TWI791791B - Curable resin composition, dry film, cured product and printed wiring board - Google Patents

Abstract

The object of the present invention is to provide a non-electrolyzable non-electrolyzable film after hardening, which can maintain the original characteristics such as excellent developability and resolution, and does not cause problems such as deterioration of dryness to the touch (tack-free). It is a hardening resin composition with excellent tin-plating resistance, as well as excellent adhesion to various substrates, soldering heat resistance, moisture resistance, chemical resistance, electrical insulation and other characteristics of the cured film pattern. The means to solve the problem is a curable resin composition characterized by containing: (A) carboxyl group-containing resin, (B) photopolymerization initiator, (C) thermosetting compound, (D) photopolymerizable monomer , and (E) a polyester having both an aromatic structure and a polyether structure.

Description

Curable resin composition, dry film, cured product and printed wiring board

The present invention relates to curable resin compositions, dry films and cured products suitable for forming coatings such as solder resists of printed wiring boards. Curable resin composition, dry film and cured product of cured coating pattern with excellent drying (tack-free), resolution, electroless tin plating resistance and soldering heat resistance. Moreover, this invention relates to the printed wiring board which formed the permanent film, such as a solder resist layer, by the hardened|cured material of this composition.

Conventionally, in printed wiring boards, curable resin compositions that can be developed by aqueous alkali solutions have been widely used as materials for forming permanent film patterns such as solder resist layers by exposure and development. For example, a curable resin composition is exemplified, which includes: a carboxyl group-containing resin in which a polybasic acid anhydride is added to a reaction product of a novolak type epoxy resin and an unsaturated monocarboxylic acid, a photopolymerization initiator, a diluent, and a ring Oxygen resin (see Patent Document 1). Based on this curable resin composition, excellent developability and resolution can be obtained, and by thermosetting after pattern formation, a three-dimensional A cured film with excellent adhesion, hardness, heat resistance, electroless gold plating resistance, electrical insulation, etc. of the mesh structure.

On the other hand, in the manufacturing process of printed wiring boards, after forming a cured film such as a solder resist layer, plating is usually applied to connection terminals such as conductor pads as a pre-treatment for surface protection of conductors and bonding.

As this kind of plating, electroless gold plating is used because it does not require energization or plating bars. tinned. This electroless tin plating is displacement plating. Since tin is deposited while dissolving the copper surface of the conductor layer, as described in Patent Document 1, it is applied on the solder resist layer made of curable resin composition, etc. In the patterned opening of the permanent coating, the solution of electroless tin plating penetrates from the interface between the solder resist layer and copper, causing the solder resist layer to peel off.

In this regard, the development of a curable resin composition with excellent electroless tin plating resistance was sought, but it was found that if an attempt was made to improve the electroless tin plating resistance, the dry-to-touch property (non-tackiness) of the dry coating surface deteriorated, and in When it is exposed to a negative film by contacting it, there is a new problem that contact marks of the negative film are produced on the surface of the dried film.

[Patent Document 1] Japanese Patent Publication No. 1-54390

[Problem to be solved by the invention]

Here, the purpose of the present invention is to provide an electroless tin plating resistance after hardening, which can maintain the original characteristics such as excellent developability and resolution, and does not cause problems such as deterioration of dryness to the touch (no tackiness). It is a curable resin composition for the pattern of the cured film that is excellent in adhesion to various substrates, soldering heat resistance, moisture resistance, chemical resistance, electrical insulation and other properties. [Means to solve the problem]

As a result of careful research by the present inventors in order to achieve the above object, it has been found that polyester having both an aromatic structure and a polyether structure does not reduce the developability and heat resistance of the curable resin composition, but improves the compatibility with the undercoat layer (undercoat). ) of the copper adhesion, and then complete the present invention.

That is, the curable resin composition of the present invention is characterized in that it contains: (A) carboxyl group-containing resin, (B) photopolymerization initiator, (C) thermosetting compound, (D) photopolymerizable monomer, and (E) a polyester having both an aromatic structure and a polyether structure. In the curable resin composition of the present invention, the aforementioned (E) polyester having both an aromatic structure and a polyether structure is preferably a polyester obtained by reacting an alkylene oxide adduct of bisphenol with a polycarboxylic acid . It is considered that the thermal stability is improved by the aromatic structure of bisphenol, etc., and the flexibility is imparted by the introduced polyether structure by making it an alkylene oxide adduct, and by making it react with a polycarboxylic acid The obtained polyester can be adjusted to the most appropriate solubility as a composition to improve soldering heat resistance and electroless tin plating resistance. The dry film of the present invention is characterized by applying the aforementioned curable resin composition to a film and drying it. The cured product of the present invention is characterized in that it is obtained by subjecting the aforementioned curable resin composition or the curable resin composition constituting the aforementioned dry film to at least one of photocuring and thermosetting. The printed wiring board of this invention is characterized by having the said hardened|cured material. [Effect of the invention]

According to the present invention, it is possible to provide a curable resin composition that maintains resolution, has no tackiness after drying, and has improved electroless tin plating resistance and soldering heat resistance compared to the prior art.

The curable resin composition of the present invention will be specifically described below, but the present invention is not limited thereto.

In addition, when there are isomers of the described compounds, all possible isomers can be used in the present invention unless specifically excluded.

<Composition of Curable Resin Composition> The curable resin composition of the present invention is characterized by containing: (A) carboxyl group-containing resin, (B) photopolymerization initiator, (C) thermosetting compound, (D) photopolymerizable monomer, (E) Polyester with both aromatic structure and polyether structure. In addition, the curable resin composition of the present invention may contain other optional components such as inorganic fillers within the range that does not inhibit the effects of the present invention.

[(A) Resin containing carboxyl group] As the carboxyl group-containing resin, known ones can be used as long as they have a carboxyl group in the molecule. Moreover, carboxyl group-containing resin may be used individually by 1 type, and may use it in combination of 2 or more types.

The carboxyl group-containing resin is preferably a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond in the molecule from the viewpoint of photocurability and development resistance. The ethylenically unsaturated double bond is preferably derived from acrylic acid or methacrylic acid or derivatives thereof. By using a carboxyl group-containing resin having an ethylenically unsaturated double bond, it is easy to make the composition photocurable.

Specific examples of the carboxyl group-containing resin include the following compounds (either an oligomer or a polymer may be used).

(I) Copolymerization of unsaturated carboxylic acids such as (meth)acrylic acid with compounds containing unsaturated groups such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, isobutylene, etc. Carboxyl resin.

(II) Diisocyanates such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate, and diols containing carboxyl groups such as dimethylol propionic acid and dimethylol butyric acid Compounds and polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, phenolic hydroxyl groups and Carboxyl group-containing urethane resin obtained by polyaddition reaction of diol compounds such as alcoholic hydroxyl compounds.

(III) By diisocyanate, with bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol (bixylenol) type (meth)acrylate of bifunctional epoxy resin such as epoxy resin and biphenol type epoxy resin or its partial anhydride modification, diol compound containing carboxyl group and polyaddition reaction of diol compound containing carboxyl group Photosensitive urethane resin.

(IV) In the synthesis of the resin of (II) or (III) above, a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, is added , Carboxyl-containing photosensitive urethane resin obtained by terminal (meth)acrylation.

(V) In the synthesis of the above-mentioned (II) or (III) resin, add the equimolar reaction products of isophorone diisocyanate and pentaerythritol triacrylate, etc., which have one isocyanate group and more than one (methanol) in the molecule. A carboxyl group-containing photosensitive urethane resin obtained by terminal (meth)acrylation of acryl group compounds.

(VI) A carboxyl-containing photosensitive resin obtained by reacting a bifunctional or more polyfunctional (solid) epoxy resin with (meth)acrylic acid, and adding a dibasic anhydride to a hydroxyl group existing on the side chain.

(VII) The hydroxyl group of the bifunctional (solid) epoxy resin is further epoxidized with epichlorohydrin (epichlorohydrin) and the polyfunctional epoxy resin is reacted with (meth)acrylic acid, and the dibasic acid anhydride is added to the generated hydroxyl group The obtained photosensitive resin containing carboxyl groups.

(VIII) React difunctional oxetane resin with dicarboxylic acids such as adipic acid, phthalic acid, and hexahydrophthalic acid, and add phthalic anhydride, Carboxyl-containing polyester resin obtained from dibasic anhydrides such as tetrahydrophthalic anhydride and hexahydrophthalic anhydride.

(IX) An epoxy compound having a plurality of epoxy groups in one molecule, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule such as p-hydroxyphenethyl alcohol, and (meth)acrylic acid react with monocarboxylic acids containing unsaturated groups, and react the alcoholic hydroxyl groups of the resulting reaction products with polyhydric anhydrides such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and adipic acid. Resins containing carboxyl groups obtained by the reaction of acid anhydrides.

(X) The reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide is reacted with a monocarboxylic acid containing an unsaturated group, and the resulting A carboxyl group-containing photosensitive resin obtained by reacting the reaction product with polybasic acid anhydride.

(XI) The reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacts with a monocarboxylic acid containing an unsaturated group , A carboxyl-containing photosensitive resin obtained by reacting the obtained reaction product with a polybasic anhydride.

(XII) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth)acryl groups in one molecule to the above-mentioned resins (I) to (XI) .

The acid value of the carboxyl-containing resin is suitably in the range of 30-150 mgKOH/g, more preferably in the range of 50-120 mgKOH/g. Alkali image development becomes easy by making the acid value of resin containing a carboxyl group 30 mgKOH/g or more. Moreover, by setting it as 150 mgKOH/g or less, it becomes easy to draw a normal resist pattern by dissolving and peeling an unexposed part, preventing the dissolution of the exposed part by a developing solution.

The weight average molecular weight of the carboxyl group-containing resin (hereinafter sometimes abbreviated as Mw) varies depending on the resin skeleton, but generally, it is preferably in the range of 2,000 to 150,000, and more preferably in the range of 3,000 to 100,000. When the weight average molecular weight is 2,000 or more, the moisture resistance of the resin layer after exposure becomes favorable, film loss at the time of image development hardly occurs, and resolution becomes favorable. Moreover, image development resistance and storage stability will become favorable as a weight average molecular weight is 150,000 or less. The weight average molecular weight can be determined by gel permeation chromatography.

Carboxyl group-containing resins can be used without being limited to those listed above. Among them, using a phenolic compound such as the aforementioned carboxyl group-containing resins (X) and (XI) as a starting material, the HAST resistance (highly accelerated life test) and PCT resistance (saturated steam pressure test) of the synthesized carboxyl group-containing resin ) is excellent, so it can be preferably used.

The blending amount of the carboxyl group-containing resin is based on the total amount of the resin composition, preferably 5-60% by mass, more preferably 10-60% by mass, further preferably 15-60% by mass, and most preferably 20-50% by mass %. If it falls within this range, the strength of the coating film will be good, the viscosity of the composition will be moderate, and the applicability and the like can be improved.

[(B) Photopolymerization initiator] A well-known one can be used as a photoinitiator. Moreover, a photoinitiator may be used individually by 1 type, and may use it in combination of 2 or more types.

Examples of photopolymerization initiators include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethyl Phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide , bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl Phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)- Bisacylphosphine oxides such as phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4, Methyl 6-trimethylbenzoylphenylphosphinate, 2-methylbenzoyldiphenylphosphine oxide, isopropyl trimethylacetylphenylphosphinate, 2,4, Monoacyl phosphine oxides such as 6-trimethylbenzoyldiphenylphosphine oxide; ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, 1-hydroxy-cyclo Hexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[ 4-(2-Hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropane- 1-ketone and other hydroxyacetophenones; benzoin (benzoin), diphenyl ketone (benzil) and other benzoins; benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether Benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorodiphenyl Benzophenone, 4,4'-bisdiethylaminodiphenyl ketone and other diphenyl ketones; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2 ,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio) Phenyl]-2-morpholinyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1,2-(dimethyl Amino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminobenzene Acetophenones such as ethyl ketone; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone , 2-chlorothioxanthone, 2,4-diisopropylthioxanthone and other thioxanthones; anthraquinone, chloranthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert- Anthraquinones such as butyl anthraquinone, 1-chloroanthraquinone, 2-pentyl anthraquinone, 2-aminoanthraquinone, etc.; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal (ketal ) class; benzoic acid esters such as ethyl 4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and ethyl p-dimethylbenzoate; 1,2-octanedi Ketone (octadione), 1-[4-(phenylthio)-, 2-(O-benzoyl oxime)], ethyl ketone, 1-[9-ethyl-6-(2-methylbenzyl Acyl)-9H-carbazol-3-yl]-,1-(O-acetyl oxime) and other oxime esters; bis(η5-2,4-cyclopentadien-1-yl)-bis( 2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrole -1-yl)ethyl)phenyl]titanium and other titanocenes; phenyl disulfide 2-nitrostilbene, butyroin, anisoin diethyl ether, azobisisobutyl Nitrile, tetramethylamine thioformyl disulfide, etc.

The content of the photopolymerization initiator is preferably 0.1 to 30 parts by mass in terms of non-volatile components relative to 100 parts by mass of the carboxyl group-containing resin. When it is 0.1 mass part or more, the photocurability of a resin composition becomes favorable, a coating film is hard to peel off, and coating film characteristics, such as chemical resistance, also become favorable. Moreover, when it is 30 mass parts or less, the effect of reducing outgassing (outgas) can be acquired, and also the light transmittance of a coating will become favorable, and deep part hardening property will hardly fall. More preferably, it is 0.5-20 mass parts.

[(C) thermosetting compound] As a thermosetting compound, a well-known thing can be used. Moreover, a thermosetting compound can be used individually by 1 type or in combination of 2 or more types.

Examples of thermosetting compounds include melamine resins, benzoguanamine resins, amino resins such as melamine derivatives and benzoguanamine derivatives, isocyanate compounds, blocked isocyanate compounds, cyclocarbonate compounds, epoxy resins, etc. Compounds, oxetane compounds, episulfide resins, bismaleimide, carbodiimide resins, etc.

As the epoxy compound, epoxidized vegetable oil; bisphenol A type epoxy resin; hydroquinone type epoxy resin; bisphenol type epoxy resin; thioether type epoxy resin; brominated epoxy resin; Oxygen resin; cresol novolac epoxy resin; biphenol novolak epoxy resin; bisphenol F epoxy resin; hydrogenated bisphenol A epoxy resin; glycidylamine epoxy resin; hydantoin Cycloaliphatic epoxy resins; epoxy resins of trihydroxyphenylmethane type; epoxy resins of bixylenol type or biphenol type or mixtures thereof; epoxy resins of bisphenol S type; bisphenol A Novolak type epoxy resin; Tetrahydroxyphenylethane type epoxy resin; Heterocyclic epoxy resin; Diglycidyl phthalate resin; Tetraglycidyl xylyl ethane Resin; epoxy resin containing naphthyl; epoxy resin with dicyclopentadiene skeleton; glycidyl methacrylate copolymerized epoxy resin; cyclohexylmaleimide and glycidyl methacrylate Copolymerized epoxy resin; epoxy modified polybutadiene rubber derivatives; CTBN modified epoxy resin, etc., but not limited to these. These epoxy resins can be used individually by 1 type or in combination of 2 or more types.

Examples of oxetane compounds include bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methoxy base] ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy) ) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3-oxetanyl) methyl acrylate, (3-methyl methacrylic acid - 3-oxetanyl) methyl ester, (3-ethyl-3-oxetanyl) methyl methacrylate or polyfunctional oxetanes such as oligomers or copolymers thereof In addition, oxetane alcohol and novolak resin, poly(p-hydroxystyrene), cardo (cardo) type bisphenols, calixarene, resorcinol calixarene (calixresorcinarene) Or ether compounds with hydroxyl-containing resins such as silsesquioxane, etc. In addition, a copolymer of an unsaturated monomer having an oxetane and an alkyl (meth)acrylate, etc. are also exemplified.

Examples of the episulfide resin include bisphenol A type episulfide resin and the like. In addition, using the same synthesis method, an episulfide resin in which the oxygen atom of the epoxy group of the novolak-type epoxy resin is replaced with a sulfur atom can also be used.

Examples of amino resins such as melamine derivatives and benzoguanamine derivatives include methylol melamine compounds, methylol benzoguanamine compounds, methylol acetylene urea compounds, and methylol urea compounds.

A polyisocyanate compound can be blended as an isocyanate compound. Examples of polyisocyanate compounds include 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, naphthalene-1,5-diisocyanate, o-xylene diisocyanate, Aromatic polyisocyanates such as m-xylene diisocyanate and 2,4-toluene dimer; tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate , 4,4-methylene bis(cyclohexyl isocyanate) and aliphatic polyisocyanate such as isophorone diisocyanate; alicyclic polyisocyanate such as biscycloheptane triisocyanate; and adducts of the previously listed isocyanate compounds, Biuret body and isocyanurate (isocyanurate) body, etc.

As the blocked isocyanate compound, an addition reaction product of an isocyanate compound and an isocyanate blocking agent can be used. As an isocyanate compound obtained by reacting with an isocyanate blocking agent, the said polyisocyanate compound etc. are mentioned, for example. Examples of isocyanate blocking agents include phenol-based blocking agents; lactamide-based blocking agents; active methylene-based blocking agents; alcohol-based blocking agents; oxime-based blocking agents; thiol-based blocking agents; Amine (acid amide)-based blocking agent; imide-based blocking agent; amine-based blocking agent; imidazole-based blocking agent; imine-based blocking agent, etc.

The content of the thermosetting compound is preferably 0.2-2.0 mol, more preferably 0.5-1.5 mol of functional groups of the thermosetting compound to be reacted per 1 mol of carboxyl groups contained in the carboxyl-containing resin.

[(D) Photopolymerizable monomer] A compound having an ethylenically unsaturated double bond in a photopolymerizable monomer system can be polymerized by addition reaction between ethylenically unsaturated double bonds, for example, by light irradiation. By using a photopolymerizable monomer, the tolerance to the developing solution in the exposed part and the solubility to the developing solution in the unexposed part become large, and the resolution improves.

Examples of such photopolymerizable monomers include alkyl (meth)acrylates such as 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate; Hydroxyalkyl (meth)acrylates such as esters, 2-hydroxypropyl (meth)acrylate, etc.; mono or di(methyl)alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, etc. Acrylic esters; polyols such as hexanediol, trimethylolpropane, pentaerythritol, di-trimethylolpropane, dipentaerythritol, trishydroxyethyl isocyanurate, or their ethylene oxide or epoxy Poly(meth)acrylates of propane adducts; (meth)acrylates of propane adducts; (meth)acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate, etc. ; and melamine (meth)acrylate; etc.

A photopolymerizable monomer can be used individually by 1 type or in combination of 2 or more types. The content of the photopolymerizable monomer is preferably 5 to 40 parts by mass in terms of non-volatile components relative to 100 parts by mass of the carboxyl group-containing resin. When the content of the photopolymerizable monomer is within this range, the photocurability by exposure can be improved, and the pattern accuracy can be improved in the developing step after exposure. Moreover, when it is 40 mass parts or less, halation is hard to generate|occur|produce, and favorable resolution is obtained.

[(E) Polyester with both aromatic structure and polyether structure] The polyester having both an aromatic structure and a polyether structure is a polycondensate of a polycarboxylic acid and a polyhydric alcohol having an aromatic structure and a polyether structure, and known ones can be used. Moreover, this polyester may be used individually by 1 type, and may use it in combination of 2 or more types.

As the polyvalent carboxylic acid, known ones can be used, and one type may be used alone, or two or more types may be used in combination. Moreover, the polyhydric carboxylic acid of this invention may contain the anhydrate.

Examples of polycarboxylic acids include malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, phthalic anhydride, hexahydrophthalic acid, Formic anhydride, tetrahydrophthalic anhydride, isophthalic acid, terephthalic acid, nadic anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, pimelic acid, octane The diacid, dodecanedioic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic anhydride can be appropriately selected from the solubility of the polyester in the composition.

As long as the polyol includes polyols having an aromatic structure and a polyether structure, known ones can be used, and one type may be used alone or two or more types may be used in combination.

Examples of polyols with aromatic structure and polyether structure include 1,4-benzenedimethanol, 1,3-benzenedimethanol, 1,2-benzenedimethanol, 4,4'-naphthalene dimethanol, 3,4' -Aromatic polyols such as naphthalene dimethanol; 1,2,3-trihydroxybenzene, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4'-dihydroxydiphenylmethane Ketone, dihydroxyacetophenone, 1,1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane (also known as bisphenol F), 2,2-bis(4-hydroxyphenyl) Phenyl)propane (also known as bisphenol A), bis(4-hydroxyphenyl)sulfone (also known as bisphenol S), bis(4-hydroxyphenyl)ether, 4,4'-biphenol, 1 ,1-bis(4-hydroxyphenyl)isobutane, 2,2-bis(4-hydroxy-tert-butylphenyl)propane, 2-methyl-1,1-bis(4-hydroxyphenyl) ) propane, catechol, resorcinol, hydroquinone, novolak, resol, 1,1,1-(4-hydroxyphenyl)ethane and other polyphenols; bis-( Naphthalene polyols such as 2-hydroxynaphthyl)methane, 1,5-dihydroxy-naphthalene, and other dihydroxynaphthalene; etc., and derivatives of alkylene oxide added to them.

Among them, the polyol is preferably a polyol obtained by adding a flexible alkylene oxide to bisphenols such as 1,1-bis(4-hydroxyphenyl)ethane having excellent thermal stability, especially, more preferably A polyol obtained by adding alkylene oxide to 2,2-bis(4-hydroxyphenyl)propane (“bisphenol A”).

Also, since the polyol exhibits electroless tin plating resistance and soldering heat resistance in a good balance, it is preferably a polyol obtained by adding 2 to 30 moles of alkylene oxide to bisphenols, and more preferably 4 ~20 moles of alkylene oxide to obtain polyols. By adding more than 2 moles of alkylene oxide, the flexibility or the adhesion to the copper of the undercoat layer is excellent, and sufficient resistance to electroless tin plating can be obtained. By less than 30 moles, it is possible to obtain Curable resin composition with excellent soldering heat resistance, dry-to-touch property, and surface hardness.

Furthermore, the alkylene oxide is preferably ethylene oxide, propylene oxide, or butylene oxide.

As a method of adding an alkylene oxide to bisphenols, the method of adding an alkylene oxide and making it react by a well-known usual method using bisphenols as an initiator is mentioned, for example. Moreover, at the time of reaction, a well-known esterification catalyst can be used.

As an esterification catalyst, organic titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate, tin octoate, dibutyltin oxide, dibutyltin laurate, stannous chloride, bromine Tin-based compounds such as stannous oxide, etc.

The content of the polyester having both an aromatic structure and a polyether structure is preferably 1 to 50 parts by mass in terms of non-volatile components relative to 100 parts by mass of the carboxyl group-containing resin. When the content of the polyester having both an aromatic structure and a polyether structure is within this range, a curable resin composition having excellent electroless tin plating resistance or soldering heat resistance without deteriorating resolution can be obtained.

The number average molecular weight (hereinafter sometimes abbreviated as Mn) of the polyester having both an aromatic structure and a polyether structure is preferably in the range of 3,000 to 15,000, more preferably in the range of 5,000 to 10,000. In addition, the number average molecular weight can be measured by gel permeation chromatography.

The hydroxyl value of the polyester having both an aromatic structure and a polyether structure is preferably 0.2-100, more preferably 0.5-80. If the Mn and hydroxyl value of the polyester are within this range, the development resistance of the exposed area and the development property of the unexposed area can be improved, and excellent resolution can be obtained, and even as a hardened product, soldering heat resistance or surface Curable resin composition with excellent hardness.

[other ingredients] Other components include well-known additives generally used in curable resin compositions, such as inorganic fillers, organic fillers, colorants, organic solvents, thermosetting catalysts, photoinitiating aids, cyanate compounds, Elastomers, mercapto compounds, urethanization catalysts, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper damage inhibitors, antioxidants, rust inhibitors, fine powders Viscosifiers such as silicon dioxide, organic bentonite, and montmorillonite, defoamers and/or leveling agents such as silicone, fluorine, and polymer systems, imidazoles, thiazoles, and triazoles Flame retardants such as silane coupling agents, phosphinates, phosphate derivatives, phosphazene compounds and other phosphorus compounds, etc.

As the inorganic filler, known ones can be used, and one type may be used alone, or two or more types may be used in combination.

Specific examples of inorganic fillers include titanium oxide, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, fly ash, silica (natural silica or synthetic silica), kaolin, calcium oxide, Magnesium oxide, zinc oxide, barium sulfate, aluminum oxide, talc, mica, hydrotalcite, diaspore, calcium hydroxide, wollastonite, potassium titanate, barium titanate, magnesium sulfate, calcium sulfate, sepiolite, copper , iron, carbon black, alumina, zirconia, antimony oxide, lead white, zinc hydroxide, zinc sulfide, lead titanate, aluminum nitride, silicon nitride, titanium nitride, diamond powder, zirconium silicate, mica powder , lead sulfate, cerium fluoride, cerium oxide, aluminum phosphinate, aluminum silicate, magnesium silicate, calcium silicate, clay, calcined talc, magnesium phosphate, gold vermiculite, boron nitride, aluminum borate, silicon Silica balloon, glass flake, glass balloon, amorphous silica, crystalline silica, fused silica, spherical silica, ironmaking slag, iron oxide, iron Silicon aluminum (sendus), alnico magnet, various ferrite and other magnetic powder, cement, glass powder, dewatered sludge, Neuburg silica, diatomaceous earth, antimony trioxide, magnesium oxysulfide, aluminum hydrate, hydrated Phosphorous metal salts such as gypsum, alum, aluminum phosphinate, etc.

The inorganic filler is preferably silica, barium sulfate, or talc from the viewpoint of coatability, adhesion, and chemical resistance, and more preferably silica from the viewpoint of thermal dimensional stability.

The average particle size of the inorganic filler is not particularly limited, as long as it is a particle size that can be used as the inorganic filler. The average particle size is the average particle size obtained from the volume-averaged particle size distribution measurement results measured by a laser diffraction particle size distribution measuring device, and is preferably 0.1 μm to 30 μm, more preferably 0.1 μm to 10 μm.

The blending amount of the inorganic filler is preferably 5 to 350 parts by mass, more preferably 10 to 300 parts by mass, and still more preferably 30 to 250 parts by mass in terms of non-volatile components relative to 100 parts by mass of the carboxyl group-containing resin range of servings. By setting it as this range, the hardened|cured material which has excellent heat resistance and physical strength can be obtained.

Well-known ones can be used as an organic solvent. Moreover, an organic solvent may be used individually by 1 type, and may use it in combination of 2 or more types.

Specific examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; Basecellosu, Carbitol, Methyl Carbitol, Butyl Carbitol, Propylene Glycol Monomethyl Ether, Dipropylene Glycol Monomethyl Ether, Dipropylene Glycol Diethyl Ether, Diethylene Glycol Monomethyl Ether Acetate, Tripropylene Glycol Glycol ethers such as monomethyl ether; Ester, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, propylene carbonate and other esters; octane, decane and other aliphatic hydrocarbons; petroleum ether, naphtha, mineral spirits and other petroleum solvents ;wait.

Organic solvents are generally used for the preparation of compositions, the formation of dry films, and the adjustment of viscosity when coating on printed wiring boards. Therefore, the content of the organic solvent can be appropriately changed according to the purpose.

＜How to use curable resin composition＞ Next, a method of forming a dry film as an example of a method of using the curable resin composition of the present invention, and a method of forming a cured product of the curable resin composition on a printed wiring board will be described.

[Formation method of dry film] A dry film is generally obtained by performing a coating step and a drying step. The following describes each step.

(coating step) The viscosity of the curable resin composition is adjusted with an organic solvent as necessary, and coated on a support film (hereinafter, also referred to as "carrier film") with a desired thickness.

As the support film, polyester films such as polyethylene terephthalate, polyimide films, polyamideimide films, polypropylene films, polystyrene films and other plastic films are preferably used.

The thickness of the support film may be, for example, in the range of 10 to 150 μm.

As the coating method, for example, a notch wheel coater, a knife coater, a lip coater (lip coater), a bar coater, an extrusion coater, a reverse coater, a transfer roll coater, a gravure coater, a spray coating machine etc.

The coating film thickness can be appropriately set, for example, in the range of 3 to 100 μm, preferably 5 to 40 μm, in terms of the film thickness after drying.

(drying step) The organic solvent contained in the curable resin composition coated on the support film is volatilized and dried to form a resin layer (dried coating film).

As a drying means, a hot-air circulation type drying oven, an IR oven, a hot plate, a convection oven, etc. are mentioned, for example.

The drying conditions can be, for example, a drying temperature of 50 to 130° C., a drying time of 1 to 30 minutes, and the like.

For the purpose of preventing dust adhesion, a peelable protective film (hereinafter also referred to as "cover film") may be laminated on the surface of the resin layer formed on the support film.

As the protective film, when the protective film is peeled off, the adhesive force between the resin layer and the protective film may be smaller than the adhesive force between the resin layer and the support film. As a protective film, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. can be used, for example.

[How to form hardened product] Generally, the cured product is obtained by performing a resin layer forming step, an exposure step, a development step, and a thermal curing step. The following describes each step.

(Resin layer forming step) If necessary, the viscosity of the curable resin composition is adjusted with an organic solvent, and it is applied to a substrate such as a printed wiring board with a desired thickness. Next, the organic solvent contained in the curable resin composition applied on the substrate is evaporated and dried to form a resin layer on the substrate.

Examples of coating methods include screen printing, curtain coating, spray coating, and roll coating.

The coating film thickness can be appropriately set, for example, in the range of 3 to 100 μm, preferably 5 to 40 μm, in terms of the film thickness after drying.

As a drying means, a hot-air circulation type drying oven, an IR oven, a hot plate, a convection oven, etc. are mentioned, for example.

The drying conditions can be, for example, a drying temperature of 50 to 130° C., a drying time of 1 to 30 minutes, and the like.

The method of forming the resin layer on a base material such as a printed wiring board may be a method of laminating the above-mentioned dry film on the printed wiring board, and transferring the resin layer provided on the dry film to the printed wiring board.

(exposure step) The resin layer is irradiated with active energy rays through a photomask formed with a specific exposure pattern to selectively expose the resin layer.

Examples of light sources for irradiating active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, xenon lamps, and metal halide lamps.

Here, the exposure method can be classified into a contact exposure method in which a mask is in contact with a resin layer, and a non-contact exposure method in which a mask is not in contact with a resin layer.

The contact exposure method has high resolution because the photomask is in contact with the resin layer. On the other hand, when the photomask is removed after exposure, the resin layer adheres to the photomask to contaminate the photomask, and the automatic exposure machine stops abnormally. A situation where productivity deteriorates. In the non-contact exposure method, since the distance between the photomask and the resin layer is long, while the continuous productivity is high, the resolution tends to be low.

The resin layer obtained using the curable resin composition of the present invention can be used in any of the above-mentioned non-contact exposure method and contact exposure method. The curable resin composition of the present invention can be suitably used in a contact exposure method because of its excellent dryness to touch.

(developing step) After the exposure step, the unexposed portion of the resin layer is removed to form a pattern by developing with an aqueous alkali solution.

Examples of the aqueous alkali solution include aqueous alkali solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines.

(Thermohardening step) After the development step, the patterned resin layer is formed and further cured by heating (for example, 100~220°C) after being irradiated with active energy rays, or irradiated with active energy rays after being cured by heating, or finalized only by curing by heating Hardening (official hardening) to form a hardened product with a specific pattern on a substrate such as a printed wiring board.

The printed wiring board having the cured product of the curable resin composition of the present invention thus obtained can be used in various applications, but it is particularly suitable for automotive use because it employs electroless tin plating and has excellent heat resistance. [Example]

The present invention will be specifically described below by showing examples and comparative examples, but the present invention is not limited by the following examples. In addition, the following "parts" are all mass standards unless otherwise specifically excluded.

[raw material] Resin A containing carboxyl groups and polyesters E-1~E-3 having both aromatic structure and polyether structure were prepared by the method described below, and commercially available products were used for others. (A) Resin containing carboxyl group: Resin A containing carboxyl group (non-volatile content 65% by mass, solid content acid value 85 mgKOH/g, weight average molecular weight about 3,500) (B-1) Photopolymerization initiator: Irgacure907 (manufactured by BASF Corporation) (B-2) Photopolymerization initiator: Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd.) (C) Thermosetting compound: N-695 (cresol novolak type epoxy manufactured by DIC Corporation) (D) Photopolymerizable monomer: dipentaerythritol hexaacrylate (DPHA) (E-1) Polyester with both aromatic structure and polyether structure: Polyester E-1 Number average molecular weight Mn: 3,000 (E-2) Polyester with both aromatic structure and polyether structure: Polyester E-2 Number average molecular weight Mn: 8,000 (E-3) Polyester with both aromatic structure and polyether structure: Polyester E-3 Number average molecular weight Mn: 15,000 Inorganic filler (silicon dioxide): Adamafine SO-E2 (manufactured by Admatechs) Coloring agent: Phthalo blue Colorant: Chromophthal Yellow Hardening catalyst 1: dicyandiamide (DICY) Hardening catalyst 2: Melamine Defoamer: KS-66 (manufactured by Shin-Etsu Silicone Co., Ltd.)

(Preparation of resin containing carboxyl group) Synthesis example <Carboxyl group-containing resin A> Add 220 parts by mass of cresol novolak type epoxy resin (manufactured by DIC Corporation, registered trademark "EPICLON" N-695, epoxy equivalent: 220) into a four-necked flask equipped with a stirrer and a reflux cooler, and then add carbitol 214 parts by mass of acetate were heated and dissolved. Next, 0.1 parts by mass of hydroquinone as a polymerization inhibitor and 2.0 parts by mass of dimethylbenzylamine as a reaction catalyst were added. This mixture was heated at 95-105 degreeC, and 72 parts of acrylic acid were dripped slowly, and it was made to react for 16 hours. The reaction product was cooled to 80 to 90° C., 106 parts by mass of tetrahydrophthalic anhydride was added and reacted for 8 hours, and it was taken out after cooling. The thus obtained photosensitive resin having both ethylenically unsaturated bonds and carboxyl groups had a non-volatile content of 65% by mass, an acid value of solid matter of 85 mgKOH/g, and a weight average molecular weight Mw of about 3,500. In addition, the weight average molecular weight of the obtained resin was obtained by connecting the pump LC-6AD manufactured by Shimadzu Corporation with three columns Shodex (registered trademark) KF-804, KF-803, Determination by KF-802 high performance liquid chromatography.

(Preparation of polyester with both aromatic structure and polyether structure) Synthesis Example 1 <Polyester E-1 (number average molecular weight: 3,000)> In a 2-liter four-necked flask, add 800 parts by mass of ethylene oxide 6 mole adducts of bisphenol A, 180 parts by mass of adipic acid, and titanium tetraisopropoxide (titanium tetraisopropoxide) as an esterification catalyst. tetraisopropoxide) was reacted at 220° C. to synthesize polyester E-1.

Synthesis Example 2 <Polyester E-2 (number average molecular weight: 8,000)> In a 2-liter four-neck flask, add 800 parts by mass of ethylene oxide 6 molar adduct of bisphenol A, 200 parts by mass of adipic acid, and 0.2 parts by mass of titanium tetraisopropoxide as an esterification catalyst Parts were reacted at 220°C to synthesize polyester E-2.

Synthesis Example 3 <Polyester E-3 (number average molecular weight: 15,000)> In a 2-liter four-neck flask, add 800 parts by mass of ethylene oxide 6 molar adduct of bisphenol A, 220 parts by mass of adipic acid, and 0.2 parts by mass of titanium tetraisopropoxide as an esterification catalyst Parts were reacted at 220°C to synthesize polyester E-3.

(Preparation of Curable Resin Composition) With the composition (parts by mass) shown in Table 1, each component was premixed with a mixer, and then kneaded with a three-roll mill to prepare a curable resin composition.

(Preparation of test substrates) (1) The curable resin composition prepared in each of the examples and comparative examples was coated on the entire surface using a 100-mesh polyester mesh by screen printing to a thickness of 20 to 30 μm. On printed wiring boards on which circuits are formed. Next, the coating film was dried for 30 minutes using a hot-air circulation drying oven at 80° C. to prepare a test substrate for a finger-drying test. (2) Next, on the above-mentioned test substrate, a photomask having a line pattern of 30 to 150 μm (10 μm scale) was adhered to the dry coating film, and an ultraviolet exposure device (manufactured by Oak Manufacturing Co., Ltd., model HMW-680GW) was irradiated with ultraviolet rays (exposure amount: 300 mJ/cm ² ), followed by developing for 60 seconds at a spray pressure of 0.2 MPa using 1 mass % sodium carbonate aqueous solution. After that, heat and harden in a hot air circulation drying oven at 150°C for 60 minutes, let it cool to room temperature, and then irradiate it with a high-pressure mercury lamp at 1000 mJ/cm ² to make it for resolution, soldering heat resistance, and electrolysis. Test substrate for tin plating resistance test.

Using the test substrates produced in this way, dry-to-touch properties, image resolution, soldering heat resistance, and electroless tin plating resistance were evaluated. The test method and evaluation method of these evaluations are as follows. The evaluation results are shown in Table 1 together. (1) Dryness to touch: With respect to the above-mentioned test substrate, the dryness to touch of the coated film surface after direct contact with a finger was evaluated according to the following criteria. ◎: No stickiness at all. ○: Slightly sticky. ×: There is stickiness.

(2) Resolution: The line pattern of the said test board|substrate was measured with the optical microscope, and it evaluated by the following reference|standard. ⊚: The remaining line width is less than 50 μm. ○: The remaining line width is less than 100 μm. ×: The remaining line width is 100 μm or more.

(3) Soldering heat resistance: After coating the rosin-based flux on the test substrate, it was dipped in a solder bath set at 260°C for 30 seconds. After washing this test board|substrate with an organic solvent, the peeling test was performed with the cellophane adhesive tape, and it evaluated by the following reference|standard. ◎: No change in appearance. ◯: Slight peeling was confirmed in the cured coating film. Δ: Peeling was confirmed in the cured coating film. X: Those whose cured coating film floating and solder penetration were confirmed before the peeling test.

(4) Resistance to electroless tin plating: According to the procedure described later, electroless tin plating was performed on the test substrate, and the change in appearance and the peeling test using cellophane adhesive tape were performed on the test substrate, and the peeling state of the cured film was evaluated according to the following criteria. ◎: There is no change in the appearance, and there is no peeling off of the hardened film. ◯: Although there is no change in appearance, the cured film peels off slightly. ×: Swelling of the cured film and infiltration of the plating were confirmed, and the peeling of the cured film was large in the peeling test.

Electroless tin plating steps: 1. Degreasing: Immerse the test substrate in an acidic degreasing solution (manufactured by Japan MacDermid Co., Ltd., a 20 vol% aqueous solution of MetexL-5B) at 30°C for 3 minutes. 2. Water washing: immerse the test substrate in running water for 3 minutes. 3. Soft etching: Immerse the test substrate in 14.3 mass % ammonium persulfate aqueous solution for 1 minute at room temperature. 4. Water washing: immerse the test substrate in running water for 3 minutes. 5. Acid immersion: Immerse the test substrate in 10% by volume sulfuric acid aqueous solution for 1 minute at room temperature. 6. Water washing: immerse the test substrate in running water for 30 seconds to 1 minute. 7. Electroless tin plating: immerse the test substrate in a tin plating solution at 70°C and pH=1 (Atotech shares are limited, Stannatech H plus 73 parts by volume, SF special acid 6 parts by volume, SF Tin Solution C 5.5 parts by volume, Stannatech SN correction solution 15.5 parts by volume, Stannatech additive C 0.125 parts by volume solution) for 12 minutes. 8. Water washing: immerse the test substrate in running water for 3 minutes.

From the evaluation results shown in the above table, it is clear that in each example, a curable resin composition having excellent soldering heat resistance and electroless tin plating resistance can be obtained while possessing dryness to touch and resolution property. things.

Claims (4)

A curable resin composition characterized by containing: (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a thermosetting compound, (D) a photopolymerizable monomer, and (E) Polyester with both aromatic structure and polyether structure; the aforementioned (E) polyester with both aromatic structure and polyether structure is a polyester obtained by reacting an alkylene oxide adduct of bisphenol with a polycarboxylic acid. ester. A dry film, which is obtained by applying the curable resin composition according to claim 1 to the film and drying it. A cured product characterized by being obtained by subjecting the curable resin composition according to claim 1 or the curable resin composition constituting the dry film according to claim 2 to at least one of photocuring and thermal curing . A printed wiring board characterized by having the hardened product as claimed in claim 3.