WO2006085494A1

WO2006085494A1 - Flame-retardant composition for solder resist and use thereof

Info

Publication number: WO2006085494A1
Application number: PCT/JP2006/301915
Authority: WO
Inventors: Yoshio Miyajima; Kazuhiko Ooga; Satoru Ishigaki
Original assignee: Showa Denko KK
Current assignee: Resonac Holdings Corp
Priority date: 2005-02-08
Filing date: 2006-01-30
Publication date: 2006-08-17
Anticipated expiration: 2007-08-08

Abstract

A flame-retarding composition for a solder resist as claimed in the present invention comprises an unsaturated group-containing polycarboxylic acid resin (A), wherein a polybasic acid anhydride (c) is added to the reaction product of a bisphenol epoxy resin (a) represented with the following general formula (I): (wherein, n represents an integer of 1 to 10, X is selected from a methylene group, ethylidene group, isopropylidene group, sulfonyl group and single bond, and Y represents a hydrogen atom or a 2,3-epoxypropyl group) with an unsaturated group-containing monocarboxylic acid (b), a photoinitiator (B), an epoxy resin (C), a flame retardant (D) and a metal hydrate compound (E), and has superior low tack, flexibility and PCT resistance.

Description

DESCRIPTION

FLAME-RETARDANT COMPOSITION FOR SOLDER RESIST

AND USE THEREOF

Cross-References to Related Applications This application claims benefit under 35 U . S . C . Section 119 (e) to the United States Provisional Application Serial No . 60/653995 filed February 18 , 2005.

Technical Field

The present invention relates to a flame-retarding ( flame-retardant) composition for a solder resist for forming a protective film that is used in the production of printed circuit boaxds and so forth. More particularly, the present invention relates to a solder resist having superior tack resistance, flexibility and PCT resistance, and its use .

Background Art

Various board protecting means are required in the production of printed circuit boards such as the resist used during etching and the solder resist used in the soldering step . A solder resist used in the production process of film-type printed circuit boards (flexible printed circuit ( FPC) boards ) used in small devices is also required to protect unrelated wiring in the soldering step for installing components .

Cover layer films, consisting of laminating polyimide films punched out to a predetermined form, or cover coatings, which consisted of printing an ink composed of a heat-resistant material, were used in the prior art for the purpose of protecting these boards . These cover layer films and cover coatings also served as protective films for the wiring after soldering, and were required to have heat resistance and insulating properties during soldering as well as flexibility that prevented bending and crack formation during incorporation of the board. Moreover, FPC used in high- voltage devices were also required to have flame retardation . Although cover layer films formed by punching out a polyimide film satisfy the aforementioned required characteristics and are currently used most commonly, in addition to requiring an expensive metal mold for punching, even greater costs are incurred since the punched out film has to be positioned and laminated manually. In addition, there is also the problem of it being difficult to form a fine pattern .

A method for solving these problems has been proposed in which a photosensitive composition is coated onto a board as a liquid or laminated as a film., -

According to this method, after forming a coating on the board, the film is exposed and developed using photographic technology followed by heating to easily allow the formation of a cover coating or cover layer film having a minute pattern, and various photosensitive compositions have been developed thus far.

However, none of these photosensitive compositions of the prior art satisfy all of the characteristics ^'required for use with FPC . For example, a photosensitive composition has been proposed that is composed of a prepolymer, in which a polybasic acid anhydride is added and allowed to react with a Novolak epoxy vinyl ester resin, a photopolymerization initiator, a diluent and an epoxy resin (see Japanese Examined Patent Publication No . 1-54390 (Patent Document 1) ) . Although this composition has satisfactory heat resistance and insulating properties, it is not flexible and unsuitable for FPC .

In addition, a resin composition has been proposed that contains an ethylenic unsaturated group-containing polycarboxylic acid resin, diluent and polysulfide- modified epoxy resin (see Japanese Unexamined Patent Publication No . 2002-308966 ( Patent Document 2 ) ) . Although this composition has satisfactory flexibility, it demonstrates strong tack and lacks heat resistance, thereby having the problem of being limited in the applications in which it can be used. A photosensitive resin composition has been proposed as a way to impart both flame retardation and flexibility that comprises a binder polymer having for its copolymer component tribromophenyl (meth) acrylate, a bisphenol A (meth) acrylate compound, a photopolymerization initiator, an amino resin and an aromatic phosphoric acid ester compound (see Japanese Unexamined Patent Publication No . 2001-042526 ( Patent Document 3) ) . Although this composition has satisfactory flame retardation and flexibility, it has the problem of low PCT resistance and low HHBT resistance .

In this manner, it is not easy to obtain a flame- retarding composition for a solder resist that is provided with both flexibility and high flame retardation that satisfies the criteria of UL standards , while also having superior low tack, solder resistance, PCT resistance and HHBT resistance, thereby resulting in the need for further improvement .

[Patent Document 1] Japanese Examined Patent ^■ Publication No . 1-54390

[Patent Document 2] Japanese Unexamined Patent Publication

No . 2002-308966

[Patent Document 3] Japanese Unexamined Patent Publication

No . 2001-042526 Summary of the Invention

An obj ect of the present invention is to provide a flame-retarding composition for a solder resist provided with low tack, flame retardation, PCT resistance, soldering heat resistance and flexibility, and more particularly, a flame-retarding composition for a solder resist that can be preferably used as a solder resist for FPC in particular . In addition, an obj ect of the present invention is to provide a suitable method for forming a heat-resistant, protective film by using the aforementioned flame-retarding composition for a solder resist .

As a result of conducting extensive studies , the inventors of the present invention found that the aforementioned problems can be solved by using a specific composition of an unsaturated group-containing polycarboxylic acid resin and flame retardant , and completed the present invention on the basis of this finding . Namely, the present invention relates to a flame-retarding composition for a solder resist, its cured product , its curing method and its use as defined in [ 1] to [20] below .

[1] A flame-retarding composition for a solder resist comprising : an unsaturated group-containing polycarboxylic acid resin (A) , wherein a polybasic acid anhydride (c) is added to the reaction product of a bisphenol epoxy resin (a) represented with the following general formula ( I) :

(wherein, n represents an integer of 0 to 10 , X is selected from a methylene group, ethylidene group, isopropylidene group, sulfonyl group and single bond, and Y represents a hydrogen atom or a 2 , 3-epoxypropyl group) with an unsaturated group-containing monocarboxylic acid (b) , a photoinitiator (B) , an epoxy resin (C) , a flame retardant ( D) and a metal hydrate compound (E) .

[2] A flame-retarding composition for a solder resist as set forth in [1] above, wherein 10 to 84% of Y in the bisphenol epoxy resin (a) represented by general formula ( I ) is a 2 , 3-epoxypropyl group .

[3] A flame-retarding composition for a solder resist as set forth in [ 1] above, wherein the polybasic acid anhydride (c) is an anhydride of a polybasic acid selected from phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl ^■ hexahydrophthalic anhydride, and methyl endomethylene tetrahydrophthalic anhydride . [ 4 ] A flame-retarding composition for a solder resist as set forth in [1] above, wherein the acid value of the • solid component of the unsaturated group-containing polycarboxylic acid resin (A) is 50 to 140 mgKOH/g . [ 5] A flame-retarding composition for a solder resist as set forth in [ 1] above, wherein the flame retardant (D) is a brominated epoxy resin (d) and/or phosphorous compound (e) .

[ 6] A flame-retarding composition for a solder resist as set forth in [5] above, wherein the brominated epoxy resin (d) is a brominated bisphenol A epoxy resin .

[7 ] A flame-retarding composition for a solder resist as set forth in [ 6] above, wherein the content of the^' brominated epoxy resin (d) in the solid component of the ^■flame-retarding composition for a solid resist is within the range of 4 to 13% by weight in terms of the bromine content .

[ 8 ] A flame-retarding composition for a solder resist as set forth in [ 5] above, wherein the phosphorous compound (e) is a phosphoric acid ester . [ 9] A flame-retarding composition for a solder resist as set forth in [ 5] above, wherein the content of the phosphorous compound (e) in the solid component of the flame-retarding composition for a solder resist is within the range of 2 to 10% by weight . [ 10 ] A flame-retarding composition for a solder resist as set forth in [ 1] above, wherein the amount of heat absorbed during thermal decomposition of the metal hydrate compound (E) is 400 to 2 , 500 J/g. [11] A flame-retarding composition for a solder resist as set forth in any of [1] above, wherein the metal hydrate compound (E) is aluminum hydroxide and/or magnesium hydroxide .

[12] A flame-retarding composition for a solder resist as set forth in [1] above, wherein the content of the metal hydrate compound (E) in the solid component of the flame- retarding composition for a solder resist is within the range of 5 to 30% by weight .

[13] A flame-retarding composition for a solder resist as set forth in [5] above, wherein the equivalent of epoxy groups contained in the epoxy resin (C) and the brominated epoxy resin (d) is within the range of 0.5 to 3.0 ( functional group equivalent ratio) relative to the equivalent of carboxyl groups in the flame-retarding composition for a solder resist .

[14 ] A flame-retarding composition for a solder resist as set forth in [1] above further comprising a photocurable monomer and/or oligomer ( F) .

[15] A flame-retarding composition for a solder resist as set forth in [1] above further comprising an epoxy heat curing catalyst (G) . ' [16] A flame-retarding composition for a solder resist as set forth in [1] above, wherein the viscosity is 500 to 500 , 000 mPa - s (25°C) .

[17 ] A cured product of a flame-retarding composition for a solder resist as set forth in [ 1] above . [18 ] A flame-retarding composition for a solder resist as set forth in [ 1] above, wherein the flame retardation in accordance with UL94VTM standards of a laminate having a cured layer of the flame-retarding composition for a solder resist of 10 to 45 μm each on both sides of a polyimide board having a thickness of 10 to 80 μm satisfies the criteria of VTM-O .

[19] A method for curing a flame-retarding composition for a solder resist comprising a step in which, after coating a flame-retarding composition for a solder resist as set forth in [1] above onto a board, it is dried for 2 to 90 minutes at a temperature range of 50 to 120°C to a 5 thickness of 5 to 80 μm followed by exposure, development and heat curing .

[20 ] An insulating protective coating produced from a flame-retarding composition for a solder resist as set forth in [1] above . 0 [21] A printed circuit board partially or entirely coated with the cured product as set forth in [17 ] above . [^•22] A flexible printed circuit board partially or entirely coated with the cured product as set forth in [ 17 ] above . 5 [23] An electronic component containing the cured product as set forth in [17 ] above . Detailed Description of the Invention

1. Unsaturated Group-Containing Polycarboxylic Acid Resin (A) 0 An unsaturated group-containing polycarboxylic acid resin (A) used in the flame-retarding composition for a solder resist of the present invention can be obtained by adding a polybasic acid anhydride (c) to the reaction product of a bisphenol epoxy resin (a) represented by the 5 following general formula ( I ) :

(wherein, n represents an integer of 0 to 10 , X is selected from a methylene group, ethylidene group, isopropylidene group, sulfonyl group and single bond, and 5 Y represents a hydrogen atom or a 2 , 3-epoxypropyl group) with an unsaturated group-containing monocarboxylic acid

(b) . Due to the alkaline developing properties of solder resist, the acid value of the solid component of the unsaturated group-containing polycarboxylic acid resin (A) used in the present invention can preferably be within the range of 50 to 140 mgKOH/g. If the acid value of the solid component is less than 50 mgKOH/g, the alkaline developing properties of the solder resist become poor, while if the acid value of the solid component exceeds 140 mgKOH/g, flexibility, HHBT resistance and PCT resistance of the cured product of the flame-retarding composition for a solder resist become poor . 1-1. Bisphenol Epoxy Resin (a)

The .bisphenol epoxy resin (a) used in the flame- retarding composition for a solder resist of the present invention is represented by the following general formula (I) :

• (wherein, n represents an integer of 0 to 10, X is selected from a methylene group, ethylidene group, isopropylidene group, sulfonyl group and single bond, and Y represents a hydrogen atom or a 2 , 3-epoxypropyl group) . X is preferably a methylene group, ethylidene group or isopropylidene group, and particularly preferably an isopropylidene group, from the viewpoint of the hydrolysis resistance of the cured product of the flame- retarding composition of a solder resist . 10 to 84% of Y is preferably a 2, 3-epoxypropyl group, and more preferably 50 to 75% . In the case less than 10% of Y is a 2, 3-epoxypropyl group, the soldering heat resistance of the cured product of the flame-retarding composition for a solder resist becomes poor . On the other hand, in the case the mean value of Y exceeds 84% for the percentage of the 2, 3-epoxypropyl group, tack increases following coating and drying of the flame-retarding composition for a solder resist on a board, thereby causing it to stick to a photomask during exposure and resulting in poor workability.

A bisphenol epoxy resin like that shown in general formula ( I ) in which Y is a 2 , 3-epoxypropyl group can be obtained from a reaction between a bisphenol A epoxy resin, bisphenol F epoxy resin or bisphenol S epoxy resin and epihalohydrin .

1-2. Production Method of Bisphenol Epoxy Resin (a) Represented by General Formula ( I ) A bisphenol epoxy resin (a) used to obtain an unsaturated group-containing polycarboxylic acid resin (A) used in the present invention and represented by general formula (I) is the reaction product of additionally glycidylating the alcoholic hydroxyl groups of a bisphenol epoxy resin in which Y consists entirely of hydrogen atoms with an epihalohydrin such as epichlorhydrin . An example of a method for obtaining this reaction product involves reacting the alcoholic hydroxyl groups of the bisphenol epoxy resin with an ^■ epihalohydrin such as epichlorhydrin preferably in the presence of dimethylsulfoxide . The amount of epihalohydrin used may be 1 or more equivalents with respect to 1 equivalent of alcoholic hydroxyl groups . In the case of using dimethylsulfoxide, the amount used is preferably 5 to 300% by weight with respect to the bisphenol epoxy resin . If this amount is less than 5% by weight, the reaction between the alcoholic hydroxyl groups in the bisphenol epoxy resin and the epihalohydrin slows and requires a long reaction time . On the other hand, if this amount exceeds 300% by weight, there are no longer any effects from increasing the amount used and volumetric efficiency also decreases , thereby making this undesirable . An alkaline metal hydroxide is used when carrying out this reaction . Although examples of alkaline metal hydroxides that can be used include sodium hydroxide and potassium hydroxide, sodium hydroxide is preferable . The amount of alkaline metal hydroxide used may be 1 equivalent with respect to the epoxified alcoholic hydroxyl groups . The alkaline metal hydroxide used here may be in the state of a solid or aqueous solution . The reaction temperature is preferably 30 to 100°C . If the reaction temperature is lower than 30°C, the reaction slows and requires a long time . On the other hand, if the reaction temperature exceeds 100°C, numerous side reactions occur, thereby making this undesirable . Following completion of the reaction, excess epihalohydrin and dimethylsulfoxide are distilled off under reduced pressure followed by dissolving the formed resin in an organic solvent, after which a dehydrohalogenation reaction can be carried out with alkaline metal hydroxide . On the other hand, following completion of the reaction, after separating the by- product salts and dimethylsulfoxide by rinsing separation and distilling off the excess epihalohydrin from the oily layer under reduced pressure, the resin may be dissolved in an organic solvent followed by a dehydrohalogenation ^' reaction with alkaline metal hydroxide . Examples of organic solvents that can be used include methyl isobutyl ketone, benzene, toluene and xylene . These organic solvents can be used alone or as a mixture . 1-3. Unsaturated Group-Containing Monocarboxylic Acid (b) Examples of unsaturated group-containing monocarboxylic acid (b) include acrylic acid, acrylic acid dimers, methacrylic acid, β-stearyl acrylic acid, β- furfuryl acrylic acid, erotic acid, α-cyanocinnamic acid, cinnamic acid, and hemi-esters that are the reaction products of saturated or unsaturated dibasic acid anhydrides and (meth) acrylate derivatives having one hydroxyl group in their molecule, or hemi-esters that are - li ¬

the reaction products of saturated or unsaturated group- containing monoglycidyl compounds . Examples of hemi- esters include hemi-esters obtained by reacting at an equimolar ratio a saturated or unsaturated dibasic acid anhydride such as succinic anhydride, maleic anhydride, hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, itaconic anhydride and methyl endomethylene tetrahydrophthalic anhydride, with a (meth) acrylate derivative having one hydroxyl group in its molecule such as hydroxyethyl (meth) acrylate, hydroxypropyl

(meth) acrylate, hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, glycerin di (meth) acrylate, trimethylol propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and (meth) acrylates of phenyl glycidyl ethers , as well as hemi-esters obtained by reacting at an equimolar ratio a saturated or unsaturated dibasic acid (such as succinic acid, maleic acid, adipic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, itaconic acid or fumaric acid) with an unsaturated group- containing monoglycidyl compound (such as glycidyl (meth) acrylate) . These unsaturated group-containing monocarboxylic acids can be used alone or as a mixture . ^■A particular preferable example of this unsaturated group-containing monocarboxylic acid is acrylic acid. 1-4. Polybasic Acid Anhydride (c)

Examples of polybasic acid anhydride (c) include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, endomethylene tetrahydrophthalic anhydride, methyl endomethylene tetrahydrophthalic anhydride, itaconic anhydride, succinic anhydride, itaconic anhydride dodecenyl succinic anhydride, chlorendic anhydride, trimellitic anhydride, pyromellitic anhydride and benzophenone tetracarboxylic anhydride . These can be used alone or as a mixture . Phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, endomethylene tetrahydrophthalic anhydride and methyl endomethylene tetrahydrophthalic anhydride are used preferably, and tetrahydrophthalic anhydride is used particularly preferably, in consideration of the PCT resistance and HHBT resistance of the cured solder resist .

1-5. Production Method of Unsaturated Group-Containing Polycarboxylic Acid Resin (A) The unsaturated group-containing polycarboxylic acid resin (A) used in the present invention can be obtained by adding a polybasic acid anhydride (c) to the reaction product of a bisphenol epoxy resin (a) represented by general formula ( I ) with an unsaturated group-containing monocarboxylic acid (b) .

Unsaturated group-containing monocarboxylic acid (b) is preferably reacted with bisphenol epoxy resin (a) at a ratio of 0.8 to 1.3 moles, and particularly preferably at a ratio of 0.9 to 1.1 moles, to 1 equivalent of the epoxy groups of bisphenol epoxy resin (a) . During the reaction, it is preferable to use as diluent an organic solvent, examples of which include ketones such as^' ethyl methyl ketone or cyclohexanone, aromatic hydrocarbons ^•such as toluene, xylene or tetramethyl benzene, glycol ethers such as dipropylene glycol dimethyl ether or dipropylene glycol diethyl ether, esters such as ethyl acetate, butyl acetate, butyl cellosorb acetate or carbitol acetate, aliphatic hydrocarbons such as octane or decane, and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha or solvent naphtha; or a reactive monomer such as carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylol propane tri (meth) acrylate, tris (hydroxyethyl) isocyanurate tri (meth) acrylate or dipentaerythritol hexa (meth) acrylate . It is also preferable to use a catalyst to further accelerate the reaction, examples of which include triethylamine, benzyl dimethyl amine, methyl triethyl ammonium chloride, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium iodide, triphenyl phosphine, triphenyl stibine, chromium octanoate and zirconium octanoate . The amount of catalyst used is preferably 0.1 to 10% by weight with respect to the mixture of reaction raw materials . It is also preferable to use a polymerization inhibitor to prevent polymerization during the reaction, examples of which include hydroquinone, methyl hydroquinone, hydroquinone monomethyl ether, catechol and pyrogallol, and the amount used is preferably 0.01 to 1% by weight with respect to the mixture of reaction raw materials . The reaction temperature is preferably 60 to 150°C . In addition, the reaction time is preferably 5 to 60 hours . The addition reaction product of bisphenol epoxy resin (a) shown in general formula (I) and unsaturated group- containing monocarboxylic acid (b) can be obtained in this manner . Next, the reaction between the addition reaction product and the aforementioned polybasic acid anhydride (c) is preferably carried out using 0.1 to 0.84 equivalents of polybasic acid anhydride (c) per 1 ^'equivalent of hydroxyl groups in the reaction product . The reaction temperature is preferably 60 to 150°C . The reaction time is preferably 1 to 10 hours . 2. Photoinitiator (B)

Examples of photoinitiators that can be used include benzophenones such as benzophenone, benzoyl benzoic acid, 4-phenyl benzophenone, hydroxybenzophenone and 4 , 4 ' - bis (diethylamine) benzophenone, benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether and benzoin isobutyl ether, acetophenones such as 4- phenoxydichloroacetophenone, 2-hydroxy-2-methyl-l- phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2- methylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2- hydroxy di-2-methyl-l-propan-l-one, 1-hydroxy-cyclohexyl- phenyl ketone, 2 , 2-dimethoxy-l, 2-diphenylethan-l-one, 2 , 2-diethoxy- 1, 2-diphenylethanone, 2-metyyl-l- [4- (methylthio) phenyl] -2- morpholinopropanone-1, 4-t-butyl- dichloroacetophenone, 4-t- butyl-trichloroacetophenone, diethoxyacetophenone, 2-benzyl- 2-dimethylamino-l- ( 4- morpholinophenyl) -butanone-1, and 1-phenyl-l , 2- propanedione-2- (o-ethoxycarbonyl) oxime, thioxanthenes such as thioxanthene, 2-chlorothioxanthene, 2-methyl thioxanthene and 2 , 4-dimethyl thioxanthene, alkyl anthraquinones such as ethyl anthraquinone and butyl anthraquinone, and acyl phosphine oxides such as 2 , 4 , 6- trimethylbenzoyl diphenyl phosphine oxide . These can be used alone or as a mixture of two or more types . In addition, these photoinitiators can be used in combination with a photosensitizer .

Preferable photoinitiators include benzophenones, acetophenones and acyl phosphine oxides . Specific examples include 4 , 4 ' -bis (diethylamino) benzophenone, 2- benzyl-2- dimethylamino-1- ( 4-morpholinophenyl) -butanone-1 and 2 , 4 , β-trimethylbenzoyl diphenyl phosphine oxide . The blended amount of these photoinitiators is preferably 0.3 to 15% by weight, and more preferably 1 to ^• 10% by weight, within the solid component of the flame- retarding composition for a solder resist . Curing may be inadequate if the blended amount of photoinitiator is less than 1% by weight . 3. Epoxy Resin (C)

There are no particular limitations on epoxy resin (C) , and examples include phenol Novolak type, cresol Npvolak type, biphenol type and bixylenol type epoxy resins, epoxy resins of polycondensates of phenol and hydroxybenzaldehyde, triglycidyl isocyanurate and triphenyl methane type epoxy resins, N-glycidyl type epoxy resins , Novolak type epoxy resins of bisphenol A, rubber-modified epoxy resins, dicyclopentadiene phenolic epoxy resins, silicone-modified epoxy resins and ε- caprolactone-modified epoxy resins . One type of two or more types of these epoxy resins can. be used in combination . Among these epoxy resins, phenol Novolak type, cresol Novolak type, biphenol type and bixylenol type epoxy resins, epoxy resins of polycondensates of phenol and hydroxybenzaldehyde and triglycidyl isocyanurate are preferable since they increase- the soldering heat resistance of the cured flame-retarding composition for a solder resist . 4. Flame Retardant (D)

There are no particular limitations on flame retardant ( D) used in the present invention, and examples include bromine compounds , phosphorous compound (e) and antimony compounds . Specific examples of bromine compounds include brominated epoxy resin (d) , tetrabromo bisphenol A carbonate oligomer, tetrabromo bisphenol A, tetrabromo bisphenol A-bis (2 , 3- dibromopropylether) , tetrabromo bisphenol A-bis (allylether) , tetrabromo bisphenol A-bis (ethoxylate) , tetrabromo bisphenol S, tetrabromo bisphenol S-bis (2 , 3-dibromopropylether) , hexabromobenzene, hexabromocyclododecane, decabromodiphenyl oxide, octabromodiphenyl oxide, ethylene bis (pentabromophenyl) , ethylene bis (tetrabromophthalimide) , tetrabromo phthalic anhydride, tribromophenol, tris (tribromophenoxy) triazine, polybromophenylene oxide, bis (tribromophenoxyethane) , tribromoneopentyl glycol, dibromoneopentyl glycol, pentabromobenzyl acrylate, dibromostyrene, tribromostyrene, poly (pentabenzylacrylate) and brominated polystyrene . Among these, brominated epoxy resin (d) and phosphorous compound (e) are preferable . 4-1. Brominated Epoxy Resin (d)

Specific examples of brominated epoxy resin (d) used in the flame-retarding composition for a solder resist of the present invention include brominated bisphenol A type epoxy resin, brominated cresol Novolak type epoxy resin and brominated phenyl glycidyl ether . Brominated bisphenol A type epoxy resin is particularly preferable . The content of brominated epoxy resin (d) in the solid component of the flame-retarding composition for a solder resist is preferably within the range of 4 to 13% by weight in terms of the bromine content . If the bromine content is less than 4% by weight, flame retardation in the case of using for a solder resist is inadequate, while if the bromine content exceeds 13% by weight, alkaline developing properties worsen . 4-2. Phosphorous Compound (e)

There are no particular limitations on phosphorous compound (e) used in the flame-retarding composition for a solder resist of the present invention, and it is preferably a phosphoric acid ester . The combined use of a phosphoric acid ester compound is preferable since it enables flexibility to be enhanced without impairing flame retardation . Specific examples of phosphoric acid ester compounds include tributyl phosphate, tris (2-ethylhexyl) phosphate, tris (butoxyethyl ) phosphate, tricresyl phosphate, trixylenyl phosphate, 2-ethylhexyl diphenyl phosphate, cresyl di-2 , 6-xylenyl phosphate and CR-733S, CR-741, CR- 747 and PX-200 manufactured by Daihachi Chemical Industry Co . , Ltd. Among these, PX-200 manufactured by Daihachi Chemical Industry Co . , Ltd. is particularly preferable from the viewpoint of low tack. These phosphoric acid ester compounds may be used alone or as a mixture of two or more types .

The content of phosphorous compound (e) in the solid component of the flame-retarding composition for a solder resist is preferably within the range of 2 to 10% by weight . If the content of the phosphorous compound is less than 2% by weight, flame retardation effects are unable to be obtained, while if the content of the phosphorous compound exceeds 10% by weight, the appearance of the cured film may be impaired due to bleedout . 5. Metal Hydrate Compound (E)

The metal hydrate compound (E) .used in the flame- retarding composition for a solder resist of the present invention is a metal compound that has crystalline water, and the amount of bound water per mole as determined by thermal analysis is , for example, within the range of 12 to 60% by weight, although not limited thereto .- A metal hydrate is used that preferably has an amount of absorbed heat during thermal decomposition of 400 J/g or more, and more preferably 600 to 2 , 500 J/g, from the viewpoint of flame retardation effects . Specific examples of such metal hydrates include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, Dawsonite, calcium aluminate, gypsum dehydrate, zinc borate, barium metaborate, zinc hydroxystannic chloride, kaolin and vermiculite . Among these, aluminum hydroxide and magnesium hydroxide are particularly preferable .

Although there are no particular limitations on the particle size of the metal hydrate compound (E) used in the flame-retarding composition for a solder resist of the present invention, the .mean particle diameter is preferably 40 μm or less , and more preferably 2 μm or less . If the mean particle diameter exceeds 40 μm, the transparency of the cured resist film becomes poor resulting in decreased optical transmittance and impaired appearance and smoothness of the coated film surface .

Metal hydrate compounds that have been surface treated by a surface treatment agent having polarity are particularly preferable as metal hydrate compounds used in the present invention . Specific examples of surface treatment agents include silane coupling agents such as epoxy silane, amino silane, vinyl silane and mercapto silane, as well as titanate coupling agents .

The content of the metal hydrate compound in the solid component of the flame-retarding composition for a solder resist is preferably 5 to 30% by weight .

6. Photocurable Monomer or Oligomer (F) A photocurable monomer or oligomer (F) may be added to the flame-retarding composition for a solder resist of the present invention as necessary to increase photosensitivity. The addition of a photocurable monomer or oligomer enables curing to take place at a low level of exposure .

(Meth) acrylates, for examples , can be used for this photocurable monomer or oligomer . Examples of (meth) acrylates include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl

(meth) acrylate and stearyl (meth) acrylate; alicyclic (meth) acrylates such as cyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentyl (meth) acrylate and dicyclopentenyl oxyethyl (meth) acrylate ; aromatic (meth) acrylates such as benzyl (meth) acrylate, phenyl (meth) acrylate, phenyl carbitol (meth) acrylate, nonyl phenyl (meth) acrylate, nonyl phenyl carbitol (meth) acrylate and nonyl phenoxy (meth) acrylate; (meth) acrylates having an amino group such as 2- dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl

(meth) acrylate and 2-tert-butylaminoethyl (meth) acrylate; methacrylates having a phosphorous atom such as methacryloxy ethyl phosphate, bis-methacryloxy ethyl phosphate and methacryloxy ethyl phenyl acid phosphate (Phenyl P) ; diacrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 6- hexanediol di (meth) acrylate and bis-glycidyl (meth) acrylate; polyacrylates such as trimethylol propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate and dipentaerythritol hexa (meth) acrylate; modified polyole polyacrylates such as diacrylates of bisphenol A modified by four moles of ethylene oxide, fatty acid-modified pentaerythritol diacrylate, triacrylates of trimethylol propane modified by three moles of propylene oxide, and triacrylates of trimethylol propane modified by six moles of propylene oxide; polyacrylates having an isocyanuric acid backbone such as bis (acryloyloxyethyl) monohydroxy ethyl isocyanurate, tris (acryloyloxyethyl) isocyanurate and ε-caprolactone-modified tris (acryloyloxyethyl ) isocyanurate; polyester acrylates such as α, ω-diacryloyl- (bisethyleneglycol) -phthalate_. and α, ω-tetraacryloyl- (bistrimethylolpropane) -tetrahydrophthalate; allyl (meth) acrylates ; polycaprolactone (meth) acrylates ; (meth) acryloyloxyethyl phthalates ; (meth) acryloyloxyethyl succinates ; and, phenoxyethyl acrylates . In addition, N- vinyl compounds such as N-vinyl pyrrolidone, N-vinyl formamide and N-vinyl acetoamide, as well as epoxy acrylates and urethane acrylates can also be used . Urethane (meth) acrylate compounds having two or more ethylene unsaturated groups in their molecule are preferable due to their superior photosensitivity. The amount of these photocurable monomers or oligomers used is normally within the range of 0.1 to 30% by weight, preferably 1.0 to 20% by weight, and particularly preferably 3.0 to 15% by weight, in the flame-retarding composition for a solder resist of the present invention . 7. Epoxy Heat Curing Catalyst (G)

An epoxy heat curing catalyst (G) can be used in the flame-retarding composition for a solder resist of the present invention to accelerate curing of the aforementioned epoxy resin . Examples of catalyst that can be used include amines , quaternary ammonium salts, acid anhydrides such as cyclic aliphatic acid anhydrides , aliphatic acid anhydrides and aromatic acid anhydrides, nitrogen-containing heterocyclic compounds such as polyamides , imidazoles and triazine compounds, urea compounds and organometallic compounds .

Examples of amines include aliphatic and aromatic primary, secondary and tertiary amines . Examples of aliphatic amines include polymethylene diamine, polyether diamine, diethylene triamine, triethylene triamine, tetraethylene pentamine, triethylene tetramine, diethyl aminopropyl amine, menthene diamine, aminoethyl ethanol amine, bis (hexamethylene) triamine, 1 , 3, 6-tris- aminomethyl hexane, tributyl amine, 1, 4- diazabicyclo [2 , 2 , 2 ] octane and 1, 8-diazabicyclo [5 , 4 , 0 ] undecen-7-ene . Examples of aromatic amines include metaphenylene diamine, diaminodiphenyl methane, diaminodiphonyl methane, diaminodiphenyl sulfone and benzyl dimethyl diamine . Examples of quaternary ammonium salts include quaternary ammonium salts and quaternary alkyl amino propyl amines comprising tetrabutyl ammonium ions, tetrahexyl ammonium ions , dihexyl dimethyl ammonium ions , 'dioctyl dimethyl ammonium ions, hexatrimethyl ammonium ions, octatrimethyl ammonium ions , dodecyl trimethyl ammonium ions, hexadecyl trimethyl ammonium ions, stearyl trimethyl ammonium ions , dococenyl trimethyl ammonium ions, cetyl trimethyl ammonium ions , cetyl triethyl ammonium ions , hexadecyl ammonium ions , tetradecyl dimethyl benzyl ammonium ions, stearyl ^"dimethyl benzyl ammonium ions, dioleyl dimethyl ammonium ions , N-methyl diethanol lauryl ammonium ions, dipropanol monomethyl lauryl ammonium ions , dimethyl monoethanol lauryl ammonium ions and polyoxyethylene dodecyl monomethyl ammonium ions .

Examples of acid anhydrides include aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis (anhydrotrimellitate) and glycerol tris (anhydrotrimellitate) , and maleic anhydride, succinic anhydride, methyl naj ic anhydride, hexahydrophathalic anhydride, tetrahydrophthalic anhydride, polyadipic anhydride, chlorendic anhydride and tetrabromophthalic anhydride . Examples of polyamides include polyamino amides having primary and secondary amino groups obtained by a condensation reaction of a polyamine such as diethylene triamine or triethylene tetramine with a dimer acid.

Specific examples of imidazoles include imidazole, 2-ethyl-4-methyl imidazole, N-benzyl-2-methyl imidazole, l-cyanoethyl-2-undecyl imidazolium trimellitate and 2- methyl imidazolium isocyanurate .

Triazine compounds are compounds having a six-member ring that contains three nitrogen atoms, examples of which include melamine compounds, cyanuric acid compounds and melamine cyanurate compounds . Specific examples of melamine compounds include melamine, N-ethyl melamine and N, N ' , N"-triphenyl melamine . Specific examples of cyanuric acid compounds include cyanuric acid, ^■isocyanuric acid, trimethyl cyanurate, tris-methyl isocyanurate, triethyl cyanurate, tris-ethyl isocyanurate, tri (n-propyl) cyanurate, tris (n-propyl) isocyanurate, diethyl cyanurate, N, N ' -diethyl isocyanurate, methyl cyanurate and methyl isocyanurate . Examples of melamine cyanurate compounds include equimolar reaction products of melamine compounds and cyanuric acid compounds . Examples of urea compounds include toluene bis (dimethylurea) , 4 , 4 ' -methylene bis (phenyldimethylurea) and phenyl dimethylurea .

Examples of organometallic compounds include organic acid metal salts, 1, 3-diketone metal complexes and metal alkoxides . Specific examples include organic acid metal salts such as dibutyl tin dilaurate, dibutyl tin maleate and zinc 2-ethylhexaoic acid, 1 , 3-diketone metal complexes such as nickel acetyl acetonate and zinc acetyl acetonate, and metal alkoxides such as titanium tetrabutoxide, zirconium tetrabutoxide and aluminum 5 tetrabutoxide .

The amount of these epoxy heat curing catalysts used is- normally less than 1% by weight, preferably 0.9% by weight or less, more preferably 0.8% by weight or less , and even more preferably 0.7% by weight or less, in the 0 flame-retarding composition for a solder resist of the present invention . 8. Other Additives i An organic solvent may be added to a flame-retarding composition for a solder resist of the present invention 5 for the purpose of adjusting viscosity and so forth as necessary. Adj usting viscosity facilitates coating or printing onto an obj ect by roller coating, spin coating, screen coating or curtain coating and so forth . 8-1. Organic Solvents 0 Examples of organic solvents include isopropanol, 1- butanol, toluene, xylene, ethyl benzene, cyclohexane, isophorone, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, propylene glycol 5 monomethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, ethyl acetate, isoamyl acetate, ethyl 0 lactate, acetone, methyl ethyl ketone, cyclohexanone, N, N-dimethylformamide and N-methyl pyrrolidone . These may be used alone or as a combination of two or more types .

The amount of organic solvent used is preferably 5 adj usted so that the viscosity of the flame-retarding composition for a solder resist is 500 to 500 , 000 mPa - s (value measured at 25⁰C using a Brookfield viscometer) . The viscosity is more preferably 1, 000 to 500 , 000 mPa ^• s . If the viscosity is within this range, it is suitable for coating or printing onto an obj ect and facilitates ease of use . In addition, the amount of organic solvent used to achieve this viscosity is 50% by weight or less in the flame-retarding composition for a solder resist . If the amount of organic solvent used exceeds 50% by weight, the concentration of the solid component becomes low, and in the case of printing this flame-retarding composition for a solder resist onto a board and so forth, an adequate film thickness is unable to be obtained with a single printing, and numerous printings may be required. 8-2. Colorant

A colorant can be used as necessary in a flame- retarding composition for a solder resist of the present invention . There are no particular limitations on the colorant, and examples include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black and naphthalene black . 8-3. Others

Additives such as thermopolymerization inhibitors, thickeners, antifoaming agents, leveling agents and adhesive agents can be added as necessary to the flame- retarding composition for a solder resist of the present invention. Examples of thermopolymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, tert-butyl catechol, pyrogallol, phenothiazine, triethylene glycol- bis [3- (3-t-butyl-5-methyl-4- hydroxyphenyl ) propionate] and pentaerythritol- te.traquis [3- ( 3, 5-di-t-butyl-4- hydroxyphenyl) propionate . Examples of thickeners include layered silicates such as hectorite, montmorillonite, saponite, hyderite, stevensite, tetrasilicone mica and teniorite, interlayer compounds in which these compounds are treated with organic cations, silica and organic silica, bobal and cellulose derivatives . Antifoaming agents are used to eliminate foam that forms during coating and curing, specific examples of which include acrylic and silicone- based surfactants . Leveling agents are used to eliminate unevenness in coating surfaces that form during printing and coating, specific examples of which include acrylic and silicone-based surfactants . Examples of adhesion agents include imidazole-based, thiazole-based, triazole- based and silane coupling agents . In addition, other additives can be added within a range that does not impair the obj ect of the present invention, examples of which include ultraviolet absorbers for storage stability and plasticizers .

9. Production Process of Flame-Retarding Composition for a Solder Resist A flame-retarding composition for a solder resist of the present invention can be produced by mixing the aforementioned components using an ordinary method. There are no particular limitations on the mixing method. Some of the components may be mixed followed by mixing in the remaining components , or all of the components may be mixed all at once . More specifically, after mixing each of the aforementioned components , the composition is produced using a known kneading method with a kneader, 'three-roll mill or bead mill . 10. Cured Products and Use of Flame-Retarding Composition for a Solder Resist A cured product can be obtained from a flame- retarding composition for a solder resist of the present invention by coating onto a board and so forth at a suitable thickness , heat treating and drying followed by exposure, development and heat curing . Although a flame- retarding photosensitive composition of the present invention can be used in various applications, since it has heat resistance, hardness, dimensional stability and flexibility, and allows the formation of a cured film that is resistant to the occurrence of warping deformation, it is suited for use as an insulating protective coating of a printed circuit board, and is particularly suited for use as an insulating protective coating of an FPC board. In the case of forming an insulating protective coating, after coating the photosensitive composition onto the board on which a circuit has been formed at a thickness of 10 to 100 μm, it is heat-treated for about 1 to 30 minutes within a temperature range of 50 to 120⁰C to dry followed by exposing through a negative mask formed to a desired exposure pattern, developing and removing the unexposed portion with an alkaline developing solution, and heat- curing for about 20 to 60 minutes within a temperature range of 100 to 180°C . Furthermore, a flame-retarding photosensitive composition of the present invention may also be used as , for example, an interlayer insulating resin layer of a multilayer printed circuit board.

Activating light emitted from a known activating light source such as a carbon arc lamp, mercury vapor arc lamp or xenon arc lamp is used for the activating light used for exposure . Since the sensitivity of photopolymerization initiator (B) contained in the photosensitive layer is normally the greatest in the ultraviolet range, the activating light source preferably effectively radiates ultraviolet light in that case . Naturally, in the case photopolymerization initiator (B) is sensitive to visible light such as in the case of 9, 10-phenanthracene quinone, visible light is used for the activating light, and a photographic flood lamp or solar lamp and so forth other than the aforementioned activating light sources is used for the light source . In addition, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate or potassium carbonate can be used for the developing solution . This type of flame-retarding composition simultaneously satisfies performance requirements relating to the formation of a photosensitive coating such as low tack, photosensitivity and ease of development, as well as performance requirements of an insulating protective coating such as flame resistance, HHBT resistance and PCT resistance, while also allowing the formation of a flexible cured film. Since the bisphenol A epoxy resin (a) represented by general formula ( I ) in particular is used, a flame-retarding composition for a solder resist having low tack and flexibility is optimum for use as an insulating protective film of a thin circuit board such as a flexible printed circuit board.

A cured product of a flame-retarding composition for a solder resist of the present invention is optimum for electronic component applications requiring a high level of durability in particular . Examples

Although the following provides a more detailed explanation of the present invention through synthesis examples, examples and comparative examples, the present invention is not limited to these examples . Furthermore, the term "parts" in the examples is always based on weight unless specifically indicated otherwise . 'Synthesis of unsaturated Group-Containing Polycarboxylic Acid Resin (A)

Synthesis Example 1 (A-I )

After dissolving 400 parts of bisphenol F solid epoxy resin (Nippon Kayaku, epoxy equivalent : 800 , mean value of n in formula ( 1 ) : 5.8 ) in 925 parts of epichlorhydrin and 462.5 parts of dimethylsulfoxide, 13.0 parts of 98.5% NaOH were added over the course of 100 minutes at 70⁰C while stirring . Following addition, the reaction was additionally carried out for 3 hours at 70⁰C . Next, the maj ority of the excess unreacted epichlorhydrin and dimethylsulfoxide were distilled off under reduced pressure, and the reaction product containing byproduct salts and dimethylsulfoxide was dissolved in 750 parts of methyl isobutyl ketone followed by the addition of 10 parts of 30% NaOH and reacting for 1 hour at 70°C . Following completion of the reaction, the reaction product was washed twice with 200 parts of water . After separating the oily and aqueous phases , the methyl isobutyl ketone was recovered from the oily layer by distillation to obtain 370 parts of an epoxy resin (a-1) having an epoxy equivalent of 536. When calculated from the epoxy equivalent, about 1.1 of the 5.8 alcoholic hydroxyl groups in the resulting epoxy resin (a-1 ) were determined to have been epoxified. Namely, 19% of Y in formula ( I ) were 2 , 3-epoxypropyl groups .

5360 parts ( 10 equivalents ) of the epoxy resin (a-1 ) obtained above, 720 parts ( 10 equivalents ) of acrylic acid, 3.4 parts of methyl hydroquinone and 3274 parts of carbitol acetate were combined followed by heating to 90°C and stirring to dissolve the reaction mixture . Next, the reaction liquid was cooled to 60°C followed by the addition of 22.8 parts of triphenyl phosphine, heating to 100°C and reacting for about 32 hours to obtain a reaction product having an acid value of 1.0 mgKOH/g . Next, 2265 parts ( 14.9 moles ) of tetrahydrophthalic anhydride and 1219 parts of carbitol acetate were added to the reaction product followed by heating to 95°C, allowing to react for about 6 hours and cooling to obtain a carboxyl-group containing photocurable resin (A-I ) in which the concentration of the solid component having an acid value of 100 mgKOH/g was 65% . The viscosity (25°C) of this resin (A-I ) was 31.3 Pa - s . Synthesis Example 2 (A-2 )

After dissolving 400 parts of bisphenol F solid epoxy resin (Nippon Kayaku, epoxy equivalent : 800 , mean value of n in formula ( 1) : 5.8 ) in 925 parts of epichlorhydrin and 462.5 parts of dimethylsulfoxide, 42.3 parts of 98.5% NaOH were added over the course of 100 minutes at 70°C while stirring . Following addition, the reaction was additionally carried out for 3 hours at 70°C . Next, the maj ority of the excess unreacted epichlorhydrin and dimethylsulfoxide were distilled off under reduced pressure, and the reaction product containing byproduct salts and dimethylsulfoxide was dissolved in 750 parts of methyl isobutyl ketone followed by the addition of 10 parts of 30% NaOH and reacting for 1 hour at 70°C . Following completion of the reaction, the reaction product was washed twice with 200 parts of water . After separating the oily and aqueous phases , the methyl isobutyl ketone was recovered from the oily layer by distillation to obtain 385 parts of an epoxy resin (a-2 ) having an epoxy equivalent of 354. When calculated from the epoxy equivalent, about 3.0 of the 5.8 alcoholic hydroxyl groups in the resulting epoxy resin (a-2 ) were determined to have been epoxified. Namely, 52% of Y in formula ( I ) were 2 , 3-epoxypropyl groups .

3548 parts ( 10 equivalents) of the epoxy resin (a-2) obtained above, 720 parts ( 10 equivalents ) of acrylic acid, 3.4 parts of methyl hydroquinone and 2294 parts of carbitol acetate were combined followed by heating to 9O⁰C and stirring to dissolve the reaction mixture . Next, the reaction liquid was cooled to 60°C followed by the addition of 22.8 parts of triphenyl phosphine, heating to 100°C and reacting for about 32 hours to obtain a reaction product having an acid value of 1.0 mgKOH/g . Next, 1839 parts ( 12.1 moles ) of tetrahydrophthalic anhydride and 990 parts of carbitol acetate were added to the reaction product followed by heating to 95°C, allowing to react for about 6 hours and cooling to obtain a carboxyl-group containing photocurable resin (A-2 ) in which the concentration of the solid component having an acid value of 100 mgKOH/g was 65% . The viscosity (25°C) of this resin (A-2 ) was 32.5 Pa * s . Synthesis Example 3 (A-3)

After dissolving 400 parts of bisphenol F solid epoxy resin (Nippon Kayaku, epoxy equivalent : 800, mean value of n in formula ( 1 ) : 5.8 ) in 925 parts of epichlorhydrin and 462.5 parts of dimethylsulfoxide, 47.1 parts of 98.5% NaOH were added over the course of 100 minutes at 70°C while stirring . Following addition, the reaction was additionally carried out for 3 hours at 70°C . Next, the maj ority of the excess unreacted epichlorhydrin and dimethylsulfoxide were distilled off under reduced pressure, and the reaction product containing byproduct salts and dimethylsulfoxide was dissolved in 750 parts of methyl isobutyl ketone followed by the addition of 10 parts of 30% NaOH and reacting for 1 hour at 70°C . Following completion of the reaction, the reaction product was washed twice with 200 parts of water . After separating the oily and aqueous phases, the methyl isobutyl ketone was recovered from the oily layer by distillation to obtain 390 parts of an epoxy resin (a-3 ) having an epoxy equivalent of 300. When calculated from the epoxy equivalent, about 4.1 of the 5.8 alcoholic hydroxyl groups in the resulting epoxy resin (a-3 ) were determined to have been epoxified . Namely, 71% of Y in formula ( I ) were 2 , 3-epoxypropyl groups .

3000 parts (10 equivalents) of the epoxy resin (a-3) obtained above, 720 parts ( 10 equivalents) of acrylic acid, 3.4 parts of methyl hydroquinone and 2003 parts of carbitol acetate were combined followed by heating to 90°C and stirring to dissolve the reaction mixture . Next, the reaction liquid was cooled to 60°C followed by the addition of 22.8 parts of triphenyl phosphine, heating to 100°C and reacting for about 32 hours to obtain a reaction product having an acid value of 1.0 mgKOH/g . Next, 1386 parts ( 9.12 moles) of tetrahydrophthalic anhydride and 746 parts of carbitol acetate were added to the reaction product followed by heating to 95°C, allowing to react for about 6 hours and cooling to obtain a carboxyl-group containing photocurable resin (A-3 ) in which the concentration of the solid component having an acid value of 100 mgKOH/g was 65% . The viscosity (25°C) of this resin (A-3 ) was 35.0 Pa - s . Synthesis Example 4 (A-4 ) 4220 parts ( 10 equivalents ) of the epoxy resin (a-2 ) obtained above, 720 parts (10 equivalents) of acrylic acid, 3.4 parts of methyl hydroquinone and 2674 parts of carbitol acetate were combined followed by heating to 9O⁰C and stirring to dissolve the reaction mixture . Next, the reaction liquid was cooled to 60°C followed by the addition of 22.8 parts of triphenyl phosphine, heating to 100°C and reacting for about 32 hours to obtain a reaction product having an acid value of 1.0 mgKOH/g . Next, 1080 parts (10.8 moles) of succinic anhydride and 581.5 parts of carbitol acetate were added to the reaction product followed by heating to 95⁰C, allowing to react for about 6 hours and cooling to obtain a carboxyl-group containing photocurable resin (A-4 ) in which the concentration of the solid component having an acid value of 100 mgKOH/g was 65% . The viscosity (25°C) of this resin (A-4 ) was 46.0 Pa - s . Synthesis Example 5 (A-5)

After dissolving 400 parts of bisphenol F solid epoxy resin (Nippon Kayaku, epoxy equivalent : 800, mean value of n in formula ( 1 ) : 5.8 ) in 925 parts of epichlorhydrin and 462.5 parts of dimethylsulfoxide, 81.2 parts of 98.5% NaOH were added over the course of 100 minutes at 70⁰C while stirring . Following addition, the reaction was additionally carried out for 3 hours at 70⁰C . Next, the maj ority of the excess unreacted epichlorhydrin and dimethylsulfoxide were distilled off under reduced pressure, and the reaction product containing byproduct salts and dimethylsulfoxide was dissolved in 750 parts of methyl isobutyl ketone followed by the addition of 10 parts of 30% NaOH and reacting for 1 hour at 70⁰C . Following completion of the reaction, the reaction product was washed twice with 200 parts of water . After separating the oily and aqueous phases, the methyl isobutyl ketone was recovered from the oily layer by distillation to obtain 370 parts of an epoxy resin (a-5 ) having an epoxy equivalent of 290. When calculated from the epoxy equivalent, about 5.2 of the 5.8 alcoholic hydroxyl groups in the resulting epoxy resin (a-5) were determined to have been epoxified. Namely, 90% of Y in formula ( I ) were 2 , 3-epoxypropyl groups . 2900 parts (10 equivalents) of the epoxy resin (a-5) obtained above, 720 parts ( 10 equivalents ) of acrylic acid, 3.4 parts of methyl hydroquinone and 1949 parts of carbitol acetate were combined followed by heating to 90°C and stirring to dissolve the reaction mixture . Next, the reaction liquid was cooled to 60°C followed by the addition of 22.8 parts of triphenyl phosphine, heating to 100°C and reacting for about 32 hours to obtain a reaction product having an acid value of 1.0 mgKOH/g . Next, 1349 parts ( 8.87 moles ) of tetrahydrophthalic anhydride and 727 parts of carbitol acetate were added to the reaction product followed by heating to 95⁰C, allowing to react for about 6 hours and cooling to obtain a carboxyl-group containing photocurable resin (A-5 ) in which the concentration of the solid component having an acid value of 100 mgKOH/g was 65% . The viscosity (25°C) of this resin (A-5 ) was 78.0 Pa ^« s . Synthesis Example 6 (A-6)

8000 parts ( 10 equivalents) of bisphenol F solid epoxy resin (Nippon Kayaku, epoxy equivalent : 800 , mean value of n in formula (1) : 5.8 ) , 720 parts (10 equivalents ) of acrylic acid, 3.4 parts of methyl hydroquinone and 4695 parts of carbitol acetate were combined followed by heating to 90°C and stirring to dissolve the reaction mixture . Next, the reaction liquid was cooled to 60⁰C followed by the addition of 22.8 parts of triphenyl phosphine, heating to 100⁰C and reacting for about 32 hours to obtain a reaction product having an acid value of 1.0 mgKOH/g . Next, 3248 parts (21.37 moles ) of tetrahydrophthalic anhydride and 1749 parts of carbitol acetate were added to the reaction product followed by heating to 95°C, allowing to react for about 6 hours and cooling to obtain a carboxyl-group containing photocurable resin (A-6) in which the concentration of the solid component having an acid value of 100 mgKOH/g was 65% . The viscosity (25°C) of this resin (A-6) was 32.0 Pa - s .

Examples 1-5 and Comparative Examples 1-4 ( Preparation of Flame-Retarding Compositions for a Solder Resist)

After blending each of the components at the ratios (percent by weight) indicated in the following Table 1, the principal agent and curing agent were prepared by passing three times through a three-roll mill . Furthermore, during preparation with the three-roll mill, a solvent in the form of a mixture of carbitol acetate and petroleum naphtha (mixing ratio : 60/40% by weight) was added so that the concentration of the solid component of the principal agent was 71% by weight and that of the curing agent was 80% by weight .

The following evaluations were carried out on each of the resulting flame-retarding compositions . <Preparation of Laminated Test Pieces>

An ink consisting of a mixture of the principal agent and curing agent was screen-printed onto a board with a 100 mesh polyester screen . The printed board was placed in a hot air circulating dryer at 70°C and dried for 30 minutes . Furthermore, the following boards ( 1) arid (2) were used as evaluation boards .

( 1 ) Boards obtained by washing a printed board composed of polyimide film (thickness : 25 μm) laminated on one side of a copper foil (thickness : 12 μm) (Upicell (registered trademark) N, ϋbe Industries ) with 10% aqueous ammonium sulfate solution followed by rinsing and drying with flowing air .

(2 ) Polyimide film having a thickness of 25 μm (Capton (registered trademark) 10OH, Toray-Dupont)

<Exposure, Development and Heat Curing of Laminated Test Pieces>

Each of the resulting laminated test pieces was exposed at 500 mJ/cm² using the HMW-680GW Exposure Unit (ORC Manufacturing Co . , Ltd. ) . Next, the unexposed portion was removed by spraying for 60 seconds with a 1% by weight aqueous sodium carbonate solution at a temperature of 30°C and spraying pressure of 0.2 MPa followed by spraying for 60 seconds with water at a temperature of 30°C and spraying pressure of 0.15 MPa . This was followed by heat treatment for 60 minutes at 15O⁰C to obtain FPC laminated boards (used for Evaluation Board ( I) ) and polyimide laminated boards (used for Evaluation Board (2 ) ) . Furthermore, when preparing samples for evaluation of photosensitivity, the samples were exposed using the Hitachi 21-Step Tablet as a negative pattern . When preparing samples for evaluation of soldering heat resistance, samples were used in which copper foil remained in a square shape measuring 1 cm x 1 cm over a range of 4 cm x 6 cm and at 1 mm/1 mm (line/space) over a length of 2 cm as the negative pattern . A negative pattern was not used during preparation of other evaluation samples . <Evaluation of Physical Properties>

Physical properties were evaluated in the manner described below . Those results are shown in the following Table 1. In addition, among the following evaluated parameters, "flammability" and "flexibility" were evaluated using the polyimide laminated boards, while other evaluated parameters were evaluated using FPC boards .

[Evaluated Parameters] Flammability

Flammability test pieces were fabricated in the manner described below . Ink consisting of a mixture of principal agent and curing agent was screen-printed on one side of a polyimide film having a thickness of 25 μm and measuring 200 mm x 50 mm (Toray-Dupont, Capton 100H) using a 100 mesh polyester screen . The printed film was placed in a hot air circulating dryer at 70°C and dried for 30 minutes . Next, ink was then similarly printed onto the other side of the test piece, and the test piece was dried for 30 minutes by placing in a hot air circulating dryer at 70°C. After irradiating with UV light at 500 mJ/cm², the test piece was heat-cured for 60 minutes at 150°C . The test piece was used for the flammability test after adjusting status by allowing to stand at a temperature of 23⁰C and relative humidity of 50% for 48 hours . Flammability characteristics were evaluated using a method complying with the test of

Flammability Test Standard 94UL-VTM for Polymer Materials of the US Underwriters Laboratories, Inc . (UL) .

Furthermore, the classifications of "VTM" and "NOT" in Table 1 are based on the following standards . "VTM-O" : Satisfies all of the following requirements :

(1) None of the test pieces burn with a flame beyond 10 seconds after discontinuation of each contact with the flame . (2 ) The total duration of burning with a flame after five test pieces of each group are contacted with the flame a total of 10 times does not exceed 50 seconds .

(3) Burning with a flame or burning red hot does not reach the 125 mm marked line .

(4 ) Absorbent cotton is not ignited by dropping burning material .

(5) The total duration of burning with a flame or burning red hot of each sample after discontinuing the second contact with the flame does not exceed 30 seconds .

( 6) When only one of the five test pieces of each group does not satisfy the requirements, or when the total duration of burning with a flame is within the range of 51 to 55 seconds, five more test pieces are additionally tested, and all must satisfy the requirements of ( 1) to (5) . "VTM-I" : Satisfies all of the following requirements :

(1) None of the test pieces burn with a flame beyond 30 seconds after discontinuation of each contact with the flame .

(2) The total duration of burning with a flame after five test pieces of each group are contacted with the flame a total of 10 times does not exceed 250 seconds .

(4 ) Absorbent cotton is not ignited by dropping burning material . (5) The total duration of burning with a flame or burning red hot of each sample after discontinuing the second contact with the flame does not exceed 60 seconds .

( 6) When only one of the five test pieces of each group does not satisfy the requirements, or when the total duration of burning with a flame is within the range of 251 to 255 seconds, five more test pieces are additionally tested, and all must satisfy the requirements of (1) to (5) . "VTM-2" : Satisfies all of the following requirements : (1) None of the test pieces burn with a flame beyond 30 seconds after discontinuation of each contact with the flame .

(3 ) Burning with a flame or burning red hot does not reach the 125 mm marked line .

(4 ) Absorbent cotton may be ignited by dropping burning material .

(5) The total duration of burning with a flame or burning red hot of each sample after discontinuing the second contact with the flame does not exceed 60 seconds . ( 6) When only one of the five test pieces of each group does not satisfy the requirements, or when the total duration of burning with a flame is within the range of 251 to 255 seconds, five more test pieces are additionally tested, and all must satisfy the requirements of (1) to (5) .

"NOT" : Not applicable .to any of the above classes . Tack

Tack of the photosensitive surface was evaluated at 'room temperature according to the following criteria using test pieces obtained by printing the flame- retarding composition for a solder resist onto an FPC board, drying for 30 minutes at 7O⁰C and then cooling for 30 minutes .

A: No sticking whatsoever B: Slight sticking C: Sticking

Photosensitivity

Photosensitivity of a curable flame-retarding composition was evaluated by measuring the number of steps of the step tablet of a photocurable film formed on an FPC laminated board obtained after layering a negative pattern in the form of a Hitachi 21 Step Tablet onto the sample, exposing (500 mJ/cm²) and developing. Photosensitivity was indicated as the number of steps of the step tablet, and the greater the number of steps of the step tablet, the higher the photosensitivity. Ease of Development

An FPC laminated board, obtained by printing a solder resist flame-retarding composition and drying, was developed for 1 minute under conditions of a temperature of 30°C and spraying pressure of 0.2 MPa using 1% by weight aqueous sodium carbonate solution for the developing solution, and then rinsed for 1 minute with water under conditions of a spraying pressure of 0.2 MPa followed by visual evaluation of the amount of board remaining after development . The abbreviations used in Table 1 are indicated below . A: Able to be developed C : Portions remained after development Flexibility A polyimide laminated board was bent for 1 minute at a pressure of 0.5 MPa to an angle of 180 degrees with the cured film composed of the photosensitive layer on the outside . The presence of cracks in the cured film was ^'investigated with a light microscope at a magnification of 3OX .

A: No cracks in the cured film C : Cracks in the cured film Soldering Heat Resistance

Rosin flux was coated onto an FPC laminated board and floated for 5 seconds in a solder bath at 260°C in compliance with the test method of JIS C-6481. With this constituting one cycle of testing, soldering heat resistance was represented with the maximum number of cycles when testing was repeated while visually confirming that there are no changes in the cured film along with the absence of blistering and solder penetration for each cycle . PCT Resistance

An FPC laminated board on which a resist coating was formed according to the previously described conditions was treated for 96 hours under conditions of 121°C and 0.2 MPa using a PCT system (Tabai, ESPEC HAST CHAMBER EHS-

411M) followed by evaluation of the status of the cured coating .

A: No cracking, discoloration or elution B : Some cracking, discoloration and elution C : Considerable cracking, discoloration and elution

[Table 1]

u>

*1) Kayacure DETX-S : 2, 4-diethylthioxanthone (Nippon Kayaku)

*2) Irgacure 907 : 2-methyl- [4- (methylthio) phenyl] -2- itιorpholino-1-propanone (Ciba Specialty

Chemicals)

*3) PX-200 : Aromatic condensed phosphoric acid ester (Daihachi Chemical Industry)

*4 ) Higilite H43M: Aluminum hydroxide (Showa Denko)

*5) Aerosil #200 : Silicon dioxide (Nippon Aerosil)

*6) Fluorene A0-40H: Antifoaming agent (Kyoeisha Chemical)

*7 ) EPPN-502H: Salicyl aldehyde epoxy resin (Nippon Kayaku, epoxy equivalent : 170)

*8 ) Epicoat 828 : Bisphenol A epoxy resin (Japan Epoxy Resin, epoxy equivalent : 185 )

*9) Epicoat TBBA5050 : Brominated bisphenol A epoxy resin (Japan Epoxy Resin, bromine content :

49% by weight, epoxy equivalent : 390 )

*10 ) EB1290K: Urethane acrylate (Daicel Chemical Industries)

*11) Kayarad DPCA-60 : Caprolactone-modified dipentaerythritol hexaacrylate (Nippon Kayaku) ,

*12 ) Curezol 2P4MHZ-PW: 4-phenyl-5-hydroxymethyl imidazole (Shikoku) *>

Effect of the Invention

A flame-retarding composition for a solder resist of the present invention has alkaline developing properties and is able to form a protective film that is provided with low tack, flame retardation, PCT resistance, soldering heat resistance and flexibility. Thus , a flame-retarding composition for a solder resist of the present invention can be preferably used for forming a solder resist for FPC in particular .

Claims

1. A flame-retarding composition for a solder resist comprising : an unsaturated group-containing polycarboxylic acid resin (A) , wherein a polybasic acid > anhydride (c) is added to the reaction product of a bisphenol epoxy resin (a) represented with the following general formula ( I ) :

(wherein, n represents an integer of 0 to 10 , X is selected from a methylene group, ethylidene group, isopropylidene group, sulfonyi group and single bond, and Y represents a hydrogen atom or a 2 , 3-epoxypropyl group) with an unsaturated group-containing monocarboxylic acid (b) , a photoinitiator (B) , an epoxy resin (C) , a flame retardant ( D) and a metal hydrate compound (E) .

2. A flame-retarding composition for a solder resist as set forth in claim 1, wherein 10 to 84% of Y in the bisphenol epoxy resin (a) represented by general ^■formula ( I ) is a 2 , 3-epoxypropyl group .

3. A flame-retarding composition for a solder resist as set forth in claim 1 , wherein the polybasic acid anhydride (c) is an anhydride of a polybasic acid selected from phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, and methyl endomethylene tetrahydrophthalic anhydride .

4. A flame-retarding composition for a solder resist as set forth in claim 1 , wherein the acid value of the solid component of the unsaturated group-containing polycarboxylic acid resin (A) is 50 to 140 mgKOH/g .

5. A flame-retarding composition for a solder resist as set forth in claim 1, wherein the flame retardant (D) is a brominated epoxy resin (d) and/or phosphorous compound (e) .

6. A flame-retarding composition for a solder resist as set forth in claim 5, wherein the brominated epoxy resin (d) is a brominated bisphenol A epoxy resin .

7. A flame-retarding composition for a solder resist as set forth in claim 6, wherein the content of the brominated epoxy resin (d) in the solid component of the flame-retarding composition for a solid resist is within the range of 4 to 13% by weight in terms of the bromine content .

8. A flame-retarding composition for a solder resist as set forth in claim 5, wherein the phosphorous compound (e) is a phosphoric acid ester .

9. A flame-retarding composition for a solder resist as set forth in claim 5, wherein the content of the phosphorous compound (e) in the solid component of the flame-retarding composition for a solder resist is within the range of 2 to 10% by weight .

10. A flame-retarding composition for a solder resist as set forth in claim 1, wherein the amount of heat absorbed during thermal decomposition of the metal hydrate compound (E) is 400 to 2, 500 J/g.

11. A flame-retarding composition for a solder resist as set forth in claim 1, wherein the metal hydrate compound (E) is aluminum hydroxide and/or magnesium hydroxide .

12. A flame-retarding composition for a solder resist as set forth in claim 1, wherein the content of the metal hydrate compound (E) in the solid component of the flame-retarding composition for a solder resist is within the range of 5 to 30% by weight .

13. A flame-retarding composition for a solder resist as set forth in claim 5, wherein the equivalent of epoxy groups contained in the epoxy resin (C) and the brominated epoxy resin (d) is within the range of 0.5 to 3.0 (functional group equivalent ratio) relative to the equivalent of carboxyl groups in the flame-retarding composition for a solder resist .

14. A flame-retarding composition for a solder resist as set forth in claim 1 further comprising a photocurable monomer and/or oligomer (F) .

15. A flame-retarding composition for a solder resist as set forth in claim 1 or claim 14 further comprising an epoxy heat curing catalyst (G) .

16. A flame-retarding composition for a solder resist as set forth in claim 1, wherein the viscosity is 500 to 500 , 000 mPa - s (25°C) .

17. A cured product of a flame-retarding composition for a solder resist as set forth in claim 1.

18. A flame-retarding composition for a solder resist as set forth in claim 1, wherein the flame retardation in accordance with UL94VTM standards of a laminate having a cured layer of the flame-retarding composition for a solder resist of 10 to 45 μm each on both sides of a polyimide board having a thickness of 10 to 80 μm satisfies the criteria of VTM-O .

19. A method for curing a flame-retarding composition for a solder resist comprising a step in which, after coating a flame-retarding composition for a solder resist as set forth in claim 1 onto a board, it is dried for 2 to 90 minutes at a temperature range of 50 to 120°C to a thickness of 5 to 80 μm followed by exposure, development and heat curing .

20. An insulating protective coating produced from a flame-retarding composition for a solder resist as set forth in claim 1.

21. A printed circuit board partially or entirely coated with the cured product as set forth in claim 17.

22. A flexible printed circuit board partially or entirely coated with the cured product as set forth in claim 17.

23. An electronic component containing the cured product as set forth in claim 17.