Anticorrosive adhesive tape

Abstract

To provide an anticorrosive adhesive tape that has excellent anticorrosive effect on an adherend of a complicated shape.SOLUTION: A anticorrosive adhesive tape 10 has a film 11 having an elongation at break of 150% or more at 100°C, and an adhesive layer 12 provided on at least one side 11a of the film 11. The anticorrosive adhesive tape does not cause rust in a cycle corrosion test in accordance with the cycle D set forth in JIS K5600-7-9, and an adhesion of 20 N / 25 mm or more after the cycle corrosion test.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an anticorrosion adhesive tape. [Background technology]

[0002] Anticorrosion 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 due to its sacrificial corrosion protection properties. However, corrosion protection using paint requires a drying process after application, which is time-consuming and reduces work efficiency, for example, when performing localized repairs on civil engineering and construction applications such as bridges. Furthermore, corrosion protection using paint is prone to uneven work.

[0003] In view of the above circumstances, efforts have been made to improve workability by imparting sacrificial corrosion protection to adhesive tapes and the like. For example, Patent Document 1 discloses a corrosion prevention method in which a corrosion protection member is attached to the outer surface of a metal pipe, the corrosion protection member being a laminate consisting of a conductive adhesive layer containing zinc powder, a zinc plate, a resin film, and a stainless steel plate. In this corrosion prevention method, the zinc powder contained in the adhesive layer and the zinc plate act as sacrificial anodes, preventing corrosion of the metal pipe.

[0004] Patent Document 2 discloses a corrosion-resistant member that contains a conductive material and has a conductive adhesive layer with a resistance value of a certain value or less. Use of this corrosion-resistant member can improve both adhesive properties and sacrificial corrosion protection. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-242982 [Patent Document 2] Japanese Patent Application Publication No. 2019-127606 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the corrosion-resistant member described in Patent Document 1 cannot conform to the shape of an adherend having a complex shape, and therefore the corrosion-resistant member cannot be sufficiently adhered to an adherend having a complex shape, and the corrosion-resistant member cannot fully exhibit its corrosion-resistant properties. Furthermore, Patent Document 2 also discloses a single-sided pressure-sensitive adhesive tape having a substrate as a corrosion-resistant member, but the flexibility of the substrate has not been sufficiently considered, which may result in the tape being unable to conform to the shape of an adherend having a complex shape, and thus failing to fully exhibit corrosion resistance. Therefore, an object of the present invention is to provide an anticorrosive pressure-sensitive adhesive tape that has excellent anticorrosive properties for adherends having complex shapes. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by an anticorrosion adhesive tape comprising a film having a certain level of elongation at break at 100°C or more and an adhesive layer provided on at least one side of the film, which does not develop rust in a cyclic corrosion test in accordance with Cycle D of JIS K5600-7-9 and has a certain level of adhesive strength after the cyclic corrosion test, and have completed the present invention as described below. That is, the present invention provides the following [1] to [7]. [1] A corrosion-preventive adhesive tape comprising a film having an elongation at break of 150% or more at 100°C and an adhesive layer provided on at least one side of the film, which does not rust in a cyclic corrosion test in accordance with Cycle D of JIS K5600-7-9, and has an adhesive strength of 20 N / 25 mm or more after the cyclic corrosion test. [2] The anticorrosion adhesive tape according to [1] above, wherein the thickness of the adhesive layer is 100 μm or more. [3] The anticorrosion adhesive tape according to [1] or [2] above, wherein the adhesive layer contains a metal having a lower potential than iron. [4] The anticorrosion adhesive tape according to [3] above, wherein the metal having a lower potential than iron is zinc. [5] The anticorrosion adhesive tape according to [3] or [4] above, wherein the adhesive layer contains a conductive material other than the metal having a lower potential than iron. [6] The anticorrosion adhesive tape according to [5] above, wherein the conductive material is carbon nanotubes. [7] The anticorrosion adhesive tape according to any one of the above [1] to [6], wherein the adhesive layer is formed from an acrylic adhesive. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an anticorrosive pressure-sensitive adhesive tape that has excellent anticorrosive properties for adherends having complex shapes. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of an anticorrosion adhesive tape according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of an anticorrosive pressure-sensitive adhesive tape according to one embodiment of the present invention, in which the pressure-sensitive adhesive layer contains a sacrificial anticorrosive metal. [Figure 3] FIG. 3 is a cross-sectional view of an anticorrosive pressure-sensitive adhesive tape according to one embodiment of the present invention, in which the pressure-sensitive adhesive layer contains a conductive material in addition to a sacrificial anticorrosive metal. [Figure 4] FIG. 4 is a cross-sectional view of a modified example of the anticorrosion adhesive tape according to one embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view of a modified example of the anticorrosion adhesive tape according to one embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view of a modified example of the anticorrosion adhesive tape according to one embodiment of the present invention. [Figure 7] 7(a) to 7(c) are diagrams for explaining a test method for convex portion followability. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Anti-corrosion adhesive tape] An anticorrosion adhesive tape according to one embodiment of the present invention will be described with reference to Fig. 1. An anticorrosion adhesive tape 10 according to one embodiment of the present invention comprises a film 11 having an elongation at break of 150% or more at 100°C, and an adhesive layer 12 provided on at least one surface 11a of the film 11. The adhesive tape does not rust in a cyclic corrosion test in accordance with Cycle D of JIS K5600-7-9, and has an adhesive strength of 20 N / 25 mm or more after the cyclic corrosion test.

[0011] <Film elongation at break at 100°C> In the anticorrosion adhesive tape 10 of one embodiment of the present invention, the film 11 has an elongation at break of 150% or more at 100°C. If the elongation at break of the film 11 at 100°C is less than 150%, when the anticorrosion adhesive tape 10 is adhered to an adherend having a complex shape, the anticorrosion adhesive tape 10 may not adhere well to the adherend. This may result in insufficient corrosion protection of the anticorrosion adhesive tape 10 against an adherend having a complex shape. From this perspective, the elongation at break of the film 11 at 100°C is preferably 200% or more, more preferably 300% or more, even more preferably 400% or more, and even more preferably 500% or more. The upper limit of the range of the elongation at break of the film 11 at 100°C is not particularly limited, but the elongation at break of the film 11 at 100°C is, for example, 1000% or less, preferably 800% or less. An example of an adherend having a complex shape is a remnant reinforcing bar that remains on the surface of a steel material after the reinforcing bar is cut off at a construction site.

[0012] Examples of films having an elongation at break of 150% or more at 100°C include olefin-based resin films, specifically polypropylene-based resin films such as unstretched polypropylene (CPP) film and oriented polypropylene (OPP) film, and polyethylene-based resin films such as high-density polyethylene (HDPE) film, low-density polyethylene (LDPE) film, and linear low-density polyethylene (LLDPE) film. In addition to olefin-based resin films, examples include polyester films such as fluororesin films and polyethylene terephthalate-based resin films.

[0013] <Film thickness> The thickness of the film 11 is not particularly limited, but is, for example, 10 to 100 μm, preferably 25 to 80 μm, and more preferably 50 to 75 μm. By making it 50 μm or more, it can properly function as a support. Furthermore, by making it 75 μm or less, it can improve adhesion to adherends with complex shapes.

[0014] <Presence or absence of rust in cyclic corrosion tests> The anticorrosion adhesive tape 10 of one embodiment of the present invention does not rust in accordance with JIS K5600-7-9 (General testing methods for paints - Part 7: Long-term durability of coating films - Section 9: Cyclic corrosion test method - Salt spray / dry / wet, Cycle D). Therefore, the anticorrosion adhesive tape 10 of one embodiment of the present invention has excellent corrosion prevention properties. If rust occurs in the cyclic corrosion test, the corrosion prevention properties of the anticorrosion adhesive tape 10 will be insufficient. The occurrence of rust can be suppressed by adjusting the composition, thickness, etc. of the adhesive layer 12 provided in the anticorrosion adhesive tape 10.

[0015] The occurrence of rust in the cyclic corrosion test is confirmed as follows. A test piece is prepared by attaching the anticorrosion adhesive tape 10 of one embodiment of the present invention to a test plate specified in JIS K5600-7-9. The anticorrosion adhesive tape 10 is attached so that the adhesive layer 12 comes into contact with the surface of the test plate. The size of the anticorrosion adhesive tape 10 is 150 mm in length and 70 mm in width. Next, a notch is made on the test piece from the side of the corrosion-preventive adhesive tape 10. The notches are made by making two linear notches that cross each other (i.e., making notches in the shape of an X). Each notch is 70 mm long, and the two notches intersect at a 90° angle. The notches are made using a single-blade notching tool so that they reach the test plate, which is the base material, as specified in JIS K5600-7-9. The test specimen with the notch is then subjected to a salt spray test based on cycle D of JIS K5600-7-9, Appendix 1. The test is carried out for 28 cycles (total of 168 hours). After the salt spray test, the test piece is observed to check for the presence or absence of rust at the cut area.

[0016] <Adhesion strength after cyclic corrosion test> The anticorrosion adhesive tape 10 according to one embodiment of the present invention has an adhesive strength of 20 N / 25 mm or more after a cyclic corrosion test. If the adhesive strength is less than 20 N / 25 mm, the long-term adhesive strength will be insufficient, and the anticorrosion adhesive tape 10 will be more likely to peel off from an adherend such as a steel material, resulting in reduced corrosion prevention. From the viewpoint of increasing the adhesive strength and improving corrosion resistance, the adhesive strength after the cyclic corrosion test is preferably 25 N / 25 mm or more, more preferably 30 N / 25 mm or more, and even more preferably 40 N / 25 mm or more. The higher the adhesive strength, the better, but in practice it is 200 N / 25 mm or less.

[0017] The adhesive strength of the anticorrosion adhesive tape 10 after the cyclic corrosion test is measured as follows. The anticorrosion adhesive tape of the present invention is applied to a stainless steel plate (SUS plate) to prepare a sample for adhesive strength evaluation. At this time, the adhesive layer of the anticorrosion adhesive tape is applied so as to come into contact with the surface of the SUS plate to prepare a sample for adhesive strength evaluation. The size of the anticorrosion adhesive tape 10 is 100 mm in length and 25 mm in width. Using the adhesive strength evaluation sample, a salt spray test is carried out based on cycle D of JIS K5600-7-9, Appendix 1. The test is carried out for 28 cycles (total of 168 hours). After the salt spray test, the adhesive strength evaluation samples are subjected to a peel test of anticorrosion adhesive tape to measure their adhesive strength. The peel test is carried out using a tensile tester at a peel angle of 180° and a speed of 300 mm / min, and the average value of the detected load (N) is taken as the adhesive strength.

[0018] <Adhesive layer> The anticorrosion adhesive tape 10 of one embodiment of the present invention includes an adhesive layer 12. The adhesive layer 12 will be described below.

[0019] The pressure-sensitive adhesive layer 12 does not need to contain a sacrificial anticorrosive metal, which will be described later. In this case, the adhesive strength of the anticorrosive pressure-sensitive adhesive tape 10 is maintained at a high level compared to when a sacrificial anticorrosive metal is contained, thereby improving adhesion to the adherend, thereby blocking water and oxygen and making it easier to improve corrosion prevention.

[0020] (a metal with a lower potential than iron) 2, the pressure-sensitive adhesive layer 12 may contain a metal 13 having a lower potential than iron. By containing the metal 13 having a lower potential than iron (hereinafter also referred to as "sacrificial corrosion protection metal"), the pressure-sensitive adhesive layer 12 has sacrificial corrosion protection properties, thereby enhancing the corrosion protection of the corrosion-protective pressure-sensitive adhesive tape 10. The sacrificial corrosion protection metal 13 is dispersed in the pressure-sensitive adhesive that constitutes the pressure-sensitive adhesive layer 12.

[0021] Examples of the sacrificial corrosion protection metal 13 include cadmium, chromium, zinc, manganese, and aluminum, among which zinc and aluminum are preferred, with zinc being particularly preferred. Use of zinc provides excellent sacrificial corrosion protection.

[0022] The sacrificial corrosion protection metal 13 may be dispersed in the pressure-sensitive adhesive as a filler in any form, such as a particle form, a scale form, or a spindle form, but is preferably in a particle form. By making the sacrificial corrosion protection metal 13 in a particle form, it becomes easier to disperse in the pressure-sensitive adhesive layer 12 without substantially reducing the adhesiveness of the pressure-sensitive adhesive layer 12. 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.

[0023] The content of the sacrificial corrosion protection metal 13 in the adhesive layer is, for example, 0.5 to 20 mass %, preferably 1 to 15 mass %, and more preferably 2 to 12 mass %, based on the total mass of the adhesive layer. If the content of the sacrificial corrosion protection metal 13 is equal to or greater than these lower limit values, the sacrificial corrosion protection property is enhanced, thereby improving the corrosion prevention performance, and if it is equal to or less than these upper limit values, the adhesive strength is increased.

[0024] (Conductive materials) 3, the pressure-sensitive adhesive layer 12 preferably further contains, in addition to the sacrificial corrosion-protective metal 13, a conductive material 14 other than the sacrificial corrosion-protective metal. When the conductive material 14 is contained, electrons released when the sacrificial corrosion-protective metal 13 is ionized can be more easily transferred to the adherend, which further improves the sacrificial corrosion protection properties. The conductive material 14 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 conductive materials, carbon-based materials are preferred, and carbon nanotubes are more preferred.

[0025] (carbon nanotubes) As in the anticorrosion adhesive tape 10B shown in Fig. 3, the adhesive layer 12 preferably contains carbon nanotubes 14 in addition to the sacrificial anticorrosion metal 13. The inclusion of carbon nanotubes 14 improves the sacrificial anticorrosion properties of the adhesive layer and maintains high adhesive strength, making it easier to obtain an anticorrosion adhesive tape 10B that combines high adhesive strength with excellent sacrificial anticorrosion properties. This is presumably because, although carbon nanotubes 14 are a conductive material, a smaller amount is required to exhibit a certain level of sacrificial anticorrosion properties compared to other types of conductive materials, and therefore the degree of decrease in adhesive strength is small.

[0026] Carbon nanotubes 14 are tubular materials made from carbon. Carbon nanotubes 14 have excellent electrical properties, and when combined with resin or other materials, they can be used to form highly conductive sheets. Carbon nanotubes are substances with a structure in which graphite sheets with a hexagonal mesh-like arrangement of carbon atoms are rolled up into a cylinder; those rolled up in one layer are called single-wall carbon nanotubes, and those rolled up in multiple layers are called multi-wall carbon nanotubes. In the corrosion prevention adhesive tape 10B of one embodiment of the present invention, the type of carbon nanotubes 14 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 also be used.

[0027] The carbon nanotubes 14 preferably have an average diameter of 1 to 100 nm, more preferably 2 to 15 nm. The carbon nanotubes 14 preferably have an average length of 0.1 to 1000 μm, more preferably 10 to 500 μm. The carbon nanotubes 14 preferably have an aspect ratio (average length / average diameter) of 10 to 100,000, more preferably 500 to 30,000. The diameter of carbon nanotubes 14 refers to the outer diameter in the case of single-walled carbon nanotubes, and the outer diameter of the outermost tube in the case of multi-walled carbon nanotubes. The diameter and length of carbon nanotubes 14 may be measured, for example, from an image obtained by observation with a TEM (transmission electron microscope), and the average diameter and average length may be calculated as the arithmetic mean of any 50 nanotubes.

[0028] From the viewpoint of the sacrificial corrosion protection and adhesive strength of the adhesive layer 12, the content of the conductive material 14 in the adhesive layer 12 is preferably 0.005 to 10 mass %, more preferably 0.005 to 5 mass %, and even more preferably 0.006 to 3 mass %, based on the total amount of the adhesive layer.

[0029] When the conductive material 14 is carbon nanotubes, the content of the carbon nanotubes 14 in the adhesive layer 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 mass of the adhesive layer. When the content of carbon nanotubes 14 is equal to or greater than these lower limit values, the sacrificial corrosion resistance is likely to be enhanced, and when the content of carbon nanotubes is equal to or less than these upper limit values, the adhesive strength is likely to be improved.

[0030] (adhesive) The adhesive layer 12 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, the pressure-sensitive adhesive layer 12 is preferably formed from an acrylic pressure-sensitive adhesive.

[0031] (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 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.

[0032] ((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 increase adhesive strength, and it is also easy to adjust the storage modulus at 23°C of the pressure-sensitive adhesive described below to a predetermined range.

[0033] 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.

[0034] The structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) constitutes the main component of the pressure-sensitive adhesive layer 12, and its content is generally 30 mass % or more, preferably 50 mass % or more, and more preferably 70 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) in this way makes it possible to impart a desired adhesive strength to the pressure-sensitive adhesive layer 12. Furthermore, the content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) is, for example, 97 mass % or less, preferably 95 mass % or less, and more preferably 90 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 12 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 therefore be expressed interchangeably. The same applies to components other than component (A), such as components (B) and (C) described below.

[0035] (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.

[0036] 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 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, the adhesive strength of the corrosion prevention pressure-sensitive adhesive tape can be easily improved.

[0037] (olefin polymer (C)) The polymerizable monomer preferably further contains an olefin polymer (C) having a polymerizable bond at one end. Use of such an olefin polymer (C) makes it easier to improve the adhesive strength of the anticorrosion adhesive tape. 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.

[0038] 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.

[0039] 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 12 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).

[0040] (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 pressure-sensitive adhesive layer 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).

[0041] (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).

[0042] (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).

[0043] (Other ingredients) The acrylic adhesive used in the adhesive layer 12 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.

[0044] (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, and optionally a sacrificial corrosion-protective metal and a conductive material, 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 corrosion protection metal and a conductive material which are blended as necessary, and a tackifier resin, fine particles, and other components which are blended as necessary 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.

[0045] (rubber adhesive) Next, the rubber-based adhesive used in the adhesive layer 12 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.

[0046] 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).

[0047] 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.

[0048] 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.

[0049] (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.

[0050] (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.

[0051] (storage modulus G') The pressure-sensitive adhesive layer 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 is within this range, when the pressure-sensitive adhesive layer is damaged by an external impact or the like, the force with which the damaged area returns to its original state (hereinafter also referred to as self-repairing force) becomes strong. As a result, rust generation is suppressed and corrosion prevention performance is improved. The storage modulus G' can be adjusted by appropriately changing the materials constituting the pressure-sensitive adhesive layer, the curing conditions of the pressure-sensitive adhesive layer, etc. The storage modulus G' of the pressure-sensitive adhesive layer at 23° C. is more preferably 200,000 to 800,000 Pa, and even more preferably 300,000 to 600,000 Pa, from the viewpoint of increasing the self-repairing ability and improving the anticorrosion performance. 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.

[0052] (Thickness) The thickness of the pressure-sensitive adhesive layer 12 is preferably 100 μm or more. By making the thickness 100 μm or more, the self-repairing ability and the like are enhanced, and the corrosion resistance of the anticorrosion pressure-sensitive adhesive tape can be improved. From this viewpoint, the thickness of the pressure-sensitive adhesive layer is more preferably 200 μm or more, even more preferably 300 μm or more, and even more preferably 500 μm or more. There is no particular upper limit to the thickness of the pressure-sensitive adhesive layer, but from the viewpoint of obtaining an effect of improving the corrosion resistance performance according to the thickness, it is, for example, 3000 μm.

[0053] [Applications for anti-corrosion adhesive tape] The anticorrosion adhesive tape of one embodiment of the present invention is applied to various adherends and used to protect the adherends from corrosion. Because the anticorrosion adhesive tape of one embodiment of the present invention has excellent adhesive strength and corrosion prevention properties, it is preferably applied to the surface of an adherend made of various metal materials. The metal material is preferably a metal material containing at least one selected from the group consisting of iron and iron-containing alloys. Specific examples of iron-containing alloys 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.

[0054] The anticorrosion adhesive tape according to one embodiment of the present invention is preferably used on an adherend having an uneven surface, since the anticorrosion adhesive tape according to the present invention can be applied to an adherend even if the adherend has an uneven surface, conforming to the unevenness, and is also excellent in anticorrosion properties for an adherend having an uneven surface. Furthermore, the anticorrosion pressure-sensitive adhesive tape according to one embodiment of the present invention is preferably applied to an adherend, and then pressed onto various adherends while being heated, for example, to 90 to 150°C, preferably 90 to 130°C. By pressing onto the adherend while being heated, the tape can be adhered with high adhesion even to adherends having irregularities, ensuring high corrosion prevention. The pressure-sensitive adhesive tape may be heated using a known heating device such as an industrial dryer.

[0055] The anticorrosion pressure-sensitive adhesive tape according to one embodiment of the present invention is preferably used for repair, which refers to the application of anticorrosion treatment to metal materials such as steel materials that constitute existing structures such as bridges, steel towers, viaducts, tanks, plants, and bridge piers. Specifically, the above-mentioned existing structures may have areas where the anticorrosive paint has peeled off, or may have cut surfaces exposed when steel materials or the like are cut during repair work on the structures. The anticorrosive pressure-sensitive adhesive tape of the present invention may be applied to areas where the anticorrosive paint has peeled off or to cut surfaces where no anticorrosive paint has been applied. The anticorrosion adhesive tape can protect the adherend from corrosion by being applied to the adherend and, if necessary, heated and pressed, so that anticorrosion treatment can be completed in a short time and it is suitable for use in repairs. In addition, the substrate to be repaired often has unevenness, for example, due to fine irregularities (e.g., remaining rebar) on the cut surface after cutting.However, the corrosion-resistant adhesive tape of the present invention can maintain high corrosion resistance even when the substrate has unevenness, making it suitable for repairs in this respect as well.

[0056] [Modification of anticorrosion adhesive tape] The anticorrosion adhesive tape 10 of the present invention can be modified as follows. (Variation 1) As shown in FIG. 4, a corrosion prevention adhesive tape 10C may include a film 11 having an elongation at break of 150% or more at 100°C and adhesive layers 12 provided on both surfaces 11a, 11b of the film 11. This allows for a double-sided adhesive tape. At least one of the adhesive layers 12, 12 may have the configuration described above. The adhesive layers 12, 12 may have the same configuration, but they do not have to have the same configuration. For example, one adhesive layer may contain a metal with a lower potential than iron and a conductive material, while the other adhesive layer does not contain these.

[0057] (Variation 2) As in the anticorrosion adhesive tape 10D shown in Fig. 5, a substrate 15 other than the film 11 may be further provided on at least one surface 11b of the film 11. This allows the film 11 to be protected by the substrate 12. Note that the substrate 15 is preferably one that does not hinder the elongation of the film 11 as much as possible when the film 11 is stretched while being heated. Furthermore, although not shown, the anticorrosion adhesive tape 10D may be a double-sided adhesive tape by providing an additional adhesive layer on the surface of the substrate 15 opposite to the film side. The substrate 15 may be bonded directly to the film 11, or may be bonded to the film 11 via an adhesive layer or a pressure-sensitive adhesive layer (not shown).

[0058] Examples of the substrate 15 include nonwoven fabric, paper such as Japanese paper, woven fabric made of natural or synthetic fibers, resin films such as acrylic resin film, fluorine-based resin film, propylene resin film, and polyethylene resin film, and flat yarn cloth. Examples of propylene resin films include unstretched polypropylene (CPP) film and oriented polypropylene (OPP) film. Examples of polyethylene films include high-density polyethylene film and low-density polyethylene film. Flat yarn cloth is made by arranging flat yarns made of synthetic resin such as polyolefin resin in a biaxial, triaxial, or tetraaxial grid pattern and bonding the intersections. The thickness of the substrate 15 is not particularly limited, but is, for example, 10 to 200 μm, and preferably 20 to 100 μm.

[0059] (Variation 3) As described above, the adhesive layer 12 of the anticorrosion adhesive tape 10 according to one embodiment of the present invention may not contain a metal having a lower potential than iron. In this case, to enhance the corrosion resistance of the anticorrosion adhesive tape 10, as shown in FIG. 6 , the anticorrosion adhesive tape 10E further includes a metal layer 16 between the film 11 and the adhesive layer 12, and the metal layer 16 is preferably a layer of a metal having a lower potential than iron. While the metal having a lower potential than iron may be any of the metals listed above without any particular limitation, the metal layer 16 is preferably a layer of zinc. Specifically, the metal layer 16 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 12. Alternatively, the metal layer 16 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.

[0060] The metal layer 16 is preferably formed directly on the adhesive layer 12. This allows the metal constituting the metal layer 16, which has a lower potential than iron, to come into contact with the adhesive layer 12. When a metal with a lower potential than iron comes into contact with the adhesive layer 12, electrons released upon ionization can easily migrate to the adhesive layer 12, thereby improving the corrosion resistance of the corrosion-resistant adhesive tape 10E. Although not shown, the adhesive layer 12 may also contain a conductive material 14 other than a metal with a lower potential than iron, from the perspective of the corrosion resistance of the corrosion-resistant adhesive tape 10E. In this case, the film 11 may be bonded directly to the metal layer 16 or may be bonded to the metal layer 16 via an adhesive or pressure-sensitive adhesive layer (not shown).

[0061] The thickness of the metal layer 16 is preferably 2.5 μm or more. When the thickness of the metal layer 16 is 2.5 μm or more, the metal layer 16 can sufficiently supply electrons due to ionization of the metal in the metal layer 16, thereby maintaining sufficient corrosion resistance of the anticorrosion adhesive tape 10E. From the viewpoint of improving the corrosion resistance of the anticorrosion adhesive tape 10E, the thickness of the metal layer 16 is more preferably 5 μm or more. Furthermore, from the viewpoint of minimizing the inhibition of elongation of the film 11 when the film 11 is stretched while being heated, the thickness of the metal layer 16 is preferably 200 μm or less, more preferably 100 μm or less.

[0062] The anticorrosion adhesive tape of one embodiment 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 an adherend. 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.

[0063] The anticorrosion adhesive tapes 10, 10A to 10E of one embodiment of the present invention are merely examples of the anticorrosion adhesive tapes of the present invention, and therefore the anticorrosion adhesive tapes of the present invention are not limited to the anticorrosion adhesive tapes 10, 10A to 10E of one embodiment of the present invention. [Example]

[0064] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0065] <Evaluation method> In the examples and comparative examples, the anticorrosion adhesive tapes were evaluated by the following evaluation methods. (Elongation at break at 100°C) The films used to prepare the anticorrosion adhesive tapes of each Example and Comparative Example were each prepared into samples in accordance with JIS K7127. After heating to 100°C, tensile tests were performed in both the MD and TD directions using a Tensilon tensile testing machine manufactured by Orientec Co., Ltd., and the elongation at break was calculated using the following formula. Elongation at break (%) = (L-L0) / L0 x 100 where L is the length of the sample at break and L0 is the length of the sample before the tensile test. The smaller of the calculated elongations at break in the MD and TD directions was taken as the elongation at break of the film.

[0066] (Storage modulus at 23°C) The storage modulus at 23°C of the adhesive layer of the anticorrosion adhesive tape was calculated by measuring the dynamic viscoelastic 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.

[0067] (Whether or not rust occurs in cyclic corrosion tests) As described in the specification, the presence or absence of rust in the notched area was visually confirmed 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).

[0068] (Adhesive strength) 1. Sample Preparation An anticorrosion adhesive tape (25 mm wide, 100 mm long) from each example and comparative example was applied to a SUS plate (50 mm wide, 125 mm long), and a roller weighing 2 kg was run back and forth twice on the applied anticorrosion adhesive tape at a speed of 10±0.5 mm / s to prepare a sample for adhesive strength evaluation. The initial adhesive strength (adhesive strength before testing) was measured using this adhesive strength evaluation sample. In addition, a salt spray test was conducted using a separate adhesive strength evaluation sample prepared in the same manner, based on cycle D of Appendix 1 of JIS K5600-7-9. The test was conducted for 28 cycles (total of 168 hours). The adhesive strength of the adhesive strength evaluation sample after the salt spray test was then measured. 2. Adhesion measurement The adhesive strength was measured as follows. Each adhesive strength evaluation sample was fixed to the chuck of a tensile testing machine (Tensilon Universal Material Testing Machine, manufactured by A&D Co., Ltd.). The anticorrosion adhesive tape was then pulled for 60 mm or more at a peel angle of 180° and a speed of 300 mm / min, and the average value of the load (N) detected by the load cell was recorded and used as the adhesive strength.

[0069] (Convex part tracking ability) The method for testing the convex portion followability will be described with reference to FIG. A tester 20 was prepared, which had a square pillar 21 measuring 10 mm × 10 mm × 10 mm attached to the center of a stainless steel plate. As shown in FIG. 7( a), the square pillar 21 of the tester 20 was covered with the anticorrosive adhesive tape 10 of each example and comparative example. The adhesive layer side of the anticorrosive adhesive tape 10 was the side that contacted the tester 20. The anticorrosive adhesive tape 10 was then heated to 100°C, and as shown in FIG. 7( b), the heated anticorrosive adhesive tape 10 was adhered to the upper surface of the square pillar 21. The anticorrosive adhesive tape 10 was then pressed (see arrow 30) to gradually adhere the anticorrosive adhesive tape 10 to the side of the square pillar 21 from top to bottom. The height (h) (see FIG. 7( c)) of the part of the side of the square pillar 21 where the anticorrosive adhesive tape 10 could not be adhered (lifted part) was measured and evaluated according to the following criteria. The smaller the height (h) of the floating portion, the better the anticorrosion adhesive tape's ability to conform to the convex portions. ○ The height of the floating part is less than 0.5 mm × The height of the floating part is 0.5 mm or more

[0070] (Practical evaluation of peeling) Anticorrosion adhesive tapes (25 mm wide, 125 mm long) from each example and comparative example were attached to a stainless steel plate (50 mm wide, 125 mm long) and cured at 23°C for 3 days to prepare samples for peeling evaluation. Water was sprayed for 5 minutes at a water pressure of 8 MPa toward the longitudinal end side of the anticorrosion adhesive tape from a spraying position diagonally above the anticorrosion adhesive tape in the peeling evaluation sample. The water spraying position was set so that the angle between the SUS plate and a line connecting the spraying position and the center of the end of the anticorrosion adhesive tape was 30°, and the position was directly above a point 5 cm horizontally away from the center of the end of the anticorrosion adhesive tape. The distance that the anticorrosive adhesive tape peeled off after the water spraying was measured and evaluated according to the following criteria. ◎ Peeling distance is 0mm or more and less than 15mm ○ Peeling distance is 15mm or more but less than 25mm × Peeling distance is 25mm or more

[0071] [Example 1] A pressure-sensitive adhesive composition 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 Film 1, and the pressure-sensitive adhesive composition was applied to the release-treated surface of the release sheet. Next, a 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. 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 is 5 mW / cm 2 The lamp intensity of the chemical lamp was adjusted so that the release sheet side was irradiated with ultraviolet light for 15 minutes, resulting in an anticorrosion adhesive tape comprising a film and an adhesive layer provided on one side of the film, with the release sheet attached to the adhesive layer. The adhesive layer had a thickness of 600 μm. The release sheet was peeled off from the anticorrosion adhesive tape, and various evaluations were performed. The results are shown in Table 1.

[0072] [Examples 2 to 3, Comparative Examples 1 to 4] An anticorrosion adhesive tape was obtained in the same manner as in Example 1, except that a pressure-sensitive adhesive composition was prepared according to the formulation shown in Table 1, the thickness was adjusted as shown in Table 1, and a film shown in Table 1 was used. The results are shown in Table 1.

[0073] [Table 1]

[0074] 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 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 Zinc particles: Sakai Chemical Industry Co., Ltd., product name "Zinc powder #40", average particle size: 50 μm Carbon nanotubes (CNT): manufactured by JEIO, product name "JENOTUBE8A", average diameter 6-9 nm, average length 100-200 μm Carbon-based material: Artificial graphite powder, Oriental Sangyo Co., Ltd., product name "AT-NO.15S", average particle size 13 μm Crosslinking agent: Product name "TEAI-1000", manufactured by Nippon Soda Co., Ltd. Polymerization initiator: 2,2-dimethoxy-2-phenylacetophenone Film 1: CPP film Film 2: Low-density polyethylene (LDPE) film Film 3: Acrylic resin film, manufactured by Mitsubishi Chemical Corporation, product name "Acriplene MBS121E" Film 4: Ionomer resin film in which ethylene-methacrylic acid copolymer molecules are cross-linked with zinc ions, manufactured by Mitsui Dow Polychemicals Co., Ltd., product name "Himilan 1855"

[0075] The anticorrosion adhesive tapes of Examples 1 to 3 have excellent convex-conforming ability and are difficult to peel off. Therefore, it is thought that the anticorrosion adhesive tapes of Examples 1 to 3 have excellent anticorrosion properties for adherends having complex shapes. On the other hand, the anticorrosion adhesive tapes of Comparative Examples 1 and 2 are difficult to peel off, but have poor convex-conforming ability. Furthermore, the anticorrosion adhesive tapes of Comparative Examples 3 and 4 have good convex-conforming ability but are easy to peel off. Therefore, it is thought that the anticorrosion adhesive tapes of Comparative Examples 1 to 4 cannot adhere sufficiently to adherends having complex shapes, and therefore have inferior anticorrosion properties for adherends having complex shapes compared to the anticorrosion adhesive tapes of Examples 1 to 3. [Explanation of symbols]

[0076] 10 Anti-corrosion adhesive tape 11 Film 12 Adhesive layer 13 Metals with a lower potential than iron 14 Conductive materials (carbon nanotubes) 15 Base material 16 metal layer

Claims

1. A corrosion-preventive adhesive tape comprising a film having an elongation at break of 300% or more at 100°C and an adhesive layer provided on at least one surface of the film, wherein the tape does not develop rust in a cyclic corrosion test in accordance with Cycle D of JIS K5600-7-9, has an adhesive strength of 20 N / 25 mm or more after the cyclic corrosion test, and has a storage modulus G' of 50,000 to 1,000,000 Pa at 23°C.

2. The anticorrosion adhesive tape according to claim 1 , wherein the thickness of the adhesive layer is 100 μm or more.

3. The corrosion-preventive adhesive tape according to claim 1 or 2, wherein the adhesive layer contains a metal having a lower potential than iron.

4. 4. The corrosion-preventive adhesive tape according to claim 3, wherein the metal having a lower potential than iron is zinc.

5. The corrosion-preventive adhesive tape according to claim 3 or 4, wherein the adhesive layer contains a conductive material other than the metal having a lower potential than iron.

6. The corrosion-preventing adhesive tape according to claim 5 , wherein the conductive material is a carbon nanotube.

7. The anticorrosion adhesive tape according to any one of claims 1 to 6, wherein the adhesive layer is formed from an acrylic adhesive.

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