Resist ink, etching method, electronic device

Abstract

To provide resist ink which is excellent in adhesion to a metallic foil and etching resistance even when a baking temperature is set to be lower than a conventional baking temperature (for example, 150°C or lower), a metallic foil etching method using the resist ink, and an electronic apparatus manufactured using the resist ink.SOLUTION: There are provided resist ink which contains an acid group-containing olefin resin (A) having crystallinity and a melting point of 50°C or higher and 150°C or lower and an organic solvent (B); a metallic foil etching method using the resist ink; and an electronic apparatus manufactured using the resist ink.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resist ink used when creating a circuit board or the like from a metal foil, an etching method for the metal foil using the resist ink, and an electronic device manufactured using the resist ink.

Background Art

[0002] As an information management and anti-theft prevention system for products, the "RFID (Radio Frequency Identifier) method" that exchanges information through short-range wireless communication using an electromagnetic field, radio waves, etc. from an IC tag embedded with ID information has become mainstream mainly in European and American countries, and demand is also starting to increase in Japan.

[0003] Such an IC tag generally performs masking printing in a coil shape that becomes a circuit pattern using a resist ink on a metal foil, and after ultraviolet curing or heat curing of the printed portion as needed, it is immersed in an acidic or alkaline etching solution to etch and remove unnecessary portions as a circuit pattern, and create the required circuit pattern (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using a thermosetting type resist ink, baking is usually performed at 170°C to 200°C using an oven. From the viewpoints of energy saving and cost reduction, it is desired to lower the baking temperature. However, if the baking temperature is lowered, there is a risk that the adhesion between the metal foil and the printed film of the resist ink will decrease, or the etching resistance will decrease. Even under the low temperature condition of an oven temperature of 150°C, a resist ink compatible with low-temperature baking that maintains both the adhesion to the metal foil and the etching resistance is desired.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a resist ink having excellent adhesion to a metal foil and etching resistance even when the baking temperature is lower than conventional (for example, 150°C or lower).

Means for Solving the Problems

[0007] The present invention relates to a resist ink containing a crystalline olefin resin (A) having an acid group and having a melting point of 50°C or higher and 150°C or lower, and an organic solvent (B).

Effects of the Invention

[0008] According to the present invention, it is possible to provide a resist ink having excellent adhesion to a metal foil and etching resistance even when the baking temperature is lower than conventional (for example, 150°C or lower).

Modes for Carrying Out the Invention

[0009] <Resist Ink> The resist ink of the present invention contains a crystalline olefin resin (A) having an acid group and having a melting point of 50°C or higher and 150°C or lower, and an organic solvent (B).

[0010] (Olefin Resin (A) Containing Acid Group) Examples of the acid group included in the olefin resin (A) containing an acid group include a carboxyl group, a carboxylic anhydride group, a sulfonic acid group, a phosphoric acid group, and the like. The acid group-containing resin may contain only one of these, or may contain two or more of them.

[0011] Examples of such an acid group-containing olefin resin (A) include a homopolymer or copolymer of an acid group-containing monomer, a copolymer of an acid group-containing monomer and an olefinic monomer, an acid group-containing monomer-modified product of a polyolefin, and the like.

[0012] As the acid group-containing monomer used for preparing a homopolymer or copolymer of an acid group-containing monomer, an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride is preferable. Specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic anhydride, 2-octa-1,3-diketospiro[4.4]non-7-ene, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, norbornene-5-ene-2,3-dicarboxylic anhydride, and the like can be mentioned.

[0013] As the acid group-containing monomer used for preparing a copolymer of an acid group-containing monomer and an olefinic monomer, the same monomers as those used for preparing a homopolymer or copolymer of an acid group-containing monomer described above can be used. They can be used alone or in combination of two or more. It is preferable to use maleic anhydride.

[0014] Examples of the olefinic monomer used for preparing the copolymer of an acid group-containing monomer and an olefinic monomer include olefins having 2 to 8 carbon atoms, such as ethylene, propylene, isobutylene, 1-butene, 4-methyl-1-pentene, hexene, vinylcyclohexane, etc. Among these, olefins having 3 to 8 carbon atoms are preferred because they have particularly good adhesion to metal foil and etching resistance, propylene and 1-butene are more preferred, and in particular, the combined use of propylene and 1-butene is preferred because of its excellent adhesion to metal foil and etching resistance.

[0015] For the preparation of the copolymer of an acid group-containing monomer and an olefinic monomer, in addition to the above-mentioned acid group-containing monomer and olefinic monomer, compounds having other ethylenically unsaturated groups, such as styrene, butadiene, isoprene, etc., may be used in combination.

[0016] As the acid group-containing monomer used for preparing the acid group-containing monomer-modified polyolefin, the same acid group-containing monomers as those used for preparing the homopolymer or copolymer of the above-mentioned acid group-containing monomers can be used. They may be used alone or in combination of two or more. It is preferable to use maleic anhydride.

[0017] Examples of the polyolefin used for preparing the acid group-containing monomer-modified polyolefin include homopolymers and copolymers of olefins having 2 to 8 carbon atoms, copolymers of olefins having 2 to 8 carbon atoms and other monomers, etc. For example, polyethylene such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene resin, polypropylene, polyisobutylene, poly(1-butene), poly(4-methyl-1-pentene), polyvinylcyclohexane, ethylene-propylene block copolymer, ethylene-propylene random copolymer, ethylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-hexene copolymer, propylene-1-butene copolymer and other α-olefin copolymers, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-vinyl acetate-methyl methacrylate copolymer, ionomer resin, etc. Among these, homopolymers of olefins having 3 to 8 carbon atoms and copolymers of two or more olefins having 3 to 8 carbon atoms are preferred in terms of having particularly good adhesion, and homopolymer of propylene or propylene-1-butene copolymer is more preferred, and especially propylene-1-butene copolymer is preferred in terms of excellent adhesion to metal foil and etching resistance.

[0018] Examples of the method for modifying polyolefin with an acid group-containing monomer include graft modification and copolymerization. To react an acid group-containing monomer with polyolefin by graft modification, specifically, methods include melting polyolefin and adding an acid group-containing monomer (graft monomer) thereto for graft reaction, dissolving polyolefin in a solvent to form a solution and adding a graft monomer thereto for graft reaction, mixing polyolefin dissolved in an organic solvent with a graft monomer, and heating at a temperature equal to or higher than the softening temperature or melting point of polyolefin to simultaneously perform radical polymerization and hydrogen abstraction reaction in a molten state, etc.

[0019] In any case, in order to efficiently carry out the graft copolymerization of the graft monomer, it is preferable to carry out the graft reaction in the presence of a radical initiator. The graft reaction is usually carried out under the conditions of 60 to 350°C. The usage ratio of the radical initiator is usually in the range of 0.001 to 1 part by weight with respect to 100 parts by weight of the polyolefin before modification.

[0020] The acid group-containing olefin resin (A) used in the present invention has crystallinity and a melting point of 50°C or higher and 150°C or lower. In this specification, the fact that the acid group-containing olefin resin (A) has crystallinity means that the acid group-containing olefin resin has a melting point and the heat of fusion is 0.1 J / g or more. The melting point of the acid group-containing olefin resin (A1) can be measured by the method described in JIS-K-7121, and the heat of fusion can be measured by the method described in JIS-K-7122.

[0021] From the viewpoint of etching resistance, the melting point of the acid group-containing olefin resin (A) is 50°C or higher, more preferably 60°C or higher, and even more preferably 65°C or higher. Further, from the viewpoint of lowering the baking temperature, the melting point of the acid group-containing olefin resin (A) is 150°C or lower, preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 90°C or lower.

[0022] The acid group-containing olefin resin (A) preferably has a heat of fusion of 1 mJ / mg or more, more preferably 5 mJ / mg or more, preferably 60 mJ / mg or less, and more preferably 45 mJ / mg or less. Thereby, a resist ink excellent in etching resistance can be obtained.

[0023] In order to improve the adhesion to the metal foil and the etching resistance, the weight average molecular weight of the acid group-containing olefin resin (A) is preferably 10,000 or more. Further, in order to ensure appropriate fluidity, the weight average molecular weight of the acid group-containing olefin resin (A) is preferably 200,000 or less. More preferably, it is 50,000 or more and 180,000 or less.

[0024] In the present invention, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are values measured by gel permeation chromatography (GPC) under the following conditions.

[0025] Measuring device: HLC-8320GPC manufactured by Tosoh Corporation Columns: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL manufactured by Tosoh Corporation Detector: RI (differential refractometer) Data processing: Multi-station GPC-8020 model II manufactured by Tosoh Corporation Measurement conditions: Column temperature 40°C Solvent: Tetrahydrofuran Flow rate: 0.35 ml / min Standard: Monodisperse polystyrene Sample: A 0.2 mass% tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (100 μl)

[0026] The acid value of the acid group-containing olefin resin (A1) is preferably 0.1 mgKOH / g or more, more preferably 5 mgKOH / g or more, because it has good adhesion to the metal foil. On the other hand, although it depends on the structure of the olefin chain, when the acid value is high, the molecular weight tends to be small and the crystallinity tends to be low. Therefore, from the viewpoint of etching resistance, it is preferably 50 mgKOH / g or less.

[0027] (Organic solvent (B)) Examples of the organic solvent (B) include aromatic organic solvents such as toluene and xylene; aliphatic organic solvents such as n-hexane and n-heptane; alicyclic organic solvents such as cyclohexane and methylcyclohexane; halogenated organic solvents such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; alcohol solvents such as ethanol, methanol, n-propanol, 2-propanol (isopropyl alcohol), butanol, and hexanol; ether solvents such as diisopropyl ether, butyl cellosolve, tetrahydrofuran, dioxane, and butyl carbitol; glycol ether solvents such as diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, and propylene glycol monomethyl ether; glycol ester solvents such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate. These may be used alone or in combination of two or more.

[0028] Since it has excellent solubility in the acid group-containing olefin resin (A), it is preferable to use a mixed solvent of an alicyclic organic solvent and an ester solvent. It is preferable to use methylcyclohexane as the alicyclic organic solvent and at least one of ethyl acetate and butyl acetate as the ester solvent. Further, a mixed solvent of an alicyclic organic solvent, an ester solvent, and an alcohol solvent may be used to improve the solubility of the acid group-containing olefin resin (A). At this time, isopropyl alcohol, 2-butanol, etc. are preferable as the alcohol solvent.

[0029] In addition, when using an isocyanate compound (C1) as the compound (C) described later, in order to improve the solubility of the isocyanate compound (C1), an aromatic organic solvent or a ketone solvent may be further used in combination with an alicyclic organic solvent and an ester solvent. At this time, toluene is preferably mentioned as the aromatic organic solvent, and methyl ethyl ketone is preferably mentioned as the ketone solvent.

[0030] In addition, when using an epoxy compound (C2) as the compound (C) described later, in order to improve the solubility of the epoxy compound (C2), an aromatic organic solvent or a ketone solvent may be further used in combination with an alicyclic organic solvent and an ester solvent, and it is more preferable to use a ketone solvent in combination. At this time, toluene is preferably mentioned as the aromatic organic solvent, and methyl ethyl ketone is preferably mentioned as the ketone solvent.

[0031] The amount of the organic solvent (B) used is preferably such that the ratio of the acid group-containing olefin resin (A) to the total mass of the acid group-containing olefin resin (A) and the organic solvent (B) is 5 to 30% by mass. Thereby, a resist ink excellent in coatability and wettability to a metal foil can be obtained.

[0032] The reason why the resist ink of the present invention exhibits excellent adhesion to a metal foil and etching resistance even when baked at a low temperature is not clear, but it is presumed as follows. Since the acid group-containing olefin resin (A) has a melting point of 150°C or lower, the acid group-containing olefin resin (A) spreads sufficiently wet on the metal foil during baking. At this time, it is considered that the acid groups move to the metal foil side to make the adhesion between the resist ink and the metal foil stronger. And since the acid group-containing olefin resin (A) has crystallinity and a melting point of 50°C or higher, the coating film of the resist ink is difficult to be wetted by the etching solution, and it is difficult for the etching solution to penetrate into the coating film of the resist ink.

[0033] (Compound (C)) The resist ink of the present invention exhibits sufficiently excellent etching resistance even in the form of a one-component type as described above. However, it may also be a two-component type resist ink used in combination with a compound (C) having a plurality of functional groups capable of reacting with the acid group-containing olefin resin (A). By combining with the compound (C), a resist ink having even more excellent etching resistance can be obtained. When the resist ink of the present invention is of the two-component type, hereinafter, a composition containing the acid group-containing olefin resin (A) and the organic solvent (B) is referred to as the first agent, and a composition containing the compound (C) is referred to as the second agent. The second agent may contain an organic solvent (B'). As the organic solvent (B') used in the second agent, the same solvents as the organic solvent (B) can be used.

[0034] Examples of the compound (C) include an isocyanate compound (C1), an epoxy compound (C2), an aziridine group-containing compound (C3), a carbodiimide group-containing compound (C4), an oxazoline group-containing compound (C5), a hydrazide group-containing compound (C6), an amino resin (C7), and the like.

[0035] The isocyanate compound (C1) is not particularly limited as long as it has a plurality of isocyanate groups in one molecule, and conventionally known ones can be used. Specific examples include aliphatic diisocyanates such as butane-1,4-diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, octamethylene diisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,6,11-undecane triisocyanate, xylylene diisocyanate, m-tetramethylxylylene diisocyanate, lysine diisocyanate, lysine ester triisocyanate,

[0036] Aliphatic diisocyanates such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, norbornane diisocyanate,

[0037] Aromatic diisocyanates such as 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, etc. can be mentioned.

[0038] Compounds derived therefrom, namely, isocyanurate forms, adduct forms, biuret types, uretdione forms, allophanate forms of the above isocyanates, prepolymers having isocyanate residues (low polymers obtained from diisocyanates and polyols), or composites thereof, etc. can also be used.

[0039] A compound obtained by reacting some of the isocyanate groups of the polyfunctional isocyanate compound as described above with a compound having reactivity with an isocyanate group may be used as the isocyanate compound (C1). Examples of the compound having reactivity with an isocyanate group include compounds containing an amino group such as butylamine, hexylamine, octylamine, 2-ethylhexylamine, dibutylamine, ethylenediamine, benzylamine, and aniline; compounds containing a hydroxyl group such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, octanol, 2-ethylhexyl alcohol, dodecyl alcohol, ethylene glycol, propylene glycol, benzyl alcohol, and phenol; compounds having an epoxy group such as allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol glycidyl ether, and cyclohexanedimethanol diglycidyl ether; compounds containing a carboxylic acid such as acetic acid, butanoic acid, hexanoic acid, octanoic acid, succinic acid, adipic acid, sebacic acid, and phthalic acid, and the like.

[0040] Examples of the epoxy compound (C2) include polyglycidyl ether type epoxy resins of aliphatic polyols such as ethylene glycol, propylene glycol, hexanediol, neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol, glycerin, diglycerin, sorbitol, spiroglycol, or hydrogenated bisphenol A; Bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and bisphenol AD type epoxy resin; Aromatic epoxy resins such as novolak type epoxy resins which are glycidyl ethers of phenol novolak resins or cresol novolak resins; Polyglycidyl ethers of polyols which are ethylene oxide or propylene oxide adducts of aromatic polyhydroxy compounds such as bisphenol A, bisphenol F, bisphenol S, and bisphenol AD; Polyether polyol polyglycidyl ether type epoxy resins such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol; Cycloaliphatic type polyepoxy resins such as bis(3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexyl carboxylate; Polyglycidyl ester type epoxy resins of polycarboxylic acids such as propane tricarboxylic acid, butane tetracarboxylic acid, adipic acid, phthalic acid, terephthalic acid or trimellitic acid; Bisepoxy resins of hydrocarbon dienes such as butadiene, hexadiene, octadiene, dodecadiene, cyclooctadiene, α-pinene or vinylcyclohexene; Epoxy resins of diene polymers such as polybutadiene or polyisoprene; Glycidylamine type epoxy resins such as tetraglycidyl diaminodiphenylmethane, triglycidyl para-aminophenol, tetraglycidyl bisaminomethylcyclohexane, diglycidylaniline, tetraglycidyl metaxylylenediamine; Epoxy resins containing heterocycles such as triazine, hydantoin; Examples include rubber-modified epoxy resins having a rubber skeleton (e.g., polybutadiene, acrylonitrile-butadiene rubber, carboxyl group-terminated acrylonitrile-butadiene rubber, etc.) in the resin skeleton and urethane-modified epoxy resins having a urethane bond. These may be used alone or in combination of two or more.

[0041] Examples of the aziridine group-containing compound (C3) include N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, N,N'-toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, trimethylolpropane-tri-β(2-methylaziridine)propionate, bisisophthaloyl-1-2-methylaziridine, tri-1-aziridinylphosphine oxide, tris-1-2-methylaziridinylphosphine oxide, and the like.

[0042] Examples of the carbodiimide group-containing compound (C4) include compounds having a carbodiimide group such as p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), cyclohexane-1,4-bis(methylene-t-butylcarbodiimide), and polycarbodiimide which is a polymer having a carbodiimide group. Polycarbodiimide can be obtained, for example, by a condensation reaction accompanied by decarboxylation of an isocyanate compound. The isocyanate compound used for the synthesis of polycarbodiimide is not particularly limited, and for example, those exemplified as the isocyanate compound (B1) can be used.

[0043] Examples of the oxazoline group-containing compound (C5) include compounds having an oxazoline group such as 2,2'-bis(2-oxazoline), 2,2'-ethylene-bis(4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene-bis(2-oxazoline), and bis(2-oxazolinylcyclohexane) sulfide, and oxazoline group-containing polymers. The oxazoline group-containing polymer is generally obtained by polymerizing addition-polymerizable oxazolines such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, and 2-isopropenyl-2-oxazoline. Other monomers may be copolymerized with the oxazoline group-containing polymer as needed. The polymerization method of the oxazoline group-containing polymer is not particularly limited, and a known polymerization method can be adopted.

[0044] Examples of the hydrazide group-containing compound (C6) include dihydrazides of dicarboxylic acids containing 2 to 10, particularly 4 to 6 carbon atoms, such as adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, and itaconic acid dihydrazide; and aliphatic water-soluble dihydrazines having 2 to 4 carbon atoms, such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, and butylene-1,4-dihydrazine.

[0045] Examples of the amino resin (C7) include melamine resin, benzoguanamine resin, and urea resin.

[0046] These compounds can be used alone or in combination of two or more. When using the compound (C), it is preferable to use the isocyanate compound (C1) and the epoxy compound (C2) from the viewpoints of pot life and baking temperature.

[0047] The compounding amount of compound (C) is appropriately adjusted depending on the compound (C) used. For example, when using an isocyanate compound (C1), it is preferably compounded and used such that the molar ratio of the isocyanate group to the acid group (isocyanate group / acid group) contained in the first agent and the second agent is 0.5 or more and 30 or less.

[0048] Also, when compound (C) is an epoxy compound (C2), the molar ratio of the epoxy group to the acid group (epoxy group / acid group) contained in the first agent and the second agent is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.3 or more, preferably 0.6 or more, and it is preferably compounded and used such that it is 1.5 or less, and preferably compounded and used such that it is 1.3 or less.

[0049] If the compounding amount of compound (C) is too large, unreacted compound (C) may act to reduce the crystallinity of the resist ink coating film, and there is a risk of reducing the etching resistance.

[0050] In any case, when the acid group contained in the acid group-containing olefin resin (A) is an acid anhydride group and the amount of the acid group contained in the first agent is calculated from the acid modification rate, or when the first agent contains an acid anhydride described later and the amount of the acid group contained in the first agent is calculated from the compounding amount of the acid anhydride (when the amount of the acid group contained in the first agent is not actually measured), 1 equivalent of the acid anhydride group is converted to 2 equivalents of the acid group. These values may also be calculated from the isocyanate equivalent, epoxy equivalent, and acid value.

[0051] (Other compound (D)) The resist ink of the present invention can use various additives such as an acid anhydride (D1), a curing accelerator (D2), other resins (D3), a pigment (D4), a plasticizer, a thermoplastic elastomer, a reactive elastomer, a phosphoric acid compound, a silane coupling agent, and an antifoaming agent as necessary. The content of these additives may be appropriately adjusted within a range that does not impair the function of the resist ink of the present invention.

[0052] Examples of the acid anhydride (D1) include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, unsaturated carboxylic acid anhydrides, etc., and one or more of them can be used in combination. More specifically, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyl octadecanedioic acid) anhydride, poly(phenyl hexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hymic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexenedicarboxylic acid anhydride, methylcyclohexenetetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, het acid anhydride, nadic acid anhydride, methyl nadic acid anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, etc. can be mentioned.

[0053] In addition, those obtained by modifying the above-mentioned compounds with glycols may be used as the acid anhydride (D1). Examples of the glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol, etc. Furthermore, copolymer polyether glycols of two or more of these glycols and / or polyether glycols can also be used.

[0054] The blending amount of the acid anhydride (D1) is preferably 0.01 part by mass or more, more preferably 0.8 part by mass or more, based on 100 parts by mass of the acid group-containing olefin resin (A). Also, the blending amount of the acid anhydride (D1) is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 1.5 parts by mass or less, based on 100 parts by mass of the acid group-containing olefin resin (A).

[0055] When the resist ink of the present invention is a two-component type, it is preferable to use a curing accelerator (D2). The curing accelerator (D2) is appropriately selected depending on the compound (C) used. As an example, when the compound (C) is an isocyanate compound (C1), catalysts such as metal-based catalysts, amine-based catalysts, aliphatic cyclic amide compounds, titanium chelate complexes, and organic phosphorus-based compounds can be used.

[0056] Examples of the metal-based catalysts include metal complex-based, inorganic metal-based, and organometallic-based catalysts. Specifically, as the metal complex-based catalysts, acetylacetonate salts of metals selected from the group consisting of Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), Th (thorium), Ti (titanium), Al (aluminum), and Co (cobalt) can be mentioned. For example, iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, zirconia acetylacetonate, etc. can be mentioned. Among these, from the viewpoints of toxicity and catalytic activity, iron acetylacetonate (Fe(acac)3) or manganese acetylacetonate (Mn(acac)2) is preferable.

[0057] Examples of the inorganic metal-based catalysts include catalysts selected from Fe, Mn, Cu, Zr, Th, Ti, Al, Co, etc.

[0058] Examples of the organometallic catalyst include stannous acetate, stannous octoate, stannous oleate, stannous laurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dioctyltin dilaurate, nickel octoate, nickel naphthenate, cobalt octoate, cobalt naphthenate, bismuth octoate, bismuth naphthenate and the like. Among these, preferred compounds are organotin catalysts, and more preferred are stannous octoate and dibutyltin dilaurate.

[0059] Examples of amine catalysts include tertiary amines such as triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N,N,N’,N’-tetramethylethylenediamine, N,N,N’,N’-tetramethylpropylenediamine, N,N,N’,N”,N”-pentamethyldiethylenetriamine, N,N,N’,N”,N”-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N’,N”,N”-pentamethyldipropylenetriamine, N,N,N’,N’-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N,N-dimethyl-N’-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N’-(2-hydroxyethyl)propylenediamine, bis(dimethylaminopropyl)amine, bis(dimethylaminopropyl)isopropanolamine, 3-quinuclidinol, N,N,N’,N’-tetramethylguanidine, 1,3,5-tris(N,N-dimethylaminopropyl)hexahydro-S-triazine, 1,8-diazabicyclo[5.4.0]undecene-7, 1,5-diazabicyclo[4.3.0]nonene-5, N-methyl-N’-(2-dimethylaminoethyl)piperazine, N,N’-dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N,N-dimethylhexanolamine, N-methyl-N’-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)imidazole, 1-(2-hydroxypropyl)imidazole, 1-(2-hydroxyethyl)-2-methylimidazole, 1-(2-hydroxypropyl)-2-methylimidazole, and compounds obtained by converting these tertiary amines into amine salts with phenol, octylic acid, quaternized tetraphenylborate salts, etc.

[0060] Aliphatic cyclic amide compounds include, for example, δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, β-propiolactam, etc. Among these, ε-caprolactam is preferred because of its excellent curing acceleration effect.

[0061] The titanium chelate complex is a compound whose catalytic activity is enhanced by ultraviolet irradiation, and it is preferably a titanium chelate complex having an aliphatic or aromatic diketone as a ligand because of its excellent curing acceleration effect. Further, in the present invention, in addition to aromatic or aliphatic diketones as ligands, those having an alcohol with 2 to 10 carbon atoms are preferred because the effects of the present invention become more remarkable.

[0062] Examples of the organophosphorus compounds include tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-butylphenyl)phosphine, diphenylphosphine, phenylphosphine, etc.

[0063] When the compound (C) is an epoxy compound (C2), examples of the curing accelerator (D2) include organic phosphine compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-butylphenyl)phosphine, diphenylphosphine, and phenylphosphine; imidazole compounds such as 2-methylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole; tertiary amines such as triethylamine, triethylenediamine, N'-methyl-N-(2-dimethylaminoethyl)piperazine, 1,8-diazabicyclo[5.4.0]undecene (DBU), 1,5-diazabicyclo[4.3.0]nonene, and 6-dibutylamino-1,8-diazabicyclo[5.4.0]undecene, and compounds obtained by converting these tertiary amines into amine salts with phenol, octylic acid, quaternized tetraphenylborate salts, etc.; and cationic catalysts such as triallylsulfonium hexafluoroantimonate and diallyliodonium hexafluoroantimonate. These may be used alone or in combination of two or more. It is preferable to use at least one selected from the group consisting of organic phosphine-based compounds and imidazole compounds.

[0064] The blending amount of the curing accelerator (D2) is preferably 0.01 part by mass or more and 5 parts by mass or less, more preferably 0.01 part by mass or more and 1 part by mass or less, and even more preferably 0.01 part by mass or more and 0.5 part by mass or less, based on 100 parts by mass of the acid group-containing olefin resin (A).

[0065] Examples of the other resin (D3) include olefin resins other than the acid group-containing olefin resin (A), rosin-based or rosin ester-based resins, terpene-based or terpene phenol-based resins, saturated hydrocarbon resins, coumarone resins, coumarone indene resins, styrene resins, xylene resins, phenol resins, petroleum resins, and the like. These may be used alone or in combination of two or more. Among them, it is preferable to use a styrene resin.

[0066] Styrene resins include homopolymers of styrene-based monomers such as homopolymers of styrene, homopolymers of α-methylstyrene; copolymers of styrene and α-methylstyrene; copolymers of styrene-based monomers such as styrene and α-methylstyrene and polymerizable aliphatic monomers; copolymers of styrene-based monomers such as styrene and α-methylstyrene and polymerizable aromatic monomers, and the like.

[0067] The styrene resin preferably has a softening point in the range of 80 to 150°C, more preferably in the range of 90 to 145°C. Also, it preferably has a weight average molecular weight in the range of 800 to 3,000. The blending amount of the styrene resin is preferably 0.01 to 1.5 parts by mass with respect to 100 parts by mass of the acid group-containing olefin resin (A).

[0068] Examples of the pigment (D4) include azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, diketopyrrolopyrrole-based, isoindoline-based, and the like. For blue ink, it is preferable to use copper phthalocyanine, and for transparent yellow ink, it is preferable to use C.I.Pigment No Yellow83 from the viewpoints of cost and lightfastness. The colorant is preferably contained in an amount sufficient to ensure the concentration and coloring power of the ink, that is, in a proportion of 1 to 50% by mass based on the total mass of the resist ink. Also, the colorant can be used alone or in combination of two or more.

[0069] Examples of the plasticizer include polyisoprene, polybutene, process oil, etc. Examples of the thermoplastic elastomer include styrene-butadiene copolymer (SBS), hydrogenated styrene-butadiene copolymer (SEBS), SBBS, hydrogenated styrene-isoprene copolymer (SEPS), styrene block copolymer (TPS), olefinic elastomer (TPO), etc. Examples of the reactive elastomer include those obtained by acid-modifying these elastomers.

[0070] Examples of the phosphoric acid compound include phosphoric acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, metaphosphoric acid, etc., condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, ultraphosphoric acid, etc., mono- and diesterified products of orthophosphoric acid and alcohols such as monomethyl orthophosphate, monoethyl orthophosphate, monopropyl orthophosphate, monobutyl orthophosphate, mono-2-ethylhexyl orthophosphate, monophenyl orthophosphate, monomethyl phosphite, monoethyl phosphite, monopropyl phosphite, monobutyl phosphite, mono-2-ethylhexyl phosphite, monophenyl phosphite, di-2-ethylhexyl orthophosphate, diphenyl orthophosphate, dimethyl phosphite, diethyl phosphite, dipropyl phosphite, dibutyl phosphite, di-2-ethylhexyl phosphite, diphenyl phosphite, etc., mono- and diesterified products of condensed phosphoric acid and alcohols, products obtained by adding an epoxy compound such as ethylene oxide, propylene oxide, etc. to the above-mentioned phosphoric acids, epoxy phosphoric esters obtained by adding the above-mentioned phosphoric acids to aliphatic or aromatic diglycidyl ether, etc.

[0071] Examples of the silane coupling agent include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane, γ-mercaptopropyltrimethoxysilane, and the like.

[0072] As the defoaming agent, either silicone-based or non-silicone-based ones can be used. For example, BYK series (BYK-051N / 052N / 053N / 054 / 055 / 057 / 063 / 065 / 066N / 067A / 077 / 081 / 088 / 088A / 141 / 354 / 392 / 1752 / 1790 / 1791 / 1794 / 011 / 012 / 014 / 015 / 017 / 018 / 019 / 021 / 022 / 023 / 024 / 025 / 028 / 038 / 044 / 093 / 094 / 1610 / 1615 / 1650 / 1710 / 1711 / 1730 / 1740 / 1770 / 1780 / 1785 / 1798 / A530 / A555) manufactured by BYK Chemie GmbH, Florens series (AC-202 / 220F / 247 / 253 / 265 / 300 / 300HF / 300VF / 303 / 303HF / 324 / 326F / 901 / 901HF / 902 / 903 / 903HF / 950 / 970MS / 1160 / 1160HF / 1170 / 1170HF / 1190 / 1190HF / 2000 / 2000HF / 2200HF / 2230EF / 2300C, AO-5 / 82 / 98 / 106 / 108 / 108EF) manufactured by Kyoeisha Chemical Co., Ltd., KF-96, FA-630, X-50-1039A, KS-7708, KS-66, KSP-69, X-50-1105G, KS-602A, KSP-600, KS-508 / 530 / 531 / 537 / 538 / 540 manufactured by Shin-Etsu Silicone Co., Ltd., FS Antifoam series (DB-110N / EPL / 025 / 92 / 93 / 1224 / 1233 / 1277 / 013A), SH5507, DK Q1-1247, AFE-1530, SM5572F, SM5571 manufactured by Toray Dow Corning Co., Ltd., AK series (AK-350 / 12500 / 60000), AF98 / 1000, TSA series (TSA750 / 720 / 750S) manufactured by Momentive Performance Materials Inc. etc. can be mentioned.

[0073] These components may be pre-formulated in the first agent or the second agent, or may be added when the first agent and the second agent are mixed.

[0074] The resist ink of the present invention can be prepared by mixing the above-described respective components. The components may be mixed simultaneously. However, when the resist ink is of a two-component type, since it is excellent in stability and workability, it is preferable to premix the components other than compound (C) (second agent) in advance to prepare a premix, and mix compound (C) when using the resist ink.

[0075] <Method for manufacturing a circuit board> The resist ink of the present invention is used as a resist ink for etching a metal foil, typified by the manufacture of a circuit board. A circuit board using the resist ink of the present invention is obtained by etching a laminate having a base material and a metal foil provided with a circuit pattern (mask) formed by the resist ink of the present invention with an acidic etching solution.

[0076] As a method for printing a circuit pattern on a metal foil, known methods such as a gravure printing method, a gravure offset printing method, and a screen printing method can be used. After printing a circuit pattern on a metal foil using the resist ink of the present invention, baking is performed to form a resist ink coating film. There is no problem even if the baking temperature is the same as before, but from the viewpoint of energy saving, it is preferably 35°C to 150°C and 5 minutes to 7 days.

[0077] The baking temperature is preferably 5°C or more higher than the melting point of the acid group-containing olefin resin (A), and preferably 10°C or more higher. Thereby, the resist ink is more likely to wet and spread, the adhesion to the metal substrate is improved, the ratio of the crystallization sites of the resist ink coating film is increased, and the etching resistance can be made good. Further, from the viewpoint of energy saving, for example, the difference between the melting point of the acid group-containing olefin resin (A) and the baking temperature is preferably 30°C or less.

[0078] A circuit pattern may be formed on a laminate having a base material and a metal foil, or after forming a circuit pattern on a metal foil, the metal foil and the base material may be laminated.

[0079] Examples of the metal foil include aluminum foil, copper foil, stainless steel foil, titanium foil, tin foil, etc. From the viewpoints of economy and reliability, it is preferable to use aluminum foil or copper foil. The aluminum foil is not limited to pure aluminum foil and also includes aluminum alloy foil. Specifically, as the aluminum foil, for example, pure aluminum foil or aluminum alloy foil such as 1030, 1N30, 1050, 1100, 8021, 8079, etc. according to the symbol of JIS (AA) can be adopted. The copper foil is not limited to pure copper foil and also includes copper alloy foil. Specifically, as the copper foil, for example, pure copper foil or copper alloy foil such as C1100, C2600, C7025, etc. according to the symbol of JIS (AA) can be adopted. The film thickness of the metal foil is not particularly limited, but it is preferably 5 to 100 μm, and more preferably 12 to 70 μm.

[0080] As the base material, conventionally known ones can be used, and examples include base materials containing polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, liquid crystal polymer, polyether ether ketone (PEEK), polyparaphenylene terephthalamide (PPTA), fluororesin, or fluororesin copolymer. The film thickness of the base material is not particularly limited, but from the viewpoints of flexibility and strength, as an example, it is 15 to 50 μm.

[0081] The metal foil and the base material may be bonded together by an adhesive. Such an adhesive is not particularly limited, and conventionally known adhesives such as epoxy resin-based, urethane resin-based, polyimide, acrylic resin-based, vinyl chloride resin solution-based, etc. can be used. It is preferable to use an adhesive having an adhesive strength between the base material and the metal foil of 3 N / 15 mm or more, and more preferably 4 to 6 N / 15 mm. The thickness of the adhesive layer is not limited, but is preferably about 1 to 10 μm, and more preferably about 3 to 7 μm.

[0082] Etching may be performed according to a conventional method, and examples include acid etching with hydrochloric acid, ferric chloride aqueous solution, etc., and alkaline etching with caustic soda.

[0083] <Electronic device> The resist ink of the present invention can be suitably used for forming circuits of various electronic devices. Examples of the electronic devices include, but are not limited to, inlay antennas for RFID, LED packages, flexible printed circuits (FPC), sheet heaters, and the like.

Examples

[0084] Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited thereto. The blending composition and other numerical values are based on mass unless otherwise specified.

[0085] <Measurement method> (Acid value) In this example, the acid value of the acid group-containing olefin resin (A) was obtained from the calibration curve prepared with a chloroform solution of maleic anhydride using FT-IR (FT-IR4200, manufactured by JASCO Corporation), and the stretching peak of the anhydride ring of maleic anhydride (1780 cm -1 ) in the maleic anhydride-modified polyolefin solution and the stretching peak of the carbonyl group of maleic acid (1720 cm -1 ) were used to calculate the value by the following formula. Unless otherwise specified, the unit is mgKOH / g. In the following formula, the molecular weight of maleic anhydride was 98.06 and the molecular weight of potassium hydroxide was 56.11.

[0086]

Number

[0087] (Melting point) The melting point (°C) of the acid group-containing olefin resin was measured according to JIS-K-7121. The actual measurement conditions are as follows. The peak of the melting peak observed during the temperature increase from -50 °C to 150 °C was taken as the melting temperature. Apparatus: X-DSC7000AS-3DX (manufactured by Hitachi High-Tech Science Corporation) Container: Open-type aluminum container (with cover, manufactured by Hitachi High-Tech Science Corporation) Sample: 3.5 mg Reference: Empty container Atmosphere: Nitrogen gas flow 20 ml / min Measurement temperature: -50°C (held for 10 min) → 10°C / min → 150°C (held for 10 min) → -10°C / min → -50°C (held for 10 min) → 10°C / min → 150°C (held for 10 min)

[0088] <Olefin resin (A) containing acid groups> The non-chlorinated maleic anhydride-modified propylene-butene copolymer shown in Table 1 was used as the olefin resin (A-1) to (A-3) containing acid groups. For the olefin resin (A-3) containing acid groups, no melting peak could be observed.

[0089]

Table 1

[0090] <Compound (C)> The following epoxy compound (C2) was used as the compound (C). (Epoxy compound (C2-1)) Denacol (registered trademark) EX-321L (manufactured by Nagase ChemteX Corporation, trimethylolpropane polyglycidyl ether, epoxy equivalent 130) (Epoxy compound (C2-2)) Epiclon (registered trademark) 860-80SE (manufactured by DIC Corporation, BPA type epoxy resin, epoxy equivalent 240) (Epoxy compound (C2-3)) Epiclon (registered trademark) N-665 (manufactured by DIC Corporation, cresol novolak type epoxy resin, epoxy equivalent 200 - 215)

[0091] <Adjustment of resist ink> (Example 1) 100 parts by mass of the olefin resin (A-1) containing acid groups was dissolved in a solvent (a mixed solvent of methylcyclohexane, butyl acetate, and 2-butanol) to obtain the resist ink of Example 1.

[0092] (Example 2)-(Example 8) The adhesives of Examples 2-8 were prepared in the same manner as in Example 1, except that the components used and their blending amounts were changed as shown in Tables 2 and 3.

[0093] (Comparative Example 1), (Comparative Example 2) The adhesives of Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, except that the components used and their blending amounts were changed as shown in Table 3.

[0094] In addition, the details of the compounds not described above in the table are as follows. (2E4MZ) 2-Ethyl-4-methyl-imidazole (Shikoku Kasei Kogyo Co., Ltd.) (FTR8120) Homopolymer of styrene monomer (manufactured by Mitsui Chemicals, weight average molecular weight 1500, non-volatile content 100% by mass) (YH-306) Trialkyltetrahydrophthalic anhydride (manufactured by Mitsubishi Chemical Corporation) (KBM-403) 3-Glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0095] <Preparation of test pieces> (Test piece 1) The resist inks of the examples and comparative examples were applied to the glossy surface of an aluminum foil with a film thickness of 40 μm at an application amount of 3 g / m 2 (dry), dried at 80°C for 1 minute, and then baked at 75°C for 5 days to obtain Test piece 1.

[0096] (Test piece 2) A protective tape was attached to the non-glossy surface of the aluminum foil of Test piece 1, and a cross cut was made in the resist ink coating film to obtain Test piece 2.

[0097] <Evaluation> The test pieces of the examples and comparative examples were evaluated as follows, and the results were summarized in Tables 2 and 3. (Adhesion) A cellophane tape (manufactured by Nichiban Co., Ltd.) was attached to the resist ink coating film of Test Piece 1, and the state of the resist ink coating film when this was rapidly peeled off was observed and evaluated in the following three stages. 〇: The resist ink coating film did not peel off at all. △: The area of the resist ink coating film remaining on the metal foil was 50% or more. ×: The area of the resist ink coating film remaining on the metal foil was less than 50%.

[0098] (Etching resistance: Appearance) Test Piece 2 was immersed in an acid-resistant tray containing hydrochloric acid solution with a concentration of 20% and a liquid temperature of 45°C for 120 seconds, then washed with water, and the state of the resist ink coating film was observed and evaluated in the following three stages. 〇: The resist ink coating film did not peel off at all. △: The area of the resist ink coating film remaining on the metal foil was 50% or more. ×: The area of the resist ink coating film remaining on the metal foil was less than 50%.

[0099] (Etching resistance: Adhesion) Furthermore, a cellophane tape (manufactured by Nichiban Co., Ltd.) was attached to the resist ink coating film, and the state of the resist ink coating film when this was rapidly peeled off was observed and evaluated in the following three stages. 〇: The resist ink coating film did not peel off at all. △: The area of the resist ink coating film remaining on the metal foil was 50% or more. ×: The area of the resist ink coating film remaining on the metal foil was less than 50%.

[0100]

Table 2

[0101]

Table 3

[0102] As is clear from Tables 2 and 3, the resist ink of the present invention was excellent in adhesion and etching resistance even when baked at a lower temperature than before.

Claims

1. A resist ink for acid etching or alkali etching, comprising a crystalline acid group-containing olefin resin (A) having a melting point of 50°C or higher and 150°C or lower, a weight average molecular weight of 50,000 or higher and 180,000 or lower, a heat of fusion of 1 mJ / mg or higher and 60 mJ / mg or lower, and an acid value of 0.1 mgKOH / g or higher and 50 mgKOH / g or lower, and an organic solvent (B).

2. The resist ink according to claim 1, further comprising a compound (C) having a plurality of functional groups capable of reacting with the acid group-containing olefin resin (A).

3. The resist ink according to any one of claims 1 or 2, wherein the acid group-containing olefin resin (A) contains at least one of a skeleton derived from propylene and a skeleton derived from 1-butene.

4. The resist ink according to claim 2, wherein the compound (C) is at least one selected from the group consisting of an isocyanate compound (C1), an epoxy compound (C2), an aziridine group-containing compound (C3), a carbodiimide group-containing compound (C4), an oxazoline group-containing compound (C5), a hydrazide group-containing compound (C6), and an amino resin (C7).

5. The resist ink according to any one of claims 1 to 4, further comprising an acid anhydride (D1).

6. The resist ink according to any one of claims 1 to 5, further comprising a curing accelerator (D2).

7. A method for etching a circuit, comprising: printing a circuit pattern on a metal foil using the resist ink according to any one of claims 1 to 6; baking the resist ink to form a resist ink coating film; and etching the metal foil using the resist ink coating film as a mask.

8. An electronic device comprising a circuit manufactured by the method according to claim 7.

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