JP7689832B2 - Anti-corrosion adhesive tape - Google Patents

Description

The present invention relates to an anticorrosive adhesive tape, and more specifically, to an anticorrosive adhesive tape for preventing corrosion of iron or iron-containing alloys, such as steel materials.

Anti-corrosion paints containing large amounts of zinc are widely used to protect steel and other iron or iron-containing alloys from corrosion. Zinc is a metal with a lower potential than iron and is known to have high corrosion protection because of its sacrificial anti-corrosion properties. However, corrosion protection using paint requires a drying process after application, which takes time, and reduces work efficiency when performing localized repairs in civil engineering and construction applications such as bridges. Furthermore, corrosion protection using paint is prone to uneven work.

In view of the above situation, efforts have been made in the past to improve workability by imparting sacrificial corrosion protection to adhesive tapes and the like. For example, Patent Document 1 discloses a corrosion protection member having a conductive adhesive layer containing a metal with a lower potential than iron and a conductive material other than that metal. The conductive adhesive layer of this corrosion protection member contains a conductive material other than a metal with a lower potential than iron in addition to a metal with a lower potential than iron, so that it is not necessary to contain a large amount of a metal with a lower potential than iron in order to exhibit good sacrificial corrosion protection. This allows the corrosion protection member to have good adhesiveness.

JP 2019-127606 A

Although the adhesion of the anticorrosion member in Patent Document 1 is excellent, the adhesion of the anticorrosion member described in Patent Document 1 may be insufficient depending on the object of corrosion protection. For this reason, an anticorrosion member with even better adhesion is desired.
Therefore, an object of the present invention is to provide an anticorrosive pressure-sensitive adhesive tape that has excellent corrosion prevention properties while also having good adhesive properties.

As a result of extensive research, the inventors have discovered that the above-mentioned problems can be solved by using a metal having a lower potential than iron as a base material and incorporating an anisotropic conductive material into the adhesive layer to impart conductivity to the adhesive layer, and have completed the present invention, which is described below.
That is, the present invention provides the following [1] to [9].
[1] A corrosion-resistant adhesive tape comprising a metal layer and an adhesive layer provided on at least one surface of the metal layer, the metal layer being a layer of a metal having a lower electric potential than iron, and the adhesive layer containing an anisotropic conductive material.
[2] The pressure-sensitive adhesive tape according to the above-mentioned [1], wherein the pressure-sensitive adhesive layer has a total light transmittance X per 1 μm of thickness of 99.85% or less.
[3] The anticorrosive adhesive tape according to the above [1] or [2], wherein the anisotropic conductive material has an aspect ratio of 2 or more.
[4] The anticorrosive adhesive tape according to any one of the above [1] to [3], wherein the anisotropic conductive material is a carbon-based material.
[5] The anticorrosive adhesive tape according to the above [4], wherein the carbon-based material is a carbon nanotube.
[6] The anticorrosive pressure-sensitive adhesive tape according to any one of the above [1] to [5], wherein the pressure-sensitive adhesive layer has a resistance value of 1×10 ⁸ to 1×10 ¹⁴ Ω.
[7] The anticorrosive adhesive tape according to any one of the above [1] to [6], wherein the thickness of the adhesive layer is 20 μm or more.
[8] The corrosion-preventive adhesive tape according to any one of the above [1] to [7], wherein the metal layer is zinc foil.
[9] The corrosion-preventive adhesive tape according to any one of the above [1] to [8], wherein the thickness of the metal layer is 2.5 μm or more.

The present invention provides an anticorrosive adhesive tape that combines excellent corrosion resistance and good adhesiveness.

FIG. 1 is a schematic diagram showing one example of the configuration of the anticorrosive pressure-sensitive adhesive tape of the present invention. FIG. 2 is a schematic diagram showing one example of the configuration of the anticorrosive pressure-sensitive adhesive tape of the present invention. FIG. 3 is a schematic diagram showing one example of the configuration of the anticorrosive pressure-sensitive adhesive tape of the present invention. FIG. 4 is a schematic diagram showing one example of the configuration of the anticorrosive pressure-sensitive adhesive tape of the present invention.

The anticorrosive adhesive tape of the present invention comprises a metal layer and an adhesive layer provided on at least one surface of the metal layer, the metal layer being a layer of a metal having a lower electric potential than iron, and the adhesive layer containing an anisotropic conductive material. This allows the anticorrosive adhesive tape of the present invention to exhibit excellent corrosion prevention properties with a small amount of conductive material blended, and as a result, good adhesion can be achieved. The anticorrosive adhesive tape of the present invention will be described in detail below.

(metal layer)
The metal layer in the anticorrosive pressure-sensitive adhesive tape of the present invention is a layer of a metal having a lower electric potential than iron, and thus, by attaching the anticorrosive pressure-sensitive adhesive tape of the present invention to an adherend, the metal layer corrodes instead of the adherend, and the adherend can be protected from corrosion by so-called sacrificial corrosion protection.
The metal layer is not particularly limited, but is preferably a metal foil. Examples of metals with a lower potential than iron include cadmium, chromium, zinc, manganese, and aluminum. Among these metals, zinc and aluminum are preferred from the viewpoint of corrosion resistance, and zinc is more preferred. Therefore, it is more preferred that the metal layer is a zinc foil.

The adherend used is one containing iron or an alloy containing iron. Specific examples of alloys containing iron include alloy steels such as nickel-chrome steel, nickel-chrome-molybdenum steel, chrome steel, chrome-molybdenum steel, and manganese steel, as well as various steel materials such as carbon steel. The adherend is not particularly limited, but examples include steel materials used in various civil engineering and construction applications, vehicle applications such as automobiles, railways, aircraft, and ships, and various electrical appliances, as well as other metal parts, with steel materials used in civil engineering and construction applications being preferred.

<Thickness of Metal Layer>
The thickness of the metal layer is preferably 2.5 μm or more. When the thickness of the metal layer is 2.5 μm or more, the metal layer can sufficiently supply electrons due to ionization of the metal in the metal layer to the adherend, and the sufficient corrosion resistance of the anticorrosive adhesive tape can be maintained. From the viewpoint of improving the corrosion resistance of the anticorrosive adhesive tape, the thickness of the metal layer is more preferably 5 μm or more. In addition, from the viewpoint of ensuring the flexibility of the anticorrosive adhesive tape and improving the handling property of the anticorrosive adhesive tape, the thickness of the metal layer is preferably 200 μm or less, more preferably 100 μm or less.

(Adhesive Layer)
The pressure-sensitive adhesive layer contains an anisotropic conductive material. This allows the metal in the metal layer to be ionized and the electrons generated therefrom to be efficiently supplied to the adherend even if the pressure-sensitive adhesive layer contains a small amount of conductive material. As a result, the anticorrosive pressure-sensitive adhesive tape of the present invention has excellent anticorrosive properties and good adhesive properties.

<Anisotropic conductive materials>
An anisotropic conductive material is a conductive material having anisotropy in shape. Examples of anisotropic conductive materials include fibrous conductive materials and scale-like conductive materials. An anisotropic conductive material has a high aspect ratio, for example, an aspect ratio of 2 or more, preferably an aspect ratio of 5 or more, more preferably an aspect ratio of 10 or more, and even more preferably an aspect ratio of 500 or more. By making the aspect ratio 2 or more, even if the conductive material in the adhesive layer is small, it is possible to efficiently supply electrons generated by ionization of the metal in the metal layer to the adherend, making it easier to achieve both excellent corrosion resistance and good adhesion. The upper limit of the aspect ratio is not particularly limited.
Specifically, the aspect ratio is the ratio of the length in the long axis direction to the length in the short axis direction of the anisotropic conductive material, which means the fiber length/fiber diameter in the case of a fibrous conductive material, and means the length in the long axis direction/thickness in the case of a scaly conductive material. The lengths in the short axis direction and the long axis direction of the anisotropic conductive material may be measured, for example, in an image obtained by observation with an electron microscope or an optical microscope.
The anisotropic conductive material is preferably a fibrous conductive material, from the viewpoint that a small content of the material can effectively move electrons generated by ionization of the metal in the metal layer.

From the viewpoint of the anticorrosive properties and adhesiveness of the anticorrosive adhesive tape, the content of the anisotropic conductive material in the adhesive layer is preferably 0.001 to 4 parts by mass, more preferably 0.005 to 1 part by mass, and even more preferably 0.008 to 0.5 parts by mass, relative to 100 parts by mass of the adhesive. By keeping the content within the above range, it is possible to prevent the adhesive strength of the adhesive layer from being reduced by the anisotropic conductive material while ensuring high anticorrosive properties.
In addition, when the adhesive layer is formed from an acrylic adhesive described later, the content of the anisotropic conductive material is preferably 0.001 to 1 part by mass, more preferably 0.005 to 0.5 parts by mass, even more preferably 0.008 to 0.2 parts by mass, and even more preferably 0.01 to 0.1 parts by mass, relative to 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) described later. When the content of the anisotropic conductive material is equal to or greater than these lower limits, the sacrificial corrosion resistance is likely to be improved, and when the content of the anisotropic conductive material is equal to or less than these upper limits, the adhesive strength is likely to be improved.

When the anisotropic conductive material is a fibrous conductive material, the average fiber length is preferably 0.1 to 1000 μm, more preferably 10 to 500 μm. When the average fiber length is 0.1 μm or more, the anisotropic conductive material is in appropriate contact with each other inside the pressure-sensitive adhesive layer, and a conduction path for electrons generated by ionization of the metal in the metal layer is easily secured.
On the other hand, if the average fiber length is 1000 μm or less, the anisotropic conductive material becomes easier to handle.
When the anisotropic conductive material is a fibrous conductive material, the average diameter is preferably 1 to 100 nm, more preferably 2 to 15 nm, and the aspect ratio (average fiber length/average diameter) of the fibrous conductive material is preferably 10 to 100,000, more preferably 500 to 30,000.
The average fiber length and average diameter can be calculated by observing the anisotropic conductive material under a microscope. More specifically, the fiber lengths and diameters of 50 arbitrary anisotropic conductive materials can be measured in an image obtained by observation under an electron microscope or optical microscope, and the average values (arithmetic mean values) can be used as the average fiber length and average diameter.

Examples of anisotropic conductive materials include carbon-based materials, metal-based materials, and metal oxide-based materials.
Examples of carbon-based materials include carbon fibers such as PAN (polyacrylonitrile)-based carbon fibers, rayon-based carbon fibers, phenol-based carbon fibers, and pitch-based carbon fibers, graphene, carbon nanotubes, carbon nanofibers, carbon nanocoils, and flake graphite.
When the metal-based material is a simple metal, it is preferable that the metal has a lower potential than iron. If a metal having a more noble potential than iron is used, electrons may flow from the iron to the metal-based material, which may hinder the movement of electrons from the metal layer to the iron.
Specific examples of the metallic material include flake aluminum and aluminum fibers.
Metal oxide materials include, for example, zinc oxide.
These conductive materials may be used alone or in combination of two or more.

Of these anisotropic conductive materials, from the viewpoint of improving the conductivity of the adhesive layer without impairing adhesion, carbon-based materials are preferred, and among these, fibrous carbon-based materials such as carbon nanotubes, carbon nanofibers, and carbon fibers are more preferred, with carbon nanotubes being even more preferred.
Carbon nanotubes are substances having a structure in which graphite sheets with a hexagonal mesh-like carbon atom arrangement are rolled into a cylindrical shape. A single-wall carbon nanotube is a single-layer roll, and a multi-wall carbon nanotube is a multi-layer roll. In the present invention, the type of carbon nanotube is not particularly limited, and may be any of single-wall carbon nanotubes, multi-wall carbon nanotubes, and mixtures containing these in any ratio. Carbon nanotubes manufactured by various methods such as arc discharge, laser evaporation, and chemical vapor deposition (CVD) can be used. The preferred ranges of the average length, average diameter, and aspect ratio of carbon nanotubes are the same as those of the average fiber length, average diameter, and aspect ratio described in the above-mentioned fibrous conductive material. The diameter of carbon nanotubes refers to the outer diameter in the case of single-wall carbon nanotubes, and refers to the outer diameter of the tube located at the outermost position in the case of multi-wall carbon nanotubes.

The adhesive layer may contain, in addition to the anisotropic conductive material, a conductive material that does not have an anisotropic shape (hereinafter referred to as a non-anisotropic conductive material) to the extent that the effect of the present invention is not impaired. A non-anisotropic conductive material is a conductive material with a low aspect ratio, for example, a conductive material with an aspect ratio of less than 2. However, from the viewpoint of increasing the adhesiveness while maintaining the excellent corrosion resistance of the anticorrosive adhesive tape, it is preferable that the adhesive layer does not contain a non-anisotropic conductive material.

The particle size of the non-anisotropic conductive material is preferably 1 to 200 μm. By setting the particle size of the non-anisotropic conductive material to 200 μm or less, it becomes easier to disperse the non-anisotropic conductive material in the adhesive layer while suppressing a decrease in the adhesiveness of the adhesive layer. By setting the particle size of the non-anisotropic conductive material to 1 μm or more, it becomes easier to improve the conductivity of the adhesive layer by the non-anisotropic conductive material. The above particle size is more preferably 5 to 100 μm. In this specification, the particle size means the average particle size measured by a laser diffraction method.

The non-anisotropic conductive material may be, for example, one or more selected from carbon-based materials, metal-based materials, metal oxide-based materials, ionic polymers, and conductive polymers.
Examples of carbon-based materials include carbon black, graphite, and acetylene black. Examples of metal-based materials include metals with a more noble potential than iron, such as gold, silver, copper, nickel, or alloys containing these metals, and metals with a less noble potential than iron, such as iron, cadmium, chromium, zinc, manganese, and aluminum. If a less noble metal is used as the metal-based material, sacrificial corrosion protection is also possible with a non-anisotropic conductive material. Examples of metal oxide materials include indium tin oxide (ITO), antimony trioxide (ATO), fluorine-doped tin oxide (FTO), and zinc oxide. Examples of conductive polymers include polyacetylene, polypyrrole, PEDOT (polyethylenedioxythiophene), PEDOT/PSS (a composite of polyethylenedioxythiophene and polystyrene sulfonic acid), polythiophene, polyaniline, poly(p-phenylene), polyfluorene, polycarbazole, polysilane, or derivatives thereof. Examples of the ionic polymer include sodium polyacrylate and potassium polyacrylate.
The anisotropic conductive material may be used alone or in combination of two or more kinds.

<Adhesive>
The pressure-sensitive adhesive layer is preferably formed by blending an anisotropic conductive material into a pressure-sensitive adhesive. In this specification, the components in the pressure-sensitive adhesive layer other than the anisotropic conductive material and the non-anisotropic conductive material are defined as the pressure-sensitive adhesive.
Examples of adhesives used in the adhesive layer include acrylic adhesives, rubber adhesives, urethane adhesives, and silicone adhesives. These adhesives may be used alone or in combination. Among these, it is preferable to use acrylic adhesives. The use of acrylic adhesives makes it easier to improve the adhesive performance of the anticorrosive adhesive tape.

Next, the adhesive used in the adhesive layer will be described in more detail.
<<Acrylic adhesive>>
The acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing an acrylic polymer obtained by polymerizing a polymerizable monomer including a (meth)acrylic acid alkyl ester monomer (A).
In this specification, the term "(meth)acrylic acid alkyl ester" refers to a concept including both acrylic acid alkyl ester and methacrylic acid alkyl ester, and the same applies to other similar terms. Furthermore, the term "polymerizable monomer" refers to a concept including not only a compound having no repeating unit, but also a monomer itself having a repeating unit, such as the olefin polymer (C) described later, so long as it is a compound that can be copolymerized with the (meth)acrylic acid alkyl ester monomer (A).

[(Meth)acrylic acid alkyl ester monomer (A)]
The (meth)acrylic acid alkyl ester monomer (A) is an ester of (meth)acrylic acid and an aliphatic alcohol, and is preferably an alkyl ester derived from an aliphatic alcohol in which the carbon number of the alkyl group of the aliphatic alcohol is preferably 2 to 14, more preferably 4 to 10. When the carbon number of the alkyl group is within this range, the glass transition temperature (Tg) of the pressure-sensitive adhesive layer can be set to an appropriate temperature range, making it easier to adjust the adhesive properties of the pressure-sensitive adhesive layer.

Specific examples of the (meth)acrylic acid alkyl ester monomer (A) include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, and tetradecyl (meth)acrylate.
Among these, n-butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-octyl (meth)acrylate are preferred, and n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, or a combination thereof is more preferred.
The (meth)acrylic acid alkyl ester monomers may be used alone or in combination of two or more kinds.

The constituent unit derived from the (meth)acrylic acid alkyl ester monomer (A) constitutes the main component of the adhesive, and its content is generally 30 mass% or more, preferably 40 mass% or more, more preferably 45 wt% or more based on the total amount of the adhesive. In this way, by increasing the content of the (meth)acrylic acid alkyl ester monomer (A), it is possible to impart the desired adhesive strength to the adhesive.
The content of the constituent unit derived from the (meth)acrylic acid alkyl ester monomer (A) in the pressure-sensitive adhesive is substantially the same as the content of the (meth)acrylic acid alkyl ester monomer (A) in the pressure-sensitive adhesive composition described below, and can be expressed by replacing the content of the (meth)acrylic acid alkyl ester monomer (A). The same applies to components other than the component (A), such as the components (B) and (C) described below.

[Polar Group-Containing Vinyl Monomer (B)]
The polymerizable monomer preferably contains a polar group-containing vinyl monomer (B) in addition to the (meth)acrylic acid alkyl ester monomer (A). The polar group-containing vinyl monomer (B) has a polar group and a vinyl group. By using the polar group-containing monomer (B) in the pressure-sensitive adhesive layer, the adhesive properties of the pressure-sensitive adhesive layer can be easily adjusted.
Examples of the polar group-containing vinyl monomer (B) include carboxylic acid vinyl esters such as vinyl acetate, carboxylic acids containing a vinyl group such as (meth)acrylic acid and itaconic acid, and their anhydrides, vinyl monomers having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone-modified (meth)acrylate, polyoxyethylene (meth)acrylate, and polyoxypropylene (meth)acrylate, and nitrogen-containing vinyl monomers such as (meth)acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllaurolactam, (meth)acryloylmorpholine, (meth)acrylamide, dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and dimethylaminomethyl(meth)acrylate.
Among these, (meth)acrylic acid, itaconic acid, and other vinyl group-containing carboxylic acids and their anhydrides are preferred, (meth)acrylic acid is more preferred, and acrylic acid is even more preferred. These polar group-containing vinyl monomers (B) may be used alone or in combination of two or more.

When a polar group-containing vinyl monomer (B) is used, the content of the structural units derived from the polar group-containing vinyl monomer (B) in the adhesive is preferably 1 to 15 parts by mass, more preferably 2 to 12 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A). By setting the content of the polar group-containing vinyl monomer (B) within this range, it becomes easier to adjust the adhesive properties of the adhesive layer to an appropriate range.

[Olefin polymer (C)]
The polymerizable monomer preferably further contains an olefin polymer (C) having a polymerizable bond at the end. By using such an olefin polymer (C), the shear strength of the adhesive can be increased. The polymerizable bond means an unsaturated carbon-carbon bond capable of polymerizing with the polymerizable monomer, such as an unsaturated double bond, preferably a (meth)acryloyl group.
Examples of the olefin polymer (C) include polyolefins having a (meth)acryloyl group, such as polyolefins having a (meth)acryloyl group at only one end and polyolefins having (meth)acryloyl groups at both ends. Note that the polyolefin is a polymer of an aliphatic hydrocarbon compound having a double bond, such as ethylene, propylene, butane, butadiene, isoprene, or the like, or a hydrogenated product thereof.

Examples of polyolefins having a (meth)acryloyl group at only one end include polyethylene having a (meth)acryloyl group at one end, which is prepared by reacting polyethylene having an epoxy group at one end with (meth)acrylic acid. Other examples include polybutadiene having a (meth)acryloyl group at one end or a hydrogenated product thereof, and examples of commercially available products include "L-1253" manufactured by Kuraray Co., Ltd.

Examples of olefin polymers having (meth)acryloyl groups at both ends include polypropylene having (meth)acryloyl groups at both ends, which is prepared by reacting polypropylene having epoxy groups at both ends with (meth)acrylic acid. Examples of polybutadiene having (meth)acryloyl groups at both ends or hydrogenated products thereof include commercially available products such as "TEAI-1000", "EA-3000", and "TE-2000" manufactured by Nippon Soda Co., Ltd. and "BAC-45" manufactured by Osaka Organic Chemical Industry Ltd.
The olefin polymer (C) may be used alone or in combination of two or more kinds.

Of the above-mentioned olefin polymers (C), polyolefins having (meth)acryloyl groups at both ends or one end are preferred, and polybutadiene having (meth)acryloyl groups at both ends or one end or a hydrogenated product thereof is particularly preferred.
When a polyolefin having (meth)acryloyl groups at both ends is used as the olefin polymer (C), it becomes possible to polymerize an acrylic polymer in a network shape, which makes it easier to increase the cohesive strength of the pressure-sensitive adhesive and adjust the adhesive properties of the pressure-sensitive adhesive layer.
Furthermore, as the olefin polymer (C), it is preferable to use in combination an olefin polymer having a (meth)acryloyl group at one terminal and an olefin polymer having (meth)acryloyl groups at both terminals.

The number average molecular weight of the olefin polymer (C) is preferably 500 to 20000, more preferably 1000 to 10000. The number average molecular weight may be measured by gel permeation chromatography (GPC) and calculated using a calibration curve of standard polystyrene.
In addition, the content of the structural unit derived from the olefin polymer (C) in the pressure-sensitive adhesive is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 4 to 12 parts by mass, per 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A).

[Other monomers]
The polymerizable monomer may contain other monomers in addition to the above (A) to (C). Examples of the other monomers include styrene-based monomers and polyfunctional monomers. Examples of the styrene-based monomers include styrene, α-methylstyrene, o-methylstyrene, and p-methylstyrene.
The polyfunctional monomer may be a monomer having two or more vinyl groups, preferably a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups. The use of the polyfunctional monomer makes it possible to form a network structure in the acrylic polymer.
Specific examples of polyfunctional monomers include hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, proxilated trimethylolpropane triacrylate, proxilated glyceryl triacrylate, and neopentyl glycol adipate diacrylate.
When other monomers are used, the content of the structural units derived from the other monomers in the pressure-sensitive adhesive is 0.5 to 15 parts by mass, more preferably 1 to 7 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[Tackifier resin]
The acrylic adhesive may contain a tackifier resin from the viewpoint of improving adhesive strength. As the tackifier resin, a tackifier resin having low polymerization inhibition properties, such as hydrogenated terpene resin, hydrogenated rosin, disproportionated rosin resin, petroleum resin, etc., is preferable. Among these, hydrogenated tackifier resins are preferable because tackifier resins having many double bonds inhibit polymerization reactions, and hydrogenated petroleum resins are particularly preferable.
From the viewpoint of improving the cohesive strength and adhesive strength of the adhesive, the softening point of the tackifier resin may be about 95° C. or higher, but preferably includes one having a softening point of 120° C. or higher, and for example, one having a softening point of 95° C. or higher and lower than 120° C. may be used in combination with one having a softening point of 120° C. or higher and 150° C. or lower. The softening point may be measured by the ring and ball method specified in JIS K2207.
The content of the tackifier resin in the acrylic pressure-sensitive adhesive is preferably 5 to 40 parts by mass, more preferably 7 to 35 parts by mass, and even more preferably 10 to 25 parts by mass, relative to 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[Other ingredients]
The acrylic adhesive used in the present invention may contain, in addition to the above-mentioned components, various additives conventionally used in adhesives, such as fine particles other than metals having a lower electric potential than iron and other than the above-mentioned conductive materials, plasticizers, softeners, pigments, dyes, photopolymerization initiators, and flame retardants.

[Gel fraction]
The gel fraction of the acrylic adhesive is preferably 30 to 80% by mass. By setting the gel fraction within the above range, the cohesive strength of the adhesive is adjusted to an appropriate range, and adhesive properties such as adhesive strength are easily improved. From these viewpoints, the gel fraction is preferably 40 to 70% by mass, more preferably 45 to 65% by mass.
The gel fraction can be adjusted within the above range by, for example, appropriately adjusting the presence or absence of blending of an olefin polymer (C) having two or more (meth)acryloyl groups and a polyfunctional monomer, and the blending amount. The gel fraction can be calculated from the following formula (1). In order to set the gel fraction within the above range, it is preferable that the polymerizable monomer contains at least one of a polyfunctional monomer and an olefin polymer (C) having two or more (meth)acryloyl groups. Compounds having two or more functional groups, such as a polyfunctional monomer and an olefin polymer (C) having two or more (meth)acryloyl groups, are sometimes collectively referred to as crosslinking agents.
Gel fraction (mass%)=(B/A)×100 Formula (1)
A: Weight of adhesive B: Dry weight of insoluble portion of adhesive after immersing adhesive in tetrahydrofuran at 40° C. for 48 hours

<<Rubber-based adhesive>>
Next, the rubber-based adhesive used in the adhesive will be described. The rubber-based adhesive contains a rubber component and a tackifier resin, and it is preferable to use a styrene-isoprene block copolymer as the rubber component. The styrene-isoprene block copolymer has a diblock ratio of preferably 25 to 70% by mass, more preferably 30 to 65% by mass, and even more preferably 45 to 60% by weight. Here, the diblock refers to a diblock consisting of styrene and isoprene. The styrene-isoprene block copolymer exhibits sufficient adhesive strength when the diblock ratio is 25% or more, and the shear strength is easily increased when the diblock ratio is 70% or less by mass. In addition to the diblock, the styrene-isoprene block copolymer also contains one having three or more blocks, such as a triblock consisting of styrene, isoprene, and styrene blocks.

The amount of styrene in the styrene-isoprene block copolymer is not particularly limited, but is preferably 14 to 24% by mass, and more preferably 15 to 18% by mass. If the amount of styrene is 14% by mass or more, the adhesive will have high cohesiveness. If the amount is 24% by mass or less, the cohesive force will be of an appropriate magnitude, and appropriate adhesive performance will be easily exhibited.
The molecular weight of the styrene-isoprene block copolymer is not particularly limited, but is preferably a mass average molecular weight of 100,000 to 400,000, more preferably 150,000 to 250,000. The mass average molecular weight referred to here is a molecular weight measured in terms of polystyrene by a GPC (gel permeation chromatography) method.

The tackifier resin used in the rubber-based adhesive can be any of various types, but is preferably a petroleum-based resin, a terpene resin, or a coumarone resin. The tackifier resin may be used alone or in combination of two or more types, but it is preferable to use a petroleum-based resin in combination with at least one selected from a terpene resin and a coumarone resin. Such a combination of tackifier resins makes it easier to improve the adhesive strength.
Examples of the petroleum resin include aliphatic petroleum resin (C5 petroleum resin), alicyclic petroleum resin, aromatic petroleum resin, etc., and from the viewpoint of compatibility with the styrene-isoprene block copolymer, aliphatic petroleum resin is preferred. In addition, it is preferable to use a petroleum resin having a softening point of about 90 to 120°C.
The terpene resin to be used has a softening point of about 80 to 120° C., but from the viewpoint of ensuring adhesive strength, it is preferable that the softening point is less than 100° C. The coumarone resin to be used has a softening point of preferably 110 to 130° C., more preferably 115 to 125° C., in order to ensure cohesive strength.

The amount of the tackifier resin is preferably 60 to 250 parts by mass, more preferably 100 to 200 parts by mass, and even more preferably 110 to 180 parts by mass, per 100 parts by mass of the rubber component. By setting the amount of the tackifier resin within the above range, it is possible to improve the cohesive force and impart appropriate adhesive strength.
In addition, when a petroleum-based resin is used in combination with at least one selected from a terpene resin and a coumarone resin, the amount of the petroleum-based resin is preferably 50 to 200 parts by mass, more preferably 60 to 150 parts by mass, and more preferably 60 to 110 parts by mass, per 100 parts by mass of the rubber component. On the other hand, the amount of the terpene resin is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, per 100 parts by mass of the rubber component. Furthermore, the amount of the coumarone resin is preferably 10 to 60 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of the rubber component.
The rubber-based adhesive may contain the above-mentioned fine particles, like the acrylic-based adhesive, and may also contain a softener, an antioxidant, a filler, etc., as necessary.

<<Urethane-based adhesive>>
The urethane adhesive is not particularly limited, and examples thereof include urethane resins obtained by reacting at least a polyol with a polyisocyanate compound. Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone polyol, etc. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, etc. These urethane adhesives may be used alone or in combination of two or more.
In addition, the urethane adhesive may be a urethane resin obtained by reacting a polyurethane polyol with a polyfunctional isocyanate-based curing agent. The polyurethane polyol may be a reaction product of the above-mentioned polyol with a polyisocyanate compound, or a reaction product of a polyol with a polyisocyanate compound and a chain extender such as a diamine. The polyfunctional isocyanate-based curing agent may be any compound having two or more isocyanate groups, and may be any of the above-mentioned isocyanate compounds.
The urethane-based adhesive may contain, in addition to the urethane resin, the above-mentioned fine particles, similar to the acrylic-based adhesive, and the urethane-based adhesive may also contain a tackifier resin, a softener, an antioxidant, a filler, etc., as necessary.

<<Silicone-based adhesive>>
Examples of silicone-based adhesives include silicone-based adhesives of addition reaction type, peroxide curing type, or condensation reaction type. Among them, addition reaction type silicone-based adhesives are preferably used from the viewpoint of being curable at low temperature in a short time. The addition reaction type silicone-based adhesive is cured when the adhesive layer is formed. When the addition reaction type silicone-based adhesive is used as the silicone-based adhesive, the silicone-based adhesive may contain a catalyst such as a platinum catalyst.
The silicone-based adhesive may contain the above-mentioned fine particles, as in the case of the acrylic-based adhesive, and may also contain a crosslinking agent and various additives for controlling adhesive strength.

<Total Light Transmittance of Pressure-Sensitive Adhesive Layer>
The total light transmittance X per 1 μm of the thickness of the adhesive layer is preferably 99.85% or less. When the total light transmittance X is 99.85% or less, the anticorrosive properties of the anticorrosive adhesive tape are good, and it is easy to prevent corrosion of the adherend using the anticorrosive adhesive tape. From the viewpoint of improving the anticorrosive properties, the total light transmittance X is preferably 99.83% or less, more preferably 99.8% or less, and even more preferably 99.7% or less. In addition, when an acrylic adhesive is used, from the viewpoint of improving the curing properties of the entire adhesive layer, the total light transmittance X is preferably 97% or more, more preferably 98% or more. The total light transmittance X can be adjusted by the type and content of the anisotropic conductive material.

The total light transmittance X (%) per 1 μm of thickness can be calculated from the total light transmittance Y (%) and the thickness T (μm) of the pressure-sensitive adhesive layer according to the following formula.

The total light transmittance Y is a value measured in accordance with JIS K7361-1. The total light transmittance can be measured using a haze meter (e.g., Haze Meter NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd.) in an atmosphere of 23°C and humidity of 50%.

<Resistance Value of Pressure-Sensitive Adhesive Layer>
By containing the above-mentioned anisotropic conductive material, the pressure-sensitive adhesive layer can efficiently transfer electrons emitted when the metal in the metal layer is ionized to the adherend without lowering the resistance value so much. Specifically, the resistance value of the pressure-sensitive adhesive layer is, for example, 1×10 ⁸ Ω or more, and is preferably higher than 1×10 ⁸ Ω. When the resistance value of the pressure-sensitive adhesive layer is higher than 1×10 ⁸ Ω, the content of the anisotropic conductive material in the pressure-sensitive adhesive layer can be reduced, and the adhesiveness of the pressure-sensitive adhesive layer can be further improved. In addition, by using the anisotropic conductive material in the present invention, even if the resistance value is high, electrons can be efficiently transferred to the adherend, and sufficient corrosion resistance can be ensured.
The resistance value of the pressure-sensitive adhesive layer is preferably 1× ¹⁰ Ω or less. When the resistance value of the pressure-sensitive adhesive layer is 1× ¹⁰ Ω or less, the electrons released when the metal in the metal layer is ionized can be sufficiently transferred to the adherend, and the corrosion resistance of the anticorrosive pressure-sensitive adhesive tape can be improved. From this viewpoint, the resistance value is more preferably 1×10 ⁹ to 5×10 ¹³ Ω, and even more preferably 1×10 ¹⁰ to 2×10 ¹³ Ω or less. The resistance value of the pressure-sensitive adhesive layer can be measured by the method described in the Examples below.

<Thickness of Adhesive Layer>
The thickness of the adhesive layer is preferably 20 μm or more. When the thickness of the adhesive layer is 20 μm or more, the adhesive layer can exhibit appropriate adhesion and anticorrosion properties. From this viewpoint, the thickness of the adhesive layer is more preferably 50 μm or more, even more preferably 100 μm or more, even more preferably 150 μm or more, even more preferably 250 μm or more, and even more preferably 400 μm or more. The upper limit of the thickness of the adhesive layer is not particularly limited, but is, for example, 1 cm.

<Adhesive strength of adhesive layer>
The adhesive strength of the adhesive layer is preferably 10 N/25 mm or more, more preferably 20 N/25 mm or more, and even more preferably 30 N/25 mm or more. The upper limit of the adhesive strength of the adhesive layer is not particularly limited, but is, for example, 110 N/25 mm. The adhesive strength of the adhesive layer can be measured by the measurement method described in the Examples below.

The surface of the adhesive layer that will be the adhesive surface may be protected by attaching a release sheet. The release sheet used may be a substrate such as a resin film, at least one side of which has been treated for release with a silicone-based release agent or the like.

<Base material>
The anticorrosive adhesive tape may have a substrate in addition to the metal layer. The substrate may be provided on the side opposite to the side of the metal layer on which the adhesive layer is provided. The substrate may be attached to the metal layer via an adhesive layer made of an adhesive, a pressure sensitive adhesive, or the like. The adhesive layer may be an adhesive layer that does not contain a conductive material. With the above configuration, the adhesive layer containing the anisotropic conductive material is protected by the substrate, and the anticorrosive adhesive tape has better corrosion resistance.
Examples of the substrate include nonwoven fabric, paper such as Japanese paper, woven fabric made of natural fibers, synthetic fibers, etc., resin films made of polyester, polyolefin, soft polyvinyl chloride, hard polyvinyl chloride, acetate, etc., flat yarn cloth, etc. In addition, as the adhesive and pressure-sensitive adhesive used in the adhesive layer, known ones may be appropriately used.

(Method for manufacturing anticorrosive adhesive tape)
The adhesive layer can be formed by applying an adhesive composition comprising an adhesive component and a conductive material to a metal foil that constitutes the metal layer, and crosslinking, curing, etc., the adhesive composition as necessary.
The adhesive layer may be formed by applying the adhesive composition to a release sheet and crosslinking or curing the adhesive composition as necessary. In this case, after forming the adhesive layer on the surface of the release sheet, a metal layer may be further formed on the surface of the adhesive layer. The metal layer may be formed, for example, by laminating a metal foil formed by thinly forming a metal on the adhesive layer. The metal layer may be formed by coating the surface of the adhesive layer with a metal by a thin film forming method such as sputtering or vacuum deposition. The lamination of the metal foil or the coating of the metal on the adhesive layer may be performed after crosslinking and curing the adhesive composition, before crosslinking and curing, or while crosslinking and curing.
The pressure-sensitive adhesive composition may be used after being appropriately diluted with a solvent, etc. Hereinafter, a detailed description will be given of an example in which the above-mentioned acrylic pressure-sensitive adhesive is used as the pressure-sensitive adhesive.

When an acrylic adhesive is used, the adhesive layer can be obtained by irradiating light to an adhesive composition comprising a component constituting the adhesive, including the above-mentioned polymerizable monomer, and a conductive material, to polymerize the polymerizable monomer.
More specifically, first, a polymerizable monomer, an anisotropic conductive material, and optionally a nontropic conductive material, a tackifier resin, and other components are charged into a reaction vessel such as a glass vessel and mixed to obtain a pressure-sensitive adhesive composition.
Next, in order to remove dissolved oxygen in the adhesive composition, an inert gas such as nitrogen gas is generally supplied to purge the oxygen. Then, the adhesive composition is applied onto a release sheet or a metal layer. A protective release sheet may be further laminated onto the applied adhesive composition. Thereafter, the adhesive composition is irradiated with light such as ultraviolet light to polymerize the polymerizable monomer, thereby obtaining an adhesive layer.
In addition, after appropriately peeling off the protective release sheet, the adhesive layer formed on the release sheet may be further provided with a metal layer on the surface opposite to the surface on which the release sheet is provided, thereby providing a metal layer on the surface of the adhesive layer.
In addition, in the obtained anticorrosive pressure-sensitive adhesive tape, a substrate may be further attached onto the metal layer using an adhesive or pressure-sensitive adhesive.

The steps from application or impregnation of the pressure-sensitive adhesive composition to the step of irradiating with light are preferably carried out in an inert gas atmosphere or in a state where oxygen is blocked by a film or the like.
In the present production method, the pressure-sensitive adhesive composition obtained by mixing the components may be pre-polymerized before being applied to a release sheet, a metal layer, or the like, in order to increase the viscosity.

Examples of lamps that can be used when irradiating the pressure-sensitive adhesive composition with light include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps. Among these, chemical lamps are preferred. The light irradiation intensity when irradiating the pressure-sensitive adhesive composition with light varies depending on the presence or absence of a photopolymerization initiator, but is preferably about 0.1 to 100 mW/ ^cm2 .

(Example of the composition of anticorrosive adhesive tape)
1 to 4 show examples of the configuration of the anticorrosive adhesive tape of the present invention.
1, an adhesive tape 10 for corrosion prevention is provided on one surface 15A of a metal layer 15 made of a metal having a lower potential than iron, and an adhesive layer 11 containing an anisotropic conductive material 13 is provided. The adhesive layer 11 has a surface 11A opposite to the surface on which the metal layer 15 is provided attached to an adherend.

In the anticorrosive adhesive tape 10 shown in FIG. 2, an adhesive layer 11 containing anisotropic conductive material 13 is provided on one surface 15A of a metal layer 15 of a metal foil made of a metal with a lower potential than iron. Furthermore, an adhesive layer 16 not containing a conductive material is provided on a surface 15B of the metal layer 15 on which the adhesive layer 11 is not provided. A substrate 14 is provided on a surface 16A of the adhesive layer 16 on which the metal layer 15 is not provided. Details of the substrate 14 are as described above. With this configuration, the adhesive layer 11 is protected by the substrate 14, and the anticorrosive adhesive tape has better corrosion resistance.

In the anticorrosive adhesive tape 10 shown in FIG. 3, an adhesive layer 11 containing anisotropic conductive material 13 and non-anisotropic conductive material 12 is provided on one surface 15A of a metal layer 15 made of a metal with a lower potential than iron. This allows the content of conductive materials 12, 13 in the adhesive layer 11 to be increased, further improving the anticorrosive properties of the anticorrosive adhesive tape 10.

In the anticorrosive adhesive tape 10 shown in FIG. 4, an adhesive layer 11 containing an anisotropic conductive material 13 and a non-anisotropic conductive material 12 is provided on one surface 15A of a metal layer 15 of a metal having a lower potential than iron. Furthermore, an adhesive layer 16 not containing a conductive material is provided on a surface 15B of the metal layer 15 on which the adhesive layer 11 is not provided. Furthermore, a substrate 14 other than a metal foil of a metal having a lower potential than iron is provided on a surface 16A of the adhesive layer 16 on which the metal layer 15 is not provided.

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

<Evaluation method>
In the examples and comparative examples, the anticorrosive adhesive tapes were evaluated by the following evaluation methods.
(Total light transmittance)
The total light transmittance Y of the pressure-sensitive adhesive layer was measured in accordance with JIS K7361-1. Specifically, the total light transmittance Y was measured using a haze meter (e.g., Haze Meter NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd.) in an atmosphere of 23°C and humidity 50%.
The total light transmittance X per 1 μm of thickness was calculated from the total light transmittance Y and the thickness T (μm) of the pressure-sensitive adhesive layer according to the following formula.

(Resistance value)
After peeling off the release sheet, the 50 mm x 50 mm anticorrosive adhesive tapes obtained in each Example and Comparative Example were measured according to their resistance value as follows. Anticorrosive adhesive tapes with high resistance (resistance value of 10 ⁴ Ω or more) were measured by attaching an electrode URS probe (manufactured by Mitsubishi Chemical Analytech) to a resistivity meter Hiresta-UP MCP-HT450 (manufactured by Mitsubishi Chemical Analytech) and bringing the electrode into contact with the surface of the anticorrosive adhesive tape. Anticorrosive adhesive tapes with low resistance (resistance value less than 10 ⁴ Ω) were measured by attaching an in-line four-needle probe (manufactured by Mitsubishi Chemical Analytech) to a low resistivity meter Loresta-AX MCP-T370 (manufactured by Mitsubishi Chemical Analytech) and bringing the electrode into contact with the surface of the anticorrosive adhesive tape.

(Sacrificial corrosion protection evaluation)
The anticorrosive adhesive tape of 150 mm x 70 mm obtained in each Example and Comparative Example was attached to a steel plate SS400 (manufactured by TP Giken Co., Ltd., 150 mm x 70 mm) as an adherend by peeling off the release sheet. Then, a part of the anticorrosive adhesive tape (3 mm x 3 mm) was cut out, a 3% by mass NaCl aqueous solution was dripped onto it, and a silver/silver chloride electrode was used so that the tip of the electrode was in contact with the NaCl aqueous solution, and the potential was measured. In measuring the potential, a digital multimeter "CDM-11D" (manufactured by Custom Co., Ltd.) was used as a tester, and its negative pole and the electrode "HS-205C" (manufactured by Toa DKK Co., Ltd.) were connected with an electrode clip and used. The sacrificial anticorrosive properties were evaluated according to the following evaluation criteria based on the measured potential.
A: The potential was −700 mV or less, and the sacrificial corrosion protection was good.
B: The potential was greater than -700 mV, and the sacrificial corrosion protection was insufficient.

(Adhesive Strength Evaluation)
The adhesive strength of the pressure-sensitive adhesive layer prepared in each of the Examples and Comparative Examples was measured as follows.
The anticorrosive adhesive tape obtained in each example was cut to a length of 100 mm x 25 mm, and then bonded to a SUS plate via the adhesive layer to prepare a measurement sample. The bonding to the SUS plate was performed by moving a 2 kg roller back and forth twice in total at a speed of 10 ± 0.5 mm/s.
The measurement sample was fixed to the chuck of a tensile tester ("Tensilon Universal Material Tester" manufactured by A & D Co., Ltd.). Then, the anticorrosive adhesive tape was pulled for 60 mm or more at a peel angle of 180° and a speed of 300 mm/min in an environment of 23°C and 50% RH, and the average value of the load (N) detected by the load cell was recorded and defined as the adhesive strength (N/25 mm).
A: The adhesive strength was 30 N/25 mm or more, and the adhesiveness was quite good.
B: The adhesive strength was 10 N·25 mm or more and less than 30 N/25 mm, and the adhesiveness was good.
C: The adhesive strength was less than 10 N/25 mm, and the adhesiveness was insufficient.

[Examples 1 to 4 and Comparative Examples 1 to 3]
A pressure-sensitive adhesive having the composition shown in Table 1 was prepared, and an anisotropic conductive material or a non-anisotropic conductive material was mixed with the pressure-sensitive adhesive to obtain a pressure-sensitive adhesive composition in the content ratio shown in Table 2. Nitrogen was purged into the pressure-sensitive adhesive composition to remove dissolved oxygen. Next, a spacer having the same thickness as the target thickness was placed on the release-treated surface of the release sheet, and the pressure-sensitive adhesive composition was applied onto the release-treated surface of the release sheet. Next, another release sheet was covered on the applied pressure-sensitive adhesive composition so that the release-treated surface was in contact with the pressure-sensitive adhesive composition. As the release sheet, a silicone release-treated PET film (thickness 50 μm) was used.
In this state, the lamp intensity of the chemical lamp was adjusted so that the ultraviolet irradiation intensity on the release sheet on the coated side was 5 mW/ ^cm2 , and ultraviolet rays were irradiated for 15 minutes to obtain an adhesive layer with release sheets attached to both sides. The gel fraction was 55%. A metal layer (zinc foil, thickness 50 μm) was attached to one side of this adhesive layer to prepare an anticorrosive adhesive tape. The resistance value, sacrificial corrosion protection, and adhesive strength of the obtained anticorrosive adhesive tape were evaluated. The evaluation results are shown in Table 2.

*The components in Table 1 are as follows.
Olefin polymer: trade name "L-1253", manufactured by Kuraray Co., Ltd., hydrogenated polybutadiene having a (meth)acryloyl group at one end Tackifying resin 1: trade name "Arcon P140", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 140°C
Tackifier resin 2: Product name "Alcon P100", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100°C
Fine particles: Trade name "Cellstar Z-27", manufactured by Tokai Kogyo Co., Ltd. Glass balloons Crosslinking agent: Trade name "TEAI-1000", manufactured by Nippon Soda Co., Ltd. Polymerization initiator: 2,2-dimethoxy-2-phenylacetophenone

The components in Table 2 are as follows.
Anisotropic conductive material: carbon nanotubes (CNT), manufactured by JEIO, product name "JENOTUBE8A", average diameter 6 to 9 nm, average length 100 to 200 μm
Non-anisotropic conductive material: Carbon black, manufactured by Oriental Sangyo Co., Ltd., product name "AT-NO. 15S"

As is clear from the results of Examples 1 to 4 above, it was found that the anticorrosive adhesive tape can achieve both excellent corrosion resistance and good adhesion by having the metal layer be a metal foil made of a metal with a lower potential than iron and the adhesive layer contain an anisotropic conductive material. On the other hand, as is clear from the results of Comparative Examples 1 to 3, it was found that the anticorrosive adhesive tape cannot achieve both excellent corrosion resistance and good adhesion unless the adhesive layer contains an anisotropic conductive material, even if the metal layer is a metal foil made of a metal with a lower potential than iron.

REFERENCE SIGNS LIST 10 Anticorrosive adhesive tape 11 Adhesive layer 12 Non-anisotropic conductive material 13 Anisotropic conductive material 14 Substrate 15 Metal layer 16 Adhesive layer

Claims (9)

A metal layer and a pressure-sensitive adhesive layer provided on at least one surface of the metal layer,
the metal layer is a layer of a metal having a lower potential than iron,
the pressure-sensitive adhesive layer contains an anisotropic conductive material,
the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer is at least one pressure-sensitive adhesive selected from the group consisting of an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, and a silicone pressure-sensitive adhesive,
A corrosion-preventive adhesive tape , wherein the content of the anisotropic conductive material in the adhesive layer is 0.008 to 0.5 parts by mass per 100 parts by mass of the adhesive . The adhesive tape according to claim 1, wherein the total light transmittance X per 1 μm of thickness of the adhesive layer is 99.85% or less. The anticorrosive adhesive tape according to claim 1 or 2, wherein the aspect ratio of the anisotropic conductive material is 2 or more. The anticorrosive adhesive tape according to any one of claims 1 to 3, wherein the anisotropic conductive material is a carbon-based material. The anticorrosive adhesive tape according to claim 4, wherein the carbon-based material is carbon nanotubes. The anticorrosive adhesive tape according to any one of claims 1 to 5, wherein the pressure-sensitive adhesive layer has a resistance value of 1 x 10 ⁸ to 1 x 10 ¹⁴ Ω. The anticorrosive adhesive tape according to any one of claims 1 to 6, wherein the thickness of the adhesive layer is 20 μm or more. The anticorrosive adhesive tape according to any one of claims 1 to 7, wherein the metal layer is zinc foil. The anticorrosive adhesive tape according to any one of claims 1 to 8, wherein the thickness of the metal layer is 2.5 μm or more.