JP5680331B2 - Photosensitive resin composition and flexible printed wiring board using the same - Google Patents

Description

  The present invention has halogen-free flame retardancy, and does not generate harmful gases such as hydrogen bromide or dioxins during combustion, and is excellent in heat resistance, flex resistance, adhesion, and flame retardancy. The present invention relates to an alkali development type photosensitive resin composition and a flexible printed wiring board using the same.

  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, when incinerating resins using brominated flame retardants so far, toxic gases such as dioxins are generated, and the environmental burden during incineration and disposal is large.

  Furthermore, in recent years, organophosphorous flame retardants have been used in place of brominated flame retardants in response to environmental problems. However, this organophosphorous flame retardant is not so excellent in flame retardant properties. When adding equivalent flame retardancy to a resin composition, the amount added is higher than that of brominated flame retardant. Therefore, there are problems such as deterioration of characteristics and bleeding of the composition.

  In order to improve such characteristics, it has been studied to improve flame retardancy by using resin-based materials using a compound having a specific structure, but those having sufficient characteristics can still be obtained. (For example, see Patent Documents 2 and 3).

JP-A-9-54434 JP 2001-72835 A JP 2007-147720 A

Techniques using inorganic flame retardants that do not have the above disadvantages have also been studied. Among them, aluminum hydroxide (Al (OH) ₃ ) is particularly rich in structural water and has excellent flame retardant effects as well as acid resistance. It is widely used because of its excellent properties and alkali resistance and is advantageous in terms of cost. Regarding the flame retardant properties of this aluminum hydroxide, it is known that dehydration starts gradually from about 200 ° C. and dehydrates all at once from around 230 ° C. to 250 ° C. However, when this is used for a printed circuit board, the ambient temperature when soldering on the electric board is around 230 ° C., so that the aluminum hydroxide is dehydrated at that time, which reduces the yield of the electric board. was there.

Under such circumstances, it is conceivable to use another inorganic flame retardant having a high dehydration temperature. However, for example, boehmite (AlO (OH)) has a dehydration peak around 500 ° C., which is advantageous in that respect, but has a problem that the amount of dehydration is small due to a small amount of structural water. Further, magnesium hydroxide (Mg (OH) ₂ ) has a peak dehydration temperature as high as about 380 ° C., but has strong alkalinity and easily deteriorates the synthetic resin. In addition to being unable to be used in an environment where it comes into contact with an acid, there is a drawback that it is easily dissolved when etching with an acid in electronic device parts. Also, in high humidity conditions, magnesium hydroxide absorbs carbon dioxide in the air and turns into basic carbonate, causing a whitening phenomenon on the resin surface containing magnesium hydroxide, a flame retardant, which in turn affects the product characteristics. It has the disadvantage of giving.

  Accordingly, the 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 the resin composition, and to provide plasticity, resolution, solder heat resistance, moisture resistance, and chemical resistance. It is an object of the present invention to provide an alkali-developable photosensitive resin composition capable of forming an excellent film and the like, and a flexible printed wiring board using the same.

  As a result of diligent studies to solve the above-mentioned problems, the present inventors have found that, in an alkali development type photosensitive thermosetting resin composition, in place of a halogen-containing compound, heat-treated aluminum hydroxide is used. The present invention has been completed by finding that the above-mentioned problems can be solved by using a phosphorous compound in combination with the present invention.

  That is, the photosensitive resin composition of the present invention has (A) a (meth) acryloyl group and a carboxyl group in one molecule, a resin component soluble in a dilute alkaline solution, and (B) an epoxy group. It contains a thermosetting component, (C) heat-resistant aluminum hydroxide, (D) a phosphorus flame retardant, (E) a photopolymerization initiator, and (F) a diluent. is there.

  Moreover, the flexible printed wiring board of the present invention is a flexible printed wiring board composed of a polyimide layer and a copper layer, or a polyimide layer, an adhesive layer and a copper layer. It has the resin layer formed with the photosensitive resin composition of this.

  The photosensitive resin composition of the present invention has a high level of flame retardancy without using brominated epoxy resin or halogen-based flame retardant, plasticity, resolution, solder heat resistance, moisture resistance, chemical resistance It is possible to form an excellent film.

  In addition, since the flexible printed wiring board of the present invention uses the photosensitive resin composition having the above-described excellent characteristics, such as hydrogen bromide and dioxins which have been a problem at the time of combustion of the resin composition. Since no toxic gas is generated, the environmental load can be reduced.

  Hereinafter, the present invention will be described in detail.

  The resin component soluble in the diluted alkaline solution (A) used in the present invention has a (meth) acryloyl group and a carboxyl group in one molecule, and is soluble in the diluted alkaline solution. In this component, the (meth) acryloyl group in the molecule is polymerized by radicals generated from the photopolymerization initiator (E) described later by irradiation with active energy rays such as ultraviolet rays. As a result, the resin composition is It has an insolubilizing function.

  Examples of the resin component soluble in the (A) dilute alkali solution include, for example, epoxy acrylate obtained by esterifying (meth) acrylic acid with an epoxy resin to modify acrylic, and adding an acid anhydride. A compound (for example, an epoxy acrylate oligomer) is mentioned.

  As an epoxy resin as a raw material of the epoxy acrylate compound, a known epoxy resin can be used, and a general bisphenol type epoxy resin or the like can be preferably used. Moreover, as (meth) acrylic acid as a raw material, acrylic acid, methacrylic acid, and a mixture thereof can be used. Furthermore, as the acid anhydride as a raw material, phthalic anhydride, succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, itaconic anhydride, Methyl endomethylenetetrahydrophthalic anhydride or the like can be used, and among them, succinic anhydride or phthalic anhydride is particularly preferable.

  In addition, (A) a resin component soluble in a dilute alkaline solution includes a polyol compound, a polybasic acid anhydride having two anhydrides in the molecule, and a (meth) acryl having one epoxy group in the molecule. It is also possible to use a carboxyl group-containing urethane compound (for example, a carboxyl group-containing urethane oligomer) obtained by reacting with an acid.

  The resin component soluble in the (A) dilute alkaline solution of the present invention preferably has an acid value in the range of 50 to 200 mg KOH / g, and (A) the acid of the resin component as a component soluble in the dilute alkaline solution If the value is less than 50 mgKOH / g, alkali solubility is lowered and alkali development becomes difficult. If it exceeds 200 mgKOH / g, the film thickness during development increases when used as an alkali development type photoresist. May be significantly reduced. The acid value of the resin component soluble in the (A) dilute alkali solution is more preferably in the range of 80 to 150 mgKOH / g.

  The blending amount of the resin component soluble in the (A) dilute alkali solution is preferably 20 to 70% by mass with respect to the entire photosensitive resin composition of the present invention.

  The thermosetting component having an epoxy group (B) used in the present invention can be used without particular limitation as long as it is a compound having one or more epoxy groups in the molecule, that is, generally referred to as an epoxy resin. For example, known epoxy resins such as glycidyl ethers typified by bisphenol A, bisphenol F, bisphenol S, phenol novolac, orthocresol novolak, glycidylaminodiphenylmethane and tetraglycidylaminodiphenylsulfone are known. Can be mentioned. At this time, it is preferable that the epoxy equivalent of (B) thermosetting component is 130g / eq-1500g / eq. By setting the epoxy equivalent in such a range, a photosensitive resin composition having more excellent characteristics such as flame retardancy can be obtained.

  These thermosetting components may be used individually by 1 type, and 2 or more types may be mixed and used for them. Moreover, as a compounding quantity of this (B) thermosetting component which has an epoxy group, it is preferable that it is 1-100 mass parts with respect to 100 mass parts of (A) resin components.

  Moreover, it is preferable to use an epoxy resin curing agent in combination with the thermosetting component having an epoxy group (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 (above, trade names manufactured by Shikoku Kasei Kogyo Co., Ltd.); acetoguanamine, benzoguanamine, etc. Guanamines, diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, polybasic hydrazides and the like; their organic acid salts And / or epoxy adducts; amine complexes 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-cyanoethylphosphite Organic phosphines such as tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide, phosphonium salts such as hexadecyltributylphosphonium chloride; quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride, Basic acid anhydride; diphenyliodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, Irgacure-261 (trade name, manufactured by Ciba-Geigy), optomer Photo-cationic polymerization catalyst such as SP-170 (manufactured by Asahi Denka Co., Ltd., trade name); styrene-maleic anhydride resin; equimolar reaction product of phenyl isocyanate and dimethylamine, Known and commonly used curing agents or curing accelerators such as an equimolar reaction product of organic polyisocyanate such as tolylene diisocyanate and isophorone diisocyanate and dimethylamine can be used alone or in admixture of two or more.

  Here, the compounding amount of the epoxy resin curing agent is preferably 0.01 to 25 parts by mass, and 0.1 to 15 parts by mass with respect to 100 parts by mass of the resin component (A) soluble in the dilute alkali solution. It is particularly preferred that

  The heat-resistant aluminum hydroxide (C) used in the present invention is suppressed to boehmite even by hydrothermal treatment in a high temperature range, or pressurization and heating in a steam atmosphere, and the dehydration temperature while maintaining a sufficient dehydration amount. In particular, the aluminum hydroxide has a 1% by mass dehydration temperature of 255 ° C. or higher and a total dehydration amount of 30% by mass or higher. Here, the 1% by mass dehydration temperature refers to the temperature at which 1% by mass of structural water dehydrates relative to the total mass of aluminum hydroxide in the resin, and the total dehydration amount refers to the water in the resin. When all the structural water contained in aluminum oxide is dehydrated, the amount of structural water dehydrated with respect to the total mass of aluminum hydroxide in the resin (before dehydration) is expressed in mass%.

  Here, (C) heat-resistant aluminum hydroxide is prepared by mixing aluminum hydroxide with a reaction retarder that delays boehmite formation, and pressurizing and heating the mixture in a hydrothermal treatment or steam atmosphere Can be manufactured.

  Here, the hydrothermal treatment refers to adding water that exceeds the saturated water vapor amount to a mixture of aluminum hydroxide and a reaction retardant, and performing a heat treatment using a pressure vessel such as an autoclave (hereinafter referred to as a wet treatment). Is). Also, the treatment by pressurization and heating in a steam atmosphere is to use a pressure vessel such as an autoclave without adding water to the mixture of aluminum hydroxide and reaction retarder or by adding water below the saturated water vapor amount. Pressure and processing (hereinafter, sometimes referred to as dry processing). The heat-resistant aluminum hydroxide of the present invention can be produced by heating in a pressure vessel without adding water to a raw material in which aluminum hydroxide and a reaction retarder that delays boehmite formation are mixed. Heating in a pressure vessel without adding water to the raw material means that heat treatment is performed without generating water vapor, except that water is not added to the raw material and a part of the raw aluminum hydroxide is dehydrated and vaporized by heating. (Hereinafter sometimes referred to as dry processing). In addition to the vapor pressure due to the water vapor, compressed air may be sent from the outside into the pressure vessel for pressurization.

  A reaction retarder delays the boehmite conversion of aluminum hydroxide in wet or dry processing, and has a high thermal history (a high processing temperature and a long processing time at which aluminum hydroxide becomes 100% boehmite). However, it is a substance that makes it possible to produce aluminum hydroxide that has a low boehmite conversion rate or does not undergo boehmite conversion. Generally, when aluminum hydroxide is wet-treated or dry-treated, a relatively low thermal history (usually 160 ° C / 3 hours for dry-treatment, 170 ° C / 10 hours for wet-treatment (water / aluminum hydroxide mass ratio = 3), Similarly, in the case of adding sodium hydroxide by wet treatment (water / aluminum hydroxide mass ratio = 3) (170 ° C./3 hours for sodium hydroxide / aluminum hydroxide molar ratio = 1/12))), almost 100% It becomes boehmite. However, when the reaction retarder in the present invention is used, the boehmite conversion rate of aluminum hydroxide can be sufficiently suppressed even if wet treatment is performed at a high heat history, for example, 215 ° C. for 10 hours or dry treatment. The dehydration temperature can be significantly increased.

  Regarding the mechanism for increasing the dehydration temperature, (1) the aluminum hydroxide crystals are rearranged by a high thermal history, and the Al—O bond is strengthened, and (2) the trace amount of aluminum hydroxide is reduced by the high thermal history. Dissolves and precipitates, the surface of aluminum hydroxide becomes smooth, and the number of dehydration start points decreases (dehydration mechanism starts from cracks (defects) on the surface of aluminum hydroxide, and dehydration further increases cracks. The subsequent dehydration occurs in a chain).

  The treatment temperature in wet treatment or dry treatment can be 170 ° C. or higher and 300 ° C. or lower, preferably 200 ° C. or higher and 250 ° C. or lower. If the treatment temperature is low, the dehydration temperature cannot be sufficiently increased, and the higher the treatment temperature, the higher the heat history. This is preferable, but if the treatment temperature is too high, the amount of reaction retarder that suppresses the reaction increases because the boehmite formation tends to proceed. In addition, the pressure during processing becomes very high and the autoclave device becomes impractical. The treatment time in the wet treatment or the dry treatment can be 1 hour or more and 24 hours or less, preferably 5 hours or more and 10 hours or less. If the treatment time is short, the dehydration temperature cannot be sufficiently increased, and the longer the treatment time, the higher the heat history is preferable.However, if the treatment time is too long, the amount of the reaction retarding agent that suppresses the reaction is increased because the boehmite formation tends to proceed. Will have to.

  The reaction retardant is not particularly limited as long as it falls within the above definition, but sulfuric acid, nitric acid, phosphoric acid, tetrafluoroboric acid, diammonium hydrogen phosphate, sodium dihydrogen bisphosphate monohydrate, phosphorus Inorganic acids such as sodium dihydrogen and potassium metaphosphate or salts thereof, acetic acid, succinic acid, organic acids such as lactic acid, fumaric acid and tartaric acid or salts thereof, silica, silane coupling agent, white carbon, hexafluorosilicic acid, Examples thereof include silicon compounds such as sodium hexafluorosilicate, potassium silicofluoride, aluminum fluoride, fly ash, diatomaceous earth, and siloxane, and fluorine compounds. The fluorine compound means a compound that includes a wide range of compounds containing elemental fluorine. The above-mentioned tetrafluoroboric acid is an inorganic acid as well as a fluorine compound. Hexafluorosilicic acid, sodium hexafluorosilicate, silicofluorination Potassium is not only a silicon compound but also a fluorine compound. Among these reaction retarders, silicon compounds and fluorine compounds are preferable, and amorphous silica, white carbon, hexafluorosilicic acid, sodium hexafluorosilicate, potassium silicofluoride, aluminum fluoride, and tetrafluorosilicic acid. More preferred. Silicon compounds and fluorine compounds have a higher dehydration temperature than other acids even under the same processing conditions, and show favorable results because these compounds have not only a reaction delay effect but also a vitrified layer on the surface of aluminum hydroxide. It has the effect of promoting formation or forming a coating layer on the surface of aluminum hydroxide, and it is presumed that the dehydration temperature rises because it is necessary to dehydrate these layers during heat dehydration. Two or more reaction retarders can be used in combination.

  0.05-10 mass parts is preferable with respect to 100 mass parts of aluminum hydroxide, 0.1-5 mass parts is more preferable, and the quantity of the reaction retarder mixed with aluminum hydroxide is 0.3-3 mass parts Is most preferred. When the amount is less than 0.05 parts by mass, boehmite formation of aluminum hydroxide cannot be sufficiently suppressed, and when the amount is more than 10 parts by mass, a reaction retarder may be mixed into the aluminum hydroxide as an impurity. Moreover, even if there is no actual damage as an impurity, if it exceeds 10 parts by mass, the amount of dehydration is relatively reduced. In addition, in the field of flame retardants, it is often practiced to mix aluminum hydroxide flame retardants with phosphorus, nitrogen, and other inorganic flame retardants to produce a synergistic effect, and when additives are added for this purpose May exceed this range.

  The heat-resistant aluminum hydroxide used in the present invention can increase the dehydration temperature by suppressing the boehmite conversion of aluminum hydroxide with a high heat history, and can maintain a sufficient dehydration amount. This greatly improves the contradictory relationship between the amount of dehydration and the amount of dehydration. More specifically, the 1% by mass dehydration temperature is about 210 to 230 ° C. for aluminum hydroxide that is not hydrothermally treated, whereas the heat resistant aluminum hydroxide of the present invention is 245 ° C. or higher, often 250 ° C. It is over ℃ and still maintains a sufficient amount of dehydration.

  The heat-resistant aluminum hydroxide (C) used in the present invention partially includes a mixture of boehmite and a mixture of aluminum hydroxide and boehmite, and preferably has a total dehydration amount of 30% by mass or more. More preferably, the boehmite conversion rate is 14% or less and the total dehydration amount is 32% by mass or more, and most preferably, the boehmite conversion rate is 0% and the total dehydration amount is 35% by mass.

  The heat-resistant aluminum of the present invention preferably has a 1% by mass dehydration temperature of 255 ° C. or more and a total dehydration amount of 30% by mass or more. In this case, the average particle size of the starting aluminum hydroxide is It is preferable that it is 2.5 μm or less.

  Here, it is preferable to contain the compounding quantity of (C) heat resistant aluminum hydroxide in the range of 1-50 mass parts with respect to 100 mass parts of resin components soluble in (A) dilute alkali solution.

  As the (D) phosphorus flame retardant used in the present invention, conventionally known organic phosphorus compounds can be used as flame retardant, and examples thereof include phosphazene compounds, melamine phosphate compounds, biphenyl phosphate compounds, and 9,10-dihydro. And organic phosphorus compounds such as a -9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative. Especially, it is preferable that they are a phosphazene compound and a DOPO derivative, and it is more preferable to use both together.

（但し、式中、Ｒ¹ 及びＲ² 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。）を挙げることができ、このとき、Ｒ¹ 及びＲ² の１価の有機基としてはフェニル基、アルキル基、アミノ基、アリル基等の基が好ましいものとして挙げられる。また、一般式（１）の末端基としては、水素原子、水酸基、アルキル基、アルコキシル基、アリールオキシ基、シアネート基等が挙げられる。 Here, as the phosphazene compound, a known phosphazene compound as a flame retardant can be used. For example, the phosphazene oligomer represented by the following general formulas (1) and (2)

(Wherein, R ¹ and R ² 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 of ¹ and R ² include a phenyl group, an alkyl group, an amino group, and an allyl group. Moreover, as a terminal group of General formula (1), 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 propoxyphosphazene oligomers, phenoxyphosphazene oligomers, cyanate phenylphosphazene oligomers, cyanophenoxyphosphazene oligomers, and methylphenoxyphosphazene oligomers.

  As these phosphazene compounds, phosphazene compounds having a thermal decomposition temperature of 250 ° C. or higher or a melting point of 80 ° C. or higher are preferably used from the viewpoints of contained heat resistance, moisture resistance, flame retardancy, chemical resistance, and the like. be able to. These phosphazene compounds can be used alone or in admixture of two or more.

  The DOPO derivative preferably has a (meth) acryloyl group which is a radical polymerizable group, and phosphorus atoms are taken into the matrix of the cured product during photopolymerization. Therefore, flame retardancy can be imparted without impairing flexibility and heat resistance.

（但し、式中、Ｒ³ はＨまたはＣＨ_３である。）を挙げることができる。 As this DOPO derivative, for example, a compound represented by the following general formula (3)

(Wherein R ³ is H or CH ₃ ).

  This DOPO derivative can be obtained, for example, by the following production method described in JP-A-7-48394.

と（メタ）アクリル酸でエステル化する事によって得られる。更に詳しく説明するならば、（メタ）アクリル酸の使用量は一般式（４）で表される化合物に対して、化学量論比以上に使用されるのが通常であり、一般にアルコールに対するカルボン酸のモル比は１．０〜２．０であるが好ましくは１．１〜１．５である。反応はエステル化触媒を使用し、生成する水は留去する事により促進される。このようなエステル化触媒は、硫酸、Ｐ−トルエンスルホン酸等の酸性触媒であり、その使用量はアクリル酸またはメタクリル酸に対して０．１〜１０モル％、好ましくは１〜５モル％使用される。 First, a compound represented by the following general formula (4)

And obtained by esterification with (meth) acrylic acid. More specifically, the amount of (meth) acrylic acid used is usually higher than the stoichiometric ratio with respect to the compound represented by the general formula (4). The molar ratio is 1.0 to 2.0, preferably 1.1 to 1.5. The reaction is promoted by using an esterification catalyst and distilling off the water produced. Such an esterification catalyst is an acidic catalyst such as sulfuric acid or P-toluenesulfonic acid, and the amount used is 0.1 to 10 mol%, preferably 1 to 5 mol% based on acrylic acid or methacrylic acid. Is done.

  It is advantageous to use an azeotropic solvent to distill off the water produced by the reaction. Such an azeotropic solvent has a boiling point of 60 to 130 ° C. and can be used if it can be easily separated from water. Suitable are aliphatic hydrocarbons such as n-hexane and n-heptane, aromatic hydrocarbons such as benzene and toluene, and alicyclic hydrocarbons such as cyclohexane. The amount used is usually from 5 to 70% by weight of the reaction mixture. The reaction temperature may be in the range of 60 to 130 ° C., but it is advantageous to carry out the reaction at 75 to 120 ° C. from the viewpoint of shortening the reaction time and preventing polymerization.

  Usually, a polymerization inhibitor is already added to (meth) acrylic acid, but a polymerization inhibitor may be added again during the reaction. Such polymerization inhibitors include hydroquinone, p-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 3-hydroxythiophenol, α-nitroso-β-naphthol, p-benzoquinone, 2,5- Examples include dihydroxy-p-quinone, phenothiazine, N-nitrosodiphenylamine, copper salt and the like. The amount used is usually 0.01 to 1% by mass relative to the reaction mixture. The (meth) acrylic acid ester of the present invention is used for industrial applications by washing with water or an aqueous alkaline solution as necessary, or by separating it from a solvent by a method such as vacuum distillation.

  These (D) phosphorus flame retardants can be used alone or in admixture of two or more. Moreover, it is preferable that the compounding quantity of this (D) phosphorus flame retardant is 1-50 mass parts with respect to 100 mass parts of (A) resin components soluble in a dilute alkali solution. Here, when a phosphazene compound is used, it is preferably 1 to 50 parts by mass, more preferably 1 to 30 parts by mass, and when a DOPO derivative is used, it is 5 to 50 parts by mass. Is preferred. Furthermore, when using together a phosphazene compound and a DOPO derivative, it is preferable to set it as 5-40 mass parts in total with respect to 100 mass parts of (A) resin components soluble in a dilute alkali solution.

  The (E) photopolymerization initiator used in the present invention is a known and commonly used photopolymerization initiator such as an active radical generator or a sensitizer that generates active radicals upon irradiation with actinic rays such as ultraviolet rays.

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

  Furthermore, this (E) photopolymerization initiator is composed of three compounds such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine. Photosensitizers such as secondary amines can be used alone or in combination of two or more.

  When this (E) photopolymerization initiator is used in combination, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by Ciba-Geigy Corporation, product) Name: Irgacure-907) and 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name: Kayacure DETX), 2-isopropylthioxanthone or 4-benzoyl-4'-methyldiphenyl sulfide Can be mentioned.

  Here, the blending amount of the (E) photopolymerization initiator is preferably in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the resin component (A) soluble in the diluted alkaline solution.

  As the diluent (F) used in the present invention, an organic solvent and / or a photopolymerizable monomer can be used. Examples of the organic solvent include ketones such as ethyl methyl ketone and cyclohexanone, toluene, xylene, Aromatic hydrocarbons such as tetramethylbenzene, methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether, etc. Glycol ethers, esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, alcohols such as ethanol, propanol, ethylene glycol, propylene glycol S, octane, aliphatic hydrocarbons, petroleum ether decane, may be mentioned petroleum naphtha, hydrogenated petroleum naphtha, petroleum solvents such as solvent naphtha or the like.

  On the other hand, as the photopolymerizable monomer, hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, glycols such as ethylene glycol, methoxytetraethylene glycol and polyethylene glycol Mono- or di (meth) acrylates, (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, and aminoalkyls such as N, N-dimethylaminoethyl (meth) acrylate ( (Meth) acrylates, hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, polyhydric alcohols such as tris-hydroxyethyl isocyanurate, these Multivalent (meth) acrylates of ethylene oxide or propylene oxide adducts of phenols such as polyvalent (meth) acrylates of styrene oxide or propylene oxide adducts, phenoxyethyl (meth) acrylate, polyethoxydi (meth) acrylate of bisphenol A , Glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, glycidyl ether (meth) acrylates such as triglycidyl isocyanurate, ε-caprolactone modified (meth) acrylates such as caprolactone-modified tris (acryloxyethyl) isocyanurate And melamine (meth) acrylate. This (F) diluent can be used alone or as a mixture of two or more.

  The blending amount of the (F) diluent is preferably 1 to 100 parts by weight, particularly 10 to 80 parts by weight, based on 100 parts by weight of the resin component (A) soluble in the diluted alkaline solution. preferable.

  The purpose of use of this diluent is, in the case of a photopolymerizable monomer, (A) diluting a resin component soluble in a dilute alkaline solution, adjusting the viscosity to a state where it can be easily applied, and enhancing photopolymerizability. In the case of an organic solvent, (A) by dissolving and diluting a resin component that is soluble in a dilute alkaline solution, adjusting the viscosity to a state where it is easy to apply, and applying it in a liquid state and then drying it It forms a film. Therefore, 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 resin composition of the present invention may further include barium sulfate, barium titanate, silicon oxide powder, for the purpose of improving properties such as adhesion and hardness, Known and commonly used inorganic fillers such as finely divided silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, and mica powder can be used.

  The amount of the inorganic filler used is preferably 0 to 60% by mass and particularly preferably 5 to 40% by mass with respect to the entire photosensitive resin composition of the present invention.

  Furthermore, if necessary, known and commonly used colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, hydroquinone, hydroquinone monomethyl ether, t-butyl Known and conventional polymerization inhibitors such as catechol, pyrogallol and phenothiazine, known and conventional thickeners such as asbestos, olben, benton and montmorillonite, antifoaming agents such as silicones, fluorines and polymers, leveling agents and imidazoles In addition, known and commonly used additives such as silane coupling agents such as thiazole type and triazole type can be used.

  Also known binder resins such as copolymers of ethylenically unsaturated compounds such as acrylate esters and polyester resins synthesized from polyhydric alcohols and polybasic acid compounds, polyester (meth) acrylates, polyurethanes ( It can be used as long as it does not affect various properties as a solder resist such as photopolymerizable oligomers such as (meth) acrylate and epoxy (meth) acrylate.

  In addition to the essential components (A) to (F) described above, the photosensitive resin composition of the present invention is added and blended with other components as necessary, and then mixed uniformly with a three-roll mill or the like. Can be manufactured.

  The flexible printed wiring board of the present invention is a flexible printed wiring board in which the photosensitive resin composition of the present invention in the form of a varnish is bonded to one side or both sides of a polyimide film with a hot roll to form a wiring pattern. A flexible copper-clad laminate is manufactured by the usual method of applying to the top and then heat-curing, and if necessary, drilling through-hole plating is performed, or a cover lay with holes in predetermined locations is stacked and heated. It can also be produced by an ordinary method of pressure forming.

  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 produced by the usual method of forming the circuit.

  Next, the present invention will be described using examples and comparative examples. In addition, it showed in Table 1 about the compounding quantity of each component used by each of the Example and the comparative example.

、熱硬化成分としてビフェニル型エポキシ樹脂（ジャパンエポキシレジン株式会社製、商品名：エピコート ＹＬ６１２Ｈ） １３．０質量部、硬化剤としてイミダゾール系重合触媒（四国化成工業株式会社製、商品名：２Ｅ４ＭＺ） １．３質量部及びメラミン １．３質量部、耐熱性水酸化アルミニウム（河合石灰工業株式会社製、商品名：ＡＬＨ；１質量％脱水温度 ２６０℃、全脱水量３５質量％） ６．５質量部、フタロシアニンブルー １．３質量部、微粉シリカ（日本アエロジル株式会社製、商品名：アエロジルＲ９７２） ３．３質量部並びにホスファゼン化合物としてフェノキシホスファゼンオリゴマー（融点：１１０℃） ３．３質量部を配合し、３本ロールミルで混練することで感光性熱硬化型樹脂組成物を製造した。 Example 1
Kayrad ZFR1122 (trade name, manufactured by Nippon Kayaku Co., Ltd.) as an epoxy acrylate compound, 54.0 parts by mass, Kayarad DPHA (trade name, manufactured by Nippon Kayaku Co., Ltd.), which is a photopolymerizable monomer, as a diluent, 6.5 parts by mass Darocur TPO (trade name: photopolymerization initiator 1 manufactured by Ciba-Geigy Co., Ltd.) as a photopolymerization initiator 4.5 parts by mass and Irgacure 184 (trade name: photopolymerization initiator 2 manufactured by Ciba-Geigy Co., Ltd.) 0 part by mass, DOPO derivative represented by the following chemical formula (5) 6.6 parts by mass

13.0 parts by mass of a biphenyl type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat YL612H) as a thermosetting component, and an imidazole polymerization catalyst (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: 2E4MZ) as a curing agent 1.3 parts by mass and 1.3 parts by mass of melamine, heat-resistant aluminum hydroxide (manufactured by Kawai Lime Industry Co., Ltd., trade name: ALH; 1% by mass dehydration temperature 260 ° C., total dehydration amount 35% by mass) 6.5 parts by mass 1.3 parts by weight of phthalocyanine blue, fine silica (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil R972) 3.3 parts by weight and 3.3 parts by weight of a phenoxyphosphazene oligomer (melting point: 110 ° C.) as a phosphazene compound A photosensitive thermosetting resin composition was produced by kneading with a three-roll mill.

(Comparative Example 1)
Aluminum hydroxide (made by Showa Denko KK, trade name: H421, 1 mass% dehydration temperature 200 ° C.) instead of heat-resistant aluminum hydroxide is photosensitive by the same composition and operation as in Example 1 except that 6.5 parts by mass was used. A thermosetting resin composition was produced.

(Comparative Example 2)
Photosensitive thermosetting resin by the same composition and operation as in Example 1 except that 6.5 parts by mass of spherical silica (trade name: FB-3SDX) manufactured by Denki Kagaku Kogyo Co., Ltd. was used instead of heat-resistant aluminum hydroxide. A composition was prepared.

(Comparative Example 3)
Brominated epoxy resin (Dainippon Ink Co., Ltd., trade name: Epicron 1121) 19.3 parts by mass in place of the biphenyl type epoxy resin, and the same composition as Comparative Example 2 except that the DOPO derivative and phosphazene compound were eliminated The photosensitive thermosetting resin composition was manufactured by the operation.

(Comparative Example 4)
Instead of heat-resistant aluminum hydroxide, 6.5 parts by mass of spherical silica (trade name: FB-3SDX, manufactured by Denki Kagaku Kogyo Co., Ltd.) was used, phosphazene oligomer was not used, and the DOPO derivative was 10.0 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 5)
Instead of the heat-resistant aluminum hydroxide, 6.5 parts by mass of spherical silica (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: FB-3SDX) was used, the DOPO derivative was not used, and the phosphazene oligomer was 10.0 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 6)
A photosensitive thermosetting resin composition was produced by the same composition and operation as in Example 1 except that the DOPO derivative and the phosphazene compound were not used and the heat-resistant aluminum hydroxide was changed to 16.4 parts by mass.

  The 1% by mass dehydration temperature of aluminum hydroxide used in Example 1 and Comparative Example 1 is in accordance with JIS K 0129. From room temperature to 100 ° C, the temperature is increased by 20 ° C per minute, and from 100 ° C to 500 ° C. The thermogravimetric analysis was conducted under the temperature rising condition of 5 ° C. per minute.

(Test example)
The copper-clad polyimide film substrate (copper) by which the resin composition obtained by the Example and the comparative example was pattern-formed so that it might become a thickness of 20-30 micrometers using a 150 mesh polyester screen with a screen printer, respectively. The entire surface was applied to a thickness of 18 μm / polyimide film thickness of 25 μm, and the coating film was dried for 30 minutes with a hot air dryer at 80 ° C. 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 ). Then, 1 kgf / cm ² using 1% strength by weight sodium carbonate aqueous solution is developed by spraying for 1 minute, the unexposed portion is dissolved and removed, and further cured by heat curing at 150 ° C. for 60 minutes. A membrane was obtained.

  About this cured film, flame retardancy, insulation resistance, gas generation amount during combustion, adhesion, pencil hardness, resolution, solder heat resistance, chemical resistance, folding resistance are based on the following methods and standards The results are shown in Table 1.

[Flame retardance test]
The test was conducted according to the UL94 flame retardant test.
[Insulation resistance]
The test was conducted according to IEC-PB112.
[Gas analysis during combustion]
The sample was burned in air at 750 ° C. for 10 minutes, the gas generated at that time was absorbed in water as an absorbing solution and analyzed by ion chromatography, and the hydrogen bromide concentration in 100 g of the generated gas was calculated.

[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.
[Pencil hardness]
It measured according to JISK5400.
[Resolution]
Using an electron microscope, the opening state when alkali development on the substrate was confirmed.

[Solder heat resistance]
The test piece was floated on a solder bath at 260 ° C. for 1 minute, observed for the presence or absence of swelling, and evaluated according to the following criteria. This test was performed twice for the same specimen, and the results are shown in the table.
◎… No swelling, ○… Partial swelling, ×… All swelling [chemical resistance]
About each of 10 mass% sulfuric acid, 10 mass% 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 resist was generated with an MIT folding resistance tester at R = 0.8 mm and a load of 4.9 N was measured.

  From this result, the photosensitive thermosetting resin composition of the present invention is in no way inferior to the composition using a conventional brominated epoxy resin and a halogen-based flame retardant in any characteristics, and at the time of combustion. It has been found that it has an excellent characteristic that hydrogen bromide, which has been regarded as a problem, does not occur.

Claims (4)

(A) a resin component having a (meth) acryloyl group and a carboxyl group in one molecule and soluble in a dilute alkali solution;
(B) a thermosetting component having an epoxy group;
(C) a heat-resistant aluminum hydroxide having a 1% by mass dehydration temperature of 255 ° C. or more and a total dehydration amount of 30% by mass or more;
(D) a phosphorus-based flame retardant,
(E) a photopolymerization initiator;
(F) a diluent;
Barbed including,
The (D) phosphorus flame retardant is a combination of a phosphazene compound and a DOPO derivative, and
(A) 1-50 parts by mass of (C) heat-resistant aluminum hydroxide and (D) phosphorus flame retardant 5-40 parts by mass with respect to 100 parts by mass of the resin component soluble in the dilute alkali solution. An alkali development type photosensitive resin composition characterized by comprising.   The heat-resistant aluminum hydroxide (C) is produced by hydrothermal treatment using a mixture of aluminum oxide and a reaction retarder that delays boehmite formation, or by pressurization and heating in a steam atmosphere. The photosensitive resin composition according to claim 1, wherein (A) 1-100 parts by mass of the thermosetting component having an epoxy group (B) 1-100 parts by mass of the photopolymerization initiator (E) with respect to 100 parts by mass of the resin component soluble in the dilute alkali solution. The photosensitive thermosetting resin composition according to claim 1 , comprising 1 to 100 parts by mass of the diluent (F). A flexible printed wiring board composed of a polyimide layer and a copper layer, or a polyimide layer, an adhesive layer and a copper layer,
A flexible printed wiring board comprising a resin layer formed of the photosensitive resin composition according to claim 1 on the surface of the flexible printed wiring board.