JP6841707B2 - Method of manufacturing electromagnetic wave shield film and method of manufacturing printed wiring board with electromagnetic wave shield film - Google Patents

Description

The present invention relates to a thermosetting composition, a cured product, an electromagnetic wave shielding film and a method for producing the same, and a printed wiring board with an electromagnetic wave shielding film and a method for producing the same.

In order to shield electromagnetic noise generated from the flexible printed wiring board and electromagnetic noise from the outside, an electromagnetic shielding film composed of an insulating resin layer, a metal thin film layer adjacent to the insulating resin layer, and an adhesive layer is used as an insulating film ( It may be provided on the surface of a flexible printed wiring board via a coverlay film (see, for example, Patent Document 1).

In the electromagnetic wave shielding film, for example, a coating liquid containing a thermosetting resin, a curing agent, and a solvent is applied to one side of a first release film, which is a carrier film, and dried to form an insulating resin layer. It is manufactured by providing a metal thin film layer and an adhesive layer (for example, a conductive adhesive layer) on the surface of the insulating resin layer.

The first release film is insulated after an electromagnetic wave shielding film is attached to the surface of an insulating film provided on the surface of a flexible printed wiring board (FPC) so that the conductive adhesive layer is in contact with the insulating film. It is peeled off from the resin layer.

Japanese Unexamined Patent Publication No. 2016-086120

An electromagnetic wave shield film attached to an FPC or the like is required to have improved flame retardancy. Further, conventionally, in the production of an electromagnetic wave shielding film, the base film may be curled when the insulating resin layer or the adhesive layer is formed on the base film, and it is required to suppress this curl. Further, conventionally, in the production of an electromagnetic wave shielding film, a laminating process of adhering an insulating resin layer or an adhesive layer to a metal thin film layer may be repeated a plurality of times, and reduction of this number of times is also required.

The present invention is a thermosetting composition and a cured product thereof capable of forming an insulating resin layer and an adhesive layer having less curing shrinkage (shrinkage at the time of curing), excellent adhesiveness, and improved flame retardancy, and the thermosetting. Provided are an electromagnetic wave shielding film provided with a layer containing the sex composition or the cured product and a method for producing the same, and a printed wiring board with an electromagnetic wave shielding film and a method for producing the same.

[1] The compound (1) contains one or more epoxy group-containing compounds and one or more selected from the group of the compound (1) represented by the following formula (1), and the compound (1) is at 25 ° C. and 1 atm. A thermosetting composition that is a liquid.
[2] The thermosetting composition according to [1], wherein the compound (1) is a compound represented by the following formula (1b).
[3] The thermosetting composition according to [1], wherein the compound (1) is a compound represented by the following formula (1b-1).
[4] The thermosetting composition according to any one of [1] to [3], further comprising a black colorant.
[5] The thermosetting composition according to any one of [1] to [3], further comprising conductive particles.
[6] The thermosetting composition according to any one of [1] to [5], further comprising one or more selected from the group of compounds represented by the following formula (2).
[7] The thermosetting composition according to any one of [1] to [6], further comprising a solvent.
[8] The cured product of the thermosetting composition according to any one of [1] to [7].
[9] An electromagnetic wave shielding film having an insulating resin layer, a metal thin film layer adjacent to the insulating resin layer, and an adhesive layer adjacent to the side opposite to the insulating resin layer of the metal thin film layer. An electromagnetic wave shielding film in which at least one of the insulating resin layer and the adhesive layer is the thermosetting composition according to any one of [1] to [7] or the cured product according to [8].
[10] The electromagnetic wave shielding film according to [9], wherein the adhesive layer is an anisotropic conductive adhesive layer.
[11] A printed wiring board provided with a printed circuit on at least one side of the substrate, an insulating film adjacent to the surface of the printed wiring board on the side provided with the printed circuit, and the adhesive layer on the insulating film. A printed wiring board with an electromagnetic wave shielding film, comprising the electromagnetic wave shielding film according to [9] or [10] provided adjacent to each other.
[12] The method for producing an electromagnetic wave shielding film according to [9], wherein the coating film obtained by applying the thermosetting composition to a base film is heated to cure it to an arbitrary degree. A method for producing an electromagnetic wave shielding film, which comprises a step of forming at least one of the insulating resin layer and the adhesive layer.
[13] The method for producing an electromagnetic wave shielding film according to [9], wherein the insulating resin layer, the metal thin film layer, and the adhesive layer are laminated in this order, and then heated and pressurized. A method for producing an electromagnetic wave shielding film, which comprises a step of adhering at least one of the insulating resin layer and the metal thin film layer and the metal thin film layer and the adhesive layer by the application.
[14] The method for manufacturing a printed wiring board with an electromagnetic wave shielding film according to [11], wherein the adhesive layer of the electromagnetic wave shielding film is laminated on the surface of the insulating film of the printed wiring board so as to be in contact with the surface of the insulating film. , A manufacturing method comprising a crimping step of adhering the adhesive layer to the surface of the insulating film by crimping them.
[15] The production method according to [14], wherein when crimping in the crimping step, the insulating resin layer and the adhesive layer are pressed while being heated.
[16] The method according to [14] or [15], which comprises a curing step of curing the thermosetting composition by further heating the insulating resin layer and the adhesive layer after the crimping step. Production method.

In the above formula (1), R ₁ , R ₂ and R ₃ are independent hydrogen atoms or arbitrary substituents, and R ₁ and R ₂ may be bonded to each other to form a ring.
In the formula (1b), R ₂ is a hydrogen atom or an arbitrary substituent, and R ₂ may be bonded to a phenyl group bonded to a phosphorus atom to form a ring; R ₃ is a hydroxyl group and a carboxyl group. It is an arbitrary substituent having at least one of them. ]

In the above formula (2), L1 and L2 are independently single-bonded or divalent linking groups having 1 to 8 carbon atoms, m and n are independently integers of 1 to 5, and m + n is 2 to 2. 6. Of the hydrogen atoms bonded to the benzene ring, any one or more hydrogen atoms are substituted with (HO-L1-) groups, and any other one or more hydrogen atoms are (-L2). Any one or more hydrogen atoms substituted with a −COOH) group and not substituted with a (HO-L1-) group and a (−L2-COOH) group may be substituted with any substituent. .. ]

According to the thermosetting composition of the present invention and the cured product thereof, it is possible to form an insulating resin layer and an adhesive layer having improved flame retardancy and adhesiveness.
The electromagnetic wave shielding film of the present invention and the printed wiring board with the electromagnetic wave shielding film have improved flame retardancy.
According to the method for producing an electromagnetic wave shielding film of the present invention, the shrinkage of the coating film made of the thermosetting composition applied on the base film during curing is small, so that the base film and the insulating resin formed on the base film are not shrunk. Curling of the layer or the adhesive layer can be suppressed. Further, the number of laminating treatments for adhering the insulating resin layer or the adhesive layer to the metal thin film layer can be reduced.
According to the method for manufacturing a flexible printed wiring board with an electromagnetic wave shielding film of the present invention, the adhesive layer has excellent adhesiveness, so that the metal thin film and the adhesive layer can be easily adhered by pressure bonding.

It is sectional drawing which shows one Embodiment of the electromagnetic wave shielding film of this invention. It is sectional drawing which shows the other embodiment of the electromagnetic wave shielding film of this invention. It is sectional drawing which shows the manufacturing process of the electromagnetic wave shielding film of FIG. It is sectional drawing which shows the manufacturing process of the electromagnetic wave shielding film of FIG. It is sectional drawing which shows one Embodiment of the printed wiring board with the electromagnetic wave shielding film of this invention. It is sectional drawing which shows the manufacturing process of the printed wiring board with the electromagnetic wave shielding film of FIG.

The definitions of the following terms apply throughout the specification and claims.
"Epoxy" is the base name for the -O-atomic group that bonds to the carbon of two atoms bonded by a carbon chain.
"(Meta) acryloyl group" is a general term for acryloyl group and methacryloyl group.
The "isotropic conductive adhesive layer" means a conductive adhesive layer having conductivity in the thickness direction and the surface direction.
The "anisotropic adhesive layer" means a conductive adhesive layer having conductivity in the thickness direction and not in the plane direction.
The “conductive adhesive layer having no conductivity in the plane direction” means a conductive adhesive layer having a surface resistance of 1 × 10 ⁴ Ω or more.
For the average particle size of the particles, 30 particles are randomly selected from the microscopic image of the particles, the minimum and maximum diameters of each particle are measured, and the median value between the minimum and maximum diameters is the particle of one particle. It is a value obtained by arithmetically averaging the particle diameters of the 30 measured particles as the diameter. The same applies to the average particle size of the conductive particles.
The thickness of the film (release film, insulating film, etc.), coating film (insulating resin layer, conductive adhesive layer, etc.), metal thin film layer, etc. can be determined by observing the cross section of the measurement target using a microscope at 5 locations. It is a value obtained by measuring the thickness and averaging it.
The storage elastic modulus is calculated from the stress applied to the measurement target and the detected strain, and is measured as one of the viscoelastic properties by using a dynamic viscoelastic measuring device that outputs as a function of temperature or time.
For the surface resistance, two thin film metal electrodes (length 10 mm, width 5 mm, distance between electrodes 10 mm) formed by depositing gold on quartz glass are used, and an object to be measured is placed on the electrodes to be measured. It is the resistance between the electrodes measured with a measurement current of 1 mA or less by pressing a region of 10 mm × 20 mm of the object to be measured with a load of 0.049 N from above the object.

<< Thermosetting composition >>
The first aspect of the present invention includes one or more kinds of epoxy group-containing compounds and one or more kinds selected from the group of the compound (1) represented by the following formula (1), and the compound (1) is 25. A thermosetting composition that is liquid at ° C. and 1 atm.

［式（１）中、Ｒ_１、Ｒ_２及びＲ_３はそれぞれ独立に水素原子又は任意の置換基であり、Ｒ_１及びＲ_２が互いに結合して環を形成してもよい。］

[In formula (1), R ₁ , R ₂ and R ₃ are independent hydrogen atoms or arbitrary substituents, and R ₁ and R ₂ may be bonded to each other to form a ring. ]

_{Arbitrary substituents of R 1} , R ₂ and R ₃ of compound (1) may be monovalent substituents or may be bonded to each other by divalent substituents to form a ring. ..
_{Examples of the monovalent substituent of R 1} , R ₂ and R ₃ of the compound (1) include an aromatic group, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, and 1 carbon number. Examples thereof include 10 to 10 alkoxy groups and halogens. -O-, -C (= O)-, -C (= O) O-, -OC (=), except when one or more of the methylene groups of the alkyl group are bonded to each other. O) It may be replaced by −, −NH−, or −S−.
Examples of the aromatic group include a phenyl group, a naphthyl group, an anthracenyl group and the like. The aromatic group may be bonded to a phosphorus atom or an oxygen atom via a linking group having 1 to 3 carbon atoms.

The compound (1b) represented by the following formula (1b) is preferable from the viewpoint of further enhancing the function of the compound (1) as a flame retardant and a curing agent.

［式（１ｂ）中、Ｒ_２は水素原子又は任意の置換基であり、リン原子に結合したフェニル基にＲ_２が結合して環を形成していてもよく；Ｒ_３は水酸基及びカルボキシル基のうち少なくとも一方を１つ以上有する任意の置換基である。］

[In formula (1b), R ₂ is a hydrogen atom or an arbitrary substituent, and R ₂ may be bonded to a phenyl group bonded to a phosphorus atom to form a ring; R ₃ is a hydroxyl group and a carboxyl group. It is an arbitrary substituent having at least one of them. ]

_{The arbitrary substituent of R 2} of compound (1b) may be a monovalent substituent or a divalent substituent by substituting any hydrogen atom of the phenyl group bonded to the phosphorus atom. They may be combined to form a ring.
_{As the monovalent substituent of R 2} of compound (1b), the _{same substituent as R 2} of compound (1) described above can be exemplified.

_{R 3} of the compound (1b) is a substituent having one or more hydroxyl groups, a substituent having one or more carboxyl groups, or a substituent having one or more hydroxyl groups and one or more carboxyl groups. Is preferable.

As the substituent represented by R ₃ of the compound (1b), a straight, one or more hydroxyl groups or carboxyl groups the hydrogen atom of the said alkyl group branched or cyclic substituted Substituents are preferred. Among them, it is more preferable that it is a branched-chain alkyl group having 1 to 20 carbon atoms and has one or more hydroxyl groups or carboxyl groups in each branched chain. Further, except when one or more of the methylene groups of the alkyl group are bonded to each other, -O-, -C (= O)-, -C (= O) O- or -OC It is preferably substituted with (= O) −, and more preferably substituted with −C (= O) O− or −OC (= O) −.
The compound (1b) having a suitable substituent tends to be a highly fluid liquid at 25 ° C. and 1 atm, has excellent dispersibility in a thermosetting composition, has less curing shrinkage, and has excellent adhesiveness. An insulating resin layer and an adhesive layer can be formed.

A preferable specific example of the compound (1b) is a phosphorus compound represented by the following formula (1b-1). This phosphorus compound is a liquid at 25 ° C. and 1 atm, and it is preferable to use a glycol-based solvent such as ethylene glycol or propylene glycol as a diluting solvent thereof.

(Epoxy group-containing compound)
The epoxy group-containing compound contained in the thermosetting composition is preferably a compound having two or more epoxy groups, and more preferably a resin having two or more epoxy groups (epoxy resin). It is more preferable that the resin is an epoxy resin having epoxy groups at least at both ends.
With the above-mentioned suitable epoxy group-containing compound, an adhesive layer having less curing shrinkage of the thermosetting composition, enhanced adhesive strength, and excellent adhesiveness to a metal can be easily formed.
The epoxy group-containing compound contained in the thermosetting composition may be one kind or two or more kinds.

As used herein, an epoxy group is a monovalent group obtained by removing one arbitrary hydrogen atom from an epoxy. Examples of the epoxy include epoxyethane (also known as ethylene oxide) and 1,3'-epoxypropane (also known as trimethylene oxide, oxetane).
As the epoxy group-containing compound, a glycidyl group-containing compound having a glycidyl group in which a methylene group is bonded to a monovalent bond of the epoxy group is preferable.

A known epoxy resin can be applied as the epoxy resin, and can be appropriately selected depending on the use of the thermosetting composition. The epoxy resin contained in the thermosetting composition may be one kind or two or more kinds.
Specific examples of the epoxy resin include epoxy resins obtained by a condensation reaction between bisphenol having two hydroxyphenyl groups and epichlorohydrin, and examples thereof include bisphenol A type epoxy resin and bisphenol F type epoxy resin. Other examples include polyfunctional epoxy resins such as dicyclopentadiene type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, and triphenylmethane type epoxy resin. it can.

The content ratio of the epoxy group-containing compound and the compound (1) in the thermosetting composition is preferably a content ratio sufficient for the compound (1) to cure the epoxy group-containing compound. Specifically, it is preferable that the number of moles of the active hydrogen group in the compound (1) is 0.01 mol or more and 1.5 mol or less per 1 mol of the epoxy group of the epoxy group-containing compound. Here, the active hydrogen group refers to a hydrogen, a hydroxyl group, and a carboxyl group bonded to a phosphorus atom of compound (1).
When it is at least the above lower limit, the amount of the compound (1) that reacts with the epoxy group-containing compound increases, the curing shrinkage of the thermosetting composition is further reduced, and the flame retardancy, hardness, and adhesive strength of the cured product are further improved. Can be enhanced.
When it is not more than the above upper limit value, the curing rate of the thermosetting composition becomes appropriate, the hardness of the cured product tends to be uniform, and it is possible to prevent the hardness from becoming excessively high or excessively low.
When the thermosetting composition contains a curing agent other than the compound (1), the content ratio of the compound (1) and the epoxy group-containing compound may be outside the above range.

In the thermosetting composition, the total content of the compound (1) with respect to the total 100 parts by mass of the epoxy group-containing compound is preferably 10 parts by mass or more and 1000 parts by mass or less, and 50 parts by mass or more and 500 parts by mass or less. More preferably, it is 100 parts by mass or more and 300 parts by mass or less.
When it is at least the above lower limit, the amount of the compound (1) that reacts with the epoxy group-containing compound increases, the curing shrinkage of the thermosetting composition is further reduced, and the flame retardancy, hardness, and adhesive strength of the cured product are further improved. Can be enhanced.
When it is not more than the above upper limit value, the curing rate of the thermosetting composition becomes appropriate, the hardness of the cured product tends to be uniform, and it is possible to prevent the hardness from becoming excessively high or excessively low.

(Additive)
The thermosetting composition may contain one or more additives other than the epoxy group-containing compound and the compound (1) as optional components as long as the curing is not hindered.
Examples of the additive include a conductive material, a colorant, a filler, a solvent, a curing agent, a curing accelerator, a low stress agent, and the like.

The thermosetting composition preferably contains the compound (2) represented by the following formula (2).
The compound (2) in the thermosetting composition functions as a curing agent by reacting the epoxy group of the epoxy group-containing compound with the active hydrogen group of the hydroxyl group or the carboxyl group of the compound (2) by heat. Further, by containing the compound (2), the adhesiveness of the cured product of the thermosetting composition to the metal can be improved.

Particularly suitable compounds (2) include, for example, 4-hydroxybenzoic acid represented by the following formula (2a) and gallic acid (gallic acid) represented by the following formula (2b).

In the above formula (2), L1 and L2 are independently single-bonded or divalent linking groups having 1 to 8 carbon atoms, m and n are independently integers of 1 to 5, and m + n is 2 to 2. 6. Of the hydrogen atoms bonded to the benzene ring, any one or more hydrogen atoms are substituted with (HO-L1-) groups, and any other one or more hydrogen atoms are (-L2). Any one or more hydrogen atoms substituted with a −COOH) group and not substituted with a (HO-L1-) group and a (−L2-COOH) group may be substituted with any substituent. ..
In the formula (2a) and the formula (2b), any one or more hydrogen atoms bonded to the benzene ring may be substituted with any substituent.

In the formula (2), m is preferably 1 to 3, and n is preferably 1 to 3.
In the above formula (2), except for the case of m = 1 and n = 1, the hydrogen atom of the carboxyl group of the (-L2-COOH) group is linear, branched or cyclic having 1 to 10 carbon atoms. It may be substituted with an alkyl group of carboxylic acid ester to form a carboxylic acid ester.

In the formula (2), the divalent linking group having 1 to 8 carbon atoms represented by L1 and L2 is preferably an alkylene group having 1 to 8 carbon atoms and an alkenylene group having 2 to 8 carbon atoms. The alkylene group and one or more methylene groups constituting the alkenylene group are −O−, −C (= O) −, −C (= O) O−, except when oxygen atoms are bonded to each other. It may be replaced by —O—C (= O) −, −NH−, or −S−.
When m is 2 or more, the plurality of L1s may be the same or different from each other.
When n is 2 or more, the plurality of L2s may be the same or different from each other.

The arbitrary substituent which may substitute the hydrogen atom of the benzene ring includes, for example, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms. , Halogen and the like. The methylene group of one or more of the alkyl groups is −O−, −C (= O) −, −C (= O) O−, −OC (=) except when oxygen atoms are bonded to each other. O) It may be replaced by −, −NH−, or −S−.

Specific examples of the compound (2) include mono-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid (salicylic acid), 2- (hydroxymethyl) benzoic acid, vanillic acid, syringic acid and the like. Hydroxybenzoic acid and its derivatives;
2,3-Dihydroxybenzoic acid (2-pyrocatechuic acid), 2,4-dihydroxybenzoic acid (β-resorcinic acid), 2,5-dihydroxybenzoic acid (gentidic acid), 2,6-dihydroxybenzoic acid (γ-) Dihydroxybenzoic acid such as resorcinic acid), 3,4-dihydroxybenzoic acid (protocatechuic acid), 3,5-dihydroxybenzoic acid (α-resorcinic acid), 3,6-dihydroxybenzoic acid, orseric acid and derivatives thereof;
Trihydroxybenzoic acid such as 3,4,5-trihydroxybenzoic acid (gallic acid), 2,4,6-trihydroxybenzoic acid (phloroglucinolcarboxylic acid) and its derivatives;
Hydroxykeiic acid such as melilotate, phloretic acid, umbelic acid, caffeic acid, ferulic acid, sinapic acid and its derivatives;
Aromatic dicarboxylic acids having one or more hydroxy groups such as 5-hydroxyisophthalic acid, 2-hydroxyterephthalic acid, 2,5-dihydroxyterephthalic acid and derivatives thereof; and the like can be mentioned.
The compound (2) contained in the thermosetting composition may be one kind or two or more kinds.

The content ratio of the epoxy group-containing compound and the compound (2) in the thermosetting composition may be a content ratio sufficient for the compound (2) to cure the epoxy group-containing compound. Specifically, it is preferable that the number of moles of the active hydrogen group in the compound (2) is 0.5 mol or more and 1.5 mol or less per 1 mol of the epoxy group of the epoxy group-containing compound. Here, the active hydrogen group refers to both the hydroxyl group and the carboxyl group of the compound (2).
When it is at least the above lower limit, the amount of the compound (2) that reacts with the epoxy group-containing compound increases, and the hardness and adhesive strength of the cured product of the thermosetting composition can be further increased.
When it is not more than the above upper limit value, the curing rate of the thermosetting composition becomes appropriate, the hardness of the cured product tends to be uniform, and it is possible to prevent the hardness from becoming excessively high or excessively low.

In the thermosetting composition, the total content of the compound (2) with respect to the total 100 parts by mass of the epoxy group-containing compound is preferably 1 part by mass or more and 100 parts by mass or less, and 5 parts by mass or more and 50 parts by mass or less. More preferably, it is 10 parts by mass or more and 30 parts by mass or less.
When it is at least the above lower limit, the amount of the compound (2) that reacts with the epoxy group-containing compound increases, and the hardness and adhesive strength of the cured product of the thermosetting composition can be further increased.
When it is not more than the above upper limit value, the curing rate of the thermosetting composition becomes appropriate, the hardness of the cured product tends to be uniform, and it is possible to prevent the hardness from becoming excessively high or excessively low.

When the thermosetting composition is applied to an adhesive layer of an electromagnetic wave shielding film described later, a conductive adhesive layer can be formed by adding a conductive material to the thermosetting composition. As the conductive material, conductive particles are preferable.

Examples of the conductive particles include metal particles such as silver, platinum, gold, copper, nickel, palladium, aluminum and solder, graphite powder, calcined carbon particles, and plated calcined carbon particles.
As will be described later, the preferable average particle diameter of the conductive particles is, for example, about 0.1 μm or more and 50 μm or less.
The content of the conductive particles with respect to the total mass of the solid content excluding the solvent of the thermosetting composition is, for example, 1% by mass or more and 50% by mass or less, and preferably 10% by mass or more and 30% by mass or less. .. Within this range, the conductive adhesive layer described later can be easily formed.

Examples of the low stress agent (stress relaxation agent) include vinyl acetate resin and silicone compounds.
The content of the low stressing agent with respect to the total mass of the solid content excluding the solvent of the thermosetting composition is, for example, 10% by mass or more and 80% by mass or less, and 30% by mass, although it depends on the type. % Or more and 70% by mass or less is preferable. Within this range, a cured product having good flexibility can be easily formed.

Examples of the colorant include carbon black, azo dyes, metal complexes and the like. Among these, a black colorant is preferable.
The content of the colorant with respect to the total mass of the solid content excluding the solvent of the thermosetting composition depends on the type, but includes, for example, 1% or more and 30% or less, and 5% or more and 20% or less. Is preferable.
Since it can be sufficiently colored within the above range, an insulating resin layer that can be easily distinguished from the release film can be easily formed.

Examples of the filler include powders of quartz glass, talc, fused silica, crystalline silica, alumina and the like.

The solvent is preferably one capable of dissolving or dispersing the epoxy group-containing compound and the compound (1), for example, esters (butyl acetate, ethyl acetate, methyl acetate, isopropyl acetate, ethylene glycol monoacetate, etc.), ketones (methyl ethyl ketone, etc.). , Methyl isobutyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, etc.), alcohols (methanol, ethanol, isopropanol, butanol, propylene glycol monomethyl ether, propylene glucol, etc.) and the like.

Examples of the curing agent include polyfunctional phenol resins such as dicyclopentadiene type phenol resin, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, biphenyl type phenol resin, and triphenylmethane type phenol resin.

Examples of the curing accelerator include organic phosphorus compounds such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine, imidazole compounds such as 2-ethyl-4-methylimidazole, 2-methylimidazole, and phenylimidazole, 1,8-. Examples thereof include tertiary amine compounds such as diazabicyclo (5.4.0) undecene-7 (DBU), 1,5-diazabicyclo (4.3.0) nonen-5 (DBN), and N-aminoethylpiperazine.

The additive may contain other components other than the above components. Examples of other components include a mold release agent, a flame retardant other than the compound (1), a pigment, an ion trapping agent, a coupling agent, a heat resistant agent, and the like.

The content of each of the curing agent, the curing accelerator, the filler, and the other components with respect to the total mass of the thermosetting composition is not particularly limited, and for example, the total content thereof is 0.1. It can be prepared in the range of mass% or more and 30 mass% or less.

(Method for producing thermosetting composition)
The thermosetting composition according to the first aspect of the present invention is prepared by appropriately blending, for example, a solvent, the epoxy group-containing compound, compound (1), additives and the like, and mixing them by a conventional method using a ball mill, a blender or the like. Can be prepared by.

<Effect>
The compound (1) contained in the thermosetting composition of the present invention has flame retardancy and is liquid at 25 ° C. and 1 atm, so that it has excellent dispersibility in the thermosetting composition and is a cured product thereof. The distribution inside is also uniform, and it is difficult to reduce the hardness of the cured product or coating film. Further, since it is a liquid, the adhesiveness to the base material is improved, and the layer containing the cured product can be sufficiently adhered to the base material such as the metal thin film layer by a relatively gentle laminating treatment.
The compound (1) contained in the thermosetting composition of the present invention functions as a flame retardant at the combustion temperature of the cured product. Although the details of this chemical mechanism have not been clarified, the compound (1) forms a flame-retardant char during combustion by the same mechanism as the conventional triphenyl phosphate, and the combustion of the cured product is suppressed. It is thought that.
Further, the compound (1) contained in the thermosetting composition of the present invention functions as a low stress agent that suppresses curing shrinkage when the thermosetting composition is cured. The details of this chemical mechanism are unknown, but the substituent of compound (1) reacts with the epoxy group by heat, and compound (1) is added to the epoxy group-containing compound to cure and cure. It is considered that the contraction is suppressed.

《Hardened product》
The second aspect of the present invention is a cured product of the thermosetting composition of the first aspect. The degree of curing of the cured product may be any of a state closer to uncured than the B stage, a state of being B-staged (semi-cured), and a state of being completely cured.
An example of an embodiment of a cured product is a coating film obtained by curing a thermosetting composition applied to the surface of a base material.
Since the coating film has excellent adhesiveness to the substrate, the coating film is useful as an adhesive layer. Further, when the base material is made of metal, if the coating film contains the compound (2), the adhesiveness to the metal surface is more excellent. Therefore, the coating film exhibits excellent adhesiveness as an insulating resin layer and an adhesive layer to be laminated on the metal thin film layer of the electromagnetic wave shielding film described later.
The film thickness of the coating film is not particularly limited, and examples thereof include 1 μm and more and 100 μm or less.

The method for obtaining the cured product is not particularly limited as long as it can supply heat for curing by reacting the epoxy group-containing compound with the compound (1), and for example, it is injected into a container or a mold and heated. A method of coating the surface of the base material and heating the surface of the base material can be mentioned.
The heating temperature at the time of obtaining the cured product may be at least the temperature at which the reaction occurs, preferably at room temperature or higher, and from the viewpoint of facilitating reaction control, 50 to 200 ° C., 1 minute or more and 24 hours or less. It is preferable to cure under the heating conditions of.
The curing reaction may be completely cured by one heating, or may be cured stepwise through the B stage by a plurality of heatings.

<Effect>
Since the cured product of the second aspect of the present invention contains the epoxy group-containing compound and the compound (1), it exhibits excellent adhesiveness to the base material that was in contact with the cured product at the time of curing. Further, since it contains the compound (1), it is also excellent in flame retardancy.

《Electromagnetic wave shield film》
A third aspect of the present invention is an electromagnetic wave shielding film having an insulating resin layer, a metal thin film layer adjacent to the insulating resin layer, and an adhesive layer adjacent to the side opposite to the insulating resin layer of the metal thin film layer. At least one of the insulating resin layer and the adhesive layer is an electromagnetic wave shielding film which is a cured product of the second aspect.
Hereinafter, the description will be made with reference to the drawings, but the dimensional ratios in the drawings may differ from the actual ones for convenience of explanation.

FIG. 1 is a cross-sectional view showing the electromagnetic wave shielding film 1 of the first embodiment, and FIG. 2 is a cross-sectional view showing the electromagnetic wave shielding film 1 of the second embodiment.
The electromagnetic wave shielding film 1 has an insulating resin layer 10; a metal thin film layer 22 adjacent to the insulating resin layer 10; an adhesive layer 24 adjacent to the side opposite to the insulating resin layer 10 of the metal thin film layer 22; an insulating resin layer. It has a first release film 30 adjacent to the side opposite to the metal thin film layer 22 of 10; and a second release film 40 adjacent to the side opposite to the metal thin film layer 22 of the adhesive layer 24.

The electromagnetic wave shielding film 1 of the first embodiment is an example in which the adhesive layer 24 is an anisotropic conductive adhesive layer 24.
The electromagnetic wave shielding film 1 of the second embodiment is an example in which the adhesive layer 26 is an isotropic conductive adhesive layer 26.

(Insulating resin layer)
The insulating resin layer 10 is a protective layer of the metal thin film layer 22 after the electromagnetic wave shielding film 1 is attached to the surface of the insulating film provided on the surface of the flexible printed wiring board and the first release film 30 is peeled off. It becomes.

The insulating resin layer 10 is a coating film formed by applying a coating material containing a thermosetting resin and a curing agent and semi-curing or curing; a coating film formed by applying a coating material containing a thermoplastic resin; Examples thereof include a layer made of a film obtained by melt-molding a composition containing a thermoplastic resin. From the viewpoint of heat resistance at the time of soldering or the like, a coating film formed by applying a paint containing a thermosetting resin and a curing agent and semi-curing or curing is preferable.

Examples of the thermosetting resin include amide resin, epoxy resin, phenol resin, amino resin, alkyd resin, urethane resin, synthetic rubber, and ultraviolet curable acrylate resin. As the thermosetting resin, an amide resin and an epoxy resin are preferable from the viewpoint of excellent heat resistance.
Examples of the curing agent include known curing agents depending on the type of thermosetting resin.

The insulating resin layer 10 is one of a colorant (pigment, dye, etc.) and a filler, or one of them, in order to conceal the printed circuit of the printed wiring board and impart designability to the printed wiring board with the electromagnetic wave shielding film. Both may be included.
As one or both of the colorant and the filler, a pigment or a filler is preferable from the viewpoint of weather resistance, heat resistance and concealing property, and a black pigment or a black pigment is used from the viewpoint of concealing property and design property of a printed circuit. Combinations with other pigments or fillers are more preferred.

The insulating resin layer 10 may contain a flame retardant other than the compound (1).
The insulating resin layer 10 may contain other components, if necessary, as long as the effects of the present invention are not impaired.

The surface resistance of the insulating resin layer 10 ^{is preferably 1 × 10 6} Ω or more from the viewpoint of electrical insulation. The surface resistance of the insulating resin layer 10 ^{is preferably 1 × 10 19} Ω or less from a practical point of view.
The thickness of the insulating resin layer 10 is preferably 0.1 μm or more and 30 μm or less, and more preferably 0.5 μm or more and 20 μm or less. When the thickness of the insulating resin layer 10 is at least the lower limit of the above range, the insulating resin layer 10 can sufficiently exert the function as a protective layer. When the thickness of the insulating resin layer 10 is not more than the upper limit of the above range, the electromagnetic wave shielding film 1 can be thinned.

(Conductive layer)
The conductive layer 20 includes a metal thin film layer 22 adjacent to the insulating resin layer 10 and a conductive adhesive layer (irregular conductive adhesive layer 24) which is the outermost layer of the conductive layer 20 on the opposite side of the insulating resin layer 10. Alternatively, a conductive layer (I) having an isotropic conductive adhesive layer 26); or a conductive layer (II) composed of only the isotropic conductive adhesive layer 26 can be mentioned. As the conductive layer 20, the conductive layer (I) is preferable because it can sufficiently function as an electromagnetic wave shielding layer.

(Metal thin film layer)
The metal thin film layer 22 is a layer made of a metal thin film. Since the metal thin film layer 22 is formed so as to spread in the plane direction, it has conductivity in the plane direction and functions as an electromagnetic wave shield layer or the like.

Examples of the metal thin film layer 22 include a vapor deposition film formed by physical vapor deposition (vacuum vapor deposition, sputtering, ion beam deposition, electron beam deposition, etc.) or CVD, a plating film formed by plating, a metal foil, and the like. A thin-film deposition film and a plating film are preferable from the viewpoint of excellent surface-direction conductivity, and the thickness can be reduced, and even if the thickness is thin, the surface-direction conductivity is excellent and can be easily formed by a dry process. A thin-film deposition film is more preferable, and a thin-film deposition film by physical vapor deposition is even more preferable.

Examples of the metal constituting the metal thin film layer 22 include aluminum, silver, copper, gold, and conductive ceramics. Copper is preferable from the viewpoint of electrical conductivity, and conductive ceramics is preferable from the viewpoint of chemical stability.

The surface resistance of the metal thin film layer 22 is preferably 0.001 Ω or more and 1 Ω or less, and more preferably 0.001 Ω or more and 0.5 Ω or less. When the surface resistance of the metal thin film layer 22 is equal to or higher than the lower limit of the above range, the metal thin film layer 22 can be sufficiently thinned. When the surface resistance of the metal thin film layer 22 is not more than the upper limit of the above range, it can sufficiently function as an electromagnetic wave shielding layer.

The thickness of the metal thin film layer 22 is preferably 0.01 μm or more and 1 μm or less, and more preferably 0.05 μm or more and 1 μm or less. When the thickness of the metal thin film layer 22 is 0.01 μm or more, the conductivity in the plane direction is further improved. When the thickness of the metal thin film layer 22 is 0.05 μm or more, the shielding effect of electromagnetic noise is further improved. When the thickness of the metal thin film layer 22 is not more than the upper limit of the above range, the electromagnetic wave shielding film 1 can be thinned. In addition, the productivity and flexibility of the electromagnetic wave shielding film 1 are improved.

(Conductive adhesive layer)
The conductive adhesive layer has at least conductivity in the thickness direction and has adhesiveness.
As the conductive adhesive layer, the anisotropic conductive adhesive layer 24 which has conductivity in the thickness direction and does not have conductivity in the surface direction, or has conductivity in the thickness direction and the surface direction, etc. The anisotropic conductive adhesive layer 26 can be mentioned. As the conductive adhesive layer in the conductive layer (I), the conductive adhesive layer can be thinned and the amount of conductive particles can be reduced, and as a result, the electromagnetic wave shielding film 1 can be thinned, and the electromagnetic wave shielding film 1 can be used. The anisotropic conductive adhesive layer 24 is preferable from the viewpoint of improving the property. As the conductive adhesive layer in the conductive layer (I), the isotropic conductive adhesive layer 26 is preferable from the viewpoint that it can sufficiently function as an electromagnetic wave shielding layer.

As the conductive adhesive layer in the present embodiment, a coating film composed of the thermosetting composition of the first aspect of the present invention or the cured product of the second aspect is used. Since the coating film is thermosetting, it has excellent heat resistance. Further, since the compound (1) is contained, shrinkage during curing is small, curling of the film can be suppressed, and flame retardancy after curing is also excellent. Further, when the epoxy group-containing compound and the compound (2) are contained, the adhesiveness to the metal thin film layer 22 is particularly excellent.
The degree of curing of the thermosetting composition constituting the conductive adhesive layer is not particularly limited, and may be in an uncured state, a B-staged state, or a completely cured state.
The cured product constituting the conductive adhesive layer may be in a state closer to uncured than in the B stage, in a B-staged state, or in a completely cured state.

The thermosetting anisotropic conductive adhesive layer 24 is composed of, for example, a thermosetting composition 24a containing conductive particles 24b.
The thermosetting isotropic conductive adhesive layer 26 is composed of, for example, a thermosetting composition 26a containing conductive particles 26b.

The thermosetting composition may contain a rubber component (carboxy-modified nitrile rubber, acrylic rubber, etc.) for imparting flexibility, a tackifier, and the like.
The thermosetting composition may contain a flame retardant other than the compound (1), if necessary.
The thermosetting composition may contain a cellulose resin, microfibrils (glass fiber, etc.) in order to increase the strength of the conductive adhesive layer and improve the punching characteristics.
The thermosetting composition may contain other components, if necessary, as long as the effects of the present invention are not impaired.

Examples of the conductive particles include metal (silver, platinum, gold, copper, nickel, palladium, aluminum, solder, etc.) particles, graphite powder, calcined carbon particles, plated calcined carbon particles, and the like. As the conductive particles, metal particles are preferable, and copper particles are preferable from the viewpoint that the conductive adhesive layer has an appropriate hardness and the pressure loss in the conductive adhesive layer during hot pressing can be reduced. More preferred.

The average particle diameter of the conductive particles 24b in the anisotropic conductive adhesive layer 24 is preferably 2 μm or more and 26 μm or less, and more preferably 4 μm or more and 16 μm or less. When the average particle diameter of the conductive particles 24b is at least the lower limit of the above range, the thickness of the anisotropic conductive adhesive layer 24 can be secured, and sufficient adhesive strength can be obtained. When the average particle diameter of the conductive particles 24b is equal to or less than the upper limit of the above range, the fluidity of the anisotropic conductive adhesive layer 24 (following the shape of the through holes of the insulating film) can be ensured, and the insulating film The inside of the through hole can be sufficiently filled with the conductive adhesive.

The average particle diameter of the conductive particles 26b in the isotropic conductive adhesive layer 26 is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.2 μm or more and 1 μm or less. When the average particle diameter of the conductive particles 26b is equal to or greater than the lower limit of the above range, the number of contact points of the conductive particles 26b increases, and the conductivity in the three-dimensional direction can be stably increased. When the average particle diameter of the conductive particles 26b is equal to or less than the upper limit of the above range, the fluidity of the isotropic conductive adhesive layer 26 (following the shape of the through holes of the insulating film) can be ensured, and the insulating film The inside of the through hole can be sufficiently filled with the conductive adhesive.

The proportion of the conductive particles 24b in the anisotropic conductive adhesive layer 24 is preferably 1% by volume or more and 30% by volume or less, preferably 2% by volume or more and 15% by volume, out of 100% by volume of the anisotropic conductive adhesive layer 24. The following is more preferable. When the ratio of the conductive particles 24b is equal to or higher than the lower limit of the above range, the conductivity of the anisotropic conductive adhesive layer 24 becomes good. When the proportion of the conductive particles 24b is not more than the upper limit of the above range, the adhesiveness and fluidity (following the shape of the through hole of the insulating film) of the anisotropic conductive adhesive layer 24 are improved. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved.

The proportion of the conductive particles 26b in the isotropic conductive adhesive layer 26 is preferably 50% by volume or more and 80% by volume or less, preferably 60% by volume or more and 70% by volume, out of 100% by volume of the isotropic conductive adhesive layer 26. The following is more preferable. When the ratio of the conductive particles 26b is equal to or higher than the lower limit of the above range, the conductivity of the isotropic conductive adhesive layer 26 becomes good. When the ratio of the conductive particles 26b is not more than the upper limit of the above range, the adhesiveness and fluidity (following the shape of the through hole of the insulating film) of the isotropic conductive adhesive layer 26 are improved. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved.

The storage elastic modulus of the conductive adhesive layer at 180 ° C. ^{is preferably 1 × 10 3} Pa or more and 5 × 10 ⁷ Pa or less, and more preferably 5 × 10 ³ Pa or more and 1 × 10 ⁷ Pa or less. When the storage elastic modulus of the conductive adhesive layer at 180 ° C. is equal to or higher than the lower limit of the above range, the conductive adhesive layer has a more appropriate hardness, and the conductive adhesive layer at the time of hot pressing Pressure loss can be reduced. As a result, the conductive adhesive layer and the printed circuit of the printed wiring board are sufficiently adhered, and the conductive adhesive layer is securely electrically connected by the printed circuit of the printed wiring board through the through hole of the insulating film. To. When the storage elastic modulus of the conductive adhesive layer at 180 ° C. is not more than the upper limit of the above range, the flexibility of the electromagnetic wave shielding film 1 is improved. As a result, the electromagnetic wave shielding film 1 is likely to sink into the through hole of the insulating film, and the conductive adhesive layer is reliably electrically connected through the through hole of the insulating film by the printed circuit of the printed wiring board.

The surface resistance of the anisotropic conductive adhesive layer 24 ^{is preferably 1 × 10 4} Ω or more and 1 × 10 ¹⁶ Ω or less, and more preferably 1 × 10 ⁶ Ω or more and 1 × 10 ¹⁴ Ω or less. When the surface resistance of the anisotropic conductive adhesive layer 24 is at least the lower limit of the above range, the content of the conductive particles 24b can be suppressed to a low level. If the surface resistance of the anisotropic conductive adhesive layer 24 is equal to or less than the upper limit of the above range, there is no problem in practical use.

The surface resistance of the isotropic conductive adhesive layer 26 is preferably 0.05 Ω or more and 2.0 Ω or less, and more preferably 0.1 Ω or more and 1.0 Ω or less. When the surface resistance of the isotropic conductive adhesive layer 26 is equal to or higher than the lower limit of the above range, the content of the conductive particles 26b is suppressed to a low level, the viscosity of the conductive adhesive does not become too high, and the coatability is further improved. It will be good. Further, the fluidity of the isotropic conductive adhesive layer 26 (following the shape of the through hole of the insulating film) can be further ensured. When the surface resistance of the isotropic conductive adhesive layer 26 is equal to or less than the upper limit of the above range, the entire surface of the isotropic conductive adhesive layer 26 has uniform conductivity.

The thickness of the anisotropic conductive adhesive layer 24 is preferably 3 μm or more and 25 μm or less, and more preferably 5 μm or more and 15 μm or less. When the thickness of the anisotropic conductive adhesive layer 24 is equal to or greater than the lower limit of the above range, the fluidity of the anisotropic conductive adhesive layer 24 (following the shape of the through hole of the insulating film) can be ensured. The inside of the through hole of the insulating film can be sufficiently filled with the conductive adhesive. When the thickness of the anisotropic conductive adhesive layer 24 is not more than the upper limit of the above range, the electromagnetic wave shielding film 1 can be thinned. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved.

The thickness of the isotropic conductive adhesive layer 26 is preferably 5 μm or more and 20 μm or less, and more preferably 7 μm or more and 17 μm or less. When the thickness of the isotropic conductive adhesive layer 26 is at least the lower limit of the above range, the conductivity of the isotropic conductive adhesive layer 26 becomes good, and the isotropic conductive adhesive layer 26 can sufficiently function as an electromagnetic wave shielding layer. Further, the fluidity of the isotropic conductive adhesive layer 26 (following the shape of the through hole of the insulating film) can be ensured, and the inside of the through hole of the insulating film can be sufficiently filled with the conductive adhesive, so that the resistance can be improved. Foldability can be ensured, and the isotropic conductive adhesive layer 26 does not tear even if it is repeatedly bent. When the thickness of the isotropic conductive adhesive layer 26 is not more than the upper limit of the above range, the electromagnetic wave shielding film 1 can be thinned. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved.

(First release film)
The first release film 30 serves as a carrier film for the insulating resin layer 10 and the conductive layer 20, and improves the handleability of the electromagnetic wave shielding film 1. The first release film 30 is peeled off from the insulating resin layer 10 after the electromagnetic wave shielding film 1 is attached to a printed wiring board or the like.

The first release film 30 has a release film main body 32 and an adhesive layer 34 provided on the surface of the release film main body 32 on the insulating resin layer 10 side.

The resin material of the release film body 32 includes polyethylene terephthalate (hereinafter, also referred to as PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, and ethylene-vinyl acetate. Examples thereof include copolymers, polyvinyl chloride, polyvinylidene chloride, synthetic rubbers, and liquid crystal polymers. As the resin material, PET is preferable from the viewpoint of heat resistance (dimensional stability) and price when manufacturing the electromagnetic wave shielding film 1.

The release film body 32 may contain one or both of a colorant (pigment, dye, etc.) and a filler.
Either one or both of the colorant and the filler are different from the insulating resin layer 10 in that they can be clearly distinguished from the insulating resin layer 10 and it is easy to notice the unpeeled residue of the first release film 30 after hot pressing. Colored ones are preferred, white pigments, fillers, or combinations of white pigments with other pigments or fillers are more preferred.

The storage elastic modulus of the release film main body 32 at 180 ° C. ^{is preferably 8 × 10 7} Pa or more and 5 × 10 ⁹ Pa, and more preferably 1 × 10 ⁸ Pa or more and 8 × 10 ⁸ Pa. When the storage elastic modulus of the release film main body 32 at 180 ° C. is equal to or higher than the lower limit of the above range, the first release film 30 has an appropriate hardness, and the first release during hot pressing. The pressure loss in the mold film 30 can be reduced. When the storage elastic modulus of the release film main body 32 at 180 ° C. is equal to or less than the upper limit of the above range, the flexibility of the first release film 30 becomes good.

The thickness of the release film main body 32 is preferably 3 μm or more and 75 μm or less, and more preferably 12 μm or more and 50 μm or less. When the thickness of the release film main body 32 is at least the lower limit value in the above range, the handleability of the electromagnetic wave shield film 1 is good. When the thickness of the release film main body 32 is not more than the upper limit of the above range, heat is easily transferred to the conductive adhesive layer when the conductive adhesive layer of the electromagnetic wave shielding film 1 is hot-pressed on the surface of the insulating film. ..

The pressure-sensitive adhesive layer 34 is formed by applying, for example, a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive to the surface of the release film main body 32. Since the first release film 30 has the pressure-sensitive adhesive layer 34, when the second release film 40 is peeled off from the conductive adhesive layer, or the electromagnetic wave shield film 1 is attached to a printed wiring board or the like by hot pressing. At that time, the release of the first release film 30 from the insulating resin layer 10 is suppressed, and the first release film 30 can sufficiently serve as a protective film.

The pressure-sensitive adhesive is such that the first release film 30 can be peeled from the insulating resin layer 10 after the hot pressing without the first release film 30 being easily peeled from the insulating resin layer 10 before the hot pressing. It is preferable that the pressure-sensitive adhesive layer 34 is provided with an appropriate degree of adhesiveness.
Examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a rubber-based pressure-sensitive adhesive.
The glass transition temperature of the pressure-sensitive adhesive is preferably -100 to 60 ° C, more preferably -60 to 40 ° C.

The thickness of the first release film 30 is preferably 25 μm or more and 125 μm or less, and more preferably 38 μm or more and 100 μm or less. When the thickness of the first release film 30 is at least the lower limit of the above range, the handleability of the electromagnetic wave shielding film 1 is good. When the thickness of the first release film 30 is equal to or less than the upper limit of the above range, heat is applied to the conductive adhesive layer when the conductive adhesive layer of the electromagnetic wave shielding film 1 is hot-pressed on the surface of the insulating film. Easy to convey.

(Second release film)
The second release film 40 protects the conductive adhesive layer and improves the handleability of the electromagnetic wave shielding film 1. The second release film 40 is peeled off from the conductive adhesive layer before the electromagnetic wave shielding film 1 is attached to a printed wiring board or the like.

The second release film 40 has, for example, a release film main body 42 and a release agent layer 44 provided on the surface of the release film main body 42 on the conductive adhesive layer side.

Examples of the resin material of the release film main body 42 include the same resin materials as those of the release film main body 32.
The release film main body 42 may contain a colorant, a filler and the like.
The thickness of the release film body 42 is preferably 5 μm or more and 500 μm or less, more preferably 10 μm or more and 150 μm or less, and further preferably 25 μm or more and 100 μm or less.

The release agent layer 44 is formed by treating the surface of the release film main body 42 with a release agent. Since the second release film 40 has the release agent layer 44, when the second release film 40 is peeled from the conductive adhesive layer, the second release film 40 can be easily peeled off and is conductive. The release adhesive layer is less likely to break.
As the release agent, a known release agent may be used.

The thickness of the release agent layer 44 is preferably 0.05 μm or more and 30 μm or less, and more preferably 0.1 μm or more and 20 μm or less. When the thickness of the release agent layer 44 is within the above range, the second release film 40 can be more easily peeled off.

(Thickness of electromagnetic wave shield film)
The thickness of the electromagnetic wave shield film 1 (excluding the release film) is preferably 5 μm or more and 50 μm or less, and more preferably 8 μm or more and 30 μm or less. If the thickness of the electromagnetic wave shielding film 1 that does not include the release film is equal to or greater than the lower limit of the above range, it is unlikely to break when the first release film 30 is peeled off. When the thickness of the electromagnetic wave shielding film 1 not including the release film is equal to or less than the upper limit of the above range, the printed wiring board with the electromagnetic wave shielding film can be thinned.

<< Manufacturing method of electromagnetic wave shield film >>
A fourth aspect of the present invention is the method for producing an electromagnetic wave shielding film according to the third aspect.
In the first embodiment of the present embodiment, the insulating resin layer and the above-mentioned insulating resin layer are cured by heating a coating film obtained by applying the thermosetting composition of the first aspect to a base film and curing the coating film to an arbitrary degree. A method for producing the electromagnetic wave shielding film, which comprises a step of forming at least one of the adhesive layers.

The form of the base film is not particularly limited, and examples thereof include a carrier film, a first release film, and a second release film. A metal thin film layer may be formed in advance on the coated surface of the thermosetting composition of these base films. Specifically, for example, the base film may be a laminated film of a carrier film and a metal thin film layer.

The temperature and time for heating the coating film are not particularly limited as long as the temperature and time allow the thermosetting composition to cure to a desired degree, and for example, 50 ° C. or higher and 200 ° C. or lower, 10 seconds or longer and 10 minutes or shorter. Can be mentioned.

<Effect>
In the present embodiment, since the compound (1) is contained in the thermosetting composition, it is possible to suppress the curing shrinkage of the coating film when it is cured. As a result, curling of the base film on which the insulating resin layer or the adhesive layer is formed on the surface is suppressed, and the production yield of the electromagnetic wave shielding film can be improved.

In the second embodiment of the fourth aspect, the insulating resin layer, the metal thin film layer, and the adhesive layer are laminated in this order, and the insulating resin layer is subjected to a laminating treatment of heating and pressurizing. A method for producing an electromagnetic wave shielding film, which comprises a step of adhering at least one of the metal thin film layer and the adhesive layer and the adhesive layer.

As a method of laminating each layer in the above order, for example, the insulating resin layer and the metal thin film layer are formed on the first release film in this order, and the adhesive layer is formed on the second release film. A method of placing the second release film on the first release film so as to attach the adhesive layer to the metal thin film layer can be mentioned.
Instead of the above method, the insulating resin layer is formed on the first release film, the adhesive layer and the metal thin film layer are formed on the second release film in this order, and the metal thin film layer is formed. A method of placing the first release film on the second release film so as to attach the insulating resin layer can also be exemplified.
The heating temperature and pressure conditions for the laminating treatment are preferably the conditions in the step (c3) described in detail later.

<Effect>
In the present embodiment, since the compound (1) is contained in at least one of the insulating resin layer and the adhesive layer, the insulating resin layer containing the compound (1) and the metal thin film of the adhesive layer It has excellent adhesiveness and can be easily adhered by a relatively gentle laminating process. As a result, the manufacturing efficiency of the electromagnetic wave shielding film can be improved.
Hereinafter, the method for producing the electromagnetic wave shielding film according to the present invention will be illustrated in more detail.

The electromagnetic wave shielding film of the present invention is produced, for example, by the following method (α), the following method (β), or the like. As the method for producing the electromagnetic wave shielding film of the present invention, the method (α) is preferable from the viewpoint of improving the adhesiveness between the insulating resin layer and the metal thin film layer.

The method (α) is a method having the following steps (a) to (c).
Step (a): A step of providing a metal thin film layer on the surface of the carrier film, if necessary.
Step (b): A step of providing an insulating resin layer on the surface of a metal thin film layer provided on the surface of a carrier film.
Step (c): A step of peeling the carrier film from the metal thin film layer and providing an adhesive layer on the surface of the metal thin film layer opposite to the insulating resin layer.

The method (β) is a method having the following steps (x) to (z).
Step (x): A step of providing an insulating resin layer on the surface of the first release film.
Step (y): A step of providing a metal thin film layer on the surface of the insulating resin layer.
Step (z): A step of providing an adhesive layer on the surface of the metal thin film layer.

Hereinafter, the method (α) will be described in detail.
(Step (a))
Examples of the carrier film include those having a base material layer and an adhesive layer provided on the surface of the base material layer.
Examples of the resin material for the base material layer include those similar to the resin material for the base material layer 32 of the first release film 30.
As the pressure-sensitive adhesive in the pressure-sensitive adhesive layer, a known pressure-sensitive adhesive may be used.

Examples of the method for forming the metal thin film layer include a method of forming a vapor-deposited film by physical vapor deposition and CVD, a method of forming a plating film by plating, a method of attaching a metal foil, and the like. From the viewpoint that a metal thin film layer having excellent surface conductivity can be formed, a method of forming a thin film by physical vapor deposition or CVD, or a method of forming a plating film by plating is preferable, and the thickness of the metal thin film layer can be reduced. A method of forming a thin-film deposition film by physical vapor deposition or CVD is more preferable because a metal thin-film layer having excellent surface conductivity can be formed even if the thickness is thin, and a metal thin-film layer can be easily formed by a dry process. , A method of forming a vapor-deposited film by physical vapor deposition is more preferable.

The step (a) may be omitted by obtaining a commercially available laminate having a metal thin film layer provided on the surface of the carrier film.

(Step (b))
As a method of providing the insulating resin layer on the surface of the metal thin film layer, for example, a photocurable composition is applied to the surface of the metal thin film layer, dried if it contains a solvent, and then irradiated with light (ultraviolet rays, etc.). There is a method of semi-curing or curing.

In the step (b), the first release film may be provided on the surface of the insulating resin layer.
As a method of providing the first release film on the surface of the insulating resin layer, a first release film having a base material layer and an adhesive layer is provided on the surface of the insulating resin layer, and the insulating resin layer and the adhesive layer are provided. Method of pasting so as to be in contact with; After providing the pressure-sensitive adhesive layer on the surface of the insulating resin layer, the surface of the insulating resin layer is pasted by pasting the base material layer of the first release film on the surface of the pressure-sensitive adhesive layer. A method of providing the first release film and the like can be mentioned.

(Step (c))
In the step (c), the second release film with an adhesive layer provided with an adhesive layer on the surface of the second release film is placed on the surface of the metal thin film layer opposite to the insulating resin layer. The thin film layer and the adhesive layer may be attached so as to be in contact with each other; the adhesive layer may be provided directly on the surface of the metal thin film layer. Further, after the adhesive layer is provided on the surface of the metal thin film layer, the second release film may be attached to the surface of the adhesive layer.

As a method of providing the adhesive layer on the surface of the second release film or the metal thin film layer, an adhesive, a solvent and, if necessary, conductive particles are applied to the surface of the second release film or the metal thin film layer. Examples thereof include a method of applying the containing coating liquid and drying it.

(One Embodiment of the manufacturing method of the electromagnetic wave shield film)
Hereinafter, a method for manufacturing the electromagnetic wave shielding film 1 of the first embodiment shown in FIG. 1 will be described with reference to FIGS. 3 and 4.

Step (a):
As shown in FIG. 3, a metal thin film layer 22 is provided by depositing metal on the surface of the carrier film 100 having the base material layer 102 and the release agent layer 104 on the release agent layer 104 side.

Step (b1):
As shown in FIG. 3, a coating liquid for forming an insulating resin layer (thermosetting composition of the first aspect of the present invention) containing a black colorant (not shown) is applied to the surface of the metal thin film layer 22. The insulating resin layer 10 is provided by drying while heating.

Step (b2):
As shown in FIG. 3, the first release film 30 having the base material layer 32 and the pressure-sensitive adhesive layer 34 is brought into contact with the surface of the insulating resin layer 10 so that the insulating resin layer 10 and the pressure-sensitive adhesive layer 34 are in contact with each other. paste.

Step (c1):
As shown in FIG. 4, an adhesive 24a, conductive particles 24b, and a solvent are applied to the surface of the second release film 40 having the base material layer 42 and the release agent layer 44 on the release agent layer 44 side. The coating liquid for forming an adhesive layer (the thermosetting composition of the first aspect of the present invention) containing the coating liquid (the thermosetting composition of the first aspect of the present invention) is applied and dried while heating to provide an anisotropic conductive adhesive layer 24 (adhesive layer 24). .. In this way, a second release film with an adhesive layer is obtained.

Step (c2):
As shown in FIG. 4, the carrier film 100 is peeled from the metal thin film layer 22 in the laminate obtained in the step (b2). In this way, a first release film with an insulating resin layer and a metal thin film layer is obtained.

Step (c3):
As shown in FIG. 4, the first release film with the insulating resin layer and the metal thin film layer and the second release film with the adhesive layer are combined with the metal thin film layer 22 and the idiosyncratic conductive adhesive layer 24. The insulating resin layer and the adhesive layer are cured by heating them as necessary to obtain an electromagnetic wave shielding film 1.

In the step (c3), when the metal thin film layer 22 and the anisotropic conductive adhesive layer 24 are bonded to each other, it is preferable to perform a laminating process (a process of adhering in a laminated state) under milder conditions than a hot press. ..
The heating temperature in the laminating treatment is preferably, for example, 50 to 100 ° C.
The pressure in the laminating treatment is, for example, preferably 100 kPa (0.1 MPa) or less, more preferably 0.1 kPa or more and 20 kPa or less, and further preferably 1 kPa or more and 10 kPa or less.
The heating and pressurizing time in the laminating treatment is preferably, for example, 10 seconds or more and 30 minutes or less, and more preferably 30 seconds or more and 10 minutes or less.
By laminating at the above-mentioned suitable heating temperature, pressure, and treatment time, the metal thin film layer 22 and the anisotropic conductive adhesive layer 24 can be easily bonded with sufficient adhesive force.

<Effect>
In the electromagnetic wave shielding film 1 according to the present invention, since at least one of the insulating resin layer 10 and the anisotropic conductive adhesive layer 24 is formed by the thermosetting composition of the first aspect, it is flame-retardant. Is also excellent. Further, during the production thereof, shrinkage of the thermosetting composition during curing is suppressed, and the metal of the insulating resin layer 10 and the anisotropic conductive adhesive layer 24 is subjected to the laminating treatment under relatively mild conditions. Sufficient adhesive force to the thin film layer 22 can be easily obtained.
Further, when the thermosetting composition contains the compound (2), the adhesive force of the insulating resin layer 10 and the anisotropic conductive adhesive layer 24 to the metal thin film layer 22 is further enhanced, and the release film is formed. At the time of peeling, the metal thin film layer 22 and the insulating resin layer 10 or the anisotropic conductive adhesive layer 24 are prevented from peeling.

The electromagnetic wave shielding film according to the present invention is not limited to the embodiments shown in the illustrated examples, as long as at least one of the insulating resin layer and the conductive adhesive layer contains the epoxy group-containing compound and the compound (1). ..
For example, the second release film may have a pressure-sensitive adhesive layer instead of the release agent layer when the surface tackiness of the conductive adhesive layer is low. Alternatively, the second release film may be omitted.
If the release film body has high releasability, the second release film may not have a release agent layer and may consist only of the release film body.
The insulating resin layer may be two or more layers.

<Printed wiring board with electromagnetic wave shield film>
FIG. 5 is a cross-sectional view showing an embodiment of a printed wiring board with an electromagnetic wave shielding film of the present invention.
The flexible printed wiring board 2 with an electromagnetic wave shielding film includes a flexible printed wiring board 50, an insulating film 60, and an electromagnetic wave shielding film 1 of the first embodiment.
The flexible printed wiring board 50 is provided with a printed circuit 54 on at least one side of the base film 52.
The insulating film 60 is provided on the surface of the flexible printed wiring board 50 on the side where the printed circuit 54 is provided.
The anisotropic conductive adhesive layer 24 of the electromagnetic wave shielding film 1 is adhered to and cured on the surface of the insulating film 60. Further, the anisotropic conductive adhesive layer 24 is electrically connected to the print circuit 54 through a through hole (not shown) formed in the insulating film 60.
In the flexible printed wiring board 2 with an electromagnetic wave shielding film, the second release film 40 is peeled off from the anisotropic conductive adhesive layer 24.

When the first release film 30 is no longer needed in the flexible printed wiring board 2 with the electromagnetic wave shielding film, the first release film 30 is peeled off from the insulating resin layer 10.

In the vicinity of the printed circuit 54 (signal circuit, ground circuit, ground layer, etc.) excluding the portion having the through hole, the metal thin film layer 22 of the electromagnetic wave shielding film 1 forms the insulating film 60 and the anisotropic conductive adhesive layer 24. They are arranged so as to face each other apart from each other.
The separation distance between the printed circuit 54 and the metal thin film layer 22 excluding the portion having the through hole is substantially equal to the sum of the thickness of the insulating film 60 and the thickness of the anisotropic conductive adhesive layer 24. The separation distance is preferably 30 μm or more and 200 μm or less, and more preferably 60 μm or more and 200 μm or less. If the separation distance is smaller than 30 μm, the impedance of the signal circuit becomes low. Therefore, in order to have a characteristic impedance such as 100Ω, the line width of the signal circuit must be reduced, and the variation in the line width is the variation in the characteristic impedance. Therefore, the reflected resonance noise due to the impedance mismatch can easily get on the electric signal. If the separation distance is larger than 200 μm, the flexible printed wiring board 2 with the electromagnetic wave shielding film becomes thick, and the flexibility becomes insufficient.

(Flexible printed wiring board)
The flexible printed wiring board 50 is a printed circuit (power supply circuit, ground circuit, ground layer, etc.) obtained by processing a copper foil of a copper-clad laminate into a desired pattern by a known etching method.
As the copper-clad laminate, a copper foil is attached to one or both sides of the base film 52 via an adhesive layer (not shown); a resin solution or the like forming the base film 52 is cast on the surface of the copper foil. Things etc. can be mentioned.
Examples of the material of the adhesive layer include epoxy resin, polyester, polyimide, polyamide-imide, polyamide, phenol resin, urethane resin, acrylic resin, melamine resin and the like.
The thickness of the adhesive layer is preferably 0.5 μm or more and 30 μm or less.

(Base film)
As the base film 52, a film having heat resistance is preferable, a polyimide film and a liquid crystal polymer film are more preferable, and a polyimide film is further preferable.
The surface resistance of the base film 52 ^{is preferably 1 × 10 6} Ω or more from the viewpoint of electrical insulation. The surface resistance of the base film 52 ^{is preferably 1 × 10 19} Ω or less from a practical point of view.
The thickness of the base film 52 is preferably 5 μm or more and 200 μm or less, more preferably 6 μm or more and 25 μm or less, and more preferably 10 μm or more and 25 μm or less from the viewpoint of flexibility.

(Print circuit)
Examples of the copper foil constituting the printed circuit 54 (signal circuit, ground circuit, ground layer, etc.) include rolled copper foil, electrolytic copper foil, and the like, and rolled copper foil is preferable from the viewpoint of flexibility.
The thickness of the copper foil is preferably 1 μm or more and 50 μm or less, and more preferably 18 μm or more and 35 μm or less.
The end (terminal) of the print circuit 54 in the length direction is not covered with the insulating film 60 or the electromagnetic wave shielding film 1 because of solder connection, connector connection, component mounting, and the like.

(Insulation film)
The insulating film 60 (coverlay film) is formed by forming an adhesive layer (not shown) on one side of an insulating film main body (not shown) by applying an adhesive, attaching an adhesive sheet, or the like.
The surface resistance of the insulating film body ^{is preferably 1 × 10 6} Ω or more from the viewpoint of electrical insulation. The surface resistance of the insulating film body ^{is preferably 1 × 10 19} Ω or less from a practical point of view.
As the insulating film main body, a film having heat resistance is preferable, a polyimide film and a liquid crystal polymer film are more preferable, and a polyimide film is further preferable.
The thickness of the insulating film body is preferably 1 μm or more and 100 μm or less, and more preferably 3 μm or more and 25 μm or less from the viewpoint of flexibility.
Examples of the material of the adhesive layer include epoxy resin, polyester, polyimide, polyamide-imide, polyamide, phenol resin, urethane resin, acrylic resin, melamine resin, polystyrene, polyolefin and the like. The epoxy resin may contain a rubber component (carboxy-modified nitrile rubber, etc.) for imparting flexibility.
The thickness of the adhesive layer is preferably 1 μm or more and 100 μm or less, and more preferably 1.5 μm or more and 60 μm or less.

The shape of the opening of the through hole is not particularly limited. Examples of the shape of the opening of the through hole 62 include a circular shape, an elliptical shape, and a quadrangle shape.

(Manufacturing method of printed wiring board with electromagnetic wave shield film)
The printed wiring board with an electromagnetic wave shielding film of the present invention can be manufactured, for example, by a method having the following steps (d) to (g).
Step (d): A step of providing an insulating film having through holes formed at positions corresponding to the printed circuit on the surface of the printed wiring board on the side where the printed circuit is provided to obtain a printed wiring board with the insulating film.
Step (e): After the step (d), the printed wiring board with the insulating film and the electromagnetic wave shielding film of the present invention from which the second release film is peeled off are brought into contact with the surface of the insulating film by the conductive adhesive layer. By stacking them in such a manner and heat-pressing them, a conductive adhesive layer is adhered to the surface of the insulating film, and the conductive adhesive layer is electrically connected to the printed circuit through a through hole to generate an electromagnetic wave. The process of obtaining a printed wiring board with a shield film.
Step (f): A step of peeling off the first release film when the first release film is no longer needed after the step (e).
Step (g): A step of main curing the anisotropic conductive adhesive layer between the steps (e) and the step (f), or after the step (f), if necessary.

Hereinafter, a method of manufacturing a flexible printed wiring board with an electromagnetic wave shielding film will be described with reference to FIG.

(Step (d))
As shown in FIG. 6, an insulating film 60 having a through hole 62 formed at a position corresponding to the printed circuit 54 is superposed on the flexible printed wiring board 50, and an adhesive layer of the insulating film 60 is formed on the surface of the flexible printed wiring board 50. A flexible printed wiring board 3 with an insulating film is obtained by adhering (not shown) and curing the adhesive layer. The adhesive layer of the insulating film 60 may be temporarily adhered to the surface of the flexible printed wiring board 50, and the adhesive layer may be mainly cured in the step (g).
The adhesive layer is adhered and cured by, for example, hot pressing with a press machine (not shown) or the like.

(Step (e))
As shown in FIG. 6, an electromagnetic wave shielding film 1 from which the second release film 40 has been peeled off is placed on the flexible printed wiring board 3 with an insulating film and heat-pressed to form an anisotropic conductivity on the surface of the insulating film 60. A flexible printed wiring board 2 with an electromagnetic wave shielding film is obtained in which the adhesive layer 24 is adhered and the anisotropic conductive adhesive layer 24 is electrically connected to the printed circuit 54 through the through hole 62.

Adhesion and curing of the anisotropic conductive adhesive layer 24 are performed, for example, by hot pressing with a press machine (not shown) or the like.
The hot pressing time is 20 seconds or more and 60 minutes or less, more preferably 30 seconds or more and 30 minutes or less. When the heat pressing time is equal to or greater than the lower limit of the above range, the anisotropic conductive adhesive layer 24 is adhered to the surface of the insulating film 60. When the heat pressing time is not more than the upper limit of the above range, the manufacturing time of the flexible printed wiring board 2 with the electromagnetic wave shielding film can be shortened.

The temperature of the hot press (the temperature of the hot plate of the press machine) is preferably 140 ° C. or higher and 190 ° C. or lower, more preferably 150 ° C. or higher and 175 ° C. or lower. When the temperature of the hot press is equal to or higher than the lower limit of the above range, the anisotropic conductive adhesive layer 24 is adhered to the surface of the insulating film 60. Moreover, the time of hot pressing can be shortened. When the temperature of the hot press is not more than the upper limit of the above range, deterioration of the electromagnetic wave shielding film 1, the flexible printed wiring board 50, and the like can be suppressed.

The pressure of the hot press is preferably 0.5 MPa or more and 20 MPa or less, and more preferably 1 MPa or more and 16 MPa or less. When the pressure of the hot press is equal to or higher than the lower limit of the above range, the anisotropic conductive adhesive layer 24 is adhered to the surface of the insulating film 60. Moreover, the time of hot pressing can be shortened. When the pressure of the hot press is not more than the upper limit of the above range, damage to the electromagnetic wave shielding film 1, the flexible printed wiring board 50, etc. can be suppressed.

(Step (f))
As shown in FIG. 6, when the first release film is no longer needed, the first release film 30 is peeled off from the insulating resin layer 10.

(Step (g))
When the heat pressing time in the step (e) is as short as 20 seconds or more and 10 minutes or less, the anisotropic conductive adhesive layer is formed between the steps (e) and the step (f) or after the step (f). It is preferable to perform the main curing of 24.
The main curing of the anisotropic conductive adhesive layer 24 is performed using, for example, a heating device such as an oven.
The heating time is 15 minutes or more and 120 minutes or less, preferably 30 minutes or more and 60 minutes or less. When the heating time is equal to or greater than the lower limit of the above range, the anisotropic conductive adhesive layer 24 can be sufficiently cured. When the heating time is not more than the upper limit of the above range, the manufacturing time of the flexible printed wiring board 2 with the electromagnetic wave shielding film can be shortened.
The heating temperature (atmospheric temperature in the oven) is preferably 120 ° C. or higher and 180 ° C. or lower, and preferably 120 ° C. or higher and 150 ° C. or lower. When the heating temperature is equal to or higher than the lower limit of the above range, the heating time can be shortened. When the heating temperature is not more than the upper limit of the above range, deterioration of the electromagnetic wave shielding film 1, the flexible printed wiring board 50, and the like can be suppressed.

<Effect>
In the method for manufacturing the flexible printed wiring board 2 with the electromagnetic wave shielding film described above, since the electromagnetic wave shielding film 1 is used, the insulating resin layer 10 and the anisotropic conductive adhesive layer are used when bonding by hot pressing. The curing shrinkage of 24 is small, the generation of curl can be suppressed, and the flame retardancy after curing is also excellent.
Further, since the flexible printed wiring board 2 with the electromagnetic wave shielding film after manufacturing is provided with the electromagnetic wave shielding film 1, it is excellent in flame retardancy. Further, when the thermosetting composition contains the compound (2), the adhesive force between the insulating resin layer 10 and the anisotropic conductive adhesive layer 24 with respect to the metal thin film layer 22 is further enhanced, and the first release is achieved. When the mold film 30 is peeled off, the metal thin film layer 22 and the insulating resin layer 10 or the anisotropic conductive layer 24 are prevented from peeling off.

(Other embodiments)
The printed wiring board with an electromagnetic wave shielding film of the present invention includes a printed wiring board, an insulating film adjacent to the surface of the printed wiring board on the side where the printed circuit is provided, and a conductive layer adjacent to the insulating film. It is not limited to the embodiment of the illustrated example as long as it has the electromagnetic wave shielding film of the present invention electrically connected to the printed circuit through the through hole formed in the insulating film.
For example, the flexible printed wiring board may have a ground layer on the back surface side. Further, the flexible printed wiring board may have printed circuits on both sides, and an insulating film and an electromagnetic wave shielding film may be attached to both sides.
An inflexible rigid printed circuit board may be used instead of the flexible printed wiring board.
Instead of the electromagnetic wave shielding film 1 of the first embodiment, the electromagnetic wave shielding film 1 or the like of the second embodiment may be used.

(Example 1)
As a coating liquid (thermosetting composition) for forming an insulating resin layer, 100 g of a bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER (registered trademark) 828) and 20 g of N-aminoethylpiperazin (curing agent). 2 g of carbon black (black colorant) and 11.0 g of a phosphorus compound represented by the above formula (1b-1) (manufactured by Sanko Co., Ltd., M-Ester, concentration 80% by mass, solvent: ethylene glycol). A coating solution dissolved in 200 g of a solvent (methyl ethyl ketone) was prepared. As a result, the phosphorus compound was blended so as to be about 0.016 mol per 1 mol of the epoxy group of the epoxy resin.

As a coating liquid (thermocurable composition) for forming an adhesive layer, a vinyl acetate resin solution (manufactured by Showa Denko Co., Ltd., Vinylol (registered trademark) K-2S, solid content: 15 mass, solvent: methyl isobutyl ketone, methyl ethyl ketone, 100 g of methanol), 4.1 g of epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER® 1031S, solid content: 60 mass, solvent: methyl ethyl ketone), and 4.5 g of copper powder (average particle size: 8 μm). , 5.8 g of a phosphorus compound represented by the above formula (1b-1) (M-Ester manufactured by Sanko Co., Ltd., concentration 80% by mass, solvent: ethylene glycol) and gallic acid represented by the above formula (2b). A mixture of 0.5 g of the above was prepared. As a result, the amount of the phosphorus compound was about 0.84 mol and the amount of the active hydrogen group of the gallic acid was about 0.6 mol per 1 mol of the epoxy group of the epoxy resin.

Step (b1):
As shown in FIG. 3, a laminate in which a metal thin film layer is provided on the surface of a carrier film (manufactured by Toray KP Film Co., Ltd., Capy Seduce (registered trademark), copper foil with a release layer, copper foil thickness: 0. A coating liquid for forming an insulating resin layer was applied to the surface of a metal thin film layer of 5 μm, copper foil surface resistance: 0.015 Ω, PET thickness: 50 μm) using a # 8 bar coater. The coating film was dried at 150 ° C. for 1 minute to provide an insulating resin layer (thickness: 10 μm, surface resistance: 1.0 E + 12 Ω or more) on the surface of the metal thin film layer. At this time, it was confirmed whether the entire film was curled in the direction of the insulating resin layer due to the curing shrinkage of the coating liquid for forming the insulating resin layer.

Step (b2):
On the surface of the insulating resin layer, a first release film (manufactured by Panac, PanaProtect (registered trademark) GN, adhesive film, adhesive strength: 0.49 N / cm, PET thickness: 75 μm) is applied to the insulating resin layer. It was attached so as to be in contact with the pressure-sensitive adhesive layer to obtain a laminate.

Step (c1):
A coating liquid for forming an adhesive layer is applied to the surface of the second release film (manufactured by Panac Co., Ltd., Panapeel (registered trademark) SM-1, release film, PET thickness: 50 μm) on the release agent layer side. It was applied to a thickness of 25 μm using a coater. The coating film is dried at 100 ° C. for 1 minute to provide an anisotropic conductive adhesive layer (thickness: 10 μm, surface resistance: 1.0 E + 12 Ω or more Ω), and a second release film with an adhesive layer is provided. Obtained.

Step (c2):
In the laminate obtained in the step (b2), the carrier film was peeled off from the metal thin film layer to obtain a first release film with an insulating resin layer and a metal thin film layer.

Step (c3):
The first release film with the insulating resin layer and the metal thin film layer and the second release film with the adhesive layer are placed at 95 ° C. and 5 kPa so that the metal thin film layer and the anisotropic conductive adhesive layer are in contact with each other. Laminated under pressure to obtain an electromagnetically shielded film. At the time of adhesion by this lamination, if the adhesion was insufficient, the lamination treatment was performed again, and the number of times of lamination until sufficient adhesion was measured.

Step (d):
An insulating adhesive composition is applied to the surface of a polyimide film (insulating film body) having a thickness of 25 μm so that the dry film thickness becomes 25 μm to form an adhesive layer, and an insulating film (thickness: 50 μm) is applied. Obtained. A through hole (hole diameter: 150 μm) was formed at a position corresponding to the ground of the printed circuit.

A flexible printed wiring board in which a printed circuit was formed on the surface of a polyimide film (base film) having a thickness of 12 μm was prepared.
An insulating film was attached to the flexible printed wiring board by a hot press to obtain a flexible printed wiring board with an insulating film.

Step (e):
An electromagnetic wave shield film from which the second release film was peeled off was placed on a flexible printed wiring board with an insulating film, and a hot press device (G-12 manufactured by Orihara Seisakusho Co., Ltd.) was used to heat the hot plate temperature: 180 ° C. The anisotropic conductive adhesive layer was adhered to the surface of the insulating film by hot pressing for 1 minute.

Step (f):
The first release film was peeled off from the insulating resin layer to obtain a flexible printed wiring board with an electromagnetic wave shielding film. The obtained flexible printed wiring board with an electromagnetic wave shielding film was dried at 150 ° C. for 1 hour to cure the insulating resin layer and the anisotropic conductive adhesive layer.

<Evaluation>
A combustion test was carried out on the produced flexible printed wiring board with an electromagnetic wave shielding film by the following method. The results are shown in Table 1.
(Combustion test)
A gas burner flame was brought into contact with the lower end of the vertically held sample for 10 seconds, and the time during which the flexible printed wiring board with the electromagnetic wave shielding film continued to burn was measured. The shorter this time, the higher the flame retardancy.

(Comparative Example 1)
With an electromagnetic wave shielding film in the same manner as in Example 1 except that the phosphorus compound (M-Ester manufactured by Sanko Co., Ltd.) was not added to the coating liquid for forming the insulating resin layer and the coating liquid for forming the adhesive layer. A flexible printed wiring board was obtained. Similar to Example 1, a combustion test was carried out on a flexible printed wiring board with an electromagnetic wave shielding film. The results are shown in Table 1.

Since the electromagnetic wave shielding film of Example 1 contains the compound (1) in the insulating resin layer and the anisotropic conductive adhesive layer, the flame retardancy is improved. Further, during the production thereof, curling of the base film (release film) was suppressed by relaxing the shrinkage during curing, and sufficient adhesiveness to the metal thin film layer was obtained by the gentle laminating treatment. Further, since the anisotropic conductive adhesive layer contains the compound (2), when the release sheet is removed, the metal thin film layer and the anisotropic conductive adhesive layer are not peeled off at the adhesive surface. ..
Since the electromagnetic wave shielding film of Comparative Example 1 did not contain the compound (1), its flame retardancy was lower than that of Example 1. Further, at the time of its production, the base film was curled due to shrinkage during curing.
The above results show that the compound (1) not only functions as a flame retardant, but also functions as a low stress agent and an adhesive strength enhancer that suppress the curing shrinkage of the epoxy group-containing compound.

The electromagnetic wave shielding film of the present invention is useful as an electromagnetic wave shielding member in a flexible printed wiring board for electronic devices such as smartphones, mobile phones, optical modules, digital cameras, game machines, notebook computers, and medical appliances.

1 Electromagnetic wave shield film,
2 Flexible printed wiring board with electromagnetic wave shield film,
3 Flexible printed wiring board with insulating film,
10 Insulating resin layer,
22 metal thin film layer,
20 conductive layer,
24 anisotropic conductive adhesive layer,
24a Thermosetting composition (adhesive),
24b conductive particles,
26 Isotropic conductive adhesive layer,
26a Thermosetting composition (adhesive),
26b Conductive particles,
30 First release film,
32 base material layer,
34 Adhesive layer,
40 Second release film,
42 base material layer,
44 Release agent layer,
50 Flexible printed wiring board,
52 base film,
54 printed circuit,
60 Insulation film,
62 Through hole,
100 carrier film,
102 Base material layer,
104 Release agent layer.

Claims (8)

Insulating resin layer and
A metal thin film layer adjacent to the insulating resin layer and
With an adhesive layer adjacent to the side of the metal thin film layer opposite to the insulating resin layer
It is a manufacturing method of an electromagnetic wave shielding film having
The insulating resin is obtained by applying a thermosetting composition containing one or more of a compound represented by the following formula (1b-1) and an epoxy group-containing compound to the surface of the first release film and curing the composition. The step of obtaining the layered laminate A and
A step of obtaining the laminate B by forming the metal thin film layer on the surface of the insulating resin layer of the laminate A on the side opposite to the first release film.
By applying a thermosetting composition containing one or more of a compound represented by the following formula (1b-1) and an epoxy group-containing compound and conductive particles to the surface of the second release film and curing it. , The step of obtaining the laminate C on which the adhesive layer is formed, and
The surface of the adhesive layer of the laminate C is brought into contact with the surface of the exposed metal thin film layer of the laminate B to bring the insulating resin layer, the metal thin film layer, and the adhesive layer into contact with each other. this order is laminated, by applying heat and pressure applying lamination, it has a step of performing a contact bonding of the insulating resin layer and the metal thin film layer and the adhesive layer,
The laminating process is a process of heating at a temperature of 50 to 100 ° C. and pressurizing at 0.1 MPa or less.
Manufacturing method of electromagnetic wave shield film.

Insulating resin layer and
A metal thin film layer adjacent to the insulating resin layer and
With an adhesive layer adjacent to the side of the metal thin film layer opposite to the insulating resin layer
It is a manufacturing method of an electromagnetic wave shielding film having
The insulating resin is obtained by applying a thermosetting composition containing one or more of a compound represented by the following formula (1b-1) and an epoxy group-containing compound to the surface of the first release film and curing the composition. The step of obtaining the layered laminate A and
By applying a thermosetting composition containing one or more of a compound represented by the following formula (1b-1) and an epoxy group-containing compound and conductive particles to the surface of the second release film and curing it. , The step of obtaining the laminate C on which the adhesive layer is formed, and
A step of obtaining the laminate D by forming the metal thin film layer on the surface of the adhesive layer of the laminate C opposite to the second release film.
The surface of the insulating resin layer of the laminated body A is brought into contact with the surface of the exposed metal thin film layer of the laminated body D, and the insulating resin layer, the metal thin film layer, and the adhesive layer are brought into contact with each other. this order is laminated, by applying heat and pressure applying lamination, it has a step of performing a contact bonding of the insulating resin layer and the metal thin film layer and the adhesive layer,
The laminating process is a process of heating at a temperature of 50 to 100 ° C. and pressurizing at 0.1 MPa or less.
Manufacturing method of electromagnetic wave shield film.

Insulating resin layer and
A metal thin film layer adjacent to the insulating resin layer and
With an adhesive layer adjacent to the side of the metal thin film layer opposite to the insulating resin layer
It is a manufacturing method of an electromagnetic wave shielding film having
The metal thin film layer formed on the surface of the carrier film is prepared, and one of the compound represented by the following formula (1b-1) and the epoxy group-containing compound is prepared on the surface of the metal thin film layer opposite to the carrier film. A step of obtaining a laminate E on which the insulating resin layer is formed by applying a thermosetting composition containing seeds or more and curing the composition.
The adhesion is achieved by applying a thermosetting composition containing one or more of a compound represented by the following formula (1b-1), an epoxy group-containing compound, and conductive particles to the surface of the release film and curing the composition. The step of obtaining the laminate C on which the agent layer is formed, and
The carrier film of the laminated body E is peeled off, and the surface of the adhesive layer of the laminated body C is brought into contact with the exposed surface of the metal thin film layer to obtain the insulating resin layer and the metal thin film layer. the an adhesive layer laminated in this order, by performing the heating and pressurizing lamination, have a step of performing a contact bonding of the insulating resin layer and the metal thin film layer and the adhesive layer,
The laminating process is a process of heating at a temperature of 50 to 100 ° C. and pressurizing at 0.1 MPa or less.
Manufacturing method of electromagnetic wave shield film.

The method for producing an electromagnetic wave shielding film according to any one of claims 1 to 3, further comprising a black colorant in the thermosetting composition forming the insulating resin layer. Claims 1 to 1 further include, in the thermosetting composition forming at least one of the insulating resin layer and the adhesive layer, one or more selected from the group of compounds represented by the following formula (2). The method for producing an electromagnetic wave shielding film according to any one of 4.

[In the formula, L1 and L2 are independently single-bonded or divalent linking groups having 1 to 8 carbon atoms, m and n are independently integers of 1 to 5, and m + n is 2 to 6. , Any one or more hydrogen atoms bonded to the benzene ring are substituted with (HO-L1-) groups, and any other one or more hydrogen atoms are (-L2-COOH). Any one or more hydrogen atoms substituted with groups and not substituted with (HO-L1-) and (-L2-COOH) groups may be substituted with any substituent. ] A printed wiring board with a printed circuit on at least one side of the board,
An insulating film adjacent to the surface of the printed wiring board on the side where the printed circuit is provided is provided.
An adhesive layer of the electromagnetic wave shielding film is provided so as to be adjacent to the insulating film.
It is a method of manufacturing a printed wiring board with an electromagnetic wave shield film.
A step of obtaining an electromagnetic wave shielding film by the manufacturing method according to any one of claims 1 to 5.
A crimping step of adhering the adhesive layer to the surface of the insulating film by stacking the adhesive layer of the electromagnetic wave shielding film on the surface of the insulating film of the printed wiring plate so as to be in contact with each other and crimping them. When,
A method for manufacturing a printed wiring board with an electromagnetic wave shielding film. The method for manufacturing a printed wiring board with an electromagnetic wave shielding film according to claim 6 , wherein when crimping in the crimping step, the insulating resin layer and the adhesive layer are pressed while being heated. The print with an electromagnetic wave shielding film according to claim 6 or 7 , further comprising a curing step of curing the thermosetting composition by further heating the insulating resin layer and the adhesive layer after the crimping step. How to manufacture a wiring board.

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