JP2022136763A - Anticorrosive adhesive tape - Google Patents

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 The present invention relates to an anticorrosion pressure-sensitive adhesive tape.

Anticorrosive paints containing a large amount of zinc are widely used to prevent corrosion of iron or iron-containing alloys such as steel. Zinc is known to have high anticorrosion properties because it is a metal with a lower potential than iron and has a sacrificial anticorrosion action. However, anticorrosion with paint requires a drying process after application, and the work takes a long time. In addition, anti-corrosion with paint tends to cause unevenness in work.

In view of the above situation, efforts have been made to improve workability by imparting sacrificial anti-corrosion properties to adhesive tapes and the like. For example, Patent Document 1 discloses a corrosion prevention method in which a corrosion prevention member, which is a laminate including a conductive adhesive layer containing zinc powder, a zinc plate, a resin film, and a stainless steel plate, is attached to the outer peripheral surface of a metal pipe. It is In this anti-corrosion method, the zinc powder contained in the adhesive layer and the zinc plate act as a sacrificial anode to prevent corrosion of metal pipes.

Patent Document 2 discloses an anti-corrosion member including a conductive pressure-sensitive adhesive layer containing a conductive material and having a resistance value of a certain value or less. By using the anti-corrosion member, both adhesive physical properties and sacrificial anti-corrosion properties can be improved.

JP-A-9-242982 JP 2019-127606 A

However, since the anticorrosion member described in Patent Document 1 cannot follow the shape of the adherend having a complicated shape, the anticorrosion member cannot be sufficiently adhered to the adherend having a complicated shape. , the anti-corrosion property of the anti-corrosion member cannot be sufficiently exhibited.
Further, the anticorrosive member of Patent Document 2 also discloses a single-sided pressure-sensitive adhesive tape having a base material, but the flexibility of the base material is not sufficiently studied. Therefore, it may not be able to follow the shape of an adherend having a complicated shape, and may not exhibit its anticorrosion property sufficiently.
Accordingly, an object of the present invention is to provide an anticorrosion pressure-sensitive adhesive tape that exhibits excellent anticorrosion properties for an adherend having a complicated shape.

As a result of intensive studies, the present inventors have found that a film having a certain elongation at break at 100 ° C. or more and a pressure-sensitive adhesive layer provided on at least one surface of the film are provided. We have found that the above problems can be solved by an anti-corrosion adhesive tape that does not generate rust in a cycle corrosion test based on cycle D and has a certain or more adhesive strength after the cycle corrosion test, and has completed the following invention. rice field.
That is, the present invention provides the following [1] to [7].
[1] A cycle comprising a film having an elongation at break of 150% or more at 100° C. and an adhesive layer provided on at least one surface of the film, and conforming to cycle D in JIS K5600-7-9. An anticorrosion pressure-sensitive adhesive tape that does not rust in a corrosion test and has an adhesive strength of 20 N/25 mm or more after a cyclic corrosion test.
[2] The anticorrosion pressure-sensitive adhesive tape according to [1] above, wherein the pressure-sensitive adhesive layer has a thickness of 100 μm or more.
[3] The anticorrosion pressure-sensitive adhesive tape according to the above [1] or [2], wherein the pressure-sensitive adhesive layer contains a metal having a lower potential than iron.
[4] The anticorrosion pressure-sensitive adhesive tape according to [3] above, wherein the metal having a potential lower than that of iron is zinc.
[5] The anticorrosive pressure-sensitive adhesive tape according to [3] or [4] above, wherein the pressure-sensitive adhesive layer contains a conductive material other than a metal having a potential lower than that of iron.
[6] The anticorrosion pressure-sensitive adhesive tape according to [5] above, wherein the conductive material is a carbon nanotube.
[7] The anticorrosion pressure-sensitive adhesive tape according to any one of [1] to [6] above, wherein the pressure-sensitive adhesive layer is formed from an acrylic pressure-sensitive adhesive.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive tape for anticorrosion which has the anticorrosiveness excellent with respect to the to-be-adhered body which has a complicated shape can be provided.

FIG. 1 is a cross-sectional view of an anticorrosion pressure-sensitive adhesive tape according to one embodiment of the present invention. FIG. 2 is a cross-sectional view of an anticorrosion pressure-sensitive adhesive tape of one embodiment of the present invention in which the pressure-sensitive adhesive layer contains a sacrificial anticorrosion metal. FIG. 3 is a cross-sectional view of an anticorrosion 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 anticorrosion metal. FIG. 4 is a cross-sectional view of a modification of the anticorrosive pressure-sensitive adhesive tape of one embodiment of the present invention. FIG. 5 is a cross-sectional view of a modification of the anticorrosive pressure-sensitive adhesive tape of one embodiment of the present invention. FIG. 6 is a cross-sectional view of a modification of the anticorrosion pressure-sensitive adhesive tape of one embodiment of the present invention. FIGS. 7A to 7C are diagrams for explaining a method for testing conformability to convex portions.

[Anti-corrosion adhesive tape]
An anticorrosive pressure-sensitive adhesive tape according to one embodiment of the present invention will be described with reference to FIG. An anticorrosive adhesive tape 10 of one embodiment of the present invention includes 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 conforming to cycle D in JIS K5600-7-9, and has an adhesive strength of 20 N/25 mm or more after the cyclic corrosion test.

<Elongation at break at 100°C of film>
The elongation at break at 100° C. of the film 11 in the anticorrosive pressure-sensitive adhesive tape 10 of one embodiment of the present invention is 150% or more. If the elongation at break of the film 11 at 100° C. is less than 150%, when the anticorrosion pressure-sensitive adhesive tape 10 is adhered to an adherend having a complicated shape, the adhesion of the anticorrosion pressure-sensitive adhesive tape 10 to the adherend is insufficient. may be sufficient. As a result, the anticorrosiveness of the anticorrosive pressure-sensitive adhesive tape 10 to an adherend having a complicated shape may be insufficient. From such a viewpoint, the elongation at break at 100° C. of the film 11 is preferably 200% or more, more preferably 300% or more, still more preferably 400% or more, and even more preferably 500%. That's it. The upper limit of the range of the elongation at break at 100°C of the film 11 is not particularly limited, but the elongation at break at 100°C of the film 11 is, for example, 1000% or less, preferably 800% or less. . An adherend having a complicated shape is, for example, a residual reinforcing bar remaining on the surface of the steel material after removing the reinforcing bar at a construction site.

Films having an elongation at break of 150% or more at 100° C. include, for example, olefin-based resin films, specifically polypropylene-based resin films such as unstretched polypropylene (CPP) films and oriented polypropylene (OPP) films; Polyethylene-based resin films such as high-density polyethylene (HDPE) films, low-density polyethylene (LDPE) films, and linear low-density polyethylene (LLDPE) films are included. In addition to olefinic resin films, polyester films such as fluororesin films and polyethylene terephthalate resin films can also be used.

<Film thickness>
Although the thickness of the film 11 is not particularly limited, it is, for example, 10 to 100 μm, preferably 25 to 80 μm, more preferably 50 to 75 μm. By setting the thickness to 50 μm or more, the function as a support can be properly exhibited. Further, by setting the thickness to 75 μm or less, it is possible to enhance the adhesion to an adherend having a complicated shape.

<Presence or absence of rust in cyclic corrosion test>
The anticorrosive adhesive tape 10 of one embodiment of the present invention is JIS K5600-7-9 (General test method for paint-Part 7: Long-term durability of coating film-Section 9: Cyclic corrosion test method-Salt water spray/drying / Wet, no rust in cycle D). Therefore, the anti-corrosion pressure-sensitive adhesive tape 10 of one embodiment of the present invention is excellent in anti-corrosion properties. In the cyclic corrosion test, when rust occurs, the anticorrosion property of the adhesive tape 10 becomes insufficient. The occurrence of rust can be suppressed by adjusting the composition, thickness, etc. of the pressure-sensitive adhesive layer 12 included in the anti-corrosion pressure-sensitive adhesive tape 10 .

The presence or absence of rust generation in the cyclic corrosion test is confirmed as follows.
A test piece is prepared by attaching the anticorrosive adhesive tape 10 of one embodiment of the present invention to a test plate specified in JIS K5600-7-9. At this time, the surface of the test plate and the adhesive layer 12 of the anticorrosion adhesive tape 10 are adhered so as to be in contact with each other to prepare a test piece. The anticorrosive adhesive tape 10 has a length of 150 mm and a width of 70 mm.
Next, a cut is made on the test piece from the anticorrosive adhesive tape 10 side. A cut flaw is formed by making two linear flaws so as to cross each other (that is, make a flaw in the shape of an X mark). At this time, the length of one flaw is 70 mm, and the two flaws intersect at an angle of 90°. In addition, as specified in JIS K5600-7-9, the cut is applied using a single-blade cutting tool so as to reach the base test plate.
After that, using the test piece with the notch, a salt spray test is performed based on cycle D in Appendix 1 of JIS K5600-7-9. The test is performed for 28 cycles (total 168 hours).
Observe the test piece after the salt spray test to confirm the presence or absence of rust in the notch area.

<Adhesive strength after cyclic corrosion test>
The anticorrosive pressure-sensitive adhesive tape 10 of 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 anticorrosive pressure-sensitive adhesive tape 10 will easily peel off from an adherend such as a steel material, thereby deteriorating the anticorrosive properties.
From the viewpoint of increasing the adhesive strength and improving the 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 still more preferably 40 N/25 mm or more. The higher the adhesive strength, the better, but practically it is 200 N/25 mm or less.

The adhesive strength of the anticorrosion pressure-sensitive adhesive tape 10 after the cyclic corrosion test is measured as follows.
The anticorrosive adhesive tape of the present invention is attached to a stainless steel plate (SUS plate) to prepare a sample for adhesive strength evaluation. At this time, the surface of the SUS plate and the adhesive layer of the anticorrosion adhesive tape are attached so as to be in contact with each other to prepare a sample for adhesive strength evaluation. The anticorrosive adhesive tape 10 has a size of 100 mm in length and 25 mm in width.
A salt spray test is performed using the adhesive force evaluation sample based on Cycle D in Appendix 1 of JIS K5600-7-9. The test is performed for 28 cycles (total 168 hours).
After the salt spray test, the sample for adhesion evaluation is subjected to a peeling test of the anticorrosion adhesive tape to measure the adhesion. The peel test is performed using a tensile tester under the conditions of a peel angle of 180° and a speed of 300 mm/min.

<Adhesive layer>
An anti-corrosion pressure-sensitive adhesive tape 10 of one embodiment of the present invention comprises a pressure-sensitive adhesive layer 12 . The adhesive layer 12 will be described below.

The pressure-sensitive adhesive layer 12 may not contain a sacrificial anti-corrosion metal, which will be described later. In this case, as compared with the case where the sacrificial anti-corrosion metal is contained, the adhesive strength of the anti-corrosion pressure-sensitive adhesive tape 10 is maintained high, thereby improving the adhesion to the adherend, thereby blocking water and oxygen. , the corrosion resistance is likely to be improved.

(A metal with a lower potential than iron)
Like the anti-corrosion pressure-sensitive adhesive tape 10A shown in FIG. 2, the pressure-sensitive adhesive layer 12 may contain a metal 13 having a baser potential than iron. By containing the metal 13 (hereinafter also referred to as "sacrificial anti-corrosion metal") having a potential less base than that of iron, the adhesive tape 10 for anti-corrosion has sacrificial anti-corrosion properties, and the anti-corrosion properties of the adhesive tape 10 are enhanced. The sacrificial anti-corrosion metal 13 is dispersed in the adhesive constituting the adhesive layer 12 .

Examples of the sacrificial anticorrosion metal 13 include cadmium, chromium, zinc, manganese, and aluminum. Among these, zinc and aluminum are preferred, and zinc is particularly preferred. By using zinc, sacrificial corrosion resistance becomes excellent.

The sacrificial anti-corrosion metal 13 may be dispersed in the adhesive in any form as a filler, such as particle form, scale form, or spindle form, but is preferably in the form of particles. The sacrificial anti-corrosion metal 13 is in the form of particles, so that it can be easily dispersed in the pressure-sensitive adhesive layer 12 without substantially reducing the adhesiveness of the pressure-sensitive adhesive layer 12 .
In the present specification, the particle shape means that the ratio of the length in the long axis direction to the length in the short axis direction (aspect ratio) is small, for example, the aspect ratio is 3 or less, preferably 2 or less. The shape of the particles is not particularly limited, but may be spherical or amorphous such as powder. The particle size of the metal is, for example, 1 to 500 μm, preferably 1 to 200 μm. In addition, in this specification, the particle size means the average particle size measured by the laser diffraction method.

The content of the sacrificial anti-corrosion metal 13 in the adhesive layer is, for example, 0.5 to 20% by mass, preferably 1 to 15% by mass, more preferably 2 to 12% by mass, based on the total amount of the adhesive layer. %.
When the content of the sacrificial anti-corrosion metal 13 is at least these lower limits, the sacrificial anti-corrosion property increases, thereby improving the anti-corrosion performance.

(Conductive material)
Like the anti-corrosion adhesive tape 10B shown in FIG. 3, the adhesive layer 12 preferably further contains a conductive material 14 other than the sacrificial anti-corrosion metal 13 in addition to the sacrificial anti-corrosion metal 13 . When the conductive material 14 is contained, the electrons emitted when the sacrificial anti-corrosion metal 13 is ionized are easily transferred to the adherend, and the sacrificial anti-corrosion property is further improved.
Examples of the conductive material 14 include one or more selected from carbon-based materials, metal-based materials, metal oxide-based materials, ionic polymers, and conductive polymers.
Carbon-based materials include carbon black, graphite, graphene, carbon nanotubes, acetylene black, and the like. Examples of metal-based materials include metals whose potential is nobler than that of iron, such as gold, silver, copper, nickel, or alloys containing these, or iron. 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 (composite of polyethylenedioxythiophene and polystyrenesulfonic acid), polythiophene, polyaniline, poly(p-phenylene), polyfluorene, Examples include polycarbazole, polysilane, and derivatives thereof. Examples of ionic polymers include sodium polyacrylate and potassium polyacrylate.
These conductive materials may be used singly, or two or more of them may be used in combination.
Among the above conductive materials, carbon-based materials are preferred, and carbon nanotubes are more preferred.

(carbon nanotube)
Like the anticorrosion adhesive tape 10B shown in FIG. 3, the adhesive layer 12 more preferably contains carbon nanotubes 14 in addition to the sacrificial anticorrosion metal 13 . By containing the carbon nanotubes 14, the sacrificial anti-corrosion property of the adhesive layer can be improved and the adhesive strength can be maintained high, so it is easy to obtain the anti-corrosion adhesive tape 10B that has both high adhesive strength and excellent sacrificial anti-corrosion property. Become. This is because the carbon nanotube 14 is a conductive material, but compared to other types of conductive materials, the amount required to develop a certain level of sacrificial corrosion resistance is small, so the degree of reduction in adhesive strength is small. It is speculated that

The carbon nanotube 14 is a tubular material made of carbon. The carbon nanotubes 14 have excellent electrical properties, and can form a highly conductive sheet or the like when compounded with a resin or the like. A carbon nanotube is a substance that has a structure in which a graphite sheet with a hexagonal mesh-like carbon atom arrangement is rolled into a cylinder. .
In the anti-corrosion pressure-sensitive adhesive tape 10B of one embodiment of the present invention, the type of carbon nanotubes 14 is not particularly limited, and may be single-wall carbon nanotubes, multi-wall carbon nanotubes, or a mixture containing these in any proportion. Also, carbon nanotubes manufactured by various methods such as an arc discharge method, a laser evaporation method, a chemical vapor deposition method (CVD method), and the like can be used.

The average diameter of the carbon nanotubes 14 is preferably 1-100 nm, more preferably 2-15 nm. The average length of the carbon nanotubes 14 is preferably 0.1-1000 μm, more preferably 10-500 μm. The aspect ratio (average length/average diameter) of the carbon nanotubes 14 is preferably 10-100,000, more preferably 500-30,000.
The diameter of the carbon nanotube 14 indicates the outer diameter in the case of a single-wall carbon nanotube, and means the outer diameter of the outermost tube in the case of a multi-wall carbon nanotube. The diameter and length of the carbon nanotube 14 may be measured, for example, in an image obtained by observation with a TEM (transmission electron microscope), and the average diameter and average length are determined by the arithmetic average of 50 arbitrary numbers. Good.

From the viewpoint of sacrificial corrosion resistance 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% by mass, more preferably 0%, based on the total amount of the adhesive layer. 0.005 to 5 mass %, more preferably 0.006 to 3 mass %.

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% by mass, more preferably 0.0005 to 0.7% by mass, based on the total amount of the adhesive layer. 005 to 0.05% by mass, more preferably 0.006 to 0.045% by mass.
When the content of the carbon nanotubes 14 is at least these lower limits, the sacrificial corrosion resistance tends to be enhanced, and when the content of the carbon nanotubes is at most these upper limits, the adhesive strength tends to be improved.

(adhesive)
The adhesive layer 12 is preferably made of an adhesive. Although the type of adhesive is not particularly limited, acrylic adhesives, rubber-based adhesives, urethane-based adhesives, silicone-based adhesives, and the like can be used. These may be used alone or in combination.
Among these, the adhesive layer 12 is preferably formed of an acrylic adhesive.

(Acrylic adhesive)
The acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing an acrylic polymer obtained by polymerizing a polymerizable monomer containing a (meth)acrylic acid alkyl ester-based 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. . In addition, the term "polymerizable monomer" includes not only compounds having no repeating unit, but also compounds that copolymerize with the (meth)acrylic acid alkyl ester monomer (A), such as the olefin polymer (C) described later. refers to the concept that the monomer itself may include those having repeating units.

((Meth)acrylic acid alkyl ester-based monomer (A))
(Meth)acrylic acid alkyl ester-based monomer (A) is an ester of (meth)acrylic acid and an aliphatic alcohol, and the number of carbon atoms in the alkyl group of the aliphatic alcohol is preferably 2 to 14, more preferably Alkyl esters derived from fatty alcohols that are 4-10 are preferred. When the number of carbon atoms in the alkyl group is within this range, the adhesive strength is easily increased, and the storage elastic modulus at 23° C. of the adhesive described below is easily adjusted within a predetermined range.

Specific (meth)acrylic acid alkyl ester-based monomers (A) include, for example, 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 Acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate and the like.
Among these, n-butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and n-octyl (meth)acrylate are preferred, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate or combinations thereof are more preferred.
The (meth)acrylic acid alkyl ester-based monomers may be used alone, or two or more of them may be used in combination.

The structural unit derived from the (meth)acrylic acid alkyl ester-based monomer (A) constitutes the main component in the adhesive layer 12, and its content is generally 30% by mass based on the total amount of the adhesive layer. Above, preferably 50% by mass or more, more preferably 70% by mass or more. Thus, when the content of the (meth)acrylic acid alkyl ester-based monomer (A) is increased, it becomes possible to impart desired adhesive strength to the adhesive layer 12 . In addition, the content of the structural unit derived from the (meth)acrylic acid alkyl ester-based monomer (A) is, for example, 97% by mass or less, preferably 95% by mass or less, or more, in order to contain a certain amount or more of other components. Preferably, it is 90% by mass or less.
The content of the structural unit derived from the (meth)acrylic acid alkyl ester-based monomer (A) in the adhesive layer 12 is the content of the (meth)acrylic acid alkyl ester-based monomer (A) in the adhesive composition described later. Since it is substantially the same as , it can be expressed by replacing The same applies to components other than the (A) component, such as the (B) and (C) components described below.

(Polar group-containing vinyl monomer (B))
The polymerizable monomer preferably contains a polar group-containing vinyl monomer (B) in addition to the (meth)acrylic acid alkyl ester monomer (A). The polar group-containing vinyl monomer (B) has a polar group and a vinyl group. By using the polar group-containing monomer (B), it becomes easier to improve the adhesive strength to the adherend.
Examples of the polar group-containing vinyl monomer (B) include carboxylic acid vinyl esters such as vinyl acetate, (meth)acrylic acid, carboxylic acids containing a vinyl group such as itaconic acid, and their anhydrides, 2-hydroxyethyl (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, caprolactone-modified (meth) acrylate, polyoxyethylene (meth) acrylate, and polyoxypropylene (meth) acrylate hydroxyl groups such as vinyl monomers having, (meth)acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllauryllactam, (meth)acryloylmorpholine, (meth)acrylamide, dimethyl (meth)acrylamide, N-methylol (meth)acrylamide , N-butoxymethyl (meth)acrylamide, and dimethylaminomethyl (meth)acrylate.
Among these, (meth)acrylic acid, carboxylic acids containing a vinyl group such as itaconic acid, and their anhydrides are preferred, (meth)acrylic acid is more preferred, and acrylic acid is even more preferred. These polar group-containing vinyl monomers (B) may be used alone or in combination of two or more.

When the polar group-containing vinyl monomer (B) is used, the content of the structural unit derived from the polar group-containing vinyl monomer (B) in the adhesive layer is equal to the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A). It is preferably 1 to 15 parts by mass, more preferably 2 to 12 parts by mass, and still more preferably 3 to 10 parts by mass with respect to 100 parts by mass. By setting the content of the polar group-containing vinyl monomer (B) within such a range, it becomes easier to improve the adhesive strength of the anticorrosion pressure-sensitive adhesive tape.

(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), it becomes easy to improve the adhesive strength of the anti-corrosion pressure-sensitive adhesive tape.
The polymerizable bond means an unsaturated carbon-carbon bond capable of polymerizing with a polymerizable monomer, and includes, for example, an unsaturated double bond, preferably a (meth)acryloyl group.
Examples of the olefin polymer (C) include polyolefins having a (meth)acryloyl group at one end. Polyolefins are polymers of aliphatic hydrocarbon compounds having double bonds such as ethylene, propylene, butane, butadiene and isoprene, or hydrogenated products thereof.

As the polyolefin having a (meth)acryloyl group at one end, for example, a polyolefin having a (meth)acryloyl group at one end prepared by reacting polyethylene having an epoxy group at one end with (meth)acrylic acid Polyethylene etc. are mentioned. In addition, polybutadiene having a (meth)acryloyl group at one end or a hydrogenated product thereof may be mentioned, and commercially available products thereof include "L-1253" manufactured by Kuraray Co., Ltd. and the like.

The olefin polymer (C) preferably has a number average molecular weight of 500 to 20,000, more preferably 1,000 to 10,000. The number average molecular weight may be measured by gel permeation chromatography (GPC) and calculated using a standard polystyrene calibration curve.
In addition, the content of the structural unit derived from the olefin polymer (C) in the adhesive layer 12 is 1 to 20 parts by mass with respect to 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A). is preferred, 2 to 15 parts by weight is more preferred, and 4 to 12 parts by weight is even more preferred.

(Crosslinking agent (D))
Preferably, the polymerizable monomer further contains a cross-linking agent. Examples of the cross-linking agent include polyfunctional monomers having two or more vinyl groups, preferably polyfunctional (meth)acrylates having two or more (meth)acryloyl groups. Using a polyfunctional monomer makes it easier to adjust the adhesive strength of the adhesive layer to an appropriate range.
Polyfunctional (meth)acrylates are not particularly limited, and hexanediol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, Polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, liquid hydrogenated 1,2- Examples include polymers such as polybutadiene di(meth)acrylate. Among these polyfunctional (meth)acrylates, polymers are preferred, and liquid hydrogenated 1,2-polybutadiene diacrylate is more preferred. Commercial products of liquid hydrogenated 1,2-polybutadiene diacrylate include “TEAI-1000” manufactured by Nippon Soda Co., Ltd., and the like.
In addition, the content of the structural unit derived from the crosslinking agent in the adhesive layer is preferably 0.1 to 4 parts by mass with respect to 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A), 0.3 to 3 parts by mass is more preferable, and 0.5 to 2 parts by mass is even more preferable.

(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 such as hydrogenated terpene resin, hydrogenated rosin, disproportionated rosin resin, petroleum resin, etc. is preferable. Among these, hydrogenated resins are preferred, and among them, hydrogenated petroleum resins are preferred because polymerization reaction is inhibited when the tackifier resin has a large number of double bonds.
The softening point of the tackifier resin may be about 95°C or higher from the viewpoint of improving the cohesive strength and adhesive strength of the adhesive, but preferably includes 120°C or higher, such as 95°C or higher and 120°C. A temperature of less than 120° C. or more and a temperature of 120° C. or more and 150° C. or less may be used together. The softening point may be measured by the ring and ball method defined in JIS K2207.
The content of the tackifying resin in the acrylic pressure-sensitive adhesive is preferably 5 to 40 parts by mass, more preferably 7 to 35 parts by mass, with respect to 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A). parts by mass, more preferably 10 to 25 parts by mass.

(fine particles)
The acrylic pressure-sensitive adhesive may contain fine particles. Adhesion can be improved by containing fine particles.
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, phenolic resin, etc., glass beads, and silica beads. , inorganic fine particles such as synthetic mica, and organic fine particles such as polyethyl acrylate, 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 parts by mass, with respect to 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A). to 10 parts by mass, more preferably 0.7 to 5 parts by mass.

(other ingredients)
The acrylic pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 12 includes, in addition to the components described above, various additives conventionally used in pressure-sensitive adhesives such as plasticizers, softeners, pigments, dyes, photopolymerization initiators, and flame retardants. may contain.

(Method for producing acrylic pressure-sensitive adhesive and pressure-sensitive adhesive layer)
The acrylic pressure-sensitive adhesive is obtained by irradiating a pressure-sensitive adhesive composition containing the polymerizable monomers described above, a sacrificial anti-corrosion metal used as necessary, and a conductive material to polymerize the polymerizable monomers. is possible. In addition, the pressure-sensitive adhesive composition may contain at least one of the above-described tackifying resin, fine particles, and other components, if necessary.
More specifically, first, a polymerizable monomer, a sacrificial anti-corrosion metal and a conductive material that are blended as necessary, a tackifier resin that is blended as necessary, fine particles, and other components are placed in a glass container. It is put into a reaction vessel such as the above and mixed to obtain an adhesive composition.
Then, in order to remove oxygen dissolved in the adhesive composition, an inert gas such as nitrogen gas is generally supplied to purge oxygen. Then, after the adhesive composition is applied onto a release sheet or a support such as a resin film, woven fabric, or non-woven fabric, the adhesive layer is formed by irradiating with light to polymerize the polymerizable monomer. Obtainable.
It is preferable that the process from the application or impregnation of the pressure-sensitive adhesive composition to the process of irradiating with light is carried out in an inert gas atmosphere or in a state in which oxygen is blocked by a film or the like.
In this production method, the pressure-sensitive adhesive composition obtained by mixing each component may be prepolymerized before being applied to a release sheet or a support in order to increase the viscosity.

(rubber adhesive)
Next, the rubber adhesive used for 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 preferably has a diblock ratio of 25 to 70% by weight, more preferably 30 to 65% by weight, and still more preferably 45 to 60% by weight. Here, diblock means a diblock composed of styrene and isoprene. By setting the diblock ratio within the above range, it becomes easier to increase the adhesive strength. The styrene-isoprene block copolymer includes not only diblocks but also those having three or more blocks such as triblocks composed of styrene, isoprene and styrene blocks.

Although the amount of styrene in the styrene-isoprene block copolymer is not particularly limited, it is preferably 14 to 24% by mass, more preferably 15 to 18% by mass. When the styrene content is 14% by mass or more, the adhesive tends to be highly cohesive. Moreover, when it is 24% by mass or less, the cohesive force becomes an appropriate level, and the adhesive force is easily expressed.
The molecular weight of the styrene-isoprene block copolymer is not particularly limited, but the weight average molecular weight is preferably 100,000 to 400,000, more preferably 150,000 to 250,000. The term "mass average molecular weight" as used herein refers to a molecular weight measured in terms of polystyrene by GPC (gel permeation chromatography).

Various tackifying resins can be used as the tackifying resin used in the rubber-based adhesive, but petroleum-based resins, terpene resins, and coumarone resins are preferably used. The tackifying resin may be used alone or in combination of two or more. However, at least one selected from petroleum-based resins and terpene resins and coumarone resins may be used in combination. preferable. Such a combination of tackifying resins makes it easier to improve the adhesive strength.
Examples of petroleum resins include aliphatic petroleum resins (C5 petroleum resins), alicyclic petroleum resins, and aromatic petroleum resins. family-based petroleum resins are preferred. Further, it is preferable to use a petroleum-based resin having a softening point of about 90 to 120°C.
As the terpene resin, those having a softening point of about 80 to 120° C. can be used, but those having a softening point of less than 100° C. are preferable from the viewpoint of ensuring adhesive strength. As the coumarone resin, one having a softening point of preferably 110 to 130° C., more preferably 115 to 125° C. is used in order to ensure cohesion.

The tackifying resin is preferably 60 to 250 parts by mass, more preferably 100 to 200 parts by mass, even more preferably 110 to 180 parts by mass, based on 100 parts by mass of the rubber component. By setting the blending amount of the tackifying resin within the above range, it becomes possible to improve the cohesive force and impart an appropriate adhesive force.
When a petroleum-based resin and at least one selected from a terpene resin and a cumarone resin are used in combination, the petroleum-based resin is preferably 50 to 200 parts by mass, preferably 60 to 150 parts by mass, with respect to 100 parts by mass of the rubber component. Parts by mass are preferable, and 60 to 110 parts by mass are more preferable. On the other hand, 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 with respect to 100 parts by mass of the rubber component. Furthermore, 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 with respect to 100 parts by mass of the rubber component.
The rubber-based pressure-sensitive adhesive may contain the fine particles described above in the same manner as the acrylic pressure-sensitive adhesive. It may contain agents, fillers, and the like.

(urethane adhesive)
The urethane-based pressure-sensitive adhesive described above is not particularly limited, and examples thereof include urethane resins obtained by reacting at least a polyol with a polyisocyanate compound. Examples of the polyols include polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, and the like. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and the like. These urethane adhesives may be used alone or in combination of two or more.
Moreover, as the urethane-based adhesive, a urethane resin obtained by reacting a polyurethane polyol and a polyfunctional isocyanate-based curing agent may be used. Examples of the polyurethane polyol include those obtained by reacting the above-described polyol with a polyisocyanate compound, and those obtained by reacting a polyol, a polyisocyanate compound, and a chain extender such as a diamine. As the polyfunctional isocyanate-based curing agent, any compound having two or more isocyanate groups may be used, and the isocyanate compounds described above can be used.
In addition to the urethane resin, the urethane-based pressure-sensitive adhesive may contain the above-described fine particles. , antioxidants, fillers, and the like.

(Silicone adhesive)
Examples of the silicone-based pressure-sensitive adhesive include addition-reactive, peroxide-curable, and condensation-reactive silicone-based pressure-sensitive adhesives. Among them, addition reaction-type silicone pressure-sensitive adhesives are preferably used from the viewpoint that they can be cured at a low temperature in a short period of time. The addition reaction type silicone pressure-sensitive adhesive cures when the pressure-sensitive adhesive layer is formed. When an addition-reactive silicone pressure-sensitive adhesive is used as the silicone pressure-sensitive adhesive, the silicone pressure-sensitive adhesive may contain a catalyst such as a platinum catalyst.
In addition, the silicone pressure-sensitive adhesive may contain fine particles, and may contain a cross-linking agent and various additives for controlling adhesive strength.

(Storage modulus G')
The adhesive layer preferably has a storage modulus G' of 50,000 to 1,000,000 Pa at 23°C. When the storage elastic modulus G' at 23°C is within the above range, when the pressure-sensitive adhesive layer is damaged by an external impact or the like, the ability to restore the damaged site to its original state (hereinafter also referred to as self-healing ability) is increased. As a result, the generation of rust is suppressed and the anticorrosion performance is improved. The storage elastic modulus G' can be adjusted by appropriately changing the material constituting the pressure-sensitive adhesive layer, the curing conditions of the pressure-sensitive adhesive layer, and the like.
The storage elastic modulus G′ of the pressure-sensitive adhesive layer at 23° C. is more preferably 200,000 to 800,000 Pa, more preferably 300,000 to 600,000 Pa, from the viewpoint of enhancing self-healing power and improving anticorrosion performance. is.
The storage elastic modulus G 'is, for example, using DVA-200 (manufactured by IT Keisoku Co., Ltd.), shear mode: 10 Hz, strain amount: 0.1%, temperature range: -100 ° C. to 100 ° C., heating rate : It can be calculated by measuring the dynamic viscoelasticity spectrum under the condition of 10°C/min.

(thickness)
The thickness of the adhesive layer 12 is preferably 100 μm or more. By setting the thickness to 100 μm or more, the self-repairing power and the like can be enhanced, and the anticorrosion property of the anticorrosive pressure-sensitive adhesive tape can be improved. From such a viewpoint, the thickness of the pressure-sensitive adhesive layer is more preferably 200 µm or more, still more preferably 300 µm or more, and still more preferably 500 µm or more. Although the upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, it is, for example, 3000 μm from the viewpoint of obtaining the effect of improving the anticorrosion performance according to the thickness.

[Applications of anticorrosion adhesive tape]
The anti-corrosion pressure-sensitive adhesive tape of one embodiment of the present invention is applied to various adherends and used for anti-corrosion of the adherends. Since the anti-corrosion pressure-sensitive adhesive tape of one embodiment of the present invention is excellent in adhesive strength and anti-corrosion properties, it is preferably used by attaching it 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 alloys containing iron. Specific examples of alloys containing iron include nickel-chromium steel, nickel-chromium-molybdenum steel, chromium steel, chromium-molybdenum steel, manganese steel, and other alloy steels, and various steel materials, such as carbon steel.

The anticorrosion pressure-sensitive adhesive tape according to one embodiment of the present invention is preferably used for an adherend having an uneven surface. The anti-corrosion pressure-sensitive adhesive tape of the present invention can be adhered so as to conform to the unevenness of the adherend even if the adherend has unevenness, and is also excellent in anti-corrosion properties for adherends having unevenness on the surface.
Further, the anti-corrosion pressure-sensitive adhesive tape according to one embodiment of the present invention is applied to an adherend, and then heated to, for example, 90 to 150° C., preferably 90 to 130° C., and pressed against various adherends for use. preferably. By applying pressure to the adherend while heating, it is possible to adhere to the adherend having unevenness with high adhesion and ensure high anti-corrosion properties. The adhesive tape may be heated by a known heating device such as an industrial dryer.

The anticorrosive pressure-sensitive adhesive tape according to one embodiment of the present invention is preferably used for repair. The term "for repair" means performing anticorrosion treatment on metal materials such as steel materials that constitute existing structures such as bridges, steel towers, viaducts, tanks, plants, and bridge piers.
Specifically, the existing structure may have a portion where the antirust paint is peeled off, or the cut surface may be exposed by cutting the steel material or the like in the repair work of the structure. The anticorrosive pressure-sensitive adhesive tape of the present invention is preferably used by being attached to a portion where the anticorrosive paint has been peeled off, a cut surface to which the anticorrosive paint is not applied, or the like.
The anti-corrosion pressure-sensitive adhesive tape can prevent corrosion of the adherend by attaching it to the adherend and, if necessary, heating and crimping it. Available.
In addition, the adherend to be repaired often has unevenness, for example, fine unevenness (for example, residual reinforcing bars) is generated on the cut surface after cutting. Even if the body has unevenness, it can maintain high anti-corrosion properties, so it is also suitable for repair.

[Modified example of anticorrosive adhesive tape]
The anticorrosive pressure-sensitive adhesive tape 10 of the present invention can be modified as follows.
(Modification 1)
As shown in FIG. 4, the anticorrosive adhesive tape 10C includes a film 11 having an elongation at break of 150% or more at 100° C. and adhesive layers 12 provided on both surfaces 11a and 11b of the film 11. You may prepare. Thereby, it can be set as a double-sided adhesive tape. At least one of the pressure-sensitive adhesive layers 12, 12 may have the structure described above. Moreover, the pressure-sensitive adhesive layers 12, 12 may all have the same configuration, but they do not have to have the same configuration. For example, one pressure-sensitive adhesive layer may contain a metal having a potential lower than that of iron and a conductive material, and the other pressure-sensitive adhesive layer may not contain these.

(Modification 2)
At least one surface 11b of the film 11 may be further provided with a substrate 15 other than the film 11, as in an anticorrosive pressure-sensitive adhesive tape 10D shown in FIG. Thereby, the film 11 can be protected by the substrate 12 . In addition, it is preferable that the substrate 15 does not impede the elongation of the film 11 as much as possible when the film 11 is heated and stretched.
Furthermore, although not shown, the anti-corrosion pressure-sensitive adhesive tape 10D may be a double-sided pressure-sensitive adhesive tape by further providing a pressure-sensitive adhesive layer on the surface of the substrate 15 opposite to the film side.
The substrate 15 may be directly bonded to the film 11, or may be bonded to the film 11 via an adhesive layer or adhesive layer (not shown).

As the base material 15, nonwoven fabric, paper such as Japanese paper, woven fabric made of natural fiber, synthetic fiber, etc., resin film such as acrylic resin film, fluorine resin film, propylene resin film, polyethylene resin film, flat yarn. cross, etc. Propylene-based resin films include, for example, unstretched polypropylene (CPP) films, oriented polypropylene (OPP) films, and the like. Examples of polyethylene-based films include high-density polyethylene films and low-density polyethylene films. A 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 intersection points.
Although the thickness of the base material 15 is not particularly limited, it is, for example, 10 to 200 μm, preferably 20 to 100 μm.

(Modification 3)
As described above, the pressure-sensitive adhesive layer 12 of the anti-corrosion pressure-sensitive adhesive tape 10 in one embodiment of the present invention does not need to contain a metal having a potential less base than that of iron. In this case, 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 in order to enhance the anticorrosion properties of the anticorrosion adhesive tape 10. It is preferable that 16 is a layer of a metal whose potential is less noble than that of iron. As the metal whose potential is less noble than that of iron, the above-mentioned metals are used without particular limitation, but the metal layer 16 is more preferably a layer of zinc. Specifically, the metal layer 16 may be formed by bonding a metal foil made of a metal having a lower potential than iron to the surface of the pressure-sensitive adhesive layer 12 . Alternatively, the metal layer 16 may be a metal film formed by coating the surface of the pressure-sensitive adhesive layer 11 with a metal by sputtering, vacuum deposition, or the like.

The metal layer 16 is preferably formed directly on the adhesive layer 12 . As a result, the metal having a potential lower than that of iron forming the metal layer 16 comes into contact with the pressure-sensitive adhesive layer 12 . In this way, when a metal having a potential less base than that of iron contacts the adhesive layer 12, the electrons emitted when ionized can easily migrate to the adhesive layer 12, so that the anticorrosive adhesive tape 10E has anticorrosive properties. improves. Moreover, although not shown, in this case also, from the viewpoint of anticorrosion properties of the anticorrosive adhesive tape 10E, the adhesive layer 12 may contain a conductive material 14 other than a metal having a potential less base than that of iron. In this case, the film 11 may be directly bonded to the metal layer 16, or may be bonded to the metal layer 16 via an adhesive layer or adhesive layer (not shown).

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 the ionization of the metal in the metal layer 16, and the anti-corrosion adhesive tape 10E maintains sufficient anti-corrosion properties. can. From the viewpoint of enhancing the anticorrosion property of the anticorrosion pressure-sensitive adhesive tape 10E, the thickness of the metal layer 16 is more preferably 5 μm or more. Moreover, from the viewpoint of minimizing hindrance to the elongation of the film 11 when the film 11 is heated and stretched, the thickness of the metal layer 16 is preferably 200 μm or less, more preferably 100 μm or less.

The anticorrosion pressure-sensitive adhesive tape of one embodiment of the present invention may have a release sheet attached to the surface of the pressure-sensitive adhesive layer. The release sheet may be peeled off from the adhesive layer before using the anticorrosive adhesive tape to expose the adhesive layer, and the exposed adhesive layer may be bonded to the adherend. For example, in a double-sided pressure-sensitive adhesive tape, a release sheet may be attached to both sides of the tape, or a release sheet may be attached to only one side of the tape. In the case of a single-sided pressure-sensitive adhesive tape, it is preferable that a release sheet is attached to one side of the exposed pressure-sensitive adhesive layer.
As the release sheet, a resin film is preferably used, and it is preferable that the surface to be bonded to the pressure-sensitive adhesive layer is a release-treated surface subjected to a release treatment with a silicone release agent or the like.

The anticorrosive adhesive tapes 10, 10A to 10E of one embodiment of the present invention are merely examples of the anticorrosive adhesive tape of the present invention. Therefore, the anticorrosion pressure-sensitive adhesive tape of the present invention is not limited to the anticorrosion pressure-sensitive adhesive tapes 10, 10A to 10E of one embodiment of the present invention.

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

<Evaluation method>
In Examples and Comparative Examples, the anticorrosive pressure-sensitive adhesive tapes were evaluated by the following evaluation methods.
(Elongation at break at 100°C)
Samples were prepared according to JIS K7127 from the films used to prepare the anticorrosive adhesive tapes of each example and comparative example. A tensile test was performed in each of the MD direction and the TD direction, and the elongation at break was calculated from the following formula.
Elongation at break (%) = (L-L ₀ )/L ₀ × 100
where L is the length of the sample at break and _L0 is the length of the sample before tensile testing.
Of the calculated elongations at break in the MD direction and the TD direction, the smaller value was taken as the elongation at break of the film.

(Storage modulus at 23°C)
The storage elastic modulus of the adhesive layer of the anticorrosion adhesive tape at 23 ° C. was measured using a dynamic viscoelasticity measuring device (manufactured by IT Instrumentation & Control Co., Ltd., trade name "DVA-200"), shear mode: 10 Hz, The dynamic viscoelasticity spectrum was measured and calculated under the conditions of strain amount: 0.1%, temperature range: -100°C to 100°C, and heating rate: 10°C/min.

(Presence or absence of rust in cyclic corrosion test)
As described in the specification, JIS K5600-7-9 (Paint General Test Method-Part 7: Long-Term Durability of Coating Film-Section 9: Cyclic Corrosion Test Method-Salt Spray/Dry/Wet, Cycle D) , the presence or absence of rust on the portion of the notch was visually confirmed.

(Adhesive force)
1. Preparation of sample The anticorrosion adhesive tape (width 25 mm, length 100 mm) of each example and comparative example was attached to a SUS plate (width 50 mm, length 125 mm), and 2 kg of the anticorrosion adhesive tape was applied on the attached anticorrosion adhesive tape. A weighted roller was reciprocated twice at a speed of 10±0.5 mm/s to prepare a sample for adhesion evaluation. Initial adhesive strength (adhesive strength before the test) was measured using this adhesive strength evaluation sample.
In addition, a salt spray test was carried out according to Cycle D in Appendix 1 of JIS K5600-7-9 using a separately prepared adhesive strength evaluation sample. The test was performed for 28 cycles (total 168 hours). Then, the adhesive force was measured for the sample for adhesive force evaluation after the salt spray test.
2. Measurement of Adhesive Strength The adhesive strength was measured as follows.
Each adhesive force evaluation sample was fixed to a chuck of a tensile tester ("Tensilon Universal Material Testing Machine" manufactured by A&D Co., Ltd.). After that, the anticorrosion pressure-sensitive adhesive tape was pulled at a peeling angle of 180° and a speed of 300 mm/min for 60 mm or more.

(Convex followability)
A method for testing conformability to convex portions will be described with reference to FIG.
A tester 20 was prepared in which a prism 21 having a size of 10 mm×10 mm×10 mm was attached to the center of a SUS plate. As shown in FIG. 7( a ), the prism 21 of the tester 20 was covered with the anticorrosive adhesive tape 10 of each example and comparative example. In addition, the surface of the adhesive layer side of the anticorrosion adhesive tape 10 was the surface in contact with the tester 20 . Then, after heating the anticorrosive adhesive tape 10 to 100° C., the heated anticorrosive adhesive tape 10 was adhered to the upper surface of the prism 21 as shown in FIG. 7(b). After that, the anticorrosion adhesive tape 10 was pressed (see the arrow of reference numeral 30) to gradually adhere the anticorrosion adhesive tape 10 to the side surface of the prism 21 from top to bottom. Then, the height (h) (see FIG. 7(c)) of the portion (floating portion) on the side surface of the prism 21 where the anticorrosive adhesive tape 10 could not be adhered was measured and evaluated according to the following criteria. In addition, as the height (h) of the floating portion is smaller, the followability of the convex portion of the anticorrosion pressure-sensitive adhesive tape is superior.
○: Height of floating portion is less than 0.5 mm ×: Height of floating portion is 0.5 mm or more

(Practical evaluation of peeling)
The anticorrosion adhesive tape (width 25 mm, length 125 mm) of each example and comparative example was attached to a SUS plate (width 50 mm, length 125 mm), and cured at 23 ° C. for 3 days to prepare a peel evaluation sample. made. Water was sprayed for 5 minutes at a water pressure of 8 MPa from the injection position obliquely above the anticorrosive adhesive tape in the sample for peeling evaluation toward the end side surfaces in the longitudinal direction of the anticorrosive adhesive tape. The position where water is injected (injection position) is a position where the angle between the line connecting the injection position and the center part of the end of the anticorrosion adhesive tape and the SUS plate is 30 °, and the end of the anticorrosion adhesive tape The position was directly above a point 5 cm away from the central part of the part in the horizontal direction.
The peeled distance of the anticorrosive pressure-sensitive adhesive tape after spraying water was measured and evaluated according to the following criteria.
◎ Peeled distance is 0 mm or more and less than 15 mm ○ Peeled distance is 15 mm or more and less than 25 mm × Peeled distance is 25 mm or more

[Example 1]
A pressure-sensitive adhesive composition was prepared according to the formulation shown in Table 1. The adhesive composition was purged with nitrogen to remove dissolved oxygen. Then, a spacer having a thickness of 600 μm was placed on the film 1, and the pressure-sensitive adhesive composition was applied onto the release-treated surface of the release sheet. Next, a release sheet was coated on the applied pressure-sensitive adhesive composition so that the release-treated surface was in contact with the pressure-sensitive adhesive composition. As the release sheet, a PET film (thickness: 50 μm) subjected to silicone release treatment was used.
In this state, the intensity of the chemical lamp was adjusted so that the UV irradiation intensity on the release sheet was 5 mW/cm ² , and the UV light was irradiated from the release sheet side for 15 minutes. An anti-corrosion pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer and a release sheet attached to the pressure-sensitive adhesive layer was thus obtained. The thickness of the adhesive layer was 600 μm. The release sheet of the anticorrosion pressure-sensitive adhesive tape was peeled off, and various evaluations were performed. Table 1 shows the results.

[Examples 2-3, Comparative Examples 1-4]
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 the anticorrosion pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the film shown in Table 1 was used. rice field. Table 1 shows the results.

Each component in Table 1 is 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 “Arcon P140”, manufactured by Arakawa Chemical Industries, Ltd., water Additive petroleum resin, softening point 140°C
Tackifier 2: Product name "Arcon P100", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100 ° C.
Fine particles: trade name “Celstar Z-27”, manufactured by Tokai Kogyo Co., Ltd., glass balloon Zinc particles: manufactured by Sakai Chemical Industry Co., Ltd., trade name “zinc powder #40”, average particle size: 50 μm
Carbon nanotubes (CNT): manufactured by JEIO, trade name “JENOTUBE8A”, average diameter 6 to 9 nm, average length 100 to 200 μm
Carbon-based material: artificial graphite powder, Oriental Sangyo Co., Ltd., trade name "AT-NO.15S", average particle size 13 μm
Cross-linking agent: trade name “TEAI-1000” manufactured by Nippon Soda Co., Ltd. Polymerization initiator: 2,2-dimethoxy-2-phenylacetophenone Film 1: Unstretched polypropylene (CPP) film Film 2: Low density polyethylene (LDPE) film Film 3: Acrylic resin film, manufactured by Mitsubishi Chemical Corporation, trade name "Acryprene MBS121E"
Film 4: Film of ionomer resin in which ethylene-methacrylic acid copolymer molecules are crosslinked with Zn ions, manufactured by Mitsui-Dow Polychemicals Co., Ltd., trade name “Himilan 1855”

The anticorrosion pressure-sensitive adhesive tapes of Examples 1 to 3 are excellent in followability to convex portions and are difficult to peel off. Therefore, it is considered that the anticorrosive pressure-sensitive adhesive tapes of Examples 1 to 3 have excellent anticorrosive properties for adherends having complicated shapes. On the other hand, the anti-corrosion pressure-sensitive adhesive tapes of Comparative Examples 1 and 2 are difficult to peel off, but have poor conformability to convex portions. In addition, the anticorrosive pressure-sensitive adhesive tapes of Comparative Examples 3 and 4 have good conformability to convex portions, but are easily peeled off. For this reason, the anticorrosive pressure-sensitive adhesive tapes of Comparative Examples 1 to 4 cannot sufficiently adhere to adherends having a complicated shape, so the anticorrosion properties to adherends having a complicated shape are lower than those of Examples 1 to 3. It is considered to be inferior to anti-corrosion adhesive tapes.

REFERENCE SIGNS LIST 10 Anticorrosion adhesive tape 11 Film 12 Adhesive layer 13 Metal whose potential is more base than iron 14 Conductive material (carbon nanotube)
15 base material 16 metal layer

Claims (7)

A film having an elongation at break of 150% or more at 100 ° C. and a pressure-sensitive adhesive layer provided on at least one surface of the film, in a cyclic corrosion test in accordance with cycle D in JIS K5600-7-9. An anti-corrosion pressure-sensitive adhesive tape that does not rust and has an adhesive strength of 20 N/25 mm or more after a cyclic corrosion test. The anticorrosion pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 100 µm or more. The anticorrosive pressure-sensitive adhesive tape according to claim 1 or 2, wherein the pressure-sensitive adhesive layer contains a metal having a baser potential than iron. 4. The anticorrosion pressure-sensitive adhesive tape according to claim 3, wherein the metal having a potential lower than that of iron is zinc. The anticorrosion pressure-sensitive adhesive tape according to claim 3 or 4, wherein the pressure-sensitive adhesive layer contains a conductive material other than a metal having a potential lower than that of iron. 6. The anti-corrosion pressure-sensitive adhesive tape according to claim 5, wherein said conductive material is carbon nanotubes. The anticorrosion pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive layer is formed of an acrylic pressure-sensitive adhesive.

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