JP2011028129A - Photosensitive heat curing-type resin composition and flexible printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkali development-type photosensitive heat curing-type resin composition, which can form a film free from a halogen, having a high level of flame retardancy, having excellent low warpage properties, and having excellent flexibility, resolution, soldering heat resistance, moisture resistance, adhesion, chemical resistance and other properties; and to provide a flexible printed wiring board using the same. <P>SOLUTION: The photosensitive heat curing-type resin composition comprises: (A) a urethane resin which is prepared using at least (a) a polyisocyanate compound, (b) a polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, (d) a polyol compound other than the components (b) and (c), and (e) a monohydroxy compound as starting materials, has an (meth)acryloyl group and a carboxyl group, and is soluble in a dilute alkali solution; (B) an epoxy resin; (C) an organophosphorus compound; (D) a photopolymerization initiator; and (E) a diluting agent. The flexible printed wiring board using the same is also provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an alkali development type photosensitive thermosetting resin composition having a high level of flame retardancy while being halogen-free, and excellent in heat resistance, flex resistance, low warpage, and the like. The present invention relates to a flexible printed wiring board using a simple composition.

  In order to protect the wiring pattern formed on the substrate by screen printing or the like from the external environment, or to prevent the solder from adhering to unnecessary parts in the soldering process performed when surface mounting electronic components on the printed wiring board For example, a protective film called a cover coat or a solder mask is used. This protective film covers the printed wiring board and exhibits a protective function.

  As a material for such a protective film, for example, an epoxy resin composition is used for a thermosetting solder resist, but it is difficult to use an epoxy resin as it is because it easily burns. Therefore, in order to impart flame retardancy to the resin composition, a halogen-based flame retardant has been added, or a brominated epoxy resin containing bromine in the skeleton has been used (for example, see Patent Document 1).

  However, since decabromodiphenyl oxide, the most typical brominated flame retardant, was reported to produce toxic brominated dibenzooxide and furan during incineration, the safety of brominated flame retardants as a whole is suspected. It has become. In addition, conventional incineration of resins using halogenated flame retardants generates toxic gases such as dioxins, which have a large environmental impact during incineration and disposal.

  Further, in recent years, organophosphorus flame retardants have been used instead of halogen flame retardants in order to cope with environmental problems. However, this organophosphorus flame retardant is not so excellent in flame retardant properties. When trying to impart equivalent flame retardancy to a resin composition, it is added compared to halogen flame retardants. The amount must be increased, and the composition has problems such as deterioration of properties and bleeding. In order to improve such a problem of characteristics, a resin system using a compound having a specific structure has been studied, but it is not yet sufficient (see, for example, Patent Documents 2 and 3).

  In recent years, flexible wiring boards have become lighter and thinner with the reduction in size and weight of electronic devices, and as a result, the effects of the flexibility and cure shrinkage of the resin composition to be coated are becoming more prominent. . Therefore, in the present situation, the curing type overcoat agent cannot sufficiently satisfy the required performance in terms of warpage due to flexibility and curing shrinkage.

  Various studies have been made to solve such problems at present, and for example, urethane compounds obtained by reacting polycarbonate diol, polycaprolactone diol, silicone-containing diol and diisocyanate compounds have been proposed ( For example, refer to Patent Documents 4 to 6.) However, the cured product has low heat resistance and has a drawback that it cannot withstand the increase in solder reflow temperature due to the recent lead-free process.

JP-A-9-54434 JP 2001-72835 A JP 2007-147720 A JP 2002-229201 A JP 2008-45032 A JP 2008-297440 A

  Accordingly, an object of the present invention is to provide a high level of flame retardancy without using a halogen-based flame retardant for flame retardancy of a resin composition, and at the same time, low warpage, flexibility, resolution, solder heat resistance. It is an object of the present invention to provide an alkali development type photosensitive thermosetting resin composition capable of forming a film excellent in properties, moisture resistance, adhesion, chemical resistance, and the like, and a flexible printed wiring board using the same.

  As a result of intensive studies to solve the above-described problems, the inventors of the present invention provide an alkali development type photosensitive thermosetting resin composition containing a urethane resin manufactured using a specific compound as a raw material. The present invention has been completed by finding that the above-mentioned problems can be solved.

  That is, the photosensitive thermosetting resin composition of the present invention comprises (A) at least (a) a polyisocyanate compound, (b) a polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, (d) ( (b) and a polyol compound other than the component (c), and (e) a urethane resin having a (meth) acryloyl group and a carboxyl group, which is produced from a monohydroxy compound as a raw material, B) An epoxy resin, (C) an organophosphorus compound, (D) a photopolymerization initiator, and (E) a diluent are contained.

  The flexible printed wiring board of the present invention is a flexible printed wiring board comprising a copper layer directly on the polyimide layer or via an adhesive layer, and the photosensitive thermosetting type of the present invention is formed on the surface of the copper layer. It has the resin layer formed with the resin composition, It is characterized by the above-mentioned.

  According to the photosensitive thermosetting resin composition of the present invention, it has a high level of flame retardancy without using a brominated epoxy resin or a halogen-based flame retardant, and has low warpage, flexibility, and resolution. It is possible to form a film excellent in solder heat resistance, moisture resistance, adhesion, chemical resistance and the like.

  In addition, since the flexible printed wiring board of the present invention uses the photosensitive thermosetting resin composition having the above-described excellent characteristics, it can reduce environmental burden and at the same time has excellent quality and reliability. Can be.

  Hereinafter, the present invention will be described in detail.

  The urethane resin soluble in the dilute alkali solution of the component (A) used in the present invention is at least (a) a polyisocyanate compound, (b) a polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, d) Polyurethane compounds other than components (b) and (c), and (e) a urethane resin having a (meth) acryloyl group and a carboxyl group, which is produced from a monohydroxy compound as a raw material and soluble in a dilute alkali solution Preferably, (f) an epoxy acrylate compound is further used as a raw material. In this component, the (meth) acryloyl group in the molecule is polymerized by radicals generated from the photopolymerization initiator of the component (D) described later when irradiated with active energy rays such as ultraviolet rays. As a result, the resin composition It has the function of insolubilizing objects.

  Examples of the (a) polyisocyanate compound used as a raw material for this urethane resin include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 1,3- Trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,9-nonamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,2′-diethyl ether diisocyanate, diphenylmethane-4,4′-diisocyanate, (o, m, or p) -xylene diisocyanate, methyl Bis (4-cyclohexyl isocyanate), cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, 3,3′-methylene ditolylene-4 , 4′-diisocyanate, 4,4′-diphenyl ether diisocyanate, tetrachlorophenylene diisocyanate, norbornane diisocyanate, and diisocyanates such as hydrogenated (1,3- or 1,4-) xylylene diisocyanate. These can be used alone or in combination of two or more.

  (A) Usually, diisocyanate having two isocyanate groups (—NCO) in one molecule as described above is used as the polyisocyanate compound, but the obtained urethane resin of component (A) does not gel. Polyisocyanates having 3 or more isocyanate groups per molecule, such as triphenylmethane triisocyanate, can also be used. Such polyisocyanate is preferably used in combination with diisocyanate.

  (A) When the polyisocyanate compound having an alicyclic structure having 6 to 30 carbon atoms other than carbon atoms in the isocyanate group is used as the polyisocyanate compound, the photosensitive thermosetting type of the present invention. The cured product formed from the resin composition is particularly excellent in chemical resistance.

  Examples of the polyisocyanate compound having such an alicyclic structure include 1,4-cyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), hydrogenated 1,3-xylylene diisocyanate, and hydrogenated 1,4. -Xylylene diisocyanate etc. are mentioned.

  The polyisocyanate compound having an alicyclic structure is desirably contained in an amount of 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more based on the total amount of (a) polyisocyanate compound.

  When the polyisocyanate compound having an aliphatic structure having 6 to 30 carbon atoms other than carbon atoms in the isocyanate group is used as the polyisocyanate compound (a), the photosensitive thermosetting of the present invention. The cured product formed from the mold resin composition is particularly excellent in flexibility.

  Examples of the polyisocyanate compound having such an aliphatic structure include hexamethylene diisocyanate, trimethylhexane diisocyanate, and methylpentane diisocyanate.

  The polyisocyanate compound having an aliphatic structure is desirably contained in an amount of 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more based on the total amount of (a) polyisocyanate compound.

  (B) Examples of polyol compounds having a bisphenol skeleton (hereinafter also referred to as bisphenol-containing polyol compounds) include bisphenol A alkylene oxide adducts, bisphenol F alkylene oxide adducts, bisphenol S alkylene oxide adducts, and bisphenoxyethanol fluorene. Can be mentioned. (Meth) acrylic acid may be added to these compounds for the purpose of imparting radical polymerizability. (B) The polyol compound which has bisphenol skeleton can be used individually by 1 type or in combination of 2 or more types. The (b) polyol compound having a bisphenol skeleton preferably has a number average molecular weight of 250 to 50,000.

  (C) Examples of the dihydroxy compound having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, N, N-bishydroxyethylglycine, N, N-bishydroxyethylalanine and the like. Among them, 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid are preferable from the viewpoint of solubility in a solvent. (C) The dihydroxy compound which has a carboxyl group can be used individually by 1 type or in combination of 2 or more types.

  Preferred examples of the polyol compound other than the components (d), (b) and (c) include (i) polycarbonate polyol, (ii) polyether polyol, (iii) polyester polyol, and (iv) polylactone as shown below. Examples include polyols, (v) polybutadiene polyols, and (vi) polyols that do not contain oxygen atoms other than oxygen atoms in the hydroxyl group and have 18 to 72 carbon atoms (excluding polybutadiene polyols).

（式中、Ｒはジオールから水酸基を除いた残基であり、ｎは正の整数、好ましくは２〜５０の整数である） (I) As polycarbonate polyol, what is represented by the following general formula (1) obtained by making a C4-C18 diol react with carbonate ester or phosgene, for example is mentioned.

(In the formula, R is a residue obtained by removing a hydroxyl group from a diol, and n is a positive integer, preferably an integer of 2 to 50)

  Specific examples of the diol having 4 to 18 carbon atoms include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1, 5-pentanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,10- Examples include decamethylene glycol and 1,2-tetradecanediol.

  (I) The polycarbonate polyol may be a polycarbonate polyol having a plurality of types of alkylene groups in its skeleton (copolymerized polycarbonate polyol). Use of such a copolymerized polycarbonate polyol can be advantageous in preventing crystallization of the (A) urethane resin. In consideration of solubility in a solvent, it is preferable to use a polycarbonate polyol having a branched skeleton and having a hydroxyl group at the molecular chain terminal. These polycarbonate polyols are preferably used as a combination component.

（式中、Ｒはジオールから水酸基を除いた残基であり、ｎは正の整数、好ましくは４〜５０の整数である） (Ii) The polyether polyol is obtained, for example, by dehydration condensation of a diol having 2 to 12 carbon atoms or ring-opening polymerization of an oxirane compound, oxetane compound or tetrahydrofuran compound having 2 to 12 carbon atoms, What is represented by the following general formula (2) is mentioned.

(In the formula, R is a residue obtained by removing a hydroxyl group from a diol, and n is a positive integer, preferably an integer of 4 to 50)

  Specific examples of the polycarbonate polyol represented by the general formula (2) include polyethylene glycol, polypropylene glycol, poly-1,2-butylene glycol, polytetremethylene glycol, and poly-3-methyltetramethylene glycol. Illustrated. Moreover, these copolymers can also be used in order to improve the compatibility of polyether polyol and the hydrophobicity of polyether polyol.

（式中、Ｒ^１はジオールから水酸基を除いた残基であり、Ｒ^２はジカルボン酸から水酸基を除いた残基であり、ｎは正の整数、好ましくは２〜５０の整数である） (Iii) The polyester polyol can be obtained, for example, by dehydration condensation of a dicarboxylic acid and a diol, or an ester exchange reaction between an esterified product of a lower alcohol of a dicarboxylic acid and a diol, for example, represented by the following general formula (3) Things.

(In the formula, R ¹ is a residue obtained by removing a hydroxyl group from a diol, R ² is a residue obtained by removing a hydroxyl group from a dicarboxylic acid, and n is a positive integer, preferably an integer of 2 to 50)

  Specific examples of the diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5 -Pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9-nonane Diol, 2-methyl-1,8-octanediol, 1,10-decamethylene glycol, 1,2-tetradecanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, 1,3- Cyclohexanedimethanol, 3-xylylene glycol, 1,4-xylylene glycol, diethylene glycol Call, triethylene glycol, dipropylene glycol, and the like.

  Specific examples of the dicarboxylic acid include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, brassylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, Endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, chlorendic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalene Examples include dicarboxylic acids.

（式中、Ｒ^１はヒドロキシアルカン酸から水酸基及びカルボキシル基を除いた残基であり、Ｒ^２はジオールから水酸基を除いた残基であり、ｎは正の整数、好ましくは２〜５０の整数である） Examples of the (iv) polylactone polyol include those represented by the following general formula (4) obtained by ring-opening polymerization of a diol and a lactone compound, or a condensation reaction of a diol and a hydroxyalkanoic acid. It is done.

(In the formula, R ¹ is a residue obtained by removing a hydroxyl group and a carboxyl group from hydroxyalkanoic acid, R ² is a residue obtained by removing a hydroxyl group from diol, and n is a positive integer, preferably an integer of 2 to 50. Is)

  Specific examples of the diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5 -Pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9-nonane Diol, 2-methyl-1,8-octanediol, 1,10-decamethylene glycol, 1,2-tetradecanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, 1,3- Cyclohexanedimethanol, 3-xylylene glycol, 1,4-xylylene glycol, diethylene glycol Call, triethylene glycol, di Propylene glycol and the like.

  Specific examples of the lactone compound include ε-caprolactone and γ-butyrolactone, and specific examples of the hydroxyalkanoic acid include 3-hydroxybutanoic acid, 4-hydroxypentanoic acid, 5-hydroxy Hexanoic acid and the like are exemplified.

  (V) Examples of the polybutadiene polyol include diols obtained by polymerizing butadiene and isoprene by anionic polymerization and introducing hydroxyl groups at both ends by terminal treatment, diols obtained by hydrogen reduction of these double bonds, and the like. Can be mentioned.

  Specifically, as polybutadiene polyol, hydroxylated polyptadiene mainly having 1,4-repeating units (for example, Poly bd R-45HT, Poly bd R-15HT (trade name, manufactured by Idemitsu Kosan Co., Ltd.)) ), Hydroxylated hydrogenated polyptadiene (for example, polytail H, polytail HA (trade name, manufactured by Mitsubishi Chemical Corporation), GI-1000, GI-2000, GI-3000 (all trade names, manufactured by Nippon Soda Co., Ltd.) ), Etc.), hydroxylated polybutadiene having mainly 1,2-repeating units (for example, G-1000, G-2000, G-3000 (named above, trade name, manufactured by Nippon Soda Co., Ltd.)), hydroxylated polyisoprene. (For example, Poly IP (trade name, manufactured by Idemitsu Kosan Co., Ltd.)), hydroxylated hydrogenated polyisoprene (for example, Epol (Idemitsu) Production Co., Ltd. trade name), etc.) and the like.

  (Vi) Examples of the polyol having no oxygen atom other than oxygen atoms in the hydroxyl group and having 18 to 72 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8- Octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,10-decamethylene glycol, 1,2-tetradecane Diol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, 1,3-cyclohexane dimethyl Nord, 1,3-xylylene glycol, 1,4-xylylene glycol, diethylene glycol, triethylene glycol, or a molecular weight of 300 or less diol and dipropylene glycol. These polyol compounds may be added with (meth) acrylic acid for the purpose of imparting radical polymerizability or cationic polymerizability.

  (D) A polyol compound can be used individually by 1 type or in combination of 2 or more types. The (d) polyol compound preferably has a number average molecular weight of 250 to 50,000.

  The (e) monohydroxy compound is used for the purpose of imparting radical or cationic polymerizability to the (A) urethane resin or for eliminating the influence of the residue of the terminal isocyanate group.

  Monohydroxy compounds used for the purpose of imparting radical polymerizability include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 1,4-cyclohexanedi. Methanol mono (meth) acrylate, caprolactone or alkylene oxide adduct of each mono (meth) acrylate, glycerin di (meth) acrylate, trimethylol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta ( Examples include meth) acrylate, ditrimethylolpropane tri (meth) acrylate, allyl alcohol, allyloxyethanol, and hydroxyalkyl (meth) acrylamide. Among these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) Acrylate and hydroxyalkyl (meth) acrylamide are preferred.

  As monohydroxy compounds used for the purpose of eliminating the influence of the residue of the terminal isocyanate group, in addition to the above monohydroxy compounds, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec- Examples include butanol, t-butanol, amyl alcohol, hexyl alcohol, octyl alcohol and the like.

  (E) As the monohydroxy compound, glycolic acid having a carboxyl group, hydroxybivalic acid and the like are used.

  (E) Among the monohydroxy compounds, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,4- Cyclohexanedimethanol mono (meth) acrylate and hydroxyalkyl (meth) acrylamide are preferred. (E) Monohydroxy compounds can be used singly or in combination of two or more.

  (F) The epoxy acrylate compound is obtained by esterifying (meth) acrylic acid to an epoxy resin and modifying the acrylic resin, or by adding an acid anhydride to the epoxy acrylate in order to improve alkali developability. And carboxyl group-containing epoxy acrylate oligomers.

  The urethane resin soluble in the dilute alkali solution of the component (A) used in the present invention preferably has a number average molecular weight of 1,000 to 100,000, more preferably 3,000 to 50,000. preferable. Here, the number average molecular weight of the urethane resin is a polystyrene-converted value measured by gel permeation chromatography (GPC). If the number average molecular weight is less than 1,000, the elongation, flexibility, and strength of the cured film may be impaired. If the number average molecular weight exceeds 100,000, the solubility in a solvent is reduced and the film is dissolved. However, since the viscosity becomes too high, there is a possibility that restrictions on the use surface become large.

  The urethane resin soluble in the dilute alkali solution of component (A) preferably has an acid value of 5 to 120 mgKOH / g, more preferably 10 to 100 mgKOH / g. When the acid value is less than 5 mgKOH / g, the alkali solubility is lowered and alkali developability becomes difficult. When the acid value exceeds 120 mgKOH / g, when used as an alkali development type photoresist, the film loss during development increases. Long-term insulation reliability may be significantly reduced.

  Furthermore, the urethane resin soluble in the dilute alkali solution of component (A) preferably has a double bond equivalent of 100 to 2,000 g / eq, more preferably 300 to 1,800 g / eq. When the double bond equivalent is less than 100 g / eq, there are too many reaction points and the flexibility of the cured film is reduced. When it exceeds 2,000 g / eq, there are too few reaction points and the heat resistance of the cured film, Chemical resistance and the like may be significantly reduced.

  The urethane resin soluble in the dilute alkaline solution of the component (A) is prepared by using a suitable organic solvent in the presence or absence of a known urethanization catalyst such as dibutyltin dilaurate and using the above-mentioned (a) poly Synthesis by reacting an isocyanate compound, a polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, (d) a polyol compound, (e) a monohydroxy compound, and (f) an epoxy acrylate as necessary. can do. In addition, when the reaction is carried out under a non-catalyst, the physical property value of the final cured film, that is, the physical property value in actual use, is improved as compared with the case where the reaction is performed using a catalyst.

  Although the order in which the raw materials are charged is not particularly limited, usually, (b) a polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, and (d) a polyol compound are charged first and used as a solvent. After being dissolved, (a) a polyisocyanate compound is added dropwise at 20 to 150 ° C., preferably 60 to 120 ° C. Then, these are made to react at 30-160 degreeC, Preferably it is 50-130 degreeC. When the reaction is almost completed, (e) the monohydroxy compound is added dropwise at 20 to 150 ° C., preferably 60 to 120 ° C., and then held at the same temperature to complete the reaction. In addition, when using (f) epoxy acrylate compound, it charges first with the polyol compound etc. which have (b) bisphenol skeleton.

  The charge molar ratio of each raw material is adjusted according to the molecular weight, acid value, double bond equivalent, etc. of the target urethane resin, but the end of the urethane resin molecule is an isocyanate group ( The total number of b) polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, and (d) a polyol compound has a larger number than the number of isocyanate groups that the (a) polyisocyanate compound has. There is a need to. Specifically, the total of (a) the number of isocyanate groups possessed by the polyisocyanate compound, (b) a polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, and (d) a hydroxyl group possessed by the polyol compound. The ratio (a): [(b) + (c) + (d)] with the number is usually 1.0 to 1.3: 1, preferably 1.1 to 1.2: 1. To do. And an excess of this isocyanate group, usually 0.5 to 1.5 times, preferably 0.8 to 1.2 times the molar amount of (e) monohydroxy compound is used, and (b) The molar ratio (b) :( c) :( d) of the polyol compound having a bisphenol skeleton, (c) the dihydroxy compound having a carboxyl group, and (d) the polyol compound is usually 1: 1 to 4: 3 to 6, Preferably it is 1: 1-2: 4-5.

  Examples of the (B) component epoxy resin used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, and biphenol type epoxy resin. Resins, glycidyl ether type epoxy resins such as biphenyl type epoxy resins and naphthalene type epoxy resins; glycidyl amine type epoxy resins such as tetraglycidylaminodiphenylmethane and tetraglycidylaminodiphenyl sulfone; and alicyclic epoxy resins Can be mentioned. These epoxy resins can be used alone or in combination of two or more.

  The epoxy compound as the component (B) preferably has an epoxy equivalent of 150 g / eq to 800 g / eq. By making an epoxy equivalent into such a range, the photosensitive thermosetting resin composition excellent in characteristics, such as a flame retardance, can be obtained.

  Moreover, it is preferable that the compounding quantity of this epoxy compound of (B) component is 1-100 mass parts with respect to 100 mass parts of urethane resin of (A) component.

  It is preferable to use an epoxy resin curing agent in combination with the epoxy compound (B) in order to further improve the properties such as adhesion, chemical resistance and heat resistance. Examples of such epoxy resin curing agents include 2MZ, 2E4MZ, C11Z, C17Z, 2PZ, 1B2MZ, 2MZ-CN, 2E4MZ-CN, C11Z-CN, 2PZ-CN, 2PHZ-CN, 2MZ-CNS, 2E4MZ- Imidazole derivatives such as CNS, 2PZ-CNS, 2MZ-AZINE, 2E4MZ-AZINE, C11Z-AZINE, 2MA-OK, 2P4MHZ, 2PHZ, 2P4BHZ (trade names) manufactured by Shikoku Kasei Kogyo Co., Ltd .; acetoguanamine, benzoguanamine Polyamines such as guanamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, polybasic hydrazide; And / or epoxy adduct; amine complex of boron trifluoride; triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, 2,4-diamino-6-xylyl-S-triazine; Trimethylamine, triethanolamine, N, N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N-methylmorpholine, hexa (N-methyl) melamine, 2,4,6-tris (dimethylaminophenol), tetramethyl Tertiary amines such as guanidine and m-aminophenol; Polyphenols such as polyvinylphenol, polyvinylphenol bromide, phenol novolac, and alkylphenol novolac; tributylphosphine, triphenylphosphine, tris-2-cyanoethylphosphine Organic phosphines, phosphonium salts such as tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide and hexadecyltributylphosphonium chloride; quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride, the above polybasic Acid anhydride; diphenyliodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, Irgacure-261 (trade name, manufactured by Ciba Geigy), Optomer SP- 170 (trade name, manufactured by Asahi Denka Co., Ltd.); styrene-maleic anhydride resin; equimolar reaction product or tollet of phenyl isocyanate and dimethylamine Known as curing agents or accelerators for epoxy resins such as equimolar reaction products of organic polyisocyanates such as diisocyanate and isophorone diisocyanate and dimethylamine. These can be used individually by 1 type or in combination of 2 or more types.

  The compounding amount of the epoxy resin curing agent is preferably 0.01 to 25 parts by mass, more preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the urethane resin as the component (A). .

  As the organophosphorus compound of component (C) used in the present invention, a known organophosphorus compound used for imparting flame retardancy can be used, for example, a phosphorus-containing photopolymerizable monomer, biphenyl phosphate compound. And phosphazene compounds.

  The phosphorus-containing photopolymerizable monomer has a phosphorus atom that imparts flame retardancy in the molecule and a (meth) acryloyl group that is a radical polymerizable group, and the phosphorus atom is incorporated into the matrix of the cured product during photopolymerization. . Therefore, flame retardancy can be imparted without impairing flexibility and heat resistance.

（式中、Ｒは水素原子又はメチル基を示す。） As a phosphorus containing photopolymerizable monomer, what is represented by General formula (5) is mentioned, for example.

(In the formula, R represents a hydrogen atom or a methyl group.)

  And phosphorus compounds such as diethyl phosphite, di-n-propyl phosphite, dibutyl phosphite, dihexyl phosphite, diethyl phosphine oxide, di-n-propyl phosphine oxide, di-n-butyl phosphine oxide, dihexyl phosphine oxide Examples include phosphorus-containing (meth) acrylic compounds obtained by Michael addition reaction of (meth) acryloyl groups of (meth) acrylic compounds.

  The (meth) acrylic compound used as a raw material for the phosphorus-containing (meth) acrylic compound is preferably a polyfunctional (meth) acrylic compound having at least three (meth) acryloyl groups in one molecule from the viewpoint of curability. Used. Specific examples of such compounds include trimethylolpropane tri (meth) acrylate, tri (meth) acrylate of trimethylolpropane ethylene oxide adduct, tri (meth) acrylate of trimethylolpropane propylene oxide adduct, pentaerythritol tri (Meth) acrylate, pentaerythritol tetra (meth) acrylate, tetra (meth) acrylate of pentaerythritol ethylene oxide adduct, tetra (meth) acrylate of pentaerythritol propylene oxide adduct, dipentaerythritol hexa (meth) acrylate, tris ( 2-acryloyloxyethyl) isocyanurate and the like. From the viewpoint of flame retardancy and water resistance, trimethylolpropane (meth) acrylate, pentaerythritol tetra (meth) acrylate, tris (2-acryloyloxyethyl) isocyanurate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate are preferable. .

  The addition amount of the phosphorus compound to these polyfunctional (meth) acrylic compounds is suitably in the range of 0.1 to 0.7 equivalents, preferably 0.2 to 0, per 1 equivalent of the (meth) acryloyl group. .5 equivalents. If it is less than 0.1 equivalent, the flame retardancy is lowered, and if it exceeds 0.7 equivalent, the heat resistance is lowered.

  A general method can be used for the reaction of the polyfunctional (meth) acrylic compound and the phosphorus compound, and the mixture may be heated while being stirred and mixed in the reaction vessel. A catalyst is not particularly required. The reaction is performed while blowing dry air, the temperature is 50 to 180 ° C., preferably 100 to 130 ° C., and the reaction time is preferably 0.5 to 50 hours. If the temperature is too low, the reaction proceeds slowly and takes time. When the temperature is too high, a polymerization reaction of (meth) acrylic groups proceeds to produce a gelled product. A solvent may or may not be used during the reaction, but when used, a solvent inert to the reaction may be selected according to the solubility of the raw materials and the reaction temperature.

  A preferable phosphorus content of the phosphorus-containing (meth) acrylic compound thus obtained is 1 to 8% by mass, more preferably 2 to 6% by mass. If it is less than 1% by mass, sufficient flame retardancy will not be exhibited, and if it exceeds 8% by mass, the compatibility of other resin components may be reduced, or the viscosity may be too high and handling operability may be reduced.

（式中、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８及びＲ^９は、それぞれ同一又は異なって水素原子、一官能性の脂肪族基又は芳香族基を示す。） Examples of the biphenyl phosphite compound include compounds represented by the following general formula (6) or (7). The compound represented by the following general formula (6) or (7) is preferably used as the (C) organophosphorus compound because it has good stability and is excellent in the effect of imparting flame retardancy.

(Wherein R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same or different and each represents a hydrogen atom, a monofunctional aliphatic group or an aromatic group. .)

As the substituents R ^{2 to} R ⁹ , a hydrogen atom, a methyl group, an ethyl group, and a phenyl group are preferable, a hydrogen atom and a phenyl group are more preferable, and a hydrogen atom is still more preferable. As a specific compound, for example, in the phosphorus compound represented by the general formula (2), 9,10-dihydro-9-oxa-10-phosphater in which all of the substituents R ^{2 to} R ⁹ are hydrogen atoms. Phenanthrene-10-oxide is mentioned. In addition, in the phosphorus compound represented by the general formula (3), 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphine in which the substituents R ^{2 to} R ⁹ are all hydrogen atoms. Phenanthrene-10-oxide is mentioned. These compounds are available as commercial products. For example, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide can be obtained from Sanko Co., Ltd. (trade name: HCA). .

（式中、Ｒ^１０及びＲ^１１は、それぞれ水素原子又はハロゲンを含まない１価の有機基であり、ｎは３〜１０の整数である。） Examples of the phosphazene compound include phosphazene oligomers represented by the following general formula (8) or (9).

(In the formula, R ¹⁰ and R ¹¹ are each a monovalent organic group not containing a hydrogen atom or halogen, and n is an integer of 3 to ^10. )

Preferred examples of the monovalent organic group for the substituents R ¹⁰ and R ¹¹ include a phenyl group, an alkyl group, an amino group, and an allyl group. Moreover, as a terminal group of General formula (8), a hydrogen atom, a hydroxyl group, an alkyl group, an alkoxyl group, an aryloxy group, a cyanate group etc. are mentioned.

  More preferable phosphazene compounds include phosphazene oligomers such as propoxy phosphazene oligomers, phenoxy phosphazene oligomers, cyanate phenyl phosphazene oligomers, and cyanophenoxy phosphazene oligomers.

  The organophosphorus compound of component (C) preferably has a melting point of 80 ° C. or higher from the viewpoint of heat resistance, moisture resistance, flame retardancy, chemical resistance, and the like. Moreover, the organic phosphorus compound of (C) component can be used individually by 1 type or in combination of 2 or more types. Furthermore, the compounding amount of the organophosphorus compound of component (C) is preferably 1 to 50 parts by mass, and 1 to 30 parts by mass with respect to 100 parts by mass of the urethane resin of component (A). More preferred.

  The photopolymerization initiator of component (D) used in the present invention is a known photopolymerization initiator such as an active radical generator or a photosensitizer that generates active radicals upon irradiation with active light such as ultraviolet rays.

  Examples of the active radical generator include benzoins such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1 Acetophenones such as dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, N, N-dimethylaminoacetophenone; Anthraquinones such as methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone, 2,4-dimethylthioxanthone, 2, Thioxanthones such as 4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; benzophenone, methyl benzophenone, 4,4′-dichlorobenzophenone 4,4'-bisdiethylaminobenzophenone, Michler's ketone, benzophenones such as 4-benzoyl-4'-methyldiphenyl sulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like. These can be used alone or in combination of two or more.

  As photosensitizers, tertiary amines such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine and the like Etc.

  (D) The photoinitiator of a component can be used individually by 1 type or in combination of 2 or more types. Moreover, it is preferable that the compounding quantity of the photoinitiator of (D) component is 1-50 mass parts with respect to 100 mass parts of urethane resin of (A) component.

  As the diluent for component (E), an organic solvent and / or other compounds having a photopolymerizable double bond are used. Examples of the organic solvent include ketones such as ethyl methyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, Glycol ethers such as dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate and carbitol acetate; ethanol, propanol, ethylene glycol and propylene Alcohols such as glycol; aliphatic hydrocarbons such as octane and decane; petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, solvent Petroleum solvents such as support can be given.

  In addition, as other compounds having a photopolymerizable double bond, as a compound having one (meth) acryloyl group, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n- Propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, hexyl (meth) acrylate, octel (meth) acrylate 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylic Acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid 3-hydroxypropyl, (meth) -2-hydroxybutyl acrylate, and a mono (meth) acrylates such as (meth) -2-hydroxyphenyl acrylate.

  Further, as a compound having two or more (meth) acryloyl groups, (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-acryloylmorpholine; ethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane di (meth) Polyfunctional (meth) acrylates such as acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol penta (meth) acrylate, bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol Nord F type epoxy resin, novolak type epoxy resin, phenol novolak type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, N-glycidyl type epoxy resin, bisphenol A novolak type epoxy resin, chelate type epoxy resin, glyoxal Type epoxy resin, amino group-containing epoxy resin, rubber-modified epoxy resin, dicyclopentadiene phenolic epoxy resin, silicone-modified epoxy resin, ε-cabrolactone-modified epoxy resin, and so-called epoxy with (meth) acrylic acid added (Meth) acrylate etc. are mentioned.

  In addition, monovinyl ethers such as n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether; vinyl acetate, vinyl propionate, Monovinyl esters such as vinyl butyrate and vinyl benzoate; divinyl esters such as divinyl adipate; N-vinylamides such as N-vinylpyrrolidone and N-methyl-N-vinylacetamide, styrene, 2,4-dimethyl-α -Methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 2,6-dimethylstyrene, 3,4-di Tyl styrene, 3,5-dimethyl styrene, 2,4,6-trimethyl styrene, 2,4,5-trimethyl styrene, pentameter styrene, o-ethyl styrene, m-ethyl styrene, p-ethyl styrene, o-chlorostyrene , M-chlorostyrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-hydroxystyrene, m-hydroxystyrene P-hydroxystyrene, 2-vinylbiphenyl, 3-vinylbiphenyl, 4-vinylbiphenyl, 1-vinylnaphthalene, 2-vinylnaphthalene, 4-vinyl-p-terphenyl, 1-vinylanthracene, α-methylstyrene, o -Isopropenyltoluene, m-isopropyl Phenyltoluene, p-isopropenyltoluene, 2,4-dimethyl-α-methylstyrene, 2,3-dimethyl-α-methylstyrene, 3,5-dimethyl-α-methylstyrene, p-isopropyl-α-methylstyrene, Examples thereof include styrene derivatives such as α-ethylstyrene and α-chlorostyrene.

  Further, as a compound having two or more vinyl groups, ethylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, cyclohexane dimethanol divinyl ether And polyfunctional vinyl ethers such as diethylene glycol divinyl ether, triethylene glycol divinyl ether, trimeterolpropane trivinyl ether, pentaerythritol tetravinyl ether, divinylbenzene, divinylbiphenyl and the like.

  Examples of the compound having one allyl group include allyl alcohol, ethylene glycol monoallyl ether, allylamine, allyl glycidyl ether, and allyl esters such as allyl acetate and allyl benzoate. Examples of the compound include diallylamine, diallyl 1,4-cyclohexanedicarboxylate, diallyl phthalate, diallyl terephthalate, diallyl isophthalate, and the like.

  The diluent of this (E) component can be used individually by 1 type or in combination of 2 or more types. Further, the blending amount of the diluent of component (E) is preferably 1 to 100 parts by mass, more preferably 10 to 80 parts by mass with respect to 100 parts by mass of the urethane resin of component (A). .

  The purpose of use of this diluent is, in the case of other compounds having a photopolymerizable double bond, to adjust the viscosity to a state where it is easy to apply by diluting the urethane resin of component (A) and to enhance the photopolymerizability. In the case of an organic solvent, the viscosity of the component (A) urethane resin is dissolved, diluted and adjusted to a state where it can be easily applied, and after being applied in liquid form, it is formed by drying. Accordingly, either a contact method or a non-contact exposure method in which the photomask is brought into contact with the coating film is selected according to the type of diluent used.

  In addition to the components described above, the photosensitive thermosetting resin composition of the present invention may further include barium sulfate, barium titanate, oxidation, for the purpose of improving properties such as adhesion and hardness. Known inorganic fillers such as silicon powder, finely divided silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica powder can be blended. It is preferable that the compounding quantity of an inorganic filler is 0-60 mass% with respect to the whole photosensitive thermosetting resin composition, and it is more preferable that it is 5-40 mass%.

  If necessary, colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, pyrogallol, phenothiazine Polymerization inhibitors such as asbestos, olben, benton, montmorillonite, etc., defoamers such as silicones, fluorines and polymers, leveling agents, imidazoles, thiazoles, triazoles and other silane couplings An additive such as an agent can be blended.

  Furthermore, copolymers of ethylenically unsaturated compounds such as acrylic esters, binder resins such as polyester resins synthesized from polyhydric alcohols and polybasic acid compounds, and photopolymerizable oligomers such as polyester (meth) acrylates Can be used as long as they do not affect various properties of the photosensitive thermosetting resin composition.

  The photosensitive thermosetting resin composition of the present invention is uniformly mixed with a three-roll mill after adding and blending other components as necessary in addition to the components (A) to (E). Can be manufactured.

  Moreover, the flexible printed wiring board of the present invention is a photosensitive thermosetting type of the present invention in the form of a varnish on a flexible printed wiring board in which a copper foil is bonded to one or both sides of a polyimide film with a heat roll to form a wiring pattern. A flexible copper-clad laminate is manufactured by the usual method of applying a resin composition and then heat-curing, and if necessary, drilling through-hole plating or stacking a coverlay with holes in place. It can be produced by the usual method of heat-press molding.

  Furthermore, a flexible printed wiring board with a reinforcing plate can be produced by an ordinary method of superimposing a reinforcing plate on the flexible printed wiring board via a thermosetting resin composition and then performing heat and pressure molding.

  In addition, the flexible printed wiring board of the present invention is overlaid with a flexible copper-clad laminate, etc. via a thermosetting resin composition, heated and pressed, formed through holes, plated through holes, and then predetermined. A multilayer flexible printed wiring board can be manufactured by the usual method of forming the circuit.

  Next, examples and comparative examples of the present invention will be described.

[Synthesis of urethane resin]
(Production Example 1)
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, (d) Plaxel CD CD210PL (polycarbonate diol; trade name, manufactured by Daicel Chemical Industries, Ltd.) 37.11 g as a polyol compound, (b) a polyol compound having a bisphenol skeleton BP-3P (trade name, manufactured by Sanyo Chemical Industries, Ltd.) 25.30 g, (c) 2,2-dimethylolpropionic acid 28.77 g as a dihydroxy compound having a carboxyl group, and diethylene glycol ethyl ether acetate 129. as a solvent. 68 g was charged and 2,2-dimethylolpropionic acid was dissolved at 90 ° C. (partially insoluble). The temperature of the reaction solution was lowered to 70 ° C., and 55.49 g of Takenate 600 (trade name, manufactured by Mitsui Polyurethane Co., Ltd.) was added dropwise as a polyisocyanate compound over 30 minutes using a dropping funnel. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 6 hours. When it was confirmed that (a) the polyisocyanate compound almost disappeared, 8.47 g of 2-hydroxyethyl acrylate was added dropwise as the monohydroxy compound. For 1.5 hours to obtain a urethane resin (A-1).

  The obtained urethane resin (A-1) had a number average molecular weight of 4500 and an acid value of solid content of 85.2 mgKOH / g.

(Production Example 2)
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, (d) 42.93 g of Plaxel CD CD210PL as a polyol compound, (b) 28.56 g of BP-3P as a polyol compound having a bisphenol skeleton, and (c) a carboxyl group. 26.83 g of 2,2-dimethylolpropionic acid as a dihydroxy compound having, and 126.38 g of diethylene glycol ethyl ether acetate as a solvent were dissolved, and 2,2-dimethylolpropionic acid was dissolved at 90 ° C. (partly insoluble) . The temperature of the reaction solution was lowered to 70 ° C., and 48.43 g of Takenate 700 (trade name, manufactured by Mitsui Polyurethane Co., Ltd.) was added dropwise as a polyisocyanate compound over 30 minutes using a dropping funnel. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 4 hours. (A) When it was confirmed that the polyisocyanate compound almost disappeared, (e) 7.94 g of 2-hydroxyethyl acrylate was added dropwise as the monohydroxy compound, and further 90 ° C. For 1.5 hours to obtain a urethane resin (A-2).

  The obtained urethane resin (A-2) had a number average molecular weight of 5770 and an acid value of solid content of 79.1 mgKOH / g.

(Production Example 3)
In a reaction vessel equipped with a stirrer, a thermometer and a condenser, (d) 91.85 g of Plaxel 210 (polycaprolactone diol; trade name, manufactured by Daicel Chemical Industries, Ltd.) as a polyol compound, (b) a polyol having a bisphenol skeleton BP-3P 28.56 g as a compound, (c) 2,2-dimethylolbutanoic acid 32.18 g as a dihydroxy compound having a carboxyl group, and diglyme 205.92 g as a solvent, and 2,2-dimethylol at 70 ° C. Butanoic acid was dissolved (partially insoluble), and 73.66 g of Takenate 600 was added dropwise as a polyisocyanate compound over 30 minutes using a dropping funnel. After completion of the dropwise addition, the mixture was reacted at 90 ° C. for 4 hours. When it was confirmed that (a) the polyisocyanate compound almost disappeared, 8.22 g of 2-hydroxyethyl acrylate was added dropwise as the monohydroxy compound. For 2 hours to obtain a urethane resin (A-3).

  The obtained urethane resin (A-3) had a number average molecular weight of 5770 and an acid value of solid content of 59.1 mgKOH / g.

(Production Example 4)
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, (d) Plaxel 210 91.85 g as a polyol compound, (b) BP-3P 28.56 g as a polyol compound having a bisphenol skeleton, (c) having a carboxyl group 2,2-dimethylolbutanoic acid 32.18 g as a dihydroxy compound and diglyme 205.92 g as a solvent were charged, and 2,2-dimethylolbutanoic acid was dissolved at 70 ° C. (partially insoluble). (A) 73.66 g of Takenate 700 was dropped as a polyisocyanate compound over 30 minutes. After completion of the dropwise addition, the mixture was reacted at 90 ° C. for 4 hours. When it was confirmed that (a) the polyisocyanate compound almost disappeared, 8.22 g of 2-hydroxyethyl acrylate was added dropwise as the monohydroxy compound. For 2 hours to obtain a urethane resin (A-4).

  The obtained urethane resin (A-4) had a number average molecular weight of 5850 and an acid value of solid content of 57.9 mgKOH / g.

(Production Example 5)
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, (d) T-4691 (polycarbonate diol; trade name, manufactured by Asahi Kasei Chemicals Corporation) as a polyol compound, (c) As a dihydroxy compound having a carboxyl group 28.77 g of 2,2-dimethylolpropionic acid and 129.68 g of diethylene glycol ethyl ether acetate as a solvent were charged, and 2,2-dimethylolpropionic acid was dissolved at 90 ° C. (partly insoluble). The temperature of the reaction liquid was lowered to 70 ° C., and 55.49 g of Takenate 600 as a polyisocyanate compound was dropped over 30 minutes with a dropping funnel. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 6 hours. When it was confirmed that (a) the polyisocyanate compound almost disappeared, 8.47 g of N-hydroxyethylacrylamide was added dropwise as the monohydroxy compound, and further 90 ° C. For 1.5 hours to obtain a urethane resin (R-1).

  The obtained urethane resin (R-1) had a number average molecular weight of 3490 and a solid acid value of 92.7 mgKOH / g.

(Production Example 6)
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, (d) T-4691 (polycarbonate diol; trade name, manufactured by Asahi Kasei Chemicals Corporation) as a polyol compound, (c) As a dihydroxy compound having a carboxyl group 28.77 g of 2,2-dimethylolpropionic acid and 129.68 g of diethylene glycol ethyl ether acetate as a solvent were charged, and 2,2-dimethylolpropionic acid was dissolved at 90 ° C. (partly insoluble). The temperature of the reaction solution was lowered to 70 ° C., and 55.49 g of Takenate 700 was added dropwise as a polyisocyanate compound over 30 minutes using a dropping funnel. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 6 hours. When it was confirmed that (a) the polyisocyanate compound almost disappeared, 8.47 g of N-hydroxyethylacrylamide was added dropwise as the monohydroxy compound, and further 90 ° C. For 1.5 hours to obtain a urethane resin (R-2).

  The obtained urethane resin (R-2) had a number average molecular weight of 3880 and an acid value of solid content of 49.5 mgKOH / g.

Example 1
50 parts by mass of urethane resin (A-1) and 50 parts by mass of urethane resin (A-2), 20 parts by mass of Kayrad DPHA (manufactured by Nippon Kayaku Co., Ltd., trade name) as a diluent, SPEEDCURE TPO as a photopolymerization initiator (Nippon Shibel Hegner Co., Ltd., trade name; written as photopolymerization initiator (D-1)) 7 parts by mass, Irgacure 184 (made by Ciba Specialty Chemicals, trade name: written as photopolymerization initiator (D-2)) 3 parts by weight, 1 part by weight of ethyl Michler's ketone as a photopolymerization accelerator, 15 parts by weight of Epicoat YX4000 (trade name: Epoxy equivalent 180) manufactured by Japan Epoxy Resin Co., Ltd., which is a biphenyl type epoxy resin as an epoxy resin, 2 parts by mass of 2E4MZ (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd.) of imidazole-based curing catalyst and 2 parts by mass of melamine, As compound, FRM-1000 (Nippon Kayaku Co., Ltd. trade name; expressed as organophosphorus compound (C-1)) 5 parts by mass and phenoxyphosphazene oligomer EP-100 (Fushimi Pharmaceutical Co., Ltd. trade name; organophosphorus compound ( C-2)) 10 parts by weight, B-30 of barium sulfate (trade name, manufactured by Sakai Chemical Industry Co., Ltd.) 10 parts by weight, 2 parts by weight of phthalocyanine blue, Aerosil R972 (produced by Nippon Aerosil Co., Ltd.) Product name) 5 parts by mass were blended and kneaded by a three roll mill to produce a photosensitive thermosetting resin composition.

(Example 2)
Photosensitive thermosetting resin composition by the same composition and operation as in Example 1 except that the blending amounts of the urethane resin (A-1) and the urethane resin (A-2) were changed to 80 parts by mass and 20 parts by mass, respectively. The thing was manufactured.

(Example 3)
Photosensitive thermosetting resin composition by the same composition and operation as in Example 1 except that the blending amounts of the urethane resin (A-1) and the urethane resin (A-2) were changed to 20 parts by mass and 80 parts by mass, respectively. The thing was manufactured.

Example 4
Instead of using 50 parts by mass of urethane resin (A-1) and 50 parts by mass of urethane resin (A-2), 50 parts by mass of urethane resin (A-3) and 50 parts by mass of urethane resin (A-4) were used. Produced a photosensitive thermosetting resin composition by the same composition and operation as in Example 12.

(Example 5)
A photosensitive thermosetting resin composition was produced by the same composition and operation as in Example 1 except that the urethane resin (A-4) was used instead of the urethane resin (A-2).

(Example 6)
Instead of FRM-1000 as an organophosphorus compound, 162 parts by mass (0.75 mol) of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) in 338 parts by mass (10 mol) of trimethylolpropane trimethacrylate ) And using a phosphorus-containing light quantity compatible monomer (represented as organophosphorus compound (C-3)) obtained by reacting at 130 ° C. for 15 hours while blowing air, and changing the blending amount to 8 parts by mass. Except for the above, a photosensitive thermosetting resin composition was produced by the same composition and operation as in Example 1.

(Comparative Example 1)
By replacing the 50 parts by mass of the urethane resin (A-1) and 50 parts by mass of the urethane resin (A-2) with the same composition and operation as in Example 1 except that 100 parts by mass of the urethane resin (R-1) was used. A photosensitive thermosetting resin composition was produced.

(Comparative Example 2)
Instead of using 50 parts by mass of urethane resin (A-1) and 50 parts by mass of urethane resin (A-2), 50 parts by mass of urethane resin (R-1) and 50 parts by mass of urethane resin (R-2) were used. Produced a photosensitive thermosetting resin composition by the same composition and operation as in Example 1.

(Comparative Example 3)
A photosensitive thermosetting resin composition was produced by the same composition and operation as in Example 1 except that the organophosphorus compound was not blended.

[Evaluation of Photosensitive Thermosetting Resin Composition]
The photosensitive thermosetting resin compositions obtained in the above examples and comparative examples are each patterned by a screen printer so as to have a thickness of 20 to 30 μm using a 150 mesh polyester screen. The whole surface was applied to a copper-clad polyimide film substrate (copper thickness 18 μm / polyimide film thickness 25 μm) or 12.5 μm-thick polyimide film, and the coating film was dried with a hot air dryer at 80 ° C. for 30 minutes. Next, the negative film of the resist pattern was brought into contact with the coating film and irradiated with ultraviolet rays using an ultraviolet irradiation exposure apparatus (exposure amount 400 mJ / cm ² ). Thereafter, the film is developed by spraying with an aqueous solution of 1% by weight of sodium carbonate at about 0.1 MPa for 1 minute, dissolving and removing the unexposed portion, and further thermally cured under conditions of 150 ° C. × 60 minutes. Formed. In addition, about what formed the coating film on the whole surface of the polyimide film, the coating film whole surface was irradiated with the ultraviolet-ray, and also was thermosetted.

  The test substrate or test film thus obtained has the following flame retardancy, insulation resistance, adhesion, low warpage, flexibility, resolution, solder heat resistance, chemical resistance and folding resistance. Measurements and evaluations were made based on the methods and criteria shown in. These results are shown in Table 1 together with the composition of the photosensitive thermosetting resin composition.

[Flame retardance]
The test was conducted according to the UL94 flame retardant test.
[Insulation resistance]
The test was conducted according to IEC-PB112.
[Adhesion]
A peel test using a cellophane tape was performed on a test piece cross-cut to 100 mm according to JIS D 0202 on the surface of the cured film of the test substrate, and the number of peeled pieces was examined.
[Low warpage]
A test piece having a diameter of 50 mm was cut out from the test film and placed with the cured film surface facing upward, and the height of the warp of the film was measured.
[Flexibility]
The test film was repeatedly bent at 180 ° with the cured film surface facing outward to measure the number of times the cured film was whitened and cracked.
[Resolution]
Using an electron microscope, the opening state of the via hole when the coating film was alkali-developed on the substrate was confirmed.
[Solder heat resistance]
According to JIS C 6481, the test piece was floated on a 300 ° C. solder bath for 1 minute, observed for the presence or absence of swelling, and evaluated according to the following criteria.
◎… No swelling, ○… Partial swelling, ×… All swelling [chemical resistance]
About each of 10% sulfuric acid, 10% sodium hydroxide aqueous solution, isopropyl alcohol, methanol, and methyl ethyl ketone, the test piece was immersed for 30 minutes at room temperature, and the external appearance was confirmed.
○: No change in appearance, ×: Change in appearance [Folding resistance]
According to JIS C 6471, the number of times until a crack of the cured film occurred at R = 0.38 mm and a load of 4.9 N was measured with an MIT folding resistance tester.

  From these results, the photosensitive thermosetting resin composition of the present invention gave good results in all the evaluated properties.

Claims (14)

(A) at least (a) a polyisocyanate compound, (b) a polyol compound having a bisphenol skeleton, (c) a dihydroxy compound having a carboxyl group, (d) a polyol compound other than components (b) and (c), and (e A urethane resin soluble in a dilute alkali solution having a (meth) acryloyl group and a carboxyl group in one molecule, produced from a monohydroxy compound as a raw material;
(B) an epoxy resin;
(C) an organophosphorus compound;
(D) a photopolymerization initiator;
(E) a diluent;
A photosensitive thermosetting resin composition comprising:   For 100 parts by mass of the urethane resin of the component (A), 1 to 100 parts by mass of the epoxy resin of the component (B), 1 to 50 parts by mass of the organophosphorus compound of the component (C), 2. The photosensitive thermosetting resin composition according to claim 1, comprising 1 to 50 parts by weight of a photopolymerization initiator and 1 to 100 parts by weight of a diluent for the component (E).   3. The photosensitive thermosetting resin composition according to claim 1, wherein an epoxy acrylate compound (f) is further used as a raw material for the urethane resin as the component (A).   The component (a) contains a polyisocyanate compound having an alicyclic structure having 6 to 30 carbon atoms other than carbon atoms in the isocyanate group. The photosensitive thermosetting resin composition according to Item.   The polyisocyanate compound having an alicyclic structure is composed of 1,4-cyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), hydrogenated 1,3-xylylene diisocyanate and hydrogenated 1,4-xylylene diisocyanate. The photosensitive thermosetting resin composition according to claim 4, wherein the photosensitive thermosetting resin composition is at least one selected from the group consisting of:   The said (a) component contains the polyisocyanate compound which has 6-30 carbon atoms other than the carbon atom in an isocyanate group, and has an aliphatic structure characterized by the above-mentioned. The photosensitive thermosetting resin composition described.   The photosensitive thermosetting resin according to claim 6, wherein the polyisocyanate compound having an aliphatic structure is at least one selected from the group consisting of hexamethylene diisocyanate, trimethylhexane diisocyanate, and methylpentane diisocyanate. Composition.   The component (b) is at least one selected from the group consisting of a bisphenol A alkylene oxide adduct, a bisphenol F alkylene oxide adduct, and a bisphenol S alkylene oxide adduct. The photosensitive thermosetting resin composition according to claim 1.   The photosensitive thermosetting type according to any one of claims 1 to 8, wherein the component (c) is 2,2-dimethylolpropionic acid and / or 2,2-dimethylolbutanoic acid. Resin composition.   The component (d) is a polyol (polycarbonate polyol, polyether polyol, polyester polyol, polylactone polyol, polybutadiene polyol, or polyol having no oxygen atom other than oxygen atoms in the hydroxyl group and having 18 to 72 carbon atoms) However, the photosensitive thermosetting resin composition according to any one of claims 1 to 9, wherein the photosensitive thermosetting resin composition is at least one selected from the group consisting of (excluding polybutadiene polyol).   The component (e) is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,4-cyclohexanedimethanol mono The photosensitive thermosetting resin composition according to any one of claims 1 to 10, wherein the photosensitive thermosetting resin composition is at least one selected from the group consisting of (meth) acrylates and hydroxyalkyl (meth) acrylamides.   The urethane resin as the component (A) is a urethane resin having a number average molecular weight of 1,000 to 100,000 and an acid value of 5 to 100 mgKOH / g. Photosensitive thermosetting resin composition.   The photosensitive thermosetting resin composition according to any one of claims 1 to 12, wherein the urethane resin as the component (A) is a urethane resin having a double bond equivalent of 100 to 2,000 g / eq. object. A flexible printed wiring board comprising a copper layer on a polyimide layer directly or via an adhesive layer,
A flexible printed wiring board comprising a resin layer formed of the photosensitive thermosetting resin composition according to claim 1 on a surface of the copper layer.