JPWO2019160126A1 - Photosensitive resin composition, cured film, printed wiring board and its manufacturing method, and photosensitive resin composition manufacturing kit - Google Patents

Abstract

The photosensitive resin composition is a polymer having (A1) a carboxyl group and no ethylenically unsaturated group; (A2) a polymer having a carboxyl group and an ethylenically unsaturated group; (B) an ethylenically unsaturated polymer. It contains a compound having a group and no carboxyl group (C) a thermosetting resin; (D) a metal inactivating agent; (E) a photopolymerization initiator; and (F) a coloring agent. A cured film can be formed by irradiating the coating film of the photosensitive resin composition with active light and then heat-curing it by heating.

Description

The present invention relates to a photosensitive resin composition containing a colorant, a cured film obtained by curing the photosensitive resin composition, and a printed wiring board with a cured film provided with a cured film on the printed wiring board. Furthermore, the present invention relates to a kit for preparing a photosensitive resin composition.

Since a surface protective material for a flexible printed wiring board (FPC) is required to have high heat resistance, a cured film obtained by curing a resin composition by photocuring or thermosetting is used. Known methods for improving the heat resistance of the cured film include improving the crosslink density of the resin composition and increasing the amount of aromatic rings (for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2016-008267 Japanese Unexamined Patent Publication No. 2001-249450

Generally, the FPC is mounted inside the housing of the device and is not visible from the outside during normal use. Therefore, conventionally, the surface protection material of FPC has not been required from the viewpoint of designability. On the other hand, in recent years, there has been an increasing demand for uniformity and design of the visual appearance inside the device when the housing is removed for the purpose of replacing, adding, or maintaining parts. Along with this, there is an increasing demand for coloring materials such as black and red for the parts mounted in the housing of the device.

By adding a colorant such as a dye or a pigment to the resin composition constituting the surface protective material of FPC, a surface protective material colored in various colors can be obtained. However, the cured film (colored cured film) of the photosensitive resin composition to which the colorant is added may be inferior in heat resistance even if the composition other than the colorant is the same, as compared with the case where the colorant is not contained. is there.

In view of the above, an object of the present invention is to provide a photosensitive resin composition containing a colorant and having a cured film having excellent heat resistance.

The resin composition of the present invention comprises (A) a polymer having a carboxyl group, (B) a compound having at least one ethylenically unsaturated group in the molecule and having no carboxyl group, and (C) a thermosetting resin. , (D) Metal inactivating agent, (E) Photopolymerization initiator, and (F) Coloring agent. The component (A) includes (A1) a polymer having a carboxyl group and no ethylenically unsaturated group, and (A2) a polymer having a carboxyl group and having an ethylenically unsaturated group.

The acid value of each of the component (A1) and the component (A2) is preferably 5 to 200 mgKOH / g, and the weight average molecular weight is preferably 1,000 to 1,000,000. The component (A2) is preferably a polymer containing at least one carboxyl group and two or more (meth) acryloyl groups in one molecule. A preferred example of the component (A2) is an acid-modified epoxy (meth) obtained by adding a saturated or unsaturated polyvalent carboxylic acid anhydride to an ester obtained by reacting an epoxy resin with an unsaturated monocarboxylic acid. ) Acrylate can be mentioned.

Specific examples of the ethylenically unsaturated group in the component (A2) and the component (B) include a vinyl group and a (meth) acryloyl group. Both the component (A2) and the component (B) are preferably polyfunctional (meth) acrylic compounds having two or more (meth) acryloyl groups in one molecule.

As the component (B), a compound containing three or more (meth) acryloyl groups in one molecule may be used. From the viewpoint of increasing the crosslink density, the component (B) preferably contains a polyfunctional (meth) acrylate having a functional group equivalent of (meth) acryloyl group of 80 to 300. As the component (B), a polyfunctional (meth) acrylic compound containing three or more (meth) acryloyl groups in one molecule and having a functional group equivalent of (meth) acryloyl groups of 80 to 300 may be used. A polyfunctional (meth) acrylate having a functional group equivalent of (meth) acryloyl group of 80 to 300 may be used in combination with a polyfunctional (meth) acrylic oligomer. The combined use of a polyfunctional (meth) acrylic oligomer tends to improve the flexibility of the cured film.

As the component (C), a polyfunctional epoxy resin having two or more epoxy groups in one molecule is preferable, and a polyfunctional epoxy resin having a weight average molecular weight of 1500 or less is particularly preferable.

As the component (D), for example, a benzamide derivative having a phenolic hydroxyl group or a hydrazide derivative having a phenolic hydroxyl group is used.

As the component (E), a photoradical polymerization initiator having an absorption band at a wavelength of 405 nm is preferable. The extinction coefficient of the photoradical polymerization initiator at a wavelength of 405 nm ^{is preferably 20 [% -1} · cm ^-1 ] or more. Specific examples of the component (E) include oxime esters.

The photosensitive resin composition contains 100 parts by weight of the total contents of (A), (B) and (C), and the content of (A) (total of the contents of (A1) and (A2)). However, it is preferably 30 to 80 parts by weight. The content of (B) is preferably 5 to 30 parts by weight, and the content of (C) is preferably 10 to 40 parts by weight.

The above-mentioned photosensitive resin composition can also be provided in the form of a kit containing at least the first agent and the second agent individually. That is, the photosensitive resin composition preparation kit individually contains the first agent and the second agent. A photosensitive resin composition can be prepared by mixing the first agent and the second agent.

In a preferred embodiment, the first agent of the kit comprises component (A) and the second agent comprises component (D). By storing the component (A) and the component (D) without mixing, the stability of the solution tends to be improved. The first agent of the kit may contain the component (B) in addition to the components (A1) and (A2), and the second agent of the kit contains the component (E) in addition to the component (D). You may be. The second agent of the kit may contain the component (C).

A cured film can be obtained by photocuring and thermosetting the above photosensitive resin composition. For example, the above-mentioned photosensitive resin composition is applied to the surface of a printed wiring board to form a coating film, and at least a part of the surface of the coating film is irradiated with active light to perform photocuring, and it is necessary. A printed wiring board with a cured film can be formed by heat-curing the coating film after photo-curing after developing with alkali or the like accordingly. The printed wiring board may be a flexible printed wiring board using a flexible film base material such as a polyimide film.

The photosensitive resin composition of the present invention can realize high heat resistance even when a colored cured film is formed on the metal wiring of the printed wiring board.

The photosensitive resin composition of the present invention comprises (A) a carboxyl group-containing polymer, (B) a photocurable compound having an ethylenically unsaturated group, (C) a thermosetting resin, and (D) a metal inactivating agent. It contains (E) a photopolymerization initiator and (F) a colorant. The component (A) includes (A1) a polymer having a carboxyl group and no ethylenically unsaturated group, and (A2) a compound having a carboxyl group and having an ethylenically unsaturated group.

Since the component (A) has a carboxyl group, the photosensitive resin composition is alkali-soluble. In the photosensitive resin composition, the component (E) is activated by exposure (irradiation with active light), and the photoradical polymerization reaction of the components (A2) and (B) proceeds. Photocuring makes the resin composition insoluble in alkali. When the resin composition is heated, the component (C) is thermoset. During thermosetting, the carboxyl groups of the components (A1) and (A2) react with the component (C) to form a crosslinked structure. Since the component (A2) contributes to both the formation of a photocrosslinked network by photocuring and the formation of a thermosetting network by thermosetting, a cured film having high film strength and heat resistance can be formed. The component (A1) does not have photocurability and contributes only to the formation of a thermally crosslinked network. Therefore, the cured film can be made flexible.

When the photosensitive resin composition contains the component (D), inhibition of the curing reaction caused by the metal (ion) at the interface with the metal layer such as copper foil and deterioration of the cured film are suppressed. When the photosensitive resin composition contains the component (F), a cured film colored in a desired color such as black can be obtained.

Hereinafter, preferred forms of each component constituting the photosensitive resin composition will be described in order. Unless otherwise specified, each of the following components may be used alone or in combination of two or more. As used herein, "(meth) acrylic" means acrylic or methacrylic, and "(meth) acryloyl" means acryloyl or methacryloyl.

<(A) Carboxyl group-containing polymer>
The component (A) is a polymer having at least one carboxyl group in the molecule, and is a main component for forming a coating film of the resin composition. The component (A) is soluble in an organic solvent. Examples of the organic solvent in which the component (A) can be dissolved include sulfoxides, formamides, acetamides, pyrrolidones, phosphoramides, lactones, ethers, acetates and the like. The component (A) is preferably soluble in any of these organic solvents at a concentration of 5% by weight or more.

The weight average molecular weight of the component (A) in terms of polyethylene glycol is preferably 1,000 to 1,000,000, more preferably 2,000 to 200,000, further preferably 3,000 to 100,000, and 4,000. ~ 50,000 is particularly preferable. When the weight average molecular weight of the carboxyl group-containing compound is within the above range, a cured film having excellent heat resistance and flexibility can be easily obtained.

Since the photosensitive resin composition has a carboxyl group-containing polymer as the component (A), the photosensitive resin composition before curing is alkaline-soluble. The carboxyl group of the component (A) contained in the photosensitive resin composition may be a carboxylic acid anhydride obtained by dehydrating the two carboxyl groups.

The acid value of the component (A) is preferably 5 to 200 mgKOH / g, more preferably 10 to 150 mgKOH / g, and even more preferably 15 to 100 mgKOH / g. When the acid value of the component (A) is in the above range, the photosensitive resin composition before curing exhibits an appropriate alkali solubility. Further, when the acid value is in the above range, the heat resistance, insulation reliability and chemical resistance of the cured film can be improved, and flexibility can be imparted.

As described above, the component (A) includes (A1) a polymer having no ethylenically unsaturated group and (A2) a polymer having an ethylenically unsaturated group. The component (A1) contributes to the formation of the thermally crosslinked network and does not contribute to the formation of the photocrosslinked network. The component (A2) contributes to both the formation of the thermally crosslinked network and the formation of the photocrosslinked network.

<(A1) Carboxyl group-containing polymer having no ethylenically unsaturated group>
The component (A1) is a polymer containing a carboxyl group and no ethylenically unsaturated group. Specific examples of the component (A1) include a carboxyl group-containing (meth) acrylic polymer, a carboxyl group-containing vinyl polymer, an acid-modified polyurethane, an acid-modified polyester, an acid-modified polycarbonate, an acid-modified polyamide, an acid-modified polyimide, and an acid-modified polyurethane. Examples thereof include amide and acid-modified polyurethaneimide. From the viewpoint of the flexibility and chemical resistance of the cured film, a carboxyl group-containing (meth) acrylic copolymer, an acid-modified polyurethane, an acid-modified polyamide, and an acid-modified polyimide are preferable.

The component (A1) can be obtained by various known methods. The polymerization may be either solution polymerization or solvent-free polymerization, but solution polymerization is preferable in order to control the reaction. As the organic solvent for solution polymerization, a solvent capable of dissolving both the monomer component and the polymer after polymerization can be used without particular limitation. The amount of solvent in solution polymerization may be adjusted so that the solution concentration is 5 to 90% by weight, preferably 20 to 70% by weight.

The carboxyl group-containing (meth) acrylic polymer is a copolymer containing a (meth) acrylic acid ester and a compound having a carboxyl group and a polymerizable double bond in one molecule as a monomer component. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, crotonic acid, isocrotonic acid, myristolenic acid, palmitreic acid, oleic acid, ellagic acid, buxenoic acid, gadrain acid, eicosenoic acid, erucic acid, nervonic acid, and ω-carboxy. -Polycaprolactone mono (meth) acrylate, monohydroxyethyl phthalate (meth) acrylate, (meth) acrylic acid dimer, 2- (meth) acryloyoxypropyl hexahydrophthalic acid, 2- (meth) acryloyoxyethyl succinct Acids, maleic acid, fumaric acid, citraconic acid, mesaconic acid, atropic acid, cinnamic acid, linoleic acid, eikosazienoic acid, docosadienoic acid, linolenic acid, pinolenic acid, eleostearic acid, meadic acid, dihomo-Y-linolenic acid , Eikosatrienic acid, stearidonic acid, arachidonic acid, eikosatetraenoic acid, adrenoic acid, boseopentaenoic acid, eikosapentaenoic acid, osbondic acid, sardine acid, tetracosapentaenoic acid, docosahexaenoic acid, heric acid, 2,2 Examples thereof include 2-tris (meth) acryloyloxymethylsuccinic acid and 2-tris (meth) acryloyloxymethylethylphthalic acid. As the (meth) acrylic acid ester, a (meth) acrylic acid alkyl ester is preferable.

In addition to the carboxyl group-containing monomer and (meth) acrylic acid ester, the carboxyl group-containing (meth) acrylic polymer contains (meth) acrylamide such as diacetone (meth) acrylamide, acrylonitrile, and vinyl-n-butyl ether as copolymerization components. Etc., Esters of vinyl alcohol, styrene, vinyl toluene and the like may be contained. The carboxyl group-containing (meth) acrylic polymer can be obtained, for example, by radical polymerization of the above-mentioned monomer components. The radical polymerization may be thermal polymerization or photopolymerization. A polymerization initiator may be used for radical polymerization. The carboxyl group-containing (meth) acrylic polymer is preferably obtained by solution polymerization using an azo compound, an organic peroxide, a persulfate, hydrogen peroxide or the like as a thermal polymerization initiator.

The acid-modified polyurethane can be obtained, for example, by reacting a diol compound containing two hydroxyl groups and one carboxyl group with a diisocyanate compound.

The acid-modified polyester is obtained, for example, by reacting a diol compound containing two hydroxyl groups and one carboxyl group with a dicarboxylic acid.

The acid-modified polyamide is a compound having an amic acid structure, and is obtained, for example, by reacting a diamino compound with a tetracarboxylic dianhydride.

The acid-modified polyimide can be obtained, for example, by reacting a diisocyanate compound with a tetracarboxylic dianhydride. By adding tetracarboxylic dianhydride in excess of the equivalent of the diisocyanate compound, an imide compound having a carboxylic acid anhydride group at the terminal is obtained. By reacting an imide compound having a carboxylic acid anhydride group at the terminal with water and / or a primary alcohol such as methanol, ethanol, propanol or butanol, an imide compound having a carboxyl group at the terminal can be obtained.

Examples of the diol compound containing two hydroxyl groups and one carboxyl group include 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (2-hydroxyethyl) propionic acid, and 2,2-bis (3-). Hydroxymepropyl) propionic acid, 2,3-dihydroxy-2-methylpropionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,2-bis (2-hydroxyethyl) butanoic acid, 2,2-bis Alibo diols such as (3-hydroxypropyl) butanoic acid, 2,3-dihydroxybutanoic acid, 2,4-dihydroxy-3,3-dimethylbutanoic acid, and 2,3-dihydroxyhexadecanoic acid; 2,3- Fragrant diols such as dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, and 3,5-dihydroxybenzoic acid Can be mentioned. In particular, when an aliphatic diol is used, the photosensitive resin composition tends to have excellent photosensitivity.

The diisocyanate compound may be either an alicyclic diisocyanate compound or an aliphatic diisocyanate compound. The diisocyanate compound may be a reaction product of a compound having two or more functional groups capable of reacting with the isocyanate group of the diisocyanate compound, and may be, for example, a urethane compound having an isocyanate group at the terminal.

The tetracarboxylic dianhydride may be either an aromatic tetracarboxylic dianhydride or an aliphatic tetracarboxylic dianhydride, and the aromatic tetracarboxylic dianhydride having a carboxylic acid anhydride group directly bonded to the aromatic ring. An anhydride is preferred. Of these, aromatic tetracarboxylic dianhydrides are preferable, and those in which an anhydrous carboxyl group is directly bonded to an aromatic ring are preferable. The diamino compound may be either an aromatic diamine or an aliphatic diamine, and an aromatic diamine is preferable.

<(A2) Polymer having carboxyl group and ethylenically unsaturated group>
The component (A2) is a polymer having an ethylenically unsaturated group in addition to the carboxyl group. Ethylene unsaturated groups include (meth) acryloyl groups and vinyl groups. Since the component (A2) reacts with the component (C) during heat curing and with the component (B) during photocuring, the crosslink density of the cured film is increased, and heat resistance and chemical resistance are improved. Tends to improve.

As the component (A2), an acid-modified epoxy (meth) acrylate obtained by adding a saturated or unsaturated polyvalent carboxylic acid anhydride to an ester obtained by reacting an epoxy resin with an unsaturated monocarboxylic acid; Urethane (meth) acrylate, which is a polymer of a diol compound having an ethylenically unsaturated group and / or a carboxyl group and a diisocyanate compound; (meth) acrylic acid and (meth) having a carboxyl group and a polymerizable double bond. (Meta) acrylicization obtained by reacting a part of the carboxyl group of the side chain of the copolymer with acrylic ester or the like with the (meth) acrylic group such as glycidyl (meth) acrylate and the epoxy group of the compound having an epoxy group. Examples thereof include (meth) acrylate.

Examples of the saturated or unsaturated polybasic acid anhydride used in the synthesis of the epoxy (meth) acrylate include anhydrides such as phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, succinic acid, and trimellitic acid. Can be mentioned. Examples of the skeleton structure of the acid-modified epoxy (meth) acrylate (skeleton structure of the epoxy resin) include bisphenol A type, bisphenol E type, bisphenol F type, biphenyl type, cresol novolac type, and phenol novolac type. As the component (A2), an acid-modified epoxy (meth) acrylate in which a highly flexible structure such as a polyoxyalkylene or a polyurethane chain is introduced into the skeleton of the epoxy resin may be used. By using a polymer having a flexible skeletal structure such as a polyurethane chain as the component (A2), the flexibility of the cured film tends to be improved.

Examples of commercially available products of epoxy (meth) acrylate having a carboxyl group include KAYARAD ZFR series, ZAR series, ZCR series, CCR series, PCR series, and UXE series manufactured by Nippon Kayaku. Examples of commercially available urethane (meth) acrylates having a carboxyl group include the UX series manufactured by Nippon Kayaku. Examples of commercially available products of (meth) acrylicized (meth) acrylate include the cyclomer ACA series manufactured by Daicel Cytec.

The content of the component (A) (the total content of (A1) and (A2)) is preferably 10 to 80 parts by weight, more preferably 10 to 80 parts by weight, based on 100 parts by weight of the total solid content of the photosensitive resin composition. It is 20 to 70 parts by weight, more preferably 30 to 60 parts by weight. The content of the component (A) with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C) is preferably 30 to 80 parts by weight, more preferably 40 to 75 parts by weight, and 50 to 70 parts by weight. Parts are more preferred. By adjusting the amount of the component (A) within the above range, the heat resistance and chemical resistance of the cured film tend to be improved.

The content of the component (A1) with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C) is preferably 10 to 50 parts by weight, more preferably 15 to 45 parts by weight, and 20 to 40 parts by weight. Parts are more preferred. The content of the component (A2) with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C) is preferably 10 to 50 parts by weight, more preferably 15 to 45 parts by weight, and 20 to 40 parts by weight. Parts are more preferred. The ratio (A2) / (A1) of the content of the component (A1) to the content of the component (A2) is preferably 0.2 to 5, more preferably 0.5 to 2, and 0.7 to 1.5. Is even more preferable.

<(B) Photocurable compound>
The component (B) is a photocurable compound having at least one ethylenically unsaturated group. Ethylene unsaturated groups include (meth) acryloyl groups and vinyl groups. The component (B) forms a photocrosslinked network together with the component (A2) described above. The component (A2) contains a carboxyl group and contributes to the formation of a thermally crosslinked network together with the component (C), whereas the component (B) does not contain a carboxyl group, so that only the formation of a photocrosslinked network is possible. Contribute.

Specific examples of the compound having a (meth) acryloyl group include stearyl (meth) acrylate, lauryl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, and methoxypolyethylene glycol (meth) acrylate. Methoxydipropylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, nonyl Phenoxypolypropylene glycol (meth) acrylate, β- (meth) acryloyloxyethyl hydrogen phthalate, β- (meth) acryloyloxyethyl hydrogen succinate, 3-chloro-2-hydroxypropyl (meth) acrylate, 1- (meth) ) Monofunctional (meth) acrylic compounds such as acryloyloxypropyl-2-phthalate, polyoxyethylene alkyl ether (meth) acrylate; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) ) Acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2-hydroxy- 1- (meth) acryloxy-3- (meth) acryloxypropane, 1,4-butanediol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) Acrylate,
Neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, 2,4-diethyl-1,5-pentanediol di (meth) acrylate, 2-hydroxy- 1,3-Di (meth) acryloxypropane, 3-methyl-1,5-pentanediol di (meth) acrylate, 2,4-diethyl-1,5-pentanediol di (meth) acrylate, 1,4- Cyclohexanedimethanol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 4,4'-isopropyridene diphenol di (meth) acrylate, 2,2-bis [4-((meth) acryloxy) Ethoxy) phenyl] propane, 2,2-bis [4-((meth) acryloxy diethoxy) phenyl] propane, 2,2-bis [4-((meth) acryloxy polyethoxy) phenyl] propane, 2,2- Hydrogenated bis [4-((meth) acryloxy polyethoxy) phenyl] propane, 2,2-bis [4-((meth) acryloxy polypropoxy) phenyl] propane, bisphenol F EO modification (n = 2-50) Polyfunctional (meth) acrylic compounds such as di (meth) acrylate, bisphenol A EO modified (n = 2 to 50) di (meth) acrylate, bisphenol S EO modified (n = 2 to 50) di (meth) acrylate, etc. Can be mentioned.

The polyfunctional (meth) acrylic compound may be a compound having three or more (meth) acryloyl groups in one molecule. Examples of the trifunctional or higher functional (meth) acrylic compound include trimethyl propanthyl (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated totimethylol propanthyl (meth) acrylate, and propoxylated totimethylol propanthyl (meth) acrylate. , Isocyanurate tri (ethane (meth) acrylate), 1,3,5-tri (meth) acryloylhexahydro-s-triazine, tetramethylolmethanetetra (meth) acrylate, pentathritol tetra (meth) acrylate, ethoxylated Pentathritol tetra (meth) acrylate, propoxylated pentathritol tetra (meth) acrylate, ditrimethylolpropantetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol poly (meth) acrylate, etc. Be done.

Specific examples of the compound having a vinyl group include diallylamine, diallyldimethylsilane, diallyl disulfide, diallyl ether, diallyl cyanurate, diallyl isophthalate, diallyl terephthalate, 1,3-dialyloxy-2-propanol, diallyl sulfide diallyl maleate, and the like. Examples thereof include triallyl isocyanurate, triallyl 1,3,5-benzenecarboxylate, triallylamine, triallyl citrate, and triallyl phosphate.

The component (B) may be a polymer (oligoform) such as a urethane (meth) acrylate resin, an epoxy (meth) acrylate resin, a polyester (meth) acrylate resin, or an acrylic (meth) acrylate resin.

From the viewpoint of heat resistance of the cured film, it is preferable to use a polyfunctional (meth) acrylic compound containing two or more (meth) acryloyl groups in one molecule as the component (B). By using the polyfunctional (meth) acrylic compound, a photocrosslinked network consisting of the component (B) and the component (B) is formed. From the viewpoint of increasing the crosslink density, a polyfunctional (meth) acrylic compound containing three or more (meth) acryloyl groups in one molecule may be used as the component (B).

From the viewpoint of increasing the crosslink density of the cured film, the molecular weight of the polyfunctional (meth) acrylic compound containing three or more (meth) acryloyl groups is preferably 1000 or less, more preferably 800 or less, still more preferably 700 or less.

From the viewpoint of increasing the crosslink density, as the component (B), the functional group equivalent of the (meth) acryloyl group (the mass (g) of the compound containing 1 equivalent of the (meth) acryloyl group) is 300 or less. It is preferable to use an acrylic compound. The functional group equivalent of a polyfunctional (meth) acrylic compound is generally 80 or more. From the viewpoint of increasing the crosslink density of the cured film and improving the heat resistance, the functional group equivalent of the polyfunctional (meth) acrylic compound is more preferably 250 or less, and further preferably 200 or less. The functional group equivalent of the polyfunctional (meth) acrylic compound may be 180 or less or 150 or less.

As described above, as the component (B), it is preferable to use a trifunctional or higher functional (meth) acrylate having a functional group equivalent of (meth) acryloyl group of 300 or less. In a cured film in which a photocrosslinking network is formed by a trifunctional or higher polyfunctional (meth) acrylate, a plurality of polymer chains of the component (A2) are present in close proximity (the crosslink distance is short), so that the crosslink density is high and strong. Structure is likely to be formed, and heat resistance tends to be improved.

On the other hand, if the short-range crosslinked structure density of the polyfunctional (meth) acrylate having a small functional group equivalent (that is, a high functional group density) of the (meth) acryloyl group becomes excessively high, the flexibility of the cured film may decrease. is there. From the viewpoint of increasing the flexibility of the cured film while increasing the crosslink density and improving the heat resistance, as the component (B), in addition to the polyfunctional (meth) acrylic compound having a small functional group equivalent, polyfunctional (meth) acrylic Oligomers may be used. In particular, by using a trifunctional or higher functional (meth) acrylic compound and a polyfunctional (meth) acrylic oligomer as the component (B), a short-distance crosslinked structure and a long-distance crosslinked structure coexist, thus providing heat resistance. A cured film having flexibility while being enhanced is likely to be formed.

Examples of the polyfunctional (meth) acrylic oligomer include urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and acrylic (meth) acrylate. Urethane (meth) acrylate is preferable because a cured film having excellent flexibility is easily formed. The polyfunctional (meth) acrylic oligomer is preferably a bifunctional (meth) acrylic compound.

From the viewpoint of achieving both heat resistance and flexibility of the cured film, the molecular weight of the polyfunctional (meth) acrylic oligomer is preferably about 250 to 20,000, more preferably 300 to 15,000, and 350 to 10,000. More preferred. The molecular weight of the polyfunctional (meth) acrylic oligomer may be 400 or more, 5,000 or less, 3,000 or less, 2,000 or less, 1,500 or less, or 1,000 or less.

The (meth) acryloyl group of the polyfunctional (meth) acrylic oligomer may be acrylic or methacryloyl. As described above, from the viewpoint of enhancing photocurability, oligomers having acryloyl groups at both ends are generally used, but from the viewpoint of appropriately adjusting the photocrosslinkability to enhance the flexibility of the cured film, A methacrylic oligomer such as urethane dimethacrylate having a methacryloyl group at both ends may be used. When a methacrylic compound is used as the component (B), the reactivity of photoradical polymerization is lower than that when an acrylic compound is used, so that an unreacted (uncured) methacrylic compound tends to remain after photocuring. Since the unreacted oligomer acts as a plasticizer in the cured film, it is considered to contribute to the improvement of the flexibility of the cured film.

The content of the component (B) is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight, still more preferably 5 to 30 parts by weight, based on 100 parts by weight of the total solid content of the photosensitive resin composition. Parts, particularly preferably 10 to 20 parts by weight. The content of the component (B) with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C) is preferably 5 to 30 parts by weight, more preferably 8 to 25 parts by weight, and 10 to 20 parts by weight. Parts are more preferred. By adjusting the amount of the component (B) within the above range, it becomes easy to achieve both the flexibility and heat resistance of the cured film.

When the component (B) contains a polyfunctional (meth) acrylic compound having a trifunctionality or higher and a polyfunctional (meth) acrylic oligomer having a bifunctionality or higher, the component (A), the component (B) and the component (C) The content of the trifunctional or higher functional (meth) acrylic compound with respect to 100 parts by weight in total is preferably 1 to 25 parts by weight, more preferably 3 to 20 parts by weight, still more preferably 5 to 15 parts by weight. The content of the polyfunctional (meth) acrylic oligomer is preferably 1 to 25 parts by weight, more preferably 3 to 20 parts by weight, still more preferably 5 to 15 parts by weight.

<(C) Thermosetting resin>
A thermosetting resin is a compound having at least one thermosetting functional group in the molecule. As the thermosetting resin, an epoxy resin, an oxetane resin, an isocyanate resin, a blocked isocyanate resin, and a cyanate resin are preferable. Of these, an epoxy resin is preferable because it can react with the carboxyl group of the component (A) to form a thermally crosslinked network. A polyfunctional epoxy resin having two or more epoxy groups in one molecule is preferable because it can impart heat resistance to the cured film and also impart adhesiveness to conductors such as metal foils and circuit boards.

Examples of the polyfunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenyl type epoxy resin, phenoxy type epoxy resin, naphthalene type epoxy resin, and phenol novolac. Examples thereof include type epoxy resin, cresol novolac type epoxy resin, trisphenol methane type epoxy resin, dicyclopentadiene type epoxy resin, amine type epoxy resin and the like. The epoxy resin may be a modified epoxy resin such as urethane, rubber, chelate, or dimer acid. A commercially available epoxy resin may be used as it is as the component (C).

From the viewpoint of heat resistance and chemical resistance of the cured film, the epoxy equivalent of the epoxy resin (mass (g) of the compound containing 1 equivalent of the epoxy group) is preferably 2000 or less, and more preferably 1500 or less. The weight average molecular weight of the epoxy resin is preferably about 150 to 2000, more preferably about 200 to 1500.

The content of the component (C) is preferably 1 to 80 parts by weight, more preferably 5 to 50 parts by weight, and particularly preferably 10 to 30 parts by weight, based on 100 parts by weight of the total solid content of the photosensitive resin composition. It is a part by weight. The content of the component (C) with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C) is preferably 10 to 40 parts by weight, more preferably 15 to 35 parts by weight, and 20 to 30 parts by weight. The portion is more preferable. By adjusting the amount of the component (C) within the above range, it is easy to obtain a cured film having excellent heat resistance and chemical resistance and flexibility.

<(D) Metal inactivating agent>
The metal inactivating agent has the effect of inhibiting the curing reaction caused by the metal (ion) and suppressing the deterioration of the cured film by forming a complex with the metal and inactivating it. Examples of the inactivating agent capable of forming a complex with copper include polybasic acids such as oxalic acid and malonic acid; amino acids such as glycine and proline; amide compounds; and hydrazide compounds.

The metal inactivating agent is preferably a compound having a small amount of residue on the metal surface in the region where the film has been removed by development. When a metal inactivating agent having a strong binding force to a metal is used, the inactivating agent on the metal surface is not sufficiently removed even if rinsing is performed after development, and the residue of the inactivating agent is visually recognized as a defect. There is. In particular, when a colored cured film (typically a black cured film) formed by curing a photosensitive composition containing a colorant is patterned, the metal exposed on the surface is more exposed than the non-colored film. Adhesions are easily visible. Therefore, the metal inactivating agent preferably has an appropriate binding property to a metal such as copper and can be easily removed from the metal surface by development and / or rinsing after development.

N- (2H-1,2,4-triazole-) is a metal inactivating agent because it has an appropriate binding property to copper and is excellent in inactivating action and removing property from the metal surface. 5-Il) A benzamide derivative having a phenolic hydroxyl group such as salicylamide (commercially available, "Adecastab CDA-1" manufactured by ADEKA); N'1, N'12-bis (2-hydroxybenzoyl) dodecandihydrazide (commercially available). As ADEKA's "Adecastab CDA-1"), and N'-bis {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl} hydrazine (as a commercial product, ADEKA's "Adecastab CDA-" A hydrazide derivative having a phenolic hydroxyl group such as 10 ”) is preferable.

The content of the component (D) is preferably 0.1 to 1.0 parts by weight, more preferably 0.2 to 0.5 parts by weight, based on 100 parts by weight of the total solid content of the photosensitive resin composition. Is. By adjusting the amount of the component (D) within the above range, it is possible to suppress polymerization inhibition and improve the heat resistance of the cured film, and it is possible to suppress deterioration of performance and design due to the residue. Further, when the amount of the component (D) is within the above range, deterioration of the cured film in the vicinity of the interface with the metal tends to be suppressed.

<(E) Photopolymerization Initiator>
The photopolymerization initiator as the component (E) absorbs and activates light energy such as UV (ultraviolet light), and is subjected to a photoradical polymerization reaction of the ethylenically unsaturated groups of the components (A2) and (B). A compound (photoradical polymerization initiator) that initiates and promotes the formation of a photobridge network.

Examples of photoradical polymerization initiators are self-cleaving photoradical polymerization initiators such as benzoin compounds, acetophenones, aminoketones, oxime esters, acylphosphine oxide compounds, azo compounds; and benzophenones, benzoins. Hydrogen abstraction type photorades such as ethers, benzyl ketals, dibenzosverones, anthraquinones, xanthones, thioxanthones, halogenoacetophenones, dialkoxyacetophenones, hydroxyacetophenones, halogenobis imidazoles, and halogenotriazines. A polymerization initiator can be mentioned.

The photoradical polymerization initiator preferably has an absorption band at a wavelength of 405 nm. By using a photoradical polymerization initiator having an absorption band at a wavelength of 405 nm, the heat resistance of the cured film tends to be improved. The photoradical polymerization initiator preferably has an absorbance of 0.02 or more at a wavelength of 405 nm of a 0.001 wt% methanol solution measured by a visible-ultraviolet spectrophotometer using a quartz cell having an optical path length of 1 cm. In other words, it is preferable to use a photoradical polymerization initiator having an extinction coefficient at a wavelength of 405 nm of 20 [% ^-1 · cm ^{-1] or more.}

Examples of the photoradical polymerization initiator having an absorption band at 405 nm include acylphosphine oxide compounds, acetophenones, aminoketones, and oxime esters. Of these, oxime esters are preferable because of their high photosensitivity. Commercially available products of oxime esters having an absorption band at a wavelength of 405 nm include "ADEKA ARKULS NCI-831", "ADEKA ARKULS N-1717" and "ADEKA ARKULS N-1919" manufactured by ADEKA, and "ADEKA Arklus N-1919" manufactured by BASF. Irgacure OXE03 "and the like.

The content of the component (E) is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 10 parts by weight, and 0, based on 100 parts by weight of the total solid content of the components (A2) and (B). .5 to 5 parts by weight is more preferable. By setting the blending ratio as described above, the photosensitivity of the photosensitive resin composition can be improved, the photocuring reaction can be made more efficient, and overexposure can be prevented.

<(F) Colorant>
Colorants are added to give the cured film the desired color. The colorant is either a dye or a pigment. Examples of the colorant include a blue colorant, a red colorant, a yellow colorant, an orange colorant, a purple colorant and the like. By combining a plurality of colorants, cured films of various colors can be formed. Specific examples of colorants are shown below by color index numbers.

Examples of the blue colorant include phthalocyanine-based, anthraquinone-based, and dioxazine-based pigments such as C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 60; Dye-based Solvent Blue 35, 63, 68, 70, 83, 87, 94, 97, 122, 136, 67, 70 can be mentioned. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used as the blue colorant. In particular, a copper phthalocyanine-based colorant is preferable from the viewpoint of coloring power.

Examples of the red colorant include C.I. I. Pigment Red 122, 149, 166, 177, 179, 242, 224, 254, 264, 272.

Examples of the yellow colorant include C.I. I. Pigment Yellow 83, 110, 128, 138, 139, 150, 151, 154, 155, 180, 181.

Examples of the orange colorant include C.I. I. Pigment Orange 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 55, 59, 61, 63, 64, 71, 73.

Examples of the purple colorant include C.I. I. Pigment Violet 19, 23, 29, 30, 32, 36, 37, 38, 39, 40, 50; Solvent Violet 13, 36.

The above colorants can be combined to form a black colorant. A specific example of a combination of colorants for making the cured film black is shown below. The following ratios represent weight ratios.
The orange colorant is combined with the blue colorant 1.0 at a ratio of 1.5 to 3.0.
The red colorant is combined with the blue colorant 1.0 at a ratio of 1.2 to 3.0.
The purple colorant is combined with the blue colorant 1.0 at a ratio of 1.2 to 3.0.
The yellow colorant is combined at a ratio of 1.5 to 4 and the orange colorant is combined at a ratio of 1.0 to 2.5 with respect to the blue colorant 1.0.
The red colorant is combined in a ratio of 1.0 to 2.0 and the yellow colorant is combined in a ratio of 1.5 to 3.0 with respect to the blue colorant 1.0.
The yellow colorant is combined in a ratio of 1.0 to 3.0 and the purple colorant is combined in a ratio of 1.0 to 2.0 with respect to the blue colorant 1.0.
The orange colorant is combined in a ratio of 0.5 to 2.0 and the purple colorant is combined in a ratio of 0.5 to 2.0 with respect to the blue colorant 1.0.
Among the above, a combination of a blue colorant, an orange colorant, and a purple colorant is preferable because the blackness is excellent and the amount of the colorant can be easily adjusted.

The content of the component (F) may be appropriately set according to the type of the colorant and the color of the cured film. For example, in order to obtain a black cured film, the content of the component (F) with respect to 100 parts by weight of the total solid content of the photosensitive resin composition is preferably 3 parts by weight or more, and more preferably 4 parts by weight or more. From the viewpoint of colorability, there is no particular problem with the large amount of colorant, but as the amount of colorant increases, the photocurability tends to decrease, and in particular, the interface with the metal layer (light irradiation surface). Photocuring of the bottom interface) may be insufficient. Further, when the amount of the colorant is large, the thixotropics index becomes high, and there is a concern that clogging during ink filtration, deterioration of printability, and deterioration of resolution may occur. Therefore, the content of the component (F) with respect to 100 parts by weight of the total solid content of the photosensitive resin composition is preferably 10 parts by weight or less, more preferably 7 parts by weight or less.

<Other ingredients>
In addition to the above components (A) to (F), the photosensitive resin composition contains various additives such as a filler, an adhesive aid, a defoaming agent, a leveling agent, a polymerization inhibitor, and a flame retardant, if necessary. May include. Examples of the filler include inorganic fillers such as silica, mica, talc, barium sulfate, wallastonite, and calcium carbonate, and organic polymer fillers. Examples of the defoaming agent and the leveling agent include silicone compounds and acrylic compounds. Examples of the adhesion aid (also referred to as an adhesion imparting agent) include a silane coupling agent, a triazole-based compound, a tetrazole-based compound, and a triazine-based compound. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether and the like.

As the flame retardant, a phosphoric acid ester compound, a halogen-containing compound, a metal hydroxide, an organic phosphorus compound, a silicone compound and the like can be used. From the viewpoint of preventing environmental pollution, non-halogen flame retardants such as metal hydroxides and phosphorus compounds are preferable.

<Preparation of photosensitive resin composition>
A photosensitive resin composition can be obtained by mixing each of the above components and, if necessary, an appropriate solvent. Each of the above components may be subjected to operations such as pulverization / dispersion and defoaming, if necessary, before and / or after mixing. The pulverization / dispersion may be carried out using, for example, a kneading device such as a bead mill, a ball mill, or a three-roll.

The photosensitive resin composition can also be provided in the form of a kit containing some components and other components individually. For example, the photosensitive resin composition preparation kit contains the first agent and the second agent individually. Mixing multiple components that react in a solution state may reduce the storage stability of the solution, whereas storing them unmixed enhances the stability of the solution and transports it. -Flexible for lead time such as storage.

When the (A) carboxyl group-containing polymer and (D) the metal inactivating agent coexist in a solution, the viscosity of the above-mentioned photosensitive resin composition may increase with time. Therefore, from the viewpoint of enhancing storage stability, the first agent may be provided as a photosensitive resin composition preparation kit containing the component (A) and the second agent may contain the component (D). By storing the first agent and the second agent individually as a kit without mixing the component (A) and the component (D), the increase in viscosity can be suppressed.

The first agent of the kit may contain the component (B) in addition to the components (A1) and (A2), and the second agent of the kit contains the component (E) in addition to the component (D). You may be. By storing the photopolymerizable (photosensitive) components (A2) and (B) and the photopolymerization initiator (E) without mixing, photocuring in the storage environment can be suppressed. The second agent of the kit may contain the component (C). By storing the (A) carboxyl group-containing polymer and the (C) thermosetting resin such as an epoxy resin without mixing, the carboxyl group of the (A) component and the epoxy of the (C) component in the storage environment are stored. It is possible to prevent a reaction with a functional group such as a group.

When the photosensitive resin composition preparation kit is a two-component type composed of the first agent and the second agent, the component (F) may be contained in either the first agent or the second agent, and is contained in both of them. It may be. A photosensitive resin composition can be prepared by mixing the composition of the first agent and the composition of the second agent constituting the kit. The photosensitive resin composition preparation kit is not limited to the two-component type composed of the first agent and the second agent, and may be a type in which three or more liquids are mixed.

<Formation of cured film>
A cured film is formed by applying a photosensitive resin composition to a substrate, removing a solvent by heating if necessary, and then performing photocuring and thermosetting. Since the photosensitive resin composition has a colorant, a colored cured film colored in black or the like can be obtained. By using the above-mentioned photosensitive composition, a cured film having excellent heat resistance can be formed on a metal such as a copper foil.

In general, when a resin composition containing a colorant such as black is photocured, the cured film is insufficiently cured in the vicinity of the interface on the opposite side of the light irradiation surface, and may be inferior in heat resistance. In particular, when a cured film is formed on a metal, the heat resistance tends to decrease. One of the causes of the decrease in heat resistance when the cured film is formed on the metal is considered to be polymerization inhibition near the interface between the metal and the cured film and decomposition of the resin. In particular, it is considered that the presence of metal ions promotes the decomposition of the resin, so that the adhesion at the interface with the metal is lowered and the heat resistance of the cured film is likely to be lowered.

As described above, when the photosensitive resin composition contains the (D) metal inactivating agent, the decomposition and polymerization inhibition of the resin caused by the metal are suppressed, and the adhesion at the interface between the metal and the cured film is improved. It is considered that the heat resistance is improved because of the improvement. Further, since the photosensitive resin composition contains the component (A2) that contributes to both the formation of the photocrosslinking network and the formation of the thermocrosslinking network, even if the photocuring in the vicinity of the metal interface is not sufficient, the crosslinking is performed by thermal crosslinking. It is considered that the improvement of the property also contributes to the improvement of the heat resistance.

When a photopolymerization initiator having an absorption band at a wavelength of 405 nm is used as the component (E), the heat resistance of the cured film tends to be further improved. By using a photopolymerization initiator having an absorption band at a long wavelength, even if the resin composition has a colorant, photocuring at the bottom (near the interface with the metal) is likely to proceed, which is heat resistant. It is thought that it contributes to the improvement of sex.

When the coating film of the photosensitive resin composition was irradiated with active light such as ultraviolet rays or short-wavelength visible light, the photopolymerization initiator in the vicinity of the irradiation surface was activated by absorbing the light and was not absorbed in the vicinity of the irradiation surface. Light reaches the bottom (near the interface with the metal). Therefore, in general, photocuring is more likely to proceed on the irradiated surface side than on the bottom. In particular, when the photosensitive resin composition contains a colorant, the colorant also absorbs the active light in addition to the photopolymerization initiator, so that the amount of the active light reaching the bottom is small and the amount of the active light reaches the bottom is smaller than that of the light irradiation surface. , The photocuring of the bottom tends to be insufficient.

Since short-wavelength light has a relatively high energy, in photocuring by irradiation with active light, short-wavelength light is preferentially used near the light-irradiated surface, and long-wavelength light that is not absorbed near the light-irradiated surface is used. Light easily reaches the bottom. By using a photopolymerization initiator having an absorption band at a long wavelength (405 nm) as the component (E), photocuring by the long wavelength light reaching the bottom is likely to proceed. Therefore, even when the composition has a colorant, it is considered that the photocuring reaction at the bottom can be maintained and the heat resistance of the cured film is improved.

That is, by containing the metal inactivating agent as the component (D), a photopolymerization initiator having an absorption band at a long wavelength while suppressing curing inhibition at the bottom (near the interface with the metal) and decomposition of the resin can be obtained. By using it, the photocuring reactivity at the bottom is improved. Further, even when the composition contains a colorant such as black, the thermosetting proceeds substantially uniformly without a difference in the thickness direction of the film, so that the insufficient curing of the bottom can be compensated. Therefore, it is considered that a cured film having excellent adhesion at the interface with the metal, having a high crosslink density even in the vicinity of the interface with the metal, and having excellent heat resistance is formed.

The formation of the cured film using the photosensitive resin composition can be carried out by various known methods. The photosensitive resin composition (solution) may be applied onto the substrate by screen printing, curtain roll, reverse roll, spray coating, rotary coating using a spinner, or the like. The thickness of the coating film may be adjusted so that the thickness after drying is about 5 to 100 μm, preferably about 10 to 50 μm. When drying by heating, the drying temperature is preferably 120 ° C. or lower, more preferably 40 to 100 ° C. from the viewpoint of suppressing the thermosetting reaction.

Photocuring is performed by exposing the dried coating film. At the time of exposure, a relief pattern can be formed by arranging a photomask on the coating film, selectively exposing a part of the surface of the coating film, and then developing the photomask. At the time of exposure, it irradiates active rays such as ultraviolet rays and visible rays. When a photopolymerization initiator having an absorption band at a long wavelength is used as the component (E), it is preferable to perform exposure from a light source containing light having a short wavelength of visible light (for example, 400 to 450 nm). When exposure is performed using an LED, it is preferable to use an LED having an emission peak wavelength longer than 385 nm.

An alkaline aqueous solution is generally used as the developing solution, and an organic alkaline aqueous solution and an inorganic alkaline aqueous solution can be used without particular limitation. The developer may contain an organic solvent that is miscible with water, such as metall, etanol, n-propanol, isopropanol, and N-methyl-2-pyrrolidone. The alkali concentration of the developer is generally 0.01 to 20% by weight, preferably 0.02 to 10% by weight, and the temperature of the developer is generally 0 to 80 ° C, preferably 10 to 60 ° C. The relief pattern after development is preferably rinsed with a rinsing solution such as water or an acidic aqueous solution.

By performing heat treatment after development, thermosetting proceeds and a heat-crosslinked network consisting of the above components (A) and (C) is formed, so that a cured film having high heat resistance can be obtained. The thickness of the cured film is determined in consideration of the wiring thickness and the like, and is, for example, about 2 to 50 μm.

From the viewpoint of sufficiently advancing thermosetting and suppressing oxidation of metal wiring due to heat, the curing temperature (maximum temperature at the time of thermosetting) is preferably 100 to 250 ° C, more preferably 120 to 200 ° C, and 130 to 130 to 180 ° C. is more preferable.

The cured film obtained from the photosensitive resin composition has, for example, a resolving power of about 10 to 1000 μm, and is therefore preferably used as a surface protective material for a printed wiring board. Further, since the cured film is excellent in flexibility, it is also suitably used as a cured film of a flexible printed wiring board provided with metal wiring on a flexible film such as a polyimide film. Further, the photosensitive resin composition can also be used for forming various wiring coating protective materials, photosensitive heat-resistant adhesives, electric wire / cable insulating coatings and the like.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

[Synthesis example]
In the following synthesis example, a polymer having (A1) carboxyl group and no photopolymerizable functional group was polymerized. The properties of the solutions and polymers obtained in Synthesis Examples 1 to 3 were evaluated by the following methods.

<Solid content concentration>
The measurement was performed according to JIS K 5601-1-2. The drying conditions were 170 ° C. × 1 hour.

<Weight average molecular weight>
The measurement was carried out by gel permeation chromatography (GPC) under the following conditions.
Equipment used: Tosoh HLC-8220 GPC equivalent Column: Tosoh TSK gel Super AWM-H (6.0mm ID x 15cm) x 2 Guard columns: Tosoh TSK guard column Super AW-H
Eluent: 30mM LiBr + 20mM H ₃ PO ₄ in DMF
Flow velocity: 0.6 mL / min
Column temperature: 40 ° C
Detection conditions: RI: Polarity (+), Response (0.5 sec)
Sample concentration: Approximately 5 mg / mL
Molecular weight standard product: PEG (polyethylene glycol)

<Acid value>
The measurement was performed according to JIS K 5601-2-1.

(Synthesis Example 1)
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen introduction tube was charged with 100.0 g of methyltriglime (1,2-bis (2-methoxyethoxy) ethane) as a solvent for polymerization under a nitrogen stream. The temperature was raised to 80 ° C. with stirring. To this, 12.0 g (0.14 mol) of methacrylic acid, 28.0 g (0.16 mol) of benzyl methacrylate and 60.0 g (0.42 mol) of butyl methacrylate, which were premixed at room temperature, were added. And 0.5 g of azobisisobutyronitrile as a radical polymerization initiator was added dropwise from a dropping funnel over 3 hours while keeping the temperature at 80 ° C. After completion of the dropping, the temperature of the reaction solution was raised to 90 ° C. while stirring, and the reaction solution was stirred for another 2 hours while maintaining the temperature at 90 ° C. to obtain an acrylic polymer (A1-1) containing a carboxyl group in the molecule. Solution was obtained. The solid content concentration of the solution was 50%, the weight average molecular weight of the polymer was 48,000, and the acid value was 78 mgKOH / g.

(Synthesis Example 2)
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen introduction tube was charged with 30.00 g of methyl triglime and 10.31 g (0.050 mol) of norbornene diisocyanate as a solvent for polymerization, and stirred under a nitrogen stream. While warming to 80 ° C., it was dissolved. To this solution, 50.00 g (0.025 mol) of polycarbonate diol (manufactured by Asahi Kasei Co., Ltd., trade name: PCDL T5652, weight average molecular weight 2000) and 3.70 g (0.02 mol) of 2,2-bis (hydroxymethyl) butanoic acid were added. A solution prepared by dissolving 30.00 g of methyl triglime (025 mol) was added dropwise from a dropping funnel over 1 hour. This solution was heated and stirred at 80 ° C. for 5 hours to obtain a solution of urethane polymer (A1-2) containing a carboxyl group in the molecule. The solid content concentration of the solution was 52%, the weight average molecular weight of the polymer was 5,600, and the acid value was 22 mgKOH / g.

(Synthesis Example 3)
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen introduction tube, 35.00 g of methyl triglime and 10.31 g (0.050 mol) of norbornene diisocyanate were charged as a solvent for polymerization and stirred under a nitrogen stream. While warming to 80 ° C., it was dissolved. A solution prepared by dissolving 50.00 g (0.025 mol) of polycarbonate diol in 35.00 g of methyl triglime was added dropwise to this solution from a dropping funnel over 1 hour, and the mixture was heated and stirred at 80 ° C. for 2 hours, and then 3,3. 15.51 g (0.050 mol) of',4,4'-oxydiphthalic dianhydride was added, the temperature was raised to 190 ° C., and the mixture was heated and stirred for 1 hour. Then, the mixture was cooled to 80 ° C., 3.60 g (0.200 mol) of pure water was added, the temperature was raised to 110 ° C., the mixture was heated under reflux for 5 hours, and a urethaneimide polymer (A1) containing a carboxyl group in the molecule was added. The solution of -3) was obtained. The solid content concentration of the solution was 53%, the weight average molecular weight of the polymer was 9,200, and the acid value was 86 mgKOH / g.

[Preparation of resin compositions of Examples, Comparative Examples and Reference Examples]
The compositions of the formulations shown in Table 1 were dissolved in methyl triglime, stirred by a stirrer, and then passed twice with a 3-roll mill. Then, defoaming was performed with a defoaming device to prepare a uniform solution. The amount of methyl triglime as a solvent (the total amount of the solvent including the solvent contained in the polymer solution of the above synthesis example) is 60 with respect to 100 parts by weight of the total (solid content) of the components (A) to (C). It was a weight part. Further, in addition to the components shown in Table 1, 0.2 parts by weight of a butadiene defoamer (“Floren AC-2000” manufactured by Kyoeisha Chemical Co., Ltd.) was added to each resin composition.

[Formation and evaluation of cured film]
<Photosensitivity>
On a polyimide film having a thickness of 25 μm (“Apical 25 NPI” manufactured by Kaneka Corporation), the photosensitive resin composition was cast and applied to an area of 100 mm × 100 mm using a baker-type applicator so that the final dry thickness was 20 μm. It was dried at 80 ° C. for 20 minutes. After placing a negative photomask with line width / space width = 100 μm / 100 μm and irradiating it with ultraviolet rays with an integrated exposure amount of ^{300 mJ / cm 2 using a high-pressure mercury lamp, 1.0% by weight} A sodium carbonate aqueous solution (30 ° C.) was sprayed at a discharge pressure of ^{1.0 kgf / mm 2 for 90 seconds for development.} After washing with pure water, it was heat-cured in an oven at 150 ° C. for 30 minutes to prepare a pattern-cured film (relief pattern) of the photosensitive resin composition.

When the relief patterns formed using the compositions of Examples, Reference Examples and Comparative Examples were observed with an optical microscope, the pattern was markedly thickened and the development residue was not observed regardless of which composition was used. A photosensitive pattern of line width / space width = 100/100 μm could be drawn.

<Heat resistance>
A copper foil of a flexible copper-clad laminate made by laminating a polyimide film with a thickness of 25 μm (“Apical 25 NPI” manufactured by Kaneka) and an electrolytic copper foil with a thickness of 12 μm with a polyimide adhesive, and a stripe of line width / space width = 100 μm / 100 μm. The shape pattern was etched and immersed in a 10% by volume sulfuric acid aqueous solution for 1 minute to surface-treat the copper foil, and then washed with pure water to prepare a flexible printed substrate. The photosensitive resin composition was cast / coated, dried, exposed, developed and heat-cured in the same manner as described above to form a cured film on the flexible printed circuit board. At the time of exposure, the entire surface was irradiated with ultraviolet rays without using a photomask.

This sample was immersed in a solder bath, pulled up 10 seconds later, and subjected to appearance observation and tape peeling test, and evaluated according to the following criteria. In evaluation 1, the temperature of the solder bath was 320 ° C., and in evaluation 2, the temperature of the solder bath was 350 ° C.
◯: No change in appearance before and after the test, and the cured film did not peel off in the tape peeling test Δ: No change in appearance, but the cured film peeled off in the tape peeling test ×: Swelling or peeling of the cured film after the test Those with changes in appearance such as

<Flexibility>
Using a baker-type applicator, the photosensitive resin composition was cast and applied to a polyimide film having a thickness of 25 μm (“Apical 25 NPI” manufactured by Kaneka Corporation) over an area of 100 mm × 100 mm so that the final dry thickness was 20 μm. It was dried at ° C. for 20 minutes. The test piece was cut into a size of 15 mm × 100 mm, exposed, developed and heat-cured in the same manner as described above to form a cured film on the polyimide film, and a sample for flexibility evaluation was prepared.

The evaluation sample was bent 180 ° so that the cured film was on the outside, and a load of 200 g was placed on the bent portion for 3 seconds. After removing the load, the bent portion was visually observed to evaluate the presence or absence of cracks. This work was carried out until cracks were formed in the cured film, and the number of times that no cracks were not generated was defined as the number of folding resistance. For example, if a crack occurs in the second test, the number of breaks is 1.

Table 1 lists the formulations of the photosensitive resin compositions of Examples, Reference Examples and Comparative Examples, and the evaluation results of the cured film. The numerical value of each component in the table is a blending amount (part by weight) in which the total (resin content) of the components (A) to (C) is 100 parts by weight, and the details of each component are as shown below.

(1) "KAYARAD UXE-3000" manufactured by Nippon Kayaku Co., Ltd .; Carbitol acetate diluted solution of acid-modified epoxy acrylate having a urethane skeleton (weight average molecular weight 10,000, acid value 98 mgKOH / g)
(2) "KAYARAD CCR-1235" manufactured by Nippon Kayaku Co., Ltd. Carbitol acetate / solventnaphtha diluted solution of acid-modified epoxy acrylate resin having a cresol novolak skeleton (weight average molecular weight 8,000, acid value 80 mgKOH / g)
(3) "KAYARAD DPHA" manufactured by Nippon Kayaku Co., Ltd .; a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (4) "GENOMER 4297" manufactured by Rahn; aliphatic urethane methacrylate (weight average molecular weight 400 to 600)
(5) Mitsubishi Chemical "jER828"; bisphenol A type epoxy resin (average molecular weight 370, epoxy equivalent 190)
(6) ADEKA "ADEKA STAB CDA-1"; N- (2H-1,2,4-triazole-5-yl) salicylamide (7) ADEKA "ADEKA STAB CDA-10";N'-bis {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl} hydrazine (8) BASF "Irgacure OXE02"; Etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole -3-Il]-, 1- (o-acetyloxime); Absorbance of 0.001% methanol solution at a wavelength of 405 nm: 0.002
(9) "ADEKA Arkuru's NCI-831" manufactured by ADEKA; nitro group-substituted carbazole-type oxime ester photoradical polymerization initiator; absorbance of 0.001% methanol solution at a wavelength of 405 nm: 0.03
(10) Black colorant: A colorant obtained by mixing the following blue colorant, orange colorant and purple colorant at a weight ratio of 1: 1: 1. Blue colorant: "GLVO" manufactured by BASF; Pigment Blue 15: 3
Orange colorant: Clariant "GRL"; Pigment Orange 43
Purple colorant: Clariant "ER-02"; Pigment Violet 19

In Comparative Example 1 containing no component (D) (metal inactivating agent), the solder heat resistance of the cured film was inferior. In Comparative Example 2 using a photopolymerization initiator having a large absorbance at a wavelength of 405 nm, the solder heat resistance at 320 ° C. was improved as compared with Comparative Example 1, but the solder heat resistance at 350 ° C. was not improved. It was. In Comparative Example 3 using the composition containing no colorant, the solder heat resistance was higher than that of Comparative Examples 1 and 2.

In Example 5 in which the benzamide derivative was added as the component (D), improvement in solder heat resistance was observed as compared with Comparative Example 1. In Reference Example 1 using the composition containing no colorant, the solder heat resistance was superior to that of Example 1. From these results, it can be seen that the heat resistance of the cured film tends to decrease in the composition containing the colorant, but the heat resistance is improved by adding the metal inactivating agent.

In Example 3 in which the component (E) (photopolymerization initiator) was changed to a photopolymerization initiator having an absorption band at a wavelength of 405 nm, the heat resistance was further improved as compared with Example 5. Examples 1, 2, 4, 6 to 8 using the same photopolymerization initiator as in Example 3 also showed excellent heat resistance as in Example 3. From these results, in the photosensitive resin composition containing a colorant, by using a metal inactivating agent and a photopolymerization initiator having an absorption band at a long wavelength, a cured film having excellent heat resistance can be obtained. It turns out that it can be formed.

Focusing on the flexibility of the cured film, in Example 2 using the polymer (A1-2) as the component (A1) and in Example 3 using the polymer (A1-3), compared with Example 1. It can be seen that the number of folding resistances has increased and the flexibility has improved. Further, as compared with Example 6 in which only the polyfunctional acrylate was used as the component (B), in Example 5 in which the polyfunctional acrylate and urethane methacrylate were used in combination, the flexibility of the cured film was improved, and compared with Example 8. A similar tendency was observed in comparison with Example 7. In Example 5 in which a polymer having a urethane skeleton was used as the component (A2), the flexibility of the cured film was improved as compared with Example 7, and the same tendency was observed in the comparison between Example 6 and Example 8. Was seen.

From these results, the components (A1) and (B) that contribute to the formation of the thermally crosslinked network, and the components (A2) that contribute to the formation of the photocrosslinked network and the thermally bridged network have a large molecular weight (functional group equivalent). It can be seen that a cured film having high heat resistance and excellent flexibility can be formed by using a (large) compound or a polymer (oligomer) having a urethane chain.

Claims (22)

(A1) A polymer having a carboxyl group and no ethylenically unsaturated group;
(A2) Polymer having carboxyl group and ethylenically unsaturated group;
(B) Compound having ethylenically unsaturated group and no carboxyl group (C) Thermosetting resin;
(D) Metal inactivating agent;
A photosensitive resin composition containing (E) a photopolymerization initiator; and (F) a colorant. The photosensitive resin composition according to claim 1, wherein the photopolymerization initiator (E) has an absorption band at a wavelength of 405 nm. The photosensitive resin composition according to claim 1 or 2, wherein the colorant (F) is a black colorant. The (F) colorant contains an organic pigment and contains
The invention according to any one of claims 1 to 3, wherein the organic pigment contains at least one selected from the group consisting of a blue organic pigment, an orange organic pigment, a yellow organic pigment, a red organic pigment, and a purple organic pigment. Photosensitive resin composition. The photosensitive resin according to any one of claims 1 to 4, wherein the photosensitive resin (A2) contains a polymer containing at least one carboxyl group and two or more (meth) acryloyl groups in one molecule. Composition. The photosensitive resin composition according to claim 5, which contains an epoxy (meth) acrylate as the (A2). The photosensitive resin composition according to any one of claims 1 to 6, wherein (B) contains a compound containing two or more (meth) acryloyl groups in one molecule. As the above (B), claims 1 to 1 contain a polyfunctional (meth) acrylate containing three or more (meth) acryloyl groups in one molecule and having a functional group equivalent of the (meth) acryloyl group of 80 to 300. 6. The photosensitive resin composition according to any one of 6. As the above (B), a polyfunctional (meth) acrylic compound containing three or more (meth) acryloyl groups in one molecule and having a functional group equivalent of 80 to 300 (meth) acryloyl groups and 2 in one molecule. The photosensitive resin composition according to any one of claims 1 to 6, which comprises a polyfunctional (meth) acrylic oligomer containing more than one (meth) acryloyl group. The photosensitive resin composition according to any one of claims 1 to 9, which contains a polyfunctional epoxy resin having two or more epoxy groups in one molecule as the (C). Any one of claims 1 to 10, wherein each of (A1) and (A2) has an acid value of 5 to 200 mgKOH / g and a weight average molecular weight of 1,000 to 1,000,000. The photosensitive resin composition according to. The photosensitive resin composition according to any one of claims 1 to 11, wherein the photopolymerization initiator (E) is an oxime ester. Any one of claims 1 to 12 containing, as the (D) metal inactivating agent, at least one selected from the group consisting of a benzamide derivative having a phenolic hydroxyl group and a hydrazide derivative having a phenolic hydroxyl group. The photosensitive resin composition according to the section. The total content of (A1), (A2), (B) and (C) is 100 parts by weight, and the total content of (A1) and (A2) is 30 to 80 parts by weight. The photosensitive resin composition according to any one of claims 1 to 13, wherein the content of B) is 5 to 30 parts by weight, and the content of (C) is 10 to 40 parts by weight. A photosensitive resin composition preparation kit for preparing the photosensitive resin composition according to any one of claims 1 to 14.
Contains the first and second agents separately
The first agent comprises said (A1) and said (A2).
The second agent comprises the above (D).
Photosensitive resin composition preparation kit. The photosensitive resin composition preparation kit according to claim 15, wherein the second agent comprises the above (E). The photosensitive resin composition preparation kit according to claim 15 or 16, wherein the second agent comprises (C). The photosensitive resin composition preparation kit according to any one of claims 15 to 17, wherein the first agent comprises (B). A cured film made of a cured product of the photosensitive resin composition according to any one of claims 1 to 14. A printed wiring board with a cured film, which is in contact with the metal wiring of the printed wiring board and includes the cured film according to claim 19. The printed wiring board with a cured film according to claim 20, wherein the printed wiring board has flexibility. The photosensitive resin composition according to any one of claims 1 to 14 is applied to a metal wiring forming surface of a printed wiring board to form a coating film.
At least a part of the surface of the coating film is irradiated with active light to cure the light.
The coating film after photo-curing is heated to perform thermosetting.
A method for manufacturing a printed wiring board with a cured film.