JPH09319090A - Photosensitive resin composition, photosensitive laminate and manufacture of flexible printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition superior in sensitivity and photocurability, capable of forming a pattern in high precision by photolithography and superior in folding resistance, solder resistance, flame retardancy, and coating operability on a film, and to provide a photosensitive laminate using this composition. SOLUTION: This photosensitive composition and the photosensitive laminate having a layer of this composition contain (A) an epoxy group-containing polyamide resin obtained by allowing a carboxylic acid-containing polyamide resin (c), obtained by reaction of a polycarboxylic acid component (a) composed essentially of polycarbonatediol-modified dicarboxylic acid and a diisocyanate (b), to react with an epoxy resin (d) in an equivalent ratio (d)/(c) of >=1, and (B) an epoxy resin, and (C) a cationic photopolymerization initiator.

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 polycarbonate diol-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] ] Epoxy group-containing polyamide-based resin obtained by reacting under conditions of 1 or more,
It relates to a photosensitive resin composition comprising (B) an epoxy resin and (C) a cationic photopolymerization initiator.

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) The polycarboxylic acid component (a) containing the polycarbonate diol-modified dicarboxylic acid as an essential component and the diisocyanate (b) have an equivalent ratio [carboxy group of (a) / isocyanate group of (b)] of 1. The epoxy resin (d) is used in an equivalent ratio [(d) with respect to the carboxylic acid-containing polyamide resin (c) obtained by the reaction under the conditions exceeding the above.
The epoxy group-containing polyamide resin, (B) epoxy resin and (C) photocationic polymerization initiator, which are obtained by reacting under the condition that [Epoxy group / (c) carboxyl group] is 1 or more, are essential components.

In the present invention, the polyvalent carboxylic acid component (a), which is a raw material for producing the epoxy group-containing polyamide resin as the component (A), contains a polycarbonate diol-modified dicarboxylic acid as an essential component. The content of the polycarbonate diol-modified dicarboxylic acid in the polycarboxylic acid component (a) is preferably 10 to 100% by weight, more preferably 30 to 90% by weight, and 50
It is particularly preferable that the content be ˜80% by weight. The amount is 10
If the content is less than wt%, the folding resistance as a cover lay for flexible printed boards may not be obtained.

The polycarbonate diol-modified dicarboxylic acid can be synthesized by reacting (dehydrating esterification) the polycarbonate diol and the dicarboxylic acid under the condition that the equivalent ratio (carboxyl group of dicarboxylic acid / hydroxyl group of polycarbonate diol) exceeds 1. it can. This equivalent ratio (carboxyl group of dicarboxylic acid / hydroxyl group of polycarbonate diol) is preferably 1.1 to 3, more preferably 1.3 to 2.5,
It is particularly preferable to set it to 1.5 to 2. This equivalence ratio is 1
If it is less than 3, it is easy to generate a compound having a carboxyl group only at one end (having a hydroxyl group at the other end) or a compound not having a carboxyl group at both ends (having a hydroxyl group at both ends). If it exceeds, the dicarboxylic 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 polycarbonate diol for synthesizing the polycarbonate diol-modified dicarboxylic acid is not particularly limited, and examples thereof include Praxel CD series and Praxel CD-P manufactured by Daicel Chemical Industries Ltd.
L series, Nippon Polyurethane Industry Co., Ltd. product name Niprolan 980, 981 etc. are mentioned. These polycarbonate diols are used alone or in combination of two or more. The molecular weight of the polycarbonate diol (calculated from the hydroxyl value) is 200 to 5,000.
Is more preferable, 500 to 4,000 is more preferable, 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.

The dicarboxylic acid for synthesizing the polycarbonate diol-modified dicarboxylic acid is not particularly limited, and examples thereof include succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, dodecanedioic acid and eicosane. Aliphatic dicarboxylic acids such as diacids, dimer acids, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, isophthalic acid, terephthalic acid, phthalic acid, 1,5-naphthalenedicarboxylic acid, 4,4-diphenyletherdicarboxylic acid Examples thereof include acids and aromatic dicarboxylic acids such as 4,4-diphenylsulfone 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 which can be used in combination with the polycarbonate diol-modified dicarboxylic acid is not particularly limited, and for example,
Dicarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, s-biphenyltetracarboxylic dianhydride, diphenylsulfonetetracarboxylic dianhydride for synthesizing the above polycarbonate diol-modified dicarboxylic acid Anhydrides, methylcyclohexene tetracarboxylic dianhydride, polyvalent carboxylic acid anhydrides such as ethylene glycol bisanhydrotrimellitate, polyethylene glycol modified dicarboxylic acid,
Examples thereof include polypropylene glycol-modified dicarboxylic acid and polytetramethylene glycol-modified dicarboxylic acid. These other 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 which is the component (A) of the photosensitive resin composition of the present invention has an equivalent ratio of the epoxy resin (d) to the carboxylic acid-containing polyamide resin (c) [( It can be obtained by reaction (hydroxyethyl esterification) under the condition that the ratio of (d) epoxy group / (c) carboxyl group] is 1 or more. The equivalent ratio [epoxy group of (d) / carboxyl group of (c)] is preferably 1 to 3, more preferably 1.05 to 1.5, and 1.1 to 1.3. Is particularly preferable.
When the equivalent ratio [epoxy group of (d) / carboxyl group of (c)] is less than 1, epoxy compounds having no epoxy group are easily generated, while when the equivalent ratio exceeds 3, excess epoxy remains. The resin tends to increase the bridging density of the coverlay and reduce the folding endurance. The epoxy equivalent of the epoxy group-containing polyamide resin that is the component (A) is preferably 1000 to 40000, and 30
More preferably, it is from 00 to 20000, and it is 5000.
It is particularly preferable to set it to ˜15000. If the epoxy equivalent is less than 1000, the film-forming property tends to decrease, and if 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 resin used as the component (B) in the photosensitive resin composition of the present invention is not particularly limited, and those listed as the above-mentioned epoxy resin (d) can be mentioned. A bifunctional epoxy resin is preferable in terms of ease of use, and among the bifunctional epoxy resins, a bifunctional aromatic glycidyl ether is more preferable from the viewpoint of improving heat resistance as a coverlay, and among them, in terms of low price, etc. A bisphenol A type epoxy resin is particularly preferable, and a tetrabromobisphenol A type epoxy resin is particularly preferable from the viewpoint of improving flame retardancy. The epoxy resin as the component (B) is used alone or in combination of two or more kinds, and may be the same as or different from the epoxy resin (d). The blending amount of the epoxy resin as the component (B) is preferably 5 to 50 parts by weight, and 10 to 3 parts by weight based on 100 parts by weight of the epoxy group-containing polyamide resin as the component (A).
More preferably, it is 0 parts by weight. If the amount is less than 5 parts by weight, the sensitivity, resolution, solder heat resistance and solvent resistance tend to decrease, and if it exceeds 50 parts by weight, the resolution, folding endurance and storage stability tend to decrease. is there.

Examples of the photocationic polymerization initiator used as the component (C) in the photosensitive resin composition of the present invention include aryl diazonium salts, diaryliodonium salts, triaryl sulfonium salts, triaryl selenonium salts and dialkylphenas. Examples thereof include dilsulfonium salt, dialkyl-4-hydroxyphenylsulfonium salt and sulfonic acid ester.

The aryldiazonium salt has the general formula (I)

Embedded image [In the formula, Ar ¹ is an alkyl group, a nitro group, an alkoxy group,
A ( ¹ ) to ( ³ ) substituted or unsubstituted phenyl group having one or more kinds of substituents selected from a morpholino group and chlorine, and (X ¹ ) ^- Is (PF ₆ ) ^- , (As
F ₆ ) ^- , (SbF ₆ ) ^- , (SbCl ₆ ) ^- , (BF ₄ ) ^- Or (Fe
Cl ₄ ) ^- The Lewis acid is generated by light irradiation. Specific examples of the aryldiazonium salt include 4-morpholino-2,5-dibutyroxybenzenediazonium borofluoride salt, phenyldiazonium hexafluorophosphonium salt, phenyldiazonium borofluoride salt, phenyldiazonium hexafluoroantimonate salt, and the like. Is mentioned.

The diaryliodonium salt has the general formula (I
I)

Embedded image[In the formula, Ar^TwoIs an alkyl group, a nitro group, an alkoxy group,
One selected from a morpholino group and chlorine, or
A 1-3-substituted phenyl group having two or more substituents, or
An unsubstituted phenyl group, (X^Two)^- Is (PF₆)^- , (As
F₆)^- , (BF_Four)^- , (ClO_Four)^- , (CF_ThreeSO_Three)^- , (F
SO_Three)^- Or (F_TwoPO_Two)^- Is a compound represented by
is there. As a specific compound of diaryliodonium salt
For example, diphenyliodonium hexafluorophore
Sphonium salt, diphenyliodonium hexafluoroa
Examples include ntimonate salt.

The triarylsulfonium salt has the general formula (III)

[Chemical 3][In the formula, Ar^ThreeIs an alkyl group, a nitro group, an alkoxy group,
One selected from a morpholino group and chlorine, or
A 1-3-substituted phenyl group having two or more substituents, or
An unsubstituted phenyl group, (X^Three)^- Is (PF₆)^- , (As
F₆)^- , (BF_Four)^- , (ClO_Four)^- , (CF_ThreeSO_Three)^- , (F
SO_Three)^- Or (F_TwoPO_Two)^- Is a compound represented by
is there. Specific compound of triarylsulfonium salt
For example, triphenylsulfonium hexafluoro
Rophosphonium salt, triphenylsulfonium hexaf
Loroantimonate salt, diphenyl-4-thiophenoki
Cyphenylsulfonium hexafluoroantimonate
Salt, diphenyl-4-thiophenoxyphenylsulfoni
Umhexafluoroantimonate salt, diphenyl-4-
Thiophenoxyphenyl sulfonium pentafluorohydride
Roxyantimonate salt etc. are mentioned.

The triarylselenonium salt has the general formula (IV)

Embedded image[In the formula, Ar^FourIs an alkyl group, a nitro group, an alkoxy group,
One selected from a morpholino group and chlorine, or
A 1-3-substituted phenyl group having two or more substituents, or
An unsubstituted phenyl group, (X^Four)^- Is (PF₆)^- , (As
F₆)^- , (BF_Four)^- , (ClO_Four)^- , (CF_ThreeSO_Three)^- , (F
SO_Three)^- Or (F_TwoPO_Two)^- Is a compound represented by
is there. Specific compounds of triarylselenonium salts and
For example, triphenylselenonium hexafluoro
Rophosphonium salt, triphenylselenonium borofluoride
Salt, triphenylselenonium hexafluoroantimo
Nate salts and the like.

The phenacylsulfonium salt has the general formula (V)

Embedded image [In the formula, Ar ⁵ is an alkyl group, a nitro group, an alkoxy group,
A 1 to 3 substituted phenyl group having 1 or 2 or more substituents selected from morpholino groups and chlorine or an unsubstituted phenyl group, R ¹ and R ² are alkyl groups or benzyl groups, (X ⁵ ) ^- Is (AsF ₆ ) ^- , (SbF ₆ ) ^-
Or (PF ₆ ) ^- It is. ] The compound shown by these. The phenacyl phosphonium salt, for example, dimethyl phenacyl sulfonium hexafluoroantimonate salt,
Examples thereof include diethylphenacylsulfonium hexafluoroantimonate salt.

The 4-hydroxyphenylsulfonium salt has the general formula (VI)

[Chemical 6] [In the formula, Ar ⁶ is an alkyl group, a nitro group, an alkoxy group,
A 1 to 3 substituted phenyl group or an unsubstituted phenyl group having 1 or 2 or more substituents selected from morpholino groups and chlorine, R ³ and R ⁴ are alkyl groups or benzyl groups, (X ⁶ ) ^- Is (AsF ₆ ) ^- , (SbF ₆ ) ^-
Or (PF ₆ ) ^- It is. ] The compound shown by these. Four
Examples of the -hydroxyphenylsulfonium salt include 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate salt, 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate salt and the like.

As the sulfonic acid ester, α-hydroxymethylbenzoin sulfonic acid ester represented by the following general formula (VII), N-hydroxyimide sulfonate represented by the following general formula (VIII), and the following general formula (I
Examples include α-sulfonyloxyketone represented by X) and β-sulfonyloxyketone represented by the following general formula (X).

[0033]

[Chemical 7] [In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² ,
R ¹³ , R ¹⁴ and R ¹⁵ each independently represent an alkyl group or an aryl group. ]

The amount of the photocationic polymerization initiator as the component (C) used depends on the photosensitivity and the heat resistance of the resulting coating film (A).
It is preferable to set 0.01 to 30 parts by weight to 100 parts by weight of the epoxy group-containing polyamide resin as a component,
More preferably, the amount is 0.05 to 10 parts by weight. If the amount used is less than 0.01 parts by weight, sufficient sensitivity cannot be obtained, and if it exceeds 30 parts by weight, the heat resistance of the obtained coating film decreases. By using a photosensitizer together with the photocationic polymerization initiator (C) used in the present invention, the photocurability of the photosensitive resin composition can be further promoted. Examples of the photosensitizer include erythrosine, eosin, perylene, anthracene, phenothiazine, pyrene, coronene, 1,2-benzanthracene, benzophenone, thioxanthone, 2-chlorothioxanthone, 9-fluorenone, and anthraquinone. The amount of the photosensitizer used is preferably 2% by weight or less based on the cationic photopolymerization initiator.

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, Gamma-butyrolactone, N-methyl-2-pyrrolidone, N, N-dimethylformamide, tetramethylsulfone, diethylene glycol dimethyl ether, chloroform, methylene chloride, methyl alcohol, ethyl alcohol, etc. are dissolved and mixed to form a uniform solution. be able to. 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 4000 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 stacking the photosensitive layers, in order to further improve the followability of the photosensitive layers to the flexible printed board, it is preferable to use a vacuum laminator and perform thermocompression bonding under a reduced pressure of 4000 Pa or less.

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 accelerate the 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, using a suitable developing solution, 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-
Methyl-2-pyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, γ-
Examples include butyrolactone. 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. Water may be added to these developers in the range of 1 to 30% by volume for the purpose of preventing ignition.

Further, after the 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
It is about J / cm ² , and heating at 60 to 180 ° C. may be performed during irradiation. In addition, heating may be performed after development for the same purpose. Heating is 15 within the range of 100 to 180 ° C.
It is preferably carried out for 90 minutes. You may perform both the process of irradiating these active lights and the process of heating, in that case,
Both steps can be performed in any order.

[0045]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention.

Synthesis Example 1 (Synthesis of Polycarbonate Diol-Modified Dicarboxylic Acid) A flask equipped with a stirrer, a thermometer, a cooling pipe, a distilling pipe, and a nitrogen gas introducing pipe was charged with polycarbonate diol (trade name of Daicel Chemical Industries, Ltd.). 1000 parts by weight (1 mol) of Praxel CD210 and 1,000 parts by weight of average molecular weight and 405 parts by weight (2 mol) of sebacic acid were charged, and the condensed water produced as a by-product was azeotropically distilled with toluene under nitrogen gas ventilation. Then, the temperature was raised to 200 ° C. over 1 hour. After keeping the temperature at the same temperature for 3 hours to complete the dehydration esterification reaction, the mixture was cooled and then cooled with a polycarbonate diol-modified dicarboxylic acid having an acid value of 82.5 and a molecular weight (calculated from the acid value) of 1,360 (hereinafter referred to as P- 1).

Synthesis Example 2 (Synthesis of Polycarbonate Diol-Modified Dicarboxylic Acid) As a polycarbonate diol, Daicel Chemical Industries Ltd.
Brand name Praxel CD220 manufactured by K.K., average molecular weight 2,
2000 parts by weight and 292 parts by weight of adipic acid instead of sebacic acid were used, and a polycarbonate diol-modified dicarboxylic acid having an acid value of 49.6 and a molecular weight of 2,260 was obtained by the same operation as in Synthesis Example 1. (Hereafter, P
-2) was obtained.

Synthesis Example 3 (Synthesis of Polycarbonate Diol-Modified Dicarboxylic Acid) As a polycarbonate diol, Daicel Chemical Industries Ltd.
Brand name Praxel CD220 manufactured by K.K., average molecular weight 2,
2,000) and a polycarbonate diol-modified dicarboxylic acid having an acid value of 47.0 and a molecular weight of 2,390 (hereinafter, referred to as P
-3).

Synthesis Example 4 (Synthesis of Epoxy Group-Containing Polyamide Resin) Synthesis Example 1 was used as a polycarboxylic acid component (a) in a flask equipped with a stirrer, a thermometer, a cooling pipe and a nitrogen gas introducing pipe.
Polycarbonate diol modified dicarboxylic acid (P
-1) 57.7 parts by weight (42.4 mmol), adipic acid 4.9 parts by weight (33.6 mmol), sebacic acid 6.
8 parts by weight (33.7 mmol) and isophthalic acid 11.
27.2 parts by weight (67.5 mmol), 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. 2,4-isomer /
2,6-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 solvent were charged,
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 A-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 (indicated by c-5 and c-6), the epoxy group-containing polyamide-based resin (A-2, A-3 and A-4) having the composition (converted to a resin content) and properties shown in Table 2 is obtained. And a comparative epoxy group-containing polyamide resin (shown by A-5 and A-6). In addition, IPDI in Table 1 is isophorone diisocyanate, and Table 2
Epicoat 1001 therein is a bisphenol A type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.), and the unit of the blending amount in Tables 1 and 2 is parts by weight.

[0052]

[Table 1]

[0053]

[Table 2]

Example 1 The materials shown in Table 3 were blended to prepare a solution of a photosensitive resin composition.

[Table 3]

The solution of the obtained photosensitive resin composition was added to 180
Using a screen printing machine using a mesh stainless screen plate, a flexible printed board substrate in which a copper foil having a thickness of 35 μm is laminated on a polyimide substrate (Nikan Kogyo Co., Ltd.)
(Trade name: F30VC125RC11) manufactured by Japan, and etched according to a conventional method to obtain a line / space (μm) = 16.
5/165, 318/318, 636/636 test patterns were printed on the entire surface of a flexible printed board on which a copper circuit was formed so that the film thickness after drying was about 40 μm, and then at about 100 ° C. for 30 minutes. A sample was prepared by predrying for 1 minute. Using this sample, characteristics were evaluated by the following methods, and the results are shown in Table 4.

Photosensitivity Kodak step tablet No. 2 (21-step step tablet manufactured by Eastman Kodak Co., Ltd.) was brought into close contact with the sample, and a HMW-201GX type exposure machine manufactured by Oak Manufacturing Co., Ltd. was used. It was quantitatively exposed and subsequently heated at 100 ° C. for 10 minutes. Then, 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. Also, photo tools (Kodak Step Tablet No. 2 and line / space (μm) = 30/30 to 250/250 (resolution), and line / space (μm) = 30/400 to 250 /
When a photo tool having a negative pattern of 400 (adhesiveness) is adhered from the polyethylene terephthalate film of the obtained sample and exposed and developed with an exposure amount necessary to obtain 8 step tablet steps, a rectangle is formed. The value of the line / space of the smallest resolution pattern that can obtain the resist shape is defined as the resolution.

Solder heat resistance A test negative mask was brought into close contact with the sample and exposed so that a step tablet number of 8 could be obtained.
Heated at 0 ° C for 10 minutes. Then, spray development was performed at 40 ° C. for 70 seconds with a developing solution composed of N-methylpyrrolidone / water = 80/20 (volume ratio), and dried at 80 ° C. for 10 minutes.
Next, a Toshiba ultraviolet ray irradiation device (Toshiba Denshi Co., Ltd.) was used to irradiate with 3 J / cm ² of ultraviolet ray, and heat treatment was further performed at 150 ° C. for 40 minutes to obtain a flexible printed board on which a resist pattern was formed. Then, after applying rosin flux MH-820V (manufactured by Tamura Kaken Co., Ltd.), 2
A soldering treatment was performed by immersing the solder in a solder bath at 60 ° C. for 30 seconds. After such an operation, the state of cracking of the resist and the state of floating or peeling of the resist 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 having a resist pattern obtained by the same operation as above was immersed in methyl ethyl ketone and isopropyl alcohol at room temperature for 10 minutes, and then,
The state of floating and peeling of the resist from the substrate was visually evaluated according to the following criteria. Good: No floating or peeling Poor: Some floating or peeling

Folding resistance A rosin-based flux MH-8 was applied to a flexible printed board having a resist pattern formed by the same operation as above.
After applying 20 V (manufactured by Tamura Kaken Co., Ltd.), it was dipped in a solder bath at 260 ° C. for 30 seconds for soldering treatment. The sample was bent by 180 ° by twist folding, and the occurrence of cracks in the resist when bent was visually evaluated according to the following criteria. Good: No cracks generated Bad: Cracks generated

Flame Retardancy A flexible printed board on which a resist pattern obtained by the same operation as described above is formed is UL94 standard (VT
Flame retardancy was evaluated according to the M method).

Examples 2 to 4 and Comparative Examples 1 to 2 A solution of a photosensitive resin composition having the composition shown in Table 4 (other components are the same as in Example 1) was prepared and the same operation as in Example 1 was performed. A flexible printed board on which a resist pattern was formed was prepared and evaluated in the same manner as in Example 1, and the results are shown in Table 4. The unit of the compounding amount in Table 4 is parts by weight,
B-1 is Epomic R140, B-2 is Epicoat 10
C-1 means triphenylsulfonium hexafluoroantimonate salt, and C-2 means diphenyliodonium hexafluorophosphonium salt.

[0062]

[Table 4]

Example 5 A solution of a photosensitive resin composition containing the components shown in Table 5 was prepared.

[Table 5]

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 6. Show. The unit of the compounding amount in Table 6 is parts by weight.

Circuit embedding property A substrate for a flexible printed board (made by Nikkan Industry Co., Ltd., trade name F, in which a copper foil having a thickness of 35 μm is laminated on a polyimide base material
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 (copper name F, manufactured by Nikkan Industry Co., Ltd.) in which a copper foil having a thickness of 35 μm is laminated on a polyimide base material.
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. Then, after heating at 100 ° C. for 10 minutes, a developing solution composed of N-methyl-2-pyrrolidone / water = 80/20 (volume ratio) was used at 70 ° C. at 70 ° C.
The sensitivity was defined as the exposure amount necessary to obtain 8 step tablet stages by carrying out spray development for 2 seconds.

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 shape when exposed and developed with an exposure amount that can obtain the number of steps of 8 step tablets was taken as the resolution.

Solder heat resistance In the same manner as described above, a negative mask for testing was brought into close contact with the sample polyethylene terephthalate film in which a photosensitive element was laminated on a substrate for flexible printed board, and exposure was performed with an exposure amount that could obtain 8 step tablet steps. did. Subsequently, after heating at 100 ° C. for 10 minutes, the sample polyethylene terephthalate film was peeled off, and spray development was performed at 40 ° C. for 70 seconds with a developing solution consisting of N-methylpyrrolidone / water = 80/20 (volume ratio), and then 80 ° C. And dried for 10 minutes. Then, using an ultraviolet irradiation device manufactured by Toshiba Densa Co., Ltd., ultraviolet irradiation of 3 J / cm ² was performed, and further 150
A heat treatment was performed at 40 ° 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 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 flexible printed board obtained by the same operation as above, and the sample subjected to the soldering treatment was folded by 180 °, and the 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 6 to 8 and Comparative Examples 3 to 4 The procedure of Example 5 was repeated except that the epoxy group-containing polyamide resin and epoxy resin used in Example 5 were replaced by those shown in Table 6. A flexible printed board on which a resist pattern was formed was produced, various properties were evaluated in the same manner as in Example 5, and the results are shown in Table 6. In addition, in Table 6,
The unit of the compounding amount is parts by weight.

[0077]

[Table 6]

As is clear from Tables 4 and 6, by using the photosensitive resin composition and the photosensitive element of the present invention, both the solder heat resistance and the folding resistance are good, and the 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.

[0079]

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 manufacturing 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 C08L 77/00 LQT C08L 77/00 LQT G03F 7/004 512 G03F 7/004 512 7/029 7 / 029 7/032 501 7/032 501 7/40 501 7/40 501 H05K 1/03 670 H05K 1/03 670A 3/28 3/28 D (72) Inventor Hitoshi Amanokura 4-13, Higashimachi, Hitachi City, Ibaraki Prefecture No. 1 Hitachi Chemical Co., Ltd. in Ibaraki Research Center (72) Inventor Kenji Suzuki 4-13-1, Higashimachi, Hitachi City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. in Ibaraki Research Center (72) Inventor Hiroshi Nishizawa Hitachi City, Ibaraki Prefecture 4-13-1, Higashimachi Hitachi Chemical Co., Ltd. Ibaraki Research Center

Claims (7)

[Claims] 1. A polyvalent carboxylic acid component (a) comprising (A) a polycarbonate diol-modified dicarboxylic acid as an essential component and a diisocyanate (b) in an equivalent ratio [(a) carboxyl group / (b) isocyanate). Group] is more than 1, the epoxy resin (d) is used in an equivalent ratio [epoxy group of (d) / carboxyl group of (c)] with respect to the carboxylic acid-containing polyamide resin (c) obtained. A photosensitive resin composition comprising an epoxy group-containing polyamide resin obtained by reacting under conditions of 1 or more, (B) an epoxy resin, and (C) a cationic photopolymerization initiator. 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.