JP2018169608A - Photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition that makes it possible to obtain a cured product having excellent flux cleaning liquid resistance.SOLUTION: A photosensitive resin composition contains (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 a carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton; the (C) reactive diluent contains no urethane bond.SELECTED DRAWING: None

Description

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

  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). As the protective film, a photocured film of a photosensitive resin composition containing a photosensitive resin may be used. In some cases, a solder paste is printed on a substrate on which a protective film is formed, and an electronic component is mounted in a reflow furnace.

  However, the solder paste contains a flux component in order to impart fluidity. In particular, when solder paste is applied by a jet dispenser, more flux components are blended in order to obtain the fluidity of the solder paste. Further, when an electronic component is mounted on a substrate in a reflow furnace, unaggregated metal (solder balls) may remain near the mounting portion. A flux cleaning solution may be used to remove solder balls and flux components remaining in the vicinity of the mounting portion.

  Examples of the flux cleaning liquid include 75.0 to 99.2% by mass of component (A) such as diethylene glycol monoalkyl ether, 0.5 to 10.0% by mass of component (B) that is alkanolamine, and 1 carbon atom. The composition which contains 0.3-5.0 mass% of component (C) which is the alkylbenzenesulfonic acid which has an alkyl group of -6, and / or its salt is mentioned (patent document 1).

  In addition, 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 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 to contain is mentioned (patent document 2).

  On the other hand, if a flux cleaning solution is used to remove solder balls and flux components, the components of the flux cleaning solution may permeate into a protective film such as a solder resist and the protective film may swell or peel off. . Further, when a protective film is formed on the flexible printed wiring board, the protective film is required to have flexibility (flexibility). However, as a result of imparting flexibility to the protective film from the viewpoint of the resin skeleton contained in the photosensitive resin composition, there is a problem that resistance to the flux cleaning liquid is not sufficient. Furthermore, DI exposure (direct drawing exposure) is frequently used from the viewpoint that finer cured films and high resolution are required. The cured coating film photocured by DI exposure is less resistant to flux cleaning solution than the conventional cured film photocured by scattered light, and the cured coating film is more likely to swell and peel off. There was a problem that.

JP 2009-298940 A JP 2002-293882 A

  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.

  An aspect of the present invention is 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% by mass or more of a carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton, and the (C) reactive diluent is a urethane bond. It is the photosensitive resin composition characterized by not having.

  In the said aspect, 60 mass% or more of carboxyl group-containing photosensitive resin which has a cresol novolak-type epoxy resin frame | skeleton is contained in (A) carboxyl group-containing photosensitive resin. Moreover, although 1 type or 2 types or more may be sufficient as the structural component of (C) reactive diluent, all do not have a urethane bond.

  An embodiment of the present invention is a photosensitive resin composition further comprising (E) an organic filler.

  An aspect of the present invention is a photosensitive resin composition in which the (E) organic filler is contained in an amount of 30 to 100 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing photosensitive resin. .

  An aspect of the present invention is a photosensitive resin composition, wherein the reactive diluent (C) includes a pentafunctional or higher functional (meth) acrylate compound.

  An aspect of the present invention is a photosensitive resin composition in which the pentafunctional or higher functional (meth) acrylate compound is dipentaerythritol hexa (meth) acrylate and / or caprolactone-modified dipentaerythritol hexa (meth) acrylate.

  In an embodiment of the present invention, the (D) epoxy compound comprises 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 including.

  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 hardened | cured material excellent in the flux washing | cleaning liquid resistance can be obtained, without impairing basic characteristics, such as heat resistance.

  According to the aspect of the present invention, in addition to (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 flexible printed wiring boards.

  According to the aspect of the present invention, when the (C) reactive diluent contains a pentafunctional or higher (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 includes (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound. A resin composition, wherein the (A) 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, and the (C) reactive diluent is It 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 novolak type epoxy resin skeleton is not particularly limited as long as it has a chemical structure having a cresol novolak type epoxy resin skeleton. For example, a carboxyl group-containing photosensitive resin derived from a cresol novolak type epoxy resin is used. Can be mentioned. Specifically, for example, at least a part of the epoxy group of the cresol novolac type epoxy resin having two or more epoxy groups in one molecule has acrylic acid or methacrylic acid (hereinafter referred to as “(meth) acrylic acid”). Radical polymerizable unsaturated monocarboxylic acid such as cresol novolak type epoxy (meth) acrylate to obtain radical polymerizable unsaturated monocarboxylic oxidized cresol novolak type epoxy resin, Mention may be made of polybasic acid-modified radical-polymerizable unsaturated monocarboxylic cresol-oxidized cresol novolak-type epoxy resins such as polybasic acid-modified cresol novolak type epoxy (meth) acrylates obtained by reacting basic acids or anhydrides thereof.

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

  The radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and acrylic acid and methacrylic acid are preferable. 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. For example, the cresol novolak type epoxy resin and the radical polymerizable unsaturated monocarboxylic acid are heated in an appropriate diluent. It can be made to react by doing.

  The polybasic acid or polybasic acid anhydride reacts with a hydroxyl group produced by the reaction of the cresol novolak type epoxy resin and the radical polymerizable unsaturated monocarboxylic acid, and introduces 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. Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4- Ethyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, methyltetrahydrophthalic acid, methylhexahydro Examples include phthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid, and diglycolic acid. Examples of polybasic acid anhydrides include these anhydrides. These compounds may be used alone or in combination of two or more.

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

  In this carboxyl group-containing photosensitive resin with improved photosensitivity, the radical polymerizable unsaturated group is added to the side chain of the polybasic acid-modified unsaturated monocarboxylic oxide cresol novolac type epoxy resin skeleton by the reaction of the glycidyl compound. 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, pentaerythritol trimethacrylate monoglycidyl ether, and the like. Can be mentioned. In addition, you may have multiple glycidyl groups in 1 molecule. The above-mentioned compound having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone or in combination of two or more.

  In addition, as carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton, acid-modified urethanized unsaturated monocarboxylic oxide cresol novolac type epoxy resin such as acid-modified urethanized cresol novolak type epoxy (meth) acrylate resin is used. May be. The acid-modified urethanized unsaturated monocarboxylic oxide cresol novolak type epoxy resin is obtained by first obtaining a radical polymerizable unsaturated monocarboxylic oxide cresol novolak type epoxy resin such as cresol novolak type epoxy (meth) acrylate as described above. It can be obtained by reacting the above-mentioned polybasic acid or its anhydride with 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. For example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylene biscyclohexyl isocyanate, Examples thereof include diisocyanates such as trimethylhexamethyl diisocyanate, hexane diisocyanate, hexamethylamine diisocyanate, methylenebiscyclohexyl isocyanate, toluene diisocyanate, 1,2-diphenylethane diisocyanate, 1,3-diphenylpropane diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethyl diisocyanate. These compounds may be used alone or in combination of two or more.

  In the present invention, acid-modified urethanized unsaturated monocarboxylic acid-oxidized cresol novolac-type epoxy resins such as the above-mentioned acid-modified urethanized cresol novolak-type epoxy (meth) acrylate resins can also be used as carboxyl group-containing photosensitive resins. Accordingly, by reacting the glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group with the carboxyl group of the acid-modified urethanized unsaturated monocarboxylic oxide cresol novolac type epoxy resin described above, It is good also as a carboxyl group-containing photosensitive resin which introduce | transduced the radically polymerizable unsaturated group further and improved photosensitivity more.

  Moreover, you may contain carboxyl group-containing photosensitive resin which does not have a cresol novolak-type epoxy resin frame | skeleton as carboxyl group-containing photosensitive resin in less than 40 mass% in carboxyl group-containing photosensitive resin. The carboxyl group-containing photosensitive resin not having a cresol novolac type epoxy resin skeleton is not particularly limited. For example, it is obtained in the same manner as described above from another polyfunctional epoxy resin instead of a cresol novolac type epoxy resin. Can do.

  Other polyfunctional epoxy resins are not particularly limited. For example, biphenyl aralkyl type epoxy resins, phenyl aralkyl type epoxy resins, biphenyl type epoxy resins, bisphenol A type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxies. Resin, ε-caprolactone modified epoxy resin, bisphenol A type, bisphenol F type, bisphenol AD type phenol novolac type epoxy resin, bisphenol A novolak type epoxy resin, cycloaliphatic polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy resin , Glycidylamine type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol modified novolak type epoxy resin, polyfunctional modified novolak type epoxy resin, phenols and phenol Condensate type epoxy resin with an aromatic aldehyde having a hydroxyl group can be exemplified.

  In addition, as a carboxyl group-containing photosensitive resin having no cresol novolac epoxy resin skeleton, acid-modified urethanized unsaturated monocarboxylic oxide epoxy resin such as acid-modified urethanized epoxy (meth) acrylate resin (however, cresol novolac type May be used. Acid-modified urethanized unsaturated monocarboxylic oxide epoxy resin (excluding cresol novolak type) is also used for radical polymerizable unsaturated monocarboxylic oxide epoxy resin (however, cresol novolak type) as described above. It is obtained by reacting the above-mentioned polybasic acid or its anhydride with 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% by mass or more is preferable, 90% by mass or more is more preferable, and 100% by 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 is preferably 30 mgKOH / g, particularly preferably 40 mgKOH / g, from the viewpoint of reliable alkaline 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 developer, and particularly preferably 150 mgKOH / g from the viewpoint of preventing moisture resistance of the cured product and preventing deterioration of electrical characteristics.

  The weight average molecular weight of the carboxyl group-containing photosensitive resin contained in the photosensitive resin composition is not particularly limited, but the lower limit is preferably 4000 from the viewpoint of toughness of the cured product and dryness to touch, 6000 is particularly preferred. On the other hand, the upper limit value of the mass average molecular weight is preferably 200000, particularly preferably 50000, 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 of them 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-carbazo Ru-3-yl]-, 1,8-bis (O-acetyloxime), (Z)-(9-ethyl-6-nitro-9H-carbazol-3-yl) (4-((1-methoxypropane -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-morpholinopropio Enone, 2-benzyl-2-methylamino-1- (4-morpholinophenyl) -butanone-1,2-hydroxy-2-methyl-1-phenylpropan-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 -Tertiary butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, a Examples include cetophenone dimethyl ketal and P-dimethylaminobenzoic acid ethyl ester. These may be used alone or in combination of two or more.

  Content of a photoinitiator is not specifically limited, 0.1 mass part-20 mass parts are preferable with respect to 100 mass parts of carboxyl group-containing photosensitive resin (solid content), 0.2 mass part-10 mass parts Part by mass is particularly 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 polymerizable double bonds per molecule. The reactive diluent is used to obtain a cured product having sufficient acid resistance, heat resistance, alkali resistance, etc., by sufficiently photocuring the photosensitive resin composition.

  The reactive diluent is not particularly limited as long as it is a compound having a chemical structure having no urethane bond. For example, 2-hydroxyethyl methacrylate, phenoxyethyl methacrylate, diethylene glycol monomethacrylate, 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, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, Lenoxide modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tri (Meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipenta Examples include erythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

  The reactive diluent is preferably a pentafunctional or higher (meth) acrylate compound from the viewpoint of reliably improving the heat resistance of the cured product. Propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) 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.

  Content of a reactive diluent is not specifically limited, For example, 2.0-100 mass parts is preferable with respect to 100 mass parts of carboxyl group-containing photosensitive resin (solid content), and 10-50 mass parts is especially preferable. preferable.

(D) Epoxy compound An epoxy compound is for obtaining the hardened | cured material of sufficient intensity | strength by raising the crosslinking density of hardened | cured material, For example, an epoxy resin can be mentioned. 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 novolak type epoxy resin, p -Tert-butylphenol novolak type), bisphenol F type and bisphenol S type epoxy resin obtained by reacting bisphenol F and bisphenol S with epichlorohydrin, and further having cyclohexene oxide group, tricyclodecane oxide group, cyclopentene oxide group, etc. Tria such as alicyclic epoxy resin, tris (2,3-epoxypropyl) isocyanurate, triglycidyltris (2-hydroxyethyl) isocyanurate Epoxy compound having a triazine ring such as triglycidyl isocyanurate having an emission ring, dicyclopentadiene type epoxy resins, adamantane type epoxy resin. These compounds may be used alone or in combination of two or more.

  Among these, at least two 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 from the viewpoint of improving the flux cleaning liquid resistance, flexibility and heat resistance in a balanced manner. It is preferable to contain seeds, and from the viewpoint of further improving the flux cleaning solution resistance, flexibility and heat resistance, all 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 It is particularly preferable to include it. Content of an epoxy compound is not specifically limited, For example, 10-100 mass parts is preferable with respect to 100 mass parts of carboxyl group-containing photosensitive resin (solid content), and 20-60 mass parts is especially preferable.

  In the photosensitive resin composition of this invention, you may mix | blend (E) organic filler as needed. By containing the organic filler, flexibility (flexibility) can be imparted to the cured product in addition to the flux cleaning liquid resistance.

  An organic filler is a solid organic compound at normal temperature and pressure, and is hardly soluble or insoluble in an organic solvent 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 organic fillers include urethane resins (polymers of isocyanate and polyol), acrylic resins, polyethylene, copolymers of styrene and butadiene such as styrene / butadiene rubber, and polymers such as silicone resins such as silicone rubber. be able to.

  Although the shape of an organic filler is not specifically limited, A particulate form is preferable. The average particle diameter of the organic filler particles is not particularly limited, but the lower limit is preferably 0.1 μm from the viewpoint of imparting excellent flexibility to the cured product, and is used in the production of the photosensitive resin composition of the present invention. In view of kneadability, 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, particularly preferably 10 μm, from the viewpoint of obtaining a fine line shape. The average particle diameter is a numerical value measured by a laser diffraction particle size distribution measurement 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 the lower limit is preferably 10 parts by mass from the viewpoint of surely imparting flexibility to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content). 20 mass parts is more preferable from the point which improves property more, and 30 mass parts is especially preferable. On the other hand, the upper limit is preferably 200 parts by mass from the viewpoint of kneadability in 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 above components (A) to (E), various components, for example, an ion catcher (inorganic ion exchanger), a colorant, an extender pigment, Flame retardants, antifoaming agents, non-reactive diluents, additives and the like can be blended.

  Since the ion catcher takes in ions, the ion impurities remaining in the photosensitive resin composition of the present invention are captured and fixed, and when a voltage is applied, metal ions that move and become ions are captured and fixed. Thereby, generation | occurrence | production of the ion migration phenomenon in the hardened | cured material of the photosensitive resin composition can be prevented. 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 selected from the group consisting of antimony, bismuth, zirconium, titanium, tin, magnesium, and aluminum. Mention may be made of oxides of one element.

  The content of the ion catcher is not particularly limited, but the lower limit is 1.0 part by mass from the viewpoint of surely improving the insulation reliability with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content). 2.5 parts by mass is 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 reliably preventing a decrease in flexibility of the cured product, more preferably 20 parts by mass from the viewpoint of the balance between insulation reliability and flexibility, and the above balance is further improved. 10 parts by mass is particularly preferable from the viewpoint of making it.

  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, an anthraquinone series Examples thereof include organic pigments such as yellow colorants such as inorganic pigments, and inorganic pigments such as black colorants such as carbon black.

  The extender pigment contributes to increasing 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.

  A flame retardant is not specifically limited, A well-known thing can be used. Examples of the flame retardant include a phosphorus element-containing compound. Specific examples of the phosphorus element-containing compound include tris (chloroethyl) phosphate, tris (2,3-dichloropropyl) phosphate, tris (2-chloropropyl) phosphate, tris (2,3-bromopropyl) phosphate, tris (bromo). Halogenated phosphoric acid such as chloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropyl phosphate, tris (tribromophenyl) phosphate, tris (dibromophenyl) phosphate, tris (tribromoneopentyl) phosphate Esters; non-halogen aliphatic phosphate esters such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate; triphenyl phosphate Cresyl diphenyl phosphate, dicresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, xylenyl diphenyl phosphate, tris (isopropylphenyl) phosphate, isopropylphenyl diphenyl phosphate, diisopropylphenylphenyl phosphate, tris (trimethylphenyl) phosphate, Tris (t-butylphenyl) phosphate, hydroxyphenyl diphenyl phosphate, octyl diphenyl phosphate, 3-glycidyloxypropylene diphenylphosphine oxide, 3-glycidyloxydiphenylphosphine oxide, diphenylvinylphosphine oxide, 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphafe Non-halogens such as entolen-10-oxide, 2- (9,10-dihydro-9-oxa-10-oxide-10-phosphaphenanthrene-10-yl) methylsuccinic acid bis- (2-hydroxyethyl) -ester polymer Aromatic phosphoric acid ester; aluminum trisdiethylphosphinate, aluminum diethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, Bisdiethylphosphinate titanyl, tetrakisdiethylphosphinate titanium, bismethylethylphosphinate titanyl, tetrakismethylethylphosphinate titanium, bisdiphenylphosphinate tita Cyclic, chain phosphazene systems having substituted or unsubstituted phenoxy groups or substituted or unsubstituted naphthoxy groups, such as metal salts of phosphinic acids such as titanium, tetrakisdiphenylphosphinate, cyclic phenoxyphosphazenes, and cyclic cyanophenoxyphosphazenes A compound, triallylphosphine, and the like. These compounds may be used alone or in combination of two or more.

  Examples of antifoaming agents include silicones, hydrocarbons, and acrylics.

  The non-reactive diluent is for adjusting the drying property and coating viscosity of the photosensitive resin composition, and examples thereof include an organic solvent. 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, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene Glycol monomethyl ether acetate and the above Esters such as esters of calls ethers; ethanol, can be mentioned propanol, ethylene glycol, and alcohols such as propylene glycol.

  Additives include dicyandiamide (DICY) and its derivatives, latent curing agents such as melamine and its derivatives, imidazoles such as 2-mercaptobenzimidazole, imidazolium salts, thermosetting accelerators such as triethanolamine borate, silane Examples include coupling agents such as those based on titanate, titanate, and alumina.

  Although the manufacturing method of the above-mentioned photosensitive resin composition is not limited to a specific method, For example, after mix | blending each said component by a predetermined ratio, it can mix and disperse | distribute with a three roll at room temperature. Moreover, you may pre-mix with a stirrer before the said mixing dispersion | distribution as needed.

  Next, the usage example of the photosensitive resin composition of this invention is demonstrated. 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 is subjected to, for example, a screen printing method, a bar coater method, a blade on a flexible printed wiring board which is a substrate having a circuit pattern formed by etching a copper foil. A coating film is formed by coating at a desired thickness by a known method such as a coater method, a knife coater method, a roll coater method, a gravure coater method, or a spray coater method. Next, when the non-reactive diluent such as an organic solvent is contained in the photosensitive resin composition, in order to volatilize the non-reactive diluent, the temperature is about 60 to 80 ° C. for 15 to 60 minutes. Pre-drying is performed to a certain degree to form a tack-free coating film.

  Next, a negative film (photomask) having a light-transmitting pattern other than the circuit pattern land is brought into close contact with the pre-dried coating film, and ultraviolet light (for example, in a wavelength range of 300 to 400 nm) is formed thereon. ). Then, the coating film is developed by removing the non-exposed areas corresponding to the lands with a dilute alkaline aqueous solution. As the developing method, a spray method, a shower method, or the like is used, and examples of the diluted alkaline aqueous solution to be used include 0.5 to 5% by mass of an aqueous sodium carbonate solution. Subsequently, by performing post-cure for 20 to 80 minutes with a hot air circulation dryer or the like at 130 to 170 ° C., a desired insulating protective film such as a solder resist film can be formed on the flexible printed wiring board.

  Next, examples of the present invention will be described. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Examples 1-14, Comparative Examples 1-3
Each component shown in the following Table 1 is blended at a ratio shown in the following Table 1, mixed and dispersed at room temperature using three rolls, and used in Examples 1 to 14 and Comparative Examples 1 to 3. A resin composition was prepared. The numbers in Table 1 below indicate parts by mass. Moreover, the blank in Table 1 below means no blending.

Test piece preparation process The photosensitive resin composition prepared as mentioned above was applied as follows, and the test piece was produced.
Substrate for flexible wiring board having a circuit pattern formed on a polyimide film (Kapton 100H manufactured by Toray DuPont Co., Ltd.): Two layers (PI: 25 μm, Cu: 12 μm) are surface-treated with dilute sulfuric acid (5% by mass), and then screened After applying each photosensitive resin composition by a printing method, preliminary drying was performed at 80 ° C. for 20 minutes in a BOX furnace. After preliminary drying, the coating film was exposed to 100 mJ / cm ² with a direct drawing exposure apparatus (Orbotech “Nuvogo 800”), developed with 1% by weight sodium carbonate developer at 30 ° C., and then 150 ° C. with a BOX furnace. A cured coating film was formed on the substrate by post-curing for 40 minutes. The thickness of the cured coating film was 20-23 μm.

Evaluation item (1) Flexibility The test piece obtained in the above-mentioned test piece preparation step is bent in units of 1 mm from φ10 to 2 mm by a mandrel test, and the occurrence of cracks in the cured coating film is visually observed. And it observed with the optical microscope of * 200, and evaluated whether the crack generate | occur | produced.
○: Crack does not occur even at 2 mm Δ: Crack occurs at 3 mm or more and 9 mm or less ×: Crack occurs at 10 mm

(2) Resistance to flux cleaning solution After immersing the test piece obtained in the test piece preparation step for 10 minutes in a dipropylene glycol-based flux cleaning solution containing diethanolamine heated to 70 ° C, the cured coating land About the part external appearance, the presence or absence of the infiltration trace of a flux washing | cleaning liquid was confirmed visually, and the tape peel test of the cured coating film was done after that, and the presence or absence of peeling was confirmed. The judgment criteria are as follows. In addition, regarding the flux cleaning liquid resistance, an evaluation of ◯ or higher was regarded as acceptable.
◎: There is no trace of flux cleaning liquid soaking, no peeling ○: There is soaking trace of flux cleaning liquid, no peeling △: There is soaking trace of flux cleaning liquid, some peeling,
×: There is a trace of the flux cleaning liquid soaked, 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 in advance, and after washing the flux with denatured alcohol, a tape peel test is conducted to remove the cured coating film. The presence or absence was evaluated. The judgment criteria are as follows.
A: 260 ° C., 10 seconds, no detachment after 3 immersions ○: 260 ° C., 10 seconds, no detachment until 2 times immersion Δ: 260 ° C., 10 seconds, no detachment until 1 time immersion x: 260 ° C., 10 seconds, There is 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 1-14 in which the carboxyl group-containing photosensitive resin which has a cresol novolak-type epoxy resin frame | skeleton in a carboxyl group-containing photosensitive resin is contained 60 mass% or more, and a 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 comparison between Example 1 and Examples 2 to 5, when any of a biphenyl type epoxy compound, a phenol aralkyl type epoxy compound, a dimer acid type epoxy compound and an epoxy compound having a triazine ring is included, the flux cleaning liquid resistance, the bending And heat resistance could be further improved. Further, from comparison between Example 3 and Examples 6 and 14, the carboxyl group-containing photosensitive resin is composed of a carboxyl group-containing photosensitive resin having a cresol novolac type epoxy resin skeleton (that is, cresol in the carboxyl group-containing photosensitive resin). And 100% by mass of a carboxyl group-containing photosensitive resin having a novolac-type epoxy resin skeleton) and the flux cleaning solution resistance was further improved.

  Moreover, when the organic filler was further contained from the comparison between Example 1 and Example 12, excellent flexibility was obtained.

  On the other hand, in Comparative Example 1 in which a carboxyl group-containing photosensitive resin having a cresol novolak type epoxy resin skeleton was not used as a carboxyl group-containing photosensitive resin, and in Comparative Example 2 in which a reactive diluent having a urethane bond was used. In either case, the flux cleaning solution resistance was not obtained. Further, in Comparative Example 3 in which 50% by mass of the carboxyl group-containing photosensitive resin having a cresol novolak-type epoxy resin skeleton is contained in the carboxyl group-containing photosensitive resin, compared to Examples 1 to 14, a better anti-flux cleaning solution Sex was not obtained.

  Since the photosensitive resin composition of this invention can obtain the hardened | cured material excellent in the flux washing | cleaning liquid-proof property, the utility value is high especially in the field | area of the insulating film of the board | substrate in which a flux washing | cleaning agent is used.

Claims (6)

(A) A photosensitive resin composition containing 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% by mass or more of a carboxyl group-containing photosensitive resin having a cresol novolak type epoxy resin skeleton, and the (C) reactive diluent does not have a urethane bond. The photosensitive resin composition characterized by the above-mentioned.   The photosensitive resin composition according to claim 1, further comprising (E) an organic filler.   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.   The photosensitive resin composition according to claim 1, wherein the (C) reactive diluent contains a (meth) acrylate compound having five or more functional groups.   The photosensitive resin composition according to claim 4, wherein the pentafunctional or higher functional (meth) acrylate compound is dipentaerythritol hexa (meth) acrylate and / or caprolactone-modified dipentaerythritol hexa (meth) acrylate.   The (D) epoxy compound includes 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. The photosensitive resin composition of any one of Claims 1 thru | or 5.