Anticorrosion adhesive tape and corrosion prevention method for steel structures

Abstract

To provide an anticorrosive material that has excellent work efficiency but yet exerts excellent anticorrosive effect even when disposed between two structures, and an anticorrosive method for steel structures using the anticorrosive material.SOLUTION: An anticorrosive adhesive tape 10 is disposed between a first structure 20 and a second structure 30. The first structure 20 is a steel structure and the anticorrosive adhesive tape 10 has an adhesive layer 11. An anticorrosive method for steel structures has the steps for: bonding the anticorrosive adhesive tape 10 to the first structure 20; and placing at least one of the first and second structures 20, 30 so that the anticorrosive adhesive tape is disposed between the first and second structures 20, 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an anticorrosive adhesive tape and a method for preventing corrosion of a steel structure using the anticorrosive adhesive tape. [Background technology]

[0002] Anticorrosive coating compositions containing zinc are widely used to protect steel structures from corrosion (see, for example, Patent Document 1). By applying the anticorrosive coating composition described in Patent Document 1 to a steel structure, the steel structure can be shielded from substances that affect corrosion, such as oxygen, water, and corrosive substances. Furthermore, zinc is a metal with a lower potential than iron and has a sacrificial anticorrosion effect, so the anticorrosive coating composition described in Patent Document 1 has high corrosion prevention properties. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-143273 Summary of the Invention [Problem to be solved by the invention]

[0004] However, corrosion protection using a coating composition requires a drying process after application, which takes time, and reduces work efficiency when performing local repairs, for example, in civil engineering and construction applications such as bridges. Furthermore, if another member is placed on the coating without allowing it to dry in order to shorten the work time, a coating film cannot be formed properly, and sufficient corrosion protection cannot be ensured. Therefore, the present invention aims to provide a corrosion-resistant material that has excellent work efficiency and good corrosion protection even when placed between two structures, and a corrosion protection method for steel structures using the corrosion-resistant material. [Means for solving the problem]

[0005] As a result of extensive research, the inventors have discovered that adhesive tape is a corrosion-resistant material that is highly efficient to work with and has good corrosion protection even when placed between two structures, and have completed the present invention as described below. That is, the present invention provides the following [1] to

[12] . [1] A corrosion-prevention adhesive tape that is disposed between a first structure and a second structure, the first structure being a steel structure, and that has an adhesive layer. [2] The corrosion-resistant adhesive tape described in [1] above, wherein the second structure is at least one type of structure selected from the group consisting of concrete structures, mortar structures, steel structures, metal structures other than steel, thermoplastic resin structures, thermosetting resin structures, and fiber-reinforced plastic structures. [3] The anticorrosion adhesive tape according to [1] or [2] above, which consists solely of the adhesive layer. [4] The corrosion prevention adhesive tape according to any one of the above [1] to [3], wherein the adhesive layer contains a metal having a lower potential than iron. [5] The anticorrosion adhesive tape according to any one of the above [1] to [4], further comprising a substrate, the adhesive layer being provided on one surface of the substrate. [6] The anticorrosion adhesive tape according to the above [5], wherein the substrate is at least one sheet-like material selected from the group consisting of a resin film, a nonwoven fabric, and a metal foil. [7] A metal layer is further provided, and the pressure-sensitive adhesive layer is provided on one side of the metal layer; The anticorrosion adhesive tape according to the above [1] or [2], wherein the metal layer is a layer of a metal having a lower potential than iron. [8] The anticorrosion adhesive tape according to the above [4] or [7], wherein the metal having a lower potential than iron is zinc. [9] The anticorrosion adhesive tape according to any one of [4], [7], and [8] above, wherein the adhesive layer contains a conductive material other than the metal having a lower potential than iron.

[10] The anticorrosion adhesive tape according to [9] above, wherein the conductive material is carbon nanotubes.

[11] The anticorrosion pressure-sensitive adhesive tape according to any one of the above [1] to

[10] , wherein the pressure-sensitive adhesive layer has a storage modulus G' at 23°C of 50,000 to 1,000,000 Pa.

[12] A method for preventing corrosion of steel structures, comprising the steps of: applying the anticorrosion adhesive tape described in any one of [1] to

[11] above to the first structure; and installing at least one of the first and second structures so that the anticorrosion adhesive tape is positioned between the first and second structures. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a corrosion-resistant material that has excellent work efficiency and good corrosion protection even when placed between two structures, and a corrosion protection method for steel structures using the corrosion-resistant material. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an example of use of an anticorrosion adhesive tape according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic view showing an example of use of a modified example of the anticorrosion adhesive tape according to one embodiment of the present invention. [Figure 3] FIG. 3 is a schematic view showing an example of use of a modified example of the anticorrosion adhesive tape according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic view showing an example of use of a modified example of the anticorrosion adhesive tape according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Anti-corrosion adhesive tape] An anticorrosion adhesive tape according to one embodiment of the present invention will be described with reference to FIG. 1 . The anticorrosion adhesive tape 10 according to one embodiment of the present invention is disposed between a first structure 20 and a second structure 30. The first structure 20 is a steel structure, and the anticorrosion adhesive tape 10 includes an adhesive layer 11. Because the anticorrosion adhesive tape 10 according to one embodiment of the present invention is an adhesive tape, it can insulate the first structure 20 from substances that affect corrosion, such as oxygen, water, and corrosive substances, simply by being attached to the first structure 20. Therefore, coating and drying are not required to form a layer that insulates the first structure 20 from substances such as oxygen, water, and corrosive substances. Furthermore, since the second structure 30 can be placed adjacent to the first structure 20 without a drying time, the anticorrosion adhesive tape 10 according to one embodiment of the present invention not only has excellent work efficiency but also exhibits good anticorrosion properties even when disposed between two structures. Examples of steel structures include bridges, steel towers, viaducts, tanks, plants, and bridge piers. The metal material constituting the steel structure is, for example, a metal material containing at least one selected from the group consisting of iron and iron-containing alloys. Specific examples of the iron-containing alloy include alloy steels such as nickel-chromium steel, nickel-chromium-molybdenum steel, chromium steel, chromium-molybdenum steel, and manganese steel, as well as various steel materials such as carbon steel.

[0009] The second structure 30 is not particularly limited as long as it is a structure used in combination with a steel structure. Examples of the second structure 30 include concrete structures, mortar structures, steel structures, metal structures other than steel, thermoplastic resin structures, thermosetting resin structures, and fiber-reinforced plastic structures. These structures can be used alone or in combination of two or more. For example, in a steel highway bridge, the H-beams of the floor structure are the first structure, and the concrete deck slab placed on top of the floor structure members is the second structure.

[0010] <Metals with a lower potential than iron> The adhesive layer 11 preferably contains a metal having a lower potential than iron. By containing a metal having a lower potential than iron (hereinafter also referred to as "sacrificial corrosion protection metal"), the adhesive layer 11 has sacrificial corrosion protection properties, thereby enhancing the corrosion protection of the first structure 20. The sacrificial corrosion protection metal is dispersed in the adhesive that constitutes the adhesive layer 11.

[0011] Examples of sacrificial corrosion protection metals include cadmium, chromium, zinc, manganese, and aluminum. Of these, zinc and aluminum are preferred, with zinc being particularly preferred. The use of zinc provides excellent sacrificial corrosion protection.

[0012] The sacrificial corrosion protection metal may be dispersed in the pressure-sensitive adhesive as a filler in any form, such as a particle form, a scale form, a spindle form, etc., but is preferably in a particle form. By making the sacrificial corrosion protection metal in a particle form, it becomes easier to disperse in the pressure-sensitive adhesive layer 11 without substantially reducing the adhesiveness of the pressure-sensitive adhesive layer 11. In this specification, the particulate shape refers to a shape in which the ratio of the length in the major axis direction to the length in the minor axis direction (aspect ratio) is small, for example, an aspect ratio of 3 or less, preferably 2 or less. The particle shape is not particularly limited, and may be spherical or may be an amorphous shape such as powder. The particle size of the above particulate metal is, for example, 1 to 500 μm, preferably 1 to 200 μm. In this specification, the particle size refers to the average particle size measured by laser diffraction.

[0013] The content of the sacrificial anticorrosive metal in the adhesive layer 11 is, for example, 1 to 30 mass %, preferably 3 to 25 mass %, and more preferably 7 to 20 mass %, based on the total mass of the adhesive layer 11. If the content of the sacrificial anticorrosive metal is equal to or greater than these lower limits, the anticorrosive performance will be enhanced, and if it is equal to or less than these upper limits, the adhesive strength will be enhanced.

[0014] <Conductive materials> The pressure-sensitive adhesive layer 11 preferably contains, in addition to the sacrificial metal, a conductive material other than the sacrificial metal. The conductive material may be 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, graphene, carbon nanotubes, and acetylene black. Examples of metal-based materials include iron, or metals with a more noble potential than iron, such as gold, silver, copper, nickel, or alloys containing these metals. 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 ionic polymers include sodium polyacrylate and potassium polyacrylate. The conductive material may be used alone or in combination of two or more. Among the above, carbon-based materials are preferred as the conductive material, and carbon nanotubes are more preferred.

[0015] <Carbon nanotubes> The pressure-sensitive adhesive layer 11 preferably contains carbon nanotubes. The inclusion of carbon nanotubes improves the sacrificial corrosion protection of the pressure-sensitive adhesive layer 11 and allows the adhesive strength to be maintained at a high level, making it easier to obtain an anticorrosion adhesive tape 10 that combines high adhesive strength and sacrificial corrosion protection. This is presumably because, although carbon nanotubes are a conductive material, a smaller amount is required to exhibit a certain level of sacrificial corrosion protection compared to other types of conductive materials, and therefore the degree of decrease in adhesive strength is smaller.

[0016] Carbon nanotubes are tubular materials made from carbon. They have excellent electrical properties, and when combined with resins, they can be used to form highly conductive sheets. Carbon nanotubes are made of graphite sheets with a hexagonal mesh of carbon atoms rolled into a cylindrical shape. Nanotubes rolled in one layer are called single-wall carbon nanotubes, while nanotubes rolled in multiple layers are called multi-wall carbon nanotubes. In the anticorrosion adhesive tape 10 according to one embodiment of the present invention, the type of carbon nanotubes is not particularly limited, and may be any of single-walled carbon nanotubes, multi-walled 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 also be used.

[0017] The carbon nanotubes preferably have an average diameter of 1 to 100 nm, more preferably 2 to 15 nm. The carbon nanotubes preferably have an average length of 0.1 to 1,000 μm, more preferably 10 to 500 μm. The carbon nanotubes preferably have an aspect ratio (average length / average diameter) of 10 to 100,000, more preferably 500 to 30,000. The diameter of a carbon nanotube refers to the outer diameter in the case of a single-walled carbon nanotube, and the outer diameter of the outermost tube in the case of a multi-walled carbon nanotube. The diameter and length of a carbon nanotube can be measured, for example, from an image obtained by observation with a transmission electron microscope (TEM), and the average diameter and average length can be calculated by taking the arithmetic mean of any 50 nanotubes.

[0018] From the viewpoint of the sacrificial corrosion protection and adhesive strength of the pressure-sensitive adhesive layer 11, the content of the conductive material in the pressure-sensitive adhesive layer 11 is preferably 0.005 to 30 mass%, more preferably 0.005 to 20 mass%, and even more preferably 0.006 to 10 mass%, based on the total amount of the pressure-sensitive adhesive layer 11. Furthermore, when a conductive material other than carbon nanotubes is used, from the viewpoint of sacrificial corrosion protection, it is preferable to contain a relatively large amount of the conductive material, and specifically, the content of the conductive material is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, and even more preferably 2 to 10 mass%.

[0019] When the conductive material is carbon nanotubes, the content of the carbon nanotubes in the adhesive layer 11 is preferably 0.0005 to 0.7 mass %, more preferably 0.005 to 0.05 mass %, and even more preferably 0.006 to 0.045 mass %, based on the total amount of the adhesive layer 11. When the carbon nanotube content is equal to or greater than these lower limit values, the sacrificial corrosion resistance is likely to be enhanced, and when the carbon nanotube content is equal to or less than these upper limit values, the adhesive strength is likely to be improved.

[0020] <Adhesive> The adhesive layer 11 is preferably formed of an adhesive. The type of adhesive is not particularly limited, but examples include acrylic adhesives, rubber adhesives, urethane adhesives, and silicone adhesives. These may be used alone or in combination. Among these, it is preferable that the pressure-sensitive adhesive layer 11 be formed from an acrylic pressure-sensitive adhesive.

[0021] (acrylic adhesive) Hereinafter, a more detailed description will be given of one embodiment of the acrylic pressure-sensitive adhesive used in the pressure-sensitive adhesive layer 11. The acrylic pressure-sensitive adhesive is an 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 that can include not only compounds having no repeating units, but also compounds that copolymerize with the (meth)acrylic acid alkyl ester-based monomer (A), such as the olefin polymer (C) described below, which monomer itself has repeating units.

[0022] ((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 number of carbon atoms in the alkyl group of the aliphatic alcohol is preferably 2 to 14, more preferably 4 to 10. When the number of carbon atoms in the alkyl group is within this range, it is easy to adjust the storage modulus at 23°C and adhesive strength of the pressure-sensitive adhesive to the above-mentioned ranges.

[0023] 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-based monomers may be used alone or in combination of two or more kinds.

[0024] The structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) constitutes the main component of the pressure-sensitive adhesive layer, and its content is generally 30% by mass or more, preferably 50% by mass or more, and more preferably 70% by mass or more, based on the total amount of the pressure-sensitive adhesive layer. Increasing the content of the (meth)acrylic acid alkyl ester monomer (A) thus makes it possible to impart a desired adhesive strength to the pressure-sensitive adhesive layer. Furthermore, the content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) is, for example, 97% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less, in order to contain a certain amount or more of other components. The content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) in the pressure-sensitive adhesive layer 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 interchangeably. The same applies to components other than component (A), such as components (B) and (C) described below.

[0025] (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. Use of the polar group-containing monomer (B) makes it easier to improve adhesive strength to an adherend. 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.

[0026] 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 pressure-sensitive adhesive layer 11 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 improve the adhesive strength to the first structure 20.

[0027] (olefin polymer (C)) The polymerizable monomer preferably further contains an olefin polymer (C) having a polymerizable bond at one end. By using such an olefin polymer (C), the adhesive strength to the first structure 20 can be easily improved. The polymerizable bond means an unsaturated carbon-carbon bond that can be polymerized with a polymerizable monomer, and examples thereof include an unsaturated double bond, and preferably a (meth)acryloyl group. The olefin polymer (C) may be a polyolefin having a (meth)acryloyl group at one end. The polyolefin is a polymer of an aliphatic hydrocarbon compound having a double bond, such as ethylene, propylene, butane, butadiene, or isoprene, or a hydrogenated product thereof.

[0028] Examples of polyolefins having a (meth)acryloyl group at 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. Also included are polybutadienes having a (meth)acryloyl group at one end or hydrogenated products thereof, such as "L-1253" manufactured by Kuraray Co., Ltd.

[0029] The olefin polymer (C) has a number average molecular weight of 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. Furthermore, the content of the structural units derived from the olefin polymer (C) in the pressure-sensitive adhesive layer 11 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 units derived from the (meth)acrylic acid alkyl ester-based monomer (A).

[0030] (Crosslinking agent (D)) The polymerizable monomer preferably further contains a crosslinking agent. Examples of the crosslinking agent include a polyfunctional monomer having two or more vinyl groups, and preferably a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups. Use of a polyfunctional monomer makes it easier to adjust the adhesive strength of the pressure-sensitive adhesive layer to an appropriate range. The polyfunctional (meth)acrylate is not particularly limited, and examples thereof include hexanediol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, proxilated trimethylolpropane triacrylate, proxilated glyceryl triacrylate, neopentyl glycol adipate diacrylate, and the like, as well as polymers such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and liquid hydrogenated 1,2-polybutadiene di(meth)acrylate. Among these polyfunctional (meth)acrylates, polymers are preferred, and liquid hydrogenated 1,2-polybutadiene diacrylate is more preferred. Commercially available liquid hydrogenated 1,2-polybutadiene diacrylates include "TEAI-1000" manufactured by Nippon Soda Co., Ltd. Furthermore, the content of the structural units derived from the crosslinking agent in the adhesive layer 11 is preferably 0.1 to 4 parts by mass, more preferably 0.3 to 3 parts by mass, and even more preferably 0.5 to 2 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[0031] (tackifying resin) The acrylic pressure-sensitive adhesive may contain a tackifying resin from the viewpoint of improving adhesive strength. As the tackifying resin, a tackifying resin with low polymerization inhibition property such as hydrogenated terpene resin, hydrogenated rosin, disproportionated rosin resin, petroleum resin, etc. is preferable. Among these, hydrogenated tackifying resins are preferable because tackifying resins with many double bonds inhibit the polymerization reaction, and hydrogenated petroleum resins are particularly preferable. From the viewpoint of improving the cohesive strength and adhesive strength of the PSA, the softening point of the tackifier resin may be about 95° C. or higher, but preferably includes one that is 120° C. or higher, and for example, one that is 95° C. or higher but lower than 120° C. may be used in combination with one that is 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 tackifying resin in the acrylic 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, per 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A).

[0032] (fine particles) The acrylic adhesive may contain fine particles, which can improve adhesive strength. Examples of fine particles include inorganic hollow particles such as glass balloons, shirasu balloons, and fly ash balloons; organic hollow particles made of polymethyl methacrylate, acrylonitrile-vinylidene chloride copolymer, polystyrene, and phenolic resin; inorganic fine particles such as glass beads, silica beads, and synthetic mica; and organic fine particles such as ethyl polyacrylate, polyurethane, polyethylene, and polypropylene. The content of the fine particles in the acrylic pressure-sensitive adhesive is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.7 to 5 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[0033] (Other ingredients) The acrylic adhesive used in the adhesive layer 11 may contain, in addition to the components described above, various additives conventionally used in adhesives, such as plasticizers, softeners, pigments, dyes, photopolymerization initiators, and flame retardants.

[0034] (Acrylic pressure-sensitive adhesive and method for producing pressure-sensitive adhesive layer) The acrylic pressure-sensitive adhesive can be obtained by irradiating a pressure-sensitive adhesive composition containing the above-mentioned polymerizable monomer, sacrificial anticorrosive metal, and carbon nanotubes with light to polymerize the polymerizable monomer. The pressure-sensitive adhesive composition may also contain at least one of the above-mentioned tackifier resin, fine particles, and other components, as needed. More specifically, first, a polymerizable monomer, a sacrificial anticorrosive metal, and carbon nanotubes, as well as a tackifier resin, fine particles, and other components that are optionally blended, are placed in 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 pressure-sensitive adhesive composition, an inert gas such as nitrogen gas is generally supplied to purge the oxygen. Then, the pressure-sensitive adhesive composition is applied onto a release sheet, or onto a support such as a resin film, woven fabric, or nonwoven fabric, and then irradiated with light to polymerize the polymerizable monomer, thereby obtaining a pressure-sensitive adhesive layer. The steps from the application or impregnation of the pressure-sensitive adhesive composition to the light irradiation 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 support, or the like, in order to increase the viscosity.

[0035] (rubber adhesive) Next, the rubber-based adhesive used in the adhesive layer 11 will be described. The rubber-based adhesive contains a rubber component and a tackifying 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 mass. Here, diblock refers to a diblock composed of styrene and isoprene. By setting the diblock ratio within the above range, it becomes easier to increase adhesive strength. In addition to diblocks, styrene-isoprene block copolymers also include those having three or more blocks, such as triblocks composed of styrene, isoprene, and styrene blocks.

[0036] The amount of styrene in the styrene-isoprene block copolymer is not particularly limited, but is preferably 14 to 24% by mass, more preferably 15 to 18% by mass. If the amount of styrene is 14% by mass or more, the adhesive tends to have high cohesive strength. If the amount of styrene is 24% by mass or less, the cohesive strength becomes moderate and adhesive strength is easily exerted. 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 here refers to a molecular weight measured as polystyrene equivalent by GPC (gel permeation chromatography).

[0037] Various tackifying resins can be used for rubber-based adhesives, but petroleum-based resins, terpene resins, and coumarone resins are preferred. While one tackifying resin may be used alone or in combination with two or more, it is preferred to use a petroleum-based resin in combination with at least one selected from terpene resins and coumarone resins. Such a combination of tackifying resins facilitates improved adhesive strength. Examples of petroleum-based resins include aliphatic petroleum resins (C5 petroleum resins), alicyclic petroleum resins, and aromatic petroleum resins, with aliphatic petroleum resins being preferred from the viewpoint of compatibility with styrene-isoprene block copolymers. Furthermore, it is preferable to use petroleum-based resins with a softening point of about 90 to 120°C. The terpene resin used may have a softening point of about 80 to 120° C., but from the viewpoint of ensuring adhesive strength, it is preferable to use a terpene resin having a softening point of less than 100° C. The coumarone resin used should preferably have a softening point of 110 to 130° C., more preferably 115 to 125° C., in order to ensure cohesive strength.

[0038] 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 becomes possible to improve the cohesive force and impart appropriate adhesive strength. 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, as in the acrylic-based adhesive, and may also contain, as necessary, a sacrificial anticorrosive metal, a conductive material, a softener, an antioxidant, a filler, etc.

[0039] (urethane adhesive) The urethane-based 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 polyols, polyester polyols, polycarbonate polyols, and polycaprolactone polyols. Examples of the polyisocyanate compounds include diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate. These urethane adhesives may be used alone or in combination of two or more. The urethane-based adhesive may be a urethane resin obtained by reacting a polyurethane polyol with a polyfunctional isocyanate curing agent. Examples of the polyurethane polyol include a reaction product of the above-mentioned polyol with a polyisocyanate compound, or a reaction product of a polyol, a polyisocyanate compound, and a chain extender such as a diamine. The polyfunctional isocyanate curing agent may be any compound having two or more isocyanate groups, and the above-mentioned isocyanate compounds can be used. The urethane-based adhesive may contain the above-mentioned fine particles in addition to the urethane resin, and may also contain a tackifying resin, a sacrificial anticorrosive metal, a conductive material, a softener, an antioxidant, a filler, etc., as necessary.

[0040] (Silicone adhesive) Examples of silicone-based adhesives include addition reaction type, peroxide curing type, and condensation reaction type silicone-based adhesives. Among these, addition reaction type silicone-based adhesives are preferably used from the viewpoint of being able to cure at low temperature in a short time. Note that addition reaction type silicone-based adhesives cure when the adhesive layer is formed. When an 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 adhesive may contain fine particles, and may also contain a crosslinking agent and various additives for controlling adhesive strength.

[0041] <Storage modulus G'> The pressure-sensitive adhesive layer 11 preferably has a storage modulus G' at 23°C of 50,000 to 1,000,000 Pa. When the storage modulus G' at 23°C of the pressure-sensitive adhesive layer 11 is 50,000 or more, the pressure-sensitive adhesive layer 11 has good corrosion prevention performance. When the storage modulus G' at 23°C is 50,000 or more, if the pressure-sensitive adhesive layer 11 is damaged by an external impact or the like, the resin flows in a direction to restore the damaged area, and the force to restore the damaged area (hereinafter also referred to as self-repairing force) becomes strong. This makes it possible to prevent a decrease in the corrosion prevention function of the first structure 20 due to exposure of the surface of the first structure 20 or partial thinning of the pressure-sensitive adhesive layer 11. When the storage modulus G' of the anticorrosive adhesive at 23°C is 1,000,000 or less, the corrosion prevention function of the first structure 1 is improved. When the storage modulus G' at 23°C is 1,000,000 or less, the fluidity of the resin constituting the adhesive layer 11 is increased, and when the adhesive is damaged, the damaged area is more easily blocked by the resin, and the self-repairing ability is strengthened. As a result, similar to the above case, it is thought that the corrosion prevention function of the first structure 20 is improved. The adhesive layer 11 has a storage modulus G' at 23°C of 50,000 to 1,000,000 Pa, and the resin that constitutes the adhesive layer 11 has appropriate elasticity and viscosity. Therefore, it is thought that the adhesive layer 11 has a high self-repairing ability when damaged by external impact, etc., and has high corrosion prevention performance. The storage modulus G' of the pressure-sensitive adhesive layer 11 at 23°C is more preferably 100,000 to 800,000 Pa, and even more preferably 150,000 to 600,000 Pa. When the storage modulus G' at 23°C is within this range, the self-repairing ability of the pressure-sensitive adhesive layer 11 is enhanced, and the anticorrosion performance is improved. The storage modulus G' can be calculated by measuring the dynamic viscoelastic spectrum using, for example, a DVA-200 (manufactured by IT Measurement & Control Co., Ltd.) under the following conditions: shear mode: 10 Hz, strain: 0.1%, temperature range: -100°C to 100°C, and heating rate: 10°C / min.

[0042] The thickness of the adhesive layer 11 is, for example, 20 μm or more, preferably 40 μm or more. A thickness of 20 μm or more makes it possible to exhibit appropriate adhesion and sacrificial corrosion protection. In order to have a good self-repair function, the adhesive layer 11 is preferably thicker; specifically, a thickness of 200 μm or more is more preferable, and in order to have an excellent self-repair function, a thickness of 400 μm or more is even more preferable. The thickness of the conductive adhesive layer 11 is not particularly limited and may be, for example, 1 cm or less. However, in order to make the anticorrosion adhesive tape 10 thin, the thickness is preferably 1500 μm or less, more preferably 900 μm or less. The thickness of the adhesive layer 11 means the thickness of each adhesive layer in a double-sided adhesive tape having adhesive layers on both sides of a substrate, which will be described later.

[0043] <Anti-corrosion adhesive tape> The anticorrosion adhesive tape 10 may be, for example, a double-sided adhesive tape. If a double-sided adhesive tape is used, the second structure 30 can be temporarily fixed to the first structure 20 via the anticorrosion adhesive tape 10 before the second structure 30 is permanently fixed to the first structure 20 using bolts or the like. Furthermore, if the second structure is a steel structure, both the first and second structures can be protected from corrosion. The anticorrosion adhesive tape 10 is preferably a double-sided adhesive tape consisting of only an adhesive layer (i.e., an adhesive layer alone). By using the anticorrosion adhesive tape 10 consisting of only the adhesive layer 11, the thickness of the tape can be reduced while maintaining good anticorrosion properties.

[0044] 2, the anticorrosion adhesive tape 10 may be a single-sided adhesive tape having a substrate 12 and an adhesive layer 11 provided on one side of the substrate 12. This allows the adhesive layer 11 to be protected by the substrate 12. This further improves the durability of the anticorrosion adhesive tape 10. When the second structure 30 is a concrete structure or a mortar structure, for example, ready-mixed concrete or ready-mixed mortar may be poured onto the anticorrosion adhesive tape 10 after the anticorrosion adhesive tape 10 is attached to the first structure 20. By providing the substrate 12 on the anticorrosion adhesive tape 10, the adhesive layer 11 can be protected from the ready-mixed concrete or ready-mixed mortar.

[0045] Furthermore, although not shown, the anticorrosion adhesive tape may be a double-sided adhesive tape having a substrate and adhesive layers provided on both sides of the substrate. As in the case where the anticorrosion adhesive tape is composed only of adhesive layers, this allows the second structure to be temporarily fixed to the first structure via the anticorrosion adhesive tape before the second structure is permanently fixed to the first structure using bolts or the like. In the double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the substrate, each pressure-sensitive adhesive layer is as described above. However, from the viewpoint of sacrificial corrosion protection, it is preferable that at least the pressure-sensitive adhesive layer on the side to be attached to the first structure 20 contains a sacrificial corrosion protection metal, or a sacrificial corrosion protection metal and a conductive material, and that the storage modulus G' is in the range as described above.

[0046] Examples of the substrate used in each adhesive tape include sheet-like materials such as resin films, nonwoven fabrics, and metal foils. Examples of resin films include acrylic resin films, fluorine-based resin films, propylene-based resin films, polyethylene-based resin films, polyester-based resin films, polyamide-based resin films, polyacrylic resin films, polyurethane-based resin films, polystyrene-based resin films, polyvinyl chloride-based resin films, ethylene vinyl acetate-based resin films, acrylonitrile-based resin films, and polycarbonate-based resin films. The nonwoven fabric is made of synthetic resin fibers such as polyamide, polyester, polyacrylic, polyolefin, polyurethane, etc. Examples of metal foils include metal foils of iron and its alloys, metal foils of metals with a lower potential than iron, such as chromium, zinc, titanium, aluminum, and magnesium, and metal foils of metals with a higher potential than iron, such as gold, silver, copper, tin, nickel, and cobalt. These sheet-like materials can be used alone or in combination of two or more. From the viewpoint of protecting the pressure-sensitive adhesive layer 11, the substrate is preferably a resin film. When the second structure 30 is a concrete structure or a mortar structure, the use of the above-mentioned resin film can adequately protect the pressure-sensitive adhesive layer even when ready-mixed concrete or ready-mixed mortar is poured onto the resin film. The thickness of the substrate is not particularly limited, but is, for example, 10 to 200 μm, and preferably 20 to 100 μm.

[0047] Repairs to structures are carried out while the structure is in use or by temporarily suspending its use. Therefore, repairs to structures need to be completed in a short period of time. From this perspective, the anticorrosion adhesive tape of one embodiment of the present invention is preferably used as an anticorrosion material for repairing existing structures.

[0048] <Modification 1 of Anticorrosion Adhesive Tape> The adhesive layer 11 of the corrosion-preventive adhesive tape 10 of one embodiment of the present invention preferably contains a metal with a lower potential than iron. However, the adhesive layer 11 of the corrosion-preventive adhesive tape 10 of one embodiment of the present invention does not have to contain a metal with a lower potential than iron. Even in this case, the corrosion-preventive adhesive tape 10 can insulate the first structure from substances that affect corrosion, such as oxygen, water, and corrosive substances, simply by being attached to the first structure. This allows a second structure 30 to be placed adjacent to the first structure 20 without drying time. Therefore, even when the corrosion-preventive adhesive tape 10 is placed between two structures, it can exhibit excellent work efficiency and good corrosion prevention properties.

[0049] <Modification 2 of Anticorrosion Adhesive Tape> The adhesive layer 11 of the corrosion-preventive adhesive tape 10 of one embodiment of the present invention preferably contains a metal having a lower potential than iron. However, the adhesive layer 11 of the corrosion-preventive adhesive tape 10 of one embodiment of the present invention does not necessarily contain a metal having a lower potential than iron. In this case, to enhance the corrosion resistance of the corrosion-preventive adhesive tape 10, as shown in FIG. 3 , the corrosion-preventive adhesive tape 10 preferably includes a metal layer 13 and an adhesive layer 11 on one side of the metal layer 13, and the metal layer 13 is preferably a layer of a metal having a lower potential than iron. Specific examples of metals having a lower potential than iron are as described above, and a layer of zinc is more preferred. Specifically, the metal layer 13 may be formed by adhering a metal foil made of a metal having a lower potential than iron to the surface of the adhesive layer 11. Alternatively, the metal layer 13 may be a metal film formed by coating the surface of the adhesive layer 11 with a metal by sputtering, vacuum deposition, or the like.

[0050] The metal layer 13 is formed directly on the adhesive layer 11. That is, the metal constituting the metal layer 13, which has a lower potential than iron, comes into contact with the adhesive layer 11. When the metal having a lower potential than iron comes into contact with the adhesive layer 11, electrons released upon ionization can easily migrate to the adhesive layer 11, thereby improving the corrosion resistance of the anticorrosion adhesive tape 10. Also in this case, from the viewpoint of the corrosion resistance of the anticorrosion adhesive tape 10, it is preferable that the adhesive layer 11 contain a conductive material other than a metal having a lower potential than iron.

[0051] The thickness of the metal layer 13 is preferably 2.5 μm or more. When the thickness of the metal layer 13 is 2.5 μm or more, the metal layer 13 can sufficiently supply electrons generated by ionization of the metal in the metal layer 13 to the first structure 20, thereby maintaining sufficient corrosion resistance of the corrosion-preventive adhesive tape 10. From the viewpoint of improving the corrosion resistance of the corrosion-preventive adhesive tape 10, the thickness of the metal layer 13 is more preferably 5 μm or more. Furthermore, from the viewpoint of ensuring the flexibility of the corrosion-preventive adhesive tape 10 and improving the handleability of the corrosion-preventive adhesive tape 10, the thickness of the metal layer 13 is preferably 200 μm or less, more preferably 100 μm or less.

[0052] 4, the anticorrosive adhesive tape 10 may further include a substrate 12 and a metal layer 13 provided on one side of the substrate 12, with an adhesive layer 11 provided on one side of the metal layer 13, the metal layer 13 being a layer of a metal having a lower potential than iron. Because the metal layer 13 is protected by the substrate 12, the anticorrosive properties of the anticorrosive adhesive tape 10 can be further improved. Also in this case, from the viewpoint of the anticorrosive properties of the anticorrosive adhesive tape 10, it is preferable that the adhesive layer 11 contains a conductive material other than a metal having a lower potential than iron. In this case, the metal layer 13 may be adhered to the substrate 12 with an adhesive or the like, or may be formed on the substrate 12 by sputtering, vacuum deposition, or the like.

[0053] Furthermore, even when the anticorrosion adhesive tape includes a metal layer that is a layer of a metal having a potential more base than iron, the adhesive layer may contain a metal having a potential more base than iron, thereby suppressing corrosion of the first structure with both the metal in the metal layer having a potential more base than iron and the metal in the adhesive layer having a potential more base than iron, thereby further improving the corrosion resistance of the anticorrosion adhesive tape.

[0054] The anticorrosion adhesive tape of the present invention may have a release sheet attached to the surface of the adhesive layer. The release sheet is preferably peeled from the adhesive layer before using the anticorrosion adhesive tape to expose the adhesive layer, and the exposed adhesive layer is then attached to a structure. For example, in a double-sided adhesive tape, release sheets may be attached to both sides of the tape, or to only one side of the tape. In addition, in a single-sided adhesive tape, a release sheet may be attached to one side of the exposed adhesive layer. The release sheet may be a resin film, and it is preferable that the surface to be bonded to the adhesive layer is a release-treated surface that has been subjected to release treatment with a silicone release agent or the like.

[0055] The anticorrosion adhesive tape of one embodiment of the present invention is merely one embodiment of the anticorrosion adhesive tape of the present invention, and therefore does not limit the anticorrosion adhesive tape of the present invention.

[0056] [Corrosion prevention methods for steel structures] The corrosion prevention method for steel structures of the present invention includes a step (first step) of applying the corrosion prevention adhesive tape of the present invention to a first structure, and a step (second step) of placing at least one of the first and second structures so that the corrosion prevention adhesive tape is disposed between the first and second structures. This increases the efficiency of the corrosion prevention work for steel structures, and while maintaining excellent work efficiency, it is possible to improve the corrosion prevention properties of the corrosion prevention material disposed between the two structures.

[0057] The first and second steps are preferably performed in this order. That is, it is preferable to apply the anticorrosion adhesive tape of the present invention to a first structure, and then move at least one of the first and second structures to position the second structure adjacent to the anticorrosion adhesive tape applied to the first structure. Specifically, the second structure may be positioned on top of the anticorrosion adhesive tape applied to the first structure, or may be positioned next to the anticorrosion adhesive tape applied to the first structure. Furthermore, the second structure may be positioned below the anticorrosion adhesive tape applied to the first structure. In this case, it is preferable to position the second structure in contact with the anticorrosion adhesive tape applied to the first structure. Alternatively, the second structure may be installed by pouring, for example, ready-mixed concrete or ready-mixed mortar on top of the anticorrosion adhesive tape applied to the first structure.

[0058] The first and second steps may be performed simultaneously. Specifically, in the case of a double-sided adhesive tape, the anticorrosion adhesive tape is first attached to the second structure. Next, at least one of the first and second structures is moved or otherwise set to a predetermined position, and the anticorrosion adhesive tape attached to the second structure is then attached to the first structure, so that the anticorrosion adhesive tape is positioned between the first and second structures. In this case, the positional relationship between the first and second structures is not particularly limited. The second structure may be placed above the first structure, the second structure may be placed below the first structure, or the first and second structures may be placed side-by-side.

[0059] Note that the first structure and the second structure in the corrosion protection method for steel structures of the present invention have already been explained in the section on the corrosion-protective adhesive tape of one embodiment of the present invention, so explanation of the first structure and the second structure will be omitted.

[0060] After the anticorrosion adhesive tape is placed between the first and second structures, the second structure is usually fixed to the first structure using fixing members such as bolts, rivets, etc. When the anticorrosion adhesive tape is a double-sided adhesive tape, the second structure is temporarily fixed to the first structure by placing the anticorrosion adhesive tape between the first and second structures. Then, the second structure is firmly fixed to the first structure using fixing members. Furthermore, the corrosion prevention method for a steel structure of the present invention is preferably carried out when repairing the structure, as described above. [Example]

[0061] The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

[0062] <Evaluation method> In the examples and comparative examples, the anticorrosion adhesive tapes were evaluated by the following evaluation methods. (Drying time) The time from when the anticorrosion adhesive tape was applied to the steel material until the mortar plate was placed on the adhesive tape was measured, and the drying time was evaluated according to the following evaluation criteria. ○:0 hours ×: Over 0 hours

[0063] (Corrosion resistance evaluation) A cyclic corrosion test sample was prepared by applying anticorrosion adhesive tape to a steel material and placing a mortar plate on the adhesive tape. The resulting cyclic corrosion test sample was subjected to a cyclic corrosion test in accordance with JIS K5600-7-9 (General Test Methods for Paints - Part 7: Long-Term Durability of Coating Films - Section 9: Cyclic Corrosion Test Method - Salt Spray / Dry / Wet, Cycle D). After 168 hours (28 cycles) of cyclic corrosion testing, the appearance of the cyclic corrosion test sample was observed, and the corrosion resistance was evaluated according to the following evaluation criteria. ○: No rust on steel ×: Rust has occurred on the steel material

[0064] (storage modulus) The storage modulus of the adhesive layer of the anticorrosion adhesive tape was calculated by measuring the dynamic viscoelasticity spectrum using a dynamic viscoelasticity measuring device (manufactured by IT Measurement & Control Co., Ltd., product name "DVA-200") under the following conditions: shear mode: 10 Hz, strain: 0.1%, temperature range: -100°C to 100°C, and heating rate: 10°C / min. In the case of anticorrosion adhesive tapes with a substrate, the substrate was peeled off from the adhesive layer before measuring the storage modulus of the adhesive layer.

[0065] [Example 1] Pressure-sensitive adhesive composition 1 was prepared according to the formulation shown in Table 1. Nitrogen was purged into this pressure-sensitive adhesive composition to remove dissolved oxygen. Next, a 600 μm-thick spacer was placed on the release-treated surface of the release sheet, and the pressure-sensitive adhesive composition was applied to the release-treated surface of the release sheet. Next, another release sheet was placed on top of the applied pressure-sensitive adhesive composition so that the release-treated surface was in contact with the pressure-sensitive adhesive composition. Note that a silicone release-treated PET film (thickness 50 μm) was used as the release sheet. In this state, the ultraviolet irradiation intensity on the release sheet on the coated side was 5 mW / cm 2 The lamp intensity of the chemical lamp was adjusted so that the thickness was 600 μm, and ultraviolet light was irradiated from one side for 15 minutes to obtain a corrosion-resistant double-sided adhesive tape consisting of a single adhesive layer with release sheets attached to both sides. The thickness of the adhesive layer (i.e., the double-sided adhesive tape) was 600 μm. The results are shown in Table 2.

[0066] [Example 2] An anticorrosion double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that PSA composition 2 was prepared according to the formulation shown in Table 1. The results are shown in Table 2.

[0067] [Example 3] Except for using 200 μm spacers instead of the 600 μm spacers, a double-sided pressure-sensitive adhesive tape for corrosion prevention was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0068] [Example 4] Except for using 50 μm spacers instead of the 600 μm spacers, a double-sided pressure-sensitive adhesive tape for corrosion prevention was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0069] [Example 5] The adhesive composition was applied to the release-treated surface of the release sheet. Next, instead of covering the adhesive composition 1 coated on the release-treated surface of the release sheet with another release sheet, an acrylic resin film (trade name "ACRYPLEN HBS027E", manufactured by Mitsubishi Chemical Corporation) was covered. Except for this, a single-sided anticorrosion adhesive tape was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0070] [Example 6] Pressure-sensitive adhesive composition 3 was prepared according to the formulation shown in Table 1, and pressure-sensitive adhesive composition 3 was applied to the release-treated surface of a release sheet. Instead of covering this with another release sheet, zinc foil (trade name "Zinc Foil", manufactured by Takeuchi Metal Foil & Powder Co., Ltd.) was then covered on top of this. Except for this, a single-sided pressure-sensitive adhesive tape for corrosion prevention was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0071] [Comparative Examples 1 and 2] Instead of using anticorrosion double-sided adhesive tape, an anticorrosion paint (trade name "Zettall EP-2", manufactured by Dai Nippon Toryo Co., Ltd.) was applied to form a coating film. The results are shown in Table 2.

[0072] [Table 1]

[0073] 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 Crosslinking agent: Product name "TEAI-1000", manufactured by Nippon Soda Co., Ltd. Tackifier 1: Trade name "Alcon P140", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 140°C Tackifier 2: Trade name "Alcon P100", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100°C Fine particles: Product name "Cellstar Z-27", manufactured by Tokai Kogyo Co., Ltd., glass balloon Metal with a lower potential than iron (zinc particles): Sakai Chemical Industry Co., Ltd., product name "Zinc Powder #40", average particle size: 50 μm Conductive material (CNT): Carbon nanotubes (CNT), manufactured by JEIO, product name "JENOTUBE8A", average diameter 6-9 nm, average length 100-200 μm Dispersant: Sekisui Chemical Co., Ltd., product name "S-LEC BX-L", polyvinyl butyral resin Polymerization initiator: 2,2-dimethoxy-2-phenylacetophenone

[0074] [Table 2]

[0075] The anticorrosion adhesive tapes of Examples 1 to 6 were good in both workability and anticorrosion properties. In contrast, the coating film of Comparative Example 1 was good in workability but had poor anticorrosion properties. Furthermore, the coating film of Comparative Example 2 was good in anticorrosion properties but had poor workability. [Explanation of symbols]

[0076] 10 Anti-corrosion adhesive tape 11 Adhesive layer 12 Base material 13 Metal layer 20 First Structure 30 Second Structure

Claims

1. The structure is disposed between a first structure and a second structure, the first structure is a steel structure, An adhesive layer is provided, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, or a silicone pressure-sensitive adhesive; the pressure-sensitive adhesive layer has a storage modulus G' of 50,000 to 1,000,000 Pa at 23°C; the pressure-sensitive adhesive layer contains one or more conductive materials selected from a carbon-based material, a metal-based material, a metal oxide-based material, an ionic polymer, and a conductive polymer; The corrosion-preventive adhesive tape, wherein the first structure and the second structure are architectural structures or civil engineering structures.

2. The corrosion-resistant adhesive tape according to claim 1, wherein the second structure is at least one structure selected from the group consisting of a concrete structure, a mortar structure, a steel structure, a metal structure other than steel, a thermoplastic resin structure, a thermosetting resin structure, and a fiber-reinforced plastic structure.

3. 3. The anticorrosion adhesive tape according to claim 1, which consists solely of the adhesive layer.

4. The anticorrosion adhesive tape according to any one of claims 1 to 3, wherein the adhesive layer contains a metal having a lower potential than iron.

5. The corrosion-preventing adhesive tape according to claim 1 or 2, further comprising a substrate, the adhesive layer being provided on one surface of the substrate.

6. 6. The anticorrosion pressure-sensitive adhesive tape according to claim 5, wherein the substrate is at least one sheet-like material selected from the group consisting of a resin film, a nonwoven fabric, and a metal foil.

7. Further comprising a metal layer, the pressure-sensitive adhesive layer being provided on one surface of the metal layer, 3. The corrosion-preventive adhesive tape according to claim 1, wherein the metal layer is a layer of a metal having a lower potential than iron.

8. 8. The corrosion-preventive adhesive tape according to claim 4, wherein the metal having a lower potential than iron is zinc.

9. 9. The corrosion-preventive adhesive tape according to claim 4, wherein the conductive material is a conductive material other than a metal having a lower potential than iron.

10. The corrosion-preventive adhesive tape according to claim 9, wherein the conductive material is carbon nanotubes.

11. A corrosion-resistant adhesive tape according to any one of claims 1 to 10, which is a double-sided adhesive tape.

12. A step of applying the anticorrosion adhesive tape according to any one of claims 1 to 11 to the first structure; and A corrosion prevention method for a steel structure, comprising the step of installing at least one of the first and second structures so that the corrosion prevention adhesive tape is disposed between the first and second structures.

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