Adhesive tape and laminate

Abstract

An adhesive tape (10) according to the present disclosure comprises a base material (11) and an adhesive layer (12) that is provided on one surface of the base material (11). The adhesive layer (12) is formed from an acrylic adhesive, and the acrylic adhesive is an adhesive that contains an acrylic polymer obtained by polymerizing a polymerizable monomer including a (meth)acrylic acid alkyl ester monomer (A). The thickness of the adhesive layer (12) is at least 100 μm, and the contact angle with water of the adhesive layer (12) is at least 90 degrees. A laminate according to the present disclosure includes the adhesive tape of the present disclosure and a low-polarity adherend. With the present disclosure, it is possible to provide an adhesive tape capable of exhibiting sufficient adhesive force in a short time after being adhered even in a low-temperature environment, and a laminate that includes the adhesive tape.

Description

Adhesive tape and laminate

[0001] The present disclosure relates to an adhesive tape and a laminate including the adhesive tape.

[0002] Large structures such as viaducts, tunnels, bridges, steel towers, and tanks are often constructed by combining steel and concrete materials. Steel and concrete materials corrode over time, causing rust, cracks, and other defects. When this corrosion progresses, the corroded areas can be repaired, for example, by applying paint or adhesive to the surface of the structure. However, this repair method requires complex work processes and takes a considerable amount of time before the actual repair work can begin. As a result, there are problems such as the rust progressing further in the corroded areas or pieces of concrete falling off from the corroded areas before the actual repair work can begin.

[0003] As a method for simplifying the repair process of corroded areas, it is known to suppress the progression of corrosion by attaching a sheet to the corroded area. However, because the sheet is often highly rigid, the sheet may not be attached to the corroded area in an appropriate manner. Therefore, as disclosed in Patent Document 1, for example, a laminated sheet with excellent conformability has been proposed as a sheet for use in concrete structures or structures having rusted parts.

[0004] JP 2019-64260 A

[0005] However, the anti-rust adhesive film of Patent Document 1 takes a long time to develop sufficient adhesive strength in low-temperature environments such as winter, and there is a problem that the film is easily peeled off from the adherend immediately after application in low-temperature environments. Therefore, an object of the present disclosure is to provide an adhesive tape that can develop sufficient adhesive strength in a short time after application even in low-temperature environments, and a laminate including the adhesive tape.

[0006] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by reducing the polarity of the adhesive layer in the adhesive tape, and have thus completed the present disclosure. The present disclosure provides the following [1] to

[13] . [1] An adhesive tape comprising: a substrate and an adhesive layer provided on one surface of the substrate, wherein the adhesive layer is formed from an acrylic adhesive, and the acrylic adhesive is an adhesive containing an acrylic polymer obtained by polymerizing a polymerizable monomer including a (meth)acrylic acid alkyl ester monomer (A), the adhesive layer having a thickness of 100 μm or more, and the adhesive layer having a contact angle with water of 90 degrees or more. [2] The adhesive tape according to [1] above, wherein the acrylic adhesive is a photocurable adhesive. [3] The adhesive tape according to [1] or [2] above, wherein the polymerizable monomer includes a nitrogen-containing polymerizable monomer. [4] The adhesive tape according to any one of [1] to [3] above, wherein the polymerizable monomer further includes an olefin polymer. [5] The pressure-sensitive adhesive tape according to any one of the above [1] to [4], wherein the polymerizable monomer does not contain a polar group-containing polymerizable monomer (B), or the polymerizable monomer contains a polar group-containing polymerizable monomer (B)-derived structural unit in a proportion of 15 parts by mass or less per 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A). [6] The SP value of the polar group-containing polymerizable monomer (B) is 14 (cal / cm ３ ) １／２[7] The pressure-sensitive adhesive tape according to any one of [1] to [6] above, wherein the pressure-sensitive adhesive layer has a storage modulus (G') at 0°C of 200,000 Pa or more and 1,100,000 Pa or less. [8] The pressure-sensitive adhesive tape according to any one of [1] to [7] above, wherein the substrate is at least one resin film selected from the group consisting of a fluorine-based resin film, a polyester-based resin film, an acrylic-based resin film, and a silicone-based resin film. [9] The pressure-sensitive adhesive tape according to any one of [1] to [8] above, wherein the substrate is a fluorine-based resin film or an acrylic-based resin film.

[10] The pressure-sensitive adhesive tape according to any one of [1] to [9] above, wherein the thickness of the substrate is 20 μm or more and 300 μm or less.

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

[10] above, which is for use on concrete or a low-polarity adherend.

[12] The pressure-sensitive adhesive tape according to any one of [1] to

[11] above, which is for use in corrosion prevention.

[13] A laminate comprising the pressure-sensitive adhesive tape according to any one of [1] to

[12] above and a low-polarity adherend.

[0007] According to the present disclosure, it is possible to provide an adhesive tape that can exhibit sufficient adhesive strength in a short time after application even in a low-temperature environment, and a laminate that includes the adhesive tape.

[0008] 1A and 1B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 2A and 2B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 3A and 3B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 4A and 4B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 5A and 5B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 6A and 6B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 7A and 7B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 8A and 8B are schematic diagrams illustrating an example of the configuration of a pressure-sensitive adhesive tape according to the present disclosure, 9A and 9B are schematic diagrams illustrating an example of

[0009] [Adhesive Tape] The adhesive tape of the present disclosure comprises a substrate and a pressure-sensitive adhesive layer provided on one surface of the substrate. The pressure-sensitive adhesive layer is formed from an acrylic pressure-sensitive adhesive, and 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). Furthermore, the thickness of the pressure-sensitive adhesive layer is 100 μm or more, and the contact angle of the pressure-sensitive adhesive layer with water is 90 degrees or more. This allows the pressure-sensitive adhesive tape of the present disclosure to develop sufficient adhesive strength in a short time after application, even in a low-temperature environment.

[0010] (Contact angle of pressure-sensitive adhesive layer with water) In the pressure-sensitive adhesive tape of the present disclosure, the contact angle of the pressure-sensitive adhesive layer with water is 90 degrees or more. If the contact angle of the pressure-sensitive adhesive layer with water is less than 90 degrees, the pressure-sensitive adhesive layer will have low wettability, and in a low-temperature environment, it will take a long time for the pressure-sensitive adhesive tape to develop sufficient adhesive strength. In a low-temperature environment, the pressure-sensitive adhesive tape may peel off from an adherend immediately after application. One possible reason for this is as follows, but this reason is not limited to the present disclosure. If the contact angle with water is less than 90 degrees, energetically unstable functional groups will be exposed on the surface of the pressure-sensitive adhesive layer. As a result, when the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is brought into contact with an adherend, the intramolecular interactions derived from the functional groups are severed, and the pressure-sensitive adhesive layer will interact with and adhere to the adherend. For this reason, it is presumed that the pressure-sensitive adhesive tape peels off from an adherend immediately after application. From this perspective, the contact angle of the pressure-sensitive adhesive layer with water in the pressure-sensitive adhesive tape of the present disclosure is preferably 100 degrees or more, more preferably 105 degrees or more, and even more preferably 110 degrees or more. The upper limit of the range of the contact angle of the pressure-sensitive adhesive layer with water in the pressure-sensitive adhesive tape of the present disclosure is not particularly limited, but is usually 180 degrees, preferably 150 degrees, more preferably 140 degrees, even more preferably 130 degrees, and even more preferably 120 degrees. The contact angle of the pressure-sensitive adhesive layer with water can be measured by the method described in the Examples below. The contact angle of the pressure-sensitive adhesive layer with water can be increased by decreasing the polarity of the pressure-sensitive adhesive layer. The polarity of the pressure-sensitive adhesive layer can be adjusted by the composition of the acrylic pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer.

[0011] (Adhesive Strength) The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to stainless steel (SUS) at 0°C is preferably 5 N / 15 mm or more. When the adhesive strength of the pressure-sensitive adhesive tape to SUS at 0°C is 5 N / 15 mm or more, peeling of the pressure-sensitive adhesive tape from an adherend immediately after application in a low-temperature environment can be further suppressed. From this perspective, the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to SUS at 0°C is more preferably 7 N / 15 mm or more, and even more preferably 9 N / 15 mm or more. The upper limit of the range of the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to SUS at 0°C is not particularly limited, but the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to SUS at 0°C is typically 100 N / 15 mm or less, for example, 50 N / 15 mm or less, preferably 25 N / 15 mm or less, and more preferably 15 N / 15 mm or less. The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to SUS at 0°C can be measured by the method described in the Examples below. The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to SUS at 0° C. can be adjusted by the composition of the acrylic pressure-sensitive adhesive forming the pressure-sensitive adhesive layer and the thickness of the pressure-sensitive adhesive layer.

[0012] The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to acrylonitrile-butadiene-styrene resin (ABS resin) at 0°C is preferably 5 N / 15 mm or more. When the adhesive strength of the pressure-sensitive adhesive tape to ABS resin at 0°C is 5 N / 15 mm or more, peeling of the pressure-sensitive adhesive tape from an adherend immediately after application in a low-temperature environment can be further suppressed. From this perspective, the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to ABS resin at 0°C is more preferably 8 N / 15 mm or more, even more preferably 9 N / 15 mm or more, and even more preferably 11 N / 15 mm or more. The upper limit of the range of the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to ABS resin at 0°C is not particularly limited, but the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to ABS resin at 0°C is typically 100 N / 15 mm or less, for example, 50 N / 15 mm or less, preferably 25 N / 15 mm or less, and more preferably 15 N / 15 mm or less. The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to ABS resin at 0° C. can be measured by the method described in Examples below. The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to ABS resin at 0° C. can be adjusted by the composition of the acrylic pressure-sensitive adhesive forming the pressure-sensitive adhesive layer and the thickness of the pressure-sensitive adhesive layer.

[0013] The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to mortar at 0°C is preferably 5 N / 15 mm or more. When the adhesive strength of the pressure-sensitive adhesive tape to mortar at 0°C is 5 N / 15 mm or more, peeling of the pressure-sensitive adhesive tape from an adherend immediately after application in a low-temperature environment can be further suppressed. From this perspective, the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to mortar at 0°C is more preferably 8 N / 15 mm or more, even more preferably 9 N / 15 mm or more, and even more preferably 11 N / 15 mm or more. The upper limit of the range of the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to mortar at 0°C is not particularly limited, but the adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to mortar at 0°C is usually 100 N / 15 mm or less, for example, 50 N / 15 mm or less, preferably 25 N / 15 mm or less, and more preferably 15 N / 15 mm or less. The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to mortar at 0°C can be measured by the method described in the Examples below. The adhesive strength of the pressure-sensitive adhesive tape of the present disclosure to mortar at 0° C. can be adjusted by the composition of the acrylic pressure-sensitive adhesive forming the pressure-sensitive adhesive layer and the thickness of the pressure-sensitive adhesive layer.

[0014] (Thickness) The thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape of the present disclosure is 100 μm or more. If the thickness of the pressure-sensitive adhesive layer is less than 100 μm, it may take a long time for the pressure-sensitive adhesive tape to develop sufficient adhesive strength in a low-temperature environment, and the pressure-sensitive adhesive tape may peel off from the adherend immediately after application in a low-temperature environment. From this perspective, the thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape of the present disclosure is preferably 200 μm or more, more preferably 300 μm or more, and even more preferably 400 μm or more. The upper limit of the thickness range of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape of the present disclosure is not particularly limited, but is usually 2500 μm, preferably 2000 μm, more preferably 1500 μm or less, and even more preferably 1200 μm or less. The thickness of the pressure-sensitive adhesive layer may be, for example, 900 μm or less, 750 μm or less, 700 μm or less, or 650 μm or less.

[0015] (Storage Modulus (G')) The storage modulus (G') of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape of the present disclosure at a temperature of 0°C is preferably 200,000 Pa or more and 1,100,000 Pa or less. When the storage modulus (G') of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape at a temperature of 0°C is within the above range, the adhesive strength of the pressure-sensitive adhesive tape is increased, and the protective performance of the pressure-sensitive adhesive tape against an adherend is easily improved. From this perspective, the storage modulus (G') of the pressure-sensitive adhesive layer at a temperature of 0°C is more preferably 250,000 Pa or more and 1,050,000 Pa or less, even more preferably 300,000 Pa or more and 1,000,000 Pa or less, and still more preferably 350,000 Pa or more and 800,000 Pa or less. The storage modulus (G') of the pressure-sensitive adhesive layer at a temperature of 0°C can be measured by the method described in the Examples below. The storage modulus (G') of the pressure-sensitive adhesive layer at a temperature of 0°C can be adjusted by the composition of the acrylic pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer.

[0016] (Adhesive Layer) The adhesive layer in the adhesive tape of the present disclosure is formed from an acrylic adhesive. The acrylic adhesive is an adhesive containing an acrylic polymer obtained by polymerizing a polymerizable monomer including a (meth)acrylic acid alkyl ester monomer (A). <Acrylic Adhesive> As described above, the adhesive layer in the adhesive tape of the present disclosure is formed from an acrylic adhesive. Furthermore, in order to obtain the adhesive layer by irradiating the adhesive composition with light to polymerize the polymerizable monomer, the (meth)acrylic adhesive is preferably a photocurable adhesive. For example, the (meth)acrylic adhesive can be made into a photocurable adhesive by including a photocurable resin in the (meth)acrylic adhesive.

[0017] (Acrylic pressure-sensitive 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 monomer (A). In this specification, the term "(meth)acrylic acid alkyl ester" refers to a concept including both an acrylic acid alkyl ester and a methacrylic acid alkyl ester, and the same applies to other similar terms. In addition, the term "polymerizable monomer" refers to a concept that can include not only compounds that do not have a repeating unit, but also compounds that can copolymerize with a (meth)acrylic acid alkyl ester monomer (A), such as the olefin polymer (C) described below, that have a repeating unit themselves.

[0018] <(Meth)acrylic acid alkyl ester-based monomer (A)> The (meth)acrylic acid alkyl ester-based 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, the adhesive strength is easily increased, and the storage modulus at 23°C of the adhesive, which will be described later, is easily adjusted to a predetermined range.

[0019] Specific examples of the (meth)acrylic acid alkyl ester monomer (A) include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, and tetradecyl (meth)acrylate. Among these, n-butyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and n-octyl(meth)acrylate are preferred, and n-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, or a combination thereof is more preferred. The (meth)acrylic acid alkyl ester monomers may be used alone or in combination of two or more.

[0020] The structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) may be a main component of the pressure-sensitive adhesive layer. Here, "main component of the pressure-sensitive adhesive layer" means that its content is 30% by mass or more, preferably 50% by mass or more, and more preferably 70% by mass or more, based on the total amount of the pressure-sensitive adhesive layer. In this way, increasing the content of the (meth)acrylic acid alkyl ester monomer (A) makes it possible to impart a desired adhesive strength to the pressure-sensitive adhesive layer. Furthermore, the content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) is, for example, 97% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less, in order to contain a certain amount or more of other components.

[0021] From the viewpoint of ensuring adhesive strength, it is more preferable that the (meth)acrylic acid alkyl ester monomer (A) be an alkyl acrylate that constitutes the main component of the adhesive layer, and for example, an alkyl acrylate having about 4 to 8 carbon atoms, such as n-butyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, or n-octyl acrylate, may constitute the main component. Note that the content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) in the adhesive layer is substantially the same as the content of the (meth)acrylic acid alkyl ester monomer (A) in the adhesive composition described below, and therefore can be expressed interchangeably. The same applies to components other than component (A), such as components (B) and (C) described below.

[0022] <Polar Group-Containing Polymerizable Monomer (B)> The polymerizable monomer preferably contains a polar group-containing polymerizable monomer (B) in addition to the (meth)acrylic acid alkyl ester-based monomer (A). The monomer (B) has a polar group and a polymerizable group. The polar group-containing polymerizable monomer (B) preferably has one polymerizable group per molecule. The polar group-containing polymerizable monomer (B) is a monomer copolymerizable with the (meth)acrylic acid alkyl ester-based monomer (A), and the polymerizable group is preferably a polymerizable carbon-carbon double bond formed by a (meth)acryloyl group or a vinyl group, for example. The use of the polar group-containing polymerizable monomer (B) facilitates improving adhesive strength to an adherend. Examples of the polar group-containing polymerizable monomer (B) include a carboxyl group-containing polymerizable monomer, a hydroxyl group-containing polymerizable monomer, and a nitrogen-containing polymerizable monomer.

[0023] The carboxyl group in the carboxyl group-containing polymerizable monomer also includes anhydrides, and specific examples of the carboxyl group-containing polymerizable monomer include polymerizable monomers having a carboxyl group such as (meth)acrylic acid and itaconic acid, and their anhydrides. Examples of the hydroxyl group-containing polymerizable monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone-modified (meth)acrylate, polyoxyethylene (meth)acrylate, and polyoxypropylene (meth)acrylate.

[0024] Examples of the nitrogen-containing polymerizable monomer include those having an amino group or an amide group as a functional group. Specific examples include nitrogen-containing (meth)acrylic monomers such as dimethylaminomethyl (meth)acrylate and dimethylaminomethyl (meth)acrylate, and nitrogen-containing polymerizable monomers other than nitrogen-containing (meth)acrylic monomers such as (meth)acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllaurylolactam, (meth)acryloylmorpholine, (meth)acrylamide, dimethyl(meth)acrylamide, diethyl(meth)acrylamide, and ethylmethyl(meth)acrylamide.

[0025] Among these, nitrogen-containing polymerizable monomers are preferred from the viewpoint of facilitating adjustment of the contact angle of the pressure-sensitive adhesive layer with water. The nitrogen-containing polymerizable monomer is more preferably one having an amide group. Furthermore, the nitrogen-containing polymerizable monomer is more preferably dialkyl(meth)acrylamide, and even more preferably dimethyl(meth)acrylamide.

[0026] The polymerizable monomer may not contain a polar group-containing polymerizable monomer (B). "Not containing a polar group-containing polymerizable monomer (B)" means that a peak derived from the polar group-containing polymerizable monomer (B) is not detected (below the detection limit) in measurements by pyrolysis gas chromatography or infrared spectroscopy. Furthermore, when the polymerizable monomer contains a polar group-containing polymerizable monomer (B), the content of the structural unit derived from the polar group-containing polymerizable monomer (B) in the pressure-sensitive adhesive layer is preferably 15 parts by mass or less, more preferably 14 parts by mass or less, even more preferably 13 parts by mass or less, and preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 0.9 parts by mass or more, per 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A). By setting the content of the polar group-containing polymerizable monomer (B) within this range, the adhesive strength of the pressure-sensitive adhesive tape can be easily improved.

[0027] It is preferable to use a nitrogen-containing polymerizable monomer as the polar group-containing polymerizable monomer (B) as described above. In terms of the contact angle of the pressure-sensitive adhesive layer with water, the content of the constitutional unit derived from the nitrogen-containing polymerizable monomer in the pressure-sensitive adhesive layer is preferably 1 part by mass or more and 15 parts by mass or less, more preferably 2 parts by mass or more and 14 parts by mass or less, and even more preferably 3 parts by mass or more and 13 parts by mass or less, relative to 100 parts by mass of the constitutional unit derived from the (meth)acrylic acid alkyl ester-based monomer (A).

[0028] In a preferred embodiment of the present disclosure, the polymerizable monomer does not contain a carboxyl group-containing polymerizable monomer, or when the polymerizable monomer contains a carboxyl group-containing polymerizable monomer, the polymerizable monomer contains the carboxyl group-containing polymerizable monomer in the following proportions. Note that "the polymerizable monomer does not contain a carboxyl group-containing polymerizable monomer" means that a peak derived from the carboxyl group-containing polymerizable monomer is not detected (below the detection limit) in measurement by pyrolysis gas chromatography or infrared spectroscopy. When the polar group-containing polymerizable monomer (B) contains a carboxyl group-containing polymerizable monomer, the content of the structural unit derived from the carboxyl group-containing polymerizable monomer in the pressure-sensitive adhesive layer is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A). By keeping the content of the structural unit derived from the carboxyl group-containing polymerizable monomer to 15 parts by mass or less, the pressure-sensitive adhesive layer can be prevented from becoming too hard. If the pressure-sensitive adhesive layer becomes too hard, the adhesive strength of the pressure-sensitive adhesive layer will decrease. Furthermore, by setting the content of the structural unit derived from a carboxyl group-containing polymerizable monomer to 15 parts by mass or less, the contact angle of the pressure-sensitive adhesive layer with water can be increased. Since the polymerizable monomer preferably does not contain a carboxyl group-containing polymerizable monomer, the lower limit of the range of the content of the structural unit derived from a carboxylic acid containing a vinyl group in the pressure-sensitive adhesive layer is 0 parts by mass. By setting the content of the carboxyl group-containing polymerizable monomer within this range, the adhesive strength that develops in a short time after application in a low-temperature environment can be further improved.

[0029] The SP value of the polar group-containing polymerizable monomer (B) is preferably 14 (cal / cm ３ ) １／２ The SP value of the polar group-containing polymerizable monomer (B) is 14 (cal / cm ３ ) １／２When the SP value is less than 90°, the polarity of the pressure-sensitive adhesive layer is further reduced, and it becomes easier to make the contact angle of the pressure-sensitive adhesive layer with water 90° or more. The SP value is a value calculated by the Fedors method based on the following formula (1), and its unit is (cal / cm ３ ) １／２ SP value = (ΣΔe ｉ / ΣΔv ｉ ) １／２ (1) In the above formula (1), Δe ｉ is the evaporation energy of atoms and atomic groups (cal / mol), and Δv ｉ is the molar volume (cm ３ / mol). Note that Δe ｉ and Δv ｉ is described in R. F. Fedors, "Polymer Engineering & Science" (Vol. 14, No. 2, 1974, pp. 147-154). The SP value is known to be an index showing the polarity of a monomer, and it is generally known that the larger the SP value of a monomer, the greater the polarity. From the viewpoint of reducing the polarity of the pressure-sensitive adhesive layer, the SP value of the polar group-containing polymerizable monomer (B) is more preferably 13.0 (cal / cm ３ ) １／２ and more preferably 12.5 (cal / cm ３ ) １／２ The lower limit of the range of the SP value of the polar group-containing polymerizable monomer (B) is not particularly limited, but the SP value of the polar group-containing polymerizable monomer (B) is usually 8 (cal / cm ３ ) １／２ and preferably 9 (cal / cm ３ ) １／２ That's all.

[0030] <Olefin Polymer (C)> The polymerizable monomer preferably contains an olefin polymer (C), and more preferably contains an olefin polymer (C) having a polymerizable bond at one end. Use of such an olefin polymer (C) facilitates improving the adhesive strength of the pressure-sensitive adhesive tape. The polymerizable bond refers to an unsaturated carbon-carbon bond that can be polymerized with the polymerizable monomer, and examples thereof include unsaturated double bonds, preferably (meth)acryloyl groups. Examples of the olefin polymer (C) include polyolefins 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.

[0031] 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 polybutadiene having a (meth)acryloyl group at one end or hydrogenated products thereof, and examples of commercially available products include "L-1253" manufactured by Kuraray Co., Ltd.

[0032] The number average molecular weight of the olefin polymer (C) is preferably 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 calibration curve of standard polystyrene. The content of the structural unit derived from the olefin polymer (C) in the pressure-sensitive adhesive layer is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 4 to 12 parts by mass, per 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A).

[0033] <Tackifier Resin (D)> The acrylic pressure-sensitive adhesive may contain a tackifier resin (D) from the viewpoint of improving adhesive strength. Preferred tackifier resins (D) are those with low polymerization inhibition properties, such as hydrogenated terpene resins, hydrogenated rosins, disproportionated rosin resins, and petroleum resins. Among these, hydrogenated resins are preferred, since tackifier resins with many double bonds inhibit the polymerization reaction, and hydrogenated petroleum resins are particularly preferred. The softening point of the tackifier resin (D) may be about 95°C or higher from the viewpoint of improving the cohesive strength and adhesive strength of the pressure-sensitive adhesive, but preferably includes tackifier resins with a softening point of 120°C or higher. For example, a tackifier resin with a softening point of 95°C or higher but lower than 120°C and a tackifier resin with a softening point of 120°C or higher but lower than 150°C may be used in combination. The softening point may be measured by the ring and ball method specified in JIS K2207. The content of the tackifier resin (D) in the acrylic pressure-sensitive adhesive is preferably 3 parts by mass or more and 40 parts by mass or less, more preferably 4 parts by mass or more and 35 parts by mass or less, and even more preferably 5 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester-based monomer (A).

[0034] <Crosslinking Agent (E)> The polymerizable monomer preferably further contains a crosslinking agent (E). Examples of the crosslinking agent (E) include polyfunctional monomers having two or more vinyl groups, and preferably polyfunctional (meth)acrylates 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 bifunctional alkyl (meth)acrylates such as hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, proxied trimethylolpropane triacrylate, proxied 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. Bifunctional alkyl (meth)acrylates are also preferred, and commercially available products include A-HD-N from the NK Ester series manufactured by Shin-Nakamura Chemical Co., Ltd. The content of the structural units derived from the crosslinking agent (E) in the pressure-sensitive adhesive layer is preferably 0.005 parts by mass or more and 3 parts by mass or less, more preferably 0.01 parts by mass or more and 2.0 parts by mass or less, and even more preferably 0.02 parts by mass or more and 1.5 parts by mass or less, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[0035] <Photopolymerization initiator (F)> From the viewpoint of converting the (meth)acrylic pressure-sensitive adhesive into a photocurable pressure-sensitive adhesive, it is preferable that the polymerizable monomer further contains a photopolymerization initiator (F). The photopolymerization initiator (F) is, for example, a compound that generates radicals upon irradiation with light and initiates a radical polymerization reaction. Examples of the photopolymerization initiator (F) include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; alkylphenone compounds such as 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methylpropiophenone; acetophenone compounds such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino ... aminoacetophenone compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, etc.; thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, etc.; ketal compounds such as acetophenone dimethyl ketal, benzyl dimethyl ketal, etc.; acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, etc.;Examples of the photopolymerization initiator (F) include oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-2-(o-benzoyloxime)], ethanone, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyloxime); and titanocene compounds such as bis(cyclopentadienyl)-di-phenyl-titanium, bis(cyclopentadienyl)-di-chloro-titanium, bis(cyclopentadienyl)-bis(2,3,4,5,6-pentafluorophenyl)titanium, and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrol-1-yl)phenyl)titanium. These photopolymerization initiators (F) may be used alone or in combination of two or more. Among these photopolymerization initiators (F), acetophenone compounds are preferred, and 2,2-dimethoxy-2-phenylacetophenone is more preferred.

[0036] A photopolymerization initiation aid may be used together with the photopolymerization initiator. Examples of the photopolymerization initiation aid include N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine. Photopolymerization initiation aids other than these may also be used. The photopolymerization initiation aids may be used alone or in combination of two or more.

[0037] The content of the photopolymerization initiator (F) in the polymerizable monomer is preferably 0.005 parts by mass or more and 3 parts by mass or less, more preferably 0.01 parts by mass or more and 2.0 parts by mass or less, and even more preferably 0.02 parts by mass or more and 1.5 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic acid alkyl ester-based monomer (A).

[0038] The adhesive layer of the adhesive tape of the present disclosure may contain a metal having a lower potential than iron. When the adhesive layer contains a metal having a lower potential than iron, the adhesive tape has sacrificial anticorrosion properties, and when the adherend is a metal material, the corrosion prevention properties of the adhesive tape are further improved. The metal having a lower potential than iron is preferably dispersed in the adhesive constituting the adhesive layer.

[0039] <Metals with a lower potential than iron> Examples of metals with a lower potential than iron (hereinafter also referred to as "sacrificial corrosion protection metals") include cadmium, chromium, zinc, manganese, aluminum, etc., of which zinc and aluminum are preferred, and zinc is particularly preferred. Use of zinc results in excellent sacrificial corrosion protection.

[0040] The content of the sacrificial metal in the pressure-sensitive adhesive layer is preferably 40% by mass or less, based on the total amount of the pressure-sensitive adhesive layer. When the content of the sacrificial metal in the pressure-sensitive adhesive layer is 40% by mass or less, the adhesiveness of the pressure-sensitive adhesive tape becomes even better. From this viewpoint, the content of the sacrificial metal in the pressure-sensitive adhesive layer is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and even more preferably 12% by mass or less. Furthermore, from the viewpoint of the sacrificial corrosion protection of the pressure-sensitive adhesive tape, the content of the sacrificial metal in the pressure-sensitive adhesive layer is, for example, 4.5% by mass or more, preferably 5% by mass or more, more preferably 6% by mass or more, and even more preferably 8% by mass or more.

[0041] <Conductive Material> In addition to the sacrificial metal, the pressure-sensitive adhesive layer preferably further contains a conductive material other than the sacrificial metal. The inclusion of a conductive material facilitates the transfer of electrons released when the sacrificial metal is ionized to the adherend, thereby improving sacrificial protection. Examples of conductive materials include 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, metals with a more noble potential than iron, such as gold, silver, copper, nickel, or alloys containing these. Examples of metal oxide-based 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, and derivatives thereof. Examples of ionic polymers include sodium polyacrylate and potassium polyacrylate. These conductive materials may be used alone or in combination of two or more. Among the above, carbon-based materials are preferred as the conductive material, and carbon nanotubes are more preferred.

[0042] <Carbon nanotubes> The pressure-sensitive adhesive layer preferably contains carbon nanotubes. By containing carbon nanotubes, the sacrificial corrosion protection of the pressure-sensitive adhesive layer is improved and high adhesive strength can be maintained, making it easier to obtain a pressure-sensitive adhesive tape that has good adhesive strength, sacrificial corrosion protection, and sacrificial corrosion protection stability. This is presumably because, although carbon nanotubes are a conductive material, a smaller amount is required to exhibit a certain level of sacrificial corrosion protection compared to other types of conductive materials, and therefore the degree of decrease in adhesive strength is small.

[0043] Carbon nanotubes are tubular materials formed from carbon. Carbon nanotubes have excellent electrical properties, and when combined with resins or the like, they can form highly conductive sheets. Carbon nanotubes are substances with a cylindrical structure in which graphite sheets with a hexagonal mesh-like carbon atom arrangement are wound. Those wound in one layer are called single-wall carbon nanotubes, and those wound in multiple layers are called multi-wall carbon nanotubes. In the pressure-sensitive adhesive tape of one embodiment of the present disclosure, the type of carbon nanotube is not particularly limited, and may be any of single-wall carbon nanotubes, multi-wall carbon nanotubes, or 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.

[0044] From the viewpoint of the sacrificial corrosion protection and adhesive strength of the adhesive layer, the content of the conductive material in the adhesive layer is preferably 0.005 mass% or more and 10 mass% or less, more preferably 0.007 mass% or more and 5 mass% or less, and even more preferably 0.01 mass% or more and 3 mass% or less, based on the total amount of the adhesive layer.

[0045] When the conductive material is carbon nanotubes, the content of the carbon nanotubes in the pressure-sensitive adhesive layer is preferably 0.005% by mass or more and 0.1% by mass or less, more preferably 0.007% by mass or more and 0.05% by mass or less, and even more preferably 0.01% by mass or more and 0.03% by mass or less, based on the total amount of the pressure-sensitive adhesive layer. When the content of carbon nanotubes is equal to or more than these lower limits, sacrificial corrosion protection is likely to be improved, and when the content of carbon nanotubes is equal to or less than these upper limits, adhesive strength is likely to be improved.

[0046] <Fine Particles> The acrylic pressure-sensitive adhesive may contain fine particles. The inclusion of fine particles can further improve adhesive strength. Examples of the 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 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 0.3 to 10 parts by mass, and even more preferably 0.5 to 7 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[0047] <Other Components> In addition to the components described above, the acrylic pressure-sensitive adhesive used in the pressure-sensitive adhesive layer may contain various additives conventionally used in pressure-sensitive adhesives, such as plasticizers, softeners, pigments, dyes, flame retardants, and thickeners.

[0048] <Method for Producing Acrylic Pressure-Sensitive Adhesive and Pressure-Sensitive Adhesive Layer> When the acrylic pressure-sensitive adhesive is photocurable, it can be obtained by irradiating a pressure-sensitive adhesive composition containing the above-described polymerizable monomer and optional additives with light to polymerize the polymerizable monomer. More specifically, the polymerizable monomer, optional additives, and other components are first mixed in a reaction vessel such as a glass vessel to obtain a pressure-sensitive adhesive composition. Next, to remove dissolved oxygen from the pressure-sensitive adhesive composition, an inert gas such as nitrogen gas is generally supplied to purge the oxygen. The pressure-sensitive adhesive composition is then applied to a release sheet or 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 applying or impregnating the pressure-sensitive adhesive composition to irradiating with light are preferably carried out under an inert gas atmosphere or in a state where oxygen is blocked by a film or the like. In this production method, the pressure-sensitive adhesive composition obtained by mixing the components may be pre-polymerized before being applied to a release sheet or support to increase viscosity. In addition, the acrylic pressure-sensitive adhesive can be produced by a method other than photocuring, and may be produced by mixing an acrylic polymer obtained by polymerizing the above-mentioned polymerizable monomer by a method other than photopolymerization with additives and other components that are blended as needed.

[0049] <Substrate> The substrate in the pressure-sensitive adhesive tape of the present disclosure is preferably one with excellent flexibility from the viewpoint of curved surface conformability. Examples of the substrate in the pressure-sensitive adhesive tape of the present disclosure include sheet-like materials such as resin films, woven fabrics, knitted fabrics, nonwoven fabrics, and metal foils. Examples of resin films include polyethylene-based resin films, polypropylene-based resin films, acrylic-based resin films, fluorine-based resin films, polyvinyl chloride-based resin films, polycarbonate-based resin films, AES-based resin films, ASA-based resin films, silicone-based resin films, and styrene-based elastomer films. Examples of woven fabrics include woven fabrics made of natural fibers such as cotton, and synthetic resin fibers such as rayon, acetate, nylon, polyethylene terephthalate (PET), polyethylene, and polypropylene. Examples of knitted fabrics include natural fibers such as cotton, and synthetic resin fibers such as rayon, acetate, nylon, polyethylene terephthalate (PET), polyethylene, and polypropylene. The nonwoven fabric is, for example, a nonwoven fabric made of synthetic resin fibers such as polyamide, polyester, polyacrylic, polyolefin, or polyurethane. Examples of metal foils include metal foils of iron and its alloys, metal foils of metals with a lower potential than iron, such as chromium, zinc, titanium, aluminum, and magnesium, and metal foils of metals with a higher potential than iron, such as gold, silver, copper, tin, nickel, and cobalt. These sheet-like materials can be used alone or in combination of two or more. From the viewpoint of corrosion resistance of the pressure-sensitive adhesive tape, the substrate is preferably a metal foil of a metal with a lower potential than iron, more preferably zinc foil. When the substrate is a metal foil of a metal with a lower potential than iron, it is preferred that the substrate be directly laminated on the pressure-sensitive adhesive layer.From the viewpoint of protecting the pressure-sensitive adhesive layer, the substrate is preferably a resin film, more preferably at least one resin film selected from the group consisting of polyolefin resin films such as polyethylene resin films and polypropylene resin films, acrylic resin films, fluorine-based resin films, polyester resin films, silicone resin films, styrene-based elastomer films, and polyvinyl chloride resin films, and even more preferably at least one resin film selected from the group consisting of fluorine-based resin films, polyester resin films, acrylic resin films, and silicone resin films. Among these, fluorine-based resin films and acrylic resin films are preferred from the viewpoint of weather resistance.

[0050] The thickness of the substrate is preferably 20 μm or more and 300 μm or less, more preferably 30 μm or more and 250 μm or less, and even more preferably 40 μm or more and 200 μm or less. When the substrate has a thickness of 20 μm or more, it can function as a support. Furthermore, when the thickness is 300 μm or less, it is easy to improve adhesion to the adherend.

[0051] (Protective Layer) The pressure-sensitive adhesive tape may be provided with a protective layer on the surface of the pressure-sensitive adhesive layer opposite to the surface on the substrate side. The protective layer is a member that protects the pressure-sensitive adhesive layer from scratches and adhesion of foreign matter. The protective layer is preferably formed from a resin film. The resin used in the resin film for the protective layer is preferably a thermoplastic resin, but may be a resin other than a thermoplastic resin. Specific examples of the resin film for the protective layer are the same as those listed as the resin film used in the substrate. The resin film used in the protective layer and the resin film used in the substrate may be the same or different.

[0052] The resin film forming the protective layer may be a single-layer film consisting of one single layer, or may be a multilayer film consisting of two or more layers. Furthermore, in the resin film constituting the protective layer, the resin contained in the resin film may be used alone, or two or more types may be used in combination. When two or more types of resins are used in combination, a multilayer film may be formed by using different types of resins in each layer. Furthermore, a single-layer film may be formed by mixing two or more types of resins, or one or more layers in a multilayer film may be formed by mixing two or more types of resins. Furthermore, the resin film used in the protective layer may be a stretched resin film or a non-stretched resin film.

[0053] The protective layer may have at least one surface that has been subjected to a release treatment with a release agent such as a silicone-based release agent, a long-chain alkyl-based release agent, or a fluorine-based release agent. When the protective layer is release-treated, it is preferable that the release-treated surface constitutes the surface on the resin layer side. The release treatment of the protective layer makes it easier to releasably release the protective layer from the resin layer. However, the protective layer does not need to be release-treated as long as it can be peeled from the resin layer. The thickness of the protective layer is not particularly limited, but is preferably 20 μm or more and 300 μm or less, more preferably 30 μm or more and 250 μm or less, and even more preferably 40 μm or more and 200 μm or less.

[0054] (Configuration of Adhesive Tape) An example of the configuration of the adhesive tape of the present disclosure is shown in Figures 1 to 3. As shown in Figure 1, the adhesive tape 10 may be a single-sided adhesive tape including a substrate 11 and an adhesive layer 12 provided on one side of the substrate 11. Alternatively, as shown in Figure 2, the adhesive tape 10 may be a double-sided adhesive tape including a substrate 11, an adhesive layer 12 provided on one side of the substrate 11, and an adhesive layer 13 provided on the other side of the substrate 11. Furthermore, as shown in Figure 3, the adhesive tape 10 may be a tape including a substrate 11, an adhesive layer 12 provided on one side of the substrate 11, and a protective layer 14 provided on the side of the adhesive layer 12 opposite to the surface facing the substrate. In this specification, "an adhesive layer provided on one side of the substrate" means that an adhesive layer is provided on at least one side of the substrate.

[0055] (Uses of the Adhesive Tape) The adhesive tape of the present disclosure is used by being attached to various adherends, and the type of adherend is not particularly limited. The adhesive tape of the present disclosure has excellent adhesive strength in low-temperature environments, and is therefore particularly suitable for concrete adherends. The adhesive tape of the present disclosure is used as a protective tape to protect the adherend, and can protect the adherend from corrosion and prevent deterioration and damage. For example, by attaching the adhesive tape of the present disclosure to an aged or damaged concrete structure, it is possible to prevent further deterioration or damage, which could lead to the concrete peeling. In this specification, concrete is considered to include mortar. Furthermore, when the adherend is used in the sea, it can also be suitably used to prevent the attachment of marine organisms. When the adherend is used in the sea, examples of the adherend include resin molded bodies such as floats and concrete.

[0056] The pressure-sensitive adhesive tape of the present disclosure is also suitable for low-polarity adherends, such as steel materials such as SUS (stainless steel), and resin materials such as ABS, polyethylene, and polypropylene, with ABS being particularly suitable. The pressure-sensitive adhesive tape of the present disclosure has excellent adhesive strength to low-polarity adherends in low-temperature environments and can also be suitably used as a protective tape to prevent deterioration of these low-polarity adherends. In this specification, a low-polarity adherend refers to an adherend having a contact angle with water of 60 degrees or more. The contact angle with water of a low-polarity adherend can be measured by the method described in the Examples below.

[0057] The pressure-sensitive adhesive tape of the present disclosure can also be used for corrosion prevention of adherends made of various metal materials, and 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, in addition to SUS, 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. Furthermore, the pressure-sensitive adhesive tape of the present disclosure has excellent adhesive strength in low-temperature environments, and therefore also has excellent corrosion prevention properties in low-temperature environments.

[0058] The adherends to which the pressure-sensitive adhesive tape of the present disclosure is applied are not particularly limited, and examples thereof include buildings, air conditioning equipment, building facilities, buried pipes, sanitary facilities, chemical plants, roads, bridges, and other lifelines, automobiles, railway vehicles, ships, tanks, electrical equipment, electronic devices, resin molded bodies, etc. Furthermore, as the material of the adherend, as described above, metal materials such as steel, concrete, and low-polarity materials are preferred, and more specifically, concrete structures, steel structures, and low-polarity adherends are particularly preferred. Furthermore, the resin molded body is more preferably used for floats that can be used in the sea, and the resin material constituting the resin molded body may be a low-polarity material, etc.

[0059] Another embodiment of the present disclosure also provides a composite comprising the above-mentioned adherend and the above-mentioned pressure-sensitive adhesive tape applied to the adherend. The adherend is not particularly limited, but is preferably a low-polarity adherend. According to the present disclosure, deterioration of a low-polarity adherend can be prevented and the adhesive has excellent adhesive strength in low-temperature environments, so deterioration of the low-polarity adherend can be prevented even in low-temperature environments. Preferred low-polarity adherends include steel (preferably SUS (stainless steel)) and resin materials (preferably ABS, polyethylene, and polypropylene). The adhesive also has excellent adhesive strength in low-temperature environments for adherends such as concrete structures and steel structures. Another embodiment of the present disclosure also provides use of the above-mentioned pressure-sensitive adhesive tape to prevent deterioration of a low-polarity adherend.

[0060] The pressure-sensitive adhesive tape of the present disclosure may be directly attached to an adherend. Alternatively, the pressure-sensitive adhesive tape of the present disclosure may be attached to an adherend via a primer layer. For example, the surface of the adherend may be coated with a primer paint, and the pressure-sensitive adhesive tape of the present disclosure may be attached to the primer layer formed from the primer paint while the primer paint applied to the adherend is still wet.

[0061] The primer coating preferably contains an epoxy resin. The epoxy resin is preferably a resin having at least two epoxy groups per molecule, such as one obtained by reacting a polyhydric alcohol or polyhydric phenol with a halohydrin. Specific examples include bisphenol A epoxy resins, halogenated bisphenol A epoxy resins, novolac epoxy resins, polyglycol epoxy resins, bisphenol F epoxy resins, epoxidized oils, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether. Modified versions of these epoxy resins, such as amine-modified epoxy resins, isocyanate-modified epoxy resins, acrylic-modified epoxy resins, urethane-modified epoxy resins, and polyester-modified epoxy resins, are also included. These epoxy resins may be used alone or in combination of two or more.

[0062] The above primer coating may contain other components, such as other resins, curing agents, pigments, thickeners, rust inhibitors, dispersants, antifoaming agents, leveling agents, anti-settling agents, anti-sagging agents, curing accelerators, anti-algae agents, anti-mold agents, preservatives, ultraviolet absorbers, and light stabilizers, as needed.

[0063] The means for applying the primer coating is not particularly limited, and known coating means such as brush coating, roller coating, trowel coating, spatula coating, flow coater coating, and spray coating (e.g., aerosol spray coating, air spray coating, airless spray coating, etc.) can be used.

[0064] [Laminate] The laminate of the present disclosure includes the pressure-sensitive adhesive tape of the present disclosure and a low-polarity adherend. Note that the pressure-sensitive adhesive tape of the present disclosure and the low-polarity adherend in the laminate of the present disclosure have already been described above in the section "Adhesive Tape," and therefore description of the pressure-sensitive adhesive tape of the present disclosure and the low-polarity adherend in the laminate of the present disclosure will be omitted.

[0065] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to these examples.

[0066] [Evaluation method]

[0067] In the examples and comparative examples, the pressure-sensitive adhesive layer was evaluated by the following evaluation method. (Contact angle with water) The contact angle with water of the pressure-sensitive adhesive layer was measured using a fully automatic contact angle measuring meter (manufactured by Kyowa Interface Science Co., Ltd., product name "DM-701") under the following conditions. The measurement was carried out on a selected smooth surface of the pressure-sensitive adhesive layer within 5 minutes after peeling off the protective film from the pressure-sensitive adhesive tape. Measurement environment: 23±1°C, 50±5% RH Number of repetitions: 10 times Amount of purified water droplet: 3 μl Measurement time: 10 seconds after dropping Screen analysis method: θ / 2 method

[0068] (Storage modulus (G') at 0°C) The storage modulus (G') at 0°C was measured using a polymer dynamic viscoelasticity measuring device "DVA-200" (manufactured by IT Measurement Control Co., Ltd.) under the following conditions: Measurement mode: Shear heating rate: 6°C / min Measurement temperature: -50 to 200°C Set strain: 0.1% Vibration frequency: 10 Hz

[0069] In the examples and comparative examples, the adherends were evaluated by the following evaluation method. (Contact angle with water) The contact angle with water of the adherend was measured using a fully automatic contact angle measuring meter (manufactured by Kyowa Interface Science Co., Ltd., product name "DM-701") under the following conditions: Measurement environment: 23±1°C, 50±5% RH Number of repetitions: 10 times Amount of purified water droplet: 3 μl Measurement time: 10 seconds after dropping Screen analysis method: θ / 2 method

[0070] In the Examples and Comparative Examples, the pressure-sensitive adhesive tapes were evaluated using the following evaluation method. (Adhesive Strength) After cutting the pressure-sensitive adhesive tape to a length of 100 mm x 15 mm, the pressure-sensitive adhesive tape, each of the adherends (SUS plate, ABS plate, and mortar plate), and a 2 kg roller were placed in an environmental test chamber at 0°C and stored for one day. The tape was then bonded to each of the adherends via the adhesive layer to prepare a measurement sample. The 2 kg roller was reciprocated twice at a speed of 10±0.5 mm / s to bond the tape to the adherend. The test sample was fixed to the chuck of a tensile tester ("Tensilon Universal Tester" manufactured by A&D Co., Ltd.). One minute after bonding to the adherend, the measurement sample was pulled at a peel angle of 180° at a speed of 300 mm / min for 60 mm or more at 0°C, and the average value of the load (N) detected by the load cell was recorded and used as the adhesive strength (N / 15 mm). The SUS plates used were made of SUS304 with a BA surface finish, and the mortar plates used were made in accordance with the method specified in JIS R 5201, 11.5.

[0071] (Peel resistance) Based on the above measured adhesive strength, the peel resistance of the pressure-sensitive adhesive tape was evaluated according to the following criteria: A: Adhesive strength was 5 N / 15 mm or more when the adherend was a SUS plate, an ABS plate, or a mortar plate. B: Adhesive strength was less than 5 N / 15 mm when the adherend was at least one of a SUS plate, an ABS plate, and a mortar plate.

[0072] (Weather Resistance) The gloss retention was measured as follows in accordance with JIS K 5600-4-7. A weather resistance test was conducted on the pressure-sensitive adhesive tapes of the Examples and Comparative Examples using cycle A in accordance with JIS K 5600-7-7. The gloss of the surface of the pressure-sensitive adhesive tape after the test was then measured. The gloss retention was calculated using the gloss value of the pressure-sensitive adhesive tape after the test (gloss value after the test) thus obtained and the gloss value of the pressure-sensitive adhesive tape before the test (gloss value before the test) according to the following formula: Gloss retention (%) = 100 × (gloss value after the test) / (gloss value before the test). The gloss value is the gloss value under a geometrical condition of 60°, and is a value measured using a gloss meter (manufactured by Horiba, Ltd., product name: "IG-340"). Based on the gloss retention, the weather resistance of the pressure-sensitive adhesive tape was evaluated according to the following criteria: A: The gloss retention of the pressure-sensitive adhesive tape was 80% or more, and therefore the weather resistance of the pressure-sensitive adhesive tape was good. B: The gloss retention of the adhesive tape was less than 80%, so the weather resistance of the adhesive tape was poor.

[0073] [Examples 1 to 9, Comparative Examples 1 and 2] Pressure-sensitive adhesive compositions were prepared according to the formulations shown in Table 1. Nitrogen was purged into the pressure-sensitive adhesive composition to remove dissolved oxygen. Next, the pressure-sensitive adhesive composition was applied onto a separator (PET film, manufactured by Nakamoto Pax Co., Ltd., product name: "NS-50-MA", thickness 50 μm). Then, the same separator was placed on top of the pressure-sensitive adhesive composition applied onto the separator. In this state, the ultraviolet irradiation intensity was 1 mW / cm 2 The lamp intensity of the chemical lamp was adjusted so that ultraviolet light was irradiated from the protective layer side for 5 minutes, resulting in a pressure-sensitive adhesive layer consisting of a separator, a pressure-sensitive adhesive layer, and a separator. The separator on the irradiated side of the prepared pressure-sensitive adhesive layer was peeled off, and the substrates were bonded together to obtain a pressure-sensitive adhesive tape. The separator was peeled off from the prepared pressure-sensitive adhesive tape, and various evaluations were performed. The results are shown in Table 1.

[0074] The components in Table 1 are as follows: Table 2 shows the SP values ​​of acryloylmorpholine, dimethylacrylamide, and acrylic acid, which are the polar group-containing polymerizable monomer (B). (Adhesive components) Olefin polymer: Product name "L-1253", manufactured by Kuraray Co., Ltd., hydrogenated polybutadiene having a (meth)acryloyl group at one end Tackifying resin 1: Product name "Arcon P140", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 140°C Tackifying resin 2: Product name "Arcon P100", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100°C Crosslinking agent: Product name "TEAI-1000", manufactured by Nippon Soda Co., Ltd. Photopolymerization initiator: 2,2-dimethoxy-2-phenylacetophenone (Substrate) Acrylic resin film: Product name "Soft Acrylic Sheet", manufactured by Tatsuta Chemical Co., Ltd. Fluorine-based resin film: Product name "50NS", manufactured by AGC Inc. PET film: Product name "Lumirror S10 (thickness 50 μm)" manufactured by Toray Industries, Inc.

[0075]

[0076] The pressure-sensitive adhesive tapes of Examples 1 to 9 had good peel resistance in low-temperature environments because the pressure-sensitive adhesive layer had a contact angle with water of 90 degrees or more. On the other hand, the pressure-sensitive adhesive tapes of Comparative Examples 1 and 2 had poor peel resistance in low-temperature environments because the pressure-sensitive adhesive layer had a contact angle with water of less than 90 degrees. Furthermore, when the pressure-sensitive adhesive tapes of Examples 1 to 9 were separately attached to steel materials and their anticorrosion performance was examined, the pressure-sensitive adhesive tapes of Examples 1 to 9 were also excellent in anticorrosion performance.

[0077] 10 Adhesive tape 11 Substrate 12, 13 Adhesive layer 14 Protective layer

Claims

1. An adhesive tape comprising a substrate and an adhesive layer provided on one surface of the substrate, wherein the adhesive layer is formed from an acrylic adhesive, the acrylic adhesive is an adhesive containing an acrylic polymer obtained by polymerizing a polymerizable monomer including a (meth)acrylic acid alkyl ester monomer (A), the thickness of the adhesive layer is 100 μm or more, and the contact angle of the adhesive layer with water is 90 degrees or more.

2. The adhesive tape according to claim 1, wherein the acrylic adhesive is a photocurable adhesive.

3. The adhesive tape according to claim 1, wherein the polymerizable monomer comprises a nitrogen-containing polymerizable monomer.

4. The adhesive tape according to claim 1, wherein the polymerizable monomer further comprises an olefin polymer.

5. The adhesive tape according to claim 1, wherein the polymerizable monomer does not contain a polar group-containing polymerizable monomer (B), or the polymerizable monomer contains a constituent unit derived from a polar group-containing polymerizable monomer (B) in a proportion of 15 parts by mass or less per 100 parts by mass of the constituent unit derived from the (meth)acrylic acid alkyl ester monomer (A).

6. The SP value of the polar group-containing polymerizable monomer (B) is 14 (cal / cm ３ ) １／２ The adhesive tape according to claim 5, wherein:

7. The adhesive tape according to claim 1, wherein the storage modulus (G') of the adhesive layer at 0°C is 200,000 Pa or more and 1,100,000 Pa or less.

8. The adhesive tape according to claim 1, wherein the substrate is at least one resin film selected from the group consisting of fluorine-based resin films, polyester-based resin films, acrylic-based resin films, and silicone-based resin films.

9. The adhesive tape according to claim 1, wherein the substrate is a fluorine-based resin film or an acrylic resin film.

10. The adhesive tape according to claim 1, wherein the thickness of the substrate is 20 μm or more and 300 μm or less.

11. The adhesive tape according to claim 1, which is for use on concrete or low-polarity substrates.

12. The adhesive tape according to claim 1, which is used for corrosion prevention.

13. A laminate comprising the pressure-sensitive adhesive tape according to claim 1 and a low-polarity adherend.

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