JP6050180B2 - Laminated structure and flexible printed wiring board - Google Patents

Description

  The present invention relates to a laminated structure useful as an insulating film of a flexible printed wiring board and a flexible printed wiring board.

  In recent years, it has become necessary to reduce the space of circuit boards due to the small size and thinness of electronic devices due to the spread of smartphones and tablet terminals. For this reason, flexible prints that can be folded and stored have expanded uses of wiring boards, and such flexible prints are required to have higher reliability than ever before.

  On the other hand, as an insulating film to ensure the insulation reliability of flexible printed wiring boards, a cover based on polyimide with excellent mechanical properties such as heat resistance and flexibility is used for the bent part (bent part). Lay is used (for example, see Patent Documents 1 and 2), and the mounting part (non-bent part) uses a photosensitive resin composition that is excellent in electrical insulation and solder heat resistance and can be finely processed. Is widely adopted.

  That is, a polyimide-based coverlay having excellent mechanical properties such as heat resistance and flexibility is not suitable for fine wiring because it requires processing by die punching. Therefore, it is necessary to partially use an alkali developing type photosensitive resin composition (solder resist) that can be processed by photolithography in a chip mounting portion that requires fine wiring.

Japanese Patent Application Laid-Open No. Sho 62-263692 Japanese Unexamined Patent Publication No. 63-110224

  As described above, the flexible print has a problem in that it is inferior in cost and workability in the manufacturing process of the wiring board, because it has to employ a mixed mounting process of a process of attaching a cover lay and a process of forming a solder resist.

  Conventionally, it has been proposed to apply an insulating film as a solder resist as a coverlay of a flexible printed wiring board for such a mixed mounting process. However, such a resin composition for a solder resist has insufficient reliability such as impact resistance and flexibility as a cover lay, and a process for collectively forming a bent portion (bent portion) and a mounting portion (non-bent portion). Has not yet been put to practical use. In addition, since the resin composition for solder resist is accompanied by curing shrinkage due to acrylic photopolymerization, there is a problem in dimensional stability such as warping of a flexible wiring board.

  On the other hand, as a photosensitive polyimide capable of achieving both alkali solubility and mechanical properties, a method of thermally ring-closing after patterning using a polyimide precursor has been proposed. However, problems remain in the workability of wiring board manufacture, such as requiring high-temperature treatment, and it has not yet been put into practical use.

  In addition, it is conceivable to apply an insulating film as a coverlay as a solder resist for a flexible printed wiring board. However, such a coverlay film requires a complicated process for pattern formation, and is not suitable for punching holes by punching. There is a problem that it is difficult to cope with the formation of a fine pattern due to low processing accuracy and oozing of the resin during thermocompression bonding.

  Accordingly, an object of the present invention is to provide an insulating film for a flexible printed wiring board that is excellent in reliability and processing accuracy such as impact resistance, bendability, and low warpage, and has excellent workability. Laminated structure suitable for the batch formation process of mounting parts (non-bent parts) and flexible prints that have a cured product as a protective film, such as a coverlay or solder resist, with excellent reliability such as impact resistance and flexibility It is to provide a wiring board.

As a result of intensive research aimed at realizing the above object, the inventors have completed the present invention having the following contents.
That is, the laminated structure of the present invention comprises a resin layer (A) made of an alkali developing resin composition, and a resin layer (B) laminated on a flexible printed wiring board via the resin layer (A). The resin layer (B) is composed of a photosensitive thermosetting resin composition containing an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound. To do.

  In the laminated structure of the present invention, it is preferable that both the resin layer (A) and the resin layer (B) can be patterned by light irradiation.

  Furthermore, the laminated structure of the present invention can be used for at least one of a bent portion and a non-bent portion of the flexible printed wiring board. Also, the cover lay of the flexible printed wiring board, the solder resist, and the interlayer insulating material Can be used as at least one of the applications.

  The dry film of the present invention is characterized in that at least one surface of the laminated structure is supported or protected by a film.

The flexible printed wiring board of the present invention has an insulating film formed by forming a layer of the laminated structure on the flexible printed wiring board, patterning by light irradiation, and forming the pattern in a batch with a developer. It is a feature.
The flexible printed wiring board of the present invention is formed by sequentially forming the resin layer (A) and the resin layer (B) without using the laminated structure according to the present invention, and then patterning by light irradiation. The pattern may be formed in a lump.
In the present invention, the “pattern” means a patterned cured product, that is, an insulating film.

  According to the present invention, an insulating film for a flexible printed wiring board having excellent reliability and processing accuracy such as impact resistance, bendability, and low warpage, and excellent workability, particularly a bent portion (bend portion) and mounting. A laminated structure suitable for the batch formation process of parts (non-bent parts) and its cured product as an insulating film, for example, a cover lay, solder resist, or interlayer insulating layer, for reliability such as impact resistance and flexibility An excellent flexible printed wiring board can be provided.

It is process drawing which shows typically an example of the manufacturing method of the flexible printed wiring board of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
(Laminated structure)
The laminated structure of the present invention has a laminated structure having a resin layer (A) made of an alkali developing resin composition and a resin layer (B) laminated on a flexible printed wiring board via the resin layer (A). The resin layer (B) is composed of a photosensitive thermosetting resin composition containing an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound. is there.

  Such a laminated structure of the present invention can be laminated on a flexible printed wiring board, and can be patterned by light irradiation on the flexible printed wiring board, and patterns can be collectively formed by development. It becomes.

  According to such a laminated structure of the present invention, (1) a resin having an imide ring in the molecule is used as the resin layer (B), and (2) an alkali-soluble resin and a thermally reactive compound are used. This layer functions as a reinforcing layer by using a composition utilizing the addition reaction, and even if a resin layer (A) made of a conventional solder resist composition or an interlayer insulating material is used, impact resistance and bending It is possible to provide an insulating film for a flexible printed wiring board that is excellent in reliability such as reliability and low warpage and processing accuracy and excellent in workability.

  The laminated structure of the present invention has a resin layer (A) and a resin layer (B) in order on a flexible printed wiring board in which a copper circuit is formed on a flexible substrate, and at least the resin layer (B) is irradiated with light. Can be patterned, and the resin layer (A) and the resin layer (B) can collectively form a pattern by development.

(Resin layer (A) constituting the laminated structure)
(Alkali developable resin composition constituting the resin layer (A))
The alkali-developable resin composition constituting the resin layer (A) is a composition containing a resin that contains one or more functional groups among phenolic hydroxyl groups, thiol groups, and carboxyl groups and that can be developed with an alkaline solution. Any photocurable resin composition or thermosetting resin composition may be used. Preferred examples include a resin composition containing a compound having two or more phenolic hydroxyl groups, a carboxyl group-containing resin, a compound having a phenolic hydroxyl group and a carboxyl group, and a compound having two or more thiol groups. It is done.

  For example, a light containing a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin, a compound having an ethylenically unsaturated bond, a photopolymerization initiator, and a heat-reactive compound conventionally used as a solder resist composition A curable thermosetting resin composition is mentioned.

  Here, as the carboxyl group-containing resin or the carboxyl group-containing photosensitive resin, the compound having an ethylenically unsaturated bond, the photopolymerization initiator, and the heat-reactive compound, known and commonly used ones are used.

(Resin layer (B) constituting the laminated structure)
(Photosensitive thermosetting resin composition constituting the resin layer (B))
The photosensitive thermosetting resin composition constituting the resin layer (B) includes an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound.

(Alkali-soluble resin having an imide ring)
In the present invention, the alkali-soluble resin having an imide ring is one having an alkali-soluble group such as a carboxyl group or an acid anhydride group and an imide ring. For introducing the imide ring into the alkali-soluble resin, a known and usual method can be used. For example, the resin obtained by making a carboxylic anhydride component react with an amine component and / or an isocyanate component is mentioned. The imidization may be performed by thermal imidization or chemical imidization, and these can be used in combination.

  Here, examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydrides and tricarboxylic acid anhydrides, but are not limited to these acid anhydrides, and acid anhydrides that react with amino groups or isocyanate groups. Any compound having a physical group and a carboxyl group can be used, including derivatives thereof. These carboxylic anhydride components may be used alone or in combination.

  Examples of the tetracarboxylic acid anhydride include pyromellitic dianhydride, 3-fluoropyromellitic dianhydride, 3,6-difluoropyromellitic dianhydride, 3,6-bis (trifluoromethyl) pyro Merit acid dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic acid Anhydride, 2,2′-difluoro-3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5′-difluoro-3,3 ′, 4,4′-biphenyltetracarboxylic acid Anhydride, 6,6′-difluoro-3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 5,5 ′, 6,6′-hexafluoro-3,3 ′ , 4,4'-biphenyltet Carboxylic dianhydride, 2,2′-bis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5′-bis (trifluoromethyl) -3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 6,6′-bis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′ , 5,5′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 6,6′-tetrakis (trifluoromethyl) -3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride , And 2,2 ', 5,5', 6,6 -Hexakis (trifluoromethyl) -3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3 ", 4,4 "-Terphenyltetracarboxylic dianhydride, 3,3 '", 4,4' "-quaterphenyltetracarboxylic dianhydride, 3,3" ", 4,4" "-kinkphenyltetracarboxylic acid Dianhydride, methylene-4,4′-diphthalic dianhydride, 1,1-ethynylidene-4,4′-diphthalic dianhydride, 2,2-propylidene-4,4′-diphthalic dianhydride 1,2-ethylene-4,4′-diphthalic dianhydride, 1,3-trimethylene-4,4′-diphthalic dianhydride, 1,4-tetramethylene-4,4′-diphthalic acid Anhydride, 1,5-pentamethylene-4,4'-diph Talic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, difluoromethylene-4,4′-diphthal Acid dianhydride, 1,1,2,2-tetrafluoro-1,2-ethylene-4,4′-diphthalic dianhydride, 1,1,2,2,3,3-hexafluoro-1, 3-trimethylene-4,4′-diphthalic dianhydride, 1,1,2,2,3,3,4,4-octafluoro-1,4-tetramethylene-4,4′-diphthalic dianhydride 1,1,2,2,3,3,4,4,5,5-decafluoro-1,5-pentamethylene-4,4′-diphthalic dianhydride, thio-4,4′- Diphthalic dianhydride, sulfonyl-4,4′-diphthalic dianhydride, 1,3-bis (3,4-dicarboxyphene) ) -1,1,3,3-tetramethylsiloxane dianhydride, 1,3-bis (3,4-dicarboxyphenyl) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenyl) ) Benzene dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,3-bis [ 2- (3,4-Dicarboxyphenyl) -2-propyl] benzene dianhydride, 1,4-bis [2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride, bis [ 3- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, bis [4- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, 2,2-bis [3- (3,4- Dicarboxyphenoxy Phenyl] propane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,2-bis [3- (3,4-dicarboxyphenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, bis (3,4- Dicarboxyphenoxy) dimethylsilane dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) -1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalene Tetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic Acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid Anhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3 ′ , 4,4′-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4′-bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethynylidene-4,4′-bis (cyclohexane) San-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1,1,3,3,3 -Hexafluoro-2,2-propylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride Thio-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 3,3 ′ -Difluorooxy-4,4'-diphthalic dianhydride, 5,5'-difluorooxy-4,4'-diphthalic dianhydride, 6,6'-difluorooxy-4,4'-diphthalic acid Anhydride, 3, 3 ', 5, 5', 6 6′-hexafluorooxy-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 5,5′-bis (tri Fluoromethyl) oxy-4,4′-diphthalic dianhydride, 6,6′-bis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 3,3 ′, 5,5′- Tetrakis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 3,3 ′, 6,6′-tetrakis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 5, 5 ', 6,6'-tetrakis (trifluoromethyl) oxy-4,4'-diphthalic dianhydride, 3,3', 5,5 ', 6,6'-hexakis (trifluoromethyl) oxy- 4,4'-diphthalic dianhydride, 3,3'-diflu Orosulfonyl-4,4′-diphthalic dianhydride, 5,5′-difluorosulfonyl-4,4′-diphthalic dianhydride, 6,6′-difluorosulfonyl-4,4′-diphthalic dianhydride 3,3 ′, 5,5 ′, 6,6′-hexafluorosulfonyl-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) sulfonyl-4,4′- Diphthalic dianhydride, 5,5′-bis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 6,6′-bis (trifluoromethyl) sulfonyl-4,4′-diphthalic acid Dianhydride, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 6,6′-tetrakis (trifluoromethyl) sulfonyl -4,4'-diphthalate Dianhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexakis ( Trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3′-difluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 5,5′-difluoro -2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 6,6'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3, 3 ′, 5,5 ′, 6,6′-hexafluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) -2, 2-perfluoropropylidene-4,4'-diphthalate Acid dianhydride, 5,5′-bis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 6,6′-difluoro-2,2-perfluoro Propylidene-4,4′-diphthalic dianhydride, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride 3,3 ′, 6,6′-tetrakis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 5,5 ′, 6,6′-tetrakis ( Trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexakis (trifluoromethyl) -2,2 -Perfluoropropylidene-4,4'-diph Talic dianhydride, 9-phenyl-9- (trifluoromethyl) xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis (trifluoromethyl) xanthene-2,3 6,7-tetracarboxylic dianhydride, bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 9,9-bis [4- (3 , 4-Dicarboxy) phenyl] fluorene dianhydride, 9,9-bis [4- (2,3-dicarboxy) phenyl] fluorene dianhydride, ethylene glycol bistrimellitic dianhydride, 1,2- ( Ethylene) bis (trimellitic anhydride), 1,3- (trimethylene) bis (trimellitic anhydride), 1,4- (tetramethylene) bis (trimellitic anhydride), 1,5- (pentamethylene) bis (trimetic anhydride) Retate anhydride), 1,6- (hexamethylene) bis (trimellitic anhydride), 1,7- (heptamethylene) bis (trimellitate anhydride), 1,8- (octamethylene) bis (trimellitic anhydride), 1,9- (nonamethylene) bis (trimellitic anhydride), 1,10- (decamethylene) bis (trimellitic anhydride), 1,12- (dodecamethylene) bis (trimellitic anhydride), 1,16- (hexadeca) Methylene) bis (trimellitate anhydride), 1,18- (octadecamethylene) bis (trimellitate anhydride), and the like.

  Examples of the tricarboxylic acid anhydride include trimellitic acid anhydride and nuclear hydrogenated trimellitic acid anhydride.

  Examples of the amine component include diamines such as aliphatic diamines and aromatic diamines, and polyvalent amines such as aliphatic polyether amines, but are not limited to these amines. These amine components may be used alone or in combination.

  Examples of the diamine include p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, 2,5-toluenediamine, 2,6-toluenediamine, 3,5-diaminobenzoic acid, One diamine nucleus diamine such as 2,5-diaminobenzoic acid and 3,4-diaminobenzoic acid, diaminodiphenyl ether such as 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, and 3,4′-diaminodiphenyl ether 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl ) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiph Nilmethane, 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4, 4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-tolidine), 2,2'-dimethylbenzidine (m-tolidine), 3,3'-dimethoxybenzidine, 2 , 2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4 , 4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyls Hong, 3,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,3′-diamino-4,4′-dichlorobenzophenone, 3,3′-diamino- 4,4′-dimethoxybenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) -1, 1,1,3,3,3-hexafluoropropane, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfone Xoxide, 4,4′-diaminodiphenyl sulfoxide, 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 3,3 ′ -Two diamine diamines such as diamino-4,4'-dihydroxydiphenylsulfone, 1,3-bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4 -Bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) -4-trifluoromethylbenzene, 3,3 -Diamino-4- (4-phenyl) phenoxybenzophenone, 3,3'-diamino-4,4'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenyl sulfide) benzene, 1, 3-bis (4-aminophenyl sulfide) benzene, 1,4-bis (4-aminophenyl sulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenyl) Sulfone) benzene, 1,4-bis (4-aminophenylsulfone) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) Isopropyl] benzene, 1,4-bis [2- (4-aminophenyl) isopropyl] benzene, 1,3-bis (4-amino) (3-hydroxyphenoxy) benzene and other benzene nucleus three diamines, 3,3′-bis (3-aminophenoxy) biphenyl, 3,3′-bis (4-aminophenoxy) biphenyl, 4,4′-bis ( 3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [3- (4-aminophenoxy) ) Phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophen Noxy) phenyl] ketone, bis [3- (3-aminophenoxy) phenyl] sulfide, bis [3- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [ 4- (4-aminophenoxy) phenyl] sulfide, bis [3- (3-aminophenoxy) phenyl] sulfone, bis [3- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) Phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [3- (3-aminophenoxy) phenyl] methane, bis [3- (4-aminophenoxy) phenyl] methane, bis [4- (3-Aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] Tan, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-amino Phenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3 , 3-hexafluoropropane, 2,2-bis [3- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (3 -Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3 3-hexafluoropropane, etc. Aromatic diamine such as four diamines of benzene nucleus, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7- Examples include aliphatic diamines such as diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, and 1,2-diaminocyclohexane. Examples of the aliphatic polyether amine include ethylene glycol and / or propylene glycol-based polyvalent amine.

Diisocyanates such as aromatic diisocyanates and isomers and multimers, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general-purpose diisocyanates can be used as the isocyanate component. It is not limited. These isocyanate components may be used alone or in combination.
Examples of diisocyanates include aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, biphenyl diisocyanate, diphenyl sulfone diisocyanate, diphenyl ether diisocyanate, and isomers, multimers, hexamethylene diisocyanate, isophorone. Aliphatic diisocyanates such as diisocyanate, dicyclohexylmethane diisocyanate, and xylylene diisocyanate,
Or the alicyclic diisocyanates and isomers which hydrogenated the said aromatic diisocyanate, or other general purpose diisocyanates are mentioned.

  The alkali-soluble resin having an imide ring as described above may have an amide bond. This may be an amide bond obtained by reacting an isocyanate and a carboxylic acid, or may be caused by other reaction. Furthermore, you may have the coupling | bonding which consists of another addition and condensation.

  In addition, for the introduction of the imide ring into the alkali-soluble resin, a known and commonly used alkali-soluble polymer, oligomer or monomer having a carboxyl group and / or an acid anhydride group may be used. It may be a resin obtained by reacting an alkali-soluble resin alone or in combination with the above carboxylic anhydride component and reacting with the above amine / isocyanate.

  In the synthesis of such an alkali-soluble resin having an alkali-soluble group and an imide ring, a known and commonly used organic solvent can be used. Such an organic solvent is not particularly limited as long as it is a solvent that does not react with the carboxylic acid anhydrides, amines, and isocyanates that are raw materials and that dissolves these raw materials, and the structure is not particularly limited. Specifically, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone , Cyclic ester solvents such as α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, lactam solvents such as caprolactam, ether solvents such as dioxane, glycol solvents such as triethylene glycol, m-cresol, Phenolic solvents such as p-cresol, 3-chlorophenol, 4-chlorophenol, 4-methoxyphenol, 2,6-dimethylphenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl Sulfo Sid, such as tetramethylurea. Furthermore, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran , Dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, petroleum naphtha solvents, etc. Can also be used. Of these, aprotic solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, and γ-butyrolactone are preferred because of the high solubility of the raw materials.

  The alkali-soluble resin having an alkali-soluble group such as a carboxyl group or an acid anhydride group and an imide ring as described above has an acid value of 20 to 200 mgKOH / g in order to cope with the photolithography process. Is more preferable, and 60 to 150 mgKOH / g is more preferable. When the acid value is 20 mgKOH / g or more, the solubility in alkali increases, the developability becomes good, and further, the degree of crosslinking with the thermosetting component after light irradiation becomes high, so that sufficient development contrast is obtained. be able to. When the acid value is 200 mgKOH / g or less, so-called heat fogging in a PEB (POST EXPOSURE BAKE) step after light irradiation described later can be suppressed, and the process margin is increased.

The molecular weight of the alkali-soluble resin is preferably from 1,000 to 100,000, more preferably from 2,000 to 50,000, considering developability and cured coating properties.
When the molecular weight is 1,000 or more, sufficient development resistance and cured properties can be obtained after exposure and PEB. On the other hand, when the molecular weight is 100,000 or less, alkali solubility increases and developability improves.

(Photobase generator)
The photobase generator used in the resin layer (B) is used as a catalyst for the polymerization reaction of a thermoreactive compound, which will be described later, when the molecular structure is changed by light irradiation such as ultraviolet light or visible light, or the molecule is cleaved. It is a compound that produces one or more basic substances that can function. Examples of basic substances include secondary amines and tertiary amines.
Examples of photobase generators include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic amino groups, nitrobenzyl carbamate groups, and alkoxyoxybenzyl carbamates. And compounds having a substituent such as a group. Of these, oxime ester compounds and α-aminoacetophenone compounds are preferred. As the α-aminoacetophenone compound, those having two or more nitrogen atoms are particularly preferable.

  Other photobase generators include WPBG-018 (trade name: 9-anthrylmethylN, N'-diethylcarbamate), WPBG-027 (trade name: (E) -1- [3- (2-hydroxyphenyl) -2-propenoyl ] piperidine), WPBG-082 (trade name: guanidinium2- (3-benzoylphenyl) propionate), WPBG-140 (trade name: 1- (anthraquinon-2-yl) ethyl imidazolecarboxylate), and the like can also be used.

  The α-aminoacetophenone compound has a benzoin ether bond in the molecule, and when irradiated with light, cleavage occurs in the molecule to produce a basic substance (amine) that exhibits a curing catalytic action. Specific examples of the α-aminoacetophenone compound include (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane (Irgacure 369, trade name, manufactured by BASF Japan Ltd.) and 4- (methylthiobenzoyl) -1-methyl. -1-morpholinoethane (Irgacure 907, trade name, manufactured by BASF Japan Ltd.), 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl]- A commercially available compound such as 1-butanone (Irgacure 379, trade name, manufactured by BASF Japan Ltd.) or a solution thereof can be used.

  Any oxime ester compound can be used as long as it is a compound that generates a basic substance by light irradiation. Examples of such oxime ester compounds include CGI-325, Irgacure OXE01, Irgacure OXE02 manufactured by BASF Japan, N-1919, and NCI-831 manufactured by Adeka. Moreover, the compound which has two oxime ester groups in the molecule | numerator described in the patent 4344400 gazette can also be used suitably.

  In addition, JP-A-2004-359639, JP-A-2005-097141, JP-A-2005-220097, JP-A-2006-160634, JP-A-2008-094770, JP-A-2008-509967, Specific examples include carbazole oxime ester compounds described in JP2009-040762A and JP2011-80036A.

  Such a photobase generator may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the photobase generator in the thermosetting resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the thermoreactive compound. It is. In the case of 0.1 parts by mass or more, the development resistance contrast of the light irradiated part / non-irradiated part can be favorably obtained. Moreover, in 40 mass parts or less, hardened | cured material characteristic improves.

(Thermo-reactive compound)
The heat-reactive compound used in the resin layer (B) is a resin having a functional group that can be cured by heat. An epoxy resin, a polyfunctional oxetane compound, etc. are mentioned.

  The epoxy resin is a resin having an epoxy group, and any known one can be used. Examples thereof include a bifunctional epoxy resin having two epoxy groups in the molecule, and a polyfunctional epoxy resin having many epoxy groups in the molecule. In addition, a hydrogenated bifunctional epoxy compound may be used.

  Polyfunctional epoxy compounds include bisphenol A type epoxy resin, brominated epoxy resin, novolac type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, alicyclic ring Epoxy resin, trihydroxyphenylmethane type epoxy resin, bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin, bisphenol A novolak type epoxy resin, tetraphenylolethane type epoxy resin, heterocyclic epoxy Resin, diglycidyl phthalate resin, tetraglycidyl xylenoyl ethane resin, naphthalene group-containing epoxy resin, epoxy resin having dicyclopentadiene skeleton, glycidyl meta Acrylate copolymer epoxy resins, copolymerized epoxy resins of cyclohexylmaleimide and glycidyl methacrylate, and a CTBN modified epoxy resin.

  Other liquid bifunctional epoxy resins include vinylcyclohexene diepoxide, (3 ′, 4′-epoxycyclohexylmethyl) -3,4-epoxycyclohexanecarboxylate, and (3 ′, 4′-epoxy-6′-methyl). And alicyclic epoxy resins such as (cyclohexylmethyl) -3,4-epoxy-6-methylcyclohexanecarboxylate. These epoxy resins may be used individually by 1 type, and may use 2 or more types together.

  Examples of the polyfunctional oxetane compound include bis [(3-methyl-3-oxetanylmethoxy) methyl] ether, bis [(3-ethyl-3-oxetanylmethoxy) methyl] ether, 1,4-bis [(3-methyl -3-Oxetanylmethoxy) methyl] benzene, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3-oxetanyl) In addition to polyfunctional oxetanes such as methyl acrylate, (3-methyl-3-oxetanyl) methyl methacrylate, (3-ethyl-3-oxetanyl) methyl methacrylate and oligomers or copolymers thereof, oxetane alcohol and novolak resin, Poly (p-hydroxystyrene), cardo-type bisphenol Le ethers, calixarenes, calix resorcin arenes, or the like ethers of a resin having a hydroxyl group such as silsesquioxane and the like. In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate is also included.

  As a compounding quantity of the said thermoreactive compound, equivalent ratio (alkali-soluble groups, such as a carboxyl group: thermal-reactive groups, such as an epoxy group) with alkali-soluble resin is 1: 0.1 to 1:10. It is preferable. By setting the blending ratio in such a range, development becomes favorable and a fine pattern can be easily formed. The equivalent ratio is more preferably 1: 0.2 to 1: 5.

(Polymer resin)
The resin composition used in the resin layer (A) and the resin layer (B) as described above is blended with a known and commonly used polymer resin for the purpose of improving the flexibility and dryness of the cured product obtained. can do. Examples of such polymer resins include cellulose-based, polyester-based, phenoxy-resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, polyamide-based, polyamide-imide-based binder polymers, block copolymers, and elastomers.
This polymer resin may be used individually by 1 type, and may use 2 or more types together.

(Inorganic filler)
In addition, the resin composition used in the resin layer (A) and the resin layer (B) is blended with an inorganic filler in order to suppress curing shrinkage of the cured product and improve properties such as adhesion and hardness. Can do. Examples of such inorganic fillers include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, Neuburg Sicilius Earth etc. are mentioned.

(Coloring agent)
Furthermore, a well-known and usual colorant can be mix | blended with the resin composition used in the resin layer (A) and the resin layer (B).
Conventionally, at the edge portion of a copper circuit in a printed wiring board, when the coloring power of the pattern layer is insufficient, copper is discolored in the heat history after the formation of the pattern layer, and only a thin portion appears discolored in appearance. Typical thermal history includes marking thermosetting, warping, preheating before mounting, mounting, and the like.
For this reason, conventionally, a problem has been solved that only the edge portion of the copper circuit looks discolored by adding a large amount of colorant to the pattern layer to enhance the coloring power.
However, since the colorant has light absorptivity, it prevents light from penetrating to the deep part. As a result, in a composition containing a colorant, undercut is likely to occur, and it is difficult to obtain sufficient adhesion.

On the other hand, in the resin composition used in the present invention, the base can be sufficiently cured to the deep part of the resin layer by the chemical growth of the base to the deep part.
Therefore, according to the resin composition used in the present invention, even when a colorant is contained, a pattern layer having excellent copper circuit concealing property and excellent adhesion can be formed.

(Organic solvent)
For the resin composition used in the resin layer (A) and the resin layer (B), an organic solvent should be used for preparing the resin composition and adjusting the viscosity for application to a substrate or carrier film. Can do.
Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. Such an organic solvent may be used individually by 1 type, and may be used as a 2 or more types of mixture.

(Other optional ingredients)
The resin composition used in the resin layer (A) and the resin layer (B) can further contain components such as a mercapto compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber as necessary. As these, those commonly used in the field of electronic materials can be used. In addition, known and commonly used thickeners such as finely divided silica, hydrotalcite, organic bentonite, montmorillonite, defoamers and / or leveling agents such as silicones, fluorines and polymers, silane coupling agents, rust inhibitors Known and conventional additives such as can be blended.

(Production method)
Next, a method for producing the flexible printed wiring board of the present invention from the laminated structure of the present invention will be described based on the process diagram of FIG.
1 includes a resin layer 3 made of an alkali developing resin composition containing a carboxyl group-containing resin and the like, one or more imide rings and one or more carboxyl groups in one molecule on the resin layer 3. A laminated structure comprising a resin layer 4 made of an alkali-developable photosensitive thermosetting resin composition containing an alkali-soluble resin having a photobase generator and a heat-reactive compound. The state currently formed in the flexible printed wiring base material 1 in which 2 was formed is shown.

  The conventional resin layer of only the solder resist layer has poor mechanical properties such as impact resistance and flex resistance. However, according to the laminated structure of the present invention, (1) an imide ring is formed as the resin layer 4. By using a resin present in the molecule, and (2) using a composition utilizing an addition reaction between an alkali-soluble resin and a heat-reactive compound, this layer functions as a reinforcing layer. Provided is an insulating film for a flexible printed wiring board that is excellent in reliability and processing accuracy such as impact resistance, flexibility, low warpage and the like, and excellent in workability even when the resin layer 3 made of a resist composition is used. be able to.

  In the light irradiation step of FIG. 1, a mask 5 is disposed on the resin layer 4 and light irradiation is performed in a negative pattern, thereby activating the photobase generator contained in the thermosetting resin composition to perform light irradiation. The process of hardening a part is shown. In this step, a basic substance (hereinafter sometimes abbreviated as “base”) is generated from the photobase generator, the photobase generator is destabilized by the generated base, and further a base is generated. . Thus, it is thought that it can fully harden to the deep part of a resin layer by chemically growing to the deep part of a resin layer by generating a base. In subsequent thermosetting, this base acts as a catalyst for the addition reaction between the alkali-developable resin and the heat-reactive compound, and the addition reaction proceeds. Therefore, in the light irradiation part, the resin layer is sufficiently deep. To harden. Thus, since hardening of the curable resin composition in this invention is a ring-opening reaction of the epoxy by thermal reaction, distortion and hardening shrinkage | contraction can be suppressed compared with the case where it progresses by photoreaction.

  The heating process of FIG. 1 shows the process of hardening a light irradiation part by heating a resin layer after a light irradiation process. Thereby, the resin layer can be sufficiently cured to a deep portion with the base generated in the light irradiation step, and a pattern layer having excellent curing characteristics can be obtained.

The developing process of FIG. 1 shows a process of forming a negative pattern layer by removing an unirradiated part by developing with an alkaline aqueous solution.
Furthermore, the 2nd light irradiation process of FIG. 1 shows the process of irradiating an ultraviolet-ray as needed in order to activate the remaining photobase generator and to generate a base.
Furthermore, the thermosetting process of FIG. 1 shows the process of performing thermosetting (post-cure) as needed in order to fully thermoset the pattern layer.
Hereinafter, each step will be described in detail.

[Lamination process]
A lamination process is a process of forming the laminated structure of the present invention on a substrate. Here, each resin layer constituting the laminated structure is formed by, for example, sequentially applying the resin composition constituting the resin layers 3 and 4 to the substrate and drying the resin layers 3 and 4. Or it can form by the method of laminating | stacking the thing which made the resin composition which comprises the resin layers 3 and 4 each in the form of the dry film on a base material one by one. Moreover, you may form by the method of laminating what was made into the dry film form of 2 layer structure on a base material.

  The application method of the resin composition to the substrate may be a known method such as a blade coater, a lip coater, a comma coater, or a film coater. Also, the drying method is a method using a hot-air circulation type drying furnace, IR furnace, hot plate, convection oven, etc., equipped with a heat source of the heating method by steam, and the hot air in the dryer is counter-contacted and supported by the nozzle A known method such as a method of spraying on the body may be used.

In addition, as a base material here, it is the flexible printed wiring base material by which the circuit was formed previously.
In addition to the desired effect, a further layer may be provided between the resin layer 3 and the resin layer 4 in order to obtain another effect.

  In the present invention, the resin layer 3 is preferably thicker than the resin layer 4 from the viewpoint of followability to a copper circuit. Moreover, the laminated structure of the present invention can be used for at least one of a bent portion and a non-bent portion of the flexible printed wiring board because of its characteristics. And at least one of the interlayer insulating materials.

[Light irradiation process]
The light irradiation step is a step of activating the photobase generator contained in the thermosetting resin composition by light irradiation in a negative pattern to cure the light irradiation portion. In the light irradiation step, the base generated in the light irradiation portion destabilizes the photobase generator, and the base is chemically proliferated, so that the resin layer can be sufficiently hardened.

  As the light irradiator used for light irradiation, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser using CAD data from a computer), a light irradiator equipped with a metal halide lamp, and an (ultra) high pressure mercury lamp It is possible to use an on-board light irradiation machine, a light irradiation machine equipped with a mercury short arc lamp, or a direct drawing apparatus using an ultraviolet lamp such as a (super) high pressure mercury lamp. The patterned light irradiation mask is a negative mask.

As the active energy ray, it is preferable to use laser light or scattered light having a maximum wavelength in the range of 350 to 410 nm. By setting the maximum wavelength within this range, the photobase generator can be activated efficiently. If a laser beam in this range is used, either a gas laser or a solid laser may be used. Moreover, the light irradiation amount varies depending on the film thickness, etc., generally 100~1500mJ / cm ^2, preferably be in the range of 300~1500mJ / cm ^2.

[Heating process]
In the heating step, the light irradiation part is cured by heating. The heating process can be cured to a deep part by the base generated in the light irradiation process. This process is a so-called PEB (POST EXPOSURE BAKE) process.
The heating temperature is preferably a temperature at which the light-irradiated portion of the thermosetting resin composition is thermally cured, but the non-irradiated portion is not thermally cured.
For example, the heating step is a temperature lower than the heat generation start temperature or the heat generation peak temperature of the unirradiated thermosetting resin composition and higher than the heat generation start temperature or the heat generation peak temperature of the light irradiated thermosetting resin composition. It is preferable to heat with. By heating in this way, only the light irradiation part can be selectively cured.

Here, the heating temperature is, for example, 80 to 140 ° C. By setting the heating temperature to 80 ° C. or higher, the light irradiation part can be sufficiently cured. On the other hand, by setting the heating temperature to 140 ° C. or lower, only the light irradiation part can be selectively cured. The heating time is, for example, 10 to 100 minutes. The heating method is the same as the drying method.
In the unirradiated portion, no base is generated from the photobase generator, so that thermosetting is suppressed.

[Development process]
In the development step, the unirradiated portion is removed by alkali development to form a negative pattern layer.
As a developing method, a known method such as a dipping method, a shower method, a spray method, or a brush method can be used. Developers include potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines such as ethanolamine, and alkali such as tetramethylammonium hydroxide aqueous solution (TMAH). An aqueous solution or a mixed solution thereof can be used.

[Second light irradiation step]
It is preferable that an ultraviolet irradiation second light irradiation step is further included after the development step.
In the second light irradiation step, the photobase generator remaining without being activated in the pattern layer of the light irradiation step is activated to generate a base.
The wavelength of ultraviolet rays and the light irradiation amount (exposure amount) in the second light irradiation step may be the same as or different from those in the step (B). The light irradiation amount (exposure amount) is, for example, 150 to 2000 mJ / cm ² .

[Thermosetting process]
It is preferable to further include a thermosetting (post-cure) thermosetting step after the developing step.
When performing both a 2nd light irradiation process and a thermosetting process after a image development process, it is preferable to perform a thermosetting process after a 2nd light irradiation process.
In this thermosetting step, the pattern layer is sufficiently thermoset by the light irradiation step or the base generated from the photobase generator in the light irradiation step and the second light irradiation step. Since the unirradiated part has already been removed at the time of the thermosetting process, the thermosetting process can be performed at a temperature equal to or higher than the curing reaction start temperature of the unirradiated thermosetting resin composition. Thereby, a pattern layer can fully be thermosetted. The heating temperature is, for example, 150 ° C. or higher.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not restrict | limited by these Examples and a comparative example.

(Examples 1 and 2 and Comparative Example 1)
Synthesis example: <Synthesis of imide ring / carboxyl group-containing resin>
In a separable three-necked flask equipped with a stirrer, nitrogen inlet tube, fractional ring, and cooling ring, 12.2 g of 3,5-diaminobenzoic acid, 2,2′-bis [4- (4-aminophenoxy) Phenyl] propane 8.2 g, NMP 30 g, γ-butyrolactone 30 g, 4,4′-oxydiphthalic anhydride 27.9 g, trimellitic anhydride 3.8 g were added at room temperature under a nitrogen atmosphere at 100 rpm. Stir for 4 hours. Next, 20 g of toluene was added and stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ° C. and 150 rpm to obtain a polyimide solution.
<Preparation of resin composition constituting each resin layer>
In accordance with the formulation shown in Table 1 below, the materials described in Examples and Comparative Examples were respectively blended, premixed with a stirrer, and then kneaded with a three-roll mill to prepare resin compositions constituting each resin layer. . The values in the table are parts by mass unless otherwise specified.

<Formation of resin layer (A)>
A flexible printed wiring board on which a circuit with a copper thickness of 18 μm was formed was prepared, and pretreated using MEC CZ-8100. Thereafter, the pre-treated flexible printed wiring board was coated with the resin compositions of Examples 1 and 2 and Comparative Example 1 by a coating method shown in Table 1 so that the film thickness would be 25 μm after drying. Went. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the resin layer (A) which consists of a resin composition.

<Formation of resin layer (B)>
On the resin layer (A) formed as described above, the resin compositions of Examples 1 and 2 were coated by the coating method shown in Table 1 so as to be 10 μm after drying. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the resin layer (B) which consists of a resin composition. In Comparative Example 1, the resin layer (B) was not formed.

<Developability (patterning) and evaluation of curing characteristics>
The base material provided with the resin layer obtained above was irradiated with a negative pattern with an exposure amount shown in Table 1 by ORC HMW680GW (metal halide lamp, scattered light). Next, heat treatment was performed at 90 ° C. for 60 minutes. Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C. and developed for 3 minutes to evaluate the developability. The obtained results are shown in Table 1.

  Next, heat treatment was performed at 150 ° C./60 minutes using a hot air circulation drying oven to obtain a patterned cured coating film. An MIT test (R = 0.38 mm / Upilex 12.5 μm base material used) and a surface hardness test (pencil hardness test) were conducted on the obtained cured coating film, and the flexibility and surface Hardness was evaluated. The obtained results are shown in Table 1 below.

＊１酸価８６ｍｇＫＯＨ／ｇ Ｍｗ：１００００
＊２ビスフェノールＡ型エポキシ樹脂(分子量：３８０）（三菱化学(株)製）
＊３オキシム型光重合開始剤（ＢＡＳＦ社製）
＊４ビスフェノールＦ型エポキシアクリレート（日本化薬(株)製）
＊５トリメチロールプロパンＥＯ変性トリアクリレート（東亞合成(株)製）
＊６ビスフェノールＡ型エポキシ樹脂(分子量：９００）（三菱化学(株)製）
＊７ビスフェノールＡ型エポキシ樹脂(分子量：５００）（三菱化学(株)製）
＊８アシルフォスフィンオキサイド系光重合開始剤 (ＢＡＳＦ社製)

* 1 Acid value 86 mg KOH / g Mw: 10,000
* 2 Bisphenol A type epoxy resin (Molecular weight: 380) (Mitsubishi Chemical Corporation)
* 3 Oxime-type photopolymerization initiator (BASF)
* 4 Bisphenol F epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd.)
* 5 Trimethylolpropane EO-modified triacrylate (manufactured by Toagosei Co., Ltd.)
* 6 Bisphenol A epoxy resin (Molecular weight: 900) (Mitsubishi Chemical Corporation)
* 7 Bisphenol A type epoxy resin (Molecular weight: 500) (Mitsubishi Chemical Corporation)
* 8 Acylphosphine oxide photopolymerization initiator (BASF)

  As is clear from the evaluation results shown in Table 1, the flexible printed wiring boards of Examples 1 and 2 can be developed in the same manner as the flexible printed wiring board of Comparative Example 1, and the flexibility and surface hardness are greatly increased. It turns out that it is excellent.

DESCRIPTION OF SYMBOLS 1 Flexible printed wiring board 2 Copper circuit 3 Resin layer 4 Resin layer 5 Mask

Claims (6)

A resin layer (A) comprising an alkali-developable resin composition not containing an alkali-soluble polyimide ;
A resin layer (B) laminated on the flexible printed wiring board via the resin layer (A);
A laminated structure comprising:
The said resin layer (B) consists of a photosensitive thermosetting resin composition containing the alkali-soluble resin which has an imide ring, a photobase generator, and a thermoreactive compound, The laminated structure characterized by the above-mentioned.   The laminated structure according to claim 1, wherein both the resin layer (A) and the resin layer (B) can be patterned by light irradiation.   The laminated structure according to claim 1 or 2, which is used for at least one of a bent portion and a non-bent portion of the flexible printed wiring board.   The laminated structure according to any one of claims 1 to 3, which is used as at least one of a cover lay, a solder resist, and an interlayer insulating material of a flexible printed wiring board.   A dry film, wherein at least one surface of the laminated structure according to any one of claims 1 to 4 is supported or protected by a film.   It has an insulating film of the hardened | cured material of the laminated structure as described in any one of Claims 1-4 on a flexible printed wiring board, The flexible printed wiring board characterized by the above-mentioned.

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