JP6704425B2 - Photosensitive resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photosensitive resin capable of obtaining a cured product having excellent flux cleaning liquid resistance.

A protective film (for example, an insulating film such as a solder resist) may be formed on a substrate (for example, a substrate on which a conductor circuit pattern is formed). A photocurable film of a photosensitive resin composition containing a photosensitive resin may be used as the protective film. In addition, a solder paste may be printed on a substrate on which a protective film is formed, and electronic components may be mounted in a reflow oven.

However, the solder paste contains a flux component in order to impart fluidity. In particular, when the solder paste is applied with a jet dispenser, more flux components are mixed in order to obtain the fluidity of the solder paste. Further, when the electronic component is mounted on the substrate in the reflow furnace, the non-aggregated metal (solder ball) may remain near the mounting portion. A flux cleaning liquid may be used to remove the solder balls and flux components remaining near the mounting portion.

As the flux cleaning liquid, for example, 75.0 to 99.2 mass% of the component (A) such as diethylene glycol monoalkyl ether, 0.5 to 10.0 mass% of the component (B) that is an alkanolamine, and 1 carbon atom A composition containing 0.3 to 5.0 mass% of the component (C) which is an alkylbenzenesulfonic acid having an alkyl group of 6 to 6 and/or a salt thereof (Patent Document 1).

Further, as a photosensitive resin composition for forming a protective film such as a solder resist on a substrate, for example, (A) one molecule has two or more unsaturated double bonds and one or more carboxyl groups. A photosensitive prepolymer, (B) photopolymerization initiator, (C) diluent, (D) epoxy compound, (E) polybutadiene having one or more internal epoxide groups in one molecule, and (F) polyurethane fine particles. The photosensitive resin composition containing it is mentioned (patent document 2).

On the other hand, when a flux cleaning liquid is used to remove the solder balls and flux components, the components of the flux cleaning liquid may soak into the protective film such as the solder resist, resulting in swelling or peeling of the protective film. .. When forming a protective film on a flexible printed wiring board, the protective film is required to have flexibility (flexibility). However, as a result of imparting flexibility to the protective film in terms of the resin skeleton contained in the photosensitive resin composition, there is a problem that the resistance to the flux cleaning liquid is particularly insufficient. Further, DI exposure (direct writing exposure) is frequently used from the viewpoint that fineness of cured film and high resolution are required. The cured coating film photocured by DI exposure has lower flux cleaning liquid resistance than the conventional cured coating film photocured by scattered light, and the cured coating film is more likely to swell or peel off. There was a problem that it would end up.

JP, 2009-298940, A JP-A-2002-293882

In view of the above circumstances, an object of the present invention is to provide a photosensitive resin composition capable of obtaining a cured product having excellent flux cleaning liquid resistance.

Aspects of the present invention include a photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound. The (A) carboxyl group-containing photosensitive resin contains 60 mass% or more of the carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton, and the (C) reactive diluent is a urethane bond. It is a photosensitive resin composition characterized by having no.

In the above aspect, 60% by mass or more of the carboxyl group-containing photosensitive resin having the cresol novolac type epoxy resin skeleton is contained in the (A) carboxyl group-containing photosensitive resin. Further, the constituent component of the reactive diluent (C) may be one kind or two or more kinds, but none of them has a urethane bond.

The aspect of this invention is a photosensitive resin composition characterized by further containing (E) organic filler.

An aspect of the present invention is the photosensitive resin composition, wherein the (E) organic filler is contained in an amount of 30 to 100 parts by mass based on 100 parts by mass of the (A) carboxyl group-containing photosensitive resin. ..

An aspect of the present invention is the photosensitive resin composition, wherein the (C) reactive diluent contains a (meth)acrylate compound having a functionality of 5 or more.

An aspect of the present invention is the photosensitive resin composition, wherein the (meth)acrylate compound having 5 or more functional groups is dipentaerythritol hexa(meth)acrylate and/or caprolactone-modified dipentaerythritol hexa(meth)acrylate.

In an aspect of the present invention, the (D) epoxy compound is at least two compounds selected from the group consisting of a biphenyl type epoxy compound, a dimer acid type epoxy compound, a phenol aralkyl type epoxy compound, and an epoxy compound having a triazine ring. It is a photosensitive resin composition characterized by containing.

According to the aspect of the present invention, (A) the carboxyl group-containing photosensitive resin contains 60% by mass or more of the carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton, and (C) the reactive diluent is a urethane bond. By not having the above, it is possible to obtain a cured product excellent in flux cleaning liquid resistance without impairing basic properties such as heat resistance.

According to the aspect of the present invention, by further containing (E) the organic filler, flexibility (flexibility) can be imparted to the cured product in addition to the flux cleaning liquid resistance. Therefore, it can be applied as a protective film for a flexible printed wiring board.

According to the aspect of the present invention, when the (C) reactive diluent contains a pentafunctional or higher functional (meth)acrylate compound, the heat resistance of the cured product can be reliably improved.

Next, the photosensitive resin of the present invention will be described in detail. The photosensitive resin group of the present invention is a photosensitive resin containing (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound. In the resin composition, the (A) carboxyl group-containing photosensitive resin contains 60 mass% or more of the carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton, and the (C) reactive diluent is , Has no urethane bond.

(A) Carboxyl group-containing photosensitive resin The carboxyl group-containing photosensitive resin contains 60% by mass or more of a carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton. The carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton is not particularly limited as long as it has a chemical structure having a cresol novolac type epoxy resin skeleton, and for example, a carboxyl group-containing photosensitive resin derived from a cresol novolac type epoxy resin. Examples of the resin include a resin. Specifically, for example, acrylic acid or methacrylic acid (hereinafter referred to as "(meth)acrylic acid") is present in at least a part of the epoxy groups of the cresol novolac type epoxy resin having two or more epoxy groups in one molecule. A) radical-polymerizable unsaturated monocarboxylic acid such as cresol novolac type epoxy (meth)acrylate to obtain a radical-polymerizable unsaturated monocarboxylic acid cresol novolac type epoxy resin, and the generated hydroxyl group is Examples thereof include polybasic acid-modified cresol novolac type epoxy (meth)acrylate and other polybasic acid-modified radically polymerizable unsaturated monocarboxylic cresol novolac type epoxy resins obtained by reacting a basic acid or an anhydride thereof.

The epoxy equivalent of the cresol novolac type epoxy resin is not particularly limited, but its upper limit value is preferably 2000 g/eq, more preferably 1000 g/eq, particularly preferably 500 g/eq. On the other hand, the lower limit value is preferably 100 g/eq, particularly preferably 200 g/eq.

The radical-polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and the like, with acrylic acid and methacrylic acid being preferred. These radically polymerizable unsaturated monocarboxylic acids may be used alone or in combination of two or more.

The reaction method of the cresol novolac type epoxy resin and the radical polymerizable unsaturated monocarboxylic acid is not particularly limited, and for example, the cresol novolac type epoxy resin and the radical polymerizable unsaturated monocarboxylic acid are heated in a suitable diluent. The reaction can be carried out by

The polybasic acid or polybasic acid anhydride is for reacting the hydroxyl group generated by the reaction of the cresol novolac type epoxy resin and the radically polymerizable unsaturated monocarboxylic acid, and for introducing a free carboxyl group into the resin. is there. The polybasic acid or its anhydride is not particularly limited, and either saturated or unsaturated can be used. Examples of polybasic acids include succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, and 4-ethyltetrahydrophthalic acid. Ethyl tetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, methyltetrahydrophthalic acid, methylhexahydro Examples thereof include phthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid and diglycolic acid, and examples of polybasic acid anhydrides include anhydrides thereof. These compounds may be used alone or in combination of two or more.

In the present invention, the polybasic acid-modified unsaturated monocarboxylic oxide cresol novolac type epoxy resin described above can also be used as the carboxyl group-containing photosensitive resin, but if necessary, the polybasic acid-modified unsaturated monocarboxylic oxide cresol novolac is used. By reacting a glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group with the carboxyl group of the epoxy resin of the epoxy type, radically polymerizable unsaturated groups were further introduced to further improve the photosensitivity. It may be a photosensitive resin containing a carboxyl group.

The carboxyl group-containing photosensitive resin with further improved photosensitivity is a radically polymerizable unsaturated group due to the reaction of the glycidyl compound, in which the polybasic acid-modified unsaturated monocarboxylic oxide cresol novolac type epoxy resin has a side chain. Since they are bonded, they have high photopolymerization reactivity and can have more excellent photosensitivity. Examples of the compound having one or more radically polymerizable unsaturated groups and an epoxy group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, and pentaerythritol trimethacrylate monoglycidyl ether. Can be mentioned. In addition, you may have multiple glycidyl groups in 1 molecule. The above-mentioned compounds having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone or in combination of two or more.

Further, as a carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton, an acid modified urethane-modified unsaturated monocarboxylic acid cresol novolac type epoxy resin such as acid-modified urethane-modified cresol novolac type epoxy (meth)acrylate resin is used. May be. The acid-modified urethane-modified unsaturated monocarboxylic oxide cresol novolac type epoxy resin is prepared by first obtaining a radically polymerizable unsaturated monocarboxylic oxide cresol novolac type epoxy resin such as cresol novolac type epoxy (meth)acrylate as described above. It can be obtained by reacting the above hydroxyl group with the above-mentioned polybasic acid or its anhydride and a compound having two or more isocyanate groups in one molecule.

The compound having two or more isocyanate groups in one molecule is not particularly limited, and examples thereof include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylenebiscyclohexyl isocyanate, Diisocyanates such as trimethylhexamethyldiisocyanate, hexanediisocyanate, hexamethylaminediisocyanate, methylenebiscyclohexylisocyanate, toluenediisocyanate, 1,2-diphenylethanediisocyanate, 1,3-diphenylpropanediisocyanate, diphenylmethanediisocyanate and dicyclohexylmethyldiisocyanate can be mentioned. These compounds may be used alone or in combination of two or more.

In the present invention, the acid-modified urethane-modified cresol novolac type epoxy (meth)acrylate resin and the like acid-modified urethane-modified unsaturated monocarboxylic acid cresol novolac type epoxy resin can also be used as the carboxyl group-containing photosensitive resin, but it is necessary. Accordingly, by reacting the carboxyl group of the acid-modified urethane-modified unsaturated monocarboxylic oxide cresol novolac type epoxy resin described above with a glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group described above, A carboxyl group-containing photosensitive resin having further improved photosensitivity may be obtained by further introducing a radically polymerizable unsaturated group.

As the carboxyl group-containing photosensitive resin, a carboxyl group-containing photosensitive resin having no cresol novolac type epoxy resin skeleton may be contained in the carboxyl group-containing photosensitive resin in an amount of less than 40% by mass. The carboxyl group-containing photosensitive resin having no cresol novolac type epoxy resin skeleton is not particularly limited, and for example, instead of the cresol novolac type epoxy resin, other polyfunctional epoxy resin can be obtained in the same manner as above. You can

The other polyfunctional epoxy resin is not particularly limited, and examples thereof include biphenylaralkyl type epoxy resin, phenylaralkyl type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin. Resin, ε-caprolactone modified epoxy resin, phenol novolac type epoxy resin such as bisphenol A type, bisphenol F type, bisphenol AD type, bisphenol A novolac type epoxy resin, cycloaliphatic polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy resin , Glycidyl amine type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol modified novolac type epoxy resin, polyfunctional modified novolac type epoxy resin, condensate type epoxy resin of phenol and aromatic aldehyde having phenolic hydroxyl group Etc. can be mentioned.

In addition, as the carboxyl group-containing photosensitive resin having no cresol novolac type epoxy resin skeleton, acid-modified urethane-modified unsaturated monocarboxylic oxide epoxy resin such as acid-modified urethane-modified epoxy (meth)acrylate resin (however, cresol novolac-type epoxy resin Except) may be used. The acid-modified urethanated unsaturated monocarboxylic oxide epoxy resin (excluding cresol novolak type) is also used as described above for radical-polymerizable unsaturated monocarboxylic oxide epoxy resin such as epoxy (meth)acrylate (excluding cresol novolak type). (Excluding the type), and the generated hydroxyl group is reacted with the above-described polybasic acid or its anhydride and a compound having two or more isocyanate groups in one molecule.

The carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton is not particularly limited as long as it is 60% by mass or more based on the total mass of the carboxyl group-containing photosensitive resin, but it further improves the flux cleaning liquid resistance. To 80 mass% or more is preferable, 90 mass% or more is more preferable, and 100 mass% is particularly preferable.

The acid value of the carboxyl group-containing photosensitive resin contained in the photosensitive resin composition is not particularly limited, but the lower limit thereof is preferably 30 mgKOH/g, and particularly preferably 40 mgKOH/g, from the viewpoint of reliable alkali development. On the other hand, the upper limit of the acid value is preferably 200 mgKOH/g from the viewpoint of preventing dissolution of the exposed area with an alkali developing solution, and particularly preferably 150 mgKOH/g from the viewpoint of preventing moisture resistance of cured products and deterioration of electrical properties.

The mass average molecular weight of the carboxyl group-containing photosensitive resin contained in the photosensitive resin composition is not particularly limited, but its lower limit is preferably 4000 from the viewpoint of toughness and dryness to the touch of the cured product, 6000 is especially preferred. On the other hand, the upper limit of the mass average molecular weight is preferably 200,000, and particularly preferably 50,000 from the viewpoint of smooth alkali developability.

(B) Photopolymerization Initiator The photopolymerization initiator is not particularly limited as long as it is generally used, and any one can be used. Specifically, for example, 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone 1-[9-ethyl-6-(2-methylbenzoyl)- 9H-carbazol-3-yl]-1-(0-acetyloxime), (Z)-(9-ethyl-6-nitro-9H-carbazol-3-yl)(4-((1-methoxypropane-2 -Yl)oxy)-2-methylphenyl)methanone O-acetyloxime, 2-(acetyloxyiminomethyl)thioxanthen-9-one, 1,8-octanedione, 1,8-bis[9-ethyl-6 -Nitro-9H-carbazol-3-yl]-,1,8-bis(O-acetyloxime),1,8-octanedione,1,8-bis[9-(2-ethylhexyl)-6-nitro- 9H-carbazol-3-yl]-,1,8-bis(O-acetyloxime), (Z)-(9-ethyl-6-nitro-9H-carbazol-3-yl)(4-((1- Methoxypropan-2-yl)oxy)-2-methylphenyl)methanone Oxime ester compounds such as O-acetyloxime, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzoin, benzoin methyl ether, benzoin Ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-methyl-4 '-(Methylthio)-2-morpholinopropiophenone, 2-benzyl-2-methylamino-1-(4-morpholinophenyl)-butanone-1,2-hydroxy-2-methyl-1-phenylpropane-1 -One, 1-hydroxycyclohexyl phenyl ketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthio Oxa And benzyl dimethyl ketal, acetophenone dimethyl ketal, and P-dimethylaminobenzoic acid ethyl ester. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, and is preferably 0.1 parts by mass to 20 parts by mass, and 0.2 parts by mass to 10 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content). Part by weight is especially preferred.

(C) Reactive Diluent The reactive diluent is, for example, a photopolymerizable monomer and is a compound having at least one polymerizable double bond per molecule, preferably at least two per molecule. The reactive diluent is used in order to sufficiently photo-cure the photosensitive resin composition and to obtain a cured product having acid resistance, heat resistance, alkali resistance and the like.

The reactive diluent is not particularly limited as long as it is a compound having a chemical structure having no urethane bond, and examples thereof include 2-hydroxyethyl methacrylate, phenoxyethyl methacrylate, diethylene glycol monomethacrylate, and 2-hydroxy-3. -Phenoxypropyl acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol adipate Di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified phosphoric acid di(meth)acrylate, allyl Cyclohexyldi(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate Examples thereof include acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate. These may be used alone or in combination of two or more.

The reactive diluent is preferably a pentafunctional or higher-functional (meth)acrylate compound from the viewpoint of surely improving the heat resistance of the cured product. Propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate Acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate are more preferable, and dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate are particularly preferable.

The content of the reactive diluent is not particularly limited, and for example, 2.0 to 100 parts by mass is preferable, and 10 to 50 parts by mass is particularly preferable with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content). preferable.

(D) Epoxy compound The epoxy compound is for increasing the crosslink density of the cured product to obtain a cured product having sufficient strength, and examples thereof include an epoxy resin. Examples of the epoxy resin include biphenyl type epoxy resin, phenol aralkyl type epoxy resin, dimer acid type epoxy resin, bisphenol A type epoxy resin, novolac type epoxy resin (phenol novolac type epoxy resin, o-cresol novolac type epoxy resin, p -Tert-butylphenol novolac type), bisphenol F type or bisphenol S type epoxy resin obtained by reacting bisphenol F or bisphenol S with epichlorohydrin, and further has cyclohexene oxide group, tricyclodecane oxide group, cyclopentene oxide group, etc. Alicyclic epoxy resin, triazine(2,3-epoxypropyl)isocyanurate, triglycidyl tris(2-hydroxyethyl)isocyanurate, etc. triazine ring-containing triazine ring-containing epoxy compound, dicyclo Pentadiene type epoxy resin and adamantane type epoxy resin can be mentioned. These compounds may be used alone or in combination of two or more.

Of these, at least 2 of the biphenyl type epoxy resin, the phenol aralkyl type epoxy resin, the dimer acid type epoxy resin, and the triazine ring-containing epoxy compound are used in order to improve the flux cleaning liquid resistance, flexibility and heat resistance in a well-balanced manner. It is preferable to include a seed, and from the viewpoint of further improving the flux cleaning liquid resistance, flexibility and heat resistance, any of the biphenyl type epoxy resin, the phenol aralkyl type epoxy resin, the dimer acid type epoxy resin and the epoxy compound having a triazine ring are included. It is particularly preferable to include. The content of the epoxy compound is not particularly limited and is, for example, preferably 10 to 100 parts by mass and particularly preferably 20 to 60 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content).

In the photosensitive resin composition of the present invention, (E) organic filler may be blended if necessary. By containing the organic filler, flexibility (flexibility) can be imparted to the cured product in addition to the flux cleaning liquid resistance.

The organic filler is an organic compound that is solid at room temperature and atmospheric pressure, and is hardly soluble or insoluble in organic solvents and water. In addition, the organic filler is dispersed in the photosensitive resin composition of the present invention and is hardly soluble or insoluble in the photosensitive resin composition of the present invention. Examples of the organic filler include urethane resins (polymers of isocyanate and polyol), acrylic resins, polyethylene, copolymers of styrene and butadiene such as styrene/butadiene rubber, and polymers of silicone resins such as silicone rubber. be able to.

The shape of the organic filler is not particularly limited, but a particulate shape is preferable. The average particle diameter of the organic filler particles is not particularly limited, but the lower limit value thereof is preferably 0.1 μm from the viewpoint of imparting excellent flexibility to the cured product, and in the production of the photosensitive resin composition of the present invention. From the viewpoint of kneading property, 1.0 μm is particularly preferable. On the other hand, the upper limit of the average particle diameter of the organic filler particles is preferably 30 μm, and particularly preferably 10 μm, from the viewpoint of obtaining a fine line shape. The average particle size is a value measured by a laser diffraction type particle size distribution measuring method. The organic filler may be used alone or in combination of two or more.

The content of the organic filler is not particularly limited, but its lower limit is preferably 10 parts by mass from the viewpoint of reliably imparting flexibility to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content), From the viewpoint of further improving the property, 20 parts by mass is more preferable, and 30 parts by mass is particularly preferable. On the other hand, the upper limit thereof is preferably 200 parts by mass from the viewpoint of kneadability during the production of the photosensitive resin composition of the present invention, more preferably 150 parts by mass from the viewpoint of heat resistance, and particularly preferably 100 parts by mass. ..

In the photosensitive resin composition of the present invention, in addition to the components (A) to (E), various components such as an ion catcher (inorganic ion exchanger), a colorant, an extender pigment, and A flame retardant, a defoaming agent, a non-reactive diluent, an additive and the like can be added.

Since the ion catcher takes in ions, it traps and fixes the impurities of the ions remaining in the photosensitive resin composition of the present invention, and at the same time, it fixes and fixes the metal ions that become ions and move by applying a voltage. This can prevent the occurrence of the ion migration phenomenon in the cured product of the photosensitive resin composition. By preventing the occurrence of the ion migration phenomenon, for example, a solder-resist film formed by applying the photosensitive resin composition of the present invention to a flexible printed wiring board can exhibit excellent insulation reliability. it can.

Examples of the ion catcher include a cation catcher (inorganic cation exchanger), and specific examples of the cation catcher include at least one selected from the group consisting of antimony, bismuth, zirconium, titanium, tin, magnesium and aluminum. An oxide of one element can be mentioned.

The content of the ion catcher is not particularly limited, but its lower limit value is 1.0 part by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content) in order to reliably improve the insulation reliability. 2.5 parts by mass are particularly preferable from the viewpoint of the balance between insulation reliability and flexibility. On the other hand, the upper limit is preferably 40 parts by mass from the viewpoint of surely preventing deterioration of the flexibility of the cured product, and more preferably 20 parts by mass from the viewpoint of the balance between insulation reliability and flexibility, further improving the balance. From the viewpoint of making it possible, 10 parts by mass is particularly preferable.

The colorant is not particularly limited, for example, as a white colorant, an inorganic pigment such as titanium oxide, as a colorant other than white, a green colorant such as phthalocyanine green, a blue colorant such as phthalocyanine blue, anthraquinone-based And organic pigments such as yellow colorants, and inorganic pigments such as black colorants such as carbon black.

The extender pigment contributes to increase the physical strength of the coating film of the photosensitive resin composition, and examples thereof include talc, barium sulfate, silica, alumina, aluminum hydroxide and mica.

The flame retardant is not particularly limited, and known ones can be used. Examples of the flame retardant include phosphorus element-containing compounds. Specific examples of the phosphorus-containing compound include tris(chloroethyl)phosphate, tris(2,3-dichloropropyl)phosphate, tris(2-chloropropyl)phosphate, tris(2,3-bromopropyl)phosphate, tris(bromo). Halogen-containing phosphoric acid such as chloropropyl)phosphate, 2,3-dibromopropyl-2,3-chloropropylphosphate, tris(tribromophenyl)phosphate, tris(dibromophenyl)phosphate, tris(tribromoneopentyl)phosphate Esters: Non-halogenated aliphatic phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate; triphenyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, tricresyl phosphate, trixylyl ester Nylphosphate, xylenyldiphenylphosphate, tris(isopropylphenyl)phosphate, isopropylphenyldiphenylphosphate, diisopropylphenylphenylphosphate, tris(trimethylphenyl)phosphate, tris(t-butylphenyl)phosphate, hydroxyphenyldiphenylphosphate, octyldiphenylphosphate , 3-glycidyloxypropylenediphenylphosphine oxide, 3-glycidyloxydiphenylphosphine oxide, diphenylvinylphosphine oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 2-(9,10-dihydro-9-oxa-10-oxide-10-phosphaphenanthrene-10-yl)methylsuccinic acid bis-(2-hydroxyethyl)-ester polymer and other non-halogenated aromatic phosphate esters Aluminum trisdiethylphosphinate, aluminum diethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, Titanium tetrakisdiethylphosphinate, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titan bisdiphenylphosphinate Cylindrical or linear phosphazene system having a substituted or unsubstituted phenoxy group or a substituted or unsubstituted naphthoxy group, such as metal salts of phosphinic acids such as nyl and tetrakisdiphenylphosphinic acid titanium, cyclic phenoxyphosphazenes, and cyclic cyanophenoxyphosphazenes Examples thereof include compounds and triallylphosphine. These compounds may be used alone or in combination of two or more.

Examples of the defoaming agent include silicone type, hydrocarbon type and acrylic type.

The non-reactive diluent is for adjusting the drying property and coating viscosity of the photosensitive resin composition, and examples thereof include organic solvents. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether. Glycol ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, and triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene Examples thereof include esters such as glycol monomethyl ether acetate and esterified products of the above glycol ethers; alcohols such as ethanol, propanol, ethylene glycol and propylene glycol.

As additives, latent curing agents such as dicyandiamide (DICY) and its derivatives, melamine and its derivatives, imidazoles such as 2-mercaptobenzimidazole, imidazolium salts, heat curing accelerators such as triethanolamine borate, silanes. Examples of the coupling agent include a system-based, titanate-based, and alumina-based coupling agent.

The method for producing the above-mentioned photosensitive resin composition is not limited to a particular method, but for example, it can be produced by mixing the above-mentioned components in a predetermined ratio and mixing and dispersing with a three-roll at room temperature. Moreover, you may pre-mix with a stirrer before the said mixing dispersion as needed.

Next, an example of a method of using the photosensitive resin composition of the present invention will be described. Here, a method of applying the photosensitive resin composition of the present invention as an insulating protective film (for example, a solder resist film) of a flexible printed wiring board will be described as an example.

The photosensitive resin composition of the present invention obtained as described above, for example, on a flexible printed wiring board which is a substrate having a circuit pattern formed by etching a copper foil, a screen printing method, a bar coater method, a blade A coating film is formed by applying a desired thickness by a known method such as a coater method, a knife coater method, a roll coater method, a gravure coater method, and a spray coater method. Next, when the photosensitive resin composition contains a non-reactive diluent such as an organic solvent, in order to volatilize the non-reactive diluent, the temperature is set to about 60 to 80° C. for 15 to 60 minutes. Pre-drying with moderate heating is performed to form a tack-free coating film.

Next, a negative film (photomask) having a translucent pattern other than the land of the circuit pattern is brought into close contact with the coating film that has been preliminarily dried, and ultraviolet rays (for example, in a wavelength range of 300 to 400 nm are applied thereto). ) Is irradiated. Then, the coating film is developed by removing the non-exposed region corresponding to the land with a dilute aqueous alkali solution. As a developing method, a spray method, a shower method, or the like is used, and the dilute alkaline aqueous solution used is, for example, a 0.5 to 5 mass% sodium carbonate aqueous solution. Then, post-cure is performed for 20 to 80 minutes with a hot air circulation type dryer at 130 to 170° C. to form an intended insulating protective film such as a solder resist film on the flexible printed wiring board.

Next, examples of the present invention will be described, but the present invention is not limited to these examples unless the gist thereof is exceeded.

Examples 1-14, Comparative Examples 1-3
Photosensitive properties used in Examples 1 to 14 and Comparative Examples 1 to 14 A resin composition was prepared. The numbers in Table 1 below indicate parts by mass. In addition, the blank in Table 1 below means no compounding.

Test Piece Making Step The photosensitive resin composition prepared as described above was applied as follows to make a test piece.
A flexible wiring board substrate with a circuit pattern formed on a polyimide film (Kapton 100H manufactured by Toray DuPont Co., Ltd.): 2 layers (PI: 25 μm, Cu: 12 μm) are surface-treated with dilute sulfuric acid (5% by mass) and then screened. After coating each photosensitive resin composition by a printing method, preliminary drying was performed in a BOX furnace at 80° C. for 20 minutes. After predrying, 100 mJ/cm ² exposure was performed on the coating film by a direct writing exposure device (“Novogo 800” manufactured by Orbotech), followed by development with a 1% by mass sodium carbonate developer at 30° C., and then 150° C. in a BOX furnace. By carrying out post-curing for 40 minutes, a cured coating film was formed on the substrate. The thickness of the cured coating film was 20 to 23 μm.

Evaluation item (1) Flexibility The test piece obtained in the test piece manufacturing step was bent by a mandrel test up to φ10 to 2 mm in units of 1 mm, and the occurrence of cracks in the cured coating film was visually checked. And was observed with an optical microscope of ×200 to evaluate whether or not a crack was generated.
◯: No cracks occurred even at 2 mm Δ: Cracks occurred at 3 mm or more and 9 mm or less ×: Cracks occurred at 10 mm

(2) Flux cleaning liquid resistance After dipping the test piece obtained in the above-mentioned test piece manufacturing step for 10 minutes in a dipropylene glycol-based flux cleaning solution containing diethanolamine heated to 70° C., a land of a cured coating film was obtained. Regarding the external appearance of the part, the presence or absence of stain marks of the flux cleaning liquid was visually confirmed, and then a tape peel test of the cured coating film was performed to confirm the presence or absence of peeling. The judgment criteria are as follows. The flux cleaning liquid resistance was evaluated as ◯ or higher.
◎: No trace of flux cleaning solution stain, no peeling ○: Stain of flux cleaning fluid, no peeling △: Staining of flux cleaning fluid, slight peeling,
×: There is a stain on the flux cleaning liquid, and there is peeling

(3) Heat resistance A test piece coated with rosin-based flux is immersed in a solder bath set at 260°C for 10 seconds, washed with denatured alcohol, and then a tape peel test is performed to remove the cured coating film. The presence or absence was evaluated. The judgment criteria are as follows.
◎: 260° C., 10 seconds, no peeling after 3 immersions ○: 260° C., 10 seconds, no peeling until 2 immersions Δ: 260° C., 10 seconds, no peeling until 1 immersion ×: 260° C., 10 seconds, Peeling after one immersion

The test results of Examples 1 to 14 and Comparative Examples 1 to 3 are shown in Table 1 below.

From Table 1, Examples 1 to 14 in which 60% by mass or more of the carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton is contained in the carboxyl group-containing photosensitive resin and the reactive diluent does not have a urethane bond. Then, the flux cleaning liquid resistance was obtained without impairing the heat resistance. Further, in Examples 1 to 14 in which dipentaerythritol hexaacrylate or caprolactone-modified dipentaerythritol hexaacrylate was used as the reactive diluent, excellent flux cleaning liquid resistance was obtained. Further, from the comparison between Example 1 and Examples 2 to 5, when any of the biphenyl type epoxy compound, the phenol aralkyl type epoxy compound, the dimer acid type epoxy compound and the epoxy compound having a triazine ring is contained, the flux cleaning liquid resistance and the bending resistance are high. It was possible to further improve the heat resistance and heat resistance. Further, from the comparison between Example 3 and Examples 6 and 14, the carboxyl group-containing photosensitive resin is a carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton (that is, cresol in the carboxyl group-containing photosensitive resin. 100% by mass of the carboxyl group-containing photosensitive resin having a novolac type epoxy resin skeleton), and the flux cleaning liquid resistance was further improved.

From comparison between Example 1 and Example 12, when an organic filler was further contained, excellent flexibility was obtained.

On the other hand, in Comparative Example 1 in which the carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton was not used as the carboxyl group-containing photosensitive resin, and Comparative Example 2 in which the reactive diluent having a urethane bond was used. In all cases, no flux cleaning liquid resistance was obtained. Further, in Comparative Example 3 in which the carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton is contained in the carboxyl group-containing photosensitive resin in an amount of 50% by mass, a good flux-proof cleaning liquid is obtained as compared with Examples 1 to 14. The sex was not obtained.

INDUSTRIAL APPLICABILITY The photosensitive resin composition of the present invention can obtain a cured product having excellent flux cleaning liquid resistance, and thus has high utility value particularly in the field of insulating films of substrates on which flux cleaning agents are used.

Claims (5)

A photosensitive resin composition comprising (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound,
The (A) carboxyl group-containing photosensitive resin contains 60 mass% or more of the carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton, and the (C) reactive diluent has no urethane bond. ,
Wherein (D) an epoxy compound, a biphenyl type epoxy compounds, dimer acid type epoxy compound, a phenol aralkyl type epoxy compound and a photosensitive resin composition characterized in that both contain the epoxy compound having a triazine ring. Furthermore, (E) organic filler is contained, The photosensitive resin composition of Claim 1 characterized by the above-mentioned. The said (E) organic filler contains 30-100 mass parts with respect to 100 mass parts of said (A) carboxyl group containing photosensitive resin, The photosensitive resin composition of Claim 2 characterized by the above-mentioned. 4. The photosensitive resin composition according to claim 1, wherein the (C) reactive diluent contains a (meth)acrylate compound having a functionality of 5 or more. The photosensitive resin composition according to claim 4, wherein the pentafunctional or higher poly(meth)acrylate compound is dipentaerythritol hexa(meth)acrylate and/or caprolactone-modified dipentaerythritol hexa(meth)acrylate.