CN110809394A - Electromagnetic wave shielding film and manufacturing method thereof, and printed wiring board with electromagnetic wave shielding film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an electromagnetic wave shielding film and a manufacturing method thereof, as well as a printed wiring board with the electromagnetic wave shielding film and a manufacturing method thereof. Provided are an electromagnetic wave shielding film in which the adhesion between an insulating resin layer and a conductive layer is sufficiently improved, and a method for producing the same. The electromagnetic wave shielding film (1) of the present invention has an insulating resin layer (10) and a conductive layer (20) containing a metal adjacent to the insulating resin layer (10), and the insulating resin layer (10) contains aromatic polyether ketone and polyether imide. The above-mentioned aromatic polyetherketone may be polyetheretherketone or polyetherketoneketone. The above-mentioned polyetherimide may be a polyetherimide having a glass transition temperature of 200° C. or higher and a repeating unit represented by a specific chemical formula.

Description

Electromagnetic wave shielding film, method for producing the same, and printing with electromagnetic wave shielding film Circuit board and method of making the same

technical field

The present invention relates to an electromagnetic wave shielding film and a manufacturing method thereof, as well as a printed wiring board with the electromagnetic wave shielding film and a manufacturing method thereof.

Background technique

In order to shield electromagnetic noise generated by the printed wiring board and electromagnetic noise from the outside, an insulating resin layer and a conductive layer adjacent to the insulating resin layer are sometimes provided on the surface of the printed wiring board through an insulating film (coverlay film). The electromagnetic wave shielding film (for example, refer to Patent Document 1).

The electromagnetic wave shielding film is produced, for example, by applying a coating containing a thermosetting resin, a curing agent and a solvent to one side of a carrier film, drying it to form an insulating resin layer, and providing a conductive layer on the surface of the insulating resin layer. The conductive layer is formed of at least one of a metal thin film layer and an adhesive layer (eg, a conductive adhesive layer).

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2016-86120

SUMMARY OF THE INVENTION

The technical problem to be solved by the invention

A conventional insulating resin layer formed of a thermosetting resin has low adhesiveness to a conductive layer containing a metal. In particular, when the conductive layer has a metal thin film layer and the metal thin film layer is in contact with the insulating resin layer, the adhesiveness is particularly low. Therefore, in the conventional electromagnetic wave shielding film, the adhesive force between the insulating resin layer and the conductive layer is weak, and interlayer peeling may occur in the process of handling the electromagnetic wave shielding film. For example, when the carrier film is peeled off from the insulating resin layer, the insulating resin layer is sometimes peeled off from the conductive layer together with the carrier film.

The objective of this invention is to provide the electromagnetic wave shielding film which can fully improve the adhesive force of the conductive layer containing a metal, and an insulating resin layer, and its manufacturing method.

technical solutions for problem solving

The present invention includes the following aspects.

[1] An electromagnetic wave shielding film comprising an insulating resin layer containing an aromatic polyetherketone and a polyetherimide, and a conductive layer containing a metal adjacent to the insulating resin layer.

[2] The electromagnetic wave shielding film according to [1], wherein the aromatic polyetherketone is polyetheretherketone or polyetherketoneketone.

[3] The electromagnetic wave shielding film according to [1] or [2], wherein the polyetherimide has a glass transition temperature of 200° C. or higher, and has a repeating unit represented by the following chemical formula (A);

[hua 1]

[4] The electromagnetic wave shielding film according to any one of [1] to [3], wherein the content of the aromatic polyetherketone is 5 mass % or more and 95 mass % with respect to the total mass of the insulating resin layer % or less, and content of the said polyetherimide is 5 mass % or more and 95 mass % or less.

[5] The electromagnetic wave shielding film according to any one of [1] to [4], wherein the insulating resin layer has a thickness of 2 μm or more and 10 μm or less.

[6] The electromagnetic wave shielding film according to any one of [1] to [5], wherein the conductive layer is a metal vapor deposition layer.

[7] The electromagnetic wave shielding film according to [6], wherein the metal vapor deposition layer is a silver vapor deposition layer or a copper vapor deposition layer.

[8] The electromagnetic wave shielding film according to any one of [1] to [7], further comprising a carrier film on the surface of the insulating resin layer opposite to the conductive layer.

[9] A printed wiring board with an electromagnetic wave shielding film, comprising: a printed wiring board provided with a printed circuit on at least one side of a substrate; one side is adjacent to each other; and, the electromagnetic wave shielding film according to any one of [1] to [8], which is provided so that the conductive layer and the insulating film are adjacent to each other.

[10] A method for producing an electromagnetic wave shielding film, comprising the steps of: molding a mixed resin of aromatic polyetherketone and polyetherimide into a film shape, forming an insulating resin layer, and forming an insulating resin layer on one side of the insulating resin layer. A conductive layer is formed on the side.

[11] A method for producing a printed wiring board with an electromagnetic wave shielding film, comprising the steps of: combining a printed wiring board with a printed circuit on at least one side of a substrate and any one of [1] to [8] The electromagnetic wave shielding film described in the item is crimped with an insulating film interposed therebetween.

effect of invention

The electromagnetic wave shielding film of this invention can fully improve the adhesive force of the conductive layer containing a metal, and an insulating resin layer.

According to the manufacturing method of the electromagnetic wave shielding film of this invention, the said electromagnetic wave shielding film can be manufactured easily.

In the printed wiring board with the electromagnetic wave shielding film of the present invention, the adhesion between the conductive layer containing metal and the insulating resin layer is sufficiently high.

According to the manufacturing method of the printed wiring board with an electromagnetic wave shielding film of this invention, the said printed wiring board with an electromagnetic wave shielding film can be manufactured easily.

Description of drawings

FIG. 1 is a cross-sectional view showing a first embodiment of the electromagnetic wave shielding film of the present invention.

2 is a cross-sectional view showing a second embodiment of the electromagnetic wave shielding film of the present invention.

3 is a cross-sectional view showing a third embodiment of the electromagnetic wave shielding film of the present invention.

4 is a cross-sectional view showing one embodiment of the electromagnetic wave shielding film-equipped printed wiring board of the present invention.

5 is a cross-sectional view illustrating a manufacturing process of the electromagnetic wave shielding film-equipped printed wiring board of FIG. 4 .

Detailed ways

The definitions of the following terms apply to the full scope of this specification and claims.

The "isotropic conductive adhesive layer" refers to a conductive adhesive layer having conductivity in the thickness direction and the surface direction.

The "anisotropic conductive adhesive layer" means a conductive adhesive layer that has conductivity in the thickness direction and does not have conductivity in the surface direction.

The "conductive adhesive layer without conductivity in the plane direction" refers to a conductive adhesive layer having a surface resistance of 1×10 ⁴ Ω or more.

The average particle diameter of the particles is a value obtained by randomly selecting 30 particles from a microscope image of the particles, measuring the minimum diameter and the maximum diameter of each particle, and taking the median value of the minimum diameter and the maximum diameter as the particle diameter of one particle , the average particle diameter of the particles is obtained by arithmetically averaging the particle diameters of the 30 particles measured. The same applies to the average particle diameter of the conductive particles.

The cross section of the object to be measured is observed with a microscope, the thickness of 5 places is measured and averaged, and the obtained value is the film (release film, insulating film, etc.), coating film (insulating resin layer, conductive adhesive layer, etc.), metal Thickness of film layers, etc.

The storage modulus was calculated from the stress applied to the measurement object and the detected strain, and was measured as one of the viscoelastic properties using a dynamic viscoelasticity measuring device that outputs as a function of temperature or time.

The tensile modulus was determined by measurement using a tensile tester based on JIS K7127. It is a value obtained by dividing the tensile stress received by the measurement object by the strain generated by the measurement object within the elastic limit, and has the same meaning as Young's modulus.

The 10% compressive strength of the electroconductive particles was determined by the following formula (α) from the measurement results using a micro-compression tester.

C(x)=2.48P/πd ² (α)

Among them, C(x) is the 10% compressive strength (MPa), P is the test force (N) when the particle size is displaced by 10%, and d is the particle size (mm).

Surface resistance refers to the resistance measured as follows: using two thin-film metal electrodes (length 10mm, width 5mm, distance between electrodes 10mm) formed by vapor deposition of gold on quartz glass, the object to be measured is placed on the electrodes, The resistance between the electrodes was measured by pressing a 10 mm×20 mm area of the object to be measured above the object to be measured with a load of 0.049 N, and measuring the resistance between the electrodes with a measurement current of 1 mA or less.

For convenience of description, the size ratios in FIGS. 1 to 5 are different from the actual size ratios.

＜Electromagnetic wave shielding film＞

A first aspect of the present invention is an electromagnetic wave shielding film including an insulating resin layer containing an aromatic polyether ketone and a polyetherimide, and a conductive layer containing a metal adjacent to the insulating resin layer.

1 is a cross-sectional view showing the electromagnetic wave shielding film 1 according to the first embodiment, FIG. 2 is a cross-sectional view showing the electromagnetic wave shielding film 1 according to the second embodiment, and FIG. 3 is a cross-sectional view showing the electromagnetic wave shielding film 1 according to the third embodiment. .

The electromagnetic wave shielding films 1 of the first embodiment, the second embodiment, and the third embodiment all have an insulating resin layer 10 , a conductive layer 20 adjacent to the insulating resin layer 10 , and the opposite side of the insulating resin layer 10 to the conductive layer 20 . The adjacent carrier film 30 and the release film 40 adjacent to the side opposite to the insulating resin layer 10 of the conductive layer 20 are provided.

In the electromagnetic wave shielding film 1 of the first embodiment, the conductive layer 20 includes the metal thin film layer 22 adjacent to the insulating resin layer 10 and the anisotropic conductive adhesive layer 24 adjacent to the release film 40 .

In the electromagnetic wave shielding film 1 of the second embodiment, the conductive layer 20 includes the metal thin film layer 22 adjacent to the insulating resin layer 10 and the isotropic conductive adhesive layer 26 adjacent to the release film 40 .

In the electromagnetic wave shielding film 1 of the third embodiment, the conductive layer 20 includes the isotropic conductive adhesive layer 26 .

(insulating resin layer)

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 carrier film 30 is peeled off, the insulating resin layer 10 becomes a protective layer of the conductive layer 20 .

The insulating resin layer 10 contains aromatic polyetherketone and polyetherimide.

The aromatic polyether ketone is a polymer having a structure in which benzene rings are bonded to each other via ether bonds, and a structure in which benzene rings are bonded to each other via a ketone group.

The polyetherimide is a polymer having a structure in which aromatic rings are bonded to each other through ether bonds, and a structure in which aromatic rings are bonded to each other through imide bonds.

Examples of the aromatic polyether ketone include polyether ether ketone (PEEK) having a chemical structure represented by chemical formula (1), polyether ketone (PEK) having a chemical structure represented by chemical formula (2), Polyetherketoneketone (PEKK) having a chemical structure represented by chemical formula (3), polyetheretherketoneketone (PEEKK) having a chemical structure represented by chemical formula (4), and polyether having a chemical structure represented by chemical formula (5) Ketone ether ketone ketone (PEKEKK). The aromatic polyether ketone contained in the insulating resin layer 10 may be one kind alone or two or more kinds.

In addition, the aromatic polyether ketone may be a copolymer having two or more chemical structures among the chemical structures represented by chemical formulae (1) to (5).

Both ends of the aromatic polyether ketone represented by chemical formulae (1) to (5) are hydrogen atoms.

[hua 2]

Among the above-mentioned aromatic polyetherketones, PEEK is preferable from the viewpoint of easy formation of the insulating resin layer 10 and further improvement of the adhesiveness to the metal thin film layer 22 .

From the viewpoint of mechanical properties, n in each of the chemical formulae (1) to (5) above is preferably 10 or more, and more preferably 20 or more. On the other hand, since the aromatic polyether ketone can be easily produced, n is preferably 5000 or less, and more preferably 1000 or less. That is, 10 or more and 5000 or less are preferable, and 20 or more and 1000 or less are more preferable.

The aromatic polyether ketone may be a block copolymer, a random copolymer, or a modified product of other copolymerizable monomers such as ether sulfone within the range not impairing the effects of the present invention.

In the aromatic polyether ketone, the ratio of the repeating unit of the polyether ketone represented by any one of the above-mentioned chemical formulae (1) to (5) is 50 mol % or more and 100 mol with respect to 100 mol % of the aromatic polyether ketone % or less, more preferably 70 mol % or more and 100 mol % or less, further preferably 80 mol % or more and 100 mol % or less, and most preferably 100 mol %. In the aromatic polyether ketone, when the ratio of the repeating unit of the said aromatic polyether ketone is more than the said lower limit, the adhesive force of the insulating resin layer 10 and the conductive layer 20 can be further strengthened.

Methods for producing aromatic polyetherketones are disclosed in, for example, JP 50-27897 A, JP 51-119797 A, JP 52-38000 A, and JP 54-90296 A , Japanese Patent Publication No. 55-23574, Japanese Patent Publication No. 56-2091.

Examples of commercial products of PEEK include Victrex Peek series (product name) manufactured by Victrex, Vestakeep series (product name) manufactured by Daicel Evonik, KetaSpire polyetheretherketone series (product name) manufactured by Solvay Specialty Polymers product name).

As the polyetherimide (PEI) constituting the insulating resin layer 10 , for example, PEI having a glass transition temperature of 200° C. or higher is preferable. As PEI whose glass transition temperature is 200 degreeC or more, PEI which has a repeating unit represented by following chemical formula (A) is mentioned, for example.

[hua 3]

PEI having a repeating unit represented by the following chemical formula (B) may be added to PEI having a repeating unit represented by the above-mentioned chemical formula (A) within a range not impairing the effects of the present invention.

[hua 4]

As a specific example of PEI which has the repeating unit of the said chemical formula (A), ULTEM 1010-1000-NB, ULTEM 9011-1000-NB [all SABIC INNOVATIVE PLASTICS company, a product name] etc. are mentioned. As a manufacturing method of PEI which has the repeating unit of the said chemical formula (A), for example, 4,4'-isopropylidene bis (p-phenyleneoxy) diphthalic anhydride and m-phenylenediamine are mentioned. known methods of polycondensation.

As a specific example of PEI which has the repeating unit of the said chemical formula (B), ULTEM CRS5001-1000-NB [SABIC INNOVATIVE PLASTICS company product name] is mentioned. As a method for producing PEI having a repeating unit of the above-mentioned chemical formula (B), for example, polycondensation of 4,4'-isopropylidenebis(p-phenyleneoxy)diphthalic acid and p-phenylenediamine can be mentioned. known method.

The polyetherimide constituting the insulating resin layer 10 may be a block copolymer, a random copolymer, or a modified product of other copolymerizable monomers such as an amide group, an ester group, a sulfonyl group, and a siloxane group. These include, for example, ULTEM XH6050-1000 [SABIC INNOVATIVE PLASTICS Co., Ltd. trade name] with a glass transition temperature of 238°C as a polyetherimide sulfone copolymer, and a polyetherimide/siloxane copolymer ULTEM STM1700-1000 [ SABIC INNOVATIVE PLASTICS company product name] and so on.

Since PEI having the repeating unit of the above-mentioned chemical formula (A) and PEEK having the repeating unit of the above-mentioned chemical formula (1) are very excellent in compatibility, it is preferable to form the insulating resin layer 10 from a mixed resin in which these are combined.

Among the resin components constituting the insulating resin layer 10, PEEK having the repeating unit represented by the above chemical formula (1) and PEI having the repeating unit represented by the above chemical formula (A) and having a glass transition temperature of 200° C. or higher are preferably: In terms of composition mass ratio, PEEK is 5 mass % or more and 95 mass % or less, and polyetherimide resin is 5 mass % or more and 95 mass % or less. Here, it is more preferable that PEEK is 10 mass % or more and 90 mass % or less, and the polyetherimide resin is 10 mass % or more and 90 mass % or less, and it is more preferable that PEEK is 20 mass % or more and 80 mass % or less, and the polyetherimide resin is more preferably 20 mass % or more and 80 mass % or less. The etherimide resin is 20% by mass or more and 80% by mass or less.

When it is more than the lower limit of the said range, the heat resistance is further excellent, and when it is below the upper limit of the said range, the adhesiveness of the insulating resin layer 10 with respect to the conductive layer 20 is more excellent.

The glass transition temperature (glass transition temperature: Tg) of the resin constituting the insulating resin layer 10 varies according to the mixing ratio of the above-mentioned PEEK and the above-mentioned PEI. The higher the ratio of PEI to PEEK, the higher the Tg of the insulating resin layer 10 tends to be. When the Tg of the above-mentioned resin is high, it is less susceptible to the influence of the heat treatment at the time of producing the electromagnetic wave shielding film and the influence of the high temperature environment at the time of use, which is preferable. As Tg of the said resin, 140-210 degreeC is preferable, 165-205 degreeC is more preferable, and 170-200 degreeC is still more preferable. When it is more than the lower limit of the said range, generation|occurrence|production of wrinkles, waves, local melting, etc. on the surface of the insulating resin layer 10 by heat processing at the time of manufacture of an electromagnetic wave shielding film can be prevented. Adhesion to the metal thin film 22 can be further improved as it is below the upper limit of the said range.

As a method of forming the insulating resin layer 10 from a mixed resin of aromatic polyether ketone and PEI, for example, a method of melt-kneading aromatic polyether ketone and PEI with an extruder to prepare a molding material, The molding material is continuously extruded to form an insulating resin layer. Hereinafter, the case where the aromatic polyether ketone is PEEK will be described, but the same can be done in the case of an aromatic polyether ketone other than PEEK.

The preparation methods of PEEK and PEI include, for example, the following methods: (a) a method for preparing a molding material by stirring and mixing PEEK and PEI particles at 0 to 50° C., respectively, followed by melt-kneading; (b) PEI is added to molten PEEK, and these are melt-kneaded to prepare a molding material; or, PEEK is added to molten PEI, and these are melt-kneaded to prepare a molding material. From the viewpoint of improving dispersibility, the method of (a) is preferred.

The production method of the above (a) will be further described. For the stirring and mixing of PEEK and PEI, a drum mixer, a Henschel mixer, a V-type mixer, a Nauta mixer, a ribbon mixer, a universal mixer, or the like are used. In addition, the above-mentioned agitated mixture was mixed with a mixing roll, a pressure kneader, a single-screw extruder, a twin-screw extruder, a three-screw extruder, a four-screw extruder, and an eight-screw extruder. PEEK and PEI can be dispersed by melting and kneading in a melt-kneader such as a multi-screw extruder.

The temperature at which PEEK and PEI are melt-kneaded may be the melting point of PEEK or higher or the glass transition temperature of PEI or higher and 450°C or lower, preferably 350°C or higher and 430°C or lower. When the melt-kneading temperature is equal to or higher than the lower limit value of the above range, PEEK and PEI can be more uniformly dispersed. When it is below the upper limit of the said range, thermal decomposition of PEEK or PEI can be suppressed.

The production method of the above (b) will be further described. Any one of PEEK or PEI is prepared by mixing rollers, pressure kneaders, single-screw extruders, two-screw extruders, three-screw extruders, four-screw extruders, and eight-screw extruders. After being melted from a melt-kneading machine such as a multi-screw extruder such as a molding machine, another unmelted resin can be added, melted, and kneaded, thereby enabling dispersion. The temperature of this melt-kneading is preferably the same temperature range as the above (a).

The insulating resin layer 10 can be formed by a known molding method such as a melt extrusion molding method, a calender molding method, or a tape casting method using a mixed resin composed of a mixed resin of PEEK and PEI.

The insulating resin layer 10 may contain other resins in addition to the aromatic polyether ketone and PEI. Examples of other resins include polyimide (PI), polyamideimide (PAI), polyamide 6T (PA6T), modified polyamide 6T (modified PA6T), polyamide 9T (PA9T), polyamide Amide 10T (PA10T), Polyamide 11T (PA11T), Polyamide 6 (PA6), Polyamide 66 (PA66), Polyamide 46 (PA46), Polysulfone (PSU), Polyethersulfone (PES), Polyphenylsulfone (PPSU), polyphenylene sulfide (PPS), polyphenylene sulfide ketone, polyphenylene sulfide sulfone, polyphenylene sulfide ketone sulfone, liquid crystal polymer (LCP), and the like.

With respect to the total mass of the insulating resin layer 10 , the content of the aromatic polyetherketone is preferably 5% by mass or more and 95% by mass or less, and the content of PEI is preferably 5% by mass or more and 95% by mass or less. Moreover, it is more preferable that the content of the aromatic polyether ketone is 10 mass % or more and 90 mass % or less, and the PEI content is 10 mass % or more and 90 mass % or less.

When it is more than the lower limit of the said range, the heat resistance is further excellent, and when it is below the upper limit of the said range, the adhesiveness of the insulating resin layer 10 with respect to the conductive layer 20 is more excellent.

When the tensile modulus at 160° C. of the insulating resin layer 10 is high, it is less likely to be affected by the heat treatment at the time of production of the electromagnetic wave shielding film or by the high temperature environment at the time of use, which is preferable. The tensile modulus is preferably 1000 N/mm ² to 5000 N/mm ² , more preferably 1500 N/mm ² to 4000 N/mm ² , and still more preferably 2000 N/mm ² to 3000 N/mm ² . When it is more than the lower limit of the said range, generation|occurrence|production of a wrinkle, a waviness, a local break, etc. in the insulating resin layer 10 by heat processing at the time of manufacture of an electromagnetic wave shielding film can be prevented. When it is below the upper limit of the said range, the balance of the tensile modulus with other layers becomes more favorable, and the adhesiveness with respect to the metal thin film 22 can be improved more.

The insulating resin layer 10 may contain any one or both of colorants (pigments, dyes, etc.) and fillers in order to conceal the printed circuit of the printed wiring board or to impart designability to the printed wiring board with the electromagnetic wave shielding film.

As either or both of the colorant and filler, from the viewpoint of weather resistance, heat resistance, and concealment, a pigment or a filler is preferable, and from the viewpoint of concealment and design property of a printed circuit, a black pigment, or Combinations of black pigments with other pigments or fillers.

The insulating resin layer 10 may contain antioxidants, light stabilizers, ultraviolet stabilizers, plasticizers, lubricants, flame retardants, antistatic agents, heat resistance improvers, inorganic Additives such as fillers and organic fillers.

From the viewpoint of electrical insulating properties, the surface resistance of the insulating resin layer 10 is preferably 1×10 ⁶ Ω or more. From a practical standpoint, the surface resistance of the insulating resin layer 10 is preferably 1×10 ¹⁹ Ω or less.

The thickness of the insulating resin layer 10 is preferably 2.0 μm or more and 30 μm or less, and more preferably 3.0 μm or more and 10 μm or less. If the thickness of the insulating resin layer 10 is equal to or more than the lower limit value of the above-mentioned range, the insulating resin layer 10 can sufficiently function as a protective layer. If the thickness of the insulating resin layer 10 is equal to or less than the upper limit of the above-mentioned range, the electromagnetic wave shielding film 1 can be thinned.

(conductive layer)

The conductive layer has at least a metal-containing conductive adhesive layer. The metal may be in the form of a film, may be in the form of particles, or may be in other shapes.

Specifically, as described above, the conductive layer 20 in the first embodiment includes the metal thin film layer 22 adjacent to the insulating resin layer 10 and the anisotropic conductive adhesive layer 24 adjacent to the release film 40 .

The conductive layer 20 in the second embodiment has the metal thin film layer 22 adjacent to the insulating resin layer 10 and the isotropic conductive adhesive layer 26 adjacent to the release film 40 .

The conductive layer 20 in the third embodiment includes an isotropic conductive adhesive layer 26 .

The conductive layer 20 preferably has a metal thin film layer 22 and an anisotropic conductive adhesive layer 24 or an isotropic conductive adhesive layer 26 from the viewpoint of sufficiently high electromagnetic wave shielding properties. That is, the conductive layer 20 preferably has two layers, the metal thin film layer and the conductive adhesive layer.

[Metal thin film layer]

The metal thin film layer 22 is a layer containing a thin film of metal. 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 shielding layer or the like.

Examples of the metal thin film layer 22 include a vapor-deposited film formed by physical vapor deposition (vacuum vapor deposition, sputtering, ion beam vapor deposition, electron beam vapor deposition, etc.) or chemical vapor deposition, a plated film formed by plating, Metal foil, etc. The conductive layer 20 is preferably a vapor-deposited film or a plated film from the viewpoint of excellent conductivity in the plane direction. The conductive layer 20 is more preferably a vapor-deposited film, more preferably a vapor-deposited film formed by physical vapor deposition, since the conductive layer 20 can be thinned, has excellent electrical conductivity in the plane direction even with a small thickness, and can be easily formed by a dry process. Coating.

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

Among the metal thin film layers 22, a metal vapor-deposited layer is preferable, and a silver vapor-deposited layer or a copper vapor-deposited layer is more preferable because the electromagnetic wave shielding property is high and the metal thin film layer is easily formed.

The surface resistance of the metal thin film layer 22 is preferably 0.001Ω or more and 1Ω or less, and more preferably 0.001Ω or more and 0.5Ω or less. If the sheet resistance of the metal thin film layer 22 is equal to or more than the lower limit value of the above-mentioned range, the metal thin film layer 22 can be sufficiently thinned. If the surface resistance of the metal thin film layer 22 is equal to or less than the upper limit of the above-mentioned range, the function of the electromagnetic wave shielding layer can be sufficiently exerted.

The thickness of the metal thin film layer 22 is preferably 0.01 μm or more and 5 μm or less, and more preferably 0.05 μm or more and 3 μm or less. When the thickness of the metal thin film layer 22 is 0.01 μm or more, the electrical 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. If the thickness of the metal thin film layer 22 is equal to or less than the upper limit of the above-mentioned 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.

[blackened layer]

The metal thin film layer 22 such as the silver vapor deposition layer and the copper vapor deposition layer has high light reflectivity and metallic luster. In order to suppress this metallic luster, the conductive layer 20 may have a blackened layer on the surface of the metal thin film layer 22 on the insulating resin layer 10 side. For example, when the electromagnetic wave shielding film 1 is used in a flexible printed wiring board for a display, in order to prevent the gloss of the metal thin film layer 22 from affecting the visibility of the display, it is preferable to provide blackening between the metal thin film layer 22 and the insulating resin layer 10 Floor.

The blackened layer is a black layer made of a light absorbing material and having anti-light reflection properties. Specifically, the blackened layer preferably has a luminance L ^* defined in JISZ8781-5 of 5 or less. The smaller the value of the luminance L ^* , the greater the blackness and the tendency to suppress light reflection.

The blackened layer is composed of, for example, any one of the light-absorbing materials in the following (i) to (iii).

(i) Silver oxide or copper oxide

(ii) at least one selected from the group consisting of copper nitride, copper oxide, nickel nitride, and nickel oxide

(iii) any one of zinc, copper and zinc alloy, silver and zinc alloy

When the blackened layer is composed of the above (i), a method of forming a layer containing an oxide of silver or an oxide of copper by vapor deposition or plating is exemplified. As a vapor deposition method, a well-known vapor deposition method, such as a vacuum vapor deposition method and a sputtering method, can be used, for example.

When the blackened layer is composed of the above (ii), a layer containing at least one selected from the group consisting of copper nitride, copper oxide, nickel nitride, and nickel oxide is formed by vapor deposition or plating. Methods.

When the blackened layer is composed of the above-mentioned (iii), a method of forming a layer including any one of zinc, copper and zinc alloy, and silver and zinc alloy by vapor deposition or plating is exemplified.

The thickness of the blackened layer is not particularly limited, but is preferably 5 nm or more and 20 μm or less, and more preferably 10 nm or more and 1 μm or less. When the thickness of the blackened layer is equal to or more than the above lower limit value, light reflection can be sufficiently suppressed, and if it is equal to or less than the above upper limit value, the blackened layer can be easily formed.

[Anisotropic Conductive Adhesive Layer]

The anisotropic conductive adhesive layer 24 in the first embodiment has electrical conductivity in the thickness direction, but has no electrical conductivity in the surface direction, and has adhesiveness.

The anisotropic conductive adhesive layer 24 can easily reduce the thickness of the conductive adhesive layer, and can reduce the amount of conductive particles described later. As a result, the electromagnetic wave shielding film 1 can be thinned and the flexibility of the electromagnetic wave shielding film 1 can be improved. the advantages of sex.

The anisotropic conductive adhesive layer 24 is preferably a thermosetting conductive adhesive layer from the viewpoint of exhibiting heat resistance after curing. The thermosetting anisotropic conductive adhesive layer 24 may be in an uncured state or in a B-staged state.

The thermosetting anisotropic conductive adhesive layer 24 contains, for example, a thermosetting adhesive 24a and conductive particles 24b. The anisotropic conductive adhesive layer 24 may contain a flame retardant as needed.

As the thermosetting adhesive 24a, epoxy resin, phenol resin, amino resin, alkyd resin, polyurethane resin, synthetic rubber, ultraviolet curing acrylate resin, etc. are mentioned. From the viewpoint of being excellent in heat resistance, epoxy resins are preferred. The epoxy resin may contain a rubber component (carboxy-modified nitrile rubber, acrylic rubber, etc.) for imparting flexibility, a tackifier, and the like.

In order to increase the strength of the anisotropic conductive adhesive layer 24 and improve the punching properties, the thermosetting adhesive 24a may contain cellulose resin, microfibers (glass fibers, etc.). The said thermosetting adhesive may contain other components in the range which does not impair the effect of this invention as needed.

Examples of the conductive particles 24b include metal (silver, platinum, gold, copper, nickel, palladium, aluminum, solder, etc.) particles, graphite powder, sintered carbon particles, plated sintered carbon particles, and the like. As the conductive particles 24b, metal particles are preferable because the anisotropic conductive adhesive layer 24 has a more suitable hardness and the pressure loss of the anisotropic conductive adhesive layer 24 during hot pressing can be further reduced. , more preferably copper particles.

The 10% compressive strength of the conductive particles 24b is preferably 30 MPa or more and 200 MPa or less, more preferably 50 MPa or more and 150 MPa or less, and further preferably 70 MPa or more and 100 MPa or less. If the 10% compressive strength of the conductive particles is at least the lower limit of the above range, the pressure loss applied to the metal thin film layer 22 during hot pressing will not be too large, and the anisotropic conductive adhesive layer 24 will pass through the The through hole of the insulating film is more reliably electrically connected to the printed circuit of the printed wiring board. When the 10% compressive strength of the electroconductive particles 24b is equal to or less than the upper limit value of the above-mentioned range, the contact with the metal thin film layer 22 becomes favorable, and the electrical connection becomes reliable.

The average particle diameter of the conductive particles 24b in the anisotropic conductive adhesive layer 24 is 2 μm or more and 26 μm or less, and more preferably 4 μm or more and 16 μm or less. If the average particle diameter of the electroconductive particle 24b is more than the lower limit of the said range, the thickness of the anisotropic electroconductive adhesive bond layer 24 can be ensured, 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-mentioned range, the fluidity of the anisotropic conductive adhesive layer 24 can be ensured. When the layer 24 is pressed into the through hole of the insulating film, the inside of the through hole of the insulating film can be sufficiently filled with the conductive adhesive.

The ratio 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 in 100% by volume of the anisotropic conductive adhesive layer 24, and more It is preferably not less than 2% by volume and not more than 15% by volume. The electroconductivity of the anisotropic conductive adhesive bond layer 24 becomes favorable as the ratio of the electroconductive particle 24b is more than the lower limit of the said range. When the ratio of the conductive particles 24b is equal to or less than the upper limit of the above-mentioned range, the adhesiveness and fluidity of the anisotropic conductive adhesive layer 24 (the conformability to the shape of the through-holes in the insulating film) will be favorable. . Moreover, the flexibility of the electromagnetic wave shielding film 1 becomes favorable.

The storage modulus at 180° C. of the anisotropic conductive adhesive layer 24 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 the following. When the storage modulus at 180° C. of the anisotropic conductive adhesive layer 24 is equal to or more than the lower limit value of the above-mentioned range, the anisotropic conductive adhesive layer 24 has a more suitable hardness, and the hot pressing can be reduced. pressure loss on the conductive adhesive layer. As a result, the conductive adhesive layer and the printed circuit of the printed wiring board are sufficiently bonded, and the anisotropic conductive adhesive layer 24 is more reliably electrically connected to the printed circuit of the printed wiring board through the through holes of the insulating film. The flexibility of the electromagnetic wave shielding film 1 becomes favorable as the storage elastic modulus in 180 degreeC of a conductive adhesive layer is below the upper limit of the said range. As a result, the electromagnetic wave shielding film 1 easily sinks into the through holes of the insulating film, and the anisotropic conductive adhesive layer 24 is more reliably electrically connected to the printed circuit of the printed wiring board via the through holes of the insulating film.

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. If the surface resistance of the anisotropic conductive adhesive bond layer 24 is more than the lower limit of the said range, content of the electroconductive particle 24b can be controlled low.

If the surface resistance of the anisotropic conductive adhesive layer 24 is equal to or less than the upper limit value of the above-mentioned range, there is no problem in terms of anisotropy in practical use.

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 more than the lower limit value of the above-mentioned range, the fluidity of the anisotropic conductive adhesive layer 24 (the conformability to 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. If the thickness of the anisotropic conductive adhesive layer 24 is equal to or less than the upper limit of the above-mentioned range, the electromagnetic wave shielding film 1 can be thinned. Moreover, the flexibility of the electromagnetic wave shielding film 1 becomes favorable.

[Isotropic Conductive Adhesive Layer]

The isotropic conductive adhesive layer 26 in the second embodiment or the third embodiment has electrical conductivity in the thickness direction and the surface direction, and has adhesiveness.

The isotropic conductive adhesive layer 26 has an advantage that the electromagnetic wave shielding property of the electromagnetic wave shielding film 1 can be further improved.

As the isotropic conductive adhesive layer 26, a thermosetting conductive adhesive layer is preferable from the viewpoint of exhibiting heat resistance after curing. The thermosetting isotropic conductive adhesive layer 26 may be in an uncured state or in a B-staged state.

The thermosetting isotropic conductive adhesive layer 26 contains, for example, a thermosetting adhesive 26a and conductive particles 26b. The thermosetting isotropic conductive adhesive layer 26 may contain a flame retardant as necessary.

The components of the thermosetting adhesive 26a contained in the isotropic conductive adhesive layer 26 and the material of the conductive particles 26b, and the components of the thermosetting adhesive 24a contained in the anisotropic conductive adhesive layer 24 and conductive particles The material of the sexual particles 24b is the same.

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. If the average particle diameter of the electroconductive particle 26b is more than the lower limit of the said range, the number of contact points of the electroconductive particle 26b will increase, and the conductivity in a three-dimensional direction can be improved stably. When the average particle diameter of the conductive particles 26b is equal to or less than the upper limit of the above-mentioned range, the fluidity of the isotropic conductive adhesive layer 26 (the conformability to the shape of the through hole in the insulating film) can be ensured, and it is possible to use The conductive adhesive sufficiently fills the inside of the through hole of the insulating film.

The ratio 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 in 100% by volume of the isotropic conductive adhesive layer 26, and more preferably Preferably it is 60 volume% or more and 70 volume% or less. The electroconductivity of the isotropic conductive adhesive bond layer 26 becomes favorable as the ratio of the electroconductive particle 26b is more than the lower limit of the said range. If the ratio of the conductive particles 26b is equal to or less than the upper limit of the above-mentioned range, the adhesiveness and fluidity of the isotropic conductive adhesive layer 26 (the conformability to the shape of the through-hole of the insulating film) will be favorable. . Moreover, the flexibility of the electromagnetic wave shielding film 1 becomes favorable.

The storage elastic modulus at 180° C. of the isotropic conductive adhesive layer 26 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. The reason why the above-mentioned range is preferable is the same as that of the anisotropic conductive adhesive layer 24 .

The surface resistance of the isotropic conductive adhesive layer 26 is preferably 0.05Ω or more and 2.0Ω or less, and more preferably 0.1Ω or more and 1.0Ω or less. If the surface resistance of the isotropic conductive adhesive layer 26 is equal to or more than the lower limit value of the above-mentioned range, the content of the conductive particles 26b can be controlled to be low, the viscosity of the conductive adhesive is not too high, and the coating Cloth properties became better. In addition, the fluidity of the isotropic conductive adhesive layer 26 (the compliance with 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-mentioned range, the entire surface of the isotropic conductive adhesive layer 26 has uniform conductivity.

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 equal to or more than the lower limit value of the above-mentioned range, the conductivity of the isotropic conductive adhesive layer 26 becomes good, and the function of the electromagnetic wave shielding layer can be sufficiently exerted. In addition, the fluidity of the isotropic conductive adhesive layer 26 (the compliance with the shape of the through hole in the insulating film) can be ensured, the inside of the through hole in the insulating film can be sufficiently filled with the conductive adhesive, and the In terms of folding endurance, the isotropic conductive adhesive layer 26 does not break even when it is repeatedly folded.

If the thickness of the isotropic conductive adhesive layer 26 is equal to or less than the upper limit of the above-mentioned range, the electromagnetic wave shielding film 1 can be thinned. Moreover, the flexibility of the electromagnetic wave shielding film 1 becomes favorable.

(carrier film)

The carrier film 30 is a support that reinforces and protects the insulating resin layer 10 and the conductive layer 20 , making the electromagnetic wave shielding film 1 good in handleability. In particular, when a thin film, specifically a film having a thickness of 3 μm or more and 10 μm or less is used as the insulating resin layer 10 , the insulating resin layer 10 can be prevented from breaking by having the carrier film 30 .

After the electromagnetic wave shielding film 1 is attached to a printed wiring board or the like, the carrier film 30 is peeled off from the insulating resin layer 10 .

The carrier film 30 used in this embodiment has a carrier film main body 32 and an adhesive layer 34 provided on the surface of the carrier film main body 32 on the insulating resin layer 10 side.

Examples of the resin material for the carrier film body 32 include polyethylene terephthalate (hereinafter, also referred to as "PET" in some cases), polyethylene naphthalate, and polyethylene isophthalate. Alcohol ester, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride , synthetic rubber, liquid crystal polymer, etc. As the resin material, PET is preferable from the viewpoints of heat resistance (dimensional stability) and price when the electromagnetic wave shielding film 1 is produced.

The carrier film body 32 may contain either or both of colorants (pigments, dyes, etc.) and fillers.

As either or both of the colorant and the filler, it is preferable to use a colorant different from that of the insulating resin layer 10 because it can be clearly distinguished from the insulating resin layer 10 and the peeling residue of the carrier film 30 is easily found after hot pressing. , more preferably white pigments, fillers or combinations of white pigments with other pigments or fillers.

The storage modulus at 180° C. of the carrier film main body 32 is preferably 8×10 ⁷ Pa or more and 5×10 ⁹ Pa or less, and more preferably 1×10 ⁸ Pa or more and 8×10 ⁸ Pa or less. If the storage modulus of the carrier film main body 32 at 180° C. is equal to or higher than the lower limit of the above range, the carrier film 30 has suitable hardness and can reduce pressure loss on the carrier film 30 during hot pressing. The flexibility of the carrier film 30 becomes favorable as the storage elastic modulus in 180 degreeC of the carrier film main body 32 is below the upper limit of the said range.

The thickness of the carrier 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. The handleability of the electromagnetic wave shielding film 1 becomes favorable as the thickness of the carrier film main body 32 is more than the lower limit of the said range. When the thickness of the carrier film main body 32 is equal to or less than the upper limit of the above-mentioned range, the conductive adhesive layer (anisotropic conductive adhesive layer 24 or isotropic adhesive layer 24 or isotropic adhesive layer 24 of the electromagnetic wave shielding film 1) is thermally pressed on the surface of the insulating film. In the case of the same conductive adhesive layer 26), heat is easily conducted to the conductive adhesive layer.

The adhesive layer 34 is formed by applying, for example, an adhesive composition containing an adhesive on the surface of the carrier film body 32 . By providing the carrier film 30 with the adhesive layer 34, the carrier film 30 can be suppressed when the release film 40 is peeled from the conductive adhesive layer or when the electromagnetic wave shielding film 1 is attached to a printed wiring board or the like by thermocompression. peeled from the insulating resin layer 10 . Therefore, the carrier film 30 can fully function as a protective film.

As the adhesive, a substance that imparts appropriate adhesiveness to the adhesive layer 34 is preferable. The appropriate adhesiveness means that the carrier film 30 is not easily peeled from the insulating resin layer 10 before hot pressing, and the carrier film 30 can be removed from the insulating resin layer 10 after hot pressing. The degree to which the insulating resin layer 10 is peeled off.

As an adhesive, an acrylic adhesive, a urethane adhesive, a silicone adhesive, a rubber adhesive etc. are mentioned.

The glass transition temperature of the binder is preferably -100°C or higher and 60°C or lower, and more preferably -60°C or higher and 40°C or lower.

The thickness of the carrier 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 carrier film 30 is equal to or more than the lower limit value of the above-mentioned range, the handleability of the electromagnetic wave shielding film 1 becomes favorable. When the thickness of the carrier film 30 is below the upper limit of the above-mentioned range, heat is easily transferred to the conductive adhesive layer when the conductive adhesive layer of the electromagnetic wave shielding film 1 is thermally pressed on the surface of the insulating film.

(release film)

The release film 40 protects the conductive adhesive layer (the anisotropic conductive adhesive layer 24 or the isotropic conductive adhesive layer 26 ), and improves the handleability of the electromagnetic wave shielding film 1 . Before attaching the electromagnetic wave shielding film 1 to a printed wiring board or the like, the release film 40 is removed from the conductive adhesive layer (anisotropic conductive adhesive layer 24 or isotropic conductive adhesive layer 26 ). stripped.

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

As a resin material of the release film main body 42, the thing similar to the resin material of the carrier film main body 32 is mentioned.

The release film body 42 may contain colorants, fillers, and the like.

The thickness of the release film main 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 surface of the release film main body 42 is processed with a release agent, and the release agent layer 44 is formed. By providing the release film 40 with the release agent layer 44, when the release film 40 is peeled off from the conductive adhesive layer, the release film 40 is easily peeled off, and the conductive adhesive layer is less likely to be broken.

As a mold release agent, a well-known mold 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. If the thickness of the release agent layer 44 is within the above-mentioned range, the release film 40 will be more easily peeled off.

(Thickness of electromagnetic wave shielding film)

The thickness of the electromagnetic wave shielding film 1 (excluding the carrier film 30 and the release film 40 ) is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 30 μm or less. When the thickness of the electromagnetic wave shielding film 1 excluding the carrier film 30 and the release film 40 is equal to or more than the lower limit value of the above-mentioned range, the carrier film 30 will not be easily broken when peeled off. If the thickness of the electromagnetic wave shielding film 1 excluding the carrier film 30 and the release film 40 is equal to or less than the upper limit of the above-mentioned range, the printed wiring board with the electromagnetic wave shielding film can be thinned.

<Manufacturing method of electromagnetic wave shielding film>

A second aspect of the present invention is a method for producing an electromagnetic wave shielding film, comprising the steps of: forming a mixed resin of aromatic polyetherketone and polyetherimide into a film shape to form an insulating resin layer; and A step of forming a conductive layer on one surface of the insulating resin layer.

Specifically, as a method of manufacturing the electromagnetic wave shielding film of 1st Embodiment, the following method (A1) and method (A2) are mentioned. As a method of manufacturing the electromagnetic wave shielding film of 2nd Embodiment, the following method (B1) and method (B2) are mentioned. As a method of manufacturing the electromagnetic wave shielding film of 3rd Embodiment, the following method (C1) and method (C2) are mentioned.

The method (A1) is a method having the following steps (A1-1) to (A1-4).

Step (A1-1): A step of forming a mixed resin of aromatic polyetherketone and polyetherimide into a film shape, and laminating the formed insulating resin layer 10 on the carrier film 30 .

Step (A1-2): A step of forming the metal thin film layer 22 on the surface of the insulating resin layer 10 on the opposite side to the carrier film 30 .

Step (A1-3): A step of forming the anisotropic conductive adhesive layer 24 on the surface of the metal thin film layer 22 on the opposite side to the insulating resin layer 10 .

Step (A1-4): A step of laminating the release film 40 on the surface of the anisotropic conductive adhesive layer 24 on the opposite side to the metal thin film layer 22 .

Next, each step of the method (A1) will be described in detail.

In step (A1-1), the mixed resin of aromatic polyetherketone and polyetherimide is formed into a film shape. As the molding method, a melt extrusion molding method, a calender molding method, a casting method, etc. can be mentioned, and the melt extrusion molding method is preferable from the viewpoint of simplifying the equipment.

In the melt extrusion molding method, the above-mentioned resin is melt-kneaded using a melt-extrusion molding machine, and is continuously extruded into a belt shape from a T-die provided at the front end of the melt-extrusion molding machine, thereby molding the above-mentioned resin into a film shape . The preferable temperature at the time of melt-kneading is as described above.

The water content of the above-mentioned resin supplied to the melt extrusion molding machine is preferably 0 ppm or more and 5000 ppm or less, and more preferably 0 ppm or more and 2000 ppm or less. If the moisture content of the resin is equal to or less than the upper limit value, the resin can be prevented from foaming.

In order to prevent the above-mentioned resin oxidative degradation and oxygen crosslinking during melt-kneading, it is preferable to make the feed port of the melt extrusion molding machine an inert gas atmosphere. As the inert gas, for example, helium gas, neon gas, argon gas, krypton gas, nitrogen gas, carbon dioxide gas and the like can be used.

The molten film extruded from the T die is preferably cooled against a metal roll. The temperature of the metal roll is preferably lower than the melting point of the above-mentioned resin, and more preferably lower than the crystallization temperature. If the temperature of the metal roll is lower than the melting point of the above-mentioned resin, the film can be prevented from breaking.

The film-like insulating resin layer 10 obtained as described above is laminated on the surface of the carrier film 30 on which the adhesive layer 34 is provided.

When the conductive layer 20 has a blackened layer, the blackened layer may be formed on the insulating resin layer 10 obtained as described above by vapor deposition, plating, or the like.

Examples of the method of forming the metal thin film layer in the step (A1-2) include a method of forming a vapor-deposited film by physical vapor deposition, CVD (chemical vapor deposition), a method of forming a plated film by plating, and a method of affixing a metal foil. method etc. The method of forming a vapor-deposited film by physical vapor deposition, CVD, or the method of forming a plated film by plating is preferable because a metal thin film layer having excellent electrical conductivity in the plane direction can be formed. Since the thickness of the metal thin film layer can be reduced, a metal thin film layer having excellent electrical conductivity in the plane direction can be formed even if the thickness is thin, and the metal thin film layer can be easily formed by a dry process, physical vapor deposition is more preferable. 2. The method of forming the vapor-deposited film by CVD, and the method of forming the vapor-deposited film by physical vapor deposition is more preferable.

In the step (A1-3), the conductive adhesive paint is applied on the surface of the metal thin film layer 22 on the opposite side to the insulating resin layer 10 . The conductive adhesive paint contains the thermosetting adhesive 24a, the conductive particles 24b, and a solvent. The anisotropic conductive adhesive layer 24 is formed by volatilizing the solvent from the applied conductive adhesive paint.

Examples of the solvent contained in the conductive adhesive coating material include esters (butyl acetate, ethyl acetate, methyl acetate, isopropyl acetate, ethylene glycol monoacetate, etc.), ketones (methyl acetate, etc.) ethyl ketone, methyl isobutyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, etc.), alcohols (methanol, ethanol, isopropanol, butanol, propylene glycol monomethyl ether, propylene glycol, etc.) and the like.

As a coating method of the conductive adhesive, for example, a method using the following various coaters can be applied: a die coater, a gravure coater, a roll coater, a curtain flow coater, and a spin coater. Machine, Bar Coater, Reverse Roll Coater, Match Coater, Jet Coater, Bar Coater, Air Knife Coater, Knife Coater, Blade Coater machine, casting coater, screen coater and other coating machines.

In step (A1-4), the release film 40 is laminated on the anisotropic conductive adhesive layer 24 and the metal so that the release agent layer 44 is in contact with the anisotropic conductive adhesive layer 24 The surface on the opposite side of the thin film layer 22 .

After laminating the release film 40 on the anisotropic conductive adhesive layer 24 , the layers containing the carrier film 30 , the insulating resin layer 10 , the metal thin film layer 22 , the anisotropic conductive adhesive layer 24 and the release film The laminated body of 40 is subjected to pressure treatment to improve the adhesion between the layers.

The pressure at the time of pressurization is preferably 0.1 kPa or more and 100 kPa 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.

Heating may be performed simultaneously with the pressure treatment. The heating temperature at this time is preferably 50°C or higher and 100°C or lower.

The method (A2) is a method having the following steps (A2-1) to (A2-4).

Step (A2-1): A step of forming a mixed resin of aromatic polyetherketone and polyetherimide into a film shape, and laminating the formed insulating resin layer 10 on the carrier film 30 .

Step (A2-2): A step of forming the laminated body (I) by forming the metal thin film layer 22 on the surface of the insulating resin layer 10 opposite to the carrier film 30 .

Process (A2-3): The process of forming the anisotropic conductive adhesive bond layer 24 on the release film 40, and forming the laminated body (II).

Step (A2-4): Laminating the laminate (I) and the laminate (II) so that the metal thin film layer 22 of the laminate (I) and the anisotropic conductive adhesive layer 24 of the laminate (II) are in contact with each other ) process.

The step (A2-1) and the step (A2-2) are the same as the step (A1-1) and the step (A1-2) in the above-mentioned method (A1).

In the step (A2-3), the conductive adhesive paint is applied on the surface of the release film 40 on which the release agent layer 44 is provided. The anisotropic conductive adhesive layer 24 is formed by volatilizing the solvent from the applied conductive adhesive paint. The conductive adhesive coating material and the coating method are the same as the step (A1-3) in the above-mentioned method (A).

In the step (A2-4), when the laminated body (I) and the laminated body (II) are bonded together, a heat treatment may be performed to improve the adhesion between the laminated body (I) and the laminated body (II). The pressurizing conditions are the same as the pressurizing treatment in the step (A1-4). In addition, in the step (A2-4), heating may be performed in the same manner as in the step (A1-4).

In the method (B1), the isotropic conductive adhesive layer 26 is formed by changing the conductive adhesive coating material to a coating material containing the thermosetting adhesive 26a, the conductive particles 26b and the solvent , same as method (A1).

In the method (B2), the isotropic conductive adhesive layer 26 is formed by changing the conductive adhesive coating material to a coating material containing the thermosetting adhesive 26a, the conductive particles 26b and the solvent , same as method (A2).

The method (C1) is a method having the following steps (C1-1) to (C1-3).

Step (C1-1): A step of forming a mixed resin of aromatic polyetherketone and polyetherimide into a film shape, and laminating the formed insulating resin layer 10 on the carrier film 30 .

Step (C1-2): A step of forming the isotropic conductive adhesive layer 26 on the surface of the insulating resin layer 10 opposite to the carrier film 30 .

Step (C1-3): A step of laminating the release film 40 on the surface of the isotropic conductive adhesive layer 26 on the opposite side to the insulating resin layer 10 .

In the method (C1), the formation of the metal thin film layer is omitted, and the isotropic conductive adhesive layer 26 is directly formed on the insulating resin layer 10 using an isotropic conductive adhesive as the conductive adhesive. Other than that, it is the same as method (A1).

The method (C2) is a method having the following steps (C2-1) to (C2-3).

Step (C2-1): The mixed resin of aromatic polyetherketone and polyetherimide is formed into a film shape, and the formed insulating resin layer 10 is laminated on the carrier film 30 to form the laminated body (I). process.

Step (C2-2): The step of forming the isotropic conductive adhesive layer 26 on the release film 40 to form the laminate (II).

Step (C2-3): Laminating the laminate (I) and the laminate (II) so that the insulating resin layer 10 of the laminate (I) and the isotropic conductive adhesive layer 26 of the laminate (II) are in contact with each other ) process.

In the method (C2), the formation of the metal thin film layer is omitted, the isotropic conductive adhesive is used as the conductive adhesive, and the isotropic conductive adhesive layer 26 is pasted on the insulating resin layer 10, except Otherwise, it is the same as method (A2).

(Effect)

According to the electromagnetic wave shielding film 1 of this aspect in which the insulating resin layer 10 contains the mixed resin of aromatic polyetherketone and polyetherimide, the adhesive force of the insulating resin layer 10 to the conductive layer 20 containing metal can be improved. Therefore, it is possible to prevent interlayer peeling between the insulating resin layer 10 and the conductive layer 20 during the processing of the electromagnetic wave shielding film 1 . In particular, when the conductive layer 20 has the metal thin film layer 22, this effect is exhibited, and the insulating resin layer 10 containing the mixed resin of aromatic polyether ketone and polyetherimide can be strongly bonded to the metal thin film layer 22 with high adhesive force. bonding.

(Other Embodiments)

The electromagnetic wave shielding film of this embodiment is not limited to the above-mentioned embodiment.

For example, when the surface adhesive force of the anisotropic conductive adhesive layer 24 or the isotropic conductive adhesive layer 26 is small, the release film 40 may be omitted.

When the insulating resin layer 10 has sufficient flexibility and strength, the carrier film 30 may be omitted.

When the carrier film main body 32 is a self-adhesive film, the carrier film 30 may omit the adhesive layer 34 .

When the release film main body 42 alone has sufficient releasability, the release film 40 can omit the release agent layer 44 .

<Printed Wiring Board with Electromagnetic Wave Shielding Film>

A third aspect of the present invention is a printed wiring board with an electromagnetic wave shielding film, comprising: a printed wiring board provided with a printed circuit on at least one side of a substrate; and an insulating film provided with the above printed wiring board The surface of one side of a circuit is adjacent; and the electromagnetic wave shielding film of the above-mentioned form is provided so that the above-mentioned adhesive bond layer may be adjacent to the above-mentioned insulating film.

FIG. 4 is a cross-sectional view showing one embodiment of the electromagnetic wave shielding film-equipped printed wiring board of the present embodiment.

The electromagnetic wave shielding film-attached printed wiring board 2 includes a flexible printed wiring board 50 , an insulating film 60 , and the electromagnetic wave shielding film 1 of the first embodiment.

The flexible printed wiring board 50 is provided with the 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 the surface of the insulating film 60 and cured. In addition, the anisotropic conductive adhesive layer 24 is electrically connected to the printed circuit 54 via a through hole (not shown) formed in the insulating film 60 .

In the printed wiring board 2 with the electromagnetic wave shielding film, the mold release film is peeled off from the anisotropic conductive adhesive layer 24 .

When the carrier film 30 is unnecessary in the printed wiring board 2 with the electromagnetic wave shielding film, the carrier 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.) other than the portion having the through hole, the electromagnetic wave shields are arranged to face each other with the insulating film 60 and the anisotropic conductive adhesive layer 24 interposed therebetween. Metal thin film layer 22 of film 1 .

The 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 less than 30 μm, the resistance of the signal circuit decreases. Therefore, in order to have a characteristic resistance such as 100Ω, the line width of the signal circuit must be reduced, and the instability of the line width becomes the instability of the characteristic resistance, which is caused by resistance mismatch. Reflected resonance noise is easily mixed into electrical signals. If the spacing distance is larger than 200 μm, the printed wiring board 2 with the electromagnetic wave shielding film becomes thick and the flexibility is insufficient.

(Flexible Printed Circuit Board)

The flexible printed wiring board 50 is a printed circuit 54 formed by processing the copper foil of the copper-clad laminate into a desired pattern by a known etching method.

Examples of the copper-clad laminate include those in which copper foil is pasted on one side or both sides of the base film 52 through an adhesive layer (not shown); casting is used to form the base film 52 on the surface of the copper foil. of resin solution, etc.

As a material of an adhesive bond layer, an epoxy resin, polyester, polyimide, polyamideimide, polyamide, phenol resin, polyurethane resin, acrylic resin, melamine resin, etc. are mentioned.

The thickness of the adhesive bond layer is preferably 0.5 μm or more and 30 μm or less.

[Basement film]

The base film 52 is preferably a film having heat resistance, more preferably a polyimide film, a polyetherimide film, a polyphenylene sulfide film, or a liquid crystal polymer film, and still more preferably a polyimide film.

From the viewpoint of electrical insulating properties, the surface resistance of the base film 52 is preferably 1×10 ⁶ Ω or more. From a practical point of view, the surface resistance of the base film 52 is preferably 1×10 ¹⁹ Ω or less.

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 50 μm or less, and more preferably 10 μm or more and 25 μm or less, from the viewpoint of flexibility.

[printed circuit]

As a copper foil which comprises the printed circuit 54, a rolled copper foil, an electrolytic copper foil, etc. are mentioned, From a viewpoint of flexibility, a rolled copper foil is preferable. The printed circuit 54 can be used as, for example, a signal circuit, a ground circuit, a ground layer, or the like.

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.

Ends (terminals) in the longitudinal direction of the printed circuit 54 are exposed without being covered by the insulating film 60 or the electromagnetic wave shielding film 1 , and are connected to solder, connection tabs, mounting members, and the like.

(insulating film)

The insulating film 60 (cover film) is a film in which an adhesive layer (not shown) is formed on one side of an insulating film main body (not shown) by applying an adhesive, sticking an adhesive sheet, or the like.

From the viewpoint of electrical insulating properties, the surface resistance of the insulating film body is preferably 1×10 ⁶ Ω or more. From a practical standpoint, the surface resistance of the insulating film body is preferably 1×10 ¹⁹ Ω or less.

As the insulating film main body, a film having heat resistance is preferable, a polyimide film, a polyetherimide film, a polyphenylene sulfide film, and a liquid crystal polymer film are more preferable, and a polyimide film is still more 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 in view of flexibility.

Examples of the material of the adhesive bond layer include epoxy resin, polyester, polyimide, polyamideimide, polyamide, phenolic resin, polyurethane resin, acrylic resin, melamine resin, polyphenylene Ethylene, polyolefin, etc. The epoxy resin may contain a rubber component (carboxy-modified nitrile rubber, etc.) for imparting flexibility.

The thickness of the adhesive bond 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 formed in the insulating film 60 is not particularly limited. As a shape of the opening part of a through-hole, a circle, an ellipse, a quadrangle, etc. are mentioned, for example.

<Manufacturing method of printed wiring board with electromagnetic wave shielding film>

The method for producing a printed wiring board with an electromagnetic wave shielding film according to a fourth aspect of the present invention includes a step of connecting a printed wiring board with a printed circuit on at least one side of a substrate and the electromagnetic wave shielding film of the above aspect via an insulating film Crimp bonding is performed, and at the time of crimping, the insulating film is brought into close contact with the surface of the printed wiring board on the side where the printed circuit is provided, and at the same time, it is also closely adhered to the conductive adhesive layer of the electromagnetic wave shielding film. superior.

The electromagnetic wave shielding film-equipped printed wiring board 2 of the above-described embodiment can be produced, for example, by a method including the following steps (a) to (d) (see FIG. 5 ).

Step (a): Disposing an insulating film 60 on the surface of the flexible printed wiring board 50 on the side where the printed circuit 54 is provided, the insulating film 60 having through holes 62 formed at positions corresponding to the printed circuit 54, and obtaining a tape Process of the printed wiring board 3 with the insulating film.

Step (b): After the step (a), the printed wiring board 3 with the insulating film and the surface of the insulating film 40 are separated so that the anisotropic conductive adhesive layer 24 is in contact with the surface of the insulating film 60 . A process of overlapping the electromagnetic wave shielding films 1 and crimping them.

Step (c): After the step (b), when the carrier film 30 is unnecessary, the step of peeling off the carrier film 30 .

Step (d): If necessary, between the step (a) and the step (b) or after the step (c), a step of actually curing the anisotropic conductive adhesive layer 24 .

Next, each step will be described in detail with reference to FIG. 5 .

(Process (a))

The step (a) is a step of laminating the insulating film 60 on the flexible printed wiring board 50 to obtain the printed wiring board 3 with the insulating film.

Specifically, first, the insulating film 60 having the through holes 62 formed at the positions corresponding to the printed circuit 54 is superimposed on the flexible printed wiring board 50 . Next, an adhesive layer (not shown) of the insulating film 60 is adhered to the surface of the flexible printed wiring board 50 and the adhesive layer is cured, whereby the printed wiring board 3 with the insulating film is obtained. 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 (d).

The bonding and curing of the adhesive layer are performed by hot pressing using, for example, a press (not shown).

(Process (b))

The step (b) is a step of crimping the electromagnetic wave shielding film 1 on the printed wiring board 3 with an insulating film.

Specifically, the electromagnetic wave shielding film 1 after peeling the mold release film 40 is stacked on the printed wiring board 3 with an insulating film, and is crimped by thermocompression or the like. As a result, the anisotropic conductive adhesive layer 24 is adhered to the surface of the insulating film 60 , and the anisotropic conductive adhesive layer 24 is pressed into the through holes 62 to fill the interior of the through holes 62 . Circuit 54 is electrically connected. Thereby, the printed wiring board 2 with the electromagnetic wave shielding film was obtained.

The adhesion and curing of the anisotropic conductive adhesive layer 24 are performed by hot pressing using, for example, a press (not shown).

The hot pressing time is preferably 20 seconds or more and 60 minutes or less, and more preferably 30 seconds or more and 30 minutes or less. The anisotropic conductive adhesive layer 24 can be easily adhered to the surface of the insulating film 60 as long as the hot pressing time is equal to or more than the lower limit of the above-mentioned range. If the hot pressing time is equal to or less than the upper limit of the above range, the production time of the electromagnetic wave shielding film-attached printed wiring board 2 can be shortened.

The hot pressing temperature (temperature of the hot plate of the press) is preferably 140°C or higher and 190°C or lower, and more preferably 150°C or higher and 175°C or lower. If the temperature of the hot pressing is equal to or higher than the lower limit value of the above range, the anisotropic conductive adhesive layer 24 can be easily adhered to the surface of the insulating film 60 . In addition, the hot pressing time can be shortened. If the hot pressing temperature is equal to or less than the upper limit value of the above-mentioned range, deterioration of the electromagnetic wave shielding film 1 , the flexible printed wiring board 50 , and the like can be easily suppressed.

The pressure of the hot pressing is preferably 0.5 MPa or more and 20 MPa or less, and more preferably 1 MPa or more and 16 MPa or less. The anisotropic conductive adhesive layer 24 can be adhered to the surface of the insulating film 60 as long as the pressure of the hot pressing is equal to or more than the lower limit value of the above-mentioned range. In addition, the hot pressing time can be shortened. If the pressure of the hot pressing is equal to or less than the upper limit of the above-mentioned range, breakage and the like of the electromagnetic wave shielding film 1 , the flexible printed wiring board 50 , and the like can be suppressed.

(Process (c))

The step (c) is a step of peeling off the carrier film 30 .

Specifically, when the carrier film is not required, the carrier film 30 is peeled off from the insulating resin layer 10 .

(Process (d))

Step (d) is a step of actually curing the anisotropic conductive adhesive layer 24 .

When the hot pressing time in the step (b) is as short as 20 seconds or more and 10 minutes or less, it is preferable to perform each direction between the step (b) and the step (c), or after the step (c). The main curing of the anisotropic conductive adhesive layer 24 is completed.

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 preferably 15 minutes or more and 120 minutes or less, and more preferably 30 minutes or more and 60 minutes or less. When the heating time is equal to or more than the lower limit of the above range, the anisotropic conductive adhesive layer 24 can be sufficiently cured. If the heating time is equal to or less than the upper limit value of the above range, the production time of the electromagnetic wave shielding film-attached printed wiring board 2 can be shortened.

The heating temperature (atmosphere temperature in the oven) is preferably 120°C or higher and 180°C or lower, and more preferably 120°C or higher and 150°C or lower. If the heating temperature is equal to or higher than the lower limit value of the above-mentioned range, the heating time can be shortened. If the heating temperature is equal to or less than the upper limit of the above-mentioned range, deterioration of the electromagnetic wave shielding film 1 , the flexible printed wiring board 50 , and the like can be suppressed.

(Effect)

Since the electromagnetic wave shielding film 1 described above is used in the printed wiring board with the electromagnetic wave shielding film of the present embodiment, the adhesive force between the insulating resin layer 10 and the conductive layer 20 made of metal is sufficiently high. Therefore, interlayer peeling between the insulating resin layer 10 and the conductive layer 20 can be prevented.

(Other Embodiments)

The printed wiring board with the electromagnetic wave shielding film of this embodiment is not limited to the above-mentioned embodiment.

For example, the flexible printed wiring board 50 may have a ground layer on the back side. In addition, the flexible printed wiring board 50 may have the printed circuit 54 on both sides, and the insulating film 60 and the electromagnetic wave shielding film 1 may be pasted on both sides.

In place of the flexible printed wiring board 50, a rigid printed circuit board having no flexibility may be used.

Instead of the electromagnetic wave shielding film 1 of the first embodiment, the electromagnetic wave shielding film 1 of the second embodiment or the electromagnetic wave shielding film 1 of the third embodiment may be used.

Example

[Example 1]

(Preparation of Hybrid Resin and Film Formation)

First, PEEK [Product name from Solvay Specialty Polymers: KetaSpire Polyetheretherketone Product name: KT-851NL SP] and PEI [Product name from SABIC: ULTEM, 9011-1000-NB, glass transition temperature: 210°C] The composition mass ratio was put into a drum mixer so that PEEK: 90 mass % and PEI: 10 mass %, and the drum mixer was stirred and mixed at 23° C. for 1 hour to prepare a stirred mixture.

The stirred mixture obtained by stirring and mixing PEEK and PEI is supplied to a twin-screw extruder with a vacuum pump, melt-kneaded under reduced pressure, and extruded into a rod shape from a die at the front end of the twin-screw extruder. , water-cooled and then cut to prepare a pellet-shaped molding material as an intermediate. The stirred mixture was melt-kneaded under the conditions of a barrel temperature of 360 to 380°C, a die temperature of 380°C, and a temperature of 380°C of a connecting pipe connecting the twin-screw extruder and the die.

The molding material was then dried in a dehumidifying dryer heated to 150°C for 12 hours, and the dried molding material was placed in a single-screw extruder with a T-die with a width of 900 mm and a screw diameter of 40 mm, and melted. kneading. The melt-kneaded molding material was continuously extruded from the T-die of the single-screw extruder to extrude a film for an insulating resin layer (thickness 5 μm) in a strip shape.

The vitrification of the film for insulating resin layers was measured using a differential scanning calorimeter [manufactured by SII Nano Technology Co., Ltd.: product name high-sensitivity differential scanning calorimeter X-DSC7000] based on JIS K7121 at a temperature increase rate of 10°C/min. transition temperature. The same applies to the measurement of the glass transition temperature in the following Examples and Comparative Examples. The glass transition temperature of the film for insulating resin layers was 148°C.

The tensile modulus at 160° C. of the film for an insulating resin layer was measured with respect to the extrusion direction and the width direction (direction perpendicular to the extrusion direction) of the film as described below. A test piece was cut out according to JIS K7160 type 3, and the test piece was mounted on a jig of a tensile testing machine with a thermostatic bath preheated to 160°C. The door of the thermostatic bath was closed, and the temperature of the thermostatic bath reached 160°C. After standing at ±2°C for 3 minutes, it was measured at a tensile speed of 50 mm/min based on JIS K7127. The results of the measurement are shown below.

Tensile modulus of film in extrusion direction: 1100 N/mm ²

Tensile modulus in the width direction of the film: 1046N/mm ²

(Manufacture of electromagnetic wave shielding film)

A carrier film provided with an adhesive layer containing an acrylic adhesive on one side of a PET film (carrier film main body) was prepared. The insulating resin layer containing the film for insulating resin layers described above is bonded to the surface of the adhesive layer of the carrier film.

Next, copper was physically vapor-deposited on the surface of the insulating resin layer opposite to the carrier film by electron beam vapor deposition to form a metal thin film layer (copper vapor-deposited film, thickness 0.07 μm, surface resistance 0.3Ω).

100 parts by mass of a thermosetting adhesive containing an epoxy resin (manufactured by DIC Corporation, EXA-4816) and 20 parts by mass of a curing agent (manufactured by Ajinomoto Fine-Techno Co., Inc., PN-23) were mixed to obtain a latent curable epoxy resin resin composition.

The above-mentioned latent curable epoxy resin composition and 40 parts by mass of conductive particles (average particle diameter: 7.5 μm) containing copper particles were dissolved or dispersed in 200 parts by mass of a solvent containing methyl ethyl ketone to obtain conductive adhesion agent paint.

Next, using a die coater, the conductive adhesive paint is applied on the surface of the metal thin film layer opposite to the insulating resin layer, and the solvent is volatilized to B-stage, thereby forming anisotropy. Conductive adhesive layer (thickness 7 μm, copper particle 4.5 volume %).

A release film (manufactured by Lintec, T157) in which a release agent layer (thickness 0.1 μm) containing a non-silicone-based release agent was provided on one side of a PET film (thickness 50 μm) was prepared.

The above-mentioned release film was attached to the surface opposite to the metal thin film layer of the above-mentioned anisotropic conductive adhesive layer so that the above-mentioned release agent layer was brought into contact with the above-mentioned anisotropic conductive adhesive layer, and the implementation was carried out. The electromagnetic wave shielding film of Example 1.

[Example 2]

PEEK [manufactured by Daicel Evonik, product name: VESTAKEEP, product name: 3300G] and PEI [manufactured by SABIC, product name: ULTEM: 1010-1000-NB, glass transition temperature: 211°C], and the composition mass ratio is PEEK: 70 mass % and PEI: 30 mass % were put into a drum mixer, and thereafter, a stirring mixture was prepared in the same manner as in Example 1, and an electromagnetic wave shielding film was produced. The glass transition temperature of the film for insulating resin layers was 160°C. The tensile modulus in 160 degreeC of the film for insulating resin layers is as follows.

Tensile modulus of film in extrusion direction: 2239N/mm ²

Tensile modulus in the width direction of the film: 1661 N/mm ²

[Example 3]

PEEK [Solvay Specialty Polymers company product name: KetaSpire polyether ether ketone product name: KT-820NT] and the PEI used in Example 2 were put into the rotary A drum mixer was used, and thereafter, in the same manner as in Example 1, a stirring mixture was prepared, and an electromagnetic wave shielding film was produced. The glass transition temperature of the film for insulating resin layers was 174°C. The tensile modulus in 160 degreeC of the film for insulating resin layers is as follows.

Tensile modulus of film in extrusion direction: 2331N/mm ²

Tensile modulus in the width direction of the film: 2013N/mm ²

[Example 4]

PEEK (product name: Victrex PEEK381G, manufactured by Victrex) and PEI used in Example 2 were put into a drum mixer so that the composition mass ratios were PEEK: 20 mass % and PEI: 80 mass %. The same method was used to prepare the stirring mixture and manufacture the electromagnetic wave shielding film. The glass transition temperature of the film for insulating resin layers was 198°C. The tensile modulus in 160 degreeC of the film for insulating resin layers is as follows.

Tensile modulus of film in extrusion direction: 2720N/mm ²

Tensile modulus in the width direction of the film: 2568 N/mm ²

[Example 5]

The PEEK and PEI used in Example 1 were put into a tumbler mixer so that the composition mass ratios were PEEK: 10 mass % and PEI: 90 mass %, and then a stirring mixture was prepared and electromagnetic waves were produced in the same manner as in Example 1. shielding film. The glass transition temperature of the film for insulating resin layers was 202°C. The tensile modulus in 160 degreeC of the film for insulating resin layers is as follows.

Tensile modulus of film in extrusion direction: 2830N/mm ²

Tensile modulus in the width direction of the film: 2660 N/mm ²

[Example 6]

The electromagnetic wave shielding film of Example 6 was obtained in the same manner as in Example 2, except that PEKK (product name: KEPSTAN 8002, manufactured by ARKEMA) was used instead of PEEK. The glass transition temperature of the film for insulating resin layers was 204°C. The tensile modulus in 160 degreeC of the film for insulating resin layers is as follows.

Tensile modulus of film in extrusion direction: 2530N/mm ²

Tensile modulus in the width direction of the film: 2439 N/mm ²

(Comparative Example 1)

As a coating material for forming the insulating resin layer, 100 parts by mass of a bisphenol A epoxy resin (manufactured by DIC, epichlone 840-S), 20 parts by mass of a curing agent (manufactured by Mitsubishi Chemical Corporation, JER Cure 113), 2- 2 parts by mass of ethyl-4-methylimidazole and 2 parts by mass of carbon black were dissolved in 200 parts by mass of methyl ethyl ketone to prepare a coating material.

The above-mentioned coating material for forming the insulating resin layer was applied on the surface of the adhesive layer of the same carrier film as the carrier film used in Example 1, heated at 60° C. for 2 minutes, dried, and semi-cured to form a thickness of 5μm insulating resin layer. In this insulating resin layer, 1 pinhole/m ² or more and 3 pinholes/m ² or less were observed.

A region without pinholes is selected, and copper is physically evaporated on the surface of the insulating resin layer in the selected region by electron beam evaporation to form a metal thin film layer (copper evaporation film, thickness 0.07 μm, surface resistance 0.3Ω) .

In the same manner as in Example 1, an anisotropic conductive adhesive layer was formed on the surface opposite to the insulating resin layer of the metal thin film layer, and a release film was pasted on the anisotropic conductive adhesive layer to obtain The electromagnetic wave shielding film of Comparative Example 1.

[Evaluation]

The adhesiveness of the insulating resin layer and the conductive layer of the electromagnetic wave shielding film of each example was evaluated by the following method.

The electromagnetic wave shielding film after peeling the release film was superimposed on a polyimide film with a thickness of 25 μm, and heated at a hot plate temperature: 180° C. and a load: 2 MPa using a hot pressing apparatus (manufactured by Orihara, Ltd., G-12). Press for 120 seconds. Next, the carrier film is peeled off. Thereby, the anisotropic conductive adhesive layer was temporarily adhered to the surface of the insulating film, and the polyimide with the electromagnetic wave shielding film was obtained.

The anisotropic conductive adhesive layer was fully cured by heating the above-mentioned polyimide film with an electromagnetic wave shielding film at a temperature of 160° C. for 1 hour using a high-temperature bath (manufactured by Kusumoto Chemical Co., Ltd., HT210).

Next, a polyimide reinforcing plate having a thickness of 25 μm was thermocompression-bonded on the surface of the insulating resin layer of the electromagnetic wave shielding film with an adhesive sheet (manufactured by Dexerias, D3410), thereby producing a test piece for a tensile test.

A jig of a tensile tester was attached to the polyimide film and the polyimide reinforcing plate of the test piece, and a peel test was performed under the conditions of a 180° peeling direction and a tensile speed of 50 mm/min according to JISZ0237.

[result]

In the test piece using the electromagnetic wave shielding film of Example 1, the peeling strength was 7.5 N/cm, and peeling occurred at the interface between the insulating resin layer and the metal thin film layer.

In the test piece using the electromagnetic wave shielding film of Example 2, the peeling strength was 7.2 N/cm, and peeling occurred at the interface between the insulating resin layer and the metal thin film layer.

In the test piece using the electromagnetic wave shielding film of Example 3, the peeling strength was 7.8 N/cm, and peeling occurred at the interface between the insulating resin layer and the metal thin film layer.

In the test piece using the electromagnetic wave shielding film of Example 4, the peeling strength was 7.3 N/cm, and peeling occurred at the interface between the insulating resin layer and the metal thin film layer.

In the test piece using the electromagnetic wave shielding film of Example 5, the peeling strength was 7.5 N/cm, and peeling occurred at the interface between the insulating resin layer and the metal thin film layer.

In the test piece using the electromagnetic wave shielding film of Example 6, the peeling strength was 5.3 N/cm, and peeling occurred at the interface between the insulating resin layer and the metal thin film layer.

In the test piece using the electromagnetic wave shielding film of Comparative Example 1, the peel strength was 3.5 N/cm, and interlayer peeling occurred between the insulating resin layer and the metal thin film layer.

From these results, it was found that the insulating resin layer composed of PEEK, PEKK, and PEI, which is a kind of aromatic polyether ketone, had better adhesion to the metal thin film layer than the insulating resin layer composed of the conventionally used thermosetting resin. powerful.

In the insulating resin layers of Examples 1 to 6, as the content of PEI increased with respect to PEEK, the glass transition temperature of the insulating resin layers increased. As reflected in this result, the appearance of the insulating resin layer of the produced electromagnetic wave shielding film became smoother and more favorable as the glass transition temperature increased. In addition, in the insulating resin layers of Examples 1 and 2 having a glass transition temperature of 160° C. or lower, there were waves on the surface of such an extent that they were barely recognizable by visual observation. This is caused by heat treatment (160° C.) for main curing of the anisotropic conductive sheet. This waviness, while not affecting peel strength, may impair appearance.

The films constituting the insulating resin layers of Examples 1 to 6 all had good tensile modulus at 160° C., and were hardly affected by the heat treatment during production and the high temperature environment during use. In particular, Examples 3 to 5 among Examples 1 to 6 were excellent in tensile modulus and excellent in peel strength.

Symbol Description

1 Electromagnetic wave shielding film,

2 Flexible printed circuit board with electromagnetic wave shielding film,

3 Flexible printed circuit boards with insulating films,

10 insulating resin layer,

22 metal film layer,

20 conductive layers,

24 Anisotropic conductive adhesive layer,

24a Thermosetting adhesives,

24b Conductive particles,

26 isotropic conductive adhesive layer,

26a Thermosetting adhesives,

26b Conductive particles,

30 carrier film,

32 carrier film body,

34 Adhesive layer,

40 release film,

42 Release film body,

44 release agent layer,

50 flexible printed circuit boards,

52 basement membrane,

54 printed circuits,

60 insulating film,

62 through holes.

Claims (11)

1. An electromagnetic wave shielding film comprising an insulating resin layer and a conductive layer containing a metal adjacent to the insulating resin layer, The insulating resin layer contains aromatic polyetherketone and polyetherimide. 2 . The electromagnetic wave shielding film according to claim 1 , wherein the aromatic polyetherketone is polyetheretherketone or polyetherketoneketone. 3 . 3. The electromagnetic wave shielding film according to claim 1 or 2, wherein the polyetherimide has a glass transition temperature of 200° C. or higher, and has a repeating unit represented by the following chemical formula (A);

4 . The electromagnetic wave shielding film according to claim 1 , wherein the content of the aromatic polyether ketone is 5% by mass or more and 95% by mass relative to the total mass of the insulating resin layer. 5 . Below, content of the said polyetherimide is 5 mass % or more and 95 mass % or less. 5 . The electromagnetic wave shielding film according to claim 1 , wherein the insulating resin layer has a thickness of 2 μm or more and 30 μm or less. 6 . 6 . The electromagnetic wave shielding film according to claim 1 , wherein the conductive layer is a metal vapor deposition layer. 7 . 7. The electromagnetic wave shielding film according to claim 6, wherein the metal vapor deposition layer is a silver vapor deposition layer or a copper vapor deposition layer. 8 . The electromagnetic wave shielding film according to claim 1 , further comprising a carrier film on the surface of the insulating resin layer opposite to the conductive layer. 9 . 9. A printed circuit board with an electromagnetic wave shielding film, comprising: A printed circuit board, which is provided with a printed circuit on at least one side of a substrate; an insulating film adjacent to the face of the printed wiring board on the side where the printed circuit is provided; and, The electromagnetic wave shielding film of any one of Claims 1-8 provided so that the said conductive layer and the said insulating film may adjoin. 10. A method for producing an electromagnetic wave shielding film, comprising the steps of: molding a mixed resin of aromatic polyetherketone and polyetherimide into a film shape, forming an insulating resin layer, and forming an insulating resin layer on one side of the insulating resin layer. A conductive layer is formed on the side. 11. A method of manufacturing a printed wiring board with an electromagnetic wave shielding film, comprising the step of: combining a printed wiring board with a printed circuit on at least one side of a substrate and the method according to any one of claims 1 to 8. The electromagnetic wave shielding film is crimped through the insulating film.

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