JP6596550B2 - Photosensitive resin composition, dry film coated with photosensitive resin composition, and printed wiring board having photocured film of photosensitive resin composition - Google Patents

Description

  The present invention relates to a photosensitive resin composition having an excellent line shape and capable of obtaining a cured coating film having excellent elongation characteristics, a dry film coated with the photosensitive resin composition, and the photosensitive resin. The present invention relates to a printed wiring board having a photocured film of the composition.

  A protective film (for example, an insulating film) may be formed on a substrate (for example, a substrate on which a conductor circuit pattern is formed). Examples of the substrate on which the conductor circuit pattern is formed include a printed wiring board using a flexible substrate or a rigid substrate. A photocured film of a photosensitive resin composition containing a photosensitive resin may be used as a protective film for a printed wiring board.

  As electronic devices have become more sophisticated in recent years, electronic components are mounted on printed wiring boards at high density, so the protective film of printed wiring boards has a shape that prevents undercutting even for fine lines. That is, it is required to have good resolution. Further, among the printed wiring boards, a flexible printed wiring board using a flexible substrate such as polyimide is required to have an excellent elongation characteristic because the protective film is required to be flexible.

  Therefore, in Patent Document 1, in order to provide a cured coating film having excellent flexibility, (A) a photosensitive prepolymer having two or more unsaturated double bonds and one or more carboxyl groups in one molecule; (B) Photopolymerization initiator, (C) Diluent, (D) Epoxy compound, (E) Polybutadiene having one or more internal epoxide groups in one molecule, and (F) Photosensitive resin containing polyurethane fine particles Compositions have been proposed.

  However, Patent Document 1 still has room for improvement in elongation characteristics, and there is a problem that an excellent line shape in which undercut is prevented cannot be sufficiently obtained.

JP 2002-293882 A

  In view of the above circumstances, the present invention provides a photosensitive film having an excellent line shape in which undercut is prevented without impairing basic characteristics such as dryness to touch and capable of obtaining a cured coating film having excellent elongation characteristics. It aims at providing the printed wiring board which has a photosensitive resin composition, the dry film with which this photosensitive resin composition was coated, and the photocuring film | membrane of this photosensitive resin composition.

  Embodiments of the present invention include: (A) a) an epoxy resin having two or more epoxy groups in one molecule; b) at least one saturated monocarboxylic acid having 5 to 17 carbon atoms; and c) a dicarboxylic acid. d) Carboxylic group-containing photosensitivity obtained by adding e) polybasic acid and / or polybasic acid anhydride to unsaturated carboxylated epoxy resin, which is a reaction product with ethylenically unsaturated group-containing carboxylic acid. A photosensitive resin composition comprising a resin and (B) a photopolymerization initiator.

  An aspect of the present invention is a photosensitive resin composition, wherein the b) at least one saturated monocarboxylic acid having 5 to 17 carbon atoms is linear.

  An aspect of the present invention is a photosensitive resin composition, wherein the c) dicarboxylic acid contains at least one dicarboxylic acid having 6 to 20 carbon atoms.

  An aspect of the present invention is a photosensitive resin composition, wherein the c) dicarboxylic acid contains at least one dicarboxylic acid having 6 to 10 carbon atoms.

In an embodiment of the present invention, e) the polybasic acid and / or polybasic acid anhydride is a polybasic acid anhydride, and the polybasic acid anhydride is represented by the following general formula (1):
(In the formula, R ² represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, an aryl group, a carboxyl group, or a hydroxyl group, and m is an integer of 1 to 3). It is a photosensitive resin composition characterized by being represented by these.

  The aspect of this invention is a photosensitive resin composition characterized by containing the (C) (meth) acrylate monomer further.

  An embodiment of the present invention is a photosensitive resin composition further comprising (D) an epoxy compound.

  An aspect of the present invention is a dry film in which the photosensitive resin composition is coated on a film.

  An aspect of the present invention is a printed wiring board having a photocured film obtained by patterning a coating film formed by laminating the dry film on a substrate.

  An aspect of the present invention is a printed wiring board having a photocured film obtained by patterning a coating film formed by applying the photosensitive resin composition on a substrate.

  According to an aspect of the present invention, a photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin and (B) a photopolymerization initiator, wherein (A) the carboxyl group-containing photosensitive resin is A) an epoxy resin having two or more epoxy groups in one molecule, b) at least one saturated monocarboxylic acid having 5 to 17 carbon atoms, c) a dicarboxylic acid, and d) an ethylenically unsaturated group Excellent transparency and touch by having a chemical structure obtained by adding e) polybasic acid and / or polybasic acid anhydride to unsaturated carboxylic oxide epoxy resin which is a reaction product with carboxylic acid A photosensitive resin composition having a drying property can be obtained, and a cured coating film having excellent resolution and elongation properties can be obtained by obtaining an excellent line shape in which undercut is prevented. Can do.

  Moreover, according to the aspect of the present invention, a medium chain to long chain monocarboxylic acid (a saturated monocarboxylic acid having 5 to 17 carbon atoms) having a structure excellent in transparency, elongation characteristics, insulation reliability, and hydrophobicity. Is added to an epoxy resin having two or more epoxy groups in one molecule together with an ethylenically unsaturated group-containing carboxylic acid, so that photocurability, transparency, elongation characteristics, insulation reliability, combustion resistance and hydrophobicity A cured coating film having excellent properties can be formed. Further, by adding a polybasic acid and / or polybasic acid anhydride and introducing a carboxyl group into the resin, it can be solubilized in a weak alkaline aqueous solution (for example, an aqueous sodium carbonate solution, an aqueous potassium carbonate solution, etc.). Further, developability can be imparted to the resin composition.

  According to the aspect of the present invention, by adding a dicarboxylic acid to an epoxy resin having two or more epoxy groups in one molecule, different epoxy groups of the epoxy resin that is a constituent component of the carboxyl group-containing photosensitive resin, By bonding to each other via the dicarboxylic acid, a relatively rigid skeleton of the epoxy resin is crosslinked by a covalent bond with a flexible skeleton derived from the dicarboxylic acid. Thereby, an elongation characteristic can be provided to the cured coating film of the photosensitive resin composition of the present invention. In addition, by introducing a dicarboxylic acid into the carboxyl group-containing photosensitive resin, it is possible to adjust the relatively low molecular weight epoxy resin to an appropriate molecular weight, so that touch drying after drying while maintaining alkali developability is possible. It can be set as the photosensitive resin composition used as the cured coating film excellent in the property.

  According to the aspect of the present invention, by including a medium chain to long chain dicarboxylic acid having 6 to 10 carbon atoms as the dicarboxylic acid, the transparency of the photosensitive resin composition is further improved, and the undercut is more reliably performed. Accordingly, a cured coating film having a more excellent line shape (that is, having excellent resolution) can be obtained. Moreover, the touch-drying property of the photosensitive resin composition further improves by including medium-chain to long-chain dicarboxylic acid having 6 to 10 carbon atoms as dicarboxylic acid.

  Next, the photosensitive resin composition of the present invention will be described in detail. The photosensitive resin composition of the present invention comprises (A) a) an epoxy resin having two or more epoxy groups in one molecule, b) at least one saturated monocarboxylic acid having 5 to 17 carbon atoms, and c. Carboxyl) obtained by adding e) polybasic acid and / or polybasic acid anhydride to unsaturated carboxylated epoxy resin, which is a reaction product of d) dicarboxylic acid and d) ethylenically unsaturated group-containing carboxylic acid A group-containing photosensitive resin and (B) a photopolymerization initiator are contained. Each of the above components is as follows.

(A) Carboxyl group-containing photosensitive resin a) Epoxy resin having two or more epoxy groups in one molecule If the epoxy resin having two or more epoxy groups in one molecule is a bifunctional or more functional epoxy resin Either can be used. The epoxy equivalent of an epoxy resin having two or more epoxy groups in one molecule is not particularly limited, but the upper limit is a decrease in the introduction ratio of ethylenically unsaturated group-containing carboxylic acid, saturated monocarboxylic acid and dicarboxylic acid. Is preferably 1000 g / eq, more preferably 500 g / eq, and particularly preferably 400 g / eq. On the other hand, the lower limit is preferably 100 g / eq, particularly preferably 200 g / eq, from the viewpoint of heat resistance and mechanical strength.

  Examples of the epoxy resin having two or more epoxy groups in one molecule include biphenyl aralkyl type epoxy resins, phenyl aralkyl type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, phenol aralkyl type epoxy resins, and dicyclopentadiene. Type epoxy resin, rubber modified epoxy resin such as silicone modified epoxy resin, ε-caprolactone modified epoxy resin, phenol novolac type epoxy resin such as bisphenol A type, bisphenol F type and bisphenol AD type, cresol novolac such as о-cresol novolak type Type epoxy resin, cycloaliphatic polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy resin, glycidylamine type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol-modified epoxy resin Examples include borak-type epoxy resins, polyfunctional modified novolak-type epoxy resins, condensate-type epoxy resins of phenols and aromatic aldehydes having a phenolic hydroxyl group, epoxy resins containing a fluorene skeleton, and epoxy resins incorporating an adamantane skeleton. be able to. Moreover, what introduce | transduced halogen atoms, such as Br and Cl, to these resin can also be used.

  Among these, from the viewpoint of the photosensitivity of the cured product of the photosensitive resin composition, elongation characteristics, and insulation reliability, biphenyl aralkyl epoxy resin, dicyclopentadiene epoxy resin, naphthalene epoxy resin, phenol aralkyl epoxy resin In view of excellent elongation characteristics, biphenyl aralkyl type epoxy resins, for example, the following general formula (2)

(In the formula, R ¹ represents a hydrogen atom, or a linear or branched alkyl group or aryl group having 1 to 8 carbon atoms, l is an integer of 1 to 3, and n is an integer of 1 to 10. The biphenyl aralkyl type epoxy resin and the phenol aralkyl type epoxy resin represented by.

Commercially available epoxy resins having two or more epoxy groups in one molecule include, for example, NC-3000 (Nippon Kayaku Co., Ltd., biphenylaralkyl in which R ^{1 in the} general formula (2) is a hydrogen atom. Type epoxy resin), HP-7200H (DIC Corporation, dicyclopentadiene type epoxy resin), NC-7000 and NC-7300 (Nippon Kayaku Co., Ltd., naphthalene type epoxy resin), NC-2000 (Nippon Kayaku Co., Ltd.) And phenol aralkyl type epoxy resins). The above-mentioned epoxy resin having two or more epoxy groups in one molecule may be used alone or in combination of two or more.

b) Saturated monocarboxylic acid having 5 to 17 carbon atoms The saturated monocarboxylic acid having 5 to 17 carbon atoms is, for example, a saturated monocarboxylic acid having a hydrocarbon group and having 5 to 17 carbon atoms. . The saturated monocarboxylic acid having 5 to 17 carbon atoms includes monobasic acids and fatty acids having 5 to 17 carbon atoms.

  The saturated monocarboxylic acid having 5 to 17 carbon atoms reacts with the epoxy group of an epoxy resin having two or more epoxy groups in one molecule, and the transparency derived from the saturated monocarboxylic acid in the resin, A medium chain to long chain hydrocarbon structure excellent in flexibility and insulation reliability is introduced. Accordingly, the cured coating film of the photosensitive resin composition has an excellent line shape in which undercut is prevented by imparting excellent transparency to the photosensitive resin composition, and further, the photosensitive resin composition The cured film of the product can obtain excellent elongation characteristics and insulation reliability. Moreover, the touch-drying property which was excellent in the photosensitive resin composition is provided by introduce | transducing the medium chain-long chain hydrocarbon structure derived from the said saturated monocarboxylic acid.

  Examples of saturated monocarboxylic acids having 5 to 17 carbon atoms include saturated monocarboxylic acids having a cyclic aliphatic hydrocarbon group, saturated monocarboxylic acids having a linear aliphatic hydrocarbon group, and branched chain fatty acids. Any saturated monocarboxylic acid having a group hydrocarbon group can be used. Of these, cohesive force, which is considered to be derived from the hydrophobic bond of the linear saturated aliphatic chain, occurs not only in the coating film after drying, but the coating film after preliminary drying has further excellent touch drying properties. In addition, by having a linear saturated aliphatic chain structure with more flexibility, the cured coating film has a better elongation characteristic and has a good balance between transparency and elongation characteristics. Saturated monocarboxylic acids having an aliphatic hydrocarbon group are preferred.

  Further, the saturated monocarboxylic acid is not particularly limited as long as it has a carbon number in the range of 5 to 17, but a carbon number of 5 to 12 is preferable from the viewpoint of improving the balance between transparency and elongation characteristics.

  Examples of the saturated monocarboxylic acid having 5 to 17 carbon atoms include pentanoic acid (C5), hexanoic acid (C6), heptanoic acid (C7), octanoic acid (C8), nonanoic acid (C9), decanoic acid ( C10), dodecanoic acid (C12), tetradecanoic acid (C14), hexadecanoic acid (C16), heptadecanoic acid (C17) and the like. These may be used alone or in combination of two or more.

  The ratio (charge ratio) of the saturated monocarboxylic acid having 5 to 17 carbon atoms in the carboxyl group-containing photosensitive resin (solid content) is not particularly limited, but the lower limit value is the elongation characteristic and the insulation reliability. 5.0 mass% is preferable from the point which improves more, and 8.0 mass% is especially preferable from the point which improves an elongation characteristic further. On the other hand, the upper limit is to ensure the introduction amount of the polybasic acid and / or polybasic acid anhydride while ensuring the photosensitivity by ensuring the introduction amount of the ethylenically unsaturated group-containing carboxylic acid. 20 mass% is preferable from the point which acquires developability reliably, and 18 mass% is especially preferable.

c) Dicarboxylic acid A dicarboxylic acid reacts with an epoxy group of an epoxy resin having two or more epoxy groups in one molecule to introduce a hydrocarbon structure of the dicarboxylic acid into the epoxy resin, and different epoxy of the above epoxy resin. By bonding the groups to each other via a dicarboxylic acid, the relatively rigid skeleton of the epoxy resin can be configured to be crosslinked by a covalent bond in a flexible hydrocarbon structure derived from a dicarboxylic acid. The epoxy resin is imparted with a structure excellent in elongation characteristics, transparency and dryness to the touch of the cured coating film. Further, by using a saturated monocarboxylic acid and a dicarboxylic acid in combination, a relatively low molecular weight epoxy resin can be adjusted to an appropriate molecular weight while having flexibility. Therefore, it can be set as the photosensitive resin composition used as the cured coating film excellent in the dryness of the touch after drying, maintaining a softness | flexibility and alkali developability.

  Examples of the dicarboxylic acid include a saturated dicarboxylic acid having an acyclic saturated aliphatic hydrocarbon group, an unsaturated dicarboxylic acid having an acyclic unsaturated aliphatic hydrocarbon group, and a saturated having a cyclic saturated aliphatic hydrocarbon group. Dicarboxylic acid and unsaturated dicarboxylic acid having a cyclic unsaturated aliphatic hydrocarbon group are preferred. The saturated dicarboxylic acid having an acyclic saturated aliphatic hydrocarbon group includes a linear aliphatic hydrocarbon group or a branched aliphatic hydrocarbon group having two or less side chains having 2 or less carbon atoms. Particularly preferred are saturated dicarboxylic acids having The unsaturated dicarboxylic acid having an acyclic unsaturated aliphatic hydrocarbon group includes a linear aliphatic hydrocarbon group or a branched aliphatic hydrocarbon group having 2 or less side chains having 2 or less carbon atoms. Unsaturated dicarboxylic acids having are particularly preferred.

  From the above, the dicarboxylic acid includes a saturated fatty acid that is a dibasic acid and an unsaturated fatty acid that is a dibasic acid.

  The carbon number of the dicarboxylic acid is not particularly limited, but in the case of a dicarboxylic acid having an acyclic aliphatic hydrocarbon group, the lower limit is preferably 5 carbon atoms, particularly 6 carbon atoms from the viewpoint of reliably obtaining elongation characteristics. preferable. On the other hand, the upper limit of the carbon number of the dicarboxylic acid having an acyclic aliphatic hydrocarbon group is an excellent line shape in which the transparency of the photosensitive resin composition is reliably improved and undercut is surely prevented. From the point of improving the touch drying property of the photosensitive resin composition with certainty, a carbon number of 20 is preferable, and the transparency of the photosensitive resin composition is further improved. From the point which can obtain the cured coating film which has the outstanding line shape, and the touch-drying property of the photosensitive resin composition further improves, C12 is more preferable and C10 is especially preferable. In the dicarboxylic acid having a cycloaliphatic hydrocarbon group, the lower limit is preferably 6 carbon atoms, particularly preferably 7 carbon atoms, from the viewpoint of reliably obtaining elongation characteristics. On the other hand, the upper limit of the carbon number of the dicarboxylic acid having a cycloaliphatic hydrocarbon group is an excellent line shape in which the transparency of the photosensitive resin composition is reliably improved and undercut is surely prevented. From the point which can obtain the cured coating film which has and the touch-drying property of the photosensitive resin composition improves reliably, carbon number 20 is preferable, and transparency of the photosensitive resin composition further improves, and it is more excellent. In view of the fact that a cured coating film having a line shape can be obtained and the touch-drying property of the photosensitive resin composition is further improved, carbon number 12 is more preferable, and carbon number 10 is particularly preferable.

The dicarboxylic acid is, for example, the following general formula (3)
^HOOC-R 3 -COOH (3)
(In the formula, R ³ represents an acyclic saturated aliphatic hydrocarbon group having ^{3 to} 18 carbon atoms, an acyclic unsaturated aliphatic hydrocarbon group having 3 to 18 carbon atoms, or a cyclic saturated aliphatic hydrocarbon group. Or a dicarboxylic acid compound represented by a cyclic unsaturated aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having 4 to 18 carbon atoms having one cyclic aliphatic hydrocarbon group). Is preferred.

  As the compound represented by the general formula (3), dicarboxylic acids having an acyclic aliphatic hydrocarbon group include, for example, pentanedioic acid (C5), adipic acid (C6), suberic acid (C8), and sebacic acid. Dicarboxylic acids such as (C10), dodecanedioic acid (C12), tetradecanedioic acid (C14), hexadecanedioic acid (C16), ethyloctadecanedioic acid (C20), eicosanedioic acid (C20), eicosadienedioic acid (C20) Is mentioned. Examples of the dicarboxylic acid having a cyclic aliphatic hydrocarbon group include dicarboxylic acids such as cyclobutane dicarboxylic acid (C6), cyclopentane dicarboxylic acid (C7), and cyclohexane dicarboxylic acid (C8). These may be used alone or in combination of two or more.

  The ratio (preparation ratio) of dicarboxylic acid in the carboxyl group-containing photosensitive resin (solid content) is not particularly limited, but the lower limit is 2.0% by mass from the viewpoint of further improving the elongation characteristics and the insulation reliability. Is preferable, and 3.0% by mass is particularly preferable from the viewpoint of further improving the elongation characteristics. On the other hand, the upper limit is to ensure the introduction amount of the polybasic acid and / or polybasic acid anhydride while ensuring the photosensitivity by ensuring the introduction amount of the ethylenically unsaturated group-containing carboxylic acid. 15 mass% is preferable from the point which acquires developability reliably, and 10 mass% is especially preferable.

  The reaction method of an epoxy resin having two or more epoxy groups in one molecule and at least one saturated monocarboxylic acid having 5 to 17 carbon atoms and a dicarboxylic acid may be a known method. An example is a reaction method in which the resin and the carboxylic acid are heated in a suitable diluent.

d) Ethylenically unsaturated group-containing carboxylic acid Ethylenically unsaturated group-containing carboxylic acid reacts with an epoxy group of an epoxy resin having two or more epoxy groups in one molecule, and the epoxy resin is reacted with a photopolymerization initiator. A photocurable group is introduced that can be polymerized by the generated free radicals. The ethylenically unsaturated group-containing carboxylic acid is not particularly limited as long as it imparts photocurability to the epoxy resin. For example, acrylic acid, methacrylic acid, β-acryloxypropionic acid, ω-carboxy-polycaprolactone -Carboxylic acid which can introduce | transduce an acryloyl group or a methacryloyl group into an epoxy resin, such as (meth) acrylic acid, crotonic acid, cinnamic acid. Among these, acrylic acid and methacrylic acid (hereinafter sometimes referred to as (meth) acrylic acid) are preferable, and acrylic acid is particularly preferable. These may be used alone or in combination of two or more.

  Although the ratio (preparation ratio) of the ethylenically unsaturated group-containing carboxylic acid in the carboxyl group-containing photosensitive resin (solid content) is not particularly limited, the lower limit is 2.0 mass from the viewpoint of further improving the sensitivity. % Is preferable, and 3.0% by mass is particularly preferable. On the other hand, the upper limit value is to maintain the introduction amount of saturated monocarboxylic acid and dicarboxylic acid having 5 to 17 carbon atoms to further improve the elongation characteristics and insulation reliability. 10% by mass is preferable, and 8.0% by mass is particularly preferable from the viewpoint of ensuring the alkali developability by maintaining the amount of basic acid anhydride introduced.

  The reaction method of the epoxy resin having two or more epoxy groups in one molecule and the ethylenically unsaturated group-containing carboxylic acid is not particularly limited. For example, the epoxy resin and the ethylenically unsaturated group-containing carboxylic acid are appropriately used. A reaction method of heating in a diluent is mentioned.

d) Polybasic acid, polybasic acid anhydride Polybasic acid, polybasic acid anhydride is a hydroxyl group produced by the reaction of the epoxy resin with a saturated monocarboxylic acid or dicarboxylic acid having 5 to 17 carbon atoms. A free carboxyl group is introduced into the epoxy resin by reacting with a hydroxyl group produced by a reaction with an ethylenically unsaturated group-containing carboxylic acid. Alkali developability is imparted by introducing a carboxyl group into the photosensitive resin. The polybasic acid and polybasic acid anhydride to be used are not particularly limited, and either saturated or unsaturated can be used. Examples of the polybasic acid include dicarboxylic acids, tricarboxylic acids, and carboxylic acids having 4 or more carboxyl groups. 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 thereof include phthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, trimellitic acid derivatives, pyromellitic acid and diglycolic acid. Examples of the polybasic acid anhydride include anhydrides of the above polybasic acid.

Of the polybasic acid and the polybasic acid anhydride, the polybasic acid anhydride is preferable from the viewpoint of the reaction efficiency with the hydroxyl group generated in the epoxy resin, that is, the ease of introduction of the free carboxylic acid, and the polybasic acid anhydride. In terms of alkali developability, the following general formula (1)
(In the formula, R ² represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, an aryl group, a carboxyl group, or a hydroxyl group, and m is an integer of 1 to 3). The compound represented by these is preferable.

  The compound represented by the general formula (1) includes a hydroxyl group formed by a reaction of a saturated monocarboxylic acid, dicarboxylic acid or carboxylic acid having an ethylenically unsaturated group having 5 to 17 carbon atoms with an epoxy group, and the above compound. The acid anhydride group reacts and is introduced into the resin skeleton by an ester bond. At this time, the compound represented by the general formula (1) can introduce two carboxyl groups into the resin per molecule. Therefore, while introducing many saturated monocarboxylic acid and dicarboxylic acid components into the resin, it is possible to introduce into the resin the amount of carboxyl groups necessary to efficiently obtain alkali solubility with a small number of hydroxyl groups.

  Therefore, while introducing many saturated monocarboxylic acid and dicarboxylic acid components into the resin, it is possible to introduce into the resin the amount of carboxyl groups necessary to efficiently obtain alkali solubility with a small number of hydroxyl groups. Thereby, the elongation characteristic and insulation reliability of the cured coating film by introduction of saturated monocarboxylic acid and dicarboxylic acid components, and alkali developability after preliminary drying can be achieved at a high level. In particular, the photosensitive resin composition containing the carboxyl group-containing photosensitive resin into which the compound represented by the general formula (1) is introduced while designing to the same carboxylic acid amount is other than the compound represented by the general formula (1). Compared with a carboxyl group-containing photosensitive resin into which a polybasic acid or anhydride thereof is introduced, alkali development can be performed in a shorter time. In addition, these compounds may be used independently and may mix and use 2 or more types in order to adjust alkali developability moderately.

  The ratio (preparation ratio) of the polybasic acid and / or polybasic acid anhydride in the carboxyl group-containing photosensitive resin (solid content) is not particularly limited, but the lower limit value is to obtain good alkali developability. To 7.0% by mass is preferable, and 9.0% by mass is particularly preferable. On the other hand, the upper limit is preferably 20% by mass, particularly preferably 16% by mass, from the viewpoint of reliably preventing a decrease in insulation reliability.

  The method of reacting a polybasic acid and / or polybasic acid anhydride with the unsaturated carboxylated epoxy resin that is the reaction product of the components a) to d) is not particularly limited. The reaction method of heating a polybasic acid and / or a polybasic acid anhydride in a suitable diluent, and adding a catalyst as needed is mentioned.

  The solid content acid value of the carboxyl group-containing photosensitive resin obtained by reacting a polybasic acid and / or polybasic acid anhydride with an unsaturated carboxylic acid epoxy resin, which is a reaction product of components a) to d), is Although not particularly limited, 30 to 80 mgKOH / g is preferable, and 40 to 70 mgKOH / g is particularly preferable from the viewpoint of a balance between good alkali developability and prevention of deterioration in insulation reliability.

  Although the mass average molecular weight of the said carboxyl group-containing photosensitive resin is not specifically limited, 3000 is preferable and 5000 is especially preferable from the point which prevents the toughness of a hardened | cured material and the touch dryness fall. On the other hand, the upper limit is preferably 50000 and particularly preferably 30000 from the viewpoint of preventing a decrease in alkali developability.

(B) Photopolymerization initiator The photopolymerization initiator is not particularly limited as long as it is generally used. For example, 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-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -Butanone-1, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, P -Dimethylaminobenzoic acid ethyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphite Oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide, 1,2-octanedione, 1- [ 4- (phenylthio)-, 2- (O-benzoyloxime)], 2-propanedione-2-O-benzoyloxime, 1-phenyl-1,2-propanedione-2-O-benzoyloxime, ethanone, 1 -[9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) and the like. These may be used alone or in combination of two or more.

  Since the photosensitive resin composition of the present invention has excellent transparency, the content of the photopolymerization initiator can be reduced as compared with the prior art, and as a result, gas generation from the photopolymerization initiator during photocuring can be prevented. An excellent coating film appearance can be obtained.

  Although content of a photoinitiator is not specifically limited, 5-30 mass parts is preferable with respect to 100 mass parts of (A) carboxyl group-containing photosensitive resin, and 10-25 mass parts is especially preferable.

(C) (Meth) acrylate monomer The (meth) acrylate monomer is a photopolymerizable monomer, and is photocured by irradiation with active energy rays such as ultraviolet rays, thereby sufficiently photocuring the photosensitive resin composition. It is used to obtain a cured product having acid resistance, heat resistance, alkali resistance and the like. Thus, the (meth) acrylate monomer functions as a reactive diluent.

  Examples of (meth) acrylate monomers include 2-hydroxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol di (meth) acrylate, and 2-hydroxy-3. -Phenoxypropyl (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neo Pentyl glycol adipate di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) Acrylate, ethylene oxide modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol Tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol Hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, urethane (meth) acrylate Rate monomer. These may be used alone or in combination of two or more.

  Although content of a (meth) acrylate monomer is not specifically limited, 5-30 mass parts is preferable with respect to 100 mass parts of (A) carboxyl group-containing photosensitive resin, and 10-25 mass parts is especially preferable.

(D) Epoxy compound The epoxy compound is for obtaining a cured product such as a cured coating film having sufficient mechanical strength by increasing the crosslinking density of the cured product. Examples of the epoxy compound include an epoxy resin. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin (for example, biphenyl novolak type epoxy resin, phenol novolak 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 cycloaliphatic oxide group, tricyclodecane oxide group, cyclopentene oxide group, etc. Having triazine ring such as epoxy resin, tris (2,3-epoxypropyl) isocyanurate, triglycidyltris (2-hydroxyethyl) isocyanurate Liglycidyl isocyanurate, dicyclopentadiene type epoxy resin, adamantane type epoxy resin, phenol aralkyl type epoxy resin, phenol modified xylene resin type epoxy resin, glycidyl ester type epoxy resin (for example, diglycidyl phthalate, dihydrohexaphthalate) Glycidyl ester, isophthalic acid diglycidyl ester, dimer acid diglycidyl ester, etc.). These compounds may be used alone or in combination of two or more.

  Although the compounding quantity of an epoxy compound is not specifically limited, 10-150 mass parts is preferable with respect to 100 mass parts of (A) carboxyl group-containing photosensitive resin, and 20-100 mass parts is especially preferable.

  Moreover, you may mix | blend a coloring agent, a non-reactive diluent, an additive, an antifoamer, etc. suitably other than the said (A)-(D) component as needed.

  The colorant is not particularly limited, such as a pigment or a dye, and any of a white colorant, a blue colorant, a yellow colorant, a black colorant, and the like can be used. Examples of the colorant include inorganic colorants such as titanium oxide, which is a white colorant, and carbon black, which is a black colorant, and organic colorants such as phthalocyanine and anthraquinone, such as phthalocyanine green and phthalocyanine blue. Can be mentioned.

  The non-reactive diluent is for adjusting the viscosity and drying property of the photosensitive resin composition. Examples of non-reactive diluents include organic solvents. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexane, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, isopropanol and cyclohexanol, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, Petroleum solvents such as petroleum ether and petroleum naphtha, cellosolves such as cellosolve and butylcellosolve, carbitols such as carbitol and butylcarbitol, ethyl acetate, butyl acetate, cellosolve acetate, butylcellosolve acetate, carbitol acetate and butyl carbitol Examples thereof include esters such as acetate and diethylene glycol monoethyl ether acetate.

  Examples of the additive include curing catalysts such as dicyandiamide (DICY) and its derivatives, melamine and its derivatives, coupling agents such as silane, titanate, and alumina, acetylacetone such as acetylacetonate Zn and acetylacetonate Cr. Metal salts, enamines, tin octylates, quaternary sulfonium salts, imidazoles such as triphenylphosphine, 2-mercaptobenzimidazole, imidazolium salts, thermosetting accelerators such as triethanolamine borate, polycarboxylic acid amides, etc. And thixotropic agents. In addition, examples of the antifoaming agent include silicone, hydrocarbon, and acrylic.

  The manufacturing method of the above-described photosensitive resin composition of the present invention is not limited to a specific method. For example, the above-described components may be mixed and dispersed with a three roll at room temperature after being blended at a predetermined ratio. it can. Moreover, you may pre-mix with a stirrer before the said mixing dispersion | distribution as needed.

  Next, the example of the usage method of the photosensitive resin composition of this invention is demonstrated. Here, first, a method for forming a solder resist film by coating the photosensitive resin composition of the present invention on a flexible wiring board having a circuit pattern formed by etching a copper foil will be described as an example.

  Screen printing, bar coater, spray coating, applicator, blade coater, knife coater, roll coater on the flexible wiring board having a circuit pattern formed by etching copper foil on the photosensitive resin composition produced as described above. The film is applied to a desired thickness using a known method such as a gravure coater. After coating, if necessary, preliminary drying is performed by heating at a temperature of about 60 to 80 ° C. for about 15 to 60 minutes to volatilize the solvent in the photosensitive resin composition, and the solvent is volatilized from the photosensitive resin composition. To make the surface of the coating film tack-free. On the applied photosensitive resin composition, a negative film having a light-transmitting pattern other than the land of the circuit pattern is brought into close contact, and ultraviolet rays (for example, in a wavelength range of 300 to 400 nm) are irradiated from above. 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 used include 0.5 to 5% by mass of an aqueous sodium carbonate solution. Next, the target solder resist film can be formed on the flexible wiring board by performing post-cure for 20 to 80 minutes with a hot air circulation dryer at 130 to 170 ° C.

  Next, an example of a method of forming a solder resist film on a flexible wiring board having a circuit pattern formed by etching a copper foil using a dry film coated with the photosensitive resin composition of the present invention will be described. To do.

  The dry film includes a support film (for example, a thermoplastic film such as a polyethylene terephthalate film and a polyester film), a solder resist layer coated on the support film, and a cover film (for example, a polyethylene film) that protects the solder resist layer. , Polypropylene film). After coating the photosensitive resin composition on the support film by a known method such as a roller coating method, the coating film is dried to form a solder resist layer on the support film. Then, a dry film can be produced by laminating a cover film on the formed solder resist layer. A solder resist film is formed on the flexible wiring board by bonding the solder resist layer and the flexible wiring board while peeling the cover film of the dry film. Thereafter, in the same manner as described above, a solder resist film having a target circuit pattern can be formed on the flexible wiring board by performing the steps of exposure, development, and curing.

  An electronic circuit unit is formed by soldering an electronic component to the flexible wiring board coated with the cured coating film thus obtained by a jet soldering method, a reflow soldering method, or the like.

  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.

Photosensitive resin A-1
106.1 g of NC-3000 (epoxy group: 0.383 mol, Nippon Kayaku Co., Ltd.) and dodecanoic acid 24. in a 300 ml four-necked separable flask equipped with a stirring blade, thermometer, reflux tube and nitrogen introduction tube. 6 g (carboxylic acid: 0.123 mol, Kishida Chemical Co., Ltd.), adipic acid 8.4 g (carboxylic acid: 0.115 mol, Kishida Chemical Co., Ltd.), diethylene glycol monoethyl ether acetate 66.1 g (Sanyo Chemicals Co., Ltd.) In addition, the mixture was stirred for 30 minutes at 110 ° C. in a nitrogen / oxygen mixed gas atmosphere, and mixed and dissolved. Subsequently, after raising the temperature of the reaction solution to 115 ° C., 0.3 g of 4-methoxyphenol (Kishida Chemical Co., Ltd.), 10.4 g of acrylic acid (carboxylic acid: 0.145 mol, Osaka Organic Chemical Industry Co., Ltd.) ), 0.9 g of triphenylphosphine (Kishida Chemical Co., Ltd.) was added. It stirred at 115 degreeC for 8 hours, the acid value measurement was performed, and it was confirmed that carboxylic acid has lose | disappeared completely. Then, 24.8 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (H-TMAn-S) (carboxylic anhydride: 0.125 mol, Mitsubishi Gas Chemical Co., Ltd.) After adding 16.5 g of diethyl diglycol (Nippon Emulsifier Co., Ltd.) and stirring at 100 ° C. for 2 hours, the completion of the reaction was confirmed by FT-IR (infrared spectrophotometer), and the photosensitivity blended in Example 1 258.0g of resin A-1 was obtained. The mass average molecular weight (Mw) was 9100.

Photosensitive resin A-2
In the same manner as the photosensitive resin A-1, 106.1 g of NC-3000, 24.6 g of dodecanoic acid, 9.9 g of 1,4-cyclohexanedicarboxylic acid (carboxylic acid: 0.115 mol, Tokyo Chemical Industry Co., Ltd.) Diethylene glycol monoethyl ether acetate 66.2 g, 4-methoxyphenol 0.3 g, acrylic acid 10.4 g, triphenylphosphine 0.8 g, H-TMAn-S 24.8 g, diethyl diglycol 16.5 g were reacted. 258.5g of photosensitive resin A-1 mix | blended in Example 2 was obtained. Mw was 8400.

Photosensitive resin A-3
In the same manner as the photosensitive resin A-1, 106.1 g of NC-3000, 16.0 g of heptanoic acid (carboxylic acid: 0.123 mol, Kishida Chemical Co., Ltd.), 11.6 g of sebacic acid (carboxylic acid: 0.115 mol) Kishida Chemical Co., Ltd.), 63.6 g of diethylene glycol monoethyl ether acetate, 0.3 g of 4-methoxyphenol, 10.4 g of acrylic acid, 0.8 g of triphenylphosphine, 23.8 g of H-TMAn-S (carboxylic acid anhydride: 0.120 mol) and 15.9 g of diethyldiglycol were reacted to obtain 248.4 g of photosensitive resin A-3 to be blended in Example 3. Mw was 9700.

Photosensitive resin A-4
Similarly to the photosensitive resin A-1, 106.1 g of NC-3000, 19.5 g of heptanoic acid (carboxylic acid: 0.150 mol), 19.7 g of 8-ethyloctadecanedioic acid (carboxylic acid: 0.115 mol, Okamura Oil Co., Ltd.), diethylene glycol monoethyl ether acetate 69.1 g, 4-methoxyphenol 0.2 g, acrylic acid 10.4 g, triphenylphosphine 0.7 g, H-TMAn-S 27.1 g (carboxylic anhydride: 0) .137 mol) and 17.3 g of diethyl diglycol were reacted to obtain 270.1 g of photosensitive resin A-4 to be blended in Example 4. Mw was 10,000.

Photosensitive resin A-5
Similarly to the photosensitive resin A-1, 104.7 g (epoxy group: 0.378 mol) of NC-3000, 32.7 g of behenic acid (carboxylic acid: 0.096 mol, NOF Corporation), stearic acid 6. 9 g (carboxylic acid: 0.024 mol, NOF Corporation), 8-ethyloctadecanedioic acid 19.5 g (carboxylic acid: 0.114 mol, Okamura Oil Co., Ltd.), diethylene glycol monoethyl ether acetate 76.8 g, 4-methoxy Comparative Example 1 was prepared by reacting 0.3 g of phenol, 10.2 g of acrylic acid, 0.9 g of triphenylphosphine, 28.8 g of H-TMAn-S (carboxylic anhydride: 0.145 mol), and 19.2 g of diethyl diglycol. 300.0g of photosensitive resin A-5 mix | blended in was obtained. Mw was 10500.

Photosensitive resin A-6
In the same manner as the photosensitive resin A-1, 106.1 g of NC-3000, 59.1 g of diethylene glycol monoethyl ether acetate, 0.2 g of 4-methoxyphenol, 27.6 g of acrylic acid, 0.7 g of triphenylphosphine, H -TMAn-S22.3g (carboxylic acid anhydride: 0.113mol) and diethyl diglycol 14.8g were made to react, and 230.7g of photosensitive resin A-6 mix | blended with the comparative example 2 was obtained. Mw was 2000.

Photosensitive resin A-7
In the same manner as the photosensitive resin A-1, 106.1 g of NC-3000, 8.4 g of adipic acid, 59.1 g of diethylene glycol monoethyl ether acetate, 0.2 g of 4-methoxyphenol, 19.3 g of acrylic acid, triphenyl Phosphine 0.7g, H-TMAn-S22.3g, and diethyl diglycol 14.8g were reacted, and 230.9g of photosensitive resin A-7 mix | blended with the comparative example 3 was obtained. Mw was 7000.

Photosensitive resin A-8
In the same manner as the photosensitive resin A-1, 106.1 g of NC-3000, 46.6 g of dodecanoic acid (carboxylic acid: 0.233 mol), 72.1 g of diethylene glycol monoethyl ether acetate, 0.2 g of 4-methoxyphenol, Acrylic acid 10.8 g (carboxylic acid: 0.150 mol), triphenylphosphine 0.7 g, H-TMAn-S 27.1 g (carboxylic anhydride: 0.137 mol), diethyl diglycol 18.0 g were reacted, 281.5g of photosensitive resin A-8 mix | blended with the comparative example 4 was obtained. Mw was 4000.

Photosensitive resin A-9
The photosensitive resin A was used except that NC-7000 was replaced with 106.1 g (epoxy group: 0.383 mol), and NC-7000 was used with 88.8 g (epoxy group: 0.383 mol, Nippon Kayaku Co., Ltd.). In the same manner as in Example 1, 240.7 g of photosensitive resin A-9 blended in Example 5 was obtained. Mw was 10,000.

Photosensitive resin A-10
The photosensitive resin A was used except that NC-2000 was replaced with 96.1 g (epoxy group: 0.383 mol, Nippon Kayaku Co., Ltd.) instead of NC-3000 at 106.1 g (epoxy group: 0.383 mol). In the same manner as in Example 1, 243.1 g of photosensitive resin A-10 to be blended in Example 6 was obtained. Mw was 8000.

It shows in following Table 1 about the mass ratio of each component of photosensitive resin A-1 to A-10. The photosensitive resins A-1 to A-10 were dried at 150 ° C. for 2 hours, and the solid contents of the photosensitive resins A-1 to A-10 were determined from the mass ratios before and after drying. The solution acid value was measured by a phenolphthalein discoloration method based on alkali neutralization titration. The mass average molecular weight (Mw) was measured using a gel permeation chromatography (GPC) apparatus (Shimadzu Corporation) under the following conditions.
Column: TSKgel (Tosoh Corporation)
Detector: Differential refractive index detector Developing solvent: Tetrahydrofuran standard: Standard polystyrene Flow rate: 0.5 ml / min

Examples 1-6, Comparative Examples 1-4
Each component shown in the following Table 2 is blended at the blending ratio shown in the following Table 2, mixed and dispersed at room temperature using three rolls, and used in Examples 1 to 6 and Comparative Examples 1 to 4. A functional resin composition was prepared. In addition, the compounding quantity shown in following Table 2 represents a mass part.

Test piece preparation process The photosensitive resin composition prepared as mentioned above was applied as follows, and the test piece was produced.

A substrate for a flexible wiring board having a circuit pattern formed on a polyimide film (Toray DuPont Co., Ltd., Kapton 100H) is surface-treated with dilute sulfuric acid (3% by mass), and then each prepared photosensitive resin composition by screen printing. After coating, preliminary drying was performed at 80 ° C. for 20 minutes in a BOX furnace. After pre-drying, a negative film (photomask) having a light-transmitting pattern other than the circuit pattern land is brought into close contact with the coating film, and then ultraviolet rays are applied to the exposure device (Oak Manufacturing Co., Ltd., HMW-680GW). Exposure to 500 mJ / cm ² . Then, after developing with a 1% by weight sodium carbonate developer at 30 ° C., a cured coating film is formed on the substrate by post-curing at 150 ° C. for 60 minutes in a BOX furnace. Examples and Comparative Examples The test piece was obtained. The thickness of the cured coating film was 20 to 23 μm.

Evaluation items (1) Undercut (resolution)
A cured coating line was formed on the polyimide film using a photomask having a width of 100 μm. The line shape is observed with a metallographic microscope (magnification: 100 times) from the cut surface of the formed line, and the width (x) on the surface side of the line and the width (y) on the bottom side (deep side) are measured. The undercut value was measured from -y) / 2 and evaluated according to the following criteria.
○: 5 μm or less Δ: More than 5 μm and 15 μm or less ×: More than 15 μm

(2) Growth rate (%)
After the photosensitive resin composition prepared as described above is uniformly applied to a polyethylene terephthalate (PET) film so as to have a thickness of 50 μm ± 10 μm using a bar coater, the above steps from preliminary drying to post-cure are performed. Went to form a cured coating. Thereafter, the formed cured coating film was peeled off from the PET film and cut into a predetermined size, and the elongation was measured under the condition of a pulling speed of 5 mm / min using an autograph manufactured by Shimadzu Corporation. The evaluation was based on the following criteria.
◎: Over 60% ○: Over 45% over 60% △: Over 30% over 45% ×: 30% or less

(3) Dryness to touch The negative film was brought into contact with the coating film after the preliminary drying in the test piece preparation step, and the sticking property of the coating film to the negative film after exposure was evaluated. Evaluation was performed according to the following criteria.
○: No stickiness △: Trace of sticking remains on the coating film ×: After peeling off the negative film, the coating film adheres to the negative film

  The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 2 below.

  From Table 2, an epoxy resin having two or more epoxy groups in one molecule, a saturated monocarboxylic acid having 5 to 17 carbon atoms (in the examples, a saturated monocarboxylic acid having 7 or 12 carbon atoms) and a dicarboxylic acid An unsaturated carboxylic acid epoxy resin which is a reaction product of a carboxylic acid having an ethylenically unsaturated group (acrylic acid in the examples) and e) a polybasic acid and / or a polybasic acid anhydride (cyclohexane in the examples) -1,2,4-tricarboxylic acid-1,2-anhydride) added, carboxyl group-containing photosensitive resins (photosensitive resins A-1 to A-4, A-9 to A-10) In Examples 1 to 6 using the above, a transparent resin solution was obtained, and excellent touch-drying properties were provided. Furthermore, in Examples 1-6, the cured coating film which has the outstanding line shape by which the undercut was prevented, and was excellent in the elongation characteristic was able to be obtained. In particular, Examples 1-3, 5, and 6 in which the carbon number of the dicarboxylic acid introduced into the carboxyl group-containing photosensitive resin is 6 to 10 are further compared to Example 4 in which the carbon number is 20 as described above. An excellent line shape could be obtained, and the resolution was further improved. Moreover, Example 1 using the biphenyl aralkyl type epoxy resin and Example 6 using the phenol aralkyl type epoxy resin further improved the elongation as compared with Example 5 using the naphthalene type epoxy resin.

  On the other hand, in Comparative Example 1 in which a saturated monocarboxylic acid having 18 carbon atoms and a saturated carboxylic acid having 22 carbon atoms were introduced into the epoxy resin and no medium chain to long chain dicarboxylic acid was introduced, Transparency was lowered, and undercut was not prevented and resolution was not obtained. Further, in Comparative Example 1, it was not possible to obtain touch dryness. Further, Comparative Example 2 in which neither a medium chain to long chain saturated monocarboxylic acid nor a medium chain to long chain saturated carboxylic acid was introduced into the carboxyl group-containing photosensitive resin, the medium chain to long chain saturated monocarboxylic acid was added to the carboxyl group-containing photosensitive resin. Comparative Example 3 in which medium chain dicarboxylic acid having 6 carbon atoms was introduced without introducing carboxylic acid, and long chain saturated monocarboxylic acid having 12 carbon atoms without introducing medium to long chain dicarboxylic acid into the carboxyl group-containing photosensitive resin In Comparative Example 4 in which an acid was introduced, the elongation characteristics were not improved and flexibility was not obtained.

  The photosensitive resin composition of the present invention has an excellent line shape in which undercut is prevented without impairing basic characteristics such as dryness to touch and can provide a cured coating film having excellent elongation characteristics. Therefore, for example, the utility value is high in the field of a protective film of a printed wiring board (for example, a flexible wiring board or a rigid wiring board) on which electronic components are mounted with high density.

Claims (10)

  (A) a) an epoxy resin having two or more epoxy groups in one molecule, b) at least one saturated monocarboxylic acid having 5 to 17 carbon atoms, c) dicarboxylic acid and d) ethylenic unsaturation A carboxyl group-containing photosensitive resin obtained by adding e) a polybasic acid and / or a polybasic acid anhydride to an unsaturated carboxylic acid epoxy resin which is a reaction product with a group-containing carboxylic acid, and (B) A photosensitive resin composition comprising a photopolymerization initiator.   2. The photosensitive resin composition according to claim 1, wherein the b) at least one saturated monocarboxylic acid having 5 to 17 carbon atoms is linear.   The photosensitive resin composition according to claim 1 or 2, wherein the c) dicarboxylic acid contains at least one dicarboxylic acid having 6 to 20 carbon atoms.   The photosensitive resin composition according to claim 1 or 2, wherein the c) dicarboxylic acid contains at least one dicarboxylic acid having 6 to 10 carbon atoms. The e) polybasic acid and / or polybasic acid anhydride is a polybasic acid anhydride, and the polybasic acid anhydride is represented by the following general formula (1):
(In the formula, R ² represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, an aryl group, a carboxyl group, or a hydroxyl group, and m is an integer of 1 to 3). The photosensitive resin composition according to claim 1, wherein the photosensitive resin composition is a compound represented by the formula:   Furthermore, (C) (meth) acrylate monomer is contained, The photosensitive resin composition of any one of the Claims 1 thru | or 5 characterized by the above-mentioned.   Furthermore, (D) an epoxy compound is contained, The photosensitive resin composition of any one of the Claims 1 thru | or 6 characterized by the above-mentioned.   A dry film, wherein the photosensitive resin composition according to claim 1 is coated on a film.   A printed wiring board comprising a photocured film obtained by patterning a coating film formed by laminating the dry film according to claim 8 on a substrate.   A printed wiring board comprising a photocured film obtained by patterning a coating film formed by applying the photosensitive resin composition according to claim 1 onto a substrate.