Conductive laminate and conductive laminate tape

Abstract

The present application is completed in view of the actual situation in the prior art, and aims to provide a conductive layered body and a conductive layered tape which are thin in total thickness, and can realize the balance of the conductive property, the electromagnetic wave shielding property, and the surface insulation and blackness. The present application provides a conductive layered body, comprising: a conductive layer having opposite first and second main surfaces; a black adhesive layer provided on the first main surface of the conductive layer; and an insulating portion provided on the black adhesive layer, wherein the conductive layer is a metal foil, the insulating portion has an insulating resin layer and a black ink layer, the lightness L* of the surface of the conductive layered body on the first main surface side of the conductive layer defined by the CIE L*a*b* color system is 20 or more and 27 or less, the chroma a* is -2 or more and 2 or less, and the chroma b* is -2 or more and 2 or less.

Description

Technical Field

[0001] This invention relates to conductive laminates and conductive laminated tapes. Background Technology

[0002] Conductive laminates and conductive laminates with conductive adhesive layers provided thereon (hereinafter, conductive laminates and conductive laminates are sometimes collectively referred to as conductive laminates, etc.) are used for shielding unwanted leakage electromagnetic waves radiated from electrical and electronic equipment, shielding harmful spatial electromagnetic waves generated by other electrical and electronic equipment, and grounding to prevent static electricity, etc., based on their ease of processing.

[0003] With the miniaturization and thinning of electrical and electronic equipment, there is a demand for conductive laminates and the like to have a small overall thickness and be thin. In addition to high conductivity, conductive laminates and the like are required to have insulation on one surface in order to ensure high electromagnetic wave shielding and prevent short circuits caused by contact with other components.

[0004] Furthermore, in recent years, electrical and electronic equipment has sought to improve its appearance and internal design, the quality of displayed images, and the visual recognizability of images. In particular, there has been an attempt to unify the color of electronic components built into the device to black, thereby improving internal design. Therefore, conductive laminates used in parts requiring such internal design are required to exhibit a high degree of surface blackness, such as jet blackness or matte finish, to achieve a sense of unity with the black electronic components. In addition, in this specification, the surface blackness of conductive laminates, etc., refers to the physical property that is primarily visually discernible from the insulating side of the conductive laminate, etc.

[0005] For example, Patent Document 1 discloses a conductive sheet comprising: a substrate having metal layers formed on both sides of a resin film; a light-shielding insulating layer disposed on a first main surface of the substrate; and a conductive adhesive layer disposed on a second main surface of the substrate. The conductive sheet disclosed in Patent Document 1 uses a black resin layer formed from an insulating resin colored with a black colorant as the light-shielding insulating layer.

[0006] In addition, Patent Document 2 discloses a sheet in which an adhesive tape having a colored layer on one side of a polyethylene terephthalate film and a transparent adhesive layer on the other side is attached to a first main surface of a soft aluminum substrate, and an additional transparent adhesive layer is provided on a second main surface of the soft aluminum substrate.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2014-58108

[0010] Patent Document 2: Japanese Patent Application Publication No. 2017-8262 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] The conductive sheet disclosed in Patent Document 1 has a structure in which a resin film is separated between two metal layers on a substrate, and each metal layer is thin. Therefore, it is difficult to achieve sufficient conductivity and electromagnetic wave shielding, especially electromagnetic wave shielding, in the aforementioned conductive sheet. Furthermore, to improve these properties, the thickness of the metal layers must be increased, presenting a challenge in balancing improved conductivity and electromagnetic wave shielding with a thinner conductive sheet. Additionally, in the conductive sheet disclosed in Patent Document 1, the light-shielding insulating layer, i.e., the black resin layer, is formed directly on the metal layer. However, to achieve high insulation and a black surface, the thickness of the black resin layer must be increased, presenting a challenge in balancing improved surface insulation and a black surface with a thinner conductive sheet.

[0013] The sheet disclosed in Patent Document 2 only ensures surface blackness through a thin coloring layer, making it difficult to achieve sufficient surface blackness. Furthermore, to improve the aforementioned characteristics, the thickness of the coloring layer must be increased, presenting a challenge of balancing improved surface blackness with the thinning of the conductive sheet.

[0014] The present invention was made in view of the above-mentioned actual situation, and its purpose is to provide a conductive laminate and conductive laminate tape that have a small total thickness and are thin, and can achieve a balance of conductivity, electromagnetic wave shielding, surface insulation and blackness.

[0015] Technical solutions for solving the problem

[0016] The present invention provides a conductive laminate comprising: a conductive layer having a first main surface and a second main surface facing each other; a black adhesive layer disposed on the first main surface of the conductive layer; and an insulating portion disposed on the black adhesive layer. The conductive layer is a metal foil, and the insulating portion comprises an insulating resin layer and a black ink layer. The lightness L* of the surface of the conductive laminate located on the first main surface side of the conductive layer, as defined by the CIE L*a*b* color system, is 20 or more and 27 or less, the chromaticity a* is -2 or more and 2 or less, and the chromaticity b* is -2 or more and 2 or less.

[0017] In addition, the present invention provides a conductive laminate tape having the above-described conductive laminate and a conductive adhesive layer, wherein the conductive adhesive layer is disposed on the second main surface of the conductive layer constituting the conductive laminate.

[0018] Invention Effects

[0019] According to the present invention, conductive laminates and conductive laminates with small total thickness and thin profiles are provided, which can achieve a balance of various properties such as conductivity, electromagnetic wave shielding, surface insulation and blackness. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view illustrating an example of the conductive laminate of the present invention.

[0021] Figure 2 This is a schematic cross-sectional view illustrating other examples of conductive laminates of the present invention.

[0022] Figure 3 This is a schematic cross-sectional view illustrating an example of the conductive laminated strip of the present invention.

[0023] Figure 4 This is a schematic cross-sectional view illustrating other examples of the conductive laminated strip of the present invention.

[0024] Figure 5 This is a diagram illustrating the outline of the specimen used in the measurement method for electromagnetic wave shielding characteristics.

[0025] Figure 6 This is a diagram illustrating the general method for measuring electromagnetic wave shielding characteristics. Detailed Implementation

[0026] The conductive laminate and conductive laminate tape of the present invention will be described below.

[0027] I. Conductive laminate

[0028] The conductive laminate of the present invention comprises: a conductive layer having opposing first main surfaces and second main surfaces; a black adhesive layer disposed on the first main surface of the conductive layer; and an insulating portion disposed on the black adhesive layer, wherein the conductive layer is a metal foil and the insulating portion comprises an insulating resin layer and a black ink layer.

[0029] The conductive laminate of the present invention has a layer structure comprising an insulating portion having a black ink layer and an insulating resin layer, a black adhesive layer, and a metal foil as a conductive layer, which are sequentially stacked. It has a small total thickness and is thin, and exhibits high conductivity, high electromagnetic wave shielding, and high surface insulation. Furthermore, according to the present invention, by having the above-described stack structure in the conductive laminate, the lightness L*, chromaticity a*, and b* of the insulating portion side surface of the conductive laminate can be kept within a given range, thereby improving its blackness.

[0030] In other words, the lightness L* of the conductive laminate located on the first main surface side of the conductive layer of the present invention, as defined by the CIE L*a*b* color system, is 20 or more and 27 or less, the chromaticity a* is -2 or more and 2 or less, and the chromaticity b* is -2 or more and 2 or less.

[0031] According to the present invention, a conductive laminate with a small total thickness and thin profile can be provided, which can achieve a balance of various properties such as conductivity, electromagnetic wave shielding, surface insulation and blackness.

[0032] In more detail, according to the conductive laminate of the present invention, by having the above-described layer structure, the black ink layer and the black adhesive layer, which form the outermost insulating layer, overlap when viewed from above. Therefore, even with a small total thickness of the conductive laminate, a high degree of surface blackness can be achieved. Especially when using metal foil as the conductive layer, the color concentration and hue of the black on the surface of the conductive laminate are easily affected by the color of the metal foil, making it difficult to achieve a jet-black, matte, or other black design qualities. In contrast, according to the present invention, by using two layers—a black ink layer and a black adhesive layer—to ensure blackness, the overlapping of the two black layers suppresses the influence of the metal foil's color, improving surface blackness, especially jet-black, matte, and other black design qualities. Furthermore, according to the conductive laminate of the present invention, by using different layers for the black ink layer that contributes to surface blackness and the insulating resin layer that contributes to insulation, surface blackness can be improved, and high insulation can be ensured. Moreover, by using metal foil as the conductive layer, good electromagnetic wave shielding can be achieved even with a small total thickness.

[0033] In this invention, the overall surface blackness of the conductive laminate is achieved by overlapping two layers: a black ink layer and a black adhesive layer. However, as a method for achieving surface blackness, for example, a method could be considered where a black ink layer is formed directly on the conductive layer, and the black ink layer is used as a single layer for display. However, in this method, it is necessary to ensure not only surface blackness but also surface insulation through the black ink layer. Even if the surface blackness can be improved by reducing the total thickness of the conductive laminate, it is sometimes difficult to achieve the desired surface insulation. Furthermore, to improve insulation, the thickness of the black ink layer must be increased, which can sometimes make it difficult to reduce the total thickness of the conductive laminate.

[0034] As another method to achieve a black surface finish, it is also possible to add a black colorant to an insulating resin layer that ensures insulation, without setting a black ink layer or a black adhesive layer. However, in this method, to achieve a black surface finish, it is necessary to increase the amount of black colorant added. Sometimes, due to the conductivity of the colorant, the insulation of the insulating resin layer may decrease. In addition, if a large amount of colorant is added, it is difficult to extend the insulating resin layer to the desired thinness. Due to the increased thickness of the insulating resin layer, it is sometimes difficult to reduce the total thickness of the conductive laminate.

[0035] Thus, according to the method of displaying surface blackness, there are problems such as hindering the overall thinning of the laminate and reducing physical properties such as conductivity, insulation, and electromagnetic wave shielding. On the other hand, if the requirements for thinness, conductivity, insulation, and electromagnetic wave shielding are to be met, there is a drawback that sufficient surface blackness cannot be obtained. In order to eliminate these drawbacks, the inventors conducted in-depth research and as a result, by setting up a layer structure consisting of an insulating part having a black ink layer and an insulating resin layer, a black adhesive layer, and a metal foil as a conductive layer, which are stacked in sequence, a conductive laminate with a small total thickness and thinness is achieved, which can simultaneously achieve conductivity, electromagnetic wave shielding, surface insulation, and blackness.

[0036] The conductive laminate of the present invention sequentially comprises an insulating portion having a black ink layer and an insulating resin layer, a black adhesive layer, and a conductive layer. Each layer will be described below.

[0037] Furthermore, in the conductive laminate of the present invention, the surface of the conductive laminate located on the first main surface side of the conductive layer is sometimes referred to as the insulating portion side surface of the conductive laminate. Additionally, the surface of the conductive laminate located on the second main surface side of the conductive layer is sometimes referred to as the conductive layer side surface of the conductive laminate.

[0038] (Conductive layer)

[0039] The conductive layer in this invention is the layer that bears the conductivity of the conductive laminate. In this invention, the conductive layer is a metal foil. Here, metal foil refers to a layer made of metal, specifically a foil formed with a thickness on the order of micrometers. By using a metal foil as the conductive layer, the conductive laminate of this invention can exhibit higher electromagnetic wave shielding compared to graphite sheets, metal vapor-deposited films, etc.

[0040] There are no particular limitations on the metal foil as long as it is made of a desired metallic material; examples include copper foil, aluminum foil, nickel foil, and stainless steel foil. However, from the viewpoint of excellent conductivity and electromagnetic wave shielding properties, copper foil is the most preferred.

[0041] In addition, the copper foil can be electrolytic copper foil or rolled copper foil, but electrolytic copper foil is the best because of the excellent adhesion of the black adhesive layer bonded to the conductive layer when it is formed into a conductive laminate tape described later.

[0042] The thickness of the conductive layer is only required to achieve the desired conductivity of the conductive laminate of the present invention. Specifically, the thickness of the conductive layer is preferably 15 μm or more, more preferably 20 μm or more, and preferably 40 μm or less, more preferably 35 μm or less. More specifically, the thickness of the conductive layer is preferably 15 μm or more and 40 μm or less, more preferably 20 μm or more and 35 μm or less. This is because by keeping the thickness of the conductive layer within the above-mentioned range, conductivity and electromagnetic wave shielding can be well achieved even if the total thickness of the conductive laminate is small. Furthermore, if the thickness of the conductive layer exceeds the above-mentioned range, it is sometimes difficult to make the conductive laminate thinner; on the other hand, if the above-mentioned range is not met, conductivity and electromagnetic wave shielding can sometimes be difficult to obtain.

[0043] The ten-point average surface roughness Rz of the conductive layer is preferably 2.0 μm or less. This is because, by keeping the surface roughness Rz of the conductive layer within the aforementioned range, sufficient adhesion can be achieved to the black adhesive layer bonded to the conductive layer, the conductive adhesive layer of the film bonded to the second main surface of the conductive layer when formed as a conductive laminate tape described later, and the insulating adhesive layer. More preferably, the ten-point average surface roughness Rz of the conductive layer is 0.01 μm or more or 0.1 μm or more; furthermore, Rz is 2.0 μm or less, 1.5 μm or less, 1.3 μm or less, 1.1 μm or less, or 0.9 μm or less.

[0044] Furthermore, the arithmetic mean roughness Ra of the conductive layer is preferably 0.01 μm or more and 1.0 μm or less, more preferably 0.01 μm or more and 0.7 μm or less, and even more preferably 0.05 μm or more and 0.3 μm or less. This is because, by setting the arithmetic mean roughness Ra of the conductive layer within the aforementioned range, sufficient adhesion can be achieved to the black adhesive layer bonded to the conductive layer, the conductive adhesive layer of the film bonded to the second main surface of the conductive layer during the formation of the conductive laminate tape described later, and the insulating adhesive layer.

[0045] The ten-point average surface roughness Rz and arithmetic mean roughness Ra of the conductive layer refer to the values ​​specified in JIS B0601:2013. Using a HANDYSURF+ manufactured by Tokyo Seimitsu Corporation, surface measurements are performed at any three points on the surface of the conductive layer (each measuring 50 μm in length × 50 μm in width). The average value of the three measured points is taken as the ten-point average surface roughness Rz and arithmetic mean roughness Ra of the conductive layer.

[0046] (Black adhesive layer)

[0047] In this invention, a black adhesive layer is disposed between the conductive layer and the insulating portion, serving as a bonding layer between the two. In addition to the black ink layer present in the insulating portion, the adhesive layer bonding the conductive layer and the adhesive layer in the conductive laminate of this invention is black. When viewed from above, the black ink layer and the black adhesive layer overlap, thereby improving the surface blackness, particularly the black design aesthetics, visually perceptible from the insulating portion side surface. This also helps to suppress the increase in the overall thickness of the conductive laminate that accompanies the improved surface blackness.

[0048] The black adhesive layer comprises at least a black pigment and an adhesive component. The adhesive component is not particularly limited; for example, well-known adhesive compositions such as acrylic adhesive compositions, rubber adhesive compositions, silicone adhesive compositions, polyurethane adhesive compositions, polyester adhesive compositions, styrene-diene block copolymer adhesive compositions, vinyl alkyl ether adhesive compositions, polyamide adhesive compositions, fluorinated adhesive compositions, creep-modified adhesive compositions, and radiation-cured adhesive compositions may be appropriately selected. The adhesive component may be used alone or in combination of two or more.

[0049] Preferably, the adhesive composition includes an acrylic adhesive composition as an adhesive component. The acrylic adhesive composition is a (meth)acrylic polymer (acrylic copolymer) as the base polymer and includes appropriate additives such as crosslinking agents, tackifiers, softeners, plasticizers, fillers, anti-aging agents, and colorants as needed. It is preferred because of its high bonding reliability.

[0050] (Meth)acrylate polymers are polymers with alkyl (meth)acrylate monomers as the main component, and are prepared by using monomers (copolymeric monomers) that can copolymerize with (meth)alkyl esters, as needed. That is, acrylic polymers can be homopolymers or copolymers.

[0051] Examples of alkyl methacrylates constituting (meth)acrylate polymers include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, nonyl methacrylate, and so on. Isononyl acrylate, decyl acrylate, isodecyl acrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, octadecyl acrylate, nonadecanyl acrylate, eicosyl acrylate, etc. (C1-20 alkyl esters of methacrylate [preferably C4-18 alkyl esters of methacrylate (straight-chain or branched alkyl)], etc. Alkyl acrylates can be appropriately selected based on the desired adhesion, etc. Alkyl acrylates can be used alone or in combination of two or more. When containing 30% or more butyl acrylate, it is preferred due to its excellent adhesion and heat resistance.

[0052] In addition, examples of comonomers capable of copolymerizing with the aforementioned (meth)alkyl esters include: (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and other carboxyl-containing monomers or their anhydrides; sodium vinyl sulfonate and other monomers containing sulfonic acid groups; styrene, substituted styrene, and other aromatic vinyl compounds; acrylonitrile and other monomers containing cyano groups; olefins such as ethylene, propylene, and butadiene; vinyl esters such as vinyl acetate; vinyl chloride; acrylamide, methacrylamide, N-vinylpyrrolidone, N,N-dimethyl(meth)acrylamide, and other monomers containing amide groups; hydroxyl-containing monomers such as (meth)acrylate hydroxyalkyl esters and glyceryl ester dimethacrylate; and amino-containing monomers such as (meth)acrylate aminoethyl ester and (meth)acrylate morpholine. Monomers containing imino groups, such as cyclohexylmaleimide and isopropylmaleimide; epoxy-containing monomers, such as glycidyl methacrylate and methyl glycidyl methacrylate; and, in addition to isocyanate-containing monomers such as 2-methacryloyloxyethyl isocyanate, multifunctional copolymers such as triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and divinylbenzene. A single copolymer monomer or a combination of two or more monomers can be used. Modifying monomers with functional groups such as carboxyl groups are preferred as copolymer monomers. When it contains 0.5% to 4.0% acrylic acid, it is preferred because of its excellent adhesion and heat resistance.

[0053] Preferably, the weight-average molecular weight (Mw) of the (meth)acrylic polymer is 300,000 or more, 500,000 or more, or 600,000 or more; furthermore, the aforementioned weight-average molecular weight (Mw) is preferably 1,200,000 or less, 1,000,000 or less, or 900,000 or less. More specifically, the weight-average molecular weight (Mw) of the (meth)acrylic polymer is preferably in the range of 300,000 to 1,200,000, more preferably in the range of 500,000 to 1,000,000, and even more preferably in the range of 600,000 to 900,000. By ensuring that the weight-average molecular weight (Mw) of the (meth)acrylic polymer is within the above-mentioned range, the aforementioned black adhesive layer, even in its thin thickness, can exhibit good adhesion and heat resistance to the conductive layer and the insulating portion.

[0054] Weight-average molecular weight (Mw) can be measured by gel permeation chromatography (GPC). More specifically, the GPC measuring device can be the "SC8020" manufactured by Tosoh Corporation, which measures the molecular weight using polystyrene conversion values ​​under the following GPC measurement conditions.

[0055] (GPC measurement conditions)

[0056] • Sample concentration: 0.5% by weight (tetrahydrofuran solution)

[0057] • Sample injection volume: 100 μL

[0058] • Eluent: Tetrahydrofuran (THF)

[0059] • Flow rate: 1.0 mL / min

[0060] • Column temperature (measurement temperature): 40℃

[0061] • Pillar: "TSKgel GMHHR-H" manufactured by Tosoh Corporation

[0062] • Detector: Differential refraction

[0063] In addition, unless otherwise specified, the weight-average molecular weight (Mw) in this specification is the value measured by the methods and conditions described above.

[0064] The black adhesive layer in this invention achieves its black color by including a black colorant. Examples of black colorants include organic black pigments, inorganic black pigments, and black dyes. One type of black colorant can be used alone, or in combination of two or more. Furthermore, the black colorant preferably has low insulating or conductive properties. This is because low conductivity in the black adhesive layer improves the surface insulation of the conductive laminate.

[0065] Examples of inorganic black pigments include carbon black (furnace black, channel black, acetylene black, thermal black, lampblack, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, anthocyanin black, activated carbon, ferrite, magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complexes, and composite oxide black pigments. Examples of organic black pigments include aniline black, azo pigments, and anthraquinone organic black pigments. Among these, carbon black is preferred due to its excellent opacity and dispersibility, and the high opacity resulting from the overlap of the black ink layer and the black binder layer.

[0066] The content of black colorant in the black adhesive layer is not particularly limited, and can be the amount that enables the desired surface blackness to be achieved through overlap with the black ink layer. For example, in the total amount (100% by mass) of the black adhesive layer, it is preferably 1% by mass or more and 50% by mass or less, more preferably 4% by mass or more and 40% by mass or less, and even more preferably 10% by mass or more and 35% by mass or less. By keeping the content of black colorant in the black adhesive layer within the above range, even with a thin layer, the insulating properties of the black adhesive layer and its adhesion to insulating and conductive layers can be achieved, thereby improving the surface blackness resulting from overlap with the black ink layer.

[0067] To improve adhesion, the black adhesive layer preferably contains a tackifying resin. By including a tackifying resin in the black adhesive layer, tensile strength and tensile breaking strength can be improved. The tensile strength and tensile breaking strength of the conductive laminate of the present invention can be adjusted by appropriately adding a tackifying resin according to the (meth)acrylic polymer used. Examples of tackifying resins include: rosin-based resins such as rosin and rosin ester compounds; terpene-based resins such as diterpene polymers and α-pinene-phenol copolymers; petroleum resins such as aliphatic (C5) and aromatic (C9) resins; and also styrene-based resins, phenolic resins, xylene resins, etc. One tackifying resin can be used alone, or two or more can be used in combination.

[0068] In cases where the aforementioned black adhesive layer contains a (meth)acrylate polymer with (meth)acrylate as the main monomer component (in other words, (meth)acrylate), it is preferable to mix in a mixture containing rosin-based resin and styrene-based resin. This is because by using both of these two tackifying resins together, it is easier to achieve both a thinner black adhesive layer and good adhesion.

[0069] To improve initial adhesion, the aforementioned black adhesive layer preferably contains a tackifying resin that is liquid at room temperature. Examples of tackifying resins that are liquid at room temperature include liquid resins that are solid at room temperature, processing oils, polyester plasticizers, and low molecular weight liquid rubbers such as polybutene. Terpene phenolic resins are particularly preferred. Commercially available examples include YP-90L manufactured by Yasuhara Chemical Co., Ltd. The amount of tackifying resin added is preferably 1 to 20 parts by weight relative to 100 parts by weight of the (meth)acrylic polymer.

[0070] The aforementioned tackifying resin preferably comprises 10 to 70 parts by weight of (meth)acrylic polymer per 100 parts by weight, more preferably 20 to 60 parts by weight. By setting the amount of tackifying resin within the above range, the adhesive strength of the black adhesive layer can be improved.

[0071] The gel content of the black adhesive layer is not particularly limited, but is preferably in the range of 5% to 95% by mass. This is because even if the black adhesive layer is thin, it is easy to exhibit sufficient adhesion. More preferably, the gel content of the black adhesive layer is in the range of 10% to 70% by mass, and even more preferably in the range of 15% to 50% by mass.

[0072] For the gel fraction, the cured black adhesive layer is immersed in toluene, and the mass of the remaining insoluble components after drying is measured after 24 hours. The result is expressed as a percentage of the original mass.

[0073] Gel fraction (mass%) = [(mass of black adhesive layer after toluene impregnation) / (mass of black adhesive layer before toluene impregnation)] × 100

[0074] The energy storage modulus of the black adhesive layer at 25°C is preferably 1×10⁻⁶. 4 Pa or higher and 5×10 5 Pa or less, more preferably 3×10 Pa 4 Pa or higher and 1×10 5 Below Pa. This is because, by making the storage modulus of the black adhesive layer within the range described above, even thin films can easily achieve a high balance between wettability (initial tack), adhesion, and processability.

[0075] The storage modulus of the black adhesive layer at 25°C can be measured using a viscoelastic testing machine. More specifically, the viscoelastic testing machine can be a viscoelastic testing machine (ARES2kSTD) manufactured by TA Instrument Japan, and the value can be determined by measuring under the following conditions.

[0076] • Test piece thickness: 2mm

[0077] • Frequency: 1Hz

[0078] • Compression load: 40~60g

[0079] Furthermore, unless otherwise specified, the storage modulus of the black adhesive layer and other adhesive layers at 25°C in this specification is the value measured using the methods and conditions described above.

[0080] (Meth)acrylic acid polymers can be prepared using conventional polymerization methods such as solution polymerization, emulsion polymerization, and ultraviolet irradiation polymerization.

[0081] The thickness of the black adhesive layer is preferably 0.5 μm or more, 1 μm or more, or 1.5 μm or more; furthermore, the aforementioned thickness is preferably 5 μm or less, 3 μm or less, or 2.5 μm or less. More specifically, the thickness of the black adhesive layer is preferably 0.5 μm or more and 5 μm or less, more preferably 1 μm or more and 3 μm or less, and most preferably 1.5 μm or more and 2.5 μm or less. This is because by making the thickness of the black adhesive layer within the aforementioned range, the blackness of the black adhesive layer monomer is improved, and it is also easier to balance the adhesive strength and thinness as a conductive laminate. In particular, when the conductive laminate of the present invention is used as an electromagnetic wave shielding material for electronic components, it is easy to balance the required adhesive strength and thinness.

[0082] The black adhesive layer preferably has low conductivity or exhibits insulating properties. This is because by making the black adhesive layer have low conductivity, the insulation properties of the insulating side surface of the conductive laminate can be improved. Specifically, the surface resistivity of the black adhesive layer is preferably 1 × 10⁻⁶. 9 Ω / □ or higher, more preferably 1×10 10 Ω / □ or higher, further preferably 1×10 11 Ω / □ or higher. By ensuring the surface resistivity of the black adhesive layer is within the aforementioned range, the black adhesive layer can exhibit high insulation properties, thereby further enhancing the insulation performance through the insulating portion. Consequently, the conductive laminate of the present invention exhibits higher insulation properties on the insulating portion side surface. Furthermore, a higher surface resistivity of the black adhesive layer is preferable, but it is typically set to 1×10⁻⁶. 18 Ω / □ or less, 1×10 16 Ω / □ or less, 1×10 14 Ω / □ or less, 1×10 12 Below Ω / □.

[0083] The surface resistivity of the black adhesive layer refers to the value measured according to JIS-K6911. It can be measured using a resistivity meter (Advantest manufactures digital ultra-high resistance / micro current meters R8340 and TR42 boxes) by applying a voltage of 500V to the black adhesive layer.

[0084] The opacity of the black adhesive layer is not particularly limited as long as it is sufficient to achieve the desired surface blackness through overlap with the black ink layer described later, but it is preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more. Furthermore, the higher the opacity of the black adhesive layer, the more preferred it is, and its upper limit can be set to 100%. This is because by setting the opacity of the black adhesive layer within the aforementioned range, the decrease in blackness of the conductive laminate surface caused by the color of the conductive layer can be suppressed.

[0085] The shading rate of the black adhesive layer can be measured using the following method. The black adhesive layer is attached to both the white and black sides of shading rate test paper (manufactured by Japan Test Panel Industry Co., Ltd.). The Y value, representing luminance, of the tristimulus values ​​of the black adhesive layer attached to the white and black sides is measured using the color measurement method specified in JIS-Z-8722. A standard light C is measured in a 2-degree field of view using a colorimeter "CM-3500d" (manufactured by Minolta). The shading rate can be measured by substituting the measured Y value into the following formula.

[0086] Opacity (%) = (Y value of black adhesive layer attached to black side / Y value of black adhesive layer attached to white side) × 100%

[0087] The black adhesive layer can be formed by coating an adhesive containing a black colorant onto a conductive layer or resin film. Examples of coating methods include gravure coating, comma coating, rod coating, die coating, lip coating, and screen coating. Among these, gravure coating is preferred for coating thin films, and microgravure coating is most preferred.

[0088] (Insulation section)

[0089] The insulating portion of the present invention is a layer disposed on the first main surface of the conductive layer through a black adhesive layer. Furthermore, the aforementioned insulating portion serves as the outermost layer of the conductive laminate of the present invention. The insulating portion of the present invention comprises an insulating resin layer and a black ink layer.

[0090] In the conductive laminate of the present invention, the stacking order of the insulating resin layer and the black ink layer in the insulating portion is not limited. The black ink layer and the insulating resin layer may be stacked sequentially from the black adhesive layer side, or the insulating resin layer and the black ink layer may be stacked sequentially from the black adhesive layer side.

[0091] Figure 1 This is a schematic cross-sectional view illustrating an example of a conductive laminate of the present invention, showing an example in which the above-described insulating resin layer and the above-described black ink layer are sequentially laminated from the black adhesive layer side. Figure 1 The conductive laminate 10 of the present invention illustrated herein includes: a conductive layer 1 having opposing first main surfaces and second main surfaces; a black adhesive layer 2 disposed on the first main surface of the conductive layer 1; and an insulating portion 3 disposed on the black adhesive layer 2 and having an insulating resin layer 4 and a black ink layer 5. The conductive layer 1 is a metal foil, and the insulating resin layer 4 and the black ink layer 5 are sequentially laminated from the black adhesive layer 2 side.

[0092] in addition, Figure 2This is a schematic cross-sectional view illustrating another example of the conductive laminate of the present invention, showing an example in which the aforementioned black ink layer and the aforementioned insulating resin layer are sequentially laminated from the black adhesive layer side. Figure 2 The conductive laminate 10 of the present invention illustrated herein includes: a conductive layer 1 having opposing first main surfaces and second main surfaces; a black adhesive layer 2 disposed on the first main surface of the conductive layer 1; and an insulating portion 3 disposed on the black adhesive layer 2 and having an insulating resin layer 4 and a black ink layer 5. The conductive layer 1 is a metal foil, and the insulating resin layer 4 and the black ink layer 5 are sequentially laminated from the side of the black adhesive layer 2.

[0093] Preferably, the insulating portion comprises the insulating resin layer and the black ink layer sequentially stacked from the black adhesive layer side. This is because by placing the black ink layer on the side opposite to the conductive layer side of the insulating resin layer, the black ink layer is positioned on the outermost side of the conductive laminate, allowing for further adjustment of the surface blackness of the conductive laminate overlapping with the black adhesive layer.

[0094] The insulating resin layer constituting the insulating part of the present invention is not particularly limited, but resin films exhibiting known insulating properties can be listed. Specifically, polyester films, polyimide films, polyamide films, polyurethane films, polyolefin films, etc., can be listed. Among these, polyester films or polyimide films are preferred because they can maintain insulation while easily exhibiting strength that is not easily broken at a thin thickness. Polyester films are particularly preferred because they can be further thinned and have excellent insulation properties.

[0095] The thickness of the insulating resin layer is not particularly limited as long as it achieves the desired insulation performance, but it is preferably 1 μm or more, 1.5 μm or more, or 2 μm or more. Furthermore, it is more preferably 5 μm or less, 4.5 μm or less, 4 μm or less, 3.5 μm or less, 3 μm or less, or 2.5 μm or less. More specifically, the thickness of the insulating resin layer is preferably 1 μm or more and 5 μm or less, more preferably 1 μm or more and 3 μm or less, and most preferably 1.5 μm or more and 2.5 μm or less. This is because by keeping the thickness of the insulating resin layer within the above range, high insulation performance is easily achieved.

[0096] Furthermore, the black ink layer constituting the insulating portion in this invention comprises at least a black pigment and an adhesive resin. The black ink layer is formed by dispersing a known black pigment in a resin varnish.

[0097] Black pigments can be used alone or in combination of two or more. Furthermore, black pigments are preferably low in insulation or conductivity. This is because low conductivity in the black ink layer improves the surface insulation of the conductive laminate.

[0098] As black pigments, known materials can be used, including both organic and inorganic black pigments. Examples of inorganic black pigments include carbon black (furnace black, channel black, acetylene black, thermal black, lampblack, etc.), graphite, metal oxides (chromium oxide, iron oxide, copper oxide, manganese dioxide, etc.), aniline black, perylene black, titanium black, anthocyanin black, activated carbon, ferrite, magnetite, molybdenum disulfide, chromium complexes, and complex oxide-based black pigments. Examples of organic black pigments include aniline black, azo pigments, and anthraquinone-based organic black pigments.

[0099] The black ink layer preferably comprises at least one of carbon black and an azo pigment. This is because carbon black improves blackness and is therefore preferred. Additionally, azo pigments improve insulation and are therefore preferred. More preferably, it comprises both carbon black and an azo pigment.

[0100] The amount of black pigment should be such that the desired blackness, especially the black design quality, can be achieved through the overlap of the black ink layer and the black binder layer. For example, it is preferably 1% to 95% by mass of the total amount of the black ink layer (100% by mass), preferably 10% to 90% by mass, and preferably 20% to 80% by mass. This is because by setting the black pigment content within the above range, the black ink layer can exhibit the desired surface blackness.

[0101] The adhesive resin can be any known resin used in inks, and can be used alone or in combination of two or more. Examples of adhesive resins include polyurethane resin, polyester resin, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, and nitrocellulose resin. Among these, polyurethane resin or polyester resin is preferred due to its excellent adhesion, and polyurethane resin is more preferred due to its flexibility and good adhesion to the insulating resin layer.

[0102] Polyurethane resin is obtained through a polycondensation reaction of diisocyanate compounds, polyol compounds, and low molecular weight chain extenders, and is a flexible and elastic resin with multiple polyurethane bonds within its molecule. The weight-average molecular weight of polyurethane resins used as adhesive resins is preferably in the range of 1,000 to 500,000, more preferably in the range of 30,000 to 100,000.

[0103] Examples of diisocyanate compounds used to form polyurethane resins include, for example, methylene diisocyanate, isopropylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and chain aliphatic diisocyanates such as diisocyanates in which the carboxyl group of a dimer acid is replaced with an isocyanate group; cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-di(isocyanate-methyl)cyclohexane, and methylcyclohexane diisocyanate; and cyclic aliphatic diisocyanates such as 4... These include dialkyl diphenylmethane diisocyanates such as 4'-diphenyldimethylmethane diisocyanate, tetraalkyl diphenylmethane diisocyanates such as 4,4'-diphenyltetramethylmethane diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, 1,3-phenyl diisocyanate, 1,4-phenyl diisocyanate, toluene diisocyanate, xylene diisocyanate, m-tetramethylphenyldimethylmethylene diisocyanate, and other aromatic diisocyanates, as well as amino acid diisocyanates such as lysine diisocyanate. The aforementioned polyisocyanate compounds, primarily composed of these diisocyanate compounds, can be used alone or in combination of two or more.

[0104] Examples of polyol compounds used to form polyurethane resins include polyether polyols, polyester polyols, polycarbonate polyols, and polybutadiene polyols. Examples of polyether polyols include polyethylene glycol, polypropylene glycol, and polyoxytetramethylene ether glycol, obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. Examples of polyester polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4-butanediol, dipropylene glycol, bisphenol A, hydrogenated bisphenol A, and other saturated or unsaturated low molecular weight diols, as well as dicarboxylic acids such as adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, octanoic acid, etc., obtained by dehydration condensation of these dicarboxylic acids or their corresponding anhydrides.

[0105] In addition to the aforementioned black pigment and adhesive resin, the black ink layer may also contain known materials used in general ink compositions. Known materials include, for example, dispersants such as cellulose resins, various isocyanate-based curing agents, particulate anti-caking agents such as silica, calcium carbonate, calcium phosphate, talc, polyurethane beads, acrylic beads, and silicone beads, and anti-caking agents based on organic compounds such as polyethylene wax (PE wax), fatty acid amides, fatty acid esters, and higher fatty acids.

[0106] The thickness of the black ink layer is only required to achieve the desired black design through overlap with the black adhesive layer. Specifically, the thickness of the black ink layer is preferably 1 μm or more, 1.2 μm or more, or 1.5 μm or more, and preferably 3 μm or less, 2.5 μm or less, or 2 μm or less. More specifically, the thickness of the black ink layer is preferably 1 μm or more and 3 μm or less, more preferably 1 μm or more and 2 μm or less, and even more preferably 1.2 μm or more and 2 μm or less. This is because by keeping the thickness of the black ink layer within the above range, both thinness and surface blackness can be achieved.

[0107] The opacity of the black ink layer is not particularly limited as long as it achieves the desired surface blackness through overlap with the aforementioned black adhesive layer, but it is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. Furthermore, the higher the opacity of the black ink layer, the better; its upper limit can be set to 100%. By setting the opacity of the black ink layer within the aforementioned range, the influence of the conductive layer's color on the surface of the conductive laminate is suppressed, making it easier to control the blackness.

[0108] The opacity of the black ink layer can be measured using the same method as that used to measure the opacity of the black adhesive layer.

[0109] In addition to the aforementioned black ink layer and insulating resin layer, the insulating portion of the present invention may also include a matte layer. By providing a matte layer, various physical properties such as lightness L*, chromaticity a*, chromaticity b*, and 60° gloss value can be adjusted. In particular, a matte layer is preferred for adjusting the 60° gloss value.

[0110] The matte layer is a layer comprising a resin binder and microparticles. Examples of common microparticles include silica, calcium carbonate, and barium sulfate. Furthermore, a resin commonly used in matte layers can be used as the resin binder. Preferably, the matte layer contains silica particles dispersed in a polyurethane-based resin.

[0111] The thickness of the matting layer is not particularly limited as long as it achieves the desired function, but is preferably 0.3 μm or more, 0.4 μm or more, or 0.5 μm or more. Furthermore, the thickness of the matting layer is acceptable as long as it does not significantly affect the overall thickness of the conductive laminate, and is preferably 3 μm or less, 2 μm or less, or 1.5 μm or less. More specifically, the thickness of the matting layer is preferably 0.3 μm or more and 3 μm or less, and more preferably 0.5 μm or more and 1.5 μm or less.

[0112] When the insulating portion also has a matte layer, the insulating portion can be sequentially laminated with the insulating resin layer, the black ink layer, and the matte layer from the black adhesive layer side, or sequentially laminated with the black ink layer, the insulating resin layer, and the matte layer from the black adhesive layer side. Preferably, the insulating portion is sequentially laminated with the insulating resin layer, the black ink layer, and the matte layer from the black adhesive layer side. This is because the black ink layer and the matte layer can be used to further adjust the surface blackness of the conductive laminate formed by overlapping with the black adhesive layer.

[0113] The total thickness of the insulating portion of the present invention is preferably 3 μm or more and 10 μm or less, more preferably 4 μm or more and 8 μm or less, and even more preferably 5 μm or more and 7 μm or less. This is because by making the total thickness of the insulating portion within the above range, the insulating and black properties of the insulating portion can be balanced.

[0114] The surface resistivity of the insulating portion of the present invention is preferably 1×10⁻⁶. 9 Ω / □ or higher, more preferably 1×10 10 Ω / □ or higher, further preferably 1×10 11 Ω / □ or higher. By keeping the surface resistivity of the insulating portion within the above-mentioned range, the conductive laminate of the present invention can maintain higher insulation on the insulating portion side surface. Furthermore, the higher the surface resistivity of the insulating portion, the better, but it can typically be set to 1×10⁻⁶. 18 Ω / □ or less, 1×10 16 Ω / □ or less, 1×10 14 Ω / □ or more, 1×10 12 Below Ω / □.

[0115] The surface resistivity of the insulation refers to the value measured according to JIS-K6911. It can be measured using a resistivity meter (Advantest digital ultra-high resistance / micro current meter R8340, TR42 box) by applying a voltage of 500V to the black adhesive layer.

[0116] The insulating portion of the present invention is obtained by coating a black ink layer, in which black pigment is dispersed in an adhesive resin, onto the surface of a resin film serving as an insulating resin layer. The coating method can be any known and conventional coating method, and is not particularly limited thereto, but gravure coating is most preferred.

[0117] In the case where the insulating part of the present invention also has a matte layer on top of the black ink layer, the matte layer can be formed by coating the surface of the black ink layer with a surface treatment agent containing a matte agent (a light-reducing agent) in which microparticles such as silica are dispersed in a resin adhesive.

[0118] (Conductive laminate)

[0119] The total thickness of the conductive laminate of the present invention is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. Furthermore, the aforementioned total thickness is preferably 40 μm or less, more preferably 38 μm or less, and even more preferably 36 μm or less. More specifically, the total thickness of the conductive laminate of the present invention is preferably 20 μm or more and 40 μm or less, more preferably 25 μm or more and 38 μm or less, and even more preferably 30 μm or more and 36 μm or less. By making the total thickness of the conductive laminate within the above-mentioned range, a small total thickness and thin profile can be achieved, and a balance can be struck between conductivity, electromagnetic wave shielding, surface insulation, and blackness.

[0120] The conductive laminate of the present invention has the aforementioned layer structure. The surface of the conductive laminate located on the first main surface side of the conductive layer (i.e., the insulating portion side surface of the conductive laminate) displays given values ​​for lightness L*, chromaticity a*, and chromaticity b* as defined by the CIE L*a*b* color system. This suppresses the color of the conductive layer, resulting in excellent color concentration and hue on the insulating portion side surface of the conductive laminate, enabling the presentation of a high-quality black. Therefore, the conductive laminate of the present invention is thin and effectively satisfies conductivity, insulation, and electromagnetic shielding properties, thereby exhibiting excellent surface blackness, particularly black designability.

[0121] The lightness L* of the conductive laminate of the present invention, located on the first main surface side of the conductive layer, as defined by the CIE L*a*b* color system, is only required to be 20 or more, preferably 21 or more, 21.5 or more, 22 or more, or 22.5 or more. Furthermore, the lightness L* is only required to be 27 or less, preferably 25 or less, 24 or less, or 23 or less. More specifically, the lightness L* is only required to be 20 or more and 27 or less, preferably 21 or more and 25 or less, more preferably 21.5 or more and 24 or less, and even more preferably 22 or more and 23 or less. By ensuring that the lightness L* measured from the insulating portion side surface is within the above-mentioned range, the conductive laminate of the present invention can exhibit excellent blackness and design characteristics, and when used with black components, it can create a sense of unity with the blackness of the black components.

[0122] The chromaticity a* of the conductive laminate of the present invention, located on the first main surface side of the conductive layer, as defined by the CIE L*a*b* color system, is only required to be -2 or higher, preferably -1.5 or higher, -1 or higher, -0.5 or higher, or 0 or higher. Furthermore, the chromaticity a* is only required to be 2 or lower, preferably 1.5 or lower, 1 or lower, or 0.5 or lower. More specifically, the chromaticity a* is only required to be -2 or higher and 2 or lower, preferably -1 or higher and 1 or lower, and more preferably -0.5 or higher and 0.5 or lower. By ensuring that the chromaticity a* measured from the insulating portion side surface is within the aforementioned range, the conductive laminate of the present invention exhibits excellent black design characteristics as a conductive laminate, and when used with black components, it can create a sense of unity with the black appearance of the black components.

[0123] The chromaticity b* of the conductive laminate of the present invention, as defined by the CIE L*a*b* color system, on the surface of the conductive laminate located on the first main surface side of the conductive layer, only needs to be -2 or higher, preferably -1.5 or higher or -1 or higher. Alternatively, the chromaticity b* only needs to be 2 or lower, preferably 1.5 or lower, 1 or lower, 0.5 or lower, or 0 or lower. More specifically, the chromaticity b* only needs to be -2 or higher and 2 or lower, preferably -2 or higher and 0 or lower, -1.5 or higher and 0.5 or lower, -1.5 or higher and 0 or lower, or -1 or higher and 0 or lower. By ensuring that the chromaticity b* measured from the insulating portion side surface is within the aforementioned range, the conductive laminate of the present invention exhibits excellent black design characteristics as a conductive laminate, and when used with black components, it can create a sense of unity with the black appearance of the black components.

[0124] The lightness L* of the conductive laminate of the present invention located on the first main surface side of the conductive layer, as defined by the CIE L*a*b* color system, is only required to be 20 or more and 27 or less, the chromaticity a* is only required to be -2 or more and 2 or less, and the chromaticity b* is only required to be -2 or more and 2 or less. However, preferably, the lightness L* is 21 or more and 25 or less, the chromaticity a* is -1 or more and 1 or less, and the chromaticity b* is -1.5 or more and 0.5 or less. More preferably, the lightness L* is 21.5 or more and 24 or less, the chromaticity a* is -0.5 or more and 0.5 or less, and the chromaticity b* is -1 or more and 0 or less.

[0125] The CIE color values ​​(L*, a*, b*) of the conductive laminate of the present invention can be measured according to JIS Z8722. Specifically, the values ​​are measured from the insulating side surface of the conductive laminate using a SPECTROPHOTOMETER CM-5 manufactured by KONICA MINOLTA, according to the measurement standard JIS Z 8722 with a C spectrum of 2°.

[0126] Furthermore, the 60° gloss value of the conductive laminate of the present invention on the surface of the conductive laminate located on the first main surface side of the conductive layer is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and even more preferably 1 or more and 3 or less. By ensuring that the 60° gloss value measured from the insulating portion side surface of the conductive laminate of the present invention is within the aforementioned range, the glossiness is suppressed. As a conductive laminate, it exhibits excellent matte finish and design appeal. When used with black components, it can suppress noticeable glossiness and create a sense of unity with the blackness of the black components.

[0127] The 60° gloss value is the gloss level measured relative to the insulating side surface of the conductive laminate at a set angle of 60° according to JIS Z 8741. Measurements can be performed using commercially available measuring devices (e.g., the BYK Cat No. 4563 micro-TRI gloss meter).

[0128] Furthermore, the conductive laminate of the present invention, by having the above-described layer structure, is thin while exhibiting high insulation on the surface of the conductive laminate located on the first main surface side of the conductive layer (i.e., the insulating portion side surface), and on the other hand, exhibiting high conductivity on the surface of the conductive laminate located on the second main surface side of the conductive layer (i.e., the conductive layer side surface).

[0129] The surface resistivity of the conductive laminate of the present invention, located on the first main surface side of the conductive layer (i.e., the insulating portion side surface), is preferably 1×10⁻⁶. 8Ω / □ or higher, preferably 1×10 9 Ω / □ or higher, more preferably 1×10 10 Ω / □ or higher, further preferably 1×10 11 Ω / □ or higher. The conductive laminate of the present invention, by having the surface resistivity of the insulating portion side surface within the above-mentioned range, can exhibit higher insulation performance on the insulating portion side surface. Furthermore, a higher surface resistivity on the insulating portion side surface of the conductive laminate is more preferable, but it can generally be set to 1×10⁻⁶. 18 Ω / □ or less, 1×10 16 Ω / □ or less, 1×10 14 Ω / □ or less, 1×10 12 Below Ω / □.

[0130] Furthermore, the surface resistivity of the conductive laminate of the present invention on the surface of the conductive laminate located on the second main surface side of the conductive layer (i.e., the conductive layer side surface) is preferably 10 mΩ / □ or less, more preferably 1 mΩ / □ or less, and even more preferably 0.6 mΩ / □ or less. By keeping the surface resistivity of the conductive layer side surface within the above-mentioned range, the conductive laminate of the present invention can exhibit higher conductivity on the conductive layer side surface. Moreover, a lower surface resistivity on the conductive layer side surface of the conductive laminate is more preferable, but it can generally be set to 0.001 mΩ / □ or more.

[0131] The surface resistivity of the insulating side surface and the conductive layer side surface of the conductive laminate refers to the value measured according to JIS-K6911. It can be measured using a resistivity meter (Loresta MCP-T600 manufactured by Mitsubishi Chemical Corporation) by touching the probes of the four terminals on the insulating side surface or the conductive layer side surface of the conductive laminate.

[0132] (Manufacturing method of conductive laminate)

[0133] The method for manufacturing the conductive laminate of the present invention is not particularly limited. However, the manufacturing method comprising the steps of preparing black ink and black adhesive, forming an insulating portion by coating black ink on one side of an insulating resin layer to form an insulating portion having a black ink layer and an insulating resin layer, forming a black adhesive layer by coating the black adhesive on the side of the insulating portion opposite to the black ink layer to form a black adhesive layer, and forming a conductive layer by bonding a metal foil serving as a conductive layer onto the black adhesive layer, is preferred because it suppresses wrinkle formation and produces a conductive laminate with excellent productivity.

[0134] In the process of forming the insulating part, there is no particular limitation on the method of coating the insulating resin layer with black ink, as long as the thickness of the dried black ink layer is the desired size. For example, gravure coating can be used.

[0135] In addition, in the black adhesive layer formation process, there are no particular limitations on the method of applying the black adhesive, as long as the thickness of the dried black adhesive layer is the desired size. For example, known methods such as microgravure coating, die coating, and lip coating can be used.

[0136] (Applications of conductive laminates)

[0137] The conductive laminate of the present invention is thin and exhibits excellent conductivity, electromagnetic wave shielding, insulation, and surface blackness. Therefore, by providing a conductive adhesive layer on the second main surface of the conductive layer, either in a monomer or as described later, it can be widely applied to applications requiring these properties. It can be used for shielding or grounding applications in thin mobile devices, etc.

[0138] II. Conductive laminated tape

[0139] The conductive laminate tape of the present invention has a conductive laminate as described in the item “I. Conductive laminate” above and a conductive adhesive layer, wherein the conductive adhesive layer is disposed on the second main surface of the conductive layer constituting the conductive laminate.

[0140] The conductive laminated tape according to the present invention has a small total thickness and is thin, and can achieve a balance of various properties such as conductivity, electromagnetic wave shielding, surface insulation and blackness.

[0141] (Conductive laminate)

[0142] Regarding the conductive laminate of the present invention, since the details are the same as those described in the item “I. Conductive laminate” above, the description is omitted here.

[0143] (Conductive adhesive layer)

[0144] The conductive adhesive layer of the present invention comprises adhesive components and conductive fillers.

[0145] Nickel powder, copper powder, silver powder, gold powder, conductive carbon black, metal-plated glass, or resin powder can be used as conductive fillers. Among them, nickel powder is preferred because of its superior conductivity relative to the conductive layer of the conductive laminate, i.e., the metal foil, especially relative to copper foil and stainless steel foil.

[0146] The content of conductive filler in the conductive adhesive layer can be set to an amount that achieves the desired conductivity, and is not particularly limited. However, in the total amount (100% by mass) of the conductive adhesive layer, it is preferably in the range of 0.1% to 80% by mass, more preferably in the range of 0.5% to 40% by mass, and most preferably in the range of 0.8% to 10% by mass. This is because when the content of conductive filler is within the above range, it is easy to balance conductivity and adhesion even in a thin film.

[0147] There are no particular limitations on the adhesive components constituting the conductive adhesive layer. For example, suitable selections can be made from known adhesives such as acrylic adhesives, rubber adhesives, silicone adhesives, polyurethane adhesives, polyester adhesives, styrene-diene block copolymer adhesives, vinyl alkyl ether adhesives, polyamide adhesives, fluorinated adhesives, creep-modified adhesives, and radiation-cured adhesives. The adhesive components can be used alone or in combination of two or more.

[0148] Among these, acrylic adhesives, in particular, are preferred as adhesive components due to their high bonding reliability. Acrylic adhesives use (meth)acrylic polymers as the adhesive component or main agent, and may also include appropriate additives such as crosslinking agents, tackifiers, softeners, plasticizers, fillers, anti-aging agents, and colorants, depending on the requirements. (Meth)acrylic polymers are polymers with alkyl (meth)acrylates as the main monomer component, and are prepared by using monomers capable of copolymerizing with (meth)alkyl esters (copolymeric monomers), depending on the requirements.

[0149] As an acrylic copolymer, acrylic copolymers with (meth)acrylate monomers having 1 to 14 carbon atoms as the main monomer component are preferably used. Examples of (meth)acrylate monomers having 1 to 14 carbon atoms include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, isononyl methacrylate, cyclohexyl methacrylate, and 2-ethylhexyl methacrylate. One or more of these monomers can be used. Among these, (meth)acrylates with alkyl groups having 4 to 12 carbon atoms are preferred, and (meth)acrylates having a straight-chain or branched structure having 4 to 9 carbon atoms are more preferred. n-butyl acrylate and 2-ethylhexyl acrylate are preferred, and they can be used individually or in combination.

[0150] The content of (meth)acrylate with 1 to 14 carbon atoms in the acrylic copolymer is preferably 80% to 98.5% by mass of the monomer components constituting the acrylic copolymer, more preferably 90% to 98.5% by mass.

[0151] Furthermore, acrylic copolymers preferably copolymerize highly polar vinyl monomers. Examples of highly polar vinyl monomers include vinyl monomers with carboxyl groups, vinyl monomers with hydroxyl groups, and vinyl monomers with amide groups. One or more of these can be used. Among them, monomers containing carboxyl groups are preferred because they make it easier to adjust the adhesive properties of the adhesive to a suitable range.

[0152] As a vinyl monomer with a carboxyl group, acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, ethylene oxide modified succinic acid acrylate, etc. can be used, among which acrylic acid is preferred as a copolymer component.

[0153] When using vinyl monomers with carboxyl groups, their content is preferably 0.2% to 15% by mass of the monomer component constituting the acrylic copolymer, more preferably 0.4% to 10% by mass, and even more preferably 0.5% to 6% by mass. By including them within this range, the adhesive properties of the adhesive can be easily adjusted to an appropriate range.

[0154] As monomers containing hydroxyl groups, for example, hydroxyl-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate can be used.

[0155] In addition, examples of monomers with amide groups include N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, and N,N-dimethylacrylamide.

[0156] Other highly polar vinyl monomers include vinyl acetate, ethylene oxide-modified succinic acid acrylate, sulfonic acid monomers such as 2-acrylamide-2-methylpropanesulfonic acid, and terminal alkoxy-modified (meth)acrylates such as 2-methoxyethyl acrylate and 2-phenoxyethyl acrylate.

[0157] Regarding the content of highly polar vinyl monomers, the total amount is preferably 0.2% to 15% by mass of the monomer components constituting the acrylic copolymer, more preferably 0.4% to 10% by mass, and even more preferably 0.5% to 6% by mass. By including them within this range, the adhesive properties of the adhesive can be easily adjusted to an appropriate range.

[0158] The weight-average molecular weight (Mw) of the (meth)acrylic polymer is preferably 500,000 or more, 600,000 or more, or 700,000 or more. Furthermore, the weight-average molecular weight (Mw) of the (meth)acrylic polymer is preferably 2,000,000 or less, 1,800,000 or less, 1,600,000 or less, 1,200,000 or less, or 1,000,000 or less. By setting the weight-average molecular weight (Mw) of the (meth)acrylic polymer within the above range, the conductive adhesive layer can have good initial adhesion to the conductive layer of the conductive laminate. More specifically, the weight-average molecular weight (Mw) of the (meth)acrylic polymer is preferably in the range of 500,000 to 1,200,000, and more preferably in the range of 500,000 to 1,000,000.

[0159] (Meth)acrylic acid polymers can be prepared using conventional polymerization methods such as solution polymerization, emulsion polymerization, and ultraviolet irradiation polymerization.

[0160] To improve adhesion, a tackifying resin can be added to the conductive adhesive layer. Examples of tackifying resins include: rosin-based resins such as rosin and rosin ester compounds; terpene-based resins such as diterpene polymers and α-pinene-phenol copolymers; aliphatic (C5) and aromatic (C9) petroleum resins; styrene-based resins; phenolic resins; xylene resins; and methacrylic resins. Among these, rosin-based resins are preferred for thinness and improved adhesion, and polymerized rosin-based resins are more preferred. In addition to rosin-based resins, styrene-based resins may also be incorporated.

[0161] Furthermore, to improve initial adhesion, it is preferable to use a tackifying resin that is liquid at room temperature. Examples of tackifying resins that are liquid at room temperature include, for example, liquid resins of the aforementioned tackifying resins, processing oils, polyester plasticizers, and low molecular weight liquid rubbers such as polybutene. Terpene phenolic resins are particularly preferred. Commercially available products include YP-90L manufactured by Yasuhara Chemical Co., Ltd.

[0162] The amount of tackifying resin added is preferably in the range of 10 to 70 parts by weight relative to 100 parts by weight of the acrylic copolymer. More preferably, it is in the range of 20 to 60 parts by weight. By adding the tackifying resin within the above range, the adhesive strength can be improved.

[0163] The gel fraction of the conductive adhesive layer is not particularly limited, but it is preferred because sufficient adhesion is easily exhibited even in thin layers when it is in the range of 10 to 60% by mass, more preferably 20 to 50% by mass, and even more preferably 25 to 45% by mass.

[0164] For the gel fraction of the conductive adhesive layer, the cured conductive adhesive layer is immersed in toluene, and the mass of the remaining insoluble components after drying is measured after 24 hours. The result is expressed as a percentage of the original mass.

[0165] Gel fraction (mass%) = [(mass of conductive adhesive layer after toluene impregnation) / (mass of conductive adhesive layer before toluene impregnation)] × 100

[0166] The energy storage modulus of the conductive adhesive layer at 25°C is preferably 1×10⁻⁶. 4 Above and 5×10 5 Pa or less, more preferably 2×10 Pa 4 Above and 1×10 5 Pa or less. This is because, by ensuring that the storage modulus of the conductive adhesive layer at 25°C is within the aforementioned range, even for thin-film conductive adhesive layers, a high degree of balance between adhesion and processability can be easily achieved. Furthermore, the storage modulus of the conductive adhesive layer at 25°C is a value measured using the same method and conditions as the measurement method for the storage modulus of the black adhesive layer at 25°C described above.

[0167] The aforementioned conductive adhesive layer can be a single-layer structure or a multi-layer structure in which conductive adhesive layers are respectively provided on both sides of the conductive substrate.

[0168] Examples of conductive substrates used when the conductive adhesive layer has a multi-layer structure include metal foil substrates and substrates for which wet-process polyester nonwoven fabric substrates have been plated. Examples of metal foil materials include gold, silver, copper, aluminum, nickel, iron, tin, or alloys of these metals. Furthermore, examples of substrates for which wet-process polyester nonwoven fabric substrates have been plated include substrates using electroless metal plating. Examples of plating metals include copper, nickel, silver, platinum, and aluminum; copper or nickel is preferred from the viewpoint of conductivity and cost. The thickness of the conductive substrate is not particularly limited, but can be, for example, 1 μm or more to 50 μm or less.

[0169] The thickness of the conductive adhesive layer can be set to achieve both conductivity and adhesive size, preferably 2 μm or more and 60 μm or less, and more preferably 3 μm or more and 10 μm or less. By setting the thickness of the conductive adhesive layer within the above range, the total thickness of the conductive laminate of the present invention can be reduced, and the conductivity can be further improved.

[0170] In addition, when the conductive adhesive layer has a multilayer structure, the overall thickness of the multilayer structure is preferably 3 μm or more and 60 μm or less, and more preferably 5 μm or more and 10 μm or less.

[0171] The aforementioned conductive adhesive layer is disposed on the second main surface of the conductive layer of the conductive laminate. For example... Figure 3 As illustrated, the conductive adhesive layer 11 can be disposed over the entire area of ​​the second main surface of the conductive layer 1 of the conductive laminate 10, such as... Figure 4 As illustrated, the conductive adhesive layer 11 can be patterned on the second main surface of the conductive layer 1 of the conductive laminate 10. In the latter case, an insulating adhesive layer 12 can also be provided in the areas on the second main surface of the conductive layer 1 where the conductive adhesive layer 11 is not provided; that is, the conductive adhesive layer 11 and the insulating adhesive layer 12 can be alternately patterned on the second main surface of the conductive layer 10. The alternating patterned arrangement of the conductive adhesive layer and the insulating adhesive layer is preferred because it improves adhesion.

[0172] When the conductive adhesive layer and the insulating adhesive layer are arranged alternately in a pattern on the second main surface of the conductive layer, the insulating adhesive layer may be the same as the conductive adhesive layer except that it does not contain the conductive filler of the conductive adhesive layer.

[0173] (Arbitrary structure)

[0174] The conductive laminate of the present invention includes at least the aforementioned conductive laminate and conductive adhesive layer in its structure, but may also include other structures. For example, a release layer may be provided on the side of the conductive adhesive layer opposite to the conductive laminate. This is because providing a release layer protects the conductive laminate.

[0175] As a release layer, any known release layer can be appropriately selected. Resin films that have undergone mold release treatment exhibit excellent smoothness and are therefore preferred. Among these, polyester films are preferred from the viewpoint of excellent heat resistance.

[0176] To impart easy peeling, the surface of the release layer is preferably treated with a peeling process. Specifically, the surface of the release layer preferably has a peeling treatment layer. This peeling treatment layer can be formed using a common release agent used in the release layer of double-sided adhesive tapes. Examples of such release agents include silicone-based, fluorine-based, and long-chain alkyl-based release agents. The release treatment layer can be formed by lamination or coating.

[0177] The peel force of the release layer can be adjusted appropriately according to the application method, but the peel force relative to the conductive laminate can be 0.01 N / 20 mm to 2 N / 20 mm, preferably 0.05 N / 20 mm to 0.15 N / 20 mm. This is because deformation of the conductive laminate is easily suppressed when peeling off the release layer. The peel force can be measured by peeling a 50 μm thick PET film as the release layer from the exposed surface of the conductive adhesive layer of the conductive laminate at a speed of 0.3 m / min to 10 m / min in a 180° direction.

[0178] (Conductive laminated strips)

[0179] The total thickness of the conductive laminated tape of the present invention is preferably 22 μm or more and 100 μm or less, more preferably 25 μm or more and 50 μm or less, and even more preferably 30 μm or more and 45 μm or less. By setting the total thickness of the conductive laminated tape within the above-mentioned range, the total thickness is small and the tape is thin, and it is possible to achieve a balance between conductivity, electromagnetic wave shielding, surface insulation, and blackness. Furthermore, the total thickness of the conductive adhesive tape referred to in this specification does not include the thickness of the release layer.

[0180] The lightness L*, chromaticity a*, and chromaticity b* of the conductive laminate tape of the present invention, measured from the surface of the conductive laminate side and defined by the CIE L*a*b* color system, are preferably within the range of lightness L*, chromaticity a*, and chromaticity b* as defined by the CIE L*a*b* color system, as described in the above-described item "I. Conductive Laminate".

[0181] Furthermore, the 60° gloss value of the conductive laminate tape of the present invention, measured from the surface of the conductive laminate, is preferably within the range of the 60° gloss value measured from the insulating portion side surface of the conductive laminate as described in the item “I. Conductive Laminate” above.

[0182] The CIE color values ​​(L*, a*, b*) and 60° gloss values ​​of the conductive laminate of the present invention are measured under the same methods and conditions as those used for measuring the CIE color values ​​(L*, a*, b*) and 60° gloss values ​​of the conductive laminate described in the above-mentioned item "I. Conductive Laminate".

[0183] The shielding rate of the conductive laminate tape of the present invention, measured from the surface of the conductive laminate, is preferably within the range of the shielding rate measured from the insulating portion side surface of the conductive laminate as described in item "I. Conductive Laminate" above. The shielding rate of the conductive laminate tape is a value measured under the same method and conditions as the measurement method for the shielding rate measured from the insulating portion side surface of the conductive laminate as described in item "I. Conductive Laminate" above.

[0184] The surface resistivity of the conductive laminate tape of the present invention, measured from the surface of the conductive laminate, is preferably within the range of the surface resistivity measured from the insulating portion side surface of the conductive laminate as described in the item “I. Conductive Laminate” above.

[0185] Furthermore, the surface resistivity of the conductive laminate tape of the present invention, measured from the conductive adhesive side surface, is preferably 10 mΩ / □ or less, more preferably 1 mΩ / □ or less, and even more preferably 0.6 mΩ / □ or less. In addition, the lower the surface resistivity of the conductive laminate tape measured from the conductive adhesive side surface, the more preferred it is, but it is generally set to 0.001 mΩ / □ or more.

[0186] In addition, the surface resistivity of the conductive laminate side surface and the conductive adhesive layer side surface of the conductive laminate tape refers to the value measured according to JIS-K6911, which can be measured using a resistivity meter (Loresta MCP-T600 manufactured by Mitsubishi Chemical) by contacting the probes of the 4 terminals on the conductive laminate side surface or the conductive adhesive layer side surface of the conductive laminate tape.

[0187] (Method for manufacturing conductive laminated tape)

[0188] The manufacturing method of the conductive adhesive sheet of the present invention is not particularly limited. The conductive adhesive sheet of the present invention can be manufactured, for example, using a manufacturing method comprising the steps of preparing the conductive laminate described in item "I. Conductive laminate", preparing a conductive adhesive comprising conductive filler and adhesive components, and applying the conductive adhesive to the second main surface of the conductive layer of the conductive laminate in such a manner that the thickness after drying is of a desired size to form a conductive adhesive layer.

[0189] Furthermore, the conductive adhesive sheet of the present invention can be manufactured, for example, using a manufacturing method comprising the steps of preparing the conductive laminate described in the item “I. Conductive Laminate” above, preparing a conductive adhesive comprising conductive filler and adhesive components, applying the conductive adhesive to both sides of a conductive substrate in such a manner that the thickness after drying is of a desired size to form a conductive double-sided adhesive tape, and bonding the second main surface of the conductive layer of the above-mentioned conductive laminate to an adhesive layer of the conductive double-sided adhesive tape.

[0190] The conductive adhesive sheet of the present invention can be used in the same way as those described in the above-mentioned item "I. Conductive laminate".

[0191] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative and may have a structure that is substantially the same as the technical concept described in the scope of this disclosure, and achieve the same effect. Regardless of the structure, all are included within the technical scope of this disclosure.

[0192]

Example

[0193] The following provides a detailed description of the embodiments and comparative examples.

[0194] (Polyurethane resin solution A)

[0195] In four flasks equipped with a stirrer, thermometer, reflux cooler, and nitrogen inlet tube, 192.9 parts by mass of a polyester polyol with a number average molecular weight (Mn) of 2000 (obtained by reacting adipic acid / terephthalic acid ratio of 50 / 50) with 3-methyl-1,5-pentanediol, 15.8 parts by mass of 1,4-butanediol, and 77.9 parts by mass of isophorone diisocyanate were added. The mixture was reacted at 90°C for 5 hours under a nitrogen atmosphere. Next, 11.0 parts by mass of isophorone diamine, 2.4 parts by mass of di-n-butylamine, and 700 parts by mass of methyl ethyl ketone were added, and the mixture was reacted at 50°C for 4 hours with a stirrer to obtain a polyurethane resin solution A with a resin solids concentration of 30.0% by mass, Gardner viscosity U (25°C), amine value of 0, and a weight average molecular weight of 30000.

[0196] (Black ink)

[0197] The prepared polyurethane resin solution A was supplemented with 55 parts by weight (NV 30%), 10 parts by weight of (1-{4-[(4,5,6,7-tetrachloro-3-oxoisoindoline-1-ylidene)amino]phenylazo}-2-hydroxy-N-(4'-methoxy-2'-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide) as an organic black pigment (near-infrared reflective pigment "CHROMOFINE BLACK A1103" manufactured by Daihatsu Seika Co., Ltd. (CAS No.: 103621-96-1)), 5 parts by weight of inorganic filler ("Sylophobic 704" manufactured by Fuji Silysia Co., Ltd., silane coupling treatment: average particle size 3.5 μm based on Coulter counting method), and 2 parts by weight of spherical silicone resin beads (Momentive Performance). Materials Corporation's "Tospearl2000B": 2 parts by weight of polyethylene micropowder wax (BASF's "Luwax AF29 Micropowder"), 1 part by weight of dispersant (Lubrizol's "solsperse 24000GR"), 13 parts by weight of methyl ethyl ketone, 9 parts by weight of ethyl acetate, 5 parts by weight of isopropanol, and 5 parts by weight of propylene glycol monomethyl ether were wet-dispersed in a sand mill for approximately 1 hour to obtain a mixture. To prepare a black ink, 5 parts by weight of hexamethylene diisocyanate-type isocyanurate (Sumijour N3300 polyisocyanate curing agent manufactured by Sumitomo Chemical Bayer Polyurethane Co., Ltd.) and 40 parts by weight of diluent (DIC Graphics' "NH-NT DC solvent") were added to this mixture.

[0198] (Black ink coating A (insulating part A))

[0199] A polyester film (Toray Industries F53 Lumirror#2.0, thickness: 2.0 μm) was used as the insulating resin layer. Black ink was applied to one side of the polyester film using gravure coating so that the thickness after drying was 1.0 μm. The film was then dried at 100°C for 1 minute to obtain a black ink layer.

[0200] Next, on the black ink layer, OS-M suede OP varnish manufactured by Dainippon Seika Co., Ltd. was used as a matte agent to achieve a matte ink layer (matte layer) thickness of 0.5 μm through gravure coating. The coating was dried at 100°C for 1 minute and aged at 40°C for 2 days. This resulted in a black ink coating film A (insulating part A) with a black ink layer formed on one side of the polyester film (insulating resin layer) and a matte ink layer (matte layer) formed on top of the black ink layer. The total thickness of the black ink coating film A was 3.5 μm. Furthermore, the thickness of the black ink layer was measured by cutting the black ink coating film A with a razor and magnifying the cross-section using a microscope at 2500x magnification.

[0201] (Black ink coating B (insulating part B))

[0202] In addition to using a polyimide film (Toray & DuPont "Kapton 20EN", thickness: 5.0 μm) as the insulating resin layer instead of a polyester film (Toray Industries "F53 Lumirror#2.0", thickness: 2.0 μm), a black ink coating film B (insulating part B) was obtained in the same manner as black ink coating film A, in which a black ink layer was formed on one side of the polyimide film (insulating resin layer) and a matte ink layer (masking layer) was formed on the black ink layer. The total thickness of black ink coating film B is 6.5 μm.

[0203] (Preparation of transparent adhesive A)

[0204] In a reaction vessel equipped with a cooling pipe, a stirrer, a thermometer, and a dropping funnel, 97.98 parts by weight of n-butyl acrylate, 2 parts by weight of acrylic acid, 0.02 parts by weight of 4-hydroxybutyl acrylate, and 0.2 parts by weight of azobisisobutyronitrile (azobisisobutyronitrile) as a polymerization initiator were added to an ethyl acetate solution. Solution polymerization was carried out in the solution at 80°C for 8 hours to obtain an acrylic polymer A with a weight average molecular weight of 900,000.

[0205] Next, 5 parts by mass of polymeric rosin ester (trade name "D-135" manufactured by Arakawa Chemical Co., Ltd.), 20 parts by mass of disproportionated rosin ester (trade name "KE-100" manufactured by Arakawa Chemical Co., Ltd.), and 25 parts by mass of petroleum resin (trade name "FTR6100") were added to 100 parts by mass of acrylic polymer A, and ethyl acetate was further added to prepare acrylic adhesive solution A with a solid content of 40% by mass.

[0206] To 100 parts by weight of acrylic adhesive solution A (40% by weight solids), 0.8 parts by weight of isocyanate-based crosslinking agent (trade name "NC40", manufactured by DIC, 40% by weight solids) were added and mixed by stirring to achieve homogeneity, thereby preparing transparent adhesive A. Transparent adhesive A has a gel fraction of 20% by weight and a storage modulus of 9 × 10⁻⁶ at 25°C. 4 Pa.

[0207] (Preparation of black adhesive B)

[0208] To 100 parts by weight of the above acrylic adhesive solution A (40% by weight solids), 10 parts by weight of a black colorant (DICTON Black AR8555, manufactured by DIC, carbon black content: 45% (solids percentage), resin solids concentration: 49%) was added and mixed thoroughly with a mixer. Then, 1.2 parts by weight of an isocyanate-based crosslinking agent (trade name "NC40", manufactured by DIC) was added and the mixture was stirred until homogeneous, thereby preparing black adhesive B. Black adhesive B has a gel fraction of 20% by weight and a storage modulus of 9 × 10⁻⁶ at 25°C. 4 Pa.

[0209] (Preparation of black adhesive C)

[0210] Black adhesive C was prepared by mixing 15 parts by weight of a polyester adhesive (DIC Graphics' "DickDry LX-703VL" for dry lamination, 62% solids), 1 part by weight of an isocyanate curing agent (DIC Graphics' "KR-90" curing agent, 90% solids), and 1 part by weight of a black colorant (DIC's "DICTON BlackAR8555", carbon black content: 45% (solids ratio), resin solids concentration: 49%), and stirring to achieve a homogeneous mixture. The gel fraction of black adhesive C was 90% by weight, and its storage modulus at 25°C was 2 × 10⁻⁶. 5 Pa.

[0211] In addition, the gel fraction of various adhesives is determined by immersing the various adhesives in toluene, measuring the mass of the remaining insoluble components after drying after 24 hours, and expressing it as a percentage relative to the original mass.

[0212] Gel fraction (mass%) = [(mass of adhesive after toluene impregnation) / (mass of adhesive before toluene impregnation)] × 100

[0213] (Preparation of conductive adhesive A)

[0214] In a reaction vessel equipped with a cooling pipe, a stirrer, a thermometer, and a dropping funnel, 75.0 parts by weight of n-butyl acrylate, 19.0 parts by weight of 2-ethylhexyl acrylate, 3.9 parts by weight of vinyl acetate, 2.0 parts by weight of acrylic acid, 0.1 parts by weight of 2-hydroxyethyl acrylate, and 0.1 parts by weight of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator were dissolved in 100 parts by weight of ethyl acetate. After nitrogen replacement, the mixture was polymerized at 80°C for 12 hours to obtain acrylic polymer B with a weight average molecular weight of 600,000.

[0215] Next, in 100 parts by mass of the solid component of acrylic polymer B, 10 parts by mass of polymeric pentaerythritol rosin (manufactured by Arakawa Chemical Industry Co., Ltd., "Pencel D-135", softening point 135°C) and 10 parts by mass of disproportionated rosin glycerol ester (manufactured by Arakawa Chemical Industry Co., Ltd., "Super ester A-100", softening point 100°C) were combined, and ethyl acetate was used to adjust the concentration of the solid component of the acrylic polymer to 40% by mass, thereby obtaining acrylic adhesive solution B.

[0216] Conductive adhesive A is prepared by mixing 100 parts by weight of acrylic adhesive solution B (solid content concentration 40% by weight), 0.4 parts by weight of nickel powder (Ni255T bead-shaped conductive particles manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., d50: 26.0 μm), 2 parts by weight of isocyanate crosslinking agent (Barnock NC40 manufactured by DIC Co., Ltd., solid content 40% by weight), and 70 parts by weight of ethyl acetate as diluent using a dispersing mixer for 10 minutes.

[0217] (Preparation of insulating adhesive A)

[0218] Insulating adhesive A is prepared by mixing 100 parts by weight of acrylic adhesive solution B (solid content concentration 40% by weight), 2 parts by weight of isocyanate crosslinking agent (Barnock NC40 manufactured by DIC Corporation, solid content 40% by weight) and 70 parts by weight of ethyl acetate as diluent using a dispersion mixer for 10 minutes.

[0219] (Manufacturing of conductive adhesive tape A)

[0220] Conductive adhesive A is applied to a release film A (manufactured by Nippa Corporation under the trade name "PET38×1K0") to achieve a thickness of 5 μm after drying. The film is then dried at 100°C for 2 minutes to form a conductive adhesive layer A, thereby obtaining a conductive adhesive tape A.

[0221] (Manufacturing of Insulating Adhesive Tape A)

[0222] Insulating adhesive A is applied to a release film A (manufactured by Nippa Corporation under the trade name "PET38×1K0") to achieve a thickness of 5 μm after drying. The film is then dried at 100°C for 2 minutes to form an insulating adhesive layer A, thereby obtaining an insulating adhesive tape A.

[0223] (Preparation of Adhesive C)

[0224] In a reaction vessel equipped with a stirrer, reflux cooler, thermometer, dropping funnel, and nitrogen inlet, 60 parts by mass of n-butyl acrylate, 35.95 parts by mass of 2-ethylhexyl acrylate, 4.0 parts by mass of acrylic acid, 0.05 parts by mass of 4-hydroxybutyl acrylate, and 0.2 parts by mass of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator were dissolved in a mixed solvent of 50 parts by mass of ethyl acetate and 20 parts by mass of n-hexane, and polymerized at 70°C for 8 hours to obtain acrylic copolymer C with a weight average molecular weight of 700,000.

[0225] Next, relative to 100 parts by mass of the solid component of acrylic copolymer C, 20 parts by mass of polymeric rosin ester resin (manufactured by Arakawa Chemical Industry Co., Ltd., "D-125") and 10 parts by mass of disproportionated rosin ester (manufactured by Arakawa Chemical Industry Co., Ltd., "A100") were added, and the concentration of the solid component was adjusted to 45% by mass using ethyl acetate, thereby obtaining acrylic adhesive solution C.

[0226] Next, 100 parts by weight of acrylic adhesive solution C (45 parts by weight of solids) and 1.7 parts by weight of isocyanate crosslinking agent (Barnock NC-40 manufactured by DIC Corporation, 40% by weight of solids, ethyl acetate solution) were mixed and stirred for 10 minutes using a dispersing mixer to obtain acrylic adhesive C.

[0227] (Example 1)

[0228] On the polyester film surface of the black ink coating A, black adhesive B is gravure-coated to a thickness of 1.5 μm after drying. After drying at 70°C for 2 minutes to form black adhesive layer B, it is laminated to the matte side of a 30 μm thick electrolytic copper foil (manufactured by Fukuda Metal Foil Powder Industry "CF-PLFA-30"). Further aging at 40°C for 2 days yields a conductive laminate. The glossy side of the electrolytic copper foil has an Rz of 0.72 μm and an Ra of 0.11 μm. The matte side of the electrolytic copper foil has an Rz of 1.4 μm and an Ra of 0.23 μm.

[0229] (Example 2)

[0230] Except that a 33μm thick electrolytic copper foil (Fukuda Metal Foil Powder Industry Co., Ltd. "CF-PLFA-33") was used instead of a 30μm thick electrolytic copper foil, a conductive laminate was obtained in the same manner as in Example 1. The glossy surface of the electrolytic copper foil had an Rz of 0.78μm and an Ra of 0.12μm. Furthermore, the matte surface of the electrolytic copper foil had an Rz of 1.5μm and an Ra of 0.25μm.

[0231] (Example 3)

[0232] The conductive laminate was obtained in the same manner as in Example 1, except that black ink coating B was used instead of black ink coating A.

[0233] (Example 4)

[0234] Except that a black adhesive layer C with a thickness of 1.5 μm after drying is formed by using black adhesive C instead of black adhesive B, a conductive laminate is obtained in the same manner as in Example 1.

[0235] (Example 5)

[0236] Except that a 30μm thick rolled copper foil ("TCu-O-30" manufactured by Fukuda Metal Foil Powder Industry) was used instead of the 30μm thick electrolytic copper foil "CF-PLFA-30", a conductive laminate was obtained in the same manner as in Example 1. The surface roughness of the electrolytic copper foil was not internal or external, with Rz of 0.6μm and Ra of 0.1μm.

[0237] (Example 6)

[0238] The conductive adhesive layer A of the conductive adhesive tape A is bonded to the electrolytic copper foil side of the conductive laminate of Example 1, and then aged at 40°C for 2 days to obtain the conductive laminate tape. The release film A of the conductive adhesive tape A is peeled off during evaluation. In addition, the release film A is not included in the total thickness of the conductive laminate tape.

[0239] (Example 7)

[0240] On the electrolytic copper foil surface of the conductive laminate of Example 1, conductive adhesive tape A and insulating adhesive tape A are alternately bonded with a width of 5 mm, and then aged at 40°C for 2 days to obtain a conductive laminate. The release film A of conductive adhesive tape A and insulating adhesive tape A is peeled off during evaluation. In addition, the release film A is not included in the total thickness of the conductive laminate.

[0241] (Comparative Example 1)

[0242] The acrylic adhesive C was applied to the release liner (manufactured by Nippa Corporation, “PET38×1A3”) using a roller coater to achieve a thickness of 50 μm after drying. The liner was dried in an 80°C dryer for 3 minutes to form a transparent adhesive layer C, which was then cured at 40°C for 48 hours.

[0243] Next, the adhesive layer described above is bonded to one side of an electrolytic copper foil substrate with a thickness of 35 μm. Then, an adhesive tape with a total thickness of 10 μm (manufactured by DIC Corporation, "IL-10BMF", having a laminated structure of a black coloring layer (thickness: 1.5 μm) / polyethylene terephthalate film (thickness: 4.5 μm) / transparent adhesive layer (thickness: 4 μm) (" / " indicates the laminated interface) is bonded to the other side of the electrolytic copper foil substrate, thereby creating a conductive laminated tape.

[0244] (Comparative Example 2)

[0245] On one side of a 5μm thick PET film (manufactured by Teijin DuPont Film Co., Ltd., "Mylar"), at 3g / m 2 (Conversion of Dry Coating Amount) The coating used an isocyanate-based curing agent ("Coronate L" manufactured by Nippon Polyurethane Kogyo Co., Ltd.) and a polyester resin ("UE3220" manufactured by UNITIKA Co., Ltd.), and a 7μm thick flexible aluminum foil (1030N-0 material from Nippon Foil Co., Ltd.) was laminated on the other side of the PET film to form the substrate.

[0246] After peeling off the PET film, an acrylic adhesive containing 10% by mass of carbon black is applied to a dry thickness of 5 μm and dried to form a conductive black adhesive layer. The previously prepared substrate is then laminated onto this conductive black adhesive layer.

[0247] Next, insulating black ink (ink in which aniline black is dispersed into polyester resin) is coated onto the substrate with a dry thickness of 3 μm and dried to form a black ink layer, thereby obtaining a conductive laminate.

[0248] (Comparative Example 3)

[0249] The conductive laminate was obtained in the same manner as in Example 1, except that transparent adhesive A was used instead of black adhesive B and a transparent adhesive layer with a thickness of 1.5 μm after drying was formed.

[0250] (Comparative Example 4)

[0251] On the glossy surface of an electrolytic copper foil (Fukuda Metal Foil Powder Industry Co., Ltd. "CF-T8G-DK-35") with a thickness of 35 μm, black ink A was gravure-coated to a thickness of 4.5 μm and dried at 100°C for 1 minute to form a black ink layer A. Next, on the black ink layer, OS-M suede OP varnish manufactured by Daihatsu Seika Co., Ltd. was used for gravure coating to make the thickness of the matte ink layer (masked layer) 0.5 μm, and dried at 100°C for 1 minute. Thus, a conductive laminate with a layer structure of matte ink layer (masked layer) / black ink layer / electrolytic copper foil ( / indicates the laminate interface) was obtained. The glossy surface of the electrolytic copper foil has an Rz of 1.4 μm and an Ra of 0.18 μm. In addition, the matte surface of the electrolytic copper foil has an Rz of 10.2 μm and an Ra of 1.6 μm.

[0252] Furthermore, the ten-point average surface roughness Rz and arithmetic average roughness Ra of the conductive layer used in the embodiments and comparative examples were measured at any three points on the surface of the conductive layer using a HANDYSURF+ manufactured by Tokyo Seijinsha, in accordance with JIS B0601, and the average value of the three points obtained from the measurements was obtained.

[0253] [evaluate]

[0254] The performance of the conductive laminates and conductive laminates of the Examples and Comparative Examples were evaluated using the following measurement methods.

[0255] (thickness)

[0256] Using a thickness gauge (NIKON Corporation DIGIMICRO MFC-101), the total thickness of the conductive laminate portion of the conductive laminates of Examples 1-5 and Comparative Examples 3-4, and the conductive laminate strips of Examples 6-7 and Comparative Examples 1-2, was measured. Additionally, the total thickness of the adhesive layer, including the adhesive layer disposed on the second main surface of the conductive layer, was also measured for the conductive laminate strips of Examples 6-7 and Comparative Examples 1-2.

[0257] (thinness)

[0258] The thickness of the conductive laminate portion of the conductive laminates of Examples 1-5 and Comparative Examples 3-4, and the conductive laminates of Examples 6-7 and Comparative Examples 1-2, was evaluated according to the following evaluation criteria.

[0259] 〇: Below 40μm

[0260] ×: Exceeding 40μm

[0261] (L*, a*, b*)

[0262] Using a spectrophotometer (KONICA MINOLTA SPECTROPHOTOMETER CM-5), and in accordance with the measurement standard JIS Z 8722 with a C spectrum of 2°, the CIE color values ​​(L*, a*, b*) were measured on the insulating side surface of the conductive laminates of Examples 1-5 and Comparative Examples 3-4, and the conductive laminate tapes of Examples 6-7 and Comparative Examples 1-2.

[0263] (60° gloss value)

[0264] According to JIS Z 8741, at a set angle of 60°, the gloss value (gloss Gu) was measured on the surface of the insulating portion of the conductive laminates of Examples 1-5 and Comparative Examples 3-4, and the conductive laminate tapes of Examples 6-7 and Comparative Examples 1-2, using a MINOLTA Multi-Gloss 268 manufactured by KONICA MINOLTA.

[0265] (Opacity of the black adhesive layer)

[0266] The opacity of the black adhesive layer of the conductive laminates of Examples 1-5 and Comparative Examples 3-4, and the conductive laminate tapes of Examples 6-7 and Comparative Examples 1-2 was measured using the following method. Black adhesives B and C used in the examples were coated onto one side of a release film (manufactured by Nippa Corporation, trade name "PET38×1K0") to a thickness of 1.5 μm after drying. The coatings were dried at 70°C for 2 minutes to form a black adhesive layer, resulting in a black adhesive tape. Next, the black adhesive tape was attached to the white and black sides of opacity test paper (manufactured by Nippon Test Panel Industry Co., Ltd.). The release film was peeled off, and the Y value, representing luminance, of the black adhesive layer attached to the white and black sides was measured using the color measurement method specified in JIS-Z-8722. Using a colorimeter "CM-3500d" (manufactured by Minolta Corporation), the standard light C in a 2-degree field of view was measured. The measured Y value was substituted into the following formula to measure the opacity.

[0267] Opacity (%) = (Y value of black adhesive layer attached to black side / Y value of black adhesive layer attached to white side) × 100%

[0268] (Insulation)

[0269] Using a resistivity meter (Loresta MCP-T600 manufactured by Mitsubishi Chemical Corporation), the surface resistivity of the insulating portion side surface (the surface opposite to the conductive layer side surface) of the conductive laminates of Examples 1-5 and Comparative Examples 3-4, and the insulating portion side surface (the surface opposite to the conductive adhesive layer side surface) of the conductive laminate tapes of Examples 6-7 and Comparative Examples 1-2, was measured by contacting the probes of the four terminals. Evaluation was conducted according to the following evaluation criteria.

[0270] 〇:9.9×10 7 Surface resistivity above Ω / □ (overload)

[0271] ×: less than 9.9 × 10 7 Surface resistivity of Ω / □

[0272] (Conductivity)

[0273] Using a resistivity meter (LorestaMCP-T600, Mitsubishi Chemical Corporation), the surface resistivity of the conductive layer side surface of the conductive laminates in Examples 1-5 and Comparative Examples 3-4 was measured by contacting the probes of the four terminals. Additionally, the surface resistivity of the conductive adhesive layer side surface was measured in the conductive laminates in Examples 6-7 and Comparative Examples 1-2. Evaluations were conducted according to the following evaluation criteria.

[0274] ◎: 0.6mΩ / □ or less

[0275] 〇: More than 0.6mΩ / □, less than 10mΩ / □

[0276] ×:More than 10mΩ / □

[0277] (Electromagnetic wave shielding)

[0278] Test pieces 25, each 20 mm wide and 40 mm long, were cut from the conductive laminates of Examples 1-5 and Comparative Examples 3-4, and the conductive laminates of Examples 6-7 and Comparative Examples 1-2. Samples were made by sealing the center of an aluminum plate 27 with a thickness of 0.5 mm × 20 cm × 20 cm, leaving a 5 mm × 20 mm slit 26 in the center. Figure 5 The conductive laminate test piece 25 was placed on an aluminum plate, and the conductive laminate test piece 25 was attached to the aluminum plate 27. Next, the above-mentioned sample was placed in a magnetic field shielding box 28 (manufactured by Shield Room Corporation) according to the Kansai Electronics Industry Promotion Center (KEC) method. A spectrum analyzer 29 (Anritsu MS2661C) was placed in the shielding box, and the shielding characteristics against electromagnetic waves at a frequency of 3 GHz were evaluated according to the following evaluation criteria. Figure 6 ).

[0279] ◎: 45db or more

[0280] ○: Above 40dB and below 45dB

[0281] ×: Less than 40dB

[0282] (Adhesion)

[0283] A 25 μm thick PET film (Lumirror S10#25 manufactured by Toray Industries, Inc.) was bonded to conductive adhesive A on conductive adhesive tape A to form a sheet with a structure of release film A / conductive adhesive layer A / PET film. Next, the sheet was cut into 20 mm wide × 100 mm long pieces. Release film A was peeled off, and conductive adhesive layer A was bonded to the conductive layer side (copper foil) of the conductive laminates of Examples 1-5 and Comparative Examples 3-4. After one reciprocating press with a 2 kg roller, the sheet was placed at 23°C and 50% RH for 1 hour, and the adhesive force was measured when peeled at a speed of 300 mm / min in the 180° direction. Evaluation was performed according to the following evaluation criteria.

[0284] ◎: 3N / 20mm or more

[0285] 〇: 1N / 20mm or more and less than 3N / 20mm

[0286] ×: Less than 1N / 20mm

[0287] (Adhesive strength of conductive laminate adhesive tape)

[0288] Samples of conductive laminates from Examples 1-5 and Comparative Examples 3 and 4, with conductive adhesive tape A bonded to the conductive layer, were placed at 23°C and 50% RH for one day, then cut into 25mm wide x 100mm long pieces, attached to an SUS plate, subjected to one reciprocating pressure with a 2kg roller, and placed at 23°C and 50% RH for one hour. The adhesive force was measured when peeled at a speed of 300mm / min in the 180° direction. Similarly, the conductive laminate tapes from Examples 6 and 7 were directly cut into 25mm wide x 100mm long pieces, attached to an SUS plate, subjected to one reciprocating pressure with a 2kg roller, and placed at 23°C and 50% RH for one hour. The adhesive force was measured when peeled at a speed of 300mm / min in the 180° direction. Evaluation was conducted according to the following evaluation criteria.

[0289] ◎: 8N / 25mm and above

[0290] 〇: 4N / 25mm or more and less than 8N / 25mm

[0291] ×: Less than 4N / 25mm

[0292] The results are presented in Tables 1-4.

[0293] Table 1

[0294]

[0295] Table 2

[0296]

[0297] Table 3

[0298]

[0299] Table 4

[0300]

[0301] As can be seen from Tables 1-4, the conductive laminates of Examples 1-5 and the conductive laminates of Examples 6-7 have a layer structure in which an insulating part having a black ink layer and an insulating resin layer, a black adhesive layer, and a metal foil as a conductive layer are stacked in sequence. As a result, the total thickness is small and the laminate is thin. It can also exhibit high conductivity, high electromagnetic wave shielding and high surface insulation. Moreover, by having the above-mentioned laminate structure, the lightness L*, chromaticity a* and b* of the insulating part side surface of the conductive laminate can be set to a given range, which can improve the surface blackness, especially the black design.

[0302] (Label Explanation)

[0303] 1…Conductive layer (metal foil), 2…Black adhesive layer, 3…Insulating part, 4…Insulating resin layer, 5…Black ink layer, 10…Conductive laminate, 11…Conductive adhesive layer, 12…Insulating adhesive layer, 20…Conductive laminate tape.

Claims

1. A conductive layered body, comprising: a conductive layer having first and second opposing main faces; a black adhesive layer provided on the first main face of the conductive layer; and an insulating portion provided on the black adhesive layer, the conductive layer being a metal foil, the insulating portion having an insulating resin layer and a black ink layer, a 60° gloss value of a surface of the conductive layered body on the first main face side of the conductive layer being 1 or more and 5 or less.

2. The conductive layered body according to claim 1, wherein the insulating resin layer and the black ink layer are sequentially layered from the black adhesive layer side.

3. The conductive layered body according to claim 1 or 2, wherein the metal foil is a copper foil.

4. The conductive layered body according to claim 3, wherein the copper foil is an electrolytic copper foil.

5. The conductive layered body according to claim 1 or 2, wherein a ten-point average surface roughness (Rz) of the conductive layer is 2.0 μm or less.

6. The conductive layered body according to claim 1 or 2, wherein a thickness of the black ink layer is 1 μm or more and 3 μm or less.

7. The conductive layered body according to claim 1 or 2, wherein a thickness of the insulating resin layer is 1 μm or more and 5 μm or less. a surface of the conductive layered body on the first main surface side of the conductive layer has a colorimetric value of L* of 20 or more and 27 or less, a colorimetric value of a* of -2 or more and 2 or less, and a colorimetric value of b* of -2 or more and 2 or less, according to CIE 1976 colorimetric system a lightness of 20 or more and 27 or less a chroma of -2 or more and 2 or less a chroma of -2 or more and 2 or less a chroma of -2 or more and 2 or less 8. The conductive layered body according to claim 1 or 2, wherein a hiding rate of the black adhesive layer is 20% or more.

9. The conductive layered body according to claim 1 or 2, wherein a total thickness of the conductive layered body is 20 μm or more and 40 μm or less.

10. A conductive layered tape, comprising the conductive layered body according to any one of claims 1 to 9, and a conductive adhesive layer, the conductive adhesive layer being provided on the second main face of the conductive layer constituting the conductive layered body.

11. The conductive layered tape according to claim 10, wherein the conductive adhesive layer is provided in a pattern on the second main face of the conductive layer, and an insulating adhesive layer is provided in a region on the second main face where the conductive adhesive layer is not provided. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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