JPH09319086A - 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 comprise (A) an acid-anhydride-modofied polyamide resin obtained by allowing an epoxy resin and a monocarboxylic acid to react with the reaction product of apolycarboxic acid containing a polycarbonatediol-modified dicarboxylic acid and a diisocyanate, and allowing the obtained epoxy-blocked type polyamide to react with a cyclic polycarboxylic acid monoanhydride and an unsaturated isocyanate monomer, (B) a photopolymerizable unsaturated compound having at least one ethylenically unsaturated group on the terminal, and (C) a photopolymerazation 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 resin (e) obtained by reacting under the condition that
And / or an equivalent ratio of the monocarboxylic acid (f) to (e) [(f) carboxyl group / (e) epoxy group]
Of the cyclic polyvalent carboxylic acid monoanhydride (h) with respect to the epoxy group-capped polyamide resin (g) obtained by the reaction under the condition that the ratio is 1 or more.
(E) and / or (g) hydroxyl group] is in the range of 0.1 to 2, and the isocyanate monomer (i) having an ethylenically unsaturated group is used in an equivalent ratio [(i) of isocyanate group / (e) and / Or (hydroxyl group of (g)] is an acid anhydride-modified polyamide resin obtained by reacting under a condition of 2 or less,
(B) a photopolymerizable unsaturated compound having at least one ethylenically unsaturated group at the terminal, and (C) a photopolymerization initiator capable of generating a free radical upon irradiation with active light. Resin composition.

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 a photosensitive resin composition is formed on the surface of a flexible printed board by imagewise irradiating the photosensitive laminate with active light and developing the flexible printed board. Manufacturing method. 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.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the photosensitive resin composition of the present invention comprises a polyvalent carboxylic acid component (a) and a diisocyanate (b) containing (A) a polycarbonate diol-modified dicarboxylic acid as an essential component. And the equivalent ratio [(a)
Of carboxyl group / (isocyanate group of (b)] is more than 1, the epoxy resin (d) is equivalent to the carboxylic acid-containing polyamide resin (c) obtained by the reaction [(d) epoxy group / (C) carboxyl group] is 1 or more, and the equivalent ratio of the monocarboxylic acid (f) to the epoxy group-containing polyamide resin (e) and / or (e) obtained by the reaction [(f ) Carboxyl group /
[Epoxy group of (e)] is equivalent to 1 or more, and the cyclic polyvalent carboxylic acid monoanhydride (h) is equivalent to the epoxy group-capped polyamide resin (g) obtained by the reaction [(h) Acid anhydride group / (e) and / or (g) hydroxyl group] in the range of 0.1 to 2 and an isocyanate monomer (i) having an ethylenically unsaturated group in an equivalent ratio [(i) isocyanate Group / (e) and / or (g) hydroxyl group] is 2 or less in the range of the acid anhydride-modified polyamide resin obtained by the reaction, (B) at least one ethylenically unsaturated group at the end Photopolymerizable unsaturated compound having (C)
A photopolymerization initiator that generates a free radical upon irradiation with active light 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 acid anhydride-modified polyamide resin as the component, 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 to 80% by weight. Is particularly preferred.
If the content is less than 10% by weight, 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. When this equivalent ratio is less than 1.1, one having a carboxyl group only at one end (having a hydroxyl group at the other end) or one having neither carboxyl group (having a hydroxyl group at both ends) Is more likely to be produced, and if it exceeds 3, the polycarbonate diol-modified dicarboxylic acid once produced 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 is deteriorated. Tend to do.

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. If the molecular weight is less than 200, the folding resistance as a cover lay for flexible printed boards becomes insufficient, and if 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), other polyvalent carboxylic acids that can be used in combination with the polycarbonate diol-modified dicarboxylic acid are not particularly limited, and examples thereof include:
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-based resin (c), which is an intermediate for producing the acid anhydride-modified polyamide-based resin which is the component (A) of the photosensitive resin composition of the present invention, is the polyvalent carboxylic acid component (a). ) And diisocyanate (b) are reacted (decarboxylation amidation) under the condition that the equivalent ratio [carboxyl group of (a) / isocyanate group of (b)] exceeds 1. Equivalent ratio [(a) carboxyl group / (b)
[Isocyanate group of 1] is less than 1, it is easy to generate a product having no carboxyl group, and it is difficult to control the reaction (the reaction system easily gels due to a side reaction of the isocyanate group), while the equivalent ratio is 3 If it exceeds, the polycarboxylic acid is likely to remain as an unreacted product, and the heat resistance of the cover lay for a flexible printed board tends to be lowered. This equivalent ratio [(a) carboxyl group / (b) isocyanate group] is preferably 1.03 to 3, more preferably 1.05 to 1.5.
It is particularly preferable to set it to 1 to 1.3.

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 acid anhydride-modified polyamide resin (A).

A carboxylic acid-containing polyamide resin (c) comprising a polycarboxylic acid component (a) and a diisocyanate (b).
The reaction for obtaining (decarboxylation amidation) can be carried out in an organic solvent. The organic solvent is not particularly limited,
For example, lactones such as γ-butyrolactone, ketones such as cyclohexanone, glymes such as diglyme, triglyme and tetraglyme, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and the like. Examples thereof include amides, ureas such as N, N-dimethylethyleneurea, N, N-dimethylpropyleneurea and tetramethylurea, and sulfones such as sulfolane. Among them, γ-butyrolactone is the main component. It is preferable in terms of reduction of residual solvent in the photosensitive coverlay film manufacturing process.

The epoxy group-containing polyamide resin (e), which is an intermediate for producing the acid anhydride-modified 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. 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, 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.
The epoxy equivalent of the epoxy group-containing polyamide resin (e) is preferably 1000 to 40000, more preferably 3000 to 20000,
It is particularly preferably set to 5000 to 15000. 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 acid anhydride-modified polyamide resin as the component (A) in the present invention has an equivalent ratio of the monocarboxylic acid (f) to the epoxy group-containing polyamide resin (e) and / or (e) [( The carboxyl group of (f) / the epoxy group of (e)] is reacted with the epoxy group-capped polyamide resin (g) obtained under the condition of 1 or more, and the cyclic polyvalent carboxylic acid monoanhydride (h) is added thereto. The equivalent ratio [an acid anhydride group of (h) / (e) and / or a hydroxyl group of (g)] is 0.1.
In the range of 2, the isocyanate monomer (i) having an ethylenically unsaturated group is used in an equivalent ratio [isocyanate group / (i) /
The hydroxyl group of (e) and / or (g)] can be obtained by reacting under the condition of 2 or less.

To obtain the epoxy group-capped polyamide resin (g), the epoxy group-containing polyamide resin (e) is reacted with an equivalent ratio of monocarboxylic acid (f) [(f) carboxyl group / (e). ) Epoxy group] is 1
It is preferable that it is -5, it is more preferable that it is 1.2-3, and it is particularly preferable that it is 1.5-2.5. 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, and examples thereof include an ethylenically unsaturated group-containing monocarboxylic acid such as methacrylic acid and acrylic acid, formic acid,
Examples thereof include saturated aliphatic monocarboxylic acids such as acetic acid, propionic acid, 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 in that the photocurability of the acid anhydride-modified polyamide resin (A) can be improved. These monocarboxylic acids (f)
Are used alone or in combination of two or more.

The equivalent ratio [(h) of acid anhydride groups / (of cyclic polycarboxylic acid anhydride (h) and epoxy group-containing polyamide resin (e) and / or epoxy group-capped polyamide resin (g)] e) and / or (g) hydroxyl group] is 0.1
2 and preferably 0.2 to 1, and 0.3
It is more preferably set to 0.9, and particularly preferably set to 0.5 to 0.8. If this equivalent ratio is less than 0.1, the developability of the photosensitive resin composition tends to decrease, and if it exceeds 2, a large amount of the cyclic polycarboxylic acid monoanhydride (h) is present as an unreacted product. And the storage stability of the acid anhydride-modified polyamide resin (A) tends to decrease.

The cyclic polycarboxylic acid monoanhydride (h) is not particularly limited, and examples thereof include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride and hexahydrophthalic anhydride. , Methyl hexahydrophthalic anhydride, nadic acid anhydride, methyl nadic acid anhydride, methyl 2-substituted butenyl tetrahydrophthalic anhydride, itaconic acid anhydride, succinic acid anhydride, citraconic acid anhydride, alkenylic acid anhydride , Dodecenyl succinic anhydride, tricarballylic anhydride, maleic anhydride, linoleic acid adduct of maleic anhydride, maleic anhydride adduct of methylcyclopentadiene, alkylated endoalkylene tetrahydrophthalic anhydride, phthal Acid anhydride, trimellitic anhydride, chlorend Anhydride, tetrachlorophthalic anhydride, include such tetrabromophthalic anhydride, among others, reactivity, reaction yield, in terms of low cost, etc., tetrahydrophthalic acid anhydride is preferred. These cyclic polycarboxylic acid monoanhydrides (h) are used alone or in combination of two or more.

Equivalent ratio [(i) of isocyanate group (i) having ethylenically unsaturated group and epoxy group-containing polyamide resin (e) and / or epoxy group-capped polyamide resin (g)] / (E) and / or (g) hydroxyl group] is 2 or less, 0.05
It is preferable to be set to 0.9, more preferably set to 0.1 to 0.6, and particularly preferably set to 0.15 to 0.35. When this equivalent ratio exceeds 2, a large amount of the isocyanate monomer (i) having an ethylenically unsaturated group remains as an unreacted product, and the storage stability of the acid anhydride-modified polyamide resin (A) decreases. If it is less than 0.05, the photocurability of the acid anhydride-modified polyamide resin (A) and the sensitivity of the photosensitive resin composition when used as a photosensitive resin composition tend to decrease. The isocyanate monomer (i) having an ethylenically unsaturated group is not particularly limited, and examples thereof include 2-isocyanate ethyl methacrylate and methacryloyl isocyanate. These can be used alone or
Used in combination of more than one species.

Further, a cyclic polyvalent carboxylic acid monoanhydride (h) is added to the epoxy group-containing polyamide resin (e) and / or the epoxy group-capped polyamide resin (g).
And the total equivalent ratio of the isocyanate monomer (i) having an ethylenically unsaturated group [acid anhydride group of (h) + isocyanate group of (i) / (e) and / or hydroxyl group of (g)] is
The ratio is preferably 0.6 to 1, more preferably 0.8 to 1, and particularly preferably 1. If this total equivalent ratio [acid anhydride group of (h) + isocyanate group of (i) / (e) and / or hydroxyl group of (g)] exceeds 1, polyvalent carboxylic acid monoanhydride (h) and And / or the isocyanate monomer (i) having an ethylenically unsaturated group remains as an unreacted product, the storage stability of the photosensitive resin composition tends to decrease, and skin irritation tends to increase. If it is less than the range, developability and sensitivity of the photosensitive resin composition tend to be lowered.

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 is
(A) component anhydride modified polyamide 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 acid anhydride-modified polyamide 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 decrease, and when it exceeds 95 parts by weight, the photosensitive resin composition is used as the photosensitive element, and the surface of the flexible printed board on which the wiring is formed is thermocompression-bonded and covered. When laid, the circuit coverage and solder heat resistance tend to decrease. (A)
The blending amount of the components 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 preferably contains a crosslinking agent such as melamine resin from the viewpoint of improving solvent resistance. The amount of this cross-linking agent used is
The amount of the components (A), (B) and (C) is preferably 30 parts by weight or less based on 100 parts by weight in total. Also,
In order to further improve the flame retardancy, the photosensitive resin composition of the present invention contains, for example, tetrabromobisphenol A,
Flame retardants such as tetrabromobisphenol A oxyethylene di (meth) acrylate, tetrabromobisphenol A bisallyl ethyl ether, and polytetrabromobisphenol A terminal bromoethoxy compound can be added. Similarly, a flame retardant aid such as antimony trioxide, antimony pentoxide, barium borate and aluminum hydroxide may 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 comprises
Dyes, color formers, plasticizers, pigments, adhesion promoters and the like may be added as necessary. The amount of these used is 2% by weight based on the total amount of the components (A), (B) and (C).
The following is preferable.

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 laminating 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 the 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 exposure, if a polymer film or the like is present on the photosensitive layer, after removing it, using an alkaline aqueous solution, an aqueous developer, a known developer such as an organic solvent,
For example, the unexposed portion is removed by a known method such as spraying, oscillating dipping, brushing, or scrubbing, and development is performed. As the base of the alkaline aqueous solution, lithium, alkali hydroxide such as sodium or potassium hydroxide,
Alkali carbonates such as lithium, sodium or potassium carbonates or bicarbonates, alkali metal phosphates such as potassium phosphate and sodium phosphate, alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate are used. Particularly preferred is an aqueous solution of sodium carbonate. The pH of the aqueous alkaline solution used for development is preferably in the range of 9 to 11, and the temperature is adjusted according to the developability of the photosensitive layer. A surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be mixed in the alkaline aqueous solution.

The aqueous developing solution comprises water or an alkaline aqueous solution and at least one organic solvent. Here, as the alkaline substance, in addition to the above substances, borax, sodium metasilicate, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-
1,3-propanediol, 1,3-diaminopropanol-2-morpholine and the like can be mentioned. PH of developer
Is preferably as small as possible within the range where the resist can be sufficiently developed, more preferably in the range of pH 8 to 12, and particularly preferably in the range of pH 9 to 10.

Examples of the organic solvent 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, Examples include diethylene glycol monobutyl ether. These can be used alone or in combination of two or more. The concentration of the organic solvent is usually in the range of 2 to 90% by volume. Further, the temperature can be adjusted according to the developability. Further, a small amount of a surfactant or an antifoaming agent can be mixed in the developing solution. As the organic solvent developer used alone, 1,1,1-trichloroethane and N-methyl-2 are used.
-Pyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, γ-butyrolactone and the like can be mentioned. These organic solvents may be added in the range of 1 to 10% by volume to prevent 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.

[0043]

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, manufactured by 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.
Trade name Praxel CD220 (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.
Trade name Praxel CD220 (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 (e)) 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.
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 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 comparative carboxylic acid was 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). 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.

[0050]

[Table 1]

[0051]

[Table 2]

Synthesis Example 5 (Synthesis of Acid Anhydride-Modified Polyamide Resin) In a flask equipped with a stirrer, a thermometer, a cooling pipe and a dry air introduction pipe, 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, g-1) having a hydroxyl equivalent (resin content conversion) of 1360 and a molecular weight (design value) of 16,370 is obtained. It was Next, 8.5 parts by weight (55.9 mmol) of tetrahydrophthalic anhydride was added as the cyclic polycarboxylic acid monoanhydride (h) to (g-1) which was kept warm at 100 ° C, and the same temperature was applied. After the temperature was kept for 2 hours to complete the reaction, it was cooled to 60 ° C. While maintaining the temperature at 60 ° C., 2.9 parts by weight (18.7 mmol) of 2-isocyanate ethyl methacrylate was added as an isocyanate monomer (i) having an ethylenically unsaturated group,
After incubating at the same temperature for 4 hours to complete the reaction, cool it down,
Heating residue (220 ° C / 1 hour) 35% by weight, acid value (resin content conversion) 27.7, molecular weight (design value) 18,200, G
PC molecular weight (polystyrene equivalent) is number average of 22.0
A weight-average 55,000 acid anhydride-modified polyamide resin (hereinafter referred to as A-1) was obtained.

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 g-2, g-3, g-4) and the comparative epoxy were used. After obtaining the base-blocked polyamide resin (shown by g-5 and g-6), the composition shown in Table 4 (resin content conversion), Table 5
Acid anhydride modified polyamide resin (A-2,
It shows with A-3 and A-4. ) And a comparative acid anhydride-modified polyamide resin (indicated by A-5 and A-6) were obtained.

Synthesis Example 6 (Synthesis of Acid Anhydride-Modified Polyamide-Based Resin) In a synthesis example 4, a flask equipped with a stirrer, a thermometer, a cooling pipe and a dry air introduction pipe was used as the epoxy group-containing polyamide-based resin (e). Obtained (e-1) 100 parts by weight (resin content conversion, 6.17 mmol), methoquinone (radical polymerization inhibitor) 0.21 parts by weight and N, N-dimethylbenzylamine (catalyst) 2.9 parts by weight ( (1% by weight of the solution of (e)) was charged and the temperature was raised to 100 ° C. under aeration of dry air.
After the temperature was raised, 8.5 parts by weight (55.9 mmol) of tetrahydrophthalic anhydride was added as a cyclic polycarboxylic acid monoanhydride (h), and the mixture was kept at the same temperature for 2 hours to complete the reaction. , Cooled to 60 ° C. Isocyanate monomer (i) further having an ethylenically unsaturated group under heat retention at 60 ° C
2-isocyanatoethyl methacrylate as 2.9
Part by weight (18.7 mmol) was added, and the mixture was kept at the same temperature for 4 hours to complete the reaction, then cooled, and the heating residue (22
35% by weight, acid value (converted to resin content) 23.
1. Acid anhydride-modified polyamide resin (hereinafter referred to as A-7) having a molecular weight (design value) of 18,000, a GPC molecular weight (polystyrene conversion value) of 25,000 on a number average and 69,000 on a weight average. Got Table 4 shows the compounding (resin content conversion) of the obtained acid anhydride-modified polyamide resin, and Table 5 shows its properties.

Synthetic Example 7 (Synthesis of Acid Anhydride-Modified Polyamide Resin) A synthetic resin of Example 4 was prepared as the epoxy group-containing polyamide resin (e) in a flask equipped with a stirrer, a thermometer, a cooling pipe and a dry air introducing pipe. 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, g-1) having a hydroxyl equivalent (resin content conversion) of 1360 and a molecular weight (design value) of 16,370 is obtained. It was Then, 11.3 parts by weight (74.3 mmol) of tetrahydrophthalic anhydride was added as the cyclic polycarboxylic acid monoanhydride (h) to (g-1) which was kept warm at 100 ° C. After incubating at room temperature for 4 hours to complete the reaction, cool and heat the residue (220 ℃
/ 1 hour) 35% by weight, acid value (resin content conversion) 36.9,
Molecular weight (design value) 18,210, GPC molecular weight (polystyrene conversion value) number average 23,000, weight average 5
7,000 acid anhydride-modified polyamide resins (hereinafter referred to as A
It is written as -8. ) Got. Table 4 shows the compounding (resin content conversion) of the obtained acid anhydride-modified polyamide resin, and Table 5 shows its properties.

The units of the compounding amounts in Tables 3 and 4 are
Parts by weight, THPAC is tetrahydrophthalic anhydride, IEM is 2-isocyanatoethylmethacrylate, γ-BL is γ-butyrolactone, DMF is N,
N-dimethylformamide.

[0057]

[Table 3]

[0058]

[Table 4]

[0059]

[Table 5]

Example 1 The materials in Table 6 were blended to prepare a solution of a photosensitive resin composition.

[Table 6]

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 9. Show.

Circuit embedding property A substrate for a flexible printed board (made by Nikkan Industry 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 and 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 characteristics 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.
Was exposed to a predetermined amount using an HMW-201GX type exposure machine manufactured by Oak Manufacturing Co., Ltd., and further developed with an aqueous solution containing 0.8% by weight of borax and 20% by volume of diethylene glycol monobutyl ether as an aqueous developer. The sensitivity was defined as the exposure amount required to obtain 8 step tablet steps.

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 test negative mask was brought into close contact with the sample polyethylene terephthalate film obtained by laminating a photosensitive element on a flexible printed circuit 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 an aqueous solution containing 0.8% by weight of borax and 20% by volume of diethylene glycol monobutyl ether was used as an aqueous developer, and spray development was performed at 40 ° C. for 70 seconds. It was dried at 80 ° C. for 10 minutes. Then, using an ultraviolet irradiation device manufactured by Toshiba Denshi Co., Ltd., 3 J / cm
Ultraviolet irradiation of 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 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 endurance 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 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-retardant flexible printed circuit board (manufactured by Nikkan Industry Co., Ltd.,
Using a vacuum laminator (Hitachi Chemical Co., Ltd., trade name VLM-1 type) on an adhesive-attached polyimide base material with the copper foil of trade name F30VC125RC11) removed by etching, heat shoe temperature 120 ° C., laminating speed 0.5
m / s, atmospheric pressure 4000 Pa or less, pressure bonding pressure 2.94 × 10
^The photosensitive element was laminated at ⁵ Pa while peeling off the polyethylene film, and exposed so as to obtain 8 step tablet stages. After left at room temperature for 1 hour, the sample polyethylene terephthalate film was peeled off, and an aqueous solution containing 0.8% by weight of borax and 20% by volume of diethylene glycol monobutyl ether was used as an aqueous developer, and spray development was performed at 40 ° C. for 70 seconds. It was dried at 80 ° C. for 10 minutes. Next, using an ultraviolet irradiator manufactured by Toshiba Denshi Co., Ltd., irradiate with 3 J / cm ² of ultraviolet light and further 150 ° C.
Was heat-treated for 40 minutes to obtain a flexible printed board on which a cover lay was formed. The flexible printed board on which the obtained cover lay was formed was evaluated for flame retardancy according to UL94 standard (VTM method).

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 to 11 and Comparative Examples 1 to 6, except that the acid anhydride-modified polyamide resin, the photopolymerizable unsaturated compound and the additives used in Example 1 were changed to those shown in Tables 7 and 8. In the same manner as in Example 1, a photosensitive element was produced, processed into a coverlay in the same manner as in Example 1, evaluated, and the results are shown in Tables 9 and 10. Table 7
And in Table 8, 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.

[0074]

[Table 7]

[0075]

[Table 8]

[0076]

[Table 9]

[0077]

[Table 10]

As is clear from Tables 9 and 10, 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.

[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 C08F 299/02 C08F 299/02 C08K 5/00 C08K 5/00 C08L 77/00 KKU C08L 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 7/038 503 7/038 503 504 504 H05K 1/03 670 H05K 1/03 670A 3 / 28 3/28 D // C08G 18/67 NFA C08G 18/67 NFA (72) Inventor Hiroshi Nishizawa 4-13-1, Higashimachi, Hitachi City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Ibaraki Research Institute

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. Epoxy group-containing polyamide resin (e) and / or (e) obtained by reacting under conditions of 1 or more
With respect to the epoxy group-capped polyamide resin (g) obtained by reacting the monocarboxylic acid (f) under the condition that the equivalent ratio [carboxyl group of (f) / epoxy group of (e)] is 1 or more. And cyclic polycarboxylic acid monoanhydride (h)
The equivalent ratio [acid anhydride group of (h) / (e) and / or hydroxyl group of (g)] is in the range of 0.1 to 2, and the isocyanate monomer (i) having an ethylenically unsaturated group is equivalent. Ratio [(i) of isocyanate groups / (e) and / or (g)
[Hydroxyl group] of 2 or less], and an acid anhydride-modified polyamide resin obtained by reacting under conditions of (2), (B) photopolymerizable unsaturated compound having at least one ethylenically unsaturated group at the end, and (C) A photosensitive resin composition comprising a photopolymerization initiator that generates free radicals when irradiated 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.