JP2020021758A - Printed wiring board with electromagnetic wave shield sheet - Google Patents

Abstract

To provide a printed wiring board with an electromagnetic wave shield sheet excellent in migration resistance, thermocompression bonding resistance, flexibility, light blocking effect, and incombustibility.SOLUTION: A printed wiring board with an electromagnetic wave shield sheet comprises an electromagnetic wave shield sheet, a cover coat layer, and a substrate with signal wiring and an insulating base material. The electromagnetic wave shield sheet has a phosphorus (P)-containing layer. The cover coat layer has a cured product of a resin layer containing a colorant. The shortest distance between the phosphorus (P)-containing layer and the signal wiring is in the range from 5 μm to 100 μm inclusive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printed wiring board with an electromagnetic wave shielding sheet.

  2. Description of the Related Art In recent years, flexible and flexible flexible printed circuit boards (hereinafter, referred to as FPCs) have become indispensable for electronic devices such as mobile phones, video cameras, and notebook computers, which are rapidly becoming smaller and thinner. Further, as the pitch of the built-in signal wiring becomes narrower and higher in frequency as the performance of electronic devices becomes higher, measures against electromagnetic wave noise have become increasingly important. Therefore, it is common to incorporate an electromagnetic wave shielding material that shields or absorbs electromagnetic wave noise generated from signal wiring into the FPC.

  The FPC is composed of a copper clad laminate (CCL) having a circuit formed by an etching process and a cover coat layer. The formation of the cover coat layer is generally selected from a cover lay film, a photosensitive ink (solder resist), a photosensitive film (dry resist film), and the like, and is easy to handle, durable, and insulating reliability. Due to their height, coverlay films are often used.

  A coverlay film is a material in which a thermosetting adhesive is applied to an insulating base material. As a use form using such a coverlay film, Patent Document 1 discloses that a conductive layer is formed on a cover coat layer of an FPC. An electromagnetic wave in which a shield layer having a conductive adhesive layer, a metal thin film layer, and the like is bonded together, and a conductive adhesive layer is joined to a ground wiring through an opening of a cover coat layer of the FPC to electrically connect the metal thin film layer. An FPC having a shielding function is disclosed. Further, Patent Document 2 discloses a shield film having a conductive adhesive layer containing an organic phosphorus-based flame retardant, a metal layer, and the like on a cover coat layer of an FPC.

  With the increase in the density of FPCs accompanying the reduction in size and size of electronic devices, a cover coat layer having a fine opening pattern has been required. Patent Literature 3 discloses an alkali developable resin, an epoxy resin, A resin composition and a dry film excellent in resolution and crack resistance by using a reaction initiator, a photopolymerizable monomer and a surface-treated inorganic filler have been proposed.

  The cover coat layer is also required to have high light-shielding properties from the viewpoints of information protection and visibility. Patent Document 4 discloses a compound having a carboxyl group and an ethylenically unsaturated group, urethane (meth) acrylate, Black photosensitive compositions and dry films having excellent shielding properties and storage stability have been proposed by using a polymerizable compound having an ethylenically unsaturated group other than the above, a photopolymerization initiator, and carbon black.

  Further, Patent Literature 5 proposes a resin composition for a solder resist and a solder resist film having excellent insulation properties by using a thermosetting resin, an inorganic filler, and a black pigment containing black titanium oxide.

JP 2007-294996 A WO2016 / 190278 JP-A-2006-177174 JP 2012-141605 A JP-A-2017-034213

  However, the cover coat layer is often a single layer structure without an insulating base material compared to the coverlay film, and when the electromagnetic wave shielding sheet is laminated, the cover coat layer flows due to heat and pressure at the time of lamination. In some cases, the thickness may be reduced (heat-resistant crimp resistance) or the migration resistance may be extremely deteriorated. In addition, due to the colorant used to provide light-shielding properties, curing by active energy rays is insufficient, not only is it difficult to form a fine opening, but also the migration resistance when an electromagnetic wave shielding sheet is laminated is more improved. Further deterioration is also a problem. If the crosslink density is increased to improve the migration resistance and the hardness of the film is increased, cracks may occur at the time of bending (flexibility), and it is difficult to achieve both migration resistance and flexibility. .

  That is, the problem to be solved by the present invention is to provide a printed wiring board with an electromagnetic wave shielding sheet which is excellent in migration resistance, heat-resistant crimp resistance, flexibility, light shielding properties and flame retardancy.

  The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, by controlling the shortest distance between the phosphorus (P) -containing layer of the electromagnetic wave shielding sheet and the signal wiring to a specific range, We have found that the above problems can be solved.

  That is, the present invention is a printed wiring board provided with an electromagnetic wave shielding sheet, comprising a substrate having an electromagnetic wave shielding sheet, a cover coat layer, a signal wiring and an insulating base material, wherein the electromagnetic wave shielding sheet is made of phosphorus (P ), The cover coat layer has a cured resin layer containing a colorant, and the shortest distance between the phosphorus (P) -containing layer and the signal wiring is 5 μm or more. The present invention relates to a printed wiring board with an electromagnetic wave shielding sheet, which is within a range of 100 μm or less.

  The present invention also relates to the printed wiring board with an electromagnetic wave shielding sheet, wherein the cured product of the resin layer has a storage elastic modulus at 85 ° C. of 1.0E + 06 to 1.0E + 10 Pa.

  Further, the present invention relates to the printed wiring board with the electromagnetic wave shielding sheet, wherein the electromagnetic wave shielding sheet has at least an insulating layer and a conductive layer, and the conductive layer contains phosphorus (P).

  Further, according to the present invention, the electromagnetic wave shielding sheet has at least an insulating layer and a conductive layer, wherein the conductive layer does not contain phosphorus (P) and the insulating layer contains phosphorus (P). The present invention relates to a printed wiring board with an electromagnetic wave shielding sheet.

  According to the present invention, it is possible to provide a printed wiring board with an electromagnetic wave shielding sheet, which is excellent in migration resistance, heat compression resistance, flexibility, light shielding properties, and flame retardancy.

FIG. 1 is a conceptual diagram illustrating a migration test.

  Hereinafter, an example of an embodiment to which the present invention is applied will be described. Note that the sizes and ratios of the respective members in the following drawings are for convenience of explanation, and are not limited thereto. In the present specification, the description “any number A to any number B” includes the number A as a lower limit and the number B as an upper limit in the range. The term “sheet” in this specification includes not only “sheet” defined in JIS but also “film”. The numerical values specified in the present specification are values obtained by the method disclosed in the embodiment or the example. In this specification, “parts” and “%” represent “parts by mass” and “% by mass”, respectively, unless otherwise specified.

  A printed wiring board with an electromagnetic wave shielding sheet according to the present invention is a printed wiring board with an electromagnetic wave shielding sheet, comprising: a substrate having an electromagnetic wave shielding sheet, a cover coat layer, a signal wiring and an insulating base material. Has a layer containing phosphorus (P), the cover coat layer has a cured product of a resin layer containing a colorant, and has a shortest distance between the layer containing phosphorus (P) and the signal wiring. The distance is within a range of 5 μm or more and 100 μm or less.

<Cover coat layer>
The cover coat layer is an insulating layer for covering the signal wiring of the base plate and protecting it from the external environment, and has a cured resin layer. Examples of a method of providing a resin layer on a substrate include a method of forming a dry resist film having a resin layer made of a curable resin composition and laminating the film on the substrate, and a method of directly applying the curable resin composition to the substrate. . By curing these resin layers, a cover coat layer can be obtained. Here, examples of the curable resin composition include an active energy ray-curable resin composition and / or a thermosetting resin composition. In the description of the embodiment to which the present invention is applied, an example using a dry resist film is mainly described, but the present invention is not limited thereto.

  The thickness of the cover coat layer is preferably from 5 to 100 μm, more preferably from 10 to 70 μm. By setting the thickness of the cover coat layer in the range of 5 to 100 μm, flexibility and migration resistance can be improved.

  The glass transition temperature (Tg) of the cover coat layer is preferably from 40C to 120C, more preferably from 50C to 100C. By setting the glass transition temperature (Tg) of the cover coat layer to 40 ° C. to 120 ° C., flexibility and migration resistance can be improved.

<Dry resist film>
The dry resist film has a resin layer containing a coloring agent. A curable resin composition may be used as a material for forming the resin layer. However, when patterning is performed using active energy rays such as light, it is preferable to use an active energy ray-curable resin composition. In addition, the active energy ray-curable resin composition referred to in the present specification refers to a composition containing an active energy ray-curable resin and an active energy ray polymerization initiator.

<Curable resin composition>
Curable resin compositions can be broadly classified into active energy ray-curable resin compositions and thermosetting resin compositions.

<Active energy ray-curable resin composition>
The active energy ray-curable resin composition contains an active energy ray-curable resin, an active energy ray polymerization initiator, and a colorant.

<Thermosetting resin composition>
The thermosetting resin composition contains a thermosetting resin, a thermosetting agent, and a coloring agent.

[resin]
As the resin, conventionally known thermoplastic resins and thermosetting resins can be used, but it is preferable to include an active energy ray-curable resin. The active energy ray-curable resin is a resin having curability by irradiation with an active energy ray, and is preferably a compound having an ethylenically unsaturated double bond. Further, in order to impart developability, it is preferably alkali-soluble.

  The mass average molecular weight (Mw) of the resin is preferably 2,000 to 40,000, more preferably 3,000 to 30,000. By setting the Mw of the resin to 2000 to 40000, alkali solubility can be improved and patterning properties can be excellent.

  The active energy ray-curable resin can be used alone, but from the viewpoint of further improving the patterning property, it is preferable to use a thermosetting resin in combination. When a thermosetting resin is used in combination, the compounding ratio of the active energy ray-curable resin to the thermosetting resin is preferably 30:70 to 70:30, and 40:60 to 60:30 in terms of the solid content of the resin. 40 is more preferred. By setting the mixing ratio of the active energy ray-curable resin and the thermosetting resin within the above range, the patterning property is improved.

(Active energy ray curable resin)
As the active energy ray-curable resin, it is preferable to use an alkali-soluble acrylic resin obtained by copolymerizing an acidic group-containing ethylenically unsaturated monomer. In order to further improve the active energy ray sensitivity and the like, an active energy ray-curable resin having an ethylenically unsaturated double bond can be used.
The acid value of the active energy ray-curable resin is preferably from 50 to 120 mgKOH / g, more preferably from 60 to 110 mgKOH / g. By setting the acid value of the active energy ray-curable resin to 50 to 120 mgKOH / g, patterning properties and migration resistance are improved.

  Examples of the acrylic alkali-soluble resin obtained by copolymerizing an acidic group-containing ethylenically unsaturated monomer include a resin having an acidic group such as a carboxyl group and a sulfone group. Specific examples of the alkali-soluble resin include an acrylic resin having an acidic group, an α-olefin / (anhydride) maleic acid copolymer, a styrene / styrene sulfonic acid copolymer, an ethylene / (meth) acrylic acid copolymer, or Isobutylene / (anhydride) maleic acid copolymer; Above all, an acrylic resin having an acidic group and at least one resin selected from a styrene / styrene sulfonic acid copolymer, and particularly an acrylic resin having an acidic group, are preferably used because of their high migration resistance.

  Examples of the resin having an ethylenically unsaturated double bond include a resin having an ethylenically unsaturated double bond introduced by the following method (i) or (ii).

・ Method (i)
As the method (i), for example, the side chain epoxy group of a copolymer obtained by copolymerizing an ethylenically unsaturated monomer having an epoxy group and one or more other monomers is used. The carboxyl group of an unsaturated monobasic acid having an ethylenically unsaturated double bond is subjected to an addition reaction, and further, the generated hydroxyl group is reacted with a polybasic acid anhydride to form an ethylenically unsaturated double bond and a carboxyl group. There is a way to introduce it.

  Examples of the ethylenically unsaturated monomer having an epoxy group include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 2-glycidoxyethyl (meth) acrylate, and 3,4-epoxybutyl (meth) acrylate And 3,4-epoxycyclohexyl (meth) acrylate. These may be used alone or in combination of two or more. Glycidyl (meth) acrylate is preferred from the viewpoint of reactivity with the unsaturated monobasic acid in the next step.

  Examples of the unsaturated monobasic acid include (meth) acrylic acid, crotonic acid, o-, m-, p-vinylbenzoic acid, α-haloalkyl (meth) acrylic acid, alkoxyl, halogen, nitro and cyano-substituted products. Monocarboxylic acids may be used, and these may be used alone or in combination of two or more.

  Examples of polybasic acid anhydrides include tetrahydrophthalic anhydride, phthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, maleic anhydride and the like, and these may be used alone or in combination of two or more. I don't care. Increasing the number of carboxyl groups, etc., if necessary, using a tricarboxylic anhydride such as trimellitic anhydride, or using a tetracarboxylic dianhydride such as pyromellitic dianhydride, the remaining anhydride Hydrolysis of the group can also be performed. When tetrahydrophthalic anhydride or maleic anhydride having an ethylenically unsaturated double bond is used as the polybasic acid anhydride, the number of ethylenically unsaturated double bonds can be further increased.

  As a similar method to the method (i), for example, a side chain of a copolymer obtained by copolymerizing an ethylenically unsaturated monomer having a carboxyl group with one or more other monomers. There is a method in which an ethylenically unsaturated monomer having an epoxy group is subjected to an addition reaction to a part of the carboxyl group to introduce an ethylenically unsaturated double bond and a carboxyl group.

・ Method (ii)
In the method (ii), an ethylenically unsaturated monomer having a hydroxyl group is used, and another monomer of an unsaturated monobasic acid having a carboxyl group or another monomer is copolymerized. There is a method of reacting an isocyanate group of an ethylenically unsaturated monomer having an isocyanate group with a side chain hydroxyl group of the obtained copolymer.

  Examples of the ethylenically unsaturated monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 2- or 3- or 4-hydroxybutyl (meth) acrylate, glycerol Examples thereof include hydroxyalkyl (meth) acrylates such as (meth) acrylate and cyclohexanedimethanol mono (meth) acrylate, and these may be used alone or in combination of two or more. Further, a polyether mono (meth) acrylate obtained by addition-polymerizing ethylene oxide, propylene oxide, and / or butylene oxide to the above hydroxyalkyl (meth) acrylate, (poly) γ-valerolactone, (poly) ε-caprolactone And / or (poly) ester mono (meth) acrylate to which (poly) 12-hydroxystearic acid or the like has been added.

  Examples of the ethylenically unsaturated monomer having an isocyanate group include 2- (meth) acryloyloxyethyl isocyanate and 1,1-bis [(meth) acryloyloxy] ethyl isocyanate, but are not limited thereto. Instead, two or more types can be used in combination.

  It is also preferable to use a photosensitive resin (A) as the active energy ray-curable resin. Hereinafter, the photosensitive resin (A) will be described. As described below, the photosensitive resin (A) is a hydroxyl group-containing photosensitive resin (A-1) or a carboxyl group-containing photosensitive resin (A-2). The hydroxyl group-containing photosensitive resin (A-1) has, as a first step, an epoxy compound (a) having at least two epoxy groups in one molecule and at least two phenolic hydroxyl groups in one molecule. The side chain hydroxyl group-containing resin (c) is prepared by reacting with the phenol compound (b). Next, as a second step, the carboxyl group-containing resin (e) is prepared by reacting the side chain hydroxyl group-containing resin (c) with the polybasic acid anhydride (d). Further, as a third step, it is obtained by reacting the carboxyl group-containing resin (e) with an epoxy group or an oxetane group in the compound (f) having an epoxy group or an oxetane group and an ethylenically unsaturated group. be able to. Further, as the fourth step, the carboxyl group-containing photosensitive resin (A-2) is obtained by the acid anhydride group in the hydroxyl group polybasic acid anhydride (d) in the hydroxyl group-containing resin (A-1). be able to. Hereinafter, the method for producing the photosensitive resin (A) will be described in detail.

  First, the side chain hydroxyl group-containing resin (c) obtained in the first step will be described. The side chain hydroxyl group-containing resin (c) reacts an epoxy compound (a) having at least two epoxy groups in one molecule with a phenol compound (b) having at least two phenolic hydroxyl groups in one molecule. And a phenol compound (b) having at least two phenolic hydroxyl groups in one molecule and an epoxy group in the epoxy compound (a) having at least two epoxy groups in one molecule. It is preferable that the phenolic hydroxyl group is prepared by reacting with a phenolic hydroxyl group at a molar ratio of epoxy group / phenolic hydroxyl group = 1/1 to 1 / 2.5. If the phenolic hydroxyl group is less than the above molar ratio range, the remaining excess epoxy group may react in the subsequent synthesis step to cause gelation. Further, when the phenolic hydroxyl group is more than the above molar ratio, the molecular weight of the photosensitive resin (A) finally obtained becomes low, and it becomes difficult to obtain desired coating film resistance and film formability. Furthermore, the surplus phenol compound (b) having at least two phenolic hydroxyl groups in one molecule may adversely affect physical properties such as solder heat resistance and electrical insulation.

  In the present invention, the term "molar ratio" refers to a molar ratio at which functional groups actually react with each other, and various starting materials are used in an amount that enables the reaction at the above molar ratio. Therefore, for example, in the reaction of “the epoxy compound (a) having at least two epoxy groups in one molecule” and “the phenol compound (b) having at least two phenolic hydroxyl groups in one molecule”, When the starting material is charged, the amount of “at least two phenolic hydroxyl groups in one molecule is based on 1.0 mol of epoxy groups in the“ epoxy compound (a) having at least two epoxy groups in one molecule ”. The phenolic hydroxyl group in the "phenol compound (b)" may be charged in an amount exceeding 2.5 mol (preferably with an upper limit of 2.7 mol) and reacted.

  The epoxy compound (a) having at least two epoxy groups in one molecule used in the present invention is preferably a compound containing two epoxy groups in a molecule, and is not particularly limited. Specifically, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, tetramethylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, 1,6- Hexanediol diglycidyl ether, bisphenol A / epichlorohydrin type epoxy resin, bisphenol F / epichlorohydrin type epoxy resin, biphenol / epichlorohydrin type epoxy resin, polyglycidyl ether of glycerin / epichlorohydrin adduct , Resorcinol diglycidyl ether, polybutadiene diglycidyl ether, hydroquinone diglycidyl ether, dibromoneope Tyl glycol diglycidyl ether, neopentyl glycol diglycidyl ether, hexahydrophthalic acid diglycidyl ester, hydrogenated bisphenol A type diglycidyl ether, dihydroxyanthracene type epoxy resin, polypropylene glycol diglycidyl ether, diphenylsulfone diglycidyl ether, dihydroxybenzophenone Diglycidyl ether, biphenol diglycidyl ether, diphenylmethane diglycidyl ether, bisphenol full orange glycidyl ether, biscresol full orange glycidyl ether, bisphenoxyethanol full orange glycidyl ether, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane , N, N-diglycidylaniline, N, N-jig Risidyl toluidine, an epoxy compound having excellent flexibility disclosed in JP-A-2004-156024, JP-A-2004-315595, and JP-A-2004-323777, and the following formulas (1) to (3) And the like.

  Among them, polyethylene glycol diglycidyl ether is preferable when imparting flexibility and solubility in an alkali developer to the finally obtained hydroxyl group-containing photosensitive resin (A-1), and bisphenol A / epichlorohydrin type Epoxy resins are preferred when imparting heat resistance to the finally obtained carboxyl group-containing modified ester resin (A). As described above, in the present invention, the epoxy compound (d) having at least two epoxy groups in one molecule can be selected according to the purpose, and these can be used alone or in combination. It is also preferable to use them in combination.

The phenol compound (b) having at least two phenolic hydroxyl groups in one molecule used in the present invention is not particularly limited as long as it is a compound containing two phenolic hydroxyl groups in the molecule. For example, 2,2-bis (4-hydroxyphenyl) propane (alias: bisphenol A) is a typical example, and bis (4-hydroxyphenol) methane and 1,1-bis (4-hydroxyphenyl) are also typical examples. ) Ethane, 1,1-bis (4-hydroxyphenyl) -n-propane, 1,1-bis (4-hydroxyphenyl) -n-butane, 1,1-bis (4-hydroxyphenyl) -n-pentane 1,1-bis (4-hydroxyphenyl) -n-hexane, 1,1-bis (4-hydroxyphenyl) -n-heptane, 1,1-bis (4-hydroxyphenyl) -n-octane, 1,1-bis (4-hydroxyphenyl) -n-nonane, 1,1-bis (4-hydroxyphenyl) -n-decane, bis (4-hydroxyphenyl) phenylmethane, (4-hydroxyphenyl) naphthylmethane, bis (4-hydroxyphenyl) toluylmethane, bis (4-hydroxyphenyl)-(4-ethylphenyl) methane, bis (4-hydroxyphenyl)-(4-n-propylphenyl ) Methane, bis (4-hydroxyphenyl)-(4-isopropylphenyl) methane, bis (4-hydroxyphenyl)-(4-n-butylphenyl) methane, bis (4-hydroxyphenyl)-(4-pentylphenyl) ) Methane, bis (4-hydroxyphenyl)-(4-hexylphenyl) methane, bis (4-hydroxyphenyl)-(4-fluorophenyl) methane, bis (4-hydroxyphenyl)-(4-chlorophenyl) methane, Bis (4-hydroxyphenyl)-(2-fluorophenyl) meth Bis (4-hydroxyphenyl)-(2-chlorophenyl) methane, bis (4-hydroxyphenyl) tetrafluorophenylmethane, bis (4-hydroxyphenyl) tetrachlorophenylmethane, bis (3-methyl-4-hydroxyphenyl) ) Methane, bis (3,5-dimethyl-4-hydroxyphenyl) methane, bis (3-ethyl-4-hydroxyphenyl) methane, bis (3-isobutyl-4-hydroxyphenyl) methane, bis (3-t- Butyl-4-hydroxyphenyl) -1-phenylmethane, bis (3-phenyl-4-hydroxyphenyl) -1-phenylmethane, bis (3-fluoro-4-hydroxyphenyl) methane, bis (3,5-difluoro -4-hydroxyphenyl) methane, bis (3-chloro-4-hydro (Xyphenyl) methane, bis (3,5-dichloro-4-hydroxyphenyl) methane, 1,1-bis (3-methyl-4-hydroxyphenyl) ethane, 1,1-bis (3,5-dimethyl-4-) Hydroxyphenyl) ethane, 1,1-bis (3-ethyl-4-hydroxyphenyl) ethane, 1,1-bis (3-isobutyl-4-hydroxyphenyl) ethane, 1,1-bis (3-fluoro-4 -Hydroxyphenyl) ethane, 1,1-bis (3,5-difluoro-4-hydroxyphenyl) ethane, 1,1-bis (3-chloro-4-hydroxyphenyl) ethane, 1,1-bis (3 Bisphenols having a hydrogen atom bonded to the central carbon such as 5-dichloro-4-hydroxyphenyl) ethane;
2,2-bis (4-hydroxyphenyl) -n-butane, 2,2-bis (4-hydroxyphenyl) -n-pentane, 2,2-bis (4-hydroxyphenyl) -n-hexane, 2, 2-bis (4-hydroxyphenyl) -n-heptane, 2,2-bis (4-hydroxyphenyl) -n-octane, 2,2-bis (4-hydroxyphenyl) -n-nonane, 2,2- Bis (4-hydroxyphenyl) -n-decane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane (commonly known as bisphenol P), 1,1-bis (4-hydroxyphenyl) -1-naphthylethane 1,1-bis (4-hydroxyphenyl) -1-toluylethane, 1,1-bis (4-hydroxyphenyl) -1- (4-ethylphenyl) ethane, 1,1-bis (4 (Hydroxyphenyl) -1- (4-n-propylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1- (4-isopropylphenyl) ethane, 1,1-bis (4-hydroxyphenyl)- 1- (4-n-butylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1- (4-pentylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1- (4 -Hexylphenyl) ethane, 1,1-bis (3-t-butyl-4-hydroxyphenyl) -1-phenylethane, 1,1-bis (3-phenyl-4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1- (4-fluorophenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1- (4-chlorophenyl) Tan, 1,1-bis (4-hydroxyphenyl) -1- (2-fluorophenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1- (2-chlorophenyl) ethane, 1,1-bis Bisphenols such as (4-hydroxyphenyl) -1-tetrafluorophenylethane and 1,1-bis (4-hydroxyphenyl) -1-tetrachlorophenylethane having one methyl group bonded to the central carbon;
2,2-bis (3-methyl-4-hydroxyphenyl) propane (commonly known as bisphenol C), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3-ethyl -4-hydroxyphenyl) propane, 2,2-bis (3-isobutyl-4-hydroxyphenyl) propane, 2,2-bis (3-fluoro-4-hydroxyphenyl) propane, 2,2-bis (3 Central carbon such as 5-difluoro-4-hydroxyphenyl) propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane Bisphenols in which two methyl groups are bonded to:
Bis (4-hydroxyphenyl) -1,1-diphenylmethane, bis (3-methyl-4-hydroxyphenyl) -1,1-diphenylmethane, bis (3-t-butyl-4-hydroxyphenyl) -1,1- Bisphenols which are diphenylmethane derivatives such as diphenylmethane, bis (3-phenyl-4-hydroxyphenyl) -1,1-diphenylmethane, bis (3-chloro-4-hydroxyphenyl) -1,1-diphenylmethane;
1,1-bis (4-hydroxyphenyl) cyclohexane (commonly known as bisphenol Z), 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3,5-dimethyl-4-hydroxy) Phenyl) cyclohexane, 1,1-bis (3-ethyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3-isobutyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3-fluoro-4- (Hydroxyphenyl) cyclohexane, 1,1-bis (3,5-difluoro-4-hydroxyphenyl) cyclohexane, 1,1-bis (3-chloro-4-hydroxyphenyl) cyclohexane, 1,1-bis (3,5 Bis (dichloro-4-hydroxyphenyl) cyclohexane; Nord like;
1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3-methyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1- Bis (3,5-dimethyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3-ethyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1-bis (3-isobutyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3-fluoro-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, -3,3,5-trimethylcyclohexane such as 1-bis (3,5-difluoro-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane Bisphenols is Rohekisan derivatives;
9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) fluorene, 9 , 9-bis (3-ethyl-4-hydroxyphenyl) fluorene, 9,9-bis (3-isobutyl-4-hydroxyphenyl) fluorene, 1,1-bis (3-fluoro-4-hydroxyphenyl) fluorene, Bisphenols which are fluorene derivatives such as 9,9-bis (3,5-difluoro-4-hydroxyphenyl) fluorene;
1,1-bis (4-hydroxyphenyl) -cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclooctane, 1,1-bis (4 Bisphenols which are cycloalkane derivatives such as -hydroxyphenyl) cyclononane and 1,1-bis (4-hydroxyphenyl) cyclodecane;
Biphenols having an aromatic ring directly bonded, such as 4,4'-biphenol;
Bis (4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, bis (3-ethyl-4-hydroxyphenyl) sulfone, Bisphenols which are sulfone derivatives such as bis (3-isobutyl-4-hydroxyphenyl) sulfone, bis (3-fluoro-4-hydroxyphenyl) sulfone, bis (3,5-difluoro-4-hydroxyphenyl) sulfone;
Bis (4-hydroxyphenyl) ether, bis (3-methyl-4-hydroxyphenyl) ether, bis (3,5-dimethyl-4-hydroxyphenyl) ether, bis (3-ethyl-4-hydroxyphenyl) ether, Bisphenols having an ether bond such as bis (3-isobutyl-4-hydroxyphenyl) ether, bis (3-fluoro-4-hydroxyphenyl) ether, bis (3,5-difluoro-4-hydroxyphenyl) ether;
Bis (4-hydroxyphenyl) sulfide, bis (3-methyl-4-hydroxyphenyl) sulfide, bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, bis (3-ethyl-4-hydroxyphenyl) sulfide, Bisphenols having a sulfide bond such as bis (3-isobutyl-4-hydroxyphenyl) sulfide, bis (3-fluoro-4-hydroxyphenyl) sulfide, bis (3,5-difluoro-4-hydroxyphenyl) sulfide;
Bis (4-hydroxyphenyl) sulfoxide, bis (3-methyl-4-hydroxyphenyl) sulfoxide, bis (3,5-dimethyl-4-hydroxyphenyl) sulfoxide, bis (3-ethyl-4-hydroxyphenyl) sulfoxide, Bisphenols which are sulfoxide derivatives such as bis (3-isobutyl-4-hydroxyphenyl) sulfoxide, bis (3-fluoro-4-hydroxyphenyl) sulfoxide, bis (3,5-difluoro-4-hydroxyphenyl) sulfoxide;
Bisphenols having a hetero atom-containing aliphatic ring such as phenolphthalein;
Bis (2,3,5,6-tetrafluoro-4-hydroxyphenyl) difluoromethane, 1,1-bis (2,3,5,6-tetrafluoro-4-hydroxyphenyl) perfluoroethane, 2,2 Bisphenols having no carbon-hydrogen bond, such as -bis (2,3,5,6-tetrafluoro-4-hydroxyphenyl) perfluoropropane;

Further, dihydroxybenzenes such as hydroquinone, resorcinol, catechol, and methylhydroquinone;
Examples thereof include dihydroxynaphthalenes such as 1,5-dihydroxynaphthalene and 2,6-dihydroxynaphthalene.

  In the present invention, the conditions for synthesizing the side chain hydroxyl group-containing resin (c) are not particularly limited, and the synthesis can be performed under known conditions. For example, a flask is charged with an epoxy compound (a) having at least two epoxy groups in one molecule, a phenol compound (b) having at least two phenolic hydroxyl groups in one molecule, and a solvent, and stirred. By heating at 100 to 150 ° C., the side chain hydroxyl group-containing resin (c) can be obtained. At this time, a catalyst such as triphenylphosphine or a tertiary amino group-containing compound may be used as necessary.

  Next, the carboxyl group-containing resin (e) obtained in the second step will be described. The carboxyl group-containing resin (e) can be obtained by reacting the side chain hydroxyl group-containing resin (c) with the polybasic anhydride (d), and the hydroxyl group in the side chain hydroxyl group-containing resin (c) can be obtained. It is preferable to react with the acid anhydride group in the polybasic acid anhydride (d) in a molar ratio of hydroxyl group / acid anhydride group = 1 / 0.1 to 1/1. When the amount of the acid anhydride group is less than the above molar ratio, the concentration of the carboxyl group functioning as a crosslinking point in the finally obtained photosensitive resin (A) decreases, so that the desired heat resistance and solubility in an alkali developing solution are obtained. Is difficult to obtain. Further, when the number of the acid anhydride groups is larger than the above molar ratio, the excess polybasic acid anhydride (d) generates a by-product in a subsequent synthesis step, so that the flexibility and solder heat resistance of the final coating film, Insulation reliability tends to decrease.

  The polybasic acid anhydride (d) used in the present invention is not particularly limited as long as it is a compound containing one or more acid anhydride groups in the molecule. For example, phthalic anhydride, trimellitic anhydride, methyltetrahydrophthalic anhydride, methylhymic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylpentahydrophthalic anhydride, methyltrihydrophthalic anhydride, trialkyltetrahydro Compounds containing an acid anhydride group having an alicyclic structure or an aromatic ring structure, such as phthalic anhydride, methylcyclohexenedicarboxylic anhydride, heptic anhydride, and tetrabromophthalic anhydride, may be mentioned. Other compounds include succinic anhydride, maleic anhydride, glutaric anhydride, butylsuccinic anhydride, hexylsuccinic anhydride, octylsuccinic anhydride, dodecylsuccinic anhydride, butylmaleic anhydride, pentylmaleic acid Anhydride, hexylmaleic anhydride, octylmaleic anhydride, decylmaleic anhydride, dodecylmaleic anhydride, butylglutamic anhydride, hexylglutamic anhydride, heptylglutamic anhydride, octylglutamic anhydride, decylglutamic anhydride And dodecylglutamic anhydride. In the present invention, as the polybasic acid anhydride (d), only one kind may be used alone, or two or more kinds may be used in combination.

  Among them, succinic anhydride, tetrahydrophthalic anhydride, and the like are particularly preferable in the present invention because the patterning property, pattern forming property, and coating film resistance are extremely excellent.

  In the present invention, the conditions for synthesizing the carboxyl group-containing resin (e) are not particularly limited, and the synthesis can be performed under known conditions. For example, a side chain hydroxyl group-containing resin (c), a polybasic acid anhydride (d), and a solvent are charged into a flask, and heated at 25 to 150 ° C. while stirring, to thereby prepare a side chain hydroxyl group-containing resin (c). Can be obtained. Although this reaction proceeds even without a catalyst, a catalyst such as a tertiary amino group-containing compound may be used if necessary.

  Next, the hydroxyl group-containing resin (A-1) obtained in the third step will be described. The hydroxyl group-containing resin (A-1) can be obtained by reacting the carboxyl group-containing resin (e) with a compound (f) having an epoxy group or an oxetane group and an ethylenically unsaturated group. The carboxyl group in the containing resin (e) and the epoxy group or oxetane group in the compound (f) having an epoxy group or oxetane group and an ethylenically unsaturated group are converted into carboxyl group / epoxy group or oxetane group = 1 / It is preferable to make it by reacting at a molar ratio of 0.1 to 1/1. When the epoxy group or the oxetane group is less than the above molar ratio, the double bond equivalent functioning as a photocrosslinking point in the finally obtained photosensitive resin (A) becomes high, so that the desired heat resistance or coating film is obtained. It becomes difficult to obtain resistance. When the number of epoxy groups or oxetane groups is larger than the above molar ratio, the compound (f) having an excess epoxy group or oxetane group and an ethylenically unsaturated group tends to lower the flexibility of the final coating film. .

  The compound (f) having an epoxy group or oxetane group and an ethylenically unsaturated group used in the present invention may be a compound containing at least one epoxy group or oxetane group and one or more ethylenically unsaturated groups in a molecule. However, there is no particular limitation. For example, glycidyl (meth) acrylate, glycidyl cinnamate, 4-hydroxybutyl (meth) acrylate glycidyl ether, glycidyl allyl ether, 2,3-epoxy-2-methylpropyl (meth) acrylate, (3,4-epoxycyclohexyl) Hydroxyl-containing poly (meth) acrylates such as methyl (meth) acrylate, 4-vinyl-1-cyclohexene-1,2-epoxide, 1,3-butadiene monoepoxide, oxetanyl (meth) acrylate, oxetanyl cinnamic acid, and pentaerythritol triacrylate; Modification of polyepoxyhydrin-containing monoepoxide obtained by reacting epichlorohydrin with hydroxyl group of functional acrylic monomer, or modification of most epoxy groups of phenol novolak type epoxy resin to acrylate groups with acrylic acid The obtained epoxy of a compound having two or more epoxy groups in the molecule in a carboxyl group of a polyfunctional acrylate group-containing monoepoxide and a carboxyl group-containing polyfunctional acrylic monomer having one epoxy group remaining in one molecule on average. Examples include monofunctional epoxides containing a polyfunctional acrylate group obtained by reacting a part of the groups. By reacting these epoxy groups or oxetane groups with a carboxyl group in the carboxyl group-containing resin (e), The group-containing resin (A-1) is obtained. In the present invention, the compound (f) having an epoxy group or an oxetane group and an ethylenically unsaturated group may be used alone or in combination of two or more.

  Among them, glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and the like are particularly preferred in the present invention because they have high reactivity with carboxyl groups and are extremely excellent in photosensitivity.

  In the present invention, a compound having an epoxy group or an oxetane group having no ethylenically unsaturated group and used in combination with a compound (b) having an epoxy group or an oxetane group and an ethylenically unsaturated group is used. Can also. In this case, it is possible to control the photosensitivity of the photosensitive urethane resin (A) containing a carboxyl group more widely. Examples of compounds having no ethylenically unsaturated group and having an epoxy group or an oxetane group include, for example, styrene oxide, phenyl glycidyl ether, o-phenylphenol glycidyl ether, p-phenylphenol glycidyl ether, glycidyl cinnamate, methyl glycidyl Ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, decyl glycidyl ether, stearyl glycidyl ether, allyl glycidyl ether, glycidol, N-glycidyl phthalimide, 1,3-dibromophenyl glycidyl ether, celloxide 2000 (manufactured by Daicel Chemical Industries, Ltd.) And oxetane alcohol.

  In the present invention, the conditions for synthesizing the hydroxyl group-containing resin (A-1) are not particularly limited, and the synthesis can be performed under known conditions. For example, in a flask, in the presence of oxygen, the carboxyl group-containing resin (e), the compound (f) having an epoxy group or an oxetane group and an ethylenically unsaturated group, and a solvent are charged, and the mixture is stirred at 25 to 150 ° C. By heating, the hydroxyl group-containing resin (A-1) can be obtained. At this time, a reaction catalyst such as a tertiary amino group-containing compound is added as necessary to promote the reaction, or an ethylenically unsaturated group is added so as not to cause a polymerization reaction or gelation due to polymerization progress. Or a molecular oxygen.

  Examples of the polymerization inhibitor include hydroquinone, methylhydroquinone, pt-butylcatechol, 2-t-butylhydroquinone, 2,5-di-t-butylhydroquinone, trimethylhydroquinone, methoxyhydroquinone, p-benzoquinone, and 2,5- Di-t-butylbenzoquinone, naphthoquinone, phenothiazine, N-oxyl compound and the like can be used. In addition, the presence of molecular oxygen in the reaction vessel has a polymerization inhibiting effect. For example, so-called bubbling, in which air or a mixed gas of air and an inert gas such as nitrogen is blown into the reaction vessel, may be performed. In order to enhance the polymerization inhibiting effect, it is preferable to use a polymerization inhibitor and molecular oxygen in combination.

  Next, the carboxyl group-containing photosensitive resin (A-2) obtained in the fourth step will be described. The carboxyl group-containing photosensitive resin (A-2) can be obtained by reacting the hydroxyl group-containing resin (A-1) with the polybasic acid anhydride (d). )) And the acid anhydride group in the polybasic acid anhydride (d) in a molar ratio of hydroxyl group / acid anhydride group of 1 / 0.01 to 1/1. preferable. When the amount of the acid anhydride group is less than the above molar ratio, the concentration of the carboxyl group functioning as a crosslinking point in the finally obtained photosensitive resin (A) decreases, so that the desired heat resistance and solubility in an alkali developing solution are obtained. Is difficult to obtain. When the number of acid anhydride groups is larger than the above range, the excess polybasic acid anhydride (d) tends to decrease the flexibility, solder heat resistance, and insulation reliability of the final coating film.

  As described above, the polybasic acid anhydride (d) used in the present invention may be any compound containing one or more acid anhydride groups in the molecule, and is not particularly limited. These may be used, or a plurality of them may be used in combination. Among them, succinic anhydride, tetrahydrophthalic anhydride, and the like are particularly preferable in the present invention because the patterning property, pattern forming property, and coating film resistance are extremely excellent.

  In the present invention, the conditions for synthesizing the carboxyl group-containing photosensitive resin (A-2) are not particularly limited, and the hydroxyl group-containing resin (A-1) is placed in a flask in the presence of oxygen as in the third step. ), A polybasic acid anhydride (d), and a solvent, and the reaction is preferably performed by heating while heating and stirring at 25 to 150 ° C. If necessary, a suitable reaction catalyst and an ethylenically unsaturated group may be used. A new polymerization inhibitor can be added.

  The acid value of the photosensitive resin (A) is preferably from 50 to 120 mgKOH / g, and more preferably from 60 to 110 mgKOH / g. If the acid value is less than 50 mgKOH / g, it may be difficult to obtain sufficient patterning properties. For example, a film may remain as a residue at a portion where the film is to be dissolved and removed during development. On the other hand, when the acid value exceeds 120 mgKOH / g, the solubility of the coating film in the developing solution becomes high, and even the portion which is to be left as a pattern after being light-cured is dissolved, and the shape of the pattern may be deteriorated.

  The ethylenically unsaturated group equivalent of the photosensitive resin (A) is preferably from 200 to 5000 g / eq, more preferably from 300 to 3000 g / eq. If the ethylenically unsaturated group equivalent is less than 200 g / eq, the photosensitivity may be too high, and even the portion where the film is to be dissolved and removed during development is cured by light, and a good pattern shape is obtained. May not be. When the ethylenically unsaturated group equivalent exceeds 5,000 g / eq, the photosensitivity may be too low, the portion desired to be photocured is not sufficiently cured, and the pattern is dissolved at the time of development to obtain a good pattern shape. May not be. In the present invention, the term "ethylenically unsaturated group equivalent" is a theoretical value calculated from the mass of raw materials used in the synthesis of the resin, and the mass of the resin is defined as the ethylenically unsaturated group present in the resin. It is divided by the number of groups, and corresponds to the mass of the resin per mole of the ethylenically unsaturated group, that is, the reciprocal of the concentration of the ethylenically unsaturated group.

  The weight average molecular weight of the photosensitive resin (A) is preferably from 2,000 to 40,000, and more preferably from 3,000 to 30,000. When the mass average molecular weight is 2000 or more, solder heat resistance and flexibility are excellent, and when the mass average molecular weight is 40000 or less, patterning properties can be improved.

  The solvent used for the synthesis of the photosensitive resin (A) can be appropriately selected depending on the final use and the solubility of the reactants. In the dry film forming step, it is preferable to use a solvent having a low boiling point in order to quickly dry the solvent. In this case, examples of the low boiling point solvent include methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, tetrahydrofuran, toluene, and isopropyl alcohol.

  In the present invention, only one of these solvents may be used alone, if necessary, or a plurality of these solvents may be used in combination. May be added.

  Since the photosensitive resin (A) described above does not have an ester bond derived from half-esterification with a dibasic acid anhydride or a urethane bond derived from the reaction between an isocyanate group and a hydroxyl group in the main chain, the main chain is chemically stable. As a result, the resulting cover coat layer has excellent resistance to various coatings, exhibits excellent heat resistance even when exposed to high-temperature conditions such as a solder bath, and has excellent electrical insulation even under high temperature and high humidity. It is preferable to exhibit. Furthermore, since the photosensitive resin (A) has a photosensitive group and a carboxyl group in the side chain, it exhibits extremely excellent patterning properties even when the amount of the photosensitive group and the carboxyl group contained is small. . The functional groups introduced into these side chains are more reactive than those directly linked to the main chain, and the amount of introduction can be arbitrarily adjusted as compared to the case where they are introduced only at the ends of the main chain, so that excellent light It can exhibit curability, patterning properties, and coating film resistance.

(Thermosetting resin)
The thermosetting resin is a resin having a plurality of functional groups that can be used for a crosslinking reaction by heating. Examples of the functional group include a hydroxyl group, a phenolic hydroxyl group, a carboxyl group, an amino group, an epoxy group, an oxetanyl group, an oxazoline group, an oxazine group, an aziridine group, a thiol group, and a silanol group.
Thermosetting resin having the above functional group, for example, acrylic resin, maleic acid resin, polybutadiene resin, polyester resin, condensation type polyester resin, addition type polyester resin, melamine resin, polyurethane resin, polyurethane urea resin, epoxy resin Oxetane resin, phenoxy resin, polyimide resin, polyamide resin, polyamideimide resin, phenolic resin, alkyd resin, amino resin, polylactic acid resin, oxazoline resin, benzoxazine resin, silicone resin, fluorine resin and the like.

[Thermosetting agent]
The thermosetting agent forms a cover coat layer having excellent migration resistance and flexibility by thermally crosslinking with a carboxylic acid group and a hydroxyl group of an active energy ray-curable resin or a thermosetting resin. The thermosetting agent has a plurality of functional groups that can react with the functional groups of the active energy ray-curable resin and the thermosetting resin. Examples of the thermosetting agent include known compounds such as an epoxy compound, an acid anhydride group-containing compound, an isocyanate compound, an aziridine compound, an amine compound, and a phenol compound, and an isocyanate compound is particularly preferable.

  The isocyanate compound is not particularly limited as long as it is a compound having an isocyanate group in the molecule. Specifically, examples of the diisocyanate compound include an aromatic diisocyanate having 4 to 50 carbon atoms, an aliphatic diisocyanate, an araliphatic diisocyanate, and an alicyclic diisocyanate.

  Examples of the aromatic diisocyanate include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6- Tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', 4 "-Triphenylmethane triisocyanate.

  Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, , 4,4-trimethylhexamethylene diisocyanate.

  Examples of the aromatic aliphatic diisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene, , 4-tetramethylxylylene diisocyanate, 1,3-tetramethyl xylylene diisocyanate, and the like.

  Examples of the alicyclic diisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate [also called isophorone diisocyanate], 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, and 1,4-cyclohexane diisocyanate. , Methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) Cyclohexane and the like can be mentioned.

  As the isocyanate compound having one or more isocyanate groups in the molecule, specifically, as a monofunctional isocyanate having one isocyanate group in the molecule, (meth) acryloyloxyethyl isocyanate, 1,1 -Bis [(meth) acryloyloxymethyl] ethyl isocyanate, vinyl isocyanate, allyl isocyanate, (meth) acryloyl isocyanate, isopropenyl-α, α-dimethylbenzyl isocyanate and the like. Also, 1,6-diisocyanatohexane, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, xylylene diisocyanate, tolylene 2,4-diisocyanate, toluene diisocyanate, 2,4-diisocyanate Toluene, hexamethylene diisocyanate, 4-methyl-m-phenylene diisocyanate, naphthylene diisocyanate, paraphenylene diisocyanate, tetramethyl xylylene diisocyanate, cyclohexyl methane diisocyanate, hydrogenated xylylene diisocyanate, cyclohexyl diisocyanate, tolidine diisocyanate, 2,2 2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate Compounds obtained by reacting a diisocyanate compound such as a diamine, m-tetramethylxylylene diisocyanate, p-tetramethyl xylylene diisocyanate, dimer acid diisocyanate, and a vinyl monomer having a hydroxyl group, a carboxyl group, or an amide group in an equimolar amount are also isocyanic acid. It can be used as an ester compound.

  Examples of the polyfunctional isocyanate having three or more isocyanate groups in one molecule include aromatic polyisocyanate, aliphatic polyisocyanate such as lysine triisocyanate, araliphatic polyisocyanate, and alicyclic polyisocyanate. Examples include the above-mentioned trimethylolpropane adduct of diisocyanate, a buret body reacted with water, and a trimer having an isocyanurate ring. Among these, a trimethylolpropane adduct of diisocyanate and a trimer having an isocyanurate ring are preferable. Furthermore, by using a trimethylolpropane adduct of diisocyanate and a trimer having an isocyanurate ring in combination, migration resistance and flexibility can be improved.

  The blocked isocyanate compound is an isocyanate compound in which an isocyanate group is protected by a blocking agent such as ε-caprolactam and MEK oxime. Specific examples include those in which the isocyanate group of the isocyanate compound is protected with a blocking agent such as ε-caprolactam, MEK oxime, cyclohexanone oxime, pyrazole, and phenol. Among these, MEK oxime is preferable. Among these, the isocyanate compound is preferably a blocked isocyanate compound. It is preferable to use a blocked isocyanate compound because the sheet life is improved.

  The dissociation temperature of the blocking agent of the blocked isocyanate compound is preferably from 120 to 200 ° C, more preferably from 130 to 180 ° C. By setting the dissociation temperature of the blocking agent of the blocked isocyanate compound to 120 ° C. or higher, the curable resin composition did not dissociate at the drying temperature when coated on the transparent substrate, and had excellent patterning properties. A dry resist film is obtained. Further, by setting the dissociation temperature of the blocking agent to 200 ° C. or less, foaming in the cover coat layer can be suppressed during thermal curing when forming the cover coat layer.

  The blocked isocyanate compound preferably has an isocyanate equivalent of 200 to 400 g / eq and 500 to 900 g / eq in combination. Flexibility and migration resistance can be improved by using block isocyanates having different isocyanate equivalents in combination. The isocyanate equivalent referred to in the present invention is a value measured according to JIS K7301.

An epoxy compound is a compound having two or more epoxy groups in one molecule. The properties of the epoxy compound may be liquid or solid.
As the epoxy compound, for example, a glycidyl ether type epoxy compound, a glycidylamine type epoxy compound, a glycidyl ester type epoxy compound, a cyclic aliphatic (alicyclic type) epoxy compound and the like are preferable.

  The molecular weight of the epoxy compound is preferably from 100 to 2000, more preferably from 200 to 1500.

  Examples of the glycidyl ether type epoxy compound include bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, bisphenol AD type epoxy compound, cresol novolak type epoxy compound, phenol novolak type epoxy compound, α-naphthol novolak Epoxy compound, bisphenol A type novolak type epoxy compound, dicyclopentadiene type epoxy compound, tetrabromobisphenol A type epoxy compound, brominated phenol novolak type epoxy compound, tris (glycidyloxyphenyl) methane, tetrakis (glycidyloxyphenyl) ethane And the like.

  Examples of the glycidylamine type epoxy compound include tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidylmethaminophenol, and tetraglycidylmetaxylylenediamine.

  Examples of the glycidyl ester type epoxy compound include diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, and the like.

Examples of the cycloaliphatic (alicyclic) epoxy compound include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate, bis (epoxycyclohexyl) adipate, and the like.
Among them, as the epoxy compound, bisphenol A type epoxy compound, cresol novolak type epoxy compound, phenol novolak type epoxy compound, tris (glycidyloxyphenyl) methane, and tetrakis (glycidyloxyphenyl) ethane are preferable. By using these epoxy compounds, migration resistance and flexibility are further improved.

  The mixing amount of the epoxy compound is preferably 20% by mass or less, more preferably 15% by mass or less, based on the total amount (100% by mass) of the thermosetting agent. By setting the epoxy compound content to 20% by mass or less, the curing reaction in the dry resist film is suppressed and the sheet life is improved, so that the patterning property can be improved.

  The compounding amount of the thermosetting agent is preferably 30 to 150 parts by mass, more preferably 50 to 110 parts by mass, based on 100 parts by mass of the active energy ray-curable resin and the thermosetting resin in total. High migration resistance and flexibility can be obtained by blending 30 to 150 parts by mass of a thermosetting agent with respect to a total of 100 parts by mass of the active energy ray-curable resin and the thermosetting resin.

[Active energy ray polymerization initiator]
Examples of the active energy ray polymerization initiator include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopro An acetophenone-based active energy ray polymerization initiator such as pan-1-one, 1,2-octadion-1- (4- (phenylthio)-, 2- (o-benzoyloxime)], ethanone, 1- [9-ethyl -6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (o- Oxime ester active energy ray polymerization initiators such as cetyl oxime), benzoin active energy ray polymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzyl dimethyl ketal, benzophenone, benzoyl benzoic acid, and benzoyl Benzophenone-based active energy ray polymerization initiators such as methyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenylsulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxan Thioxanthone-based active energy ray polymerization initiators such as 2,4,6-trione, isopropylthioxanthone and 2,4-diisopropylthioxanthone; Rollo-s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- ( (p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s-triazine, 2,4-bis (trichloromethyl) -6-styryl -S-triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4,6-bis (trichloro Tria such as methyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, and 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine Phosphine oxide active energy beam polymerization of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide An initiator, a borate-based active energy ray polymerization initiator, a carbazole-based active energy ray polymerization initiator, an imidazole-based active energy ray polymerization initiator, or the like is used. One of these active energy ray polymerizable compounds can be used alone, or two or more of them can be used in an optional ratio as needed.

  Among them, acylphosphine oxide-based active energy ray polymerization initiators and acetophenone-based active energy ray polymerization initiators are preferred because they have good curability at the bottom of the film and have improved migration resistance. As the acylphosphine oxide-based active energy ray polymerization initiator, specifically, Irgacure TPO (manufactured by BASF), Irgacure 819 (manufactured by BASF), and as the acetophenone-based active energy ray polymerization initiator, specifically, Irgacure 907 (manufactured by BASF), Irgacure 379 (manufactured by BASF), Irgacure 379EG (manufactured by BASF), and the like.

  The active energy ray polymerization initiator is preferably used in an amount of 0.5 to 15 parts by mass based on 100 parts by mass of the solid content of the active energy ray-curable resin.

The active energy ray-curable resin composition further contains α-acyloxyester, acylphosphine oxide, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone, camphorquinone, ethylanthraquinone as a sensitizer. And compounds such as 4,4'-diethylisophthalophenone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone and 4,4'-diethylaminobenzophenone.
The sensitizer can be used in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the active energy ray polymerization initiator.

[Colorant]
The dry resist film contains a coloring agent in order to enhance the light shielding property of the cover coat layer. Examples of the colorant include chromatic pigments such as black, red, green, blue, yellow, purple, cyan, and magenta, and dyes. These may be used alone or may be used as a mixed colorant containing a plurality of them. A black colorant is preferable from the viewpoints of information protection and visibility, and a mixed colorant can obtain black by performing color reduction mixing of a plurality of pigments.

  Examples of the black pigment include carbon black, Ketjen black, carbon nanotube (CNT), perylene black, titanium black, iron black, and aniline black. Among these, from the viewpoint of improving light-shielding properties and migration resistance, perylene black, titanium black, iron black and a mixed colorant are preferable, and perylene black and titanium black are more preferable. Particularly preferred is titanium black.

The colorant preferably has a specific gravity of 2 to 7 g / cm ³ , more preferably 4 to 6 g / cm ³ or more. When the specific gravity of the colorant is 2 to 7 g / cm ³ , the contained colorant is appropriately settled after the curable resin composition is applied to the transparent substrate. Thus, when a dry resist film is formed by drying, and a peelable sheet is attached, the concentration of the colorant is higher on the transparent substrate surface and thinner on the release sheet surface.
Since the dry resist film is attached to the signal circuit side with the surface from which the peelable sheet has been peeled off and forms a cover coat layer, if the colorant component on the signal circuit side can be reduced, the impurity component is reduced and migration resistance is reduced. Can be further improved.

  The colorant preferably has an average primary particle diameter of 20 to 100 nm, more preferably 30 to 90 nm, and still more preferably 40 to 90 nm. By using the coloring agent having the above average primary particle diameter, the cover coat layer formed from the dry resist film has more improved light-shielding properties and flexibility. When the particle shape of the colorant has an average aspect ratio (major axis length / minor axis length) of 1.5 or more, the average primary particle diameter is determined by averaging the major axis length.

  The colorant preferably has a powder resistance of 3 Ω · cm or more, more preferably 5 Ω · cm or more. By setting the powder resistance value of the colorant within the above range, the migration resistance is further improved. The powder resistance value is a resistance value when pressed at a pressing pressure of 2 MPa using a powder resistance measurement system MCP-PD51 and a resistivity meter MCP-T610 manufactured by Mitsubishi Chemical Analytech Co., Ltd.

The specific surface area of the colorant is 10 to 50 m ² / g are preferred, 15~40m ² / g is more preferable. By setting the specific surface area of the coloring agent in the above range, the patterning property is further improved.
The specific surface area can be determined by a BET method using BELSORP-miniII manufactured by Bell Japan Co., Ltd.

  The average primary particle diameter of the colorant can be determined from the average value of about 20 primary particles that can be observed from an image enlarged to about 50,000 to 1,000,000 times by a transmission electron microscope (TEM).

  The following pigments can be used as the mixed colorant. Note that “CI” means a color index (CI).

  Red pigments and magenta pigments include, for example, C.I. I. Pigment Red 7, 14, 41, 48: 1, 48: 2, 48: 3, 48: 4, 57: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 122, 146, 168, 176, 177, 178, 184, 185, 187, 200, 202, 208, 210, 242, 246, 254, 255, 264, 270, 272 and 279.

  Green pigments include, for example, C.I. I. Pigment Green 1, 2, 4, 7, 8, 10, 13, 14, 15, 17, 18, 19, 26, 36, 45, 48, 50, 51, 54, 55, and 58, and the like.

  Blue pigments and cyan pigments include, for example, C.I. I. Pigment Blue 1, 1: 2, 9, 14, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17, 19, 25, 27, 28, 29, 33, 35, 36, 56, 56: 1, 60, 61, 61: 1, 62, 63, 66, 67, 68, 71, 72, 73, 74, 75, 76, 78, 79 and the like.

  Yellow pigments include, for example, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 82,184,185,187,188,193,194,198,199,213 and 214, and the like.

  Examples of the purple pigment include C.I. I. Pigment Violet 1, 1: 1, 2: 2: 2, 3: 1, 3: 3, 5, 5: 1, 14, 15, 16, 19, 23, 25, 27, 29, 31, 32, 37, 39, 42, 44, 47, 49 and 50.

  The coloring agent preferably contains 0.5 to 40% by mass, more preferably 1 to 30% by mass, based on 100% by mass of the dry resist film. By containing the coloring agent in an amount of 0.5 to 40% by mass, it is easy to achieve both high light-shielding properties and resistance to a migration test.

[Inorganic filler]
It is preferable that the curable resin composition further contains an inorganic filler. By including the inorganic filler, the heat-resistant pressure bonding property is further improved. Examples of the inorganic filler include silica, alumina, aluminum hydroxide, magnesium hydroxide, barium sulfate, calcium carbonate, titanium oxide, zinc oxide, antimony trioxide, magnesium oxide, talc, montmorolinite, kaolin, and bentonite. Compounds.
Among these, as the inorganic filler, hydrophobic silica fine particles obtained by reacting a silanol group on the silica surface with a halogenated silane, not only improve the heat-resistant pressure bonding property, but also increase the hydrophobicity of the film and improve the migration resistance. It is preferable from the viewpoint of improvement.

BET specific surface area of the inorganic filler, 50 to 300 m ² / g are preferred. When the content is within the above range, the inorganic filler is uniformly dispersed in the dry resist film, and the heat-resistant pressure-bonding property is improved.

  The average particle diameter (average particle diameter D50) of the inorganic filler is preferably from 0.01 to 10 μm, and more preferably from 0.05 to 8 μm. When the average particle diameter of the inorganic filler is 0.01 to 10 μm, the heat-resistant pressure-bonding property can be further improved.

  The content of the inorganic filler is preferably 0.5 to 40% by mass based on 100% by mass of the solid content of the curable resin composition. That is, it is preferably 0.5 to 40% by mass based on 100% by mass of the resin layer of the dry resist film. More preferably, it is 1 to 30% by mass. If it is 0.5% by mass or more, migration resistance is improved. When the content is 40% by mass or less, the heat-resistant pressure bonding property is improved.

The curable resin composition may contain a monomer, a solvent, a silane coupling agent, an ion scavenger, an antioxidant, a tackifier resin, a plasticizer, an ultraviolet absorber, an antifoaming agent, a leveling regulator, and a filler, if necessary. , Flame retardants and the like.
The curable resin composition can be prepared by adding a solvent, if necessary, to the active energy ray-curable resin, the active energy ray polymerization initiator, and the colorant, followed by mixing and stirring. For the stirring, a known stirring device such as a disper mat or a homogenizer can be used.

<Storage modulus at 85 ° C.>
The dry resist film has a resin layer formed from a curable resin composition containing a coloring agent. The cured product of the resin layer preferably has a storage elastic modulus at 85 ° C. of 1.0E + 06 to 1.0E + 10 Pa. This makes it possible to provide a cover coat layer having high light-shielding properties and excellent patterning properties capable of forming fine openings, and also satisfying the heat-resistant compression resistance, the migration resistance, and the flexibility. Further, 1.0E + 07 to 5.0E + 9Pa is more preferable, and 4.0E + 07 to 1.0E + 9Pa is more preferable. By setting the storage elastic modulus at 85 ° C. to 1.0E + 06 to 1.0E + 10 Pa, migration resistance and flexibility can be imparted.
Note that 1.0E + 06 to 1.0E + ¹⁰ Pa is synonymous with 1.0 × 10 ^{6 to} 1.0 × 10 ¹⁰ Pa and 0.001 to 10 GPa.

  The cured product of the resin layer is obtained by applying the curable resin composition to one surface of the transparent substrate and drying the resulting resin layer to cure the resin layer. That is, the storage elastic modulus at 85 ° C. is a value obtained by using a cured product obtained by curing a resin layer.

Further, when the thickness of the cured product of the resin layer is small, or when the storage elastic modulus at 85 ° C. is difficult to measure due to the flexibility of the resin layer, the cured product is obtained by laminating the resin layers, The storage elastic modulus can be determined by irradiating active energy rays from not only one side but also both sides of the laminate to obtain a sufficiently cured resin layer. Specifically, for example, two samples from which a peelable sheet of a dry resist film with a base material is peeled are prepared, and the exposed resin layer surfaces are vacuum-laminated (heating temperature: 60 ° C., vacuum time: 60 seconds, vacuum ultimate pressure: 2 hPa). , A pressure of 0.4 MPa, and a pressure time of 60 seconds), and then irradiating both sides with an active energy ray from the transparent substrate side so as to have an integrated light amount of 200 to 1000 mJ / cm ² , and then forming one transparent substrate The exposed resin layer surface is developed with a 1% aqueous solution of sodium carbonate at a liquid temperature of 30 ° C. for 60 seconds, and the water in the film is dried and removed using a drying oven at 80 to 100 ° C., and then dried at 140 to 180 ° C. The resin is cured by heating in a box oven, and finally, the transparent substrate on the other side is peeled off, and the cured product of the obtained resin layer can be measured for storage elastic modulus. The storage elastic modulus can be appropriately adjusted according to the type and molecular weight of the resin, the type and content of the thermosetting agent, or the type and content of the colorant.

<Production method of dry resist film>
The dry resist film has a resin layer obtained by applying a curable resin composition to one surface of a transparent base material and drying it. Further, in order to protect the resin layer, it is general to form a laminated structure of a transparent base material / resin layer / peelable sheet in order to protect the resin layer. , A dry resist film with a base material. The dry resist film may further have an intermediate layer such as a cushion layer, an adhesive layer, a light absorbing layer, and a gas barrier layer.

  The resin layer of the dry resist film is formed on a transparent substrate by, for example, a method such as knife coating, die coating, lip coating, roll coating, curtain coating, bar coating, gravure coating, flexo coating, dip coating, spray coating, or spin coating. After applying the liquid curable resin composition dissolved and dispersed in a solvent, the composition can be formed by drying the solvent at a temperature of usually 40 to 120 ° C.

The transparent substrate preferably has a minimum light transmittance at a wavelength of 320 to 700 nm of 50% or more, and more preferably 60% or more. By using a transparent base material having an average light transmittance of 50% or more at a wavelength of 320 to 700 nm, active energy rays reach the dry resist film and are efficiently cured, so that patterning properties are improved.
As the transparent substrate having such a transmittance, a polyethylene terephthalate film or a polyolefin film is suitably used. Note that a release agent may be coated on one or both sides of the polyethylene terephthalate film or the polyolefin film.

  The releasable sheet is a film in which one or both sides of a polyethylene terephthalate film or an OPP film are coated with a release agent, and is a member bonded to protect the dry resist film. The light transmittance of the peelable sheet can be used without any particular limitation.

  The thickness of the resin layer of the dry resist film is preferably from 5 to 100 μm, more preferably from 10 to 70 μm. The dry resist film can be easily handled by forming a resin layer on a transparent base material, further attaching a releasable sheet to another surface, and sandwiching the dry resist film between both surfaces.

《Printed circuit board》
Subsequently, a printed wiring board having a cover coat layer formed using a dry resist film will be described. The printed wiring board includes an electromagnetic wave shielding sheet, a cover coat layer, and a substrate having signal wiring and an insulating base material. By having a cover coat layer formed using a dry resist film, a printed wiring board with an electromagnetic wave shielding sheet having excellent ion migration resistance, flexibility and light shielding properties can be obtained.

<Electromagnetic wave shield sheet>
The electromagnetic wave shielding sheet includes a conductive layer and an insulating layer, at least one of which contains phosphorus (P). By including phosphorus (P) in the electromagnetic wave shielding sheet, flame retardancy can be improved. Examples of phosphorus (P) include phosphorous esters, red phosphorus, ammonium phosphate, phosphazene compounds, phosphinates, and phosphorus-based difficulties such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative. And the like. The phosphorus (P) element is preferably from 1 to 10%, more preferably from 2 to 7%, based on the total solid content of the layer containing phosphorus (P).

[Conductive layer]
The conductive layer of the electromagnetic wave shielding sheet is a layer that shields noise such as electromagnetic waves and is mainly attached to the cover coat layer of the FPC. The conductive layer has two modes, a first mode of a conductive layer formed from a conductive adhesive and a second mode having a metal layer and a conductive layer formed from a conductive adhesive. The conductive adhesive layer, gold, platinum, silver, conductive fine particles made of a conductive metal such as nickel and nickel and alloys thereof, and the active energy ray resin composition forming the dry resist film described, It is formed by coating a conductive resin composition obtained by mixing a thermosetting resin and a thermosetting agent. As the metal layer, for example, a conductive metal vapor-deposited film such as aluminum, copper, silver, or gold having a thickness of 0.005 to 10 μm, a metal foil, or the like is used.

[Insulating layer]
The insulating layer can be formed using an insulating resin composition. The insulating layer can be formed by coating a thermosetting resin and an insulating resin composition containing a thermosetting agent in the same manner as the conductive adhesive. Further, a film obtained by molding an insulating resin such as polyester, polycarbonate, polyimide, and polyphenylene sulfide can also be used.

  The electromagnetic wave shielding sheet has a thermosetting resin and a thermosetting agent contained in the conductive layer in an uncured state, and can be cured by a hot press together with the cover coat layer to obtain a desired adhesive strength. The uncured state includes a semi-cured state in which a part of the thermosetting agent is cured.

<Substrate>
The substrate has a signal wiring and an insulating base. Examples of the signal wiring include a ground wiring for grounding and a wiring circuit for sending an electric signal to an electronic component. The wiring is generally formed by etching a copper foil. The insulating base material is preferably a flexible plastic such as polyester, polycarbonate, polyimide, polyphenylene sulfide, or liquid crystal polymer, and more preferably polyimide.

<Production method of printed wiring board with electromagnetic wave shield>
A method for manufacturing a printed wiring board with an electromagnetic wave shielding sheet according to the present invention will be described. The printed wiring board with an electromagnetic wave shielding sheet of the present invention includes a step of forming signal wiring on an insulating base material (step A), a step of laminating a dry resist film on the signal wiring (step B), and a resin layer of the dry resist film. To form a cover coat layer having openings by exposing and thermally curing after development (step C), and laminating an electromagnetic wave shielding sheet on the cover coat layer and hot pressing (step D). Can be. Hereinafter, each step will be specifically described.

(Step A; signal wiring forming step)
First, ground wiring for grounding by etching a copper foil on an insulating substrate and signal wiring including a wiring circuit for sending an electric signal to an electronic component are formed.

(Step B: Dry resist film laminating step)
Next, the releasable sheet of the dry resist film sandwiched between the transparent substrate and the releasable sheet on both sides is peeled off, and the exposed resin layer surface is bonded by a laminator so as to cover the signal wiring on the insulating substrate.

(Step C-1; cover coat layer forming step)
When the dry resist film contains an active energy ray-curable resin, the active energy ray is irradiated from the upper surface of the transparent base material through a photomask formed into a desired pattern, and the resin layer of the dry resist film is exposed to the active energy ray. Let it cure.

As an active energy ray for curing the resin layer of the dry resist film, an electron beam, an ultraviolet ray, or a light ray having a wavelength of 350 to 500 nm can be used. As a source of the electron beam to be irradiated, a thermionic emission gun, a field emission gun, or the like can be used. Further, as the ultraviolet ray and a 350-500 nm radiation source (light source), for example, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a gallium lamp, a xenon lamp, a carbon arc lamp, or the like can be used. Specifically, an ultra-high pressure mercury lamp, a xenon mercury lamp, and a metal halide lamp are often used from the viewpoint of a point light source and luminance stability. The active energy dose to be irradiated, can be set appropriately in the range of 5~2000mJ / cm ^2, it is preferably in the range on the easy of 50~1000mJ / cm ² management process. It is also possible to use these active energy rays in combination with heat by infrared rays, far infrared rays, hot air, high-frequency heating, or the like.

Thereafter, the transparent substrate is peeled off, and the non-irradiated portion is washed away by developing with an alkaline aqueous solution, and an opening is formed on the ground wiring or in a necessary portion.
A hole is usually formed in a coverlay film using a drill to form an opening having a diameter of 2 to 5 mm. However, by using a dry resist film in the present invention, the diameter of the opening is reduced to 0 mm. It is possible to form a cover coat layer having an opening of 0.05 to 1 mm and having no tapered development residue. By setting the opening diameter to 0.05 to 1 mm, for example, the ground wiring area can be significantly reduced, so that the FPC can be shortened.

  In the development, an aqueous solution of sodium carbonate, sodium hydroxide or the like is used as an alkali developing solution, and an organic alkali such as dimethylbenzylamine or triethanolamine can also be used. Further, an antifoaming agent or a surfactant can be added to the developer.

  As a developing treatment method, a shower developing method, a spray developing method, a dip (immersion) developing method, a paddle (liquid puddle) developing method, or the like can be applied.

  After washing the developing solution with water, it is heated at 80 ° C. to 110 ° C. for 2 minutes to 10 minutes to remove unnecessary water, and then heated at 150 ° C. to 180 ° C. for 30 minutes to 2 hours, and cured by heat to cover. Form a coat layer. An active energy ray can be irradiated as needed even after the thermosetting.

(Step C-2; cover coat layer forming step)
When the dry resist film does not contain an active energy ray-curable resin, the film is heated at 150 ° C. to 180 ° C. for 1 minute to 2 hours, thermally cured, and then the transparent substrate is peeled off to form a cover coat layer. At that time, if necessary, a press at a pressure of about 1 to 3 MPa can be used in combination. In addition, as a method of forming an opening on a ground wiring or a necessary portion, a die cutting process, a router process, a laser cutter, and the like can be cited. From the viewpoint of reducing the size of the opening, a router process and a laser cutter are preferable. By setting the opening diameter to 0.05 to 1 mm, for example, the ground wiring area can be significantly reduced, so that the FPC can be shortened. The step of forming the opening may be any of before and after applying the dry resist film to the substrate, and when forming the thermosetting cover coat layer, from the viewpoint that the shape at the time of forming the opening is easily maintained. After heat curing, it is more preferable.

(Step D; hot press step)
Next, an electromagnetic wave shielding sheet punched into a predetermined size is laminated on a part or the entire surface of the cover coat layer, and is temporarily attached. Thereafter, the conductive layer of the electromagnetic wave shielding sheet is thermally cured and bonded by hot pressing. At this time, the conductive adhesive layer flows into the opening of the cover coat layer formed on the ground wiring and hardens, so that the conductive adhesive layer is electrically connected to the ground, so that the shielding property is further improved.

  The heat pressing of the electromagnetic wave shielding sheet and the wiring board is generally performed at a temperature of about 150 to 190 ° C., a pressure of about 1 to 3 MPa, and a time of about 1 to 60 minutes. The thermosetting resin reacts with the thermosetting agent by hot pressing. In addition, post-curing may be performed at 150 to 190 ° C. for 30 to 90 minutes after hot pressing in order to promote curing. The electromagnetic wave shielding sheet may be referred to as an electromagnetic wave shielding layer after hot pressing.

  In the obtained printed wiring board with an electromagnetic shielding sheet, the printed wiring board with an electromagnetic shielding sheet is cut to expose the cross section at the shortest distance between the phosphorus (P) -containing layer of the electromagnetic shielding sheet and the signal wiring. The cross section can be measured by observing the cross section with a SEM from a vertical direction.

As a method of cutting the printed wiring board with the electromagnetic wave shielding sheet and exposing the cross section, there are known methods such as a cleaving method, a mechanical polishing method, a microtome method, and a FIB (focused ion beam) method. However, when different materials such as a printed wiring board with an electromagnetic wave shielding sheet are included, different shapes such as peeling of different interfaces and deformation of voids, so-called artifacts, are generated during cross-sectional fabrication. A cross-sectional structure may not be obtained. On the other hand, the CP (cross section polisher) method is a cross-section preparation method using a broad Ar (argon) ion beam, and a metal, semiconductor, ceramic, and a composite material thereof can be used to form a smooth and distortion-free sample cross section. be able to. That is, in the present invention, the method of cutting the metal layer is preferably the CP method.
The shortest distance between the layer containing phosphorus (P) of the electromagnetic wave shielding sheet and the signal wiring is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more from the viewpoint of migration resistance. From the viewpoint of flexibility, the thickness is preferably 80 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less.

  The shortest distance between the phosphorus (P) -containing layer of the electromagnetic wave shielding sheet and the signal wiring is appropriately determined according to the thickness of the cover coat layer, which layer of the electromagnetic wave shielding sheet contains phosphorus (P), and the like. It is possible to adjust.

  The printed wiring board is preferably provided in an electronic device such as a notebook PC, a mobile phone, a smartphone, and a tablet terminal, in addition to a liquid crystal display and a touch panel.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to only the following Examples. The method for synthesizing the active energy ray-curable resin and the like used in the examples is shown below.

[Active energy ray curable resin 1]
In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, an inlet tube, and a thermometer, bisphenol A type epoxy having an epoxy equivalent of 650, a softening point of 81.1 ° C, and a melt viscosity (150 ° C) of 12.5 poise After 371 parts of resin, 925 parts of epichlorohydrin and 463 parts of dimethyl sulfoxide were charged and uniformly dissolved, 52.8 parts of a 98.5% aqueous sodium hydroxide solution was added at 70 ° C. with stirring over 100 minutes. After the addition, the reaction was further performed at 70 ° C. for 3 hours. Next, most of the excess unreacted epichlorohydrin and dimethyl sulfoxide are distilled off under reduced pressure, the reaction product containing the by-product salt and dimethyl sulfoxide is dissolved in 750 parts of methyl isobutyl ketone, and 10 parts of a 30% aqueous sodium hydroxide solution is further dissolved. And reacted at 70 ° C. for 1 hour. After the completion of the reaction, the resultant was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone is distilled and recovered from the oil layer, and an epoxy resin having an epoxy equivalent of 287, a hydrolyzable chlorine content of 0.07%, a softening point of 64.2 ° C, and a melt viscosity (150 ° C) of 7.1 poise. 340 parts were obtained.

  In a four-necked flask equipped with another stirrer, a reflux condenser, a nitrogen inlet tube, an inlet tube, and a thermometer, 287 parts of this epoxy resin was charged, and further 72 parts of acrylic acid, 0.3 part of methylhydroquinone, and 194 parts of cyclohexanone. The mixture was heated to 90 ° C. and stirred to dissolve the reaction mixture. Then, the reaction was carried out at 100 ° C. for about 48 hours in the presence of oxygen to obtain a reaction product having an acid value of 1 mgKOH / g. Next, 78 parts of succinic anhydride and 42 parts of cyclohexanone were added thereto and reacted at 95 ° C. for about 6 hours. Cyclohexanone was added to this solution to adjust the solid content to 50.0%, to obtain an active energy ray-curable resin 1 solution. The active energy ray-curable resin 1 is a carboxyl group-containing photosensitive resin whose main skeleton is a bisphenol A type epoxy resin, has an ethylenically unsaturated group equivalent of 450 g / eq, a polystyrene equivalent mass average molecular weight of 7400, and a molecular weight distribution. 2.23, the acid value of the resin solids as measured was 100 mgKOH / g.

[Active energy ray-curable resin 2]
In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, an inlet tube, and a thermometer, 64.8 parts of bisphenol A and 57.1 parts of YD8125 (a bisphenol A type epoxy compound manufactured by Nippon Steel Chemical Co., Ltd.) , EX861 (manufactured by Nagase ChemteX Corporation: polyethylene glycol diglycidyl ether), 128.1 parts, N, N-dimethylbenzylamine as a catalyst, 1.25 parts, and toluene as a solvent, 250 parts were charged and stirred under a nitrogen stream. The temperature was raised to 110 ° C. and the reaction was carried out for 12 hours to obtain a hydroxyl group-containing resin. Next, 54.6 parts of RIKACID SA (manufactured by Shin Nippon Rika Co., Ltd .: succinic anhydride) was added as an acid anhydride, and the mixture was reacted at 110 ° C. for 4 hours. After confirming that the absorption of the acid anhydride group had disappeared by FT-IR measurement, the mixture was cooled to room temperature. Next, in this flask, the nitrogen from the nitrogen inlet tube was stopped, the air was switched to the introduction of dry air, and 26.0 parts of GMA (manufactured by NOF CORPORATION: glycidyl methacrylate) was stirred while hydroquinone 0.165 was used as a polymerization inhibitor. Then, the mixture was reacted at 80 ° C. for 8 hours. After completion of the reaction, methyl ethyl ketone was added to this solution to adjust the solid content to 50.0%, to obtain an active energy ray-curable resin 2 solution. The active energy ray-curable resin 2 is a hydroxyl group-containing photosensitive resin (A-1), has an ethylenically unsaturated group equivalent of 1803 g / eq, a mass average molecular weight in terms of polystyrene of 23500, and an acid content of a resin solid measured by actual measurement. The value was 63 mg KOH / g.

[Active energy ray-curable resin 3]
In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, an inlet tube, and a thermometer, 60.8 parts of bisphenol A and 43.4 parts of YD8125 (a bisphenol A type epoxy compound manufactured by Nippon Steel Chemical Co., Ltd.) EX861 (manufactured by Nagase ChemteX Corporation: polyethylene glycol diglycidyl ether) (145.8 parts), N, N-dimethylbenzylamine (1.25 parts) as a catalyst, and toluene (250 parts) as a solvent were charged and stirred under a nitrogen stream. The temperature was raised to 110 ° C. and the reaction was carried out for 12 hours to obtain a hydroxyl group-containing resin. Next, 49.8 parts of Ricacid SA (manufactured by Shin Nippon Rika Co., Ltd .: succinic anhydride) was added as an acid anhydride, and the mixture was reacted at 110 ° C. for 4 hours. After confirming that the absorption of the acid anhydride group had disappeared by FT-IR measurement, the mixture was cooled to room temperature. Next, in this flask, the nitrogen from the nitrogen inlet tube was stopped, and the flow was switched to the introduction of dry air. With stirring, 41.1 parts of GMA (glycidyl methacrylate, manufactured by NOF CORPORATION) and 0.17 of hydroquinone as a polymerization inhibitor were used. Then, the mixture was reacted at 80 ° C. for 8 hours. After the completion of the reaction, 26.0 parts of Ricacid SA (manufactured by Nippon Rika Co., Ltd .: succinic anhydride) was added as an acid anhydride to the flask in which dry air had been introduced, and the reaction was carried out at 80 ° C. for 4 hours. After confirming that the absorption of the acid anhydride group had disappeared by FT-IR measurement, the mixture was cooled to room temperature. Methyl ethyl ketone was added to this solution to adjust the solid content to 50.0%, to obtain an active energy ray-curable resin 3 solution. The active energy ray-curable resin 3 is a carboxyl group-containing photosensitive resin (A-2), the equivalent weight of an ethylenically unsaturated group is 1269 g / eq, the mass average molecular weight in terms of polystyrene is 20200, and the acid content of the resin solid is measured. The value was 73 mg KOH / g.

[Thermosetting resin]
In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, an inlet tube, and a thermometer, a polycarbonate diol (UM90 (3/1): 1,4-cyclohexanedimethanol / 1, manufactured by Ube Industries, Ltd.) was added. 274.8 parts of 6-hexanediol = 3/1 copolymerized polycarbonate diol), 39.2 parts of isophorone diisocyanate, and 300 parts of toluene as a solvent are charged, and the mixture is heated to 60 ° C. while stirring under a nitrogen stream, and uniformly dissolved. I let it. Subsequently, 0.1 part of dibutyltin dilaurate was charged into the flask, heated to 110 ° C., and reacted for 3 hours. Then, after cooling to 40 ° C., 37.6 parts of tetrahydrophthalic anhydride (Likacid TH: manufactured by Shin Nippon Rika Co., Ltd.) was added, and the temperature was raised to 110 ° C. and reacted for 4 hours. Subsequently, after cooling to 40 ° C., 42.7 parts of a biphenyl type epoxy resin (YX4000H: manufactured by Mitsubishi Chemical Corporation: epoxy equivalent = 192 g / eq) was added, the temperature was raised to 110 ° C., and the reaction was carried out for 12 hours. After cooling to 40 ° C., 32.5 parts of tetrahydrophthalic anhydride was added and reacted at 110 ° C. for 3 hours. After cooling to 40 ° C., the solid content was adjusted to 60% with toluene to obtain a carboxyl group-containing modified urethane ester resin (A) solution. The obtained carboxyl group-containing modified urethane ester resin (A) had a mass average molecular weight of 37270 and an acid value of the resin solids of 30.2 mgKOH / g.

[Surface treatment flame retardant]
To 800 ml of an ethanol solution (concentration: 0.4%) of tetraethyl orthosilicate (hereinafter also referred to as TEOS), 10 g of aluminum phosphinate having a D95 particle size of 5 μm determined by the method described later was added, and the pH was adjusted with concentrated NH ₃ water. After adjusting to 12, the mixture was stirred for 3 hours, filtered, and washed with ethanol to obtain a surface-treated flame retardant having silica adhered to the surface of aluminum phosphinate. The amount of silica was determined by inductively coupled plasma (ICP) emission spectroscopy, and was 0.01 parts with respect to 100 parts of aluminum phosphinate.

<Method for measuring D95 particle size>
D95 indicates a particle size when the volume integrated value of 95% is included in the particle size distribution of the flame retardant. The particle size of the flame retardant was measured using Microtrac MT3000EX (manufactured by Nikkiso Co., Ltd.). A flame retardant was dispersed in a 1% aqueous solution of sodium dodecylbenzenesulfonate while stirring to prepare a measurement sample. The measurement was performed by inputting the refractive index of water and the refractive index of the flame retardant, and adjusting the sample concentration so that the measurement time was 20 seconds and the Signal Level was within the green range.

  Table 1 shows the physical properties of the active energy ray-curable resins 1 to 3. Table 2 shows the physical properties of Colorants 1 and 2.

Active energy ray polymerization initiator: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propane) "Irgacure 907" Sensitizer manufactured by BASF: 2,4-diethylthioxanthone "DETX" -S "Nippon Kayaku Co., Ltd. thermosetting agent 1: HDI nullate type MEK oxime-blocked isocyanate compound" Duranate MF-B60X "(isocyanate equivalent = 525 g / eq) Asahi Kasei Chemicals Co., Ltd. thermosetting agent 2: HDI adduct type MEK oxime block Isocyanate compound “MYTEC BLE-29” (isocyanate equivalent = 646 g / eq) Thermosetting agent 3: bisphenol A type epoxy compound manufactured by Mitsubishi Chemical Corporation, “JER828” (epoxy equivalent = 189 g / eq) inorganic filler manufactured by Mitsubishi Chemical Corporation: Hydrophobic silica "" AEROSIL R8 12 (primary average particle size 7 nm) "manufactured by Nippon Aerosil Co., Ltd.

<Preparation of electromagnetic wave shielding sheet>
100 parts of the above-prepared thermosetting resin and 550 conductive fine particles (dendritic particles D50 using copper for the core and silver for the coating layer, average particle size of D50 = 11.0 μm, manufactured by Fukuda Metal Foil & Powder Co., Ltd.) Parts, 15 parts of "Denacol EX212" (bifunctional epoxy compound, epoxy equivalent = 151 g / eq, manufactured by Nagase ChemteX Corporation) as a thermosetting agent, and 2 parts of "Chemite PZ-33" (aziridine compound, manufactured by Nippon Shokubai Co., Ltd.) 2.0 parts, and 23 parts of TEOS surface-treated aluminum phosphinate (D95 average particle diameter = 5 μm) were charged into a container, and a mixed solvent of toluene: isopropyl alcohol (mass ratio 2: 1) was used so that the concentration of nonvolatile components became 40% by mass. Was added and stirred with a disper for 10 minutes to obtain a conductive resin composition. Next, the conductive resin composition is applied on a peelable sheet using a bar coater so that the dry thickness becomes 10 μm, and further dried for 2 minutes in an electric oven at 100 ° C. As a result, a conductive layer having a phosphorus (P) concentration of 4% was obtained.

  Separately, 100 parts of the thermosetting resin produced above, 15 parts of "Denacol EX212" (bifunctional epoxy compound, epoxy equivalent = 151 g / eq, manufactured by Nagase ChemteX Corporation) as a thermosetting agent, and "Chemite PZ-33" 2.0 parts of an aziridine compound (manufactured by Nippon Shokubai Co., Ltd.) and 23 parts of TEOS surface-treated aluminum phosphinate (D95 average particle size = 5 μm) were charged into a container, and toluene and isopropyl were added so that the non-volatile content concentration became 40% by mass. An insulating resin composition was obtained by adding a mixed solvent of alcohol (mass ratio 2: 1) and stirring with a disper for 10 minutes. This insulating resin composition is applied to a peelable sheet using a bar coater to a dry thickness of 15 μm, and further dried in an electric oven at 100 ° C. for 3 minutes to obtain an insulating resin having a phosphorus (P) concentration of 4%. Layer obtained. Further, an electromagnetic wave shielding sheet was obtained by laminating the conductive layer and the insulating layer with a laminator. According to the embodiment, when a metal thin film is laminated between the conductive layer and the insulating layer, the metal thin film having silver deposited on the conductive layer to have a thickness of 0.1 μm and the insulating layer are laminated with a laminator. Then, an electromagnetic wave shielding sheet can be obtained. When the thicknesses of the conductive layer and the insulating layer were changed, the thicknesses of the conductive resin composition and the insulating resin composition applied were changed. When the concentration of phosphorus (P) contained in the conductive layer and the insulating layer is changed, the concentration of phosphorus (P) in the conductive resin composition and the insulating resin composition is adjusted so that the phosphorus (P) concentration in Table 3 is obtained. The amount of the TEOS surface treated aluminum phosphinate was adjusted to produce an electromagnetic wave shielding sheet.

[Example 1]
100 parts of the active energy ray-curable resin 1, 1.5 parts of hydrophobic silica, and 3 parts of a black colorant are charged into a container, and methyl ethyl ketone: methyl polyglycol = 1: 1 (mass) so that the solid content becomes 50%. Ratio) A mixed solvent was added and mixed so as to be uniform. This was dispersed using a horizontal sand mill DYNO-MILL (manufactured by Shinmaru Enterprise Co., Ltd.) until the particle diameter by a grind gauge became less than 10 μm. Next, 4 parts of the active energy ray polymerization initiator, 0.5 part of the sensitizer, 2 parts of the heat curing agent 1 and 2 parts of the heat curing agent 2 were added to 100 parts of the active energy ray-curable resin 1 of the dispersion coating liquid. Was added and uniformly mixed to obtain an active energy ray-curable resin composition.

  The obtained active energy ray-curable resin composition is coated with a transparent substrate (polyethylene terephthalate (PET) film (emblet S25, thickness 25 μm, 320 to 320 μm) so that the thickness after drying using a doctor blade is 38 μm. The minimum light transmittance at 700 nm was 60% or more, manufactured by Unitika Ltd.)), and the mixture was dried at 100 ° C. for 5 minutes, and then cooled to room temperature to form a resin layer. The obtained resin layer is further peeled off with a release sheet (polyethylene terephthalate (PET) film coated with a release agent (PET75-AL5, thickness 75 μm, minimum light transmittance of 320 to 700 nm of 60% or more, manufactured by Lintec Corporation)) To obtain a dry resist film having a resin layer sandwiched between a transparent substrate and a peelable sheet.

The peelable sheet of the obtained dry resist film was peeled off, and the exposed resin layer surface was placed on the signal wiring side of the insulating base material on which the signal wiring was formed, using a vacuum laminator (Nichigo Morton small pressurized vacuum laminator V-130). Pasted. The vacuum lamination conditions were a heating temperature of 60 ° C., a vacuum time of 60 seconds, an ultimate vacuum pressure of 2 hPa, a pressure of 0.4 MPa, and a pressure time of 60 seconds. Then, an active energy ray was irradiated from the transparent substrate side of the obtained laminate. The irradiation conditions of the active energy ray were as follows. Contact exposure method using Mylar film (125 μm PET film), use of short arc UV lamp, integrated exposure amount 500 mJ / cm ² .
Next, one of the transparent substrates was peeled off, and the exposed resin layer surface was developed with a 1% aqueous solution of sodium carbonate at a liquid temperature of 30 ° C. for 60 seconds, washed with water, and dried in a box oven at 100 ° C. for 2 minutes. Heat curing was performed in a box oven at 160 ° C. for 1 hour to obtain a wiring board with a cover coat layer 4.

  Further, the conductive layer side of the obtained electromagnetic wave shielding sheet and the cover coat layer 4 are bonded to each other, and the thermosetting resin is cured by hot pressing at 150 ° C., 2.0 MPa, for 30 minutes. A printed wiring board was obtained.

[Examples 2 to 18, Example 20, Comparative Examples 1 to 3]
Except having changed as described in Table 3, it carried out similarly to Example 1 and obtained the printed wiring board with an electromagnetic shielding sheet of Examples 2-18, Example 20, and Comparative Examples 1-3, respectively. However, in Examples 2 to 5, 15 to 18, and 20 and Comparative Examples 2 to 3, the active energy ray-curable resin composition is applied so that the thickness of the resin layer becomes a numerical value shown in Table 3. The film thickness was changed.
In the table, unless otherwise specified, numerical values indicate parts, and blank columns indicate that no compounding was performed.

[Example 19]
100 parts of thermosetting resin, 1.5 parts of hydrophobic silica, and 3 parts of black colorant are charged in a container, and methyl ethyl ketone: methyl polyglycol = 1: 1 (mass ratio) is mixed so that the solid content becomes 50%. The solvent was added and mixed until uniform. This was dispersed using a horizontal sand mill DYNO-MILL (manufactured by Shinmaru Enterprise Co., Ltd.) until the particle diameter by a grind gauge became less than 10 μm. Next, a thermosetting resin composition was obtained by adding 2 parts of the thermosetting agent 1 and 40 parts of the thermosetting agent 2 to 100 parts of the thermosetting resin and uniformly mixing them.

  The obtained thermosetting resin composition is uniformly coated on a transparent substrate (polyethylene terephthalate (PET) film) having a thickness of 25 μm peeled off on both sides so that the thickness after drying using a doctor blade is 70 μm. After coating and drying at 100 ° C. for 5 minutes, the mixture was cooled to room temperature to form a resin layer. Further, the obtained resin layer is bonded to a 75 μm-thick release sheet (polyethylene terephthalate (PET) film coated with a light release agent) to have a transparent substrate and a resin layer sandwiched between the release sheets. A dry resist film was obtained.

  The peelable sheet of the obtained dry resist film was peeled off, and the exposed resin layer surface was placed on the signal wiring side of the insulating base material on which the signal wiring was formed, using a vacuum laminator (Nichigo Morton small pressurized vacuum laminator V-130). Pasted. The vacuum lamination conditions were a heating temperature of 60 ° C., a vacuum time of 60 seconds, an ultimate vacuum pressure of 2 hPa, a pressure of 0.4 MPa, and a pressure time of 60 seconds. Next, the transparent substrate was peeled off, and heat-cured in a box oven at 160 ° C. for 1 hour to obtain a wiring board with a cover coat layer 4.

  Further, the conductive layer side of the obtained electromagnetic wave shielding sheet and the cover coat layer 4 are bonded to each other, and the thermosetting resin is cured by hot pressing at 150 ° C., 2.0 MPa, for 30 minutes. A printed wiring board was obtained.

[Example 21]
100 parts of the active energy ray-curable resin 1, 1.5 parts of the hydrophobic silica, and 3 parts of the black colorant were charged into a container, preliminarily mixed, and then sufficiently kneaded with a three-roll mill. Next, 4 parts of the active energy ray polymerization initiator, 0.5 part of the sensitizer, 2 parts of the heat curing agent 1 and 2 parts of the heat curing agent 2 were added to 100 parts of the active energy ray-curable resin 1 of the dispersion coating liquid. Was added, and cellosolve acetate was further added as a solvent so that the solid content became 70%, followed by mixing with a small planetary mixer to obtain an active energy ray-curable resin composition.

  The obtained active energy ray-curable resin composition is uniformly applied to the same place where the dry film is attached by a screen printing method using a polyester screen plate having a mesh size selected so that the film thickness after drying is 38 μm. After coating, the resin was dried in a hot air oven at 80 ° C. for 30 minutes to form a resin layer. Thereafter, adjustment was performed under the same conditions as for the dry resist film to obtain a wiring board with a cover coat layer 4 and a printed wiring board with an electromagnetic wave shielding sheet.

The following physical properties were evaluated for the obtained printed wiring board with the electromagnetic wave shielding sheet.
<Storage modulus, glass transition temperature (Tg)>
The storage elastic modulus and Tg of the cured product of the resin layer of the dry resist film were determined by the following methods. Two samples in which the peelable sheet was peeled from the dry resist film with the base material were prepared, and the exposed resin layer surfaces were bonded together with a vacuum laminator (Nichigo Morton's small pressure type vacuum laminator V-130). The vacuum lamination conditions were a heating temperature of 60 ° C., a vacuum time of 60 seconds, an ultimate vacuum pressure of 2 hPa, a pressure of 0.4 MPa, and a pressure time of 60 seconds. Then, in the case of a dry resist film produced using the active energy ray-curable resin composition, both sides of the obtained sample were irradiated with active energy rays. The irradiation conditions of the active energy ray were as follows. Contact exposure method using Mylar film (125 μm PET film), use of short arc UV lamp, integrated exposure amount 500 mJ / cm ² . Next, one of the transparent substrates was peeled off, and the exposed resin layer surface was developed with a 1% aqueous solution of sodium carbonate at a liquid temperature of 30 ° C. for 60 seconds, washed with water, and dried in a box oven at 100 ° C. for 2 minutes. Heat cured in a box oven at 160 ° C. for 1 hour, cut into a size of 5 mm wide × 30 mm long, peel off the other transparent substrate, and obtain a measurement sample for the cured product of the resin layer of the dry resist film Was. In the case of a dry resist film produced using a thermosetting resin composition, it is heat-cured in a box oven at 160 ° C. for 1 hour, cut into a size of 5 mm in width × 30 mm in length, and the other transparent substrate Was peeled off to obtain a measurement sample of a cured product of the resin layer of the dry resist film.
Next, using a dynamic elastic modulus measurement device DVA-200 (manufactured by IT Measurement Control Co., Ltd.), the deformation mode is “tensile”, the frequency is 10 Hz, the heating rate is 10 ° C./min, the measurement temperature range is 30 to The measurement was performed at 300 ° C., and the storage elastic modulus and Tg at 85 ° C. were determined.

<Migration test>
The migration test will be described with reference to FIG. As shown in the plan view of FIG. 1 (1), a laminate of a copper foil having a thickness of 12 μm and a polyimide film having a thickness of 25 μm was etched to form a line / space on the polyimide film 1 of 0.05 mm / 0.05 mm. Then, a comb-shaped signal wire 2 for a cathode provided with a cathode electrode connection point 2 'and a comb-shaped signal wire 3 for an anode electrode provided with an anode electrode connection point 3' were formed.
Next, the peelable sheet is peeled off from the dry resist film with the base material, and as shown in the plan view of FIG. 1 (2), the comb-shaped signal wiring 2 for the cathode electrode and the comb-shaped signal wiring 3 for the anode electrode are covered. The surface of the resin layer was overlapped to such an extent that the vicinity of the connection point 2 'and the vicinity of the anode electrode connection point 3' were exposed, and the laminate was vacuum-laminated to bond the dry resist film to the laminate. The vacuum lamination conditions were a heating temperature of 60 ° C., a vacuum time of 60 seconds, an ultimate vacuum pressure of 2 hPa, a pressure of 0.4 MPa, and a pressure time of 60 seconds. Further, in the case of a dry resist film produced using an active energy ray-curable resin composition, a contact exposure method using a mylar film (125 μm PET film) from the transparent substrate side of the dry resist film with a substrate, short-circuiting, Exposure was performed using an arc UV lamp so that the integrated exposure amount was 500 mJ / cm ² . Next, the PET mylar sheet and the transparent substrate were peeled off, and development was performed with a developing machine for 60 seconds (developer: 1% aqueous sodium carbonate solution, liquid temperature 30 ° C., spray pressure 0.2 MPa). After development, it is washed with water, dried in a box oven at 100 ° C. for 2 minutes, and then thermally cured (post-cured) for 1 hour with a 160 ° C. hot air dryer to form a wiring board with a cover coat layer 4. I got In the case of a dry resist film produced using a thermosetting resin composition, the resin layer of the dry resist film is heat-cured (post-cured) for 1 hour with a hot air dryer at 160 ° C., and then the transparent substrate is peeled off. Was used as a wiring board with a cover coat layer 4.
Further, the peelable sheet was peeled off from the conductive layer side of the obtained electromagnetic wave shielding sheet, and the exposed conductive layer surface was bonded on the cover coat layer 4 to laminate a sample as shown in the plan view of FIG. Obtained. In the obtained sample, the conductive layer 5b is electrically connected to the comb-shaped signal wiring 2 for the cathode electrode as described in the AA 'cross-sectional view of the sample shown in FIG.

  The thermosetting resin was cured by hot pressing the obtained sample at 150 ° C., 2.0 MPa, and 30 minutes. Next, the sample was placed in an atmosphere of 85 ° C.-85% RH (relative humidity), an anode electrode was connected to the anode electrode connection point 3 ′, a cathode electrode was connected to the cathode electrode connection point 2 ′, and a voltage of 50 V was applied. The application was continued for 500 hours. Then, the change of the resistance value until 500 hours passed was continuously measured. The “leak touch” described below means that there is dielectric breakdown due to a short circuit, and the resistance instantaneously decreases and current flows. If there is no leak touch, the insulation does not decrease. The evaluation criteria are as follows.

◎: The resistance value after 500 hours has passed is 1 × 10 ⁷ Ω or more, and there is no leak touch. Very good ：: The resistance value after 500 hours passed was 1 × 10 ⁷ Ω or more, and there was one leak touch. Good: The resistance value after 500 hours passed was 1 × 10 ⁷ Ω or more, and there were two leak touches. No problem in practical use.
×: The resistance value after 500 hours has passed is less than 1 × 10 ⁷ Ω, or
The resistance value after 500 hours has passed is 1 × 10 ⁷ Ω or more, and there are three or more leak touches. Not practical.

<Heat resistant crimp resistance>
The peelable sheet of the dry resist film with the substrate was peeled off, and vacuum-laminated with a polyimide film ("Kapton 200EN" manufactured by Du Pont-Toray Co., Ltd.). Thereafter, in the case of a dry resist film produced using the active energy ray-curable resin composition, exposure, development, and post-curing are performed in the same procedure as the migration test, and a polyimide film with a cover coat layer (sample a ) Was prepared. In the case of a dry resist film produced using the thermosetting resin composition, the transparent substrate was peeled off after post-curing without performing exposure and development, thereby producing a polyimide film with a cover coat layer (sample a). Next, an electromagnetic wave shielding sheet was attached to the surface of the cover coat layer of the sample a in the same procedure as in the migration test, and hot-pressed to produce a laminate (sample b) composed of an electromagnetic wave shielding film / cover coat layer / polyimide film.
Samples a and b were each cut from the polyimide film side by ion beam irradiation using a cross section polisher (SM-09010, manufactured by JEOL Ltd.) to form a cross section of the cover coat layer. Using a laser microscope VK-X100 (manufactured by Keyence Corporation) and VK-H1XV (manufactured by Keyence Corporation) as an observation application, the thicknesses of the cover coat layers of the samples a and b were measured, and the rate of change of the thickness was determined from the following equation. Was.

Thickness change rate = 100− (cover coat layer thickness of sample b / cover coat layer thickness of sample a × 100)

The heat resistance and pressure resistance were evaluated according to the following evaluation criteria by the thickness change rate.

A: Less than 2%. Very good.
：: 2% or more and less than 4%. Good.
Δ: 4% or more and less than 5%. No problem in practical use.
X: 5% or more. Not practical.

<Flexibility>
The peelable sheet of the dry resist film with the substrate was peeled off, and vacuum-laminated on a circuit board having a line / space of 0.05 mm / 0.05 mm. Thereafter, in the case of a dry resist film produced using the active energy ray-curable resin composition, exposure, development, and post-curing were performed in the same procedure as in the migration test to produce a circuit board with a cover coat layer. In the case of a dry resist film produced using the thermosetting resin composition, the transparent substrate was peeled off after post-curing without performing exposure and development, thereby producing a circuit board with a cover coat layer.
The circuit board with the cover coat layer is bent 180 degrees so that the cover coat layer is on the outside, and a 500 g weight is placed on the bent portion for 5 seconds. Then, the bent portion is returned to the original flat state, and 500 g is returned again. Was placed for 5 seconds, and this was folded once. Whether or not cracks occurred in the cover coat layer was observed with a microscope "VHX-900" manufactured by KEYENCE CORPORATION, and the number of times of bending without cracks was evaluated.
The number of times of bending until a crack occurred in the bent portion where a load of 500 g was applied was counted. The evaluation criteria are as follows.

：: 5 times or more. Very good.
：: 3 or more and less than 5 times. Good: 2 times or more and less than 3 times. No problem in practical use.
X: Less than 2 times. Not practical.

<Light shielding>
The optical density was measured by a Macbeth densitometer (GRETAGD200-II) after peeling off the peelable sheet of the dry resist film with the substrate, and the optical density (OD) at the film thickness in each example was determined. The evaluation criteria are as follows.

：: 1.5 or more. Good.
〇: 1 or more and less than 1.5. No problem in practical use.
×: less than 1. Not practical.

<Flame retardant>
A printed wiring board with an electromagnetic wave shielding sheet was formed in the same procedure as the migration test except that the electromagnetic wave shielding sheet was applied to the entire surface of the cover coat layer. Cut out to a length of 200 mm and a width of 50 mm, roll it in the width direction so that the electromagnetic wave shielding sheet surface is on the outside, form a tube, and mark the position 125 mm in the length direction from one end of the tube. Samples were used. Using this test sample, a vertical flammability test based on the UL-94 thin vertical flammability test standard of Underwriter's Laboratories Inc. was performed at n = 10 to evaluate the flame retardancy. The results were evaluated by the number of times satisfying the following criteria.

All of the following conditions (A) to (E) are satisfied.
(A) The total quenching time after 10 times of flame contact, that is, 5 test pieces twice each, is 50 seconds or less.
(B) Five test pieces were subjected to flame contact twice each, and the extinction time after each flame contact was within 10 seconds.
(C) There is no ignition of absorbent cotton 300 mm below by the dripping material in all the test pieces.
(D) For all test pieces, glowing after the second flame contact is within 30 seconds.
(E) For all test pieces, do not frame until the clamp.

A: The condition is satisfied all 10 times out of 10 times. Very good.
・ ・ ・: The condition is satisfied 9 times out of 10 times. No problem in practical use.
×: Eight or less satisfy the condition out of 10 times. Not practical.

  From the results in Table 3, it was confirmed that the connection reliability was improved in the circuit to which the electromagnetic wave shielding sheet was bonded by improving the ion migration resistance.

DESCRIPTION OF SYMBOLS 1 Polyimide film 2 Comb-shaped signal wiring 2 'for cathode electrode Cathode electrode connection point 3 Comb-shaped signal wiring 3' for anode electrode Anode electrode connection point 4 Cover coat layer 5 Electromagnetic wave shielding sheet 5a Insulation layer 5b Conductive layer

Claims (4)

An electromagnetic wave shielding sheet, a cover coat layer, a printed wiring board with an electromagnetic wave shielding sheet comprising a substrate having signal wiring and an insulating base material,
The electromagnetic wave shielding sheet has a layer containing phosphorus (P),
The cover coat layer has a cured product of the resin layer containing the coloring agent,
A printed wiring board with an electromagnetic wave shielding sheet, wherein a shortest distance between the layer containing phosphorus (P) and the signal wiring is in a range of 5 μm or more and 100 μm or less.   The printed wiring board with an electromagnetic wave shielding sheet according to claim 1, wherein the cured product of the resin layer has a storage elastic modulus at 85 ° C of 1.0E + 06 to 1.0E + 10Pa.   The printed wiring board according to claim 1, wherein the electromagnetic wave shielding sheet has at least an insulating layer and a conductive layer, and the conductive layer contains phosphorus (P).   The electromagnetic wave shielding sheet has at least an insulating layer and a conductive layer, wherein the conductive layer does not contain phosphorus (P), and the insulating layer contains phosphorus (P). 3. The printed wiring board with the electromagnetic wave shielding sheet according to 1 or 2.