JPWO2017057431A1 - Curable resin composition, dry film, and printed wiring board using the same - Google Patents

Abstract

A curable resin composition capable of obtaining a cured product in which insulation reliability such as ion migration resistance and flame retardancy are highly compatible, a dry film having a resin layer obtained from the composition, the composition, or the A cured product of a dry film and a printed wiring board having the cured product are provided.
A curable resin composition containing a carboxyl group-containing resin, a thermosetting component, a flame retardant, and an ion scavenger, the ion scavenger being a hydrotalcite-based ion scavenger and a non-hydrotalcite-based ion scavenger It is a curable resin composition characterized by being a mixture of these.

Description

  The present invention relates to a curable resin composition, a dry film, and a printed wiring board using the same.

  Curable resin compositions are widely used as solder resists for printed wiring boards such as flexible printed wiring boards (hereinafter abbreviated as FPC). This solder resist is used for the purpose of protecting the surface layer circuit of the printed wiring board, and insulation reliability is required. In particular, recently, the density of printed wiring boards has been remarkably increased, and the circuit has a minimum L (line) / S (space) of 10 μm / 10 μm, and higher insulation reliability is required than before. In particular, in FPC applications, in order to attach an electromagnetic wave shield on an insulating film such as a coverlay, in addition to the resistance to ion migration between circuits (XY direction), between the circuit and the electromagnetic wave shield via a solder resist. Interlayer (Z-axis direction) ion migration resistance is also required, and higher insulation reliability, particularly ion migration resistance is required.

  On the other hand, conventionally, for example, as a means for improving the insulation reliability of a printed wiring board, in particular, ion migration resistance, a technique of blending a layered double hydroxide such as hydrotalcite with a photosensitive resin composition has been proposed ( Patent Document 1).

  On the other hand, the solder resist is required to have flame retardancy because the printed wiring board is mounted on an electronic device. Among them, unlike the rigid type printed wiring board solder resist formed on the glass epoxy substrate, the FPC solder resist is usually formed on a polyimide substrate, and therefore, higher flame resistance is required.

JP 2010-237270 A

Thus, the curable resin composition used for the solder resist particularly for FPC applications is required to have excellent flame retardance in addition to insulation reliability such as ion migration resistance. It was a fact that it was difficult.
Accordingly, an object of the present invention is to provide a curable resin composition capable of obtaining a cured product having both high insulation reliability such as ion migration resistance and flame retardancy, and a dry layer having a resin layer obtained from the composition. It is providing the cured product of the resin layer of a film, this composition, or this dry film, and the printed wiring board which has this cured product.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have studied to add a hydrotalcite-based ion scavenger to improve insulation reliability, particularly ion migration resistance. It was noticed that the compounding of the system ion scavenger improves the insulation reliability such as ion migration resistance, but lowers the flame retardance. Therefore, as a result of further investigation, by using a mixture of hydrotalcite-based ion scavengers and non-hydrotalcite-based ion scavengers, resistance to ion migration, etc., without surprisingly reducing flame retardancy, etc. As a result, it was found that the insulation reliability can be improved, and the present invention has been completed.

  That is, the curable resin composition of the present invention is a curable resin composition containing a carboxyl group-containing resin, a thermosetting component, a flame retardant, and an ion scavenger, and the ion scavenger is a hydrotalcite ion. It is a mixture of a scavenger and an ion scavenger other than hydrotalcite.

  In the curable resin composition of the present invention, the blending ratio of the hydrotalcite-based ion scavenger and the non-hydrotalcite-based ion scavenger is preferably in the range of 100: 10 to 100: 500 on a mass basis. It is. The curable resin composition of the present invention preferably contains at least one of a photopolymerization initiator and a compound having an ethylenically unsaturated group. Furthermore, the curable resin composition of the present invention is preferably a photosensitive resin composition containing a photopolymerization initiator. Furthermore, the thermosetting component is preferably a cyclic (thio) ether compound. Moreover, the curable resin composition of this invention can be used suitably in order to form at least any one of a coverlay and a soldering resist.

  In addition, the dry film of the present invention is characterized by having a resin layer formed by applying and drying the curable resin composition on the film.

  Furthermore, the cured product of the present invention is obtained by curing the curable resin composition or the resin layer of the dry film.

  Furthermore, the printed wiring board of the present invention comprises the cured product.

ADVANTAGE OF THE INVENTION According to this invention, the curable resin composition which can obtain the hardened | cured material which made highly compatible insulation reliability, such as ion migration tolerance, and a flame retardance, The dry film which has a resin layer obtained from this composition Further, a cured product of the resin layer of the composition or the dry film, and a printed wiring board having the cured product can be provided.
The curable resin composition of the present invention can be suitably used for forming at least one of an FPC coverlay and a solder resist. The curable resin composition of the present invention is also suitable as a resin composition for an adhesive layer of a cover lay having a multilayer structure. Here, the adhesive layer refers to a resin layer in contact with the FPC of a cover lay having a laminated structure of two or more layers.

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

The curable resin composition of the present invention (hereinafter also simply referred to as “resin composition”) includes a carboxyl group-containing resin, a thermosetting component, a flame retardant, and an ion scavenger. Particularly in the present invention, it is essential that the ion scavenger is a mixture of a hydrotalcite-based ion scavenger and an ion scavenger other than the hydrotalcite-based, and by using these ion scavengers, Insulation reliability such as ion migration resistance and flame retardancy can be achieved at a high level.
Hereinafter, each component will be described in detail.

[Carboxyl group-containing resin]
As the carboxyl group-containing resin contained in the resin composition of the present invention, a known and commonly used resin compound containing a carboxyl group in the molecule can be used. Due to the presence of the carboxyl group, the resin composition can be made alkali developable. Further, from the viewpoint of making the resin composition of the present invention photocurable and developing resistance, it is preferable to have an ethylenically unsaturated bond in the molecule in addition to the carboxyl group. Only a carboxyl group-containing resin having no bond can also be used. When the carboxyl group-containing resin does not have an ethylenically unsaturated bond, a compound (photopolymerizable compound) having one or more ethylenically unsaturated groups in the molecule is used to make the composition photocurable. Must be used together. As the ethylenically unsaturated double bond, those derived from acrylic acid, methacrylic acid or derivatives thereof are preferable.

  Specific examples of the carboxyl group-containing resin that can be used in the resin composition of the present invention include the compounds listed below (any of oligomers and polymers).

  (1) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth) acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene.

  (2) Diisocyanate compounds such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, carboxyl-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, and polyethers -Based polyol, polyester-based polyol, polyolefin-based polyol, acrylic polyol, bisphenol A-based alkylene oxide adduct diol, carboxyl group-containing urethane resin by polyaddition reaction of diol compounds such as compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups .

  (3) Diisocyanate compounds such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A systems A terminal carboxyl group-containing urethane resin obtained by reacting an acid anhydride with a terminal of a urethane resin by a polyaddition reaction of a diol compound such as an alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

  (4) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( Photosensitive carboxyl group-containing urethane resin by polyaddition reaction of (meth) acrylate or its modified partial anhydride, carboxyl group-containing dialcohol compound and diol compound.

  (5) During the synthesis of the resin of the above (2) or (4), a compound having one hydroxyl group and one or more (meth) acryloyl groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and the terminal ( (Meth) acrylic carboxyl group-containing urethane resin.

  (6) During the synthesis of the resin of (2) or (4) above, one isocyanate group and one or more (meth) acryloyl groups are introduced into the molecule, such as a molar reaction product such as isophorone diisocyanate and pentaerythritol triacrylate. The carboxyl group-containing urethane resin which added the compound which has and was terminally (meth) acrylated.

  (7) A photosensitive carboxyl group-containing resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth) acrylic acid and adding a dibasic acid anhydride to a hydroxyl group present in the side chain.

  (8) Photosensitivity in which (meth) acrylic acid is reacted with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin, and a dibasic acid anhydride is added to the resulting hydroxyl group. Functional carboxyl group-containing resin.

  (9) A carboxyl group-containing polyester resin obtained by reacting a polyfunctional oxetane resin with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl group.

  (10) Unsaturation in the reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and / or a cyclic carbonate compound such as ethylene carbonate or propylene carbonate. A carboxyl group-containing photosensitive resin obtained by partial esterification with a group-containing monocarboxylic acid and reacting the resulting reaction product with a polybasic acid anhydride.

  (11) A polybasic reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and / or a cyclic carbonate compound such as ethylene carbonate or propylene carbonate. A carboxyl group-containing resin obtained by reacting an acid anhydride.

  (12) The resin of the above (1) to (11) further has one epoxy group and one or more (meth) acryloyl groups in the molecule such as glycidyl (meth) acrylate and α-methylglycidyl (meth) acrylate. Photosensitive carboxyl group-containing resin obtained by adding a compound.

  In addition, in this specification, (meth) acrylate is a term which generically refers to acrylate, methacrylate and a mixture thereof, and the same applies to other similar expressions.

Since the carboxyl group-containing resin as described above has a large number of carboxyl groups in the side chain of the backbone polymer, development with an alkaline aqueous solution becomes possible.
Moreover, the acid value of the said carboxyl group-containing resin has the preferable range of 20-200 mgKOH / g, More preferably, it is the range of 40-150 mgKOH / g. When the acid value of the carboxyl group-containing resin is within the above range, the alkali solubility is good and patterning by alkali development becomes easy.

  Moreover, although the weight average molecular weight of carboxyl group-containing resin changes with resin frame | skeletons, 1,000-100,000 are preferable and 3,000-50,000 are more preferable. When the molecular weight is within the above range, the alkali solubility is good and patterning by alkali development becomes easy.

[Thermosetting component]
The thermosetting component has a functional group capable of addition reaction with a carboxyl group by heat. As the thermosetting component, for example, a compound having a cyclic (thio) ether group is preferable, and examples thereof include an epoxy resin and a polyfunctional oxetane compound.

  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. Note that a hydrogenated epoxy resin may be used.

  Specifically, bisphenol A type epoxy resin, brominated epoxy resin, novolak type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy Resin, trihydroxyphenylmethane type epoxy resin, bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin, bisphenol A novolac 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 methacrylate copolymer System epoxy resins, copolymerized epoxy resins of cyclohexylmaleimide and glycidyl methacrylate, and a CTBN modified epoxy resin.

  In addition, you may mix | blend well-known and usual compounds, such as a maleimide compound, a block isocyanate compound, an amino resin, a benzoxazine resin, a carbodiimide resin, a cyclocarbonate compound, an episulfide resin, as a thermosetting component.

  Such a thermosetting component may be used individually by 1 type, and may use 2 or more types together. As a compounding quantity of a thermosetting component, it is preferable that equivalent ratio (carboxyl group: thermoreactive groups, such as an epoxy group) with the said carboxyl group-containing resin is 1: 0.1 to 1:10. 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.

[Flame retardants]
As the flame retardant constituting the resin composition of the present invention, a known and commonly used flame retardant can be used. Examples of flame retardants include phosphoric acid esters and condensed phosphoric acid esters, phosphorus element-containing (meth) acrylates, phosphorus-containing compounds having phenolic hydroxyl groups, cyclic phosphazene compounds, phosphazene oligomers, phosphorus-containing compounds such as phosphinic acid metal salts, trioxide Examples thereof include antimony compounds such as antimony and antimony pentoxide, halides such as pentabromodiphenyl ether and octabromodiphenyl ether, and layered double hydroxides such as metal hydroxides such as aluminum hydroxide and magnesium hydroxide. The said flame retardant may be used individually by 1 type, and may use 2 or more types together.

式中、Ｍ^２＋は２価の金属陽イオン、Ｍ^３＋は３価の金属陽イオン、Ａ^ｎ−はｎ価の陰イオンを表し、各元素および原子団の下付き添字は各元素および原子団の比率を表し、Ｘは０＜Ｘ≦０．３３である。ｍは０≧であるが、脱水により大きく変わる。[Ion scavenger]
The ion scavenger contained in the resin composition of the present invention is a mixture of a hydrotalcite-based ion scavenger and an ion scavenger other than the hydrotalcite-based agent.
As the hydrotalcite-based ion scavenger contained in the resin composition of the present invention, hydrotalcite and hydrotalcite-like compounds can be suitably used. The hydrotalcite and the hydrotalcite-like compound include, for example, a positively charged basic layer [Mg _1-X Al _X (OH) ₂ ] ^{X +} and a negatively charged intermediate layer [(CO ₃ ) _{X / 2} · mH _2. O] A layered inorganic compound composed of ^X- . Many divalent and trivalent metals have the same layered structure, and the general structural formula is represented by the following formula (I).

Wherein, M ²⁺ is a divalent metal cation, M ³⁺ is a trivalent metal cation, A ^n-represents an n-valent anion, subscripts of the elements and atomic groups are the elements and atomic groups X represents 0 <X ≦ 0.33. m is 0 ≧, but changes greatly with dehydration.

Specific examples of hydrotalcite and hydrotalcite-like compounds include Indigirite Mg ₂ Al ₂ [(CO ₃ ) ₄ (OH) ₂ ] .15H ₂ O, Fe ²⁺ ₄ Al ₂ [(OH) ₁₂ CO ₃ ]. 3H ₂ O, Quintinite Mg ₄ Al ₂ (OH) ₁₂ CO ₃ · H ₂ O, Manasseite Mg ₆ Al ₂ [(OH) ₁₆ CO ₃ ] · 4H ₂ O, SjOegrenite Mg ₆ Fe ³⁺ ₂ [(OH) ₁₆ CO _{3] · 4H 2 O, Zaccagnaite} Zn 4 Al 2 (CO 3) (OH) 12 · 3H 2 O, Desautelsite Mg 6 Mn 3+ 2 [(OH) 16 CO 3] · 4H 2 O, hydrotalcite Mg 6 Al 2 [ (OH) ₁₆ CO ₃ ] · 4H ₂ O, Pyroaurite Mg ₆ Fe ^{3 +} ₂ [(OH) ₁₆ CO ₃ ] · 4H ₂ O, Reevesite Ni ₆ Fe ³⁺ ₂ [(OH) ₁₆ C O ₃ ] · 4H ₂ O, Stichtite Mg ₆ Cr ₂ [(OH) ₁₆ CO ₃ ] · 4H ₂ O, Takovite Ni ₆ Al ₂ [(OH) ₁₆ CO ₃ ] · 4H ₂ O, and the like.

Moreover, as a commercial item, Kyowa Chemical Industry Co., Ltd. product; Alkamizer, DHT-4A, Kyoward 500, Kyoward 1000, Sakai Chemical Co., Ltd. STABIACE series HT-1, HT-7, HT-P And synthetic hydrotalcite-like compounds.
These hydrotalcite-based ion scavengers may be used alone or in combination of two or more.

As the ion scavenger other than the hydrotalcite-based agent contained in the resin composition of the present invention, a publicly known ion scavenger can be used. As an ion scavenger other than this hydrotalcite, any of a cation exchange type, an anion exchange type, and a both ion exchange type can be used.
Specific examples include inorganic particles composed of Zr-based compounds, inorganic particles composed of Sb-based compounds, and inorganic particles composed of Bi-based materials. In addition, inorganic particles composed of binary systems of Sb compounds and Bi compounds, inorganic particles composed of binary systems of Mg compounds and Al compounds, inorganic particles composed of binary systems of Zr compounds and Bi compounds, Examples thereof include inorganic particles composed of a ternary system of a Zr-based compound, a Mg-based compound, and an Al-based compound. Among these, from the viewpoint of not reducing the effect of the flame retardant, inorganic particles comprising a Zr compound, inorganic particles comprising a binary system of Zr compound and Bi compound, ternary of Zr compound, Mg compound and Al compound. Inorganic particles comprising the system are preferred.
Commercially available ion supplements other than this hydrotalcite are IXE-100, IXE-300, IXE-500, IXE-550, IXE-800, IXE-600, IXE- manufactured by Toa Gosei Co., Ltd. 6107, IXE-6136, IXEPLAS-A1, IXEPLAS-B1, and the like.
These ion scavengers other than hydrotalcite may be used alone or in combination of two or more.

In the present invention, it is essential that the ion scavenger is a mixture of a hydrotalcite ion scavenger and a non-hydrotalcite ion scavenger. By using these ion scavengers, both insulation reliability such as ion migration resistance and flame retardancy can be achieved at a high level. This is considered to be due to the following reasons. When a hydrotalcite-based ion scavenger is added to improve insulation reliability, especially ion migration resistance, the flame retardancy will decrease, but the amount of hydrotalcite-based will not decrease flame retardancy. When an ion scavenger is blended, ion migration resistance becomes insufficient. Therefore, it is considered that when the ion scavenger other than the hydrotalcite system having flame retardancy is used in combination, the insufficient ion migration resistance can be compensated while maintaining the flame retardancy. Therefore, according to the present invention, insulation reliability, in particular, ion migration resistance and flame retardancy can be made highly compatible.
The blending ratio of the hydrotalcite-based ion scavenger and the ion scavenger other than the hydrotalcite-based material is in the range of 100: 10 to 100: 500, preferably in the range of 100: 50 to 100: 400 on a mass basis. More preferably, it is in the range of 100: 100 to 100: 400. Moreover, the total compounding quantity of an ion trapping agent is 1-50 mass% with respect to the whole resin composition in conversion of solid content, Preferably it is 2-40 mass%, More preferably, it is 2-20 mass%.

  The resin composition of the present invention can further contain at least one of a photopolymerization initiator and a compound having an ethylenically unsaturated group.

(Photopolymerization initiator)
As the photopolymerization initiator, known ones can be used, and examples thereof include benzoin compounds, acylphosphine oxide compounds, acetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, and thioxanthone compounds.
In particular, when used in a PEB step after light irradiation described later, a photopolymerization initiator that also has a function as a photobase generator is suitable. In this PEB step, a photopolymerization initiator and a photobase generator may be used in combination.

A photopolymerization initiator that also functions as a photobase generator is a catalyst for the addition reaction of a thermosetting component, 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. Is a compound that produces one or more basic substances that can function as Examples of basic substances include secondary amines and tertiary amines.
Examples of the photopolymerization initiator having a function as a photobase generator include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, and N-acylated aromatics. And compounds having a substituent such as a group amino group, a nitrobenzyl carbamate group, and an alkoxybenzyl carbamate group. Among these, an oxime ester compound and an α-aminoacetophenone compound are preferable, and an oxime ester compound is more preferable. As the α-aminoacetophenone compound, those having two or more nitrogen atoms are particularly preferable.

  The α-aminoacetophenone compound is not particularly limited as long as it has a benzoin ether bond in the molecule and is cleaved within the molecule when irradiated with light 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 (trade name: Irgacure 369, manufactured by BASF Japan) and 4- (methylthiobenzoyl) -1-methyl. -1-morpholinoethane (trade name: Irgacure 907, manufactured by BASF Japan), 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl]- Commercially available compounds such as 1-butanone (trade name: Irgacure 379, 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 the oxime ester compound include CGI-325, Irgacure OXE01, Irgacure OXE02 manufactured by BASF Japan, N-1919, and NCI-831 manufactured by Adeka. Further, compounds having two oxime ester groups in the molecule described in Japanese Patent No. 4,344,400 can also be suitably used.

  Such a photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type. The compounding quantity of the photoinitiator in a resin composition is 0.1-30 mass parts with respect to 100 mass parts of carboxyl group-containing resin in conversion of solid content, Preferably it is 0.5-20 mass parts. When it is in the range of 0.1 to 30 parts by mass, the curing balance between the coating film surface and the deep part is improved, and the sensitivity, resolution, and the like can be improved. In addition, photocurability is improved, and coating properties such as insulation reliability and chemical resistance can be improved. However, when using as a resin composition for the adhesive layer of a cover layer having a two-layer structure, a configuration not containing a photopolymerization initiator is preferred.

(Compound having an ethylenically unsaturated group)
A compound having an ethylenically unsaturated group (hereinafter also referred to as a photopolymerizable compound) is a compound having one or more ethylenically unsaturated groups in the molecule. The photopolymerizable compound assists the polymerization reaction of ethylenically unsaturated groups by irradiation with active energy rays. As the ethylenically unsaturated group, those derived from (meth) acrylate are preferable.

  Examples of the photopolymerizable compound include conventionally known polyester (meth) acrylate, polyether (meth) acrylate, urethane (meth) acrylate, carbonate (meth) acrylate, and epoxy (meth) acrylate. Specifically, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; N, N-dimethylacrylamide Acrylamides such as N-methylol acrylamide and N, N-dimethylaminopropyl acrylamide; aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate and N, N-dimethylaminopropyl acrylate; hexanediol, trimethylolpropane, Polyhydric alcohols such as pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate or the like Multifunctional acrylates such as tylene oxide adduct, propylene oxide adduct, or ε-caprolactone adduct; phenoxyacrylate, bisphenol A diacrylate, and polyfunctional such as ethylene oxide adduct or propylene oxide adduct of these phenols Acrylates; glyceryl diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyfunctional acrylates of glycidyl ether such as triglycidyl isocyanurate; not limited to the above, polyether polyol, polycarbonate diol, hydroxyl-terminated polybutadiene, Polyols such as polyester polyols can be directly acrylated or urethane acrylate via diisocyanate. Examples include acrylated acrylates and melamine acrylates, and at least one of each methacrylate corresponding to the acrylate.

  Furthermore, you may use the epoxy acrylate resin etc. which made acrylic acid react with polyfunctional epoxy resins, such as a cresol novolak-type epoxy resin, as a photopolymerizable compound. Such an epoxy acrylate resin can improve photocurability without deteriorating the touch drying property.

  The blending amount of the photopolymerizable compound is 1 to 50 parts by mass, more preferably 3 to 30 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin in terms of solid content. When the blending amount is in the range of 1 to 50 parts by mass, photocurability and tackiness can be improved.

(Polymer resin)
The resin composition of the present invention can be blended with conventionally known polymer resins for the purpose of improving the flexibility and dryness of the touch of the resulting cured product. Examples of the polymer resin include cellulose, polyester, phenoxy resin, polyvinyl acetal, polyvinyl butyral, polyamide, polyamideimide binder polymer, block copolymer, elastomer and the like. The above polymer resins may be used alone or in combination of two or more.

(Inorganic filler)
An inorganic filler can be blended in the resin composition of the present invention. The inorganic filler is used for suppressing the curing shrinkage of the cured product of the resin composition and improving properties such as adhesion and hardness. Examples of 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, and Neuburg. Can be mentioned. The said inorganic filler may be used individually by 1 type, and may use 2 or more types together.

(Coloring agent)
A coloring agent can be mix | blended with the resin composition of this invention. As the colorant, conventionally known colorants such as red, blue, green, yellow, white, and black can be used, and any of pigments, dyes, and pigments may be used.

(Organic solvent)
In the resin composition of the present invention, an organic solvent can be used for preparing the resin composition or adjusting the viscosity for application to a substrate or a carrier film.
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)
If necessary, the resin composition of the present invention may further contain components such as a mercapto compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber. As these, those known in the field of electronic materials can be used. Further, the above resin composition includes known and commonly used thickeners such as finely divided silica, organic bentonite and montmorillonite, silicone-based, fluorine-based and polymer-based antifoaming agents and / or leveling agents, and silane coupling agents. In addition, known and commonly used additives such as a rust inhibitor can be blended.

[Dry film]
The dry film of the present invention has a resin layer made of the resin composition of the present invention. The multilayer film may be a dry film having a layer made of a resin composition other than the resin composition of the present invention.
In forming a dry film, for example, the resin composition of the present invention is diluted with an organic solvent to have an appropriate viscosity, and is applied to a carrier film with a uniform thickness by a known technique such as a comma coater. Thereafter, drying is usually performed at a temperature of 50 to 130 ° C. for 1 to 30 minutes to form a resin layer on the carrier film.

  A plastic film is used as the carrier film. Although there is no restriction | limiting in particular about the thickness of a carrier film, Generally, it selects suitably in the range of 10-150 micrometers. After forming the resin layer on the carrier film, a peelable cover film may be further laminated on the surface of the resin layer.

  The resin composition or dry film of the present invention as described above can be used for a resin insulating layer of a printed wiring board, for example, a coverlay or a solder resist. The resin composition of the present invention can also be used as a resin composition for an adhesive layer, which is a resin layer in contact with a printed wiring board, of a coverlay having a laminated structure of two or more layers.

  The cover lay (laminated structure) having a laminated structure of two or more layers includes an adhesive layer that is a resin layer in contact with the printed wiring board, and a protective layer that is a resin layer that can be patterned by light irradiation on the upper layer. It is preferable that it is comprised. By using the resin composition of the present invention as an adhesive layer of this laminated structure, a laminated structure such as a coverlay composed of an adhesive layer and a protective layer can be formed in a batch by development, and Insulation reliability such as ion migration resistance and flame retardancy can be achieved at a high level.

  Here, the resin composition constituting the protective layer contains a carboxyl group-containing resin (alkali-soluble resin), a photopolymerization initiator, and a thermosetting component, and disclosed in JP-A-2015-155199. The described compositions and the like can be used. As the carboxyl group-containing resin (alkali-soluble resin), a carboxyl group-containing resin (alkali-soluble resin) having an imide ring or an imide precursor skeleton is preferable.

[Method of manufacturing printed wiring board]
Next, an example of a method for producing a printed wiring board from the resin composition of the present invention will be described with reference to the process diagrams of FIGS. 1 and 2 show the case where the resin layer has a laminated structure, it may be composed of only one layer.

  The manufacturing method of the printed wiring board shown in the process diagram of FIG. 1 includes a step of forming a layer of a laminated structure on a printed wiring board on which a conductor circuit is formed (lamination step), and an active energy ray is applied to the layer of the laminated structure. It is a manufacturing method including a pattern irradiation step (exposure step) and a step (development step) in which a layer of the laminated structure is collectively formed by alkali development of the layer of the laminated structure. Further, if necessary, after the alkali development, further photocuring or heat curing (post-cure process) can be performed to completely cure the layer of the laminated structure, thereby obtaining a highly reliable printed wiring board.

  The manufacturing method of the printed wiring board shown in the process diagram of FIG. 2 includes a step of forming a layer of the laminated structure on the printed wiring board on which the conductor circuit is formed (lamination step), and an active energy ray is applied to the layer of the laminated structure. A pattern irradiation process (exposure process), a process of heating the layer of the multilayer structure (post exposure bake (PEB) process), and a layer of the multilayer structure were alkali-developed and patterned. It is a manufacturing method including the process (development process) which forms the layer of a laminated structure. Further, if necessary, after the alkali development, further photocuring or heat curing (post-cure process) can be performed to completely cure the layer of the laminated structure, thereby obtaining a highly reliable printed wiring board. In particular, when an imide ring-containing alkali-soluble resin is used in the resin layer 4 (protective layer), it is preferable to use the procedure shown in the process diagram of FIG.

Hereafter, each process shown in FIG. 1 or FIG. 2 is demonstrated in detail.
[Lamination process]
In this step, a resin layer 3 (adhesive layer) made of a resin composition and a resin layer 4 (protective layer) made of a resin composition on the resin layer 3 are formed on the printed wiring board 1 on which the conductor circuit 2 is formed. Are formed. Here, each resin layer constituting the laminated structure forms, for example, the resin layers 3 and 4 by sequentially applying and drying the resin composition constituting the resin layers 3 and 4 on the printed wiring board 1. Alternatively, it may be formed by laminating the resin composition constituting the resin layers 3 and 4 in the form of a dry film having a two-layer structure on the printed wiring board 1.
This resin layer is preferably made of an alkali development type photosensitive resin composition. As the alkali developing photosensitive resin composition, a known resin composition can be used. For example, a known resin composition for a coverlay or a solder resist can be used. Thus, by setting the resin layer to a laminated structure instead of a single layer, a cured product having further excellent impact resistance and flexibility can be obtained.

The application method of the resin composition to the wiring board 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 the case of the laminating method, first, the resin composition is diluted with an organic solvent, adjusted to an appropriate viscosity, applied onto a carrier film and dried to prepare a dry film having a resin layer. Next, after laminating the resin layer with a laminator or the like so as to come into contact with the wiring substrate, a known method of peeling the carrier film can be used.

[Exposure process]
In this step, the photopolymerization initiator contained in the resin layer 4 is activated into a negative pattern by irradiation with active energy rays, and the exposed portion is cured. As the exposure machine, a direct drawing apparatus, an exposure machine equipped with a metal halide lamp, or the like can be used. The patterned exposure mask is a negative mask.

As the active energy ray used for exposure, it is preferable to use laser light or scattered light having a maximum wavelength in the range of 350 to 450 nm. By setting the maximum wavelength within this range, the photopolymerization initiator can be activated efficiently. Moreover, although the exposure amount changes with film thickness etc., it can usually be set to 100-1500 mJ / cm < ² >.

[PEB process]
In this step, after exposure, the exposed portion is cured by heating the resin layer. By this step, a photopolymerization initiator having a function as a photobase generator is used, or by a base generated in the exposure step of the resin layer 4 composed of a composition in which a photopolymerization initiator and a photobase generator are used in combination, The resin layer can be cured to a deep part. The heating temperature is, for example, 80 to 140 ° C. The heating time is, for example, 10 to 100 minutes. Since the curing of the resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, distortion and curing shrinkage can be suppressed as compared with a case where curing proceeds by a photoradical reaction.

[Development process]
In this step, the unexposed portion is removed by alkali development to form a negative patterned insulating film, particularly a cover lay and a solder resist. The developing method can be a known method such as dipping. As the developer, sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkaline aqueous solutions such as tetramethylammonium hydroxide aqueous solution (TMAH), or a mixed solution thereof. Can be used.

[Post cure process]
In this step, after the development step, the resin layer is completely thermoset to obtain a highly reliable coating film. The heating temperature is, for example, 140 ° C to 180 ° C. The heating time is, for example, 20 to 120 minutes. Further, light irradiation may be performed before or after the post cure.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, this invention is not limited to the following Example and comparative example. In the following description, “parts” and “%” are all based on mass unless otherwise specified.

(Examples 1-14, Comparative Examples 1-6)
<Preparation of resin composition>
In accordance with the formulation described in Tables 1 to 3 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 a curable resin composition. The values in the table are parts by mass unless otherwise specified.

The prepared curable resin composition was evaluated for insulation reliability and flame retardancy. The contents of the evaluation are as follows.
<Insulation reliability>
A polyimide substrate (Espanex, manufactured by Nippon Steel Chemical Co., Ltd.) having a copper thickness of 18 μm on which a pattern of L / S = 50/50 μm was formed was subjected to surface treatment using Mecbright CB-801Y. The curable resin compositions of Examples 1-14 and Comparative Examples 1-6 were applied to the polyimide substrate by screen printing, dried at 80 ° C. for 30 minutes, and allowed to cool to room temperature. The entire surface of the obtained substrate was exposed at an exposure amount of 300 mJ / cm ² using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp, and 30 ° C. and spray pressure 0 using a 1 mass% Na ₂ CO ₃ aqueous solution. Development was performed for 60 seconds under the condition of 2 MPa. This substrate was heat-cured at 150 ° C. for 60 minutes, and then an electromagnetic shielding material was press-bonded to produce an insulating reliability evaluation substrate.
With respect to the manufactured evaluation substrate, a bias voltage of DC 50 V is applied in the Z-axis direction, and the resistance value is continuously measured in a constant temperature and humidity chamber at 85 ° C. and 85% RH to confirm whether or not a short circuit occurs, thereby preventing ion migration. Evaluated. The judgment criteria are as follows.
○: No short circuit after 1000 hours.
×: Short circuit occurred within 1000 hours.

<Flame retardance>
The entire surface of the curable resin compositions of Examples 1 to 14 and Comparative Examples 1 to 6 was applied by screen printing to a polyimide film substrate (200H, 100H manufactured by Toray DuPont Co., Ltd.) having a thickness of 50 μm and 25 μm. It dried at 80 degreeC and 15 minutes, and stood to cool to room temperature. Similarly, the entire back surface was applied and dried at 80 ° C. for 20 minutes. The entire surface of the obtained double-side coated substrate is exposed at an exposure amount of 300 mJ / cm ² using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp, and a 1% by mass Na ₂ CO ₃ aqueous solution is used. The development processing was performed for 60 seconds under the conditions of 30 ° C. and spray pressure 2 kg / cm ² . This double-sided coated substrate was heat-cured at 150 ° C. for 60 minutes to produce a flame retardant evaluation substrate.
About the produced evaluation board | substrate, the thin material perpendicular | vertical combustion test based on UL94 specification was done, and the flame retardance was evaluated. Based on the UL94 standard, the evaluation criteria were indicated as “◯” when the flame retardance was confirmed, and “X” when there was no flame retardance.

＊１：カルボキシル基含有変性エポキシアクリレート樹脂、不揮発分６５．０質量％、固形分酸価１００ｍｇＫＯＨ／ｇ（日本化薬（株）製）
＊２：ビフェニルノボラック型エポキシ樹脂（日本化薬（株）製）
＊３：フェノキシホスファゼン（大塚化学（株）製）
＊４：ホスフィン酸金属塩（クラリアント社製）
＊５：オキシムエステル系光重合開始剤（ＢＡＳＦジャパン社製）
＊６：ハイドロタルサイト化合物（協和化学工業（株）製）
＊７：無機イオン補足剤（両イオン交換型）（東亜合成（株）製）
＊８：無機イオン補足剤（両イオン交換型）（東亜合成（株）製）
＊９：無機イオン補足剤（陽イオン交換型）（東亜合成（株）製）
＊１０：無機イオン補足剤（両イオン交換型）（東亜合成（株）製）
＊１１：ビスフェノールＡ−ＥＯ変性ジアクリレート（新中村化学工業（株）製）

* 1: Carboxyl group-containing modified epoxy acrylate resin, nonvolatile content 65.0% by mass, solid content acid value 100 mgKOH / g (manufactured by Nippon Kayaku Co., Ltd.)
* 2: Biphenyl novolac epoxy resin (Nippon Kayaku Co., Ltd.)
* 3: Phenoxyphosphazene (Otsuka Chemical Co., Ltd.)
* 4: Phosphinic acid metal salt (manufactured by Clariant)
* 5: Oxime ester photopolymerization initiator (BASF Japan)
* 6: Hydrotalcite compound (Kyowa Chemical Industry Co., Ltd.)
* 7: Inorganic ion scavenger (both ion exchange type) (manufactured by Toa Gosei Co., Ltd.)
* 8: Inorganic ion scavenger (both ion exchange type) (manufactured by Toa Gosei Co., Ltd.)
* 9: Inorganic ion scavenger (cation exchange type) (manufactured by Toa Gosei Co., Ltd.)
* 10: Inorganic ion scavenger (both ion exchange type) (manufactured by Toa Gosei Co., Ltd.)
* 11: Bisphenol A-EO modified diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)

  As is clear from the results shown in Tables 1 to 3, in Examples 1 to 14, an ion scavenger other than the hydrotalcite system is used in combination with the hydrotalcite ion scavenger, and insulation reliability and flame retardancy are achieved. Both properties were good. On the other hand, in Comparative Examples 1 and 2, since the ion trapping agent was not included, the insulation reliability was lowered. In Comparative Example 3, only the hydrotalcite-based ion scavenger was used, and although the insulation reliability was obtained, the flame retardancy was lowered. Furthermore, in Comparative Examples 4-6, only ion trapping agents other than hydrotalcite were used, and the insulation reliability was lowered. As a result, in these comparative examples, insulation reliability and flame retardance could not be made highly compatible.

(Examples 15 and 16, Comparative Examples 7 and 8)
<Formation of laminated structure>
(Synthesis example 1: Synthesis example of alkali-soluble resin having imide ring)
12.2 g of 3,5-diaminobenzoic acid, 2,2′-bis [4- (4-aminophenoxy) was added to a separable three-necked flask equipped with a stirrer, a nitrogen inlet tube, a fractionation ring and a cooling ring. Phenyl] propane (8.2 g), NMP (30 g), γ-butyrolactone (30 g), 4,4′-oxydiphthalic anhydride (27.9 g) and trimellitic anhydride (3.8 g) were added. For 4 hours. Next, 20 g of toluene was added, and the mixture was stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ° C. and 150 rpm to obtain an imide ring-containing alkali-soluble resin solution. Thereafter, γ-butyrolactone was added so that the solid content was 30% by mass. The obtained resin solution had a solid content acid value of 86 mg KOH / g and Mw of 10,000.

<Adjustment of resin composition constituting each layer>
In accordance with the formulation shown in Table 4 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 form an adhesive layer and a protective layer A product was prepared. The values in the table are parts by mass unless otherwise specified.
In addition, the resin composition for adhesive layers of each laminated structure of Examples 15 and 16 and Comparative Examples 7 and 8 is different from Examples 2 and 3 and Comparative Examples 3 and 6 except that it does not contain a photopolymerization initiator. It was used as the same composition as the resin composition.

<Formation of adhesive layer>
A flexible printed wiring substrate on which a circuit having a copper thickness of 18 μm was formed was prepared, and pre-treatment was performed using CZ-8100 manufactured by MEC. Then, the resin composition for each adhesive layer was apply | coated to the flexible printed wiring base material which performed the pretreatment so that the film thickness after drying might be set to 25 micrometers. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the contact bonding layer which consists of a resin composition.

<Formation of protective layer>
On the said adhesive layer, the resin composition for each protective layer was apply | coated so that the film thickness after drying might be 10 micrometers. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the protective layer which consists of a resin composition.

  Thus, the unhardened laminated structure which consists of an adhesive layer and a protective layer which were described in Examples 15 and 16 and Comparative Examples 7 and 8 was formed on the flexible printed wiring board.

<Production of flexible printed wiring board>
First, using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp, 500 mJ / cm ² for the uncured laminated structure on each flexible printed wiring substrate on which the uncured laminated structure is formed as described above. The whole surface was exposed. Then, after performing a PEB step at 90 ° C. for 30 minutes, development (30 ° C., 0.2 MPa, 1 mass% Na ₂ CO ₃ aqueous solution) is performed in 60 seconds, and thermosetting at 150 ° C. × 60 minutes, A flexible printed wiring board on which a cured laminated structure was formed was obtained.

<Insulation reliability>
An electromagnetic wave shielding material was press-bonded to each flexible printed wiring board obtained above to produce an evaluation board for insulation reliability.
With respect to the manufactured evaluation substrate, a bias voltage of DC 50 V is applied in the Z-axis direction, and the resistance value is continuously measured in a constant temperature and humidity chamber at 85 ° C. and 85% RH to confirm whether or not a short circuit occurs, thereby preventing ion migration. Evaluated. The judgment criteria are as follows.
○: No short circuit after 1000 hours.
×: Short circuit occurred within 1000 hours.

<Flame retardance>
About each flexible printed wiring board obtained above, the thin material perpendicular | vertical combustion test based on UL94 specification was done, and the flame retardance was evaluated. Based on the UL94 standard, the evaluation criteria were indicated as “◯” when the flame retardance was confirmed, and “X” when there was no flame retardance.

<Flexibility (MIT test)>
Each flexible printed wiring board obtained above was subjected to an MIT test (R = 0.38 mm / Ube Kosan Co., Ltd. Upilex 12.5 μm base material used) to evaluate the flexibility. The case where it is bent for 120 cycles or more is marked with ◯. In this case, the flexibility as a flexible wiring board can be satisfied. When it was less than 120 cycles, it was set as x.

  The obtained results are shown in Table 4 below.

＊１２：合成例１のポリイミド樹脂
＊１３：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）
＊１４：ビスフェノールＡ型エポキシ樹脂，エポキシ当量１９０，質量平均分子量３８０（三菱化学（株）製）

* 12: Polyimide resin of Synthesis Example 1 * 13: Bisphenol A type epoxy resin (molecular weight 900) (manufactured by Mitsubishi Chemical Corporation)
* 14: Bisphenol A type epoxy resin, epoxy equivalent 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Corporation)

  As is clear from the results shown in Table 4, in Examples 15 and 16, an ion scavenger other than the hydrotalcite system is used in combination with the hydrotalcite ion scavenger in the adhesive layer resin composition, A flexible printed wiring board having a laminated structure formed using this has good insulation reliability and flame retardancy, and also has good flexibility. On the other hand, in Comparative Example 7, only the hydrotalcite-based ion scavenger is used in the resin composition for the adhesive layer, and the flexible printed wiring board having the laminated structure formed using the hydrotalcite-based resin has an insulating reliability. Was obtained, but flame retardancy decreased. Moreover, in Comparative Example 8, only the ion scavenger other than the hydrotalcite-based resin is used in the resin composition for the adhesive layer, and the flexible printed wiring board having the laminated structure formed using the ion trapping agent has an insulation reliability. Decreased. As a result, in these comparative examples, the insulation reliability and flame retardancy of the flexible printed wiring board could not be made highly compatible.

DESCRIPTION OF SYMBOLS 1 Printed wiring board 2 Conductor circuit 3 Resin layer (adhesion layer)
4 Resin layer (protective layer)
5 Mask

Claims (9)

  A curable resin composition containing a carboxyl group-containing resin, a thermosetting component, a flame retardant, and an ion scavenger, wherein the ion scavenger is a hydrotalcite-based ion scavenger and an ion scavenger other than a hydrotalcite-based agent And a curable resin composition.   2. The curable resin composition according to claim 1, wherein a mixing ratio of the hydrotalcite-based ion scavenger and the ion-trapping agent other than the hydrotalcite-based material is in a range of 100: 10 to 100: 500 on a mass basis. .   The curable resin composition according to claim 1, further comprising at least one of a photopolymerization initiator and a compound having an ethylenically unsaturated group.   The curable resin composition according to claim 1, which is a photosensitive resin composition containing a photopolymerization initiator.   The curable resin composition according to claim 1, wherein the thermosetting component is a cyclic (thio) ether compound.   The curable resin composition of Claim 1 used in order to form at least any one of a coverlay and a soldering resist.   A dry film comprising a resin layer formed by applying and drying the curable resin composition according to claim 1 on a film.   A curable resin composition according to claim 1 or a cured product obtained by curing the resin layer of the dry film according to claim 7. A printed wiring board comprising the cured product according to claim 8.

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