JPH09311446A - Photosensitive resin composition, photosensitive laminated body and production of flexible printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive resin compsn. excellent in sensitivity and photosetting property, capable of efficiently forming a pattern by photolithography and ensuring superior deposition resistance, heat resistance to soldering, solvent resistance, adhesion, flame retardancy and coating work efficiency on a film by using specified epoxy blocked polyamide resin. SOLUTION: This photosensitive resin compsn. contains epoxy blocked polyamide resin, a photopolymerizable unsatd. compd. having an ethylenic unsatd. group at a terminal and a photopolymn. initiator forming free radicals when irradiated with active light as essential components. The epoxy blocked polyamide resin is obtd. by allowing polycarboxylic acids essentially including polytetramethylene glycol modified dicarboxylic acid to react with a diisocyanate in an equiv. ratio of >1, allowing the resultant carboxylic acid- contg. polyamide resin to react with epoxy resin in an equiv. ratio of >=1 and then allowing the resultant epoxy-contg. polyamide resin to react with monocarboxylic acid in an equiv. ratio of >=1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photosensitive resin composition, a photosensitive laminate using the same, and a method for producing a flexible printed board.

[0002]

2. Description of the Related Art Conventionally, a cover lay for punching a polyimide film with a die and thermocompression bonding or a cover coat for screen-printing an ink of a polyimide resin has been used for protecting an outer layer circuit of a flexible printed board. In the case of, there is a limit to the miniaturization of the punching pattern, and it cannot be applied to the solder dam between the QFP pads which has a narrow pitch.
Further, there is a limit to the positional accuracy at the time of laminating, and it is necessary to design a circuit in consideration of the positional deviation margin. Therefore, there is a problem that the flexible printed board cannot be made high in density and miniaturized. Further, in the latter case, there is a limit to pattern miniaturization due to screen printing, and there is a problem that workability is poor.

As a method for solving these problems, a layer of a photosensitive resin composition comprising various polyamic acids (polyimide precursors), an ethylenically unsaturated group-containing photocrosslinking agent and a photopolymerization initiator is formed on a flexible printed board. A method of forming a cover lay having a fine pattern on the surface by exposing, developing and heating is disclosed in JP-A-64-2037 and JP-A-64-2037.
-484893, JP-A-5-158237 and JP-A-6-298935. However, from the viewpoint of light transmittance, a sufficient thickness required for the coverlay cannot be secured, and a step of heating at a high temperature of 250 ° C. or higher is required in order to finally ring-close the polyamic acid to form a polyimide skeleton. However, there are problems such as oxidation of the resin, deterioration of the adhesive layer and warpage of the substrate.

A cover layer having a two-layer structure of thermoplastic polyimide and non-thermoplastic polyimide is formed on a flexible printed board by thermocompression bonding, a resist pattern is formed on the cover layer by pattern printing, and the cover layer is patterned by alkali etching. The method described in JP-A-5-183260 discloses that a two-layer type film of a polyamic acid (polyimide precursor) layer and a photosensitive resin layer is laminated on a flexible printed board, and first, the photosensitive resin layer is exposed and developed. JP-A-5-254064 proposes a method in which a photosensitive resin layer is used as an etching resist after the pattern is formed, and then the polyamic acid layer is patterned by alkali etching. However, in the former method, there is a limit to the miniaturization of the pattern due to screen printing, and the workability is poor, and there is a problem that the cost is high because of the polyimide film having a two-layer structure. In the latter method, so-called wet lamination occurs. There is a problem in workability, such as the necessity of two development processes of the photosensitive resin layer and the polyamic acid layer, and moreover, in order to finally ring-close the polyamic acid into a polyimide skeleton, the temperature should be 250 ° C or higher. A step of heating to a high temperature is required, and there are problems such as oxidation of the copper circuit, deterioration of the adhesive layer, and warpage of the substrate.

On the other hand, there is disclosed a method for producing a flexible printed board using an acrylic resin type photosensitive film as a cover lay, which has been the mainstream in the conventional printed wiring board field.
6498, JP-A-59-230014 (JP-B-61)
-10484). In this method, a coverlay can be easily formed by a process similar to a dry film type permanent mask resist used in the field of conventional printed wiring boards, and it is inexpensive, but flexibility and heat resistance, or Compatibility between flexibility and solvent resistance is not sufficient. Further, it is disclosed in Japanese Patent Application No. 5-117523 that a photosensitive film formed by combining an acrylic resin and a specific urethane monomer is used as a coverlay film, but the solvent resistance and electrical reliability are not sufficient. . Furthermore, all of the acrylic resin type photosensitive films have insufficient flame retardancy.

[0006]

The invention according to claim 1 is excellent in sensitivity and photocurability, can form a pattern efficiently by photolithography, and has folding resistance, solder heat resistance, solvent resistance, and adhesion. Provided is a photosensitive resin composition which has excellent properties and flame retardancy and is excellent in workability in coating on a film. The invention according to claim 2 provides the photosensitive resin composition which exhibits the effect of the invention according to claim 1 and is more excellent in folding resistance and solder heat resistance.

The invention according to claim 3 is excellent in sensitivity and photocurability, can form a pattern efficiently by photolithography, and has folding resistance, solder heat resistance, solvent resistance,
It is intended to provide a photosensitive laminated body which is excellent in adhesion and flame retardancy, and is excellent in handleability and workability for laminating on a substrate. Claim 4
The invention described is excellent in sensitivity and photocurability, can efficiently form a pattern by photolithography, and is excellent in folding resistance, solder heat resistance and flame retardancy, and is also excellent in handleability, and flexible printed board It is intended to provide a photosensitive laminate having excellent manufacturing workability. The invention according to claim 5 is extremely excellent in sensitivity and photocurability, can efficiently form a pattern by photolithography, and is excellent in folding resistance, solder heat resistance, solvent resistance, adhesion and flame retardancy, Further, the present invention provides a photosensitive laminate which is extremely easy to handle and has excellent workability in manufacturing a flexible printed board.

The invention according to claim 6 provides a flexible printed board excellent in folding resistance, solder heat resistance, solvent resistance and flame retardancy, and also excellent in high-density mounting property and electrical reliability. It is intended to provide a method for manufacturing a flexible printed board that can be manufactured with high yield. The invention according to claim 7 provides the method of manufacturing a flexible printed board having the effect of the invention according to claim 6 and having more excellent solder heat resistance.

[0009]

The present invention provides a polyvalent carboxylic acid component (a) containing (A) a polytetramethylene glycol-modified dicarboxylic acid as an essential component and a diisocyanate (b) in an equivalent ratio [(a ) Carboxyl group /
The isocyanate resin of (b)] is reacted with the carboxylic acid-containing polyamide resin (c) obtained under a condition of more than 1, and the epoxy resin (d) is equivalent to the epoxy group / (c) of epoxy group / (c). Of carboxyl group] of 1 or more to the epoxy group-containing polyamide resin (e) obtained by reacting the monocarboxylic acid (f) in an equivalent ratio [(f)
[Carboxyl group / (e) epoxy group] of 1) or more, the epoxy group-capped polyamide resin obtained by the reaction under the condition of 1 or more, (B) photopolymerizable unsaturated having at least one ethylenically unsaturated group at the terminal The present invention relates to a photosensitive resin composition comprising a compound and (C) a photopolymerization initiator that generates a free radical upon irradiation with active light.

In the present invention, 20 to 95 parts by weight of (A) acid anhydride-modified polyamide resin and 5 to 80 parts by weight of (B) photopolymerizable unsaturated compound (provided that component (A) and (The total amount of component (B) is 100 parts by weight) and (C)
0.01 to 20 parts by weight of the photopolymerization initiator (however, (A)
The total amount of the component and the component (B) is 100% by weight), and the photosensitive resin composition.

The present invention also relates to a photosensitive laminate having a layer of the above-mentioned photosensitive resin composition and a support film supporting the layer. The present invention also relates to a photosensitive laminate having a layer of the photosensitive resin composition on the surface of a flexible printed board substrate. The present invention also relates to a photosensitive laminate having a flexible printed board on one surface of the layer of the photosensitive resin composition and a support film on the other surface.

Further, the present invention is characterized in that a pattern of the photosensitive resin composition is formed on the surface of the flexible printed board by imagewise irradiating the photosensitive laminate with active light and developing. A method for manufacturing a flexible printed board. The present invention also relates to the method for manufacturing the flexible printed board, which includes a step of irradiating active light after development and a step of post-heating.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The photosensitive resin composition of the present invention comprises
(A) Polyvalent carboxylic acid component (a) containing polytetramethylene glycol-modified dicarboxylic acid as an essential component
Epoxy resin to carboxylic acid-containing polyamide resin (c) obtained by reacting diisocyanate (b) with an equivalent ratio [carboxyl group of (a) / isocyanate group of (b)] of more than 1 The equivalent ratio of (d) [epoxy group of (d) / carboxyl group of (c)] is 1
The equivalent ratio of the monocarboxylic acid (f) to the epoxy group-containing polyamide-based resin (e) obtained by the reaction under the above conditions is 1 or more [carboxy group of (f) / epoxy group of (e)]. Epoxy group-capped polyamide resin obtained by reacting under the following conditions, (B) a photopolymerizable unsaturated compound having at least one ethylenically unsaturated group at the terminal, and (C) free radicals generated by irradiation with active light. A photopolymerization initiator is an essential component.

In the photosensitive resin composition of the present invention (A)
The polyvalent carboxylic acid component (a), which is a raw material for producing the epoxy group-blocked polyamide resin, which is a component, contains polytetramethylene glycol-modified dicarboxylic acid as an essential component. The amount of the polytetramethylene glycol-modified dicarboxylic acid in the polycarboxylic acid component (a) is 10 to 1
The amount is preferably 00% by weight, more preferably 30 to 90% by weight, and particularly preferably 50 to 80% by weight. If the content is less than 10% by weight, folding resistance as a cover lay for flexible printed boards may not be obtained.

In the polytetramethylene glycol-modified dicarboxylic acid, polytetramethylene glycol and dicarboxylic acid are reacted (dehydrated esterification) under the condition that the equivalent ratio (carboxyl group of dicarboxylic acid / hydroxyl group of polytetramethylene glycol) exceeds 1. It can be synthesized by This equivalent ratio (carboxyl group of dicarboxylic acid / hydroxyl group of polytetramethylene glycol) is 1.1.
It is preferable to be 3 to 3, more preferable to be 1.3 to 2.5, and particularly preferable to be 1.5 to 2. If the equivalent ratio is less than 1, then one having a carboxyl group only at one end (having a hydroxyl group at the other end) or one having no carboxyl group at both ends (having a hydroxyl group at both ends) is produced. If it exceeds 3, the polytetramethylene glycol-modified dicarboxylic acid once generated during the synthesis is likely to undergo acid hydrolysis due to the dicarboxylic acid remaining as an unreacted product, and the heat resistance as a cover lay for a flexible printed board decreases. Tend to do.

The polytetramethylene glycol for synthesizing the polytetramethylene glycol modified dicarboxylic acid is not particularly limited, and for example, Hodogaya Chemical Co., Ltd.
Examples of the product name include PTG series and PTG-SN series manufactured by Co., Ltd. These polytetramethylene glycols may be used alone or in combination of two or more. The molecular weight of polytetramethylene glycol (calculated from the hydroxyl value) is preferably 200 to 5,000, more preferably 500 to 4,000, and 1,000 to 3,000. Is particularly preferable. When the molecular weight is less than 200, folding resistance as a cover lay for flexible printed boards tends to be unobtainable, and when the molecular weight exceeds 5,000, heat resistance tends to be unobtainable.

As the dicarboxylic acid for synthesizing the polytetramethylene glycol-modified dicarboxylic acid,
There is no particular limitation, for example, aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, dodecanedioic acid, eicosanedioic acid, dimer acid, 1,4-cyclohexanedicarboxylic acid, etc. Alicyclic dicarboxylic acids, isophthalic acid, terephthalic acid, phthalic acid, 1,5-naphthalene dicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, and aromatic dicarboxylic acids such as 4,4-diphenyl sulfone dicarboxylic acid. . These dicarboxylic acids are used alone or in combination of two or more.

In the polyvalent carboxylic acid component (a), the other polyvalent carboxylic acid that can be used in combination with the polytetramethylene glycol modified dicarboxylic acid is not particularly limited, and for example, the above polytetramethylene glycol modified dicarboxylic acid is synthesized. Dicarboxylic acid, trimellitic acid anhydride, pyromellitic acid anhydride, benzophenone tetracarboxylic acid dianhydride, s-biphenyltetracarboxylic acid dianhydride, diphenylsulfone tetracarboxylic acid dianhydride,
Examples thereof include methylcyclohexene tetracarboxylic acid dianhydride, polyvalent carboxylic acid anhydrides such as ethylene glycol bisanhydrotrimellitate, polyethylene glycol-modified dicarboxylic acid, polypropylene glycol-modified dicarboxylic acid and the like. These polyvalent carboxylic acids may be used alone or in combination of two or more.

The carboxylic acid-containing polyamide resin (c), which is an intermediate for producing the epoxy group-containing polyamide resin that is the component (A) of the photosensitive resin composition of the present invention, is the polyvalent carboxylic acid component (a). And diisocyanate (b),
It can be obtained by reacting (decarboxylation amidation) under a condition that the equivalent ratio [carboxyl group of (a) / isocyanate group of (b)] exceeds 1. This equivalent ratio [(a) carboxyl group /
The isocyanate group of (b)] is preferably 1.03 to 3, more preferably 1.05 to 1.5, and particularly preferably 1.1 to 1.3. If this equivalent ratio [carboxyl group of (a) / isocyanate group of (b)] is less than 1.03, those having no carboxyl group are likely to be generated and the reaction is difficult to control (the reaction system is isocyanate). On the other hand, when the equivalent ratio exceeds 3, polyvalent carboxylic acid tends to remain as an unreacted product, and the heat resistance of the cover lay for a flexible printed board tends to decrease.

The diisocyanate (b) is not particularly limited and includes, for example, 4,4'-diphenylmethane diisocyanate, 2,6-tolylene diisocyanate, 2,
Aromatic diisocyanates such as 4-tolylene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl ether diisocyanate, m-xylylene diisocyanate, m-tetramethyl xylylene diisocyanate, hexamethylene Aliphatic diisocyanates such as diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and lysine diisocyanate, isophorone diisocyanate, 4,4 '
Alicyclic diisocyanates such as dicyclohexylmethane diisocyanate (hydrogenated 4,4′-diphenylmethane diisocyanate), transcyclohexane-1,4-diisocyanate, hydrogenated m-xylylene diisocyanate, 3,9-bis (3-isocyanate) Propyl) -2,4,8,10-tetraspiro [5,5] undecane and other heterocyclic diisocyanates, and the like.
Of these, aromatic diisocyanates are preferable in terms of heat resistance as a coverlay. These diisocyanates (b) may be used alone, but it is preferable to use two or more kinds in combination in order to improve the solvent solubility of the epoxy group-containing polyamide resin (A).

The reaction (decarboxylation amidation) for obtaining the carboxylic acid-containing polyamide resin (c) from the polycarboxylic acid component (a) and the diisocyanate (b) can be carried out in an organic solvent. The organic solvent is not particularly limited, and examples thereof include lactones such as γ-butyrolactone, ketones such as cyclohexanone, glymes such as diglyme, triglyme and tetraglyme, and N-methyl-2-.
Pyrrolidone, N, N-dimethylacetamide, N, N-
Amides such as dimethylformamide, N, N-dimethylethyleneurea, N, N-dimethylpropyleneurea,
Examples thereof include ureas such as tetramethylurea and sulfones such as sulfolane. Among them, it is preferable to use γ-butyrolactone as a main component in order to reduce the residual solvent in the photosensitive coverlay film manufacturing process.

The epoxy group-containing polyamide resin (e), which is an intermediate for the production of the epoxy group-capped polyamide resin as the component (A) of the photosensitive resin composition of the present invention, is the carboxylic acid-containing polyamide resin ( It is obtained by reacting (hydroxyethyl esterifying) the epoxy resin (d) with respect to c) under the condition that the equivalent ratio [epoxy group of (d) / carboxyl group of (c)] is 1 or more. This equivalent ratio [epoxy group of (d) / carboxyl group of (c)] is
It is preferably 1 to 3, more preferably 1.05 to 1.5, and particularly preferably 1.1 to 1.3. When the equivalent ratio [epoxy group of (d) / carboxyl group of (c)] is less than 1, those having no epoxy group are likely to be formed, while when the equivalent ratio exceeds 3, bridging of the coverlay is carried out. The density tends to be high and the folding endurance tends to be low. In addition, epoxy group-containing polyamide resin (e)
The epoxy equivalent of is preferably 1,000 to 40,000, more preferably 2,000 to 30,000, particularly preferably 3,000 to 20,000, and most preferably 5,000 to 15,000. When the epoxy equivalent is less than 1000, the film forming property tends to decrease, and when it exceeds 40,000, the developability of the photosensitive resin composition tends to decrease.

The epoxy resin (d) used here is not particularly limited, and examples thereof include bisphenol A type epoxy resin, tetrabromobisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, and naphthalene type. Bifunctional aromatic glycidyl ether such as epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene-phenol type epoxy resin, tetraphenylolethane type epoxy resin and other polyfunctional aromatic glycidyl ether, polyethylene glycol Type epoxy resin, polypropylene glycol type epoxy resin, neopentyl glycol type epoxy resin, hexanediol type epoxy resin and other bifunctional aliphatic glycidyl ether, hydrogenated vinyl Bifunctional alicyclic glycidyl ether such as phenol A type epoxy resin, trimethylolpropane type epoxy resin, sorbitol type epoxy resin, polyfunctional aliphatic glycidyl ether such as glycerin type epoxy resin, and difunctional fragrance such as phthalic acid diglycidyl ester Group glycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester and other bifunctional alicyclic glycidyl ester, N, N-diglycidylaniline, N, N-diglycidyltrifluoromethylaniline and other bifunctional Aromatic glycidyl amine,
N, N, N ', N'-tetraglycidyl-4,4-diaminodiphenylmethane, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, o-triglycidyl-p-aminophenol, etc. Polyfunctional aromatic glycidyl amine, alicyclic diepoxy acetal, alicyclic diepoxy adipate, alicyclic diepoxy carboxylate, vinylcyclohexene dioxide and other bifunctional alicyclic epoxy resins, diglycidyl hydantoin and other 2 Examples thereof include functional heterocyclic epoxy resins, polyfunctional heterocyclic epoxy resins such as triglycidyl isocyanurate, and bifunctional or polyfunctional silicon-containing epoxy resins such as organopolysiloxane type epoxy resins. Among these, a bifunctional epoxy resin is preferable in terms of easiness of reaction control, and among the bifunctional epoxy resins, a bifunctional aromatic glycidyl ether is more preferable in terms of improving heat resistance as a coverlay, Among them, the bisphenol A type epoxy resin is particularly preferable in terms of low price, and the tetrabromobisphenol A type epoxy resin is particularly preferable in terms of flame retardancy improvement. These epoxy resins (d) are used alone or in combination of two or more.

The epoxy group-capped polyamide resin as the component (A) in the present invention has an epoxy equivalent of 1000 to
Obtained by reacting 40,000 epoxy group-containing polyamide resin (e) with monocarboxylic acid (f) under the condition that the equivalent ratio [carboxy group of (f) / epoxy group of (e)] is 1 or more. .

In order to obtain the epoxy group-blocked polyamide resin (A), the epoxy equivalent is 1000 to 4000.
It is preferable that the equivalent ratio [carboxyl group of (f) / epoxy group of (e)] of the monocarboxylic acid (f) reacted with the epoxy group-containing polyamide resin (e) of 0 is 1 to 5. It is more preferable that it is 2-3.
2.5 is particularly preferred. If the equivalent ratio is less than 1, unreacted epoxy groups remain, and the storage stability of the photosensitive resin composition tends to decrease. If the equivalent ratio exceeds 5, unreacted monocarboxylic acid (f) Remain in a large amount, and the skin irritation of the polymer varnish tends to increase. The monocarboxylic acid (f) is not particularly limited,
For example, methacrylic acid, ethylenically unsaturated group-containing monocarboxylic acid such as acrylic acid, formic acid, acetic acid, propionic acid,
Examples thereof include saturated aliphatic monocarboxylic acids such as butyric acid and hexanoic acid, and saturated aromatic monocarboxylic acids such as benzoic acid and diphenylacetic acid. Among these, the ethylenically unsaturated group-containing monocarboxylic acid is preferable because it can impart photocurability to the epoxy group-blocked polyamide resin (A). These monocarboxylic acids (f) are used alone or in combination of two or more.

The photopolymerizable unsaturated compound having at least one ethylenically unsaturated group at the terminal used as the component (B) in the photosensitive resin composition of the present invention is not particularly limited, and examples thereof include diethylene glycol dimethacrylate. , Tetraethylene glycol diacrylate, hexapropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, dipentaerythritol pentaacrylate, (Meth) acrylates of polyhydric alcohols such as trimethylolpropane trimethacrylate, 2,2-bis (4-methacryloxyethoxyphenyl) propane, 2,2-bis (4-acryloxyethoxyphenyl) Nil) propane, bisphenol A, epoxy acrylate such as acrylic acid or methacrylic acid adduct of epichlorohydrin type epoxy resin, low molecular weight such as phthalic anhydride-neopentyl glycol-acrylic acid condensate in a 1: 2: 2 molar ratio (Meth) acrylate having benzene ring in the molecule such as unsaturated polyester, adduct of trimethylolpropane triglycidyl ether with acrylic acid or methacrylic acid, acrylic acid monoester of trimethylhexamethylene diisocyanate and dihydric alcohol or methacrylic acid Urethane acrylate compound or urethane methacrylate compound obtained by reaction with monoester, methoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, pheno Shi polyethylene glycol (meth) acrylate, phenoxy polypropylene glycol (meth) acrylate, nonyl phenoxy polyethylene glycol (meth) acrylate,
Nonylphenoxy polypropylene glycol (meth) acrylate and the like can be mentioned, and bisphenol A polyoxyethylene dimethacrylate is preferable from the viewpoint of folding resistance as a coverlay. These compounds may be used alone or in combination of two or more.

The photopolymerization initiator used as the component (C) in the photosensitive resin composition of the present invention is not particularly limited, and examples thereof include benzophenone, 4,4'-bis (dimethylamino) benzophenone (Michler's ketone), 4,
4'-bis (diethylamino) benzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-ethylanthraquinone,
Aromatic ketones such as phenanthrenequinone, benzoin methyl ether, benzoin ethyl ether, benzoin ethyl ether, benzoin ether such as benzoin phenyl ether, benzoin such as methylbenzoin and ethylbenzoin, benzyl derivatives such as benzyldimethylketal, 2- (o-chlorophenyl) -4 , 5-diphenylimidazole dimer,
2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer,
2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl)-
4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5
Examples include 2,4,5-triarylimidazole dimers such as diphenylimidazole dimers, acridine derivatives such as 9-phenylacridine and 1,7-bis (9,9'-acridinyl) heptane. These are used alone or in combination of two or more.

The photosensitive resin composition of the present invention comprises
Component (A), epoxy group-capped amide-based resin 20-95
Parts by weight, 5 to 80 parts by weight of a photopolymerizable unsaturated compound having at least one ethylenically unsaturated group at the end of the component (B), and 0.01 to 20 parts by weight of a photopolymerization initiator of the component (C). . When the compounding amount of the epoxy group-capped amide resin as the component (A) in the photosensitive resin composition is less than 20 parts by weight, the film forming property of the photosensitive element tends to be lowered, and 95 parts by weight is recommended. If it exceeds, the circuit coverage and the solder heat resistance tend to be deteriorated when the photosensitive resin composition is used as a photosensitive element and is thermocompression-bonded to the wiring-formed surface of the flexible printed board to form a coverlay. The blending amount of the component (A) is preferably 30 to 90 parts by weight, more preferably 40 to 90 parts by weight.

Further, at least one ethylenically unsaturated group is added to the terminal of the component (B) in the photosensitive resin composition of the present invention.
If the compounding amount of the photopolymerizable unsaturated compound is less than 5 parts by weight, the sensitivity as a photosensitive resin composition is low, and the cover layer is formed by thermocompression bonding to the surface of the flexible printed board on which the wiring is formed. When it is set to 80% by weight, the circuit coverage tends to decrease, and when it exceeds 80 parts by weight, exudation from the side surface due to the flow of the photosensitive layer in the photosensitive element tends to occur and the storage stability tends to decrease. .
The blending amount of the component (B) is preferably 10 to 70 parts by weight. Further, (C) in the photosensitive resin composition of the present invention
If the amount of the photopolymerization initiator as a component is less than 0.01 parts by weight, it is difficult to obtain sufficient sensitivity, and if it exceeds 20 parts by weight, the light absorption on the exposed surface of the photosensitive resin composition increases to increase the internal content. Light curing tends to be inadequate. The blending amount of the component (C) is preferably 0.05 to 10 parts by weight.

The photosensitive resin composition of the present invention is preferably further used in combination with an amine-based cross-linking agent such as melamine. Preferred amine-based cross-linking agents include, for example, melamine formaldehyde resin, benzoguanamine-formaldehyde resin, urea-formaldehyde resin, glycoluril-formaldehyde resin and the like, and these can be used alone or in combination of two or more kinds. These resins can be made by reacting an acrylamide or methacrylamide copolymer with formaldehyde in an alcohol-containing solution, or by copolymerizing N-alkoxymethyl acrylamide or methacrylamide with another suitable monomer. Particularly suitable amine-based cross-linking agents include American Cyanamid.
melamine manufactured by mid), for example, Cymel (registered trademark)
300, 301, 303, 350, 370, 380, 1
116 and 1130, benzoguanamines such as Cymel® 1123 and 1125, glycoluril resins Cymel® 1170, 1171 and 117
2, as well as the urea-based resin Beetle® 6
0, 65 and 80. Many other similar amine-based crosslinkers are commercially available.

Of the above amine-based cross-linking agents, melamine is more preferred, and melamine formaldehyde resin, ie the reaction product of melamine and formaldehyde, is particularly preferred. These resins are usually ethers such as triacylol melamine and hexaalkylol melamine. The alkyl group preferably has 1 to 8 carbon atoms, and more preferably a methyl group. Depending on the reaction conditions and the formaldehyde concentration, the methyl ethers may react with each other to form more complex units. The amount of the cross-linking agent used is preferably 30% by weight or less based on the total amount of the components (A), (B) and (C).

The photosensitive resin composition of the present invention contains, for example, tetrabromobisphenol A, tetrabromobisphenol A oxyethylene di (meth) acrylate, tetrabromobisphenol A bisallylethyl ester in order to further improve flame retardancy. A flame retardant such as ether or polytetrabromobisphenol A-terminated bromoethoxy compound can be added. Similarly, antimony trioxide,
Flame retardant aids such as antimony pentoxide, barium borate, aluminum hydroxide can also be added. The amount of the flame retardant used is preferably 30% by weight or less based on the total amount of the components (A), (B) and (C). The amount of the flame retardant aid used is preferably 15% by weight or less with respect to the total amount of the components (A), (B) and (C). The photosensitive resin composition of the present invention further includes a dye, a color former,
You may add a plasticizer, a pigment, an adhesion promoter, etc. as needed. The amount of these used is preferably 2% by weight or less based on the total amount of the components (A), (B) and (C).

The photosensitive resin composition of the present invention comprises a solvent capable of dissolving the components (A), (B) and (C), such as toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, soluble in γ-butyrolactone, N-methylpyrrolidone, dimethylformamide, tetramethylsulfone, diethylene glycol dimethyl ether, chloroform, methylene chloride, methyl alcohol, ethyl alcohol, etc.
By mixing, a uniform solution can be obtained. The photosensitive resin composition of the present invention includes screen printing, flow coating, roller coating, slot coating, spin coating, curtain coating, spray coating and dip coating as a liquid coating composition by bringing it into a solution state as described above. It can be coated on a substrate or a support using a general method. At this time, the viscosity of the liquid coating composition can be adjusted by using a solvent, a thickener, a filler and the like as necessary to meet the requirements of each coating method. After coating on the substrate or support, the liquid coating layer is dried to remove the solvent.

The photosensitive resin composition of the present invention can be coated on a support and dried to obtain a photosensitive element (laminate). As the support, a polymer film, for example, a film made of polyethylene terephthalate, polypropylene, polyethylene or the like is used, and among these, a polyethylene terephthalate film is preferable. Since these polymer films must be removable from the photosensitive layer later, they must not have been subjected to a surface treatment or made of a material that cannot be removed. The thickness of these polymer films is usually 5 to 10
0 μm, preferably 10 to 30 μm. One of these polymer films, as a support film of the photosensitive layer,
The other one may be laminated on both sides of the photosensitive layer as a protective film for the photosensitive layer. Further, the photosensitive resin composition of the present invention is coated on a support as described above and dried to form a photosensitive layer,
It is also possible to obtain a laminate by pressing a flexible printed board having wiring formed on the photosensitive layer. Furthermore, the laminate of the present invention can be wound into a roll and stored.

In producing a photoresist image using the photosensitive element of the present invention, when the above-mentioned protective film is present, the protective film is removed, and then the photosensitive layer is pressed against the substrate while heating. By doing so. When manufacturing a flexible printed board, the surface to be laminated is usually a flexible printed board on which wiring is formed by etching or the like, but there is no particular limitation. The thermocompression bonding of the photosensitive layer is usually performed at a temperature of 90 to 130 ° C. and a pressure bonding pressure of 3.0 × 10 ⁵ Pa, but in order to further improve the followability of the photosensitive layer to the flexible printed board,
It is preferable to perform thermocompression bonding under the above conditions under a reduced pressure of 4 × 10 ³ Pa or less. When thermocompression bonding is performed under reduced pressure, it is preferable to use a vacuum laminator having a structure capable of thermocompression bonding the photosensitive layer in a vacuum chamber. Further, if the photosensitive layer is heated as described above, it is not necessary to preheat the substrate in advance, but the substrate can be preheated in order to further improve the followability. In addition, a flexible printed board sheet in which a photosensitive layer is laminated is rolled through a process of continuously feeding out a roll-shaped flexible printed board sheet and continuously laminating the photosensitive layer by thermocompression bonding to the flexible printed board sheet. It can also be wound into a shape. In the step of continuously laminating the photosensitive layers, in order to further improve the followability of the photosensitive layers to the flexible printed board, it is preferable to perform thermocompression bonding under reduced pressure of 4 × 10 ³ Pa or less using a vacuum laminator.

The photosensitive layer thus laminated is
It is then imagewise exposed to actinic light using a negative or positive film. At this time, if the polymer film present on the photosensitive layer is transparent, it may be exposed as it is, but if it is opaque, it must be removed. From the viewpoint of protection of the photosensitive layer, the polymer film is transparent, and it is preferable to expose the polymer film while leaving the polymer film remaining. As the active light, a light generated from a known active light source, for example, a carbon arc, a mercury vapor arc, a xenon arc, or the like is used. The sensitivity of the photoinitiator contained in the photosensitive layer is usually maximum in the UV region, in which case the actinic light source should be one which emits UV radiation effectively. Of course, when the photoinitiator is one that is sensitive to visible light, for example, 9,10-phenanthrenequinone, visible light is used as the active light, and the light source is photographic light other than those mentioned above. Flood bulbs and sun lamps are also used.

The layer of the photosensitive resin composition which has been imagewise exposed to actinic light is usually heated after exposure in order to induce or promote crosslinking of the exposed portion. The heating after the exposure is, for example, heating at a temperature of about 85 to 110 ° C. for about 5 to 60 minutes.

After the exposure, if a polymer film is present on the photosensitive layer, it is removed, and then a suitable developing solution is used, for example, spraying, rocking dipping, brushing,
The unexposed portion is removed by a known method such as scrubbing and development is performed. Examples of the developer include triacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether. , 1,1,1-trichloroethane, N-
Examples include methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, γ-butyrolactone and the like. These can be used alone or in combination of two or more. The temperature can be adjusted according to the developability of the photosensitive layer. A small amount of a surfactant, a defoaming agent or the like may be mixed in this developing solution. These developing solutions contain 1 to 3 for the purpose of preventing ignition.
Water can also be added in the range of 0% by volume.

Further, after development, for the purpose of improving the solder heat resistance, chemical resistance, etc. of the cover lay for the flexible printed board, active light may be irradiated by a high pressure mercury lamp or the like. The irradiation amount of actinic light is generally 0.2 to 10
J / cm ² It is about a degree, and heating at 60 to 180 ° C. may be performed during irradiation. In addition, heating may be performed after development for the same purpose. The heating is preferably performed for 15 to 90 minutes in the range of about 100 to 180 ° C. Both the step of irradiating with active light and the step of heating may be performed, and in this case, both steps may be performed in an arbitrary order.

[0040]

Next, the present invention will be described in more detail by way of examples.

Synthesis Example 1 (Synthesis of polytetramethylene glycol-modified dicarboxylic acid) A flask equipped with a stirrer, a thermometer, a cooling tube, a distillation tube and a nitrogen gas introduction tube was charged with polytetramethylene glycol (Hodogaya Chemical Co., Ltd. ) Product name PTG 1000, average molecular weight 1,000) 1000 parts by weight (1 mole), sebacic acid 405 parts by weight (2 moles) were charged, and condensed water produced as a by-product was toluene in the middle of nitrogen gas ventilation. The temperature was raised to 200 ° C. over 1 hour while azeotropically distilling off. After the mixture was kept at the same temperature for 3 hours to complete the dehydration esterification reaction, it was cooled and then polytetramethylene glycol-modified dicarboxylic acid having an acid value of 82.5 and a molecular weight (calculated from the acid value) of 1,360 (hereinafter, P-1) was obtained.

Synthesis Example 2 (Synthesis of polytetramethylene glycol-modified dicarboxylic acid) As polytetramethylene glycol, Hodogaya Chemical Co., Ltd.
Brand name PTG2000, average molecular weight 2,000
0) was used in an amount of 2000 parts by weight, and 292 parts by weight of adipic acid was used instead of sebacic acid. By the same procedure as in Synthesis Example 1, a polytetramethylene glycol modified with an acid value of 49.6 and a molecular weight of 2,260 was used. Dicarboxylic acid (hereinafter P
-2) was obtained.

Synthesis Example 3 (Synthesis of polytetramethylene glycol-modified dicarboxylic acid) As polytetramethylene glycol, Hodogaya Chemical Co., Ltd.
Brand name PTG2000, average molecular weight 2,000
0) was used in the same manner as in Synthesis Example 1, except that 2000 parts by weight of polytetramethylene glycol-modified dicarboxylic acid having an acid value of 47.0 and a molecular weight of 2,390 (hereinafter referred to as P) was used.
-3).

Synthesis Example 4 (Synthesis of Epoxy Group-Containing Polyamide Resin) Synthesis Example 1 was used as a polyvalent carboxylic acid component (a) in a flask equipped with a stirrer, a thermometer, a cooling pipe and a nitrogen gas introducing pipe.
57.7 parts by weight (42.4 mmol) of the polytetramethylene glycol-modified dicarboxylic acid (P-1) obtained in 1., 4.9 parts by weight of adipic acid (33.6 mmol), 6.8 parts by weight of sebacic acid (33) 0.7 mmol) and isophthalic acid 1
1.2 parts by weight (67.5 mmol) of 177.2 mmol in total, 4,4′-diphenylmethane diisocyanate (hereinafter referred to as MDI) 2 as diisocyanate (b) 2
2.1 parts by weight (88.4 mmol) and tolylene diisocyanate (hereinafter referred to as TDI. 2,6-isomer /
2,4-isomer = 80/20 mol%) 10.3 parts by weight (59.2 mmol) in total 147.6 mmol and 150 parts by weight of γ-butyrolactone as a reaction medium,
The temperature was raised to 200 ° C. while venting the carbon dioxide gas generated as a by-product during the ventilation of nitrogen gas. After keeping the temperature at the same temperature for 3 hours to complete the decarboxylation amidation reaction, the mixture was cooled to 150 ° C., the heating residue (220 ° C./hour) 40% by weight, acid value (resin content conversion) 40.2, 100 parts by weight of a carboxylic acid-containing polyamide resin (hereinafter referred to as c-1) having a molecular weight (calculated from an acid value) of 2,790 (hereinafter, referred to as c-1) (converted into resin content, 35.
8 mmol) was obtained.

Next, it is kept warm at 150 ° C. (c-
In 1), 16.2 parts by weight (43.1 mmol) of Epomic R140P (trade name of Mitsui Petrochemical Industry Co., Ltd.), which is a bisphenol A type epoxy resin, as the epoxy resin (d) and N, N- as the reaction solvent. 66.7 parts by weight of dimethylformamide was added, and the mixture was kept at the same temperature for 3 hours to complete the hydroxyethyl esterification reaction, and then cooled,
Heating residue (220 ° C / 1 hour) 35% by weight, epoxy equivalent (resin equivalent) 8100, hydroxyl equivalent (resin equivalent) 1
An epoxy group-containing polyamide resin (hereinafter, referred to as e-1) having a molecular weight (design value) of 620 and 16,200 was obtained.

By the same operation, the carboxylic acid-containing polyamide resin (shown as c-2, c-3 and c-4) having the composition (converted to resin content) shown in Table 1 and the carboxylic acid for comparison were contained. After obtaining a polyamide-based resin (represented by c-5 and c-6), the epoxy group-containing polyamide-based resin (e-2, e-3 and e-4) having the composition (resin content conversion) and properties shown in Table 2 is obtained. , And a comparative epoxy group-containing polyamide resin (shown by e-5 and e-6). IPDI in Table 1 is isophorone diisocyanate. In addition, Epicoat 1001 in Table 2 is bisphenol A.
Type epoxy resin (made by Yuka Shell Epoxy Co., Ltd.),
Epotote YDB400 is a bisphenol A type brominated epoxy resin (manufactured by Tohto Kasei Co., Ltd.), and is listed in Table 1 and Table 2.
The unit of the compounding amount therein is parts by weight.

[0047]

[Table 1]

[0048]

[Table 2]

Synthesis Example 5 (Synthesis of Epoxy Group-Capped Polyamide Resin) In a flask equipped with a stirrer, a thermometer, a cooling tube and a dry air introducing tube, the epoxy group-containing polyamide resin (e) was used in Synthesis Example 4. 100 parts by weight of (e-1) obtained (equivalent to resin content, 6.17 mmol), 2.1 parts by weight of methacrylic acid (24.4 mmol) as monocarboxylic acid (f), and metoquinone (radical polymerization inhibitor) 0 .21 parts by weight (10% by weight of (f)) and 2.9 parts by weight of N, N-dimethylbenzylamine (catalyst) (1% by weight of solution of (e)) were charged, and 100 ° C. under aeration of dry air. The temperature was raised to.
The temperature is kept at the same temperature for 6 hours to complete the epoxy group blocking reaction, and an epoxy group blocked polyamide resin (hereinafter, A-1) having a hydroxyl equivalent (resin content) of 1360 and a molecular weight (design value) of 16,370 is obtained. It was

By the same operation, the compound shown in Table 3 (converted to resin content), the properties of the epoxy group-capped polyamide resin (shown as A-2, A-3, A-4) and the comparative epoxy were used. A base-blocked polyamide resin (indicated by A-5 and A-6) was obtained. The unit of the compounding amount in Table 3 is parts by weight.

[0051]

[Table 3]

Example 1 The materials shown in Table 4 were blended to prepare a solution of a photosensitive resin composition.

[Table 4]

The solution 6 of the obtained photosensitive resin composition is shown in FIG.
80 to 11 by uniformly coating on a polyethylene terephthalate film 12 having a thickness of 20 μm using the apparatus shown in FIG.
The solvent was removed by drying in a hot air convection dryer 7 at 0 ° C. for about 10 minutes. The thickness of the layer of the photosensitive resin composition after drying was about 50 μm. On the layer of the photosensitive resin composition, a polyethylene film 13 having a thickness of about 25 μm was attached as a protective film as shown in FIG. 1 to obtain a photosensitive laminate (photosensitive element) of the present invention. It was In FIG. 1, 1 is a polyethylene terephthalate film payout roll, 2, 3, 4, 9 and 10 are rolls, 5 is a knife, 8 is a polyethylene film payout roll, and 11 is a photosensitive element take-up roll.

The circuit embedding property and photosensitive property of the obtained photosensitive element, solder heat resistance after resist formation, folding resistance, flame retardancy and storage stability were evaluated by the following methods, and the results are shown in Table 7. Show.

Circuit Embedding Property A substrate for a flexible printed board (made by Nikkan Kogyo Co., Ltd., trade name F
30VC125RC11) copper foil was etched according to a conventional method, and line / space (μm) = 165/165,
Three test patterns of 318/318 and 636/636 A continuous vacuum laminator (made by Hitachi Chemical Co., Ltd., trade name VLM-) on a flexible printed board on which copper circuits are formed.
1 type), the above-mentioned photosensitive element was laminated while peeling the polyethylene film at a heat shoe temperature of 120 ° C., a laminating speed of 0.5 m / s, an atmospheric pressure of 4000 Pa or less, and a pressure bonding pressure of 3.0 × 10 ⁵ Pa.

Subsequently, the appearance of the three test pattern portions is observed with a stereoscopic microscope to check for the presence of bubbles or the like around the copper circuit, and the three test pattern portions are cut out and the copper circuit cross section is observed by an epoxy casting method. Samples were prepared, and the follow-up situation of the coverlay around the copper circuit was examined by an electron microscope to determine the circuit embedding property. The evaluation criteria are as follows. Good: No air bubbles remain and no gap around the copper circuit Poor: Some air bubbles remain or gap around the copper circuit

Photosensitive property A substrate for a flexible printed board in which a copper foil having a thickness of 35 μm is laminated on a polyimide substrate (manufactured by Nikkan Industry Co., Ltd., trade name F
The copper surface of 30VC125RC11) was polished with an abrasive grain brush, washed with water and dried. Continuous vacuum laminator (made by Hitachi Chemical Co., Ltd.) on this flexible printed circuit board
Using the product name VLM-1 type), heat shoe temperature 12
The photosensitive element was laminated while the polyethylene film was peeled off at 0 ° C., a laminating speed of 0.5 m / s, an atmospheric pressure of 4000 Pa or less, and a pressure bonding pressure of 3.0 × 10 ⁵ Pa. Next, Kodak step tablet No. 2 (21-step step tablet manufactured by Eastman Kodak Co., Ltd.) was placed on the polyethylene terephthalate film of the obtained sample.
Were closely contacted with each other, and a predetermined amount of light was exposed using an HMW-201GX type exposure machine manufactured by Oak Manufacturing Co., Ltd. Subsequently, after heating at 100 ° C. for 10 minutes, N-methylpyrrolidone / water = 80
/ 20 (volume ratio) was spray-developed at 40 ° C. for 70 seconds, and the exposure amount required to obtain 8 step tablet stages was taken as the sensitivity.

Photo tool (Kodak Step Tablet No. 2 and line / space (μm) = 30/3
0 to 250/250 (resolution) and line / space (μm) = 30/400 to 250/400 (adhesion) a photo tool having a negative pattern) is adhered onto the polyethylene terephthalate film of the obtained sample. Then, the line / space value of the smallest resolution pattern that gives a rectangular resist formation when exposed and exposed at an exposure amount capable of obtaining 8 step tablet steps is taken as the resolution.

Solder heat resistance In the same manner as described above, a test negative mask was brought into close contact with the sample polyethylene terephthalate film obtained by laminating a photosensitive element on a flexible printed board substrate, and exposure was performed at an exposure amount that would obtain 8 step tablet steps. did. After left at room temperature for 1 hour, the sample polyethylene terephthalate film was peeled off, and N-methylpyrrolidone /
Water = 80/20 (volume ratio) with a developer consisting of 7 at 40 ° C
It was developed by spraying for 0 seconds and dried at 80 ° C. for 10 minutes. Next, using an ultraviolet irradiation device manufactured by Toshiba Denshi Co., Ltd., 3 J /
Irradiation with ultraviolet rays of cm ² was performed, and heat treatment was further performed at 150 ° C. for 40 minutes to obtain a flexible printed board on which a cover lay was formed.

Then, rosin flux MH-820
After applying V (manufactured by Tamura Kaken Co., Ltd.), it was dipped in a solder bath at 260 ° C. for 30 seconds for soldering treatment. After such an operation, the crack generation state of the coverlay and the floating state or peeling state of the coverlay from the substrate were visually evaluated according to the following criteria. Good: No cracks, lifts or peels. Poor: Cracks, lifts or peels.

Solvent resistance A flexible printed board on which a cover lay was formed by the same operation as above was immersed in methyl ethyl ketone and isopropyl alcohol for 10 minutes at room temperature, and then the state of floating and peeling of the cover lay from the substrate was visually observed as follows. It evaluated by the standard of. Good: No floating or peeling Poor: Some floating or peeling

Folding resistance A coverlay was formed on a substrate for a flexible printed board obtained by the same operation as described above, and the sample subjected to the soldering treatment was folded by 180 ° and the coverlay of the folded coverlay was bent. The crack generation status was visually evaluated according to the following criteria. Good: No cracks generated Bad: Cracks generated

Flame Retardancy A flexible printed board having a cover lay obtained by the same operation as described above is UL94 standard (VTM method).
The flame retardancy was evaluated according to.

Storage stability A 90 m long photosensitive element wound in a roll shape was stored at a temperature of 23 ° C. and a humidity of 60%, and the state of the exudation of the photosensitive layer from the side surface of the roll was shown below for 6 months. It was visually evaluated according to the standard. Good: No bleeding of the photosensitive layer even after 6 months. Poor: No bleeding of the photosensitive layer during 6 months.

Examples 2-9 and Comparative Examples 1-6 Epoxy group-capped polyamide resin used in Example 1,
A photosensitive element was produced in the same manner as in Example 1 except that the photopolymerizable unsaturated compound and the additives were changed to those shown in Tables 5 and 6, and processed as a coverlay in the same manner as in Example 1, The evaluation was performed and the results are shown in Tables 7 and 8. Table 5
And in Table 6, TM-A is trimethyl hexamethylene diisocyanate 2 mol, 2-hydroxyethyl methacrylate 2 mol, and cyclohexane dimethanol 1
It is a urethane acrylate compound synthesized from mol and BP is benzophenone, and EAB is 4,4′-bisdiethylaminobenzophenone.

[0066]

[Table 5]

[0067]

[Table 6]

[0068]

[Table 7]

[0069]

[Table 8]

As is clear from Tables 7 and 8, by using the photosensitive resin composition and the photosensitive element of the present invention, both solder heat resistance and folding resistance are good, and flame retardancy is 94V. -1 (UL standard) or 94V-0
It can be seen that a cover lay for flexible printed boards that is (UL standard) is obtained.

[0071]

The photosensitive resin composition according to claim 1 has excellent sensitivity and photocurability, can form a pattern efficiently by photolithography, and has folding resistance, solder heat resistance, solvent resistance, and adhesion. And flame retardancy, and excellent workability for coating on film. The photosensitive resin composition according to claim 2 exhibits the effect of the invention according to claim 1, and has more folding endurance,
Excellent solder heat resistance.

The photosensitive laminate according to claim 3 is excellent in sensitivity and photocurability, can form a pattern efficiently by photolithography, and has folding resistance, solder heat resistance, solvent resistance, adhesion and difficulty. It has excellent flammability, handleability, and workability for stacking on substrates. The photosensitive laminate according to claim 4 is excellent in sensitivity and photocurability, can efficiently form a pattern by photolithography, and is excellent in folding resistance, solder heat resistance and flame retardancy, and is excellent in handleability. Excellent workability in manufacturing flexible printed boards. The photosensitive laminate according to claim 5 is extremely excellent in sensitivity and photocurability, can form a pattern efficiently by photolithography, and has folding resistance, solder heat resistance, solvent resistance, adhesion and flame retardancy. It is also excellent in handleability, and has excellent workability in manufacturing flexible printed boards.

According to the method for producing a flexible printed board according to claim 6, a flexible print excellent in folding resistance, solder heat resistance, solvent resistance and flame retardancy, and also excellent in high-density mounting property and electrical reliability. Plates can be manufactured with good workability and yield. The method for manufacturing a flexible printed board according to claim 7 achieves the effect of the invention according to claim 6, and is more excellent in solder heat resistance.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of a photosensitive element manufacturing apparatus used in Examples and Comparative Examples.

[Explanation of symbols]

1 polyethylene terephthalate film feeding roll 2, 3, 4 roll 5 knife 6 solution of photosensitive resin composition 7 dryer 8 polyethylene film feeding roll 9, 10 roll 11 photosensitive element winding roll 12 polyethylene terephthalate film 13 polyethylene film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 5/00 C08K 5/00 C08L 63/00 NKE C08L 63/00 NKE 77/00 KKU 77/00 KKU C09D 4/00 PDU C09D 4/00 PDU 4/02 PDR 4/02 PDR G03F 7/032 501 G03F 7/032 501 H05K 3/28 H05K 3/28 D // C08F 290/06 C08F 290/06 (72 ) Inventor Hitoshi Amanokura 4-13-1, Higashi-cho, Hitachi-shi, Ibaraki Ibaraki Laboratory, Hitachi Chemical Co., Ltd. (72) Inventor Kenji Suzuki 4-3-1-1, Higashi-cho, Hitachi-shi, Ibaraki Hitachi Chemical Co., Ltd. In Ibaraki Research Center (72) Inventor Hiroshi Nishizawa 4-13-1, Higashimachi, Hitachi City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Ibaraki Research Center

Claims (7)

[Claims] 1. A polyvalent carboxylic acid component (a) comprising (A) a polytetramethylene glycol-modified dicarboxylic acid as an essential component and a diisocyanate (b) in an equivalent ratio [(a) carboxyl group / (b)). Of the carboxylic acid-containing polyamide-based resin (c) obtained by reacting the isocyanate group of [1] with the carboxylic acid-containing polyamide resin (c) in an equivalent ratio [(d) epoxy group / (c) carboxyl group] ] To 1 or more with respect to the epoxy group-containing polyamide resin (e) obtained by the reaction, the monocarboxylic acid (f) is equivalent ratio [(f) carboxyl group /
(Epoxy group of (e)], an epoxy group-capped polyamide resin obtained by the reaction under the condition of 1 or more, (B) a photopolymerizable unsaturated compound having at least one ethylenically unsaturated group at the terminal, and (C ) A photosensitive resin composition comprising a photopolymerization initiator that generates a free radical upon irradiation with active light. 2. The (A) acid anhydride-modified polyamide resin is 20 to 95 parts by weight, and the (B) photopolymerizable unsaturated compound is 5 to 80 parts by weight (provided that the (A) component and the (B) component are used. And (C) the photopolymerization initiator is 0.01 to 20 parts by weight (however, the total amount of the components (A) and (B) is 100 parts by weight). The photosensitive resin composition according to claim 1. 3. A photosensitive laminate having a layer of the photosensitive resin composition according to claim 1 and a support film supporting the layer. 4. A photosensitive laminate having a layer of the photosensitive resin composition according to claim 1 on the surface of a substrate for a flexible printed board. 5. A photosensitive laminate having a flexible printed board on one side of the layer of the photosensitive resin composition according to claim 1 and a support film on the other side. 6. A pattern of a photosensitive resin composition is formed on the surface of a flexible printed board by irradiating the laminate according to claim 4 or 5 imagewise with active light and developing. Flexible printed circuit board manufacturing method. 7. The method for manufacturing a flexible printed board according to claim 6, which includes a step of irradiating with active light after development and a step of post-heating.