minutes.

[0148] (Printed Wiring Board)

[0149] According to the above method, a printed wiring board (including a substrate for semiconductor packaging and a flexible printed wiring board) in which a wiring pattern made of a conductive material and a solder resist film are sequentially formed on an insulating layer can be obtained.

[0150] (Electronic Device)

[0151] The electronic device of the present invention includes the above circuit board having a solder resist film or a substrate for semiconductor packaging.

[0152] Examples

[0153] Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited thereto. In addition, in the examples, "parts" and "%" mean mass basis.

[0154] (Synthesis Example 1: Synthesis of (meth)acrylic acid-based photocurable polymer (A))

[0155] 20.6 parts of acrylic acid, 9.0 parts of styrene, 37.4 parts of butyl acrylate, 10 parts of isostearyl acrylate, 80 parts of 1-methoxy-2-propanol, and 3.0 parts of 2,2'-azobisisobutyronitrile (hereinafter referred to as AIBN) were mixed into a flask including a stirrer, a dropping funnel, a condenser, and a thermometer, and stirred at 110°C for 7 hours in a nitrogen atmosphere. Then, in the atmosphere (oxygen concentration 7% or more), after mixing 23.0 parts of glycidyl methacrylate (hereinafter referred to as GMA), 0.04 part of methoxyphenol, and 0.24 part of triphenylphosphine (hereinafter referred to as TPP), stirring was carried out at 100°C. The reaction was terminated at the time point (15 hours) when the acid value reached 90 mgKOH / g by the neutralization titration method using potassium hydroxide. Then, cooling was carried out, and 1-methoxy-2-propanol was added so that the non-volatile component became 40%.

[0156] The weight average molecular weight of the obtained (meth)acrylic photocurable polymer (A) (acrylated acrylate containing isostearyl acrylate copolymer acid group) was measured by gel permeation chromatography (GPC) (standard substance: polyethylene glycol - polyethylene oxide), and the result was 23,000. In addition, the content of isostearyl acrylate (hereinafter referred to as ISTA) as the content of the segment derived from ISTA was 10%, the theoretical value of the glass transition temperature (theoretical Tg) was 0 °C, the theoretical value of the double bond equivalent was 610 g / eq, and the carboxyl equivalent calculated from the acid value was 622 g / eq.

[0157] (Synthesis Example 2: Synthesis of (meth)acrylic photocurable polymer (B))

[0158] Except that in Synthesis Example 1, the input amounts of the raw materials were set to 0.1 part of styrene, 36.4 parts of butyl acrylate, and 20 parts of isostearyl acrylate, the same settings were made, and thus (meth)acrylic photocurable polymer (B) (acrylated acrylate containing isostearyl acrylate copolymer acid group) was obtained.

[0159] The weight average molecular weight (Mw) of this (meth)acrylic photocurable polymer (B) was 23,000, the content of the segment derived from ISTA was 20%, the theoretical value of the glass transition temperature (theoretical Tg) was -7.5 °C, the theoretical value of the double bond equivalent was 610 g / eq, and the carboxyl equivalent calculated from the acid value was 622 g / eq.

[0160] (Synthesis Example 3: Synthesis of (meth)acrylic photocurable polymer (C))

[0161] Except that in Synthesis Example 1, the input amounts of the raw materials were set to 9.4 parts of styrene, 27.0 parts of butyl acrylate, and 20 parts of isostearyl acrylate, the same settings were made, and thus (meth)acrylic photocurable polymer (C) (acrylated acrylate containing isostearyl acrylate copolymer acid group) was obtained.

[0162] The weight average molecular weight (Mw) of this (meth)acrylic photocurable polymer (C) was 21,500, the content of the segment derived from ISTA was 20%, the theoretical value of the glass transition temperature (theoretical Tg) was 5.8 °C, the theoretical value of the double bond equivalent was 610 g / eq, and the carboxyl equivalent calculated from the acid value was 622 g / eq.

[0163] (Synthesis Example 4: Synthesis of (meth)acrylic photocurable polymer (D))

[0164] Except in Synthesis Example 1 where the amounts of raw materials were set to 0.1 part of styrene, 10.3 parts of butyl acrylate, and 46 parts of isostearyl acrylate, the same settings were made to obtain a (meth)acrylic photocurable polymer (D) (acrylated acrylate containing an isostearyl acrylate copolymer acid group).

[0165] The weight average molecular weight (Mw) of the (meth)acrylic photocurable polymer (D) was 25,000, the content of the segment derived from ISTA was 46%, the theoretical value of the glass transition temperature (theoretical Tg) was 5.0 °C, the theoretical value of the double bond equivalent was 610 g / eq, and the carboxyl equivalent calculated from the acid value was 622 g / eq.

[0166] (Synthesis Example 5: Synthesis of (meth)acrylic photocurable polymer (E))

[0167] Except in Synthesis Example 1 where the amounts of raw materials were set to 21.0 parts of styrene and 25.4 parts of butyl acrylate, the same settings were made to obtain a (meth)acrylic photocurable polymer (E) (acrylated acrylate containing an isostearyl acrylate copolymer acid group).

[0168] The weight average molecular weight (Mw) of the (meth)acrylic photocurable polymer (E) was 27,000, the content of the segment derived from ISTA was 10%, the theoretical value of the glass transition temperature (theoretical Tg) was 18.0 °C, the theoretical value of the double bond equivalent (theoretical Tg) was 610 g / eq, and the carboxyl equivalent calculated from the acid value was 622 g / eq.

[0169] (I) Preparation of photosensitive resin composition (resin composition for protective agent)

[0170] Each component was prepared at the formulation ratios shown in Table 1 and mixed with a stirrer to obtain the photosensitive resin compositions of Examples 1 to 8 and Comparative Examples 1 to 3.

[0171] (ii) Preparation of dry film

[0172] The photosensitive resin composition obtained in the above (i) was coated on a 25-μm-thick polyethylene terephthalate (PET) film (supporting PET film), and after drying to a thickness of 25 μm, a polyethylene film was adhered to the side coated with the photosensitive resin composition to obtain a dry film.

[0173] 1. Measurement of glass transition temperature (Tg)

[0174] (1) Preparation of test film

[0175] Peel the polyethylene film from the dry film produced in the above (ii), and bond a 38-μm-thick release-treated polyethylene terephthalate (PET) film (release PET film) to the photosensitive resin composition layer side of the photosensitive resin film composed of the support PET film and the photosensitive resin composition layer by vacuum lamination (manufactured by Meiki Seisakusho Co., Ltd., "MVLP-500 / 600-II" (equipment name)). The vacuum lamination is carried out at a hot plate temperature of 50 to 70 °C, a pressing pressure of 0.5 to 1.0 MPa, a pressing time of 10 to 20 seconds, and a vacuum degree of 3 hPa or less. After the vacuum lamination, irradiate ultraviolet rays of 100 mJ / cm 2 from the release PET film side with an ultra-high pressure mercury lamp. After the irradiation, peel the release PET film, and spray a 1 wt% sodium carbonate aqueous solution at 30 °C on the photosensitive resin composition layer at a spraying pressure of 0.18 MPa for 60 seconds for development. After the development, irradiate ultraviolet rays of 1,000 mJ / cm 2 on the photosensitive resin composition layer with a high pressure mercury lamp. After the irradiation, cure at 180 °C for 120 minutes with a hot air circulation dryer. After the curing, peel the support PET film to obtain a test film.

[0176] (2) Measurement method

[0177] Measure the glass transition temperature (Tg) of the test film by dynamic viscoelastic measurement (DMA) (manufactured by TA Instruments Japan Inc., "RSA-G2" (equipment name)). The results are shown in Table 1.

[0178] 2. Evaluation of chemical resistance (flux resistance)

[0179] (1) Preparation of test specimens

[0180] Peel the polyethylene film from the dry film produced in the above (ii), and bond a 35-μm electrolytic copper foil treated with the chemical solution CZ manufactured by Mec Co., Ltd. to the photosensitive resin composition layer of the photosensitive resin film composed of the support PET film and the photosensitive resin composition layer by vacuum lamination (manufactured by Meiki Seisakusho Co., Ltd., "MVL-500 / 600-II" (equipment name)). The vacuum lamination is carried out at a hot plate temperature of 50 to 70 °C, a pressing pressure of 0.5 to 1.0 MPa, a pressing time of 10 to 20 seconds, and a vacuum degree of 3 hPa or less. After the vacuum lamination, irradiate ultraviolet rays of 100 mJ / cm 2 from the support PET film side with an ultra-high pressure mercury lamp. After the irradiation, peel the support PET film, and spray a 1 wt% sodium carbonate aqueous solution at 30 °C on the photosensitive resin composition layer at a spraying pressure of 0.18 MPa for 60 seconds for development. After the development, irradiate with a high pressure mercury lamp at 1,000 mJ / cm2 Ultraviolet rays. After irradiation, curing is carried out at 180 °C for 120 minutes using a hot air circulation dryer to obtain the test object to be inspected.

[0181] (2) Test method

[0182] Measure the solder flux manufactured by Senju Metal Industry Co., Ltd. (product number: sparkle flux WF-6317) so that it is 0.1 g per unit area (25 cm 2 ) on the entire side surface of the photosensitive resin composition layer of the test object to be inspected, and uniformly coat the solder flux on the entire side surface of the photosensitive resin composition layer of the test object to be inspected. After coating, it is passed through a conveyor belt type reflow oven set at a condition where the object temperature can be maintained at 260 °C for 20 seconds. Then, the solder flux is removed by natural cooling at room temperature and washing with running water. After wiping off the surface moisture with a dry cloth, wipe the side surface of the photosensitive resin composition layer of the test object to be inspected with a waste cloth soaked in ethanol, and visually confirm whether there is a protective agent attached to the waste cloth. The test object with no protective agent attached to the waste cloth is evaluated as "○ (has chemical resistance)", and the test object with a protective agent attached to the waste cloth is evaluated as "× (has no chemical resistance)". The results are shown in Table 1.

[0183] 3. Evaluation of warping

[0184] (1) Preparation of the test object to be inspected

[0185] Peel the polyethylene film from the dry film produced in the above (ii), and bond a 12 μm electrolytic copper foil to the photosensitive resin composition layer of the photosensitive resin film composed of a supporting PET film and a photosensitive resin composition layer by vacuum lamination (manufactured by Meiki Seisakusho Co., Ltd., "MVL pair 500 / 600-II" (equipment name)). The vacuum lamination is carried out at a hot plate temperature of 50 - 70 °C, a pressing pressure of 0.5 - 1.0 MPa, a pressing time of 10 - 20 seconds, and a vacuum degree of 3 hPa or less. After vacuum lamination, irradiate 100 mJ / cm 2 of ultraviolet rays from the side of the supporting PET film. After irradiation, peel the supporting PET film, and spray a 1 wt% sodium carbonate aqueous solution at 30 °C on the photosensitive resin composition layer with a spraying pressure of 0.18 MPa for 60 seconds for development. After development, irradiate 1,000 mJ / cm 2 of ultraviolet rays on the photosensitive resin composition layer with a high-pressure mercury lamp. After irradiation, curing is carried out at 180 °C for 120 minutes using a hot air circulation dryer to obtain the test object to be inspected.

[0186] (2) Test method

[0187] With the photosensitive resin composition layer placed on the upper side, the test object was placed on the table in a test chamber set at a temperature of 23°C and a humidity of 50% and left there. After 24 hours, the state of the test object was observed and evaluated according to the following criteria. The results are shown in Table 1.

[0188] 〔Evaluation Criteria〕

[0189] ○(Good): The end of the test object did not detach from the table at all.

[0190] Δ(Fair): The end of the test object detached from the table. The detachment distance was less than 10 mm, which was a level without practical problems.

[0191] ×(Poor): The end of the test object detached from the table. The detachment distance was 10 mm or more, which was a level with problems in use.

[0192] Table 1

[0193]

[0194] Note)

[0195] (A): Acrylated acrylate containing isostearyl acrylate copolymer acid group (1): Mw = 23,000, acid value = 90 mg KOH / g, ISTA ratio 10%

[0196] (B): Acrylated acrylate containing isostearyl acrylate copolymer acid group (2): Mw = 23,000, acid value = 90 mg KOH / g, ISTA ratio 20%

[0197] (C); Acrylated acrylate containing isostearyl acrylate copolymer acid group (3): Mw = 21,500, acid value = 90 mg KOH / g, ISTA ratio 20%

[0198] (D): Acrylated acrylate containing isostearyl acrylate copolymer acid group (4): Mw = 25,000, acid value = 90 mg KOH / g, ISTA ratio 46%

[0199] (E): Acrylated acrylate containing isostearyl acrylate copolymer acid group (5): Mw = 27,000, acid value = 90 mg KOH / g, ISTA ratio 10%

[0200] (F): "(ACA)-Z250" (trade name) manufactured by Daicel-allnex Co., Ltd., acid-containing acrylated acrylate: Mw = 22,000, acid value 69 mg KOH / g

[0201] (G): Manufactured by Nippon Kayaku Co., Ltd., [ZFR-1491Hj (trade name), carboxylic acid-modified bisphenol F type epoxy acrylate: Mw = 11,000, acid value 98 mg KOH / g

[0202] (H): A urethane acrylate containing an ester bond and an unsaturated bond in the main chain, Mw = 10,000, acid value: 50 mg KOH / g

[0203] (I): "EBECRYL-3708" (trade name) manufactured by Daicel-allnex Co., Ltd., Mw 1,500, bifunctional

[0204] (J): "JER1001" (trade name) manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, epoxy equivalent 475

[0205] (K): Blocking of castor oil-based diol-based polycarbodiimide with an amine dissociating at 110°C (equivalent 440 g / eq, bifunctional)

[0206] (L): 2,4,6-Trimethylbenzoyl diphenylphosphine oxide

[0207] (M): "SC2050-MB" (trade name) manufactured by Admatechs Co., Ltd., silica with an average particle size of 0.5 μm

[0208] (N): Metal hypophosphite

[0209] (0): Isoindoline (yellow pigment)

[0210] According to the results in Table 1, Examples 1 to 8 all have chemical resistance and can suppress warping. In particular, there is no warping in the test specimens of Examples 1 to 7, which is relatively excellent. In contrast, Comparative Examples 1 to 2 cannot suppress warping, and Comparative Example 3 has insufficient chemical resistance. From these results, it can be seen that the resin composition for a protective agent of the present invention can balance chemical resistance and suppression of warping.

[0211] Although the present invention has been described in detail with reference to specific embodiments, those skilled in the art should clearly understand that various changes or modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application filed on August 1, 2018 (Japanese Patent Application No. 2018-145361), and its content is incorporated herein by reference.

Claims

1. A resin composition for a protective agent, which contains a (meth)acrylic photocurable polymer, a thermal curing agent, and a photopolymerization initiator; In this resin composition for a protective agent, the (meth)acrylic photocurable polymer contains a carboxyl group, a linear aliphatic hydrocarbon group having 12 or more carbon atoms, and an unsaturated double bond; the glass transition temperature Tg of the (meth)acrylic photocurable polymer is 20°C or lower, and the glass transition temperature Tg of the cured product obtained by curing the resin composition for a protective agent is 40°C or higher and 100°C or lower.

2. The resin composition for a protective agent according to claim 1, wherein the (meth)acrylic photocurable polymer is an addition copolymer obtained by reacting a reactive compound containing an ethylenically unsaturated double bond with a (meth)acrylic copolymer, and the (meth)acrylic copolymer is obtained by copolymerizing at least a (meth)acrylic polymerizable compound containing a carboxyl group and a polymerizable compound containing a linear aliphatic hydrocarbon group.

3. The resin composition for a protective agent according to claim 2, wherein the polymerizable compound containing a linear aliphatic hydrocarbon group is a (meth)acrylic alkyl ester having 12 to 24 carbon atoms.

4. The resin composition for a protective agent according to claim 2 or 3, wherein the content of the segment derived from the polymerizable compound containing a linear aliphatic hydrocarbon group in the (meth)acrylic photocurable polymer is in the range of 10 to 50% by mass.

5. The resin composition for a protective agent according to any one of claims 1 to 3, wherein the acid value of the (meth)acrylic photocurable polymer is 50 to 100 mgKOH / g.

6. The resin composition for a protective agent according to any one of claims 1 to 3, wherein the double bond equivalent of the (meth)acrylic photocurable polymer is 300 to 1000 g / eq.

7. The resin composition for a protective agent according to any one of claims 1 to 3, which further contains a photopolymerizable compound other than the (meth)acrylic photocurable polymer.

8. The resin composition for a protective agent according to any one of claims 1 to 3, which is for a solder resist.

9. The resin composition for a protective agent according to any one of claims 1 to 3, which is for semiconductor encapsulation.

10. The resin composition for a protective agent according to claim 1, wherein, It further contains a colorant.

11. The resin composition for a protective agent according to claim 1, wherein, The thermal curing agent is a bisphenol A type epoxy resin or a carbodiimide resin.

12. A cured product obtained by curing the resin composition for a protective agent according to any one of claims 1 to 11.

13. A solder resist film containing the resin composition for a protective agent according to any one of claims 1 to 11.

14. A circuit board including the solder resist film according to claim 13.

15. A substrate for semiconductor encapsulation including the solder resist film according to claim 13.

16. An electronic device including the circuit board according to claim 14 or the substrate for semiconductor encapsulation according to claim 15.

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