Adhesive tape and electronic device

Abstract

The present invention provides an adhesive tape having at least one adhesive layer. The adhesive layer contains at least one substance selected from the group consisting of an acrylic copolymer having a structural unit derived from a (meth)acrylic compound and an elastomer (E1) that is an elastomer other than an acrylic elastomer. The adhesive tape has a 180° peel strength against SUS of 8 N / 25 mm or more at 23°C. The adhesive tape is subjected to a compression test in which, in accordance with JIS K7171, a laminate formed by bonding aluminum alloy plates to both sides of the adhesive tape is compressed under the conditions of a temperature of 22 to 24°C, a humidity of 45 to 55%, and a compression speed of 0.05 mm / s, until a load of 50 N is reached. On an obtained stress-deformation curve, the slope (stress / deformation) of a regression line obtained using the least squares method for all data points falling within a stress range of 20 N to 50 N is 15.5 N / mm or more.

Description

Adhesive tape, and electronic devices

[0001] This invention relates to an adhesive tape. Furthermore, this invention relates to an electronic device including the adhesive tape.

[0002] Adhesive tapes having an adhesive layer containing an adhesive have been widely used for fixing components in various industrial applications such as electronic equipment, vehicles, housing, and building materials (for example, Patent Documents 1 to 3). Specifically, for example, adhesive tapes are used to adhere a cover panel for protecting the surface of portable electronic devices to a touch panel module or display panel module, or to adhere a touch panel module to a display panel module.

[0003] Japanese Patent Publication No. 2015-052050, Japanese Patent Publication No. 2015-021067, Japanese Patent Publication No. 2015-120876

[0004] In recent years, due to increased hygiene awareness, cleaning and disinfection with alcohol-based solvents are increasingly being used during the manufacturing process of devices. Therefore, adhesive tapes used to secure displays to casings in smartphones and tablets are required to exhibit excellent adhesive performance even when exposed to chemicals. However, with conventional adhesive tapes, exposure to chemical components such as alcohol can cause the chemicals to penetrate the adhesive layer, leading to peeling or a decrease in adhesive performance.

[0005] The present invention aims to provide an adhesive tape that can exhibit excellent adhesive performance even when exposed to chemicals. Furthermore, the present invention aims to provide an electronic device containing the adhesive tape.

[0006] Disclosure 1 is an adhesive tape having at least one adhesive layer, wherein the adhesive layer contains at least one selected from the group consisting of an acrylic copolymer having constituent units derived from a (meth)acrylic compound and an elastomer (E1) other than an acrylic elastomer, the adhesive tape has a 180° peel force of 8 N / 25 mm or more against SUS at 23°C, and the adhesive tape is subjected to a compression test in accordance with JIS K7171, in which a laminate formed by laminating aluminum alloy plates to both sides of the adhesive tape is compressed under conditions of a temperature of 22 to 24°C, a humidity of 45 to 55%, and a compression speed of 0.05 mm / s until the load reaches 50 N, and the slope of the regression line (stress / deformation) calculated using the least squares method for all data points in the stress-deformation curve obtained, where the stress is within the interval of 20 N to 50 N, is 15.5 N / mm or more. Disclosure 2 states that the above acrylic copolymer has an SP value of 9.45 (cal / cm³). ３ ) １／２ The following constituent units (a) derived from a (meth)acrylic compound are present, and the elastomer (E1) has an SP value of 9.45 (cal / cm³). ３ ) １／２ The adhesive tape of Disclosure 1 satisfies at least one of the following conditions: having a constituent unit (b) derived from the following compound. Disclosure 3 is the adhesive tape of Disclosure 2, wherein the adhesive layer contains the acrylic copolymer, and the acrylic copolymer has the constituent unit (a). Disclosure 4 is the adhesive tape of Disclosure 3, wherein the content of the constituent unit (a) in the acrylic copolymer is 30% by mass or more. Disclosure 5 is the constituent unit (a), with an SP value of 9.20 (cal / cm²). ３ ) １／２The adhesive tape of Disclosure 3 or 4 includes a constituent unit (a') derived from the following (meth)acrylic compound. Disclosure 6 is the adhesive tape of Disclosure 5, wherein the content of the constituent unit (a') in the acrylic copolymer is 5% by mass or more. Disclosure 7 is the adhesive tape of Disclosure 3, 4, 5, or 6, wherein the constituent unit (a) includes a constituent unit derived from an alkyl (meth)acrylate having an alkyl group with 12 or more carbon atoms. Disclosure 8 is the adhesive tape of Disclosure 3, 4, 5, 6, or 7, wherein the constituent unit (a) includes a constituent unit derived from a macromonomer having a number average molecular weight of 2,000 or more and 30,000 or less. Disclosure 9 is the adhesive tape of Disclosure 8, wherein the constituent unit (a) includes a constituent unit derived from an olefin polymer having a polymerizable unsaturated double bond at its terminal, and the content of the constituent unit derived from the olefin polymer having a polymerizable unsaturated double bond at its terminal in the acrylic polymer is 5% by mass or more and 30% by mass or less. Disclosure 10 is an adhesive tape according to Disclosures 2, 3, 4, 5, 6, 7, 8, or 9, wherein the adhesive layer contains the elastomer (E1), and the elastomer (E1) has the constituent unit (b). Disclosure 11 is an adhesive tape according to Disclosure 10, wherein the content ratio of the constituent unit (b) in the elastomer (E1) is 50% by mass or more. Disclosure 12 is an adhesive tape according to Disclosure 10, wherein the constituent unit (b) has an SP value of 9.20 (cal / cm²). ３ ) １／２The adhesive tape of the present disclosure 10 or 11 containing a structural unit (b') derived from the following compound. The present disclosure 13 is the adhesive tape of the present disclosure 12 in which the content ratio of the above structural unit (b') in the above elastomer (E1) is 50% by mass or more. The present disclosure 14 is the adhesive tape of the present disclosure 2, 3, 4, ３ ), １／２ and contains a structural unit (a') derived from a (meth)acrylic compound having an SP value of 9.20 (cal / cm ３ ), １／２ and the adhesive tape of the present disclosure 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 that contains a structural unit (b') derived from a compound having an SP value of 9.20 (cal / cm ３ ), １／２ and satisfies at least one of the following conditions: the total content ratio of the above structural unit (a') and the above structural unit (b') in the above adhesive layer is 20% by mass or more. The present disclosure 18 is the adhesive tape of the present disclosure 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 that contains a structural unit (a') derived from a (meth)acrylic compound having an SP value of 9.20 (cal / cm ３ ), １／２The adhesive tape of Disclosure 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 satisfies at least one of the following conditions: it contains a constituent unit (b') derived from a compound, and the total content ratio of the constituent unit (a') and the constituent unit (b') in the adhesive layer is 50% by mass or less. Disclosure 19 is an adhesive tape of Disclosure 19 in which the constituent unit (a) has an SP value of 9.20 (cal / cm²). ３ ) １／２ It contains the following constituent unit (a') derived from a (meth)acrylic compound, and the above constituent unit (b) has an SP value of 9.20 (cal / cm³). ３ ) １／２The adhesive tape of Disclosure 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 satisfies at least one of the following conditions, wherein the proportion of the constituent unit (a') in the total content ratio of the constituent unit (a') and the constituent unit (b') is 10% by mass or more. Disclosure 20 is the adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19, wherein the acrylic copolymer has constituent units derived from an alkyl (meth)acrylate having a linear or branched alkyl group with 6 to 8 carbon atoms. Disclosure 21 is an adhesive tape according to Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, in which the constituent units derived from the (meth)acrylic acid ester include a constituent unit having an aliphatic cyclic structure. Disclosure 22 is an adhesive tape according to Disclosure 21, in which the acrylic copolymer has a constituent unit derived from isobornyl methacrylate. Disclosure 23 is an adhesive tape according to Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22, in which the acrylic copolymer has a constituent unit derived from an alkyl (meth)acrylic acid ester whose glass transition temperature when homopolymerized is 0°C or higher. Disclosure 24 is an adhesive tape according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23, wherein the acrylic copolymer has constituent units derived from polar functional group-containing monomers, and the content of constituent units derived from polar functional group-containing monomers in the acrylic copolymer is 0.1% by mass or more.Disclosure 25 is an adhesive tape according to Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24, wherein the acrylic copolymer has constituent units derived from a vinyl aromatic compound, and the content of constituent units derived from the vinyl aromatic compound in the acrylic copolymer is 2.5% by mass or more and 15% by mass or less. Disclosure 26 is an adhesive tape according to Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25, wherein the acrylic copolymer has a weight-average molecular weight of 300,000 or more and 1,500,000 or less. Disclosure 27 is an adhesive tape according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, wherein the elastomer (E1) comprises at least one elastomer selected from styrene-based elastomers, olefin-based elastomers, and urethane-based elastomers. Disclosure 28 is an adhesive tape according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, or 27, wherein the adhesive layer contains the acrylic copolymer and the elastomer (E1), and the content of the elastomer (E1) is 60 parts by mass or less per 100 parts by mass of the acrylic copolymer. Disclosure 29 is an adhesive tape according to Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28, wherein the adhesive layer does not contain a tackifying resin, or the adhesive layer contains a tackifying resin, and the content of the tackifying resin is 50 parts by mass or less per 100 parts by mass of the acrylic copolymer. Disclosure 30 is an adhesive tape according to Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29, wherein the adhesive layer contains a coloring agent.Disclosure 31 is an adhesive tape according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30, wherein the adhesive layer has a bio-derived carbon content of 15% or more. Disclosure 32 is an adhesive tape according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or 31, wherein the adhesive layer has a bio-derived carbon content of 15% or more. Disclosure 33 is an adhesive tape according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, or 32, wherein the adhesive layer has a foamed structure, and the adhesive layer has bubbles derived from foamed particles. Disclosure 35 is an adhesive tape of Disclosure 34 in which the foaming particles contain thermally expandable microcapsules. Disclosure 36 is an adhesive tape of Disclosure 34 or 35 in which the foaming particles have an average particle size of 60 μm or less. Disclosure 37 is an adhesive tape of Disclosure 34, 35 or 36 in which the adhesive layer has an average major diameter of bubbles of 0.8 times or less the thickness of the adhesive layer. Disclosure 38 is an adhesive layer with a deemed density of 0.59 g / cm³. ３ 1.15g / cm or more ３The following are adhesive tapes according to Disclosure 34, 35, 36, or 37. Disclosure 39 is an adhesive tape according to Disclosure 34, 35, 36, 37, or 38, wherein the adhesive layer has a structure in which no air bubbles are exposed on the surface in the thickness direction. Disclosure 40 is an adhesive tape according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, or 39, consisting only of the adhesive layer. Disclosure 41 is an adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40 that does not have a base material. Disclosure 42 is an adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 or 39, wherein the adhesive layer has a foamed structure, and comprises the adhesive layer and a second adhesive layer that does not have a foamed structure on at least one side of the adhesive layer.Disclosure 44 describes an immersion test in which, after preparing a laminate by bonding the adhesive tape to SUS, the laminate is immersed for 48 hours in a mixed solution of isopropanol and water in a volume ratio of 7:3 at 65°C and 90% RH. The immersion test is performed on the adhesive tape before the chemical immersion test, where the 180° peel force against SUS at 23°C is compared to the 180° peel force at 65°C and 90% RH after standing for 48 hours at 65°C and 90% RH. The adhesive tape described above, according to disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, or 43, wherein the ratio of the 180° peel force to SUS at 23°C of the adhesive tape after a chemical immersion test with standing for a period of time is 25% or more. Disclosure 45 is an adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43 or 44 used for fixing internal components of electrical and electronic equipment or in-vehicle components. Disclosure 46 relates to electronic devices comprising adhesive tapes of Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45. The present invention will be described in detail below. Hereinafter, embodiments of the present invention or one thereof will be described as "this embodiment".

[0007] The inventors of the present invention investigated adjusting the 180° peel force of the adhesive tape against SUS (stainless steel) at 23°C to a specific value or higher, and ensuring that the slope of the straight line calculated after a specific compression test on the adhesive tape is also a specific value or higher. As a result, they found that it is possible to obtain an adhesive tape that can exhibit excellent adhesive performance even when exposed to chemicals, thus completing the present invention.

[0008] The adhesive tape of this embodiment has a lower limit of 8 N / 25 mm for 180° peel force against SUS at 23°C. Because the adhesive layer has excellent adhesion due to the 180° peel force of the adhesive tape against SUS at 23°C being 8 N / 25 mm or higher, the adhesion between the adhesive tape and the adherend is improved. Therefore, by setting the 180° peel force of the adhesive tape against SUS at 23°C and the slope of the straight line in the compression test of the adhesive tape (described later) to a specific value or higher, chemical components such as alcohol are less likely to penetrate the adhesive interface between the adhesive tape and the adherend, thus preventing chemical components from penetrating the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A preferred lower limit for the 180° peel force of the adhesive tape against SUS at 23°C is 10 N / 25 mm, a more preferred lower limit is 15 N / 25 mm, and an even more preferred lower limit is 20 N / 25 mm. Furthermore, there is no specific upper limit to the 180° peel force of the above adhesive tape against SUS at 23°C, but approximately 50 N / 25 mm is a practical upper limit. Examples of the 180° peel force of the above adhesive tape against SUS at 23°C include 8 N / 25 mm to 50 N / 25 mm, 10 N / 25 mm to 50 N / 25 mm, 15 N / 15 mm to 50 N / 25 mm, 20 N / 25 mm to 50 N / 25 mm, etc.

[0009] The 180° peel force of the above adhesive tape against SUS at 23°C can be measured by the following method. First, if necessary, a 23 μm thick polyethylene terephthalate film is pressed and backed onto the adhesive layer on one side of the adhesive tape (the side not to be measured) by running a 2 kg rubber roller back and forth once at a speed of 300 mm / min in an environment of 23°C and 50% RH. Next, a test piece prepared by cutting to a width of 25 mm and a length of 75 mm is attached to a SUS304 plate (a SUS304 plate that has been washed with ethanol and then wiped dry), pressed onto it by running a 2 kg rubber roller back and forth once at a speed of 300 mm / min in an environment of 23°C and 50% RH, and then cured for 20 minutes in an environment of 23°C and 50% RH to prepare a test sample. The obtained test samples can be measured by peeling the test piece from the SUS304 plate under the conditions of 23°C, 50% RH, tensile speed of 300 mm / min, and peel angle of 180°, in accordance with JIS Z0237:2009.

[0010] Methods for adjusting the 180° peel strength of the above adhesive tape against SUS at 23°C include, for example, changing the composition of the acrylic copolymer contained in the adhesive layer (for example, increasing the content of constituent units derived from polar functional group-containing monomers), adjusting the weight-average molecular weight, polydispersity, etc., of the acrylic copolymer, including a tackifying resin in the adhesive layer, adjusting the thickness of the adhesive layer, adjusting the content of the crosslinking agent contained in the adhesive composition, and adjusting the type and thickness of the substrate.

[0011] In this embodiment, the adhesive tape is subjected to a compression test in accordance with JIS K7171, where an aluminum alloy plate is bonded to both sides of the adhesive tape, and the laminate is compressed until the load reaches 50 N under conditions of a temperature of 22 to 24°C, a humidity of 45 to 55%, and a compression speed of 0.05 mm / s. The slope of the regression line (stress / deformation) is calculated using the least squares method for all data points on the obtained stress-deformation curve where the stress falls within the interval of 20 N to 50 N. The lower limit of the slope of the line (hereinafter sometimes simply referred to as "slope of the line in the compression test of the adhesive tape") is 15.5 N / mm. A slope of the line in the compression test of the adhesive tape of 15.5 N / mm or higher improves the bending rigidity of this embodiment, resulting in an adhesive tape with excellent adhesion to the adherend. Therefore, in this embodiment, by setting the 180° peel strength of the adhesive layer against SUS at 23°C and the slope of the line in the compression test of the adhesive tape to a specific value or higher, it becomes difficult for chemical components such as alcohol to penetrate into the adhesive interface between the adhesive tape and the adherend, thereby making it difficult for chemical components to penetrate into the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. The preferred lower limit of the slope of the line in the compression test of the adhesive tape is 16.5 N / mm, a more preferred lower limit is 17.5 N / mm, and an even more preferred lower limit is 18.5 N / mm. The preferred upper limit of the slope of the line in the compression test of the adhesive tape is 40.0 N / mm. By setting the slope of the line in the compression test of the adhesive tape to 40.0 N / mm or less, the adhesive tape of this embodiment can exhibit excellent adhesive performance. The more preferred upper limit of the slope of the line in the compression test of the adhesive tape is 30.0 N / mm, and an even more preferred upper limit is 25.0 N / mm. Examples of the linear slope in the compression test of the adhesive tape mentioned above include 15.5 N / mm to 40.0 N / mm, 16.5 N / mm to 30.0 N / mm, 17.5 N / mm to 25.0 N / mm, and 18.5 N / mm to 25.0 N / mm.

[0012] The slope of the straight line in the compression test of the above adhesive tape can be obtained by the following method. Figure 1 schematically shows the test method of the compression test. Specifically, first, aluminum alloy plates (SHAANXISHEW-ESTEELPIPE, "Aluminum 6061-T6", thickness 1.6 mm, width 25.4 mm, length 203.2 mm) are bonded to both sides of the adhesive tape of this embodiment by applying a load of 1 MPa for 20 seconds in an environment of 65°C to laminate and integrate them, and then the laminate is produced by curing it by leaving it undisturbed for 24 hours in an environment of 23°C. Next, the fabricated laminate 1 is set up in a Tensilon (manufactured by A&D Co., Ltd.) used as a measuring instrument in accordance with JIS K7171, as shown in Figure 1 (distance between compression jigs: 57.15 mm, distance between fixing jigs: 177.8 mm). Then, a compression test is performed on the laminate 1 under the conditions of a temperature of 22-24°C, a humidity of 45-55%, and a compression speed of 0.05 mm / s, until the load reaches 50 N. After the compression test is performed, the slope of the regression line (stress / deformation) is calculated using the least squares method for all data points in the stress-deformation curve obtained, where the stress on the stress-deformation curve falls within the interval of 20 N to 50 N. This allows us to obtain the slope of the line in the compression test of the adhesive tape described above.

[0013] Methods for adjusting the slope of the straight line in the compression test of the above adhesive tape include, for example, raising the glass transition temperature of the adhesive layer or including additives such as fillers in the adhesive layer.

[0014] The adhesive tape of this embodiment has at least one adhesive layer. The adhesive layer contains at least one selected from the group consisting of acrylic copolymers having structural units derived from (meth)acrylic compounds and elastomers other than acrylic elastomers (E1). Note that the acrylic copolymer having structural units derived from vinyl aromatic compounds is included in the acrylic elastomer. In this specification, "(meth)acrylic" means acrylic or methacrylic. In this specification, "(meth)acrylic compound" means a compound having a (meth)acryloyl group. Furthermore, in this specification, "(meth)acryloyl" means acryloyl or methacryloyl.

[0015] In the adhesive tape of this embodiment, the acrylic copolymer has an SP value of 9.45 (cal / cm²). ３ ) １／２ The following constituent units (a) derived from a (meth)acrylic compound are present, and the elastomer (E1) has an SP value of 9.45 (cal / cm³). ３ ) １／２It is preferable that the adhesive tape of this embodiment satisfies at least one of the following conditions: having a constituent unit (b) derived from a compound. In the adhesive tape of this embodiment, the acrylic copolymer and the elastomer (E1) having such a constituent unit further reduces the polarity of the adhesive layer and makes it more difficult for chemical components to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. In particular, from the viewpoint of the adhesive tape of this embodiment being able to easily maintain excellent adhesive performance, it is preferable that the adhesive layer contains the acrylic copolymer and that the acrylic copolymer has the constituent unit (a). Furthermore, from the viewpoint of the adhesive tape of this embodiment being able to easily prevent the penetration of chemical components, it is preferable that the adhesive layer contains the elastomer (E1) and that the elastomer (E1) has the constituent unit (b). Furthermore, from the viewpoint of achieving an excellent balance between the adhesive performance and chemical resistance of the adhesive tape of this embodiment, it is preferable that the adhesive layer contains the acrylic copolymer and the elastomer (E1), the acrylic copolymer has the constituent unit (a), and the elastomer (E1) has the constituent unit (b).

[0016] A preferred lower limit for the content of the above-mentioned structural unit (a) in the above-mentioned acrylic copolymer is 30% by mass. When the content of the above-mentioned structural unit (a) is 30% by mass or more, the polarity of the adhesive layer is further reduced, and chemical components become less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferred lower limit for the content of the above-mentioned structural unit (a) in the above-mentioned acrylic copolymer is 40% by mass, and an even more preferred lower limit is 45% by mass. Furthermore, a preferred upper limit for the content of the above-mentioned structural unit (a) in the above-mentioned acrylic copolymer is 99% by mass. When the content of the above-mentioned structural unit (a) is 99% by mass or less, the adhesive tape of this embodiment has excellent adhesive performance. A more preferred upper limit for the content of the above-mentioned structural unit (a) is 97% by mass, and an even more preferred upper limit is 95% by mass. Examples of the content ratio of the above-mentioned constituent unit (a) in the above-mentioned acrylic copolymer include 30% by mass or more and 99% by mass or less, 40% by mass or more and 97% by mass or less, 45% by mass or more and 95% by mass or less, etc.

[0017] The SP value of the (meth)acrylic compound in the above constituent unit (a) is 9.45 (cal / cm³). ３ ) １／２ The following is acceptable, but the preferred upper limit is 9.30 (cal / cm³). ３ ) １／２ The SP value of the above (meth)acrylic compound is 9.30 (cal / cm³). ３ ) １／２ As a result, the polarity of the adhesive layer is further reduced, and chemical components are less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferable upper limit for the SP value of the (meth)acrylic compound (a) is 9.20 (cal / cm²). ３ ) １／２ A more preferable upper limit is 8.50 (cal / cm³). ３ ) １／２ A more preferable upper limit is 8.40 (cal / cm³). ３ ) １／２In particular, from the viewpoint that the adhesive tape of this embodiment can exhibit even better adhesive performance when exposed to chemicals, the above-mentioned component unit (a) has an SP value of 9.20 (cal / cm²). ３ ) １／２ It is preferable that the (meth)acrylic compound (a) contains the following constituent unit (a'). There is no particular lower limit to the SP value of the (meth)acrylic compound (a), but 8.35 (cal / cm³) is preferable. ３ ) １／２ This degree represents the practical lower limit. For example, the SP value of the (meth)acrylic compound in the above constituent unit (a) is 8.35 (cal / cm³). ３ ) １／２ 9.30 (cal / cm) ３ ) １／２ Below, 8.35 (cal / cm ３ ) １／２ More than 9.20 (cal / cm ３ ) １／２ Below, 8.35 (cal / cm ３ ) １／２ More than 8.50 (cal / cm ３ ) １／２ Below, 8.35 (cal / cm ３ ) １／２ 8.40 (cal / cm) ３ ) １／２ The following are some examples.

[0018] In this specification, "SP value" is also called the solubility parameter and is an index that can represent the ease of solubility, calculated using the Fedors method (R.F. Fedors, Polym. Eng. Sci., 14(2), 147-154 (1974)) (unit = (cal / cm³) ３ ) １／２ ).

[0019] In the above acrylic copolymer, the preferred lower limit for the content of the constituent unit derived from the above constituent unit (a') is 5% by mass. When the content of the constituent unit derived from the above constituent unit (a') is 5% by mass or more, the polarity of the adhesive layer is further reduced, and chemical components become less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferred lower limit for the content of the constituent unit derived from the above constituent unit (a') in the above acrylic copolymer is 7% by mass, and an even more preferred lower limit is 10% by mass. Furthermore, a preferred upper limit for the content of the constituent unit derived from the above constituent unit (a') in the above acrylic copolymer is 85% by mass. When the content of the constituent unit derived from the above constituent unit (a') in the above acrylic copolymer is 85% by mass or less, the bending rigidity of the adhesive tape of this embodiment is further improved, resulting in a tape with better deformation resistance, and thus it can exhibit better adhesive performance even when exposed to chemicals. A more preferable upper limit for the content of the constituent unit derived from the constituent unit (a') in the above acrylic copolymer is 75% by mass, and an even more preferable upper limit is 65% by mass. Examples of the content of the constituent unit derived from the constituent unit (a') in the above acrylic copolymer include 5% by mass or more and 85% by mass or less, 7% by mass or more and 75% by mass or less, 10% by mass or more and 65% by mass or less, etc.

[0020] The above acrylic copolymer preferably includes, as the above-mentioned structural unit (a), a structural unit derived from an alkyl (meth)acrylate having an alkyl group with 12 or more carbon atoms, from the viewpoint of increasing the free volume of the acrylic copolymer. Furthermore, from the viewpoint of further improving the cohesive force between the side chains in the above acrylic copolymer, the alkyl (meth)acrylate having an alkyl group with 12 or more carbon atoms preferably includes an alkyl (meth)acrylate having an alkyl group with 130 or fewer carbon atoms.

[0021] Examples of alkyl (meth)acrylate esters having 12 or more C12 include lauryl acrylate (SP value: 9.15 (cal / cm³)).３ ) １／２ ), isostearyl acrylate (SP value: 8.46 (cal / cm³) ３ ) １／２ Examples of constituent units derived from ) etc.

[0022] When the above acrylic copolymer contains structural units derived from an alkyl (meth)acrylate having an alkyl group having 12 or more carbon atoms, the preferred lower limit of the content of structural units derived from the alkyl (meth)acrylate having an alkyl group having 12 or more carbon atoms in the above acrylic copolymer is 4% by mass, and the preferred upper limit is 50% by mass. By having a content of 4% by mass or more of structural units derived from the alkyl (meth)acrylate having an alkyl group having 12 or more carbon atoms, the adhesive tape of this embodiment will have superior adhesive performance. By having a content of 50% by mass or less of structural units derived from the alkyl (meth)acrylate having an alkyl group having 12 or more carbon atoms, the bending rigidity of the adhesive tape of this embodiment will be further improved, resulting in a tape with superior deformation resistance, and thus enabling it to exhibit superior adhesive performance even when exposed to chemicals. A more preferred lower limit of the content of structural units derived from the alkyl (meth)acrylate having an alkyl group having 12 or more carbon atoms is 6% by mass, a more preferred upper limit is 45% by mass, an even more preferred lower limit is 8% by mass, and an even more preferred upper limit is 40% by mass. Examples of the content of constituent units derived from alkyl (meth)acrylate esters having an alkyl group with 12 or more carbon atoms include 4% by mass or more and 50% by mass or less, 6% by mass or more and 45% by mass or less, and 8% by mass or more and 40% by mass or less.

[0023] The above acrylic copolymer preferably includes, as the above-mentioned structural unit (a), a structural unit derived from a macromonomer having a (meth)acryloyl group and a number average molecular weight of 2,000 to 30,000, from the viewpoint of increasing the free volume of the acrylic copolymer and facilitating aggregation between side chains.

[0024] The number average molecular weight of the macromonomer having the (meth)acryloyl group described above and having a number average molecular weight of 2,000 to 30,000 is not particularly limited as long as it is between 2,000 and 30,000. However, from the viewpoint of increasing the free volume of the acrylic copolymer and facilitating aggregation between side chains, a preferred lower limit is 4,000, a preferred upper limit is 25,000, a more preferred lower limit is 5,000, and a more preferred upper limit is 23,000. Examples of the number average molecular weight of the macromonomer having the (meth)acryloyl group described above and having a number average molecular weight of 2,000 to 30,000 include 4,000 to 25,000 and 5,000 to 23,000. In this specification, "weight average molecular weight" and "number average molecular weight" refer to the weight average molecular weight and number average molecular weight measured as polystyrene-equivalent molecular weight by gel permeation chromatography (GPC). For example, the weight-average molecular weight and number-average molecular weight can be measured using a Waters "2690 Separations Module" as the measuring instrument and a Showa Denko "GPCKF-806L" as the column, under conditions of a sample flow rate of 1 mL / min and a column temperature of 40°C.

[0025] Examples of macromonomers having (meth)acryloyl groups and a number-average molecular weight of 2,000 to 30,000 include styrene polymers having (meth)acryloyl groups at the terminals and olefin polymers having (meth)acryloyl groups at the terminals. In particular, from the viewpoint of further reducing the polarity of the adhesive layer, it is preferable to include olefin polymers having (meth)acryloyl groups at the terminals.

[0026] Furthermore, it is preferable that the above acrylic copolymer has, as constituent units derived from the above (meth)acrylic compound, constituent units derived from alkyl (meth)acrylate ester and constituent units derived from an olefin polymer having a (meth)acryloyl group at its terminal. When the above acrylic copolymer has such a configuration, the above acrylic copolymer has a structure in which constituent units derived from alkyl acrylate ester are the main chain and constituent units derived from an olefin polymer having a (meth)acryloyl group at its terminal are the side chains. In this structure, the constituent units derived from the olefin polymer having a (meth)acryloyl group at its terminal, located in the side chains of the above acrylic copolymer, aggregate through interaction and form a pseudo-crosslink. Therefore, when the above acrylic copolymer has this structure, when the strain is small, the molecules of the above acrylic copolymer become hard as if they were in a crosslinked structure due to the above-mentioned pseudo-crosslink, and the adhesive layer has appropriate hardness. As a result, the bending rigidity of the adhesive tape of this embodiment is further improved. Furthermore, when the strain applied to the adhesive layer is small, the cohesive force of the adhesive layer is further improved, and the adhesive strength of the adhesive tape of this embodiment is further improved.

[0027] When the adhesive layer is subjected to impact and the strain increases, the pseudo-crosslinking breaks, making the molecules of the acrylic copolymer more stretchable. As a result, the adhesive layer becomes more flexible and exhibits excellent stress relaxation properties. Therefore, the adhesive tape of this embodiment has superior shock absorption properties and is more suitable for use in fixing internal components of electrical and electronic equipment or automotive components.

[0028] The olefin polymer having a (meth)acryloyl group at one end may have a (meth)acryloyl group at one end or at both ends. In particular, an olefin polymer having a (meth)acryloyl group at one end is preferred because it is less prone to intramolecular chemical crosslinking, increases the cohesive force of the adhesive layer, and provides appropriate hardness, thereby further improving the bending rigidity of the adhesive tape of this embodiment.

[0029] Examples of olefin polymers having the (meth)acryloyl group include ethylene macromonomers having a (meth)acryloyl group at one end, propylene macromonomers having a (meth)acryloyl group at one end, ethylene-butylene macromonomers having a (meth)acryloyl group at one end, and ethylene-propylene macromonomers having a (meth)acryloyl group at one end. Among these, ethylene-butylene macromonomers having a (meth)acryloyl group at one end are preferred from the viewpoint of facilitating aggregation between the side chains of the acrylic copolymer.

[0030] When the above acrylic copolymer has the above (meth)acryloyl group and is derived from a macromonomer having a number average molecular weight of 2,000 to 30,000, and as a constituent unit derived from an olefin polymer having a (meth)acryloyl group at its end, the preferred lower limit of the content of the constituent unit derived from the olefin polymer having a (meth)acryloyl group at its end in the above acrylic copolymer is 5% by mass, and the preferred upper limit is 30% by mass. By having a content of 5% by mass or more of the constituent unit derived from the olefin polymer having a (meth)acryloyl group at its end, an appropriate number of pseudo-crosslinks are formed. As a result, the adhesive layer has an appropriate hardness, and the bending rigidity of the adhesive tape of this embodiment is further improved. By having a content of 30% by mass or less of the constituent unit derived from the olefin polymer having a (meth)acryloyl group at its end, the adhesive layer has an appropriate flexibility, and the shock absorption of the resulting adhesive tape is further improved, making it more suitable for fixing internal components of electrical and electronic equipment or automotive components. A more preferable lower limit for the content of constituent units derived from the olefin polymer having (meth)acryloyl groups at the terminals is 8% by mass, a more preferable upper limit is 25% by mass, an even more preferable lower limit is 10% by mass, and an even more preferable upper limit is 20% by mass. Examples of the content of constituent units derived from the olefin polymer having (meth)acryloyl groups at the terminals include 5% by mass or more and 30% by mass or less, 8% by mass or more and 25% by mass or less, 10% by mass or more and 20% by mass or less, etc.

[0031] A macromonomer having the above-mentioned (meth)acryloyl group and having a number-average molecular weight of 2,000 to 30,000 is specifically, for example, HPVM-L-1253 (ethylene-butylene macromonomer having a (meth)acryloyl group at one end, manufactured by Kraton Polymers, SP value: 8.31 (cal / cm³) ３ ) １／２ Examples include:

[0032] The constituent units derived from the above (meth)acrylic compound may include constituent units derived from alkyl (meth)acrylate esters having an alkyl group with 11 or fewer carbon atoms. Furthermore, the above acrylic compound may have a constituent unit (a) derived from alkyl (meth)acrylate esters having an alkyl group with 11 or fewer carbon atoms.

[0033] Examples of alkyl (meth)acrylate esters having an alkyl group with 11 or fewer carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, n-hexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, 1-methylheptyl (meth)acrylate, isooctyl (meth)acrylate, and n-nonyl (meth)acrylate. In particular, from the viewpoint of enabling the adhesive layer to exhibit adhesive strength to various materials and further improving the handling of the adhesive tape of this embodiment, it is preferable that the acrylic compound contains an alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms. Furthermore, from the viewpoint of further preventing the penetration of chemical components into the adhesive layer, it is even more preferable that the acrylic compound contains an alkyl (meth)acrylate having a linear or branched alkyl group having 6 to 8 carbon atoms.

[0034] When the above acrylic copolymer contains structural units derived from an alkyl (meth)acrylate having a linear or branched alkyl group having 6 to 8 carbon atoms, the preferred lower limit of the content of structural units derived from the alkyl (meth)acrylate having a linear or branched alkyl group having 6 to 8 carbon atoms in the above acrylic copolymer is 10% by mass, and the preferred upper limit is 70% by mass. The bending rigidity of the adhesive tape of this embodiment is further improved by having the content of structural units derived from the alkyl (meth)acrylate having a linear or branched alkyl group having 6 to 8 carbon atoms within the above range. A more preferred lower limit of the content of structural units derived from the alkyl (meth)acrylate having a linear or branched alkyl group having 6 to 8 carbon atoms is 20% by mass, a more preferred upper limit is 65% by mass, an even more preferred lower limit is 30% by mass, an even more preferred upper limit is 60% by mass, and an even more preferred upper limit is 50% by mass. Examples of the content of constituent units derived from alkyl (meth)acrylate having linear or branched alkyl groups with 6 to 8 carbon atoms include 10% to 70% by mass, 20% to 65% by mass, 30% to 60% by mass, and 30% to 50% by mass.

[0035] The constituent units derived from the above (meth)acrylic compound may include constituent units derived from alkyl (meth)acrylate ester having the above-mentioned alkyl group having an aliphatic cyclic structure. By including the above-mentioned alkyl copolymer, as a constituent unit derived from the above (meth)acrylic compound, the bending rigidity of the adhesive tape of this embodiment is further improved. Furthermore, the above-mentioned (meth)acrylic compound may also include the above-mentioned constituent unit (a), which is derived from alkyl (meth)acrylate ester having the above-mentioned alkyl group having an aliphatic cyclic structure.

[0036] Examples of constituent units derived from alkyl (meth)acrylate esters having an aliphatic cyclic structure include cyclohexyl (meth)acrylate and isobornyl (meth)acrylate, and among these, constituent units derived from isobornyl methacrylate are preferred from the viewpoint of further improving the bending rigidity of the adhesive tape of this embodiment.

[0037] When the above acrylic copolymer contains structural units derived from an alkyl (meth)acrylate having an alkyl group having an aliphatic cyclic structure, the preferred lower limit of the content of structural units derived from the alkyl (meth)acrylate having an alkyl group having an aliphatic cyclic structure in the acrylic copolymer is 5% by mass, and the preferred upper limit is 50% by mass. By having the content of structural units derived from the alkyl (meth)acrylate having an alkyl group having an aliphatic cyclic structure within the above range, the bending rigidity of the adhesive tape of this embodiment is further improved. A more preferred lower limit of the content of structural units derived from the alkyl (meth)acrylate having an alkyl group having an aliphatic cyclic structure is 8% by mass, a more preferred upper limit is 40% by mass, an even more preferred lower limit is 10% by mass, an even more preferred upper limit is 30% by mass, and an even more preferred lower limit is 20% by mass. Examples of the content of constituent units derived from alkyl (meth)acrylate having an alkyl group having the above-mentioned aliphatic cyclic structure include 5% to 50% by mass, 8% to 40% by mass, 10% to 30% by mass, 20% to 30% by mass, and so on.

[0038] The above acrylic copolymer preferably has a constituent unit derived from an alkyl (meth)acrylate ester whose glass transition temperature (hereinafter sometimes referred to as "homopolymer Tg") when it is a homopolymer is 0°C or higher. The bending rigidity of the adhesive tape is further improved when the above acrylic copolymer has a constituent unit derived from an alkyl (meth)acrylate ester whose glass transition temperature when it is a homopolymer is 0°C or higher as a constituent unit derived from the above acrylic compound. In this specification, "glass transition temperature when it is a homopolymer" means the glass transition temperature measured by dynamic viscoelasticity measurement of a homopolymer when the weight-average molecular weight of the (meth)acrylate ester is 100,000 to 2,000,000. More specifically, the homopolymer Tg can be measured by performing dynamic viscoelasticity measurement using a dynamic viscoelasticity measuring device (such as "DVA-200" manufactured by IT Measuring Instruments Co., Ltd.) under the conditions of a measurement frequency of 1 Hz, a measurement temperature of -100°C to 200°C, and a heating rate of 10°C / min. Generally speaking, if the weight-average molecular weight is between 100,000 and 2,000,000, the homopolymer Tg does not depend on the weight-average molecular weight.

[0039] In the alkyl (meth)acrylate ester described above, where the homopolymer Tg is 0°C or higher, the homopolymer Tg may be 0°C or higher, but a preferred lower limit is 20°C. A homopolymer Tg of 20°C or higher results in superior bending rigidity of the adhesive tape of this embodiment. A more preferred lower limit for the homopolymer Tg is 50°C. Furthermore, from the viewpoint of enabling the adhesive tape of this embodiment to exhibit superior adhesive performance, a preferred upper limit for the homopolymer Tg is 200°C, and a more preferred upper limit is 185°C. Examples of the homopolymer Tg include 20°C to 200°C, 50°C to 185°C, etc.

[0040] Examples of alkyl (meth)acrylate esters having a homopolymer Tg of 0°C or higher include isobornyl methacrylate (homopolymer Tg: 180°C), isobornyl acrylate (homopolymer Tg: 97°C), methyl acrylate (homopolymer Tg: 8°C), and methyl methacrylate (homopolymer Tg: 105°C). Among these, isobornyl methacrylate is preferred from the viewpoint that, as a result of a larger free volume of the acrylic copolymer, the adhesive tape of this embodiment is more likely to maintain superior bending rigidity while also having superior adhesive performance.

[0041] The above acrylic copolymer preferably has structural units derived from polar functional group-containing monomers. By having structural units derived from polar functional group-containing monomers as structural units derived from the (meth)acrylic compound, the acrylic copolymer can sufficiently form a crosslinked structure through chemical crosslinking via a crosslinking agent between molecules, and the cohesive force of the adhesive layer is further increased because the polar functional groups in the acrylic copolymer interact with each other. As a result, the adhesive layer has a more appropriate hardness, and the bending rigidity of the adhesive tape of this embodiment is further improved. In addition, the acrylic copolymer may have structural units derived from polar functional group-containing monomers as structural unit (a).

[0042] Examples of the polar functional group-containing monomers include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, and amino group-containing monomers. In particular, from the viewpoint of further increasing the cohesive strength of the adhesive layer, it is preferable that the polar functional group-containing monomers include at least one selected from the group consisting of carboxyl group-containing monomers and hydroxyl group-containing monomers.

[0043] Examples of the above carboxyl group-containing monomers include unsaturated monocarboxylic acids such as (meth)acrylic acid, (meth)acryloylacetic acid, (meth)acryloylpropionic acid, (meth)acryloylbutyric acid, (meth)acryloylpentanoic acid, and crotonic acid, as well as dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid. Examples of the above hydroxyl group-containing monomers include 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. Examples of the above amide group-containing monomers include N-vinyl-2-pyrrolidone, N,N-dimethyl(meth)acrylamide, and N-isopropyl(meth)acrylamide. Examples of the above amino group-containing monomers include (meth)acryloylmorpholine, dimethylaminoethyl (meth)acrylate, and diethylaminoethyl (meth)acrylate.

[0044] In the above acrylic copolymer, the preferred lower limit for the content of constituent units derived from the polar functional group-containing monomer is 0.1% by mass, and the preferred upper limit is 10% by mass. When the content of constituent units derived from the polar functional group-containing monomer is 0.1% by mass or more, the cohesive force of the adhesive layer is increased, and the adhesive layer has a more appropriate hardness, thus improving the bending rigidity of the adhesive tape of this embodiment. When the content of constituent units derived from the polar functional group-containing monomer is 10% by mass or less, the adhesive layer has an appropriate flexibility, thus improving the adhesive strength of the adhesive tape of this embodiment. A more preferred lower limit for the content of constituent units derived from the polar functional group-containing monomer is 1.0% by mass, a more preferred upper limit is 9.0% by mass, an even more preferred lower limit is 3.0% by mass, an even more preferred upper limit is 8.0% by mass, an even more preferred lower limit is 5.0% by mass, and an even more preferred upper limit is 7.0% by mass. Examples of the content ratio of constituent units derived from the above polar functional group-containing monomers include 0.1% by mass or more and 10% by mass or less, 1.0% by mass or more and 9.0% by mass or less, 3.0% by mass or more and 8.0% by mass or less, and 5.0% by mass or more and 7.0% by mass or less.

[0045] In recent years, the depletion of petroleum resources and the emission of carbon dioxide from the combustion of petroleum-derived products have become serious concerns. Therefore, attempts are being made to conserve petroleum resources by using bio-derived materials instead of petroleum-derived materials. For this reason, the (meth)acrylic compound in the constituent unit derived from the (meth)acrylic compound described above may consist only of petroleum-derived materials, but it is preferable that it also contains bio-derived materials that include bio-derived carbon. The inclusion of bio-derived materials in the (meth)acrylic compound is preferable from the standpoint of conserving petroleum resources, and furthermore, since bio-derived materials are originally produced by taking in carbon dioxide from the atmosphere, it is thought that burning them will not increase the total amount of carbon dioxide in the atmosphere, which is also preferable from the standpoint of reducing carbon dioxide emissions.

[0046] When the (meth)acrylic compound in the constituent unit derived from the above-mentioned (meth)acrylic compound contains a bio-derived material, examples of (meth)acrylic compounds containing a bio-derived material include alkyl (meth)acrylates synthesized by esterification of an alcohol, which is a bio-derived material, with (meth)acrylic acid.

[0047] The above acrylic copolymer may have structural units other than those derived from the above (meth)acrylic compound.

[0048] The above-mentioned acrylic copolymer preferably has constituent units derived from a vinyl aromatic compound as constituent units other than those derived from the (meth)acrylic compound. By having constituent units derived from a vinyl aromatic compound in the above-mentioned acrylic copolymer, the adhesive tape of this embodiment exhibits superior shock absorption and is more suitably used for fixing internal components of electrical and electronic equipment or automotive components.

[0049] Examples of constituent units derived from the above-mentioned vinyl aromatic compounds include constituent units derived from styrene, constituent units derived from α-methylstyrene, and constituent units derived from their hydrogenated products. Among these, constituent units derived from styrene are preferred from the viewpoint of easily achieving both shock absorption and bending rigidity in the resulting adhesive tape. Note that the constituent units derived from these vinyl aromatic compounds may consist of only one type, or two or more types may coexist.

[0050] When the above acrylic copolymer has structural units derived from a vinyl aromatic compound, the above acrylic copolymer may be a random copolymer, or it may be a block copolymer (hereinafter sometimes simply referred to as "block copolymer (A)") of a block having structural units derived from a (meth)acrylic acid ester having a hydrocarbon group (hereinafter sometimes simply referred to as "block (A-2)") and a block having structural units derived from a vinyl aromatic compound (hereinafter sometimes simply referred to as "block (A-1)"). In the above block copolymer (A), block (A-1) becomes a hard segment (hard block) and block (A-2) becomes a soft segment (soft block), imparting shock absorption to the adhesive tape. In particular, from the viewpoint of obtaining an adhesive tape with superior shock absorption, it is preferable that the above acrylic copolymer includes block copolymer (A) when it has structural units derived from a vinyl aromatic compound.

[0051] The block copolymer (A) may be a diblock copolymer or a triblock copolymer. Among these, a triblock copolymer is preferred from the viewpoint of achieving both shock absorption and bending resistance of the resulting adhesive tape, and among triblock copolymers, a triblock copolymer having the structure of block (A-1) - block (A-2) - block (A-1) is more preferred.

[0052] The preferred lower limit for the content of block (A-1) in the block copolymer (A) is 3% by mass, and the preferred upper limit is 15% by mass. When the content of block (A-1) is 3% by mass or more, the adhesive tape of this embodiment has superior shock absorption properties. When the content of block (A-1) is 15% by mass or less, the adhesive tape of this embodiment has superior adhesive strength. The more preferred lower limit for the content of block (A-1) is 5% by mass, and the more preferred upper limit is 12% by mass. Examples of the content of block (A-1) include 3% by mass or more and 15% by mass or less, and 5% by mass or more and 12% by mass or less.

[0053] In the above acrylic copolymer, the preferred lower limit of the content of constituent units derived from the vinyl aromatic compound is 2.5% by mass, and the preferred upper limit of the content of constituent units derived from the vinyl aromatic compound is 15% by mass. By having the content of constituent units derived from the vinyl aromatic compound within the above range, the adhesive tape of this embodiment is more likely to provide better shock absorption while maintaining better bending rigidity. A more preferred lower limit of the content of constituent units derived from the vinyl aromatic compound is 3.0% by mass, a more preferred upper limit is 12% by mass, an even more preferred lower limit is 3.5% by mass, an even more preferred upper limit is 10% by mass, an even more preferred lower limit is 4.5% by mass, an even more preferred upper limit is 8.0% by mass, and a particularly preferred lower limit is 6.0% by mass. Examples of the content ratio of constituent units derived from the vinyl aromatic compound include 2.5% by mass or more and 15% by mass or less, 3.0% by mass or more and 12% by mass or less, 3.5% by mass or more and 10% by mass or less, 4.5% by mass or more and 8.0% by mass or less, and 6.0% by mass or more and 8.0% by mass or less.

[0054] The weight-average molecular weight (Mw) of the above acrylic copolymer has a preferred lower limit of 300,000 and a preferred upper limit of 1,500,000. Having the weight-average molecular weight (Mw) of the above acrylic copolymer within this range increases the cohesive force of the adhesive layer, thereby further improving the bending rigidity of the adhesive tape of this embodiment. A more preferred lower limit for the weight-average molecular weight (Mw) of the above acrylic copolymer is 500,000, a more preferred upper limit is 1,200,000, an even more preferred lower limit is 600,000, an even more preferred upper limit is 1,000,000, and an even more preferred lower limit is 800,000. Examples of weight-average molecular weight (Mw) of the above acrylic copolymer include 300,000 to 1,500,000, 500,000 to 1,200,000, 600,000 to 1,000,000, and 800,000 to 1,000,000.

[0055] The polydispersity (weight-average molecular weight / number-average molecular weight, Mw / Mn) of the above acrylic copolymer has a preferred lower limit of 1.0 and a preferred upper limit of 8.0. When the polydispersity (Mw / Mn) of the above acrylic copolymer is within the above range, the cohesive force of the adhesive layer is further increased, and the bending rigidity of the adhesive tape of this embodiment is further improved. A more preferred lower limit for the polydispersity (Mw / Mn) of the above acrylic copolymer is 1.5, a more preferred upper limit is 7.5, an even more preferred lower limit is 2.0, and an even more preferred upper limit is 7.0. Examples of polydispersity (Mw / Mn) of the above acrylic copolymer include 1.0 to 8.0, 1.5 to 7.5, 2.0 to 7.0, etc.

[0056] The weight-average molecular weight and number-average molecular weight of the above-mentioned acrylic copolymer can be measured by the following method. Specifically, the acrylic copolymer is diluted 50 times with an organic solvent such as ethyl acetate, and the resulting diluted solution is filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm) to prepare a measurement sample. Next, this measurement sample is supplied to a gel permeation chromatograph, and GPC measurement is performed under conditions of sample flow rate of 1 mL / min and column temperature of 40°C. The polystyrene-equivalent molecular weight of the acrylic copolymer is measured, and the obtained values ​​are taken as the weight-average molecular weight and number-average molecular weight. Examples of gel permeation chromatographs include the 2690 Separations Module (manufactured by Waters), and examples of columns include the GPC KF-806L (manufactured by Showa Denko).

[0057] Methods for adjusting the weight-average molecular weight of the above-mentioned acrylic copolymer include, for example, changing the type and amount of polymerization initiator and monomer concentration during the polymerization reaction, adding a small amount of chain transfer agent such as dodecyl mercaptan, controlling chain transfer to the solvent by changing the type of polymerization reaction solvent, and changing the temperature and time during polymerization.

[0058] The preferred lower limit for the content of the acrylic copolymer in the adhesive layer is 25% by mass, and the preferred upper limit is 100% by mass. By having the content of the acrylic copolymer within the above range, the bending rigidity and adhesive strength of the adhesive tape of this embodiment are further improved. A more preferred lower limit for the content of the acrylic copolymer is 50% by mass, a more preferred upper limit is 90% by mass, an even more preferred lower limit is 65% by mass, and an even more preferred upper limit is 85% by mass. Examples of the content of the acrylic copolymer in the adhesive layer include 25% by mass or more and 100% by mass or less, 50% by mass or more and 90% by mass or less, 65% by mass or more and 85% by mass or less, etc.

[0059] As polymerization methods for synthesizing the above-mentioned acrylic copolymer, conventionally known methods can be used in which a mixture of constituent monomers that serve as raw materials undergoes a radical reaction in the presence of a polymerization initiator. Examples include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, and bulk polymerization. Among these, solution polymerization is preferred because it is easy to synthesize.

[0060] When solution polymerization is used as the polymerization method described above, examples of reaction solvents include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, and diethyl ether. These reaction solvents may be used individually or in combination of two or more.

[0061] Examples of polymerization initiators include organic peroxides and azo compounds. Examples of organic peroxides include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-butylperoxylaurate. Examples of azo compounds include azobisisobutyronitrile and azobiscyclohexanecarbonilonitrile. These polymerization initiators may be used alone or in combination of two or more.

[0062] Furthermore, even when the acrylic copolymer is the block copolymer (A), the method for producing the block copolymer (A) is not particularly limited, and conventionally known methods can be used. Specifically, for example, a vinyl aromatic compound may be added to the soft block synthesized in the same manner as the acrylic copolymer described above, and copolymerization may be carried out. Alternatively, the pre-synthesized blocks (A-1) and (A-2) may be copolymerized.

[0063] Furthermore, if the block copolymer is a triblock copolymer having the structure of block (A-1) - block (A-2) - block (A-1), the block copolymer can be obtained, for example, by living polymerization. Examples of living polymerization include living anionic polymerization and RAFT polymerization, but RAFT polymerization is particularly preferred. When producing a block copolymer (A) having the structure of block (A-1) - block (A-2) - block (A-1) by RAFT polymerization, block (A-1) is obtained using a chain transfer agent (RAFT agent), and then the constituent unit monomer of block (A-2) is polymerized or copolymerized in the presence of the obtained block (A-1) to produce a triblock copolymer.

[0064] The preferred lower limit for the content of the constituent unit (b) in the elastomer (E1) is 50% by mass. When the content of the constituent unit (b) is 50% by mass or more, the polarity of the adhesive layer is further reduced, and chemical components become less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. The more preferred lower limit for the content of the constituent unit (b) in the elastomer (E1) is 60% by mass, and the even more preferred lower limit is 75% by mass. Furthermore, the preferred upper limit for the content of the constituent unit (b) in the elastomer (E1) is 95% by mass. When the content of the constituent unit (b) is 95% by mass or less, the adhesive tape of this embodiment has better bending rigidity. The more preferred upper limit for the content of the constituent unit (b) is 92% by mass, and the even more preferred upper limit is 90% by mass. Examples of the content ratio of the above-mentioned constituent unit (b) in the above-mentioned elastomer (E1) include 50% by mass or more and 95% by mass or less, 60% by mass or more and 92% by mass or less, 75% by mass or more and 90% by mass or less, etc.

[0065] In the above constituent unit (b), the SP value is 9.45 (cal / cm³). ３ ) １／２ The SP value of the following compounds is 9.45 (cal / cm³). ３ ) １／２The following may be sufficient, but a preferable upper limit is 9.30 (cal / cm ３ ). １／２ In the above structural unit (b), when the SP value of the compound is 9.45 (cal / cm ３ ), １／２ when the SP value of the compound is 9.30 (cal / cm ３ ), １／２ the polarity of the adhesive layer is further reduced, and it becomes more difficult for the drug component to penetrate into the adhesive layer. As a result, the adhesive tape of the present embodiment can exhibit excellent adhesive performance even when exposed to drugs. In the above structural unit (b), a more preferable upper limit of the SP value of the compound having an SP value of 9.45 (cal / cm ３ ) １／２ is 9.20 (cal / cm ３ ), １／２ a further preferable upper limit is 8.50 (cal / cm ３ ), １／２ and a still more preferable upper limit is 8.40 (cal / cm ３ ). １／２ Among them, from the viewpoint that the adhesive tape of the present embodiment can exhibit even more excellent adhesive performance even when exposed to drugs, the above structural unit (b) preferably contains a structural unit (b') derived from a compound having an SP value of 9.20 (cal / cm ３ ). １／２ In addition, there is no particular lower limit for the SP value of the compound in the above structural unit (b) having an SP value of 9.45 (cal / cm ３ ), １／２ but about 7.90 (cal / cm ３ ) １／２ is a substantial lower limit. In the above structural unit (b), examples of the SP value of the compound having an SP value of 9.45 (cal / cm ３ ) １／２ include, for example, 7.90 (cal / cm ３ ) １／２ or more and 9.30 (cal / cm ３ ) １／２ or less, 7.90 (cal / cm ３ ) １／２ or more and 9.20 (cal / cm ３ ) １／２Below, 7.90 (cal / cm ３ ) １／２ More than 8.50 (cal / cm ３ ) １／２ Below, 7.90 (cal / cm ３ ) １／２ 8.40 (cal / cm) ３ ) １／２ The following are some examples.

[0066] The preferred lower limit for the content of the constituent unit (b') in the elastomer (E1) is 50% by mass. When the content of the constituent unit (b') is 50% by mass or more, the polarity of the adhesive layer is further reduced, and chemical components become less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. The more preferred lower limit for the content of the constituent unit (b') in the elastomer (E1) is 60% by mass, and the even more preferred lower limit is 75% by mass. Furthermore, the preferred upper limit for the content of the constituent unit (b') in the elastomer (E1) is 95% by mass. When the content of the constituent unit (b') is 95% by mass or less, it has excellent bending rigidity. The more preferred upper limit for the content of the constituent unit (b') is 92% by mass, and the even more preferred upper limit is 90% by mass. Examples of the content ratio of the above-mentioned constituent unit (b') in the elastomer (E1) include 50% by mass or more and 95% by mass or less, 60% by mass or more and 92% by mass or less, 75% by mass or more and 90% by mass or less, etc.

[0067] The elastomer (E1) preferably contains at least one elastomer selected from styrene-based elastomers, olefin-based elastomers, and urethane-based elastomers. By containing at least one elastomer selected from styrene-based elastomers, olefin-based elastomers, and urethane-based elastomers in the elastomer (E1), the adhesive layer can better prevent the penetration of chemical components. Among these, styrene-based elastomers are preferred because they have excellent compatibility with the acrylic copolymer and have a low glass transition temperature, which tends to result in the adhesive tape of this embodiment having excellent adhesive strength.

[0068] Preferably, the above styrene-based elastomer includes an aromatic block copolymer (X) having at least two blocks having structural units derived from vinyl aromatic compounds (hereinafter sometimes simply referred to as "vinyl aromatic polymer blocks"), and at least one of a block having structural units derived from a conjugated diene compound (hereinafter sometimes simply referred to as "conjugated diene polymer blocks") and a hydrogenated product of a block having structural units derived from a conjugated diene compound (hereinafter sometimes simply referred to as "hydrogenated product of conjugated diene polymer blocks"). In the aromatic block copolymer (X), the vinyl aromatic polymer blocks act as hard segment portions, and the conjugated diene polymer blocks and the hydrogenated product of the conjugated diene polymer blocks act as soft segment portions, imparting rubber elasticity to the adhesive layer. As a result, the polarity of the adhesive tape of this embodiment is reduced, and the penetration of chemicals is prevented, thereby further improving the adhesive performance after chemical immersion.

[0069] The vinyl aromatic polymer block described above may be any block having 5% by mass or more of constituent units derived from a vinyl aromatic compound, and may also contain constituent units derived from other compounds such as ethylene and 1,3-butadiene (which is converted to an ethylene-butylene structure by hydrogenation). Examples of the vinyl aromatic compound in the vinyl aromatic polymer block include alkylstyrene, halogenated styrene, halogen-substituted alkylstyrene, alkoxystyrene, carboxyalkylstyrene, alkyl ether styrene, alkylsilyl styrene, vinyl benzyl dimethoxy phosphide, vinyl naphthalene, vinyl anthracene, N,N-diethyl-p-aminoethylstyrene, and vinylpyridine.

[0070] Examples of alkylstyrenes include styrene, methylstyrene, dimethylstyrene, and t-butylstyrene. Examples of halogenated styrenes include chlorostyrene, bromostyrene, and fluorostyrene. Examples of halogen-substituted alkylstyrenes include chloromethylstyrene. Examples of alkoxystyrenes include methoxystyrene and ethoxystyrene. Examples of carboxyalkylstyrenes include carboxymethylstyrene. Examples of alkyl ether styrenes include vinyl benzyl propyl ether. Examples of alkylsilyl styrenes include trimethylsilyl styrene. Among these, styrene, methylstyrene, and dimethylstyrene are preferred, and styrene is more preferred because it is readily available industrially. These vinyl aromatic compounds may be used individually or in combination of two or more.

[0071] The preferred lower limit for the content of constituent units derived from the vinyl aromatic compound in the vinyl aromatic polymer block is 7% by mass. A content of 7% or more of constituent units derived from the vinyl aromatic compound further improves the bending rigidity of the adhesive tape of this embodiment. A more preferred lower limit for constituent units derived from the vinyl aromatic compound is 10% by mass. Furthermore, from the viewpoint of further improving the flexibility of the adhesive layer and resulting in an adhesive tape with superior shock absorption, the preferred upper limit for constituent units derived from the vinyl aromatic compound is 35% by mass, and a more preferred upper limit is 30% by mass. Examples of the content of constituent units derived from the vinyl aromatic compound in the vinyl aromatic polymer block include 7% to 35% by mass, 10% to 30% by mass, and so on.

[0072] Examples of the above-mentioned conjugated diene compounds include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-octadiene, 1,3-hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, myrcene, and chloroprene. In addition to the above-mentioned conjugated diene compounds, other usable compounds include, for example, 2,5-dihydrofuran-2,5-dione. Among these, 1,3-butadiene and isoprene are preferred due to their high polymerization reactivity and ease of industrial availability. These conjugated diene compounds may be used individually or in combination of two or more.

[0073] The hydrogenated form of the above-mentioned conjugated diene polymer block refers to a block in which the carbon-carbon double bonds (unsaturated bonds) in the constituent units derived from the above-mentioned conjugated diene compound are converted to saturated bonds by hydrogenation. From the viewpoint of preventing degradation due to heat, ultraviolet rays, etc., it is preferable that 80% or more of the carbon-carbon double bonds (unsaturated bonds) in the constituent units derived from the above-mentioned conjugated diene compound of the aromatic block copolymer (X) are converted to saturated bonds by hydrogenation, more preferably 90% or more, even more preferably 95% or more, and even more preferably 96% or more. Furthermore, it is most preferable that 100% of the unsaturated bonds are converted to saturated bonds by hydrogenation (i.e., it is a completely hydrogenated form).

[0074] The preferred lower limit for the content of constituent units derived from the conjugated diene compound in the above-mentioned conjugated diene polymer block is 80% by mass. A content of 80% by mass or more of constituent units derived from the conjugated diene compound further improves the flexibility of the adhesive layer and the shock absorption of the resulting adhesive tape. Furthermore, the adhesive strength of the adhesive layer is also improved. A more preferred lower limit for the constituent units derived from the conjugated diene compound is 90% by mass, and an even more preferred lower limit is 95% by mass. There is no particular upper limit for the constituent units derived from the conjugated diene compound; it may be 100% by mass.

[0075] Examples of the structure of the above aromatic block copolymer (X) include, when the vinyl aromatic polymer block is B and the hydrogenated product of the block having constituent units derived from the conjugated diene polymer block and the conjugated diene compound is C, a triblock copolymer represented by formula B-C-B, a diblock copolymer represented by formula B-C, a pentablock copolymer represented by formula C-B-C-B-C, and the like.

[0076] Examples of aromatic block copolymers (X) having the structure represented by the above formula B-C-B include styrene-isoprene-styrene (SIS) block copolymer, styrene-butylene-styrene (SBS) block copolymer, styrene-ethylene-butylene-styrene (SEBS) block copolymer, styrene-ethylene-propylene-styrene (SEPS) block copolymer, styrene-ethylene-ethylene-propylene-styrene (SEEPS) block copolymer, styrene-isobutylene-styrene (SIBS) block copolymer, and ethylene-styrene-butylene block copolymer. Among these, SIS block copolymer and SEBS block copolymer are preferred from the viewpoint of compatibility with the above acrylic copolymer.

[0077] The preferred lower limit for the weight-average molecular weight (Mw) of the aromatic block copolymer (X) is 50,000. A weight-average molecular weight (Mw) of 50,000 or more results in a more shock-absorbing adhesive tape. A more preferred lower limit for the weight-average molecular weight of the aromatic block copolymer (X) is 100,000, and an even more preferred lower limit is 150,000. While there is no particular upper limit for the weight-average molecular weight of the aromatic block copolymer (X), a preferred upper limit is 500,000 from the viewpoint of compatibility with the acrylic copolymer. Examples of weight-average molecular weight (Mw) for the aromatic block copolymer (X) include 50,000 to 500,000, 100,000 to 500,000, and 150,000 to 500,000.

[0078] The above-mentioned olefin-based elastomer is an elastomer composed of olefin compounds, and is typically composed of a crystalline olefin block and an amorphous olefin block. In the above-mentioned olefin-based elastomer, the crystalline olefin block acts as a hard segment portion, and the amorphous olefin block acts as a soft segment portion, thereby imparting rubber elasticity to the adhesive layer.

[0079] Examples of the crystalline olefins mentioned above include ethylene and propylene.

[0080] Examples of the amorphous olefins mentioned above include isobutylene.

[0081] The above-mentioned urethane-based elastomer is an elastomer composed of a urethane compound obtained by the reaction of a polyol compound and a polyisocyanate compound. In the above-mentioned urethane-based elastomer, the urethane bond sites and urea bond sites act as hard segment portions, and the polyol chains act as soft segment portions, thereby imparting rubber elasticity to the adhesive layer.

[0082] Examples of the polyol compounds mentioned above include polyester polyols (polycondensates of divalent alcohols and divalent basic acids such as adipic acid, azelaic acid, and sepatic acid), polyether polyols (obtained by addition polymerization of ethylene oxide, tetrahydrofuran, etc.), polyacrylate polyols, polycarbonate polyols, polyolefin polyols, polybutadiene polyols or their hydrogenated products, polyisoprene polyols or their hydrogenated products, phenolic polyols, epoxy polyols, caprolactone polyols, and polysulfone polyols. Copolymer polyols such as polyester-polyether polyols can also be cited as polyol compounds.

[0083] Examples of the polyisocyanate compounds mentioned above include diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene-1,5-diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate, transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanate-methyl)cyclohexane, and dicyclohexylmethane diisocyanate. Alternatively, modified forms of the polyisocyanate compounds mentioned above may be used as the polyisocyanate compounds. Examples of modified polyisocyanate compounds include the bilate modified polyisocyanate compounds mentioned above, the isocyanurate modified polyisocyanate compounds mentioned above, adduct compounds obtained by reacting the polyisocyanate compounds mentioned above with glycerin, trimethylolpropane, or polyols obtained by addition polymerization of these with alkylene oxides such as propylene oxide and ethylene oxide, and polymethylene polyphenyl polyisocyanate, also known as polymeric MDI.

[0084] A preferred lower limit for the total content ratio of constituent unit (a) and constituent unit (b) in the adhesive layer is 40% by mass. When the total content ratio of constituent unit (a) and constituent unit (b) in the adhesive layer is 40% by mass or more, the polarity of the adhesive layer is further reduced, and chemical components become less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferred lower limit for the total content ratio of constituent unit (a) and constituent unit (b) in the adhesive layer is 50% by mass, and an even more preferred lower limit is 60% by mass. Furthermore, a preferred upper limit for the total content ratio of constituent unit (a) and constituent unit (b) in the adhesive layer is 99% by mass. When the total content ratio of constituent unit (a) and constituent unit (b) in the adhesive layer is 99% by mass or less, the polarity of the adhesive layer is further reduced, and chemical components become less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferable upper limit for the total content ratio of the constituent unit (a) and the constituent unit (b) in the adhesive layer is 92% by mass, and an even more preferable upper limit is 84% ​​by mass. Examples of the total content ratio of the constituent unit (a) and the constituent unit (b) in the adhesive layer include 40% by mass or more and 99% by mass or less, 50% by mass or more and 92% by mass or less, 60% by mass or more and 84% by mass or less, etc. Furthermore, in this specification, "total content ratio of the constituent unit (a) and the constituent unit (b)" means the content ratio of the constituent unit (a) or the constituent unit (b) alone present in the adhesive layer when only one of the constituent unit (a) or the constituent unit (b) is present in the adhesive layer.

[0085] The preferred lower limit for the proportion of component (a) in the total content of component (a) and component (b) is 25% by mass. By having a proportion of component (a) of 25% by mass or more in the total content of component (a) and component (b), the adhesive tape of this embodiment exhibits superior bending rigidity. A more preferred lower limit for the proportion of component (a) in the total content of component (a) and component (b) is 40% by mass, and an even more preferred lower limit is 50% by mass. Furthermore, a preferred upper limit for the proportion of component (a) in the total content of component (a) and component (b) is 100% by mass. By having a proportion of component (a) of 100% by mass or less in the total content of component (a) and component (b), the adhesive tape of this embodiment can achieve both excellent adhesive performance and bending rigidity. A more preferable upper limit for the proportion of component unit (a) in the total content of component unit (a) and component unit (b) is 90% by mass, and an even more preferable upper limit is 80% by mass. Examples of the proportion of component unit (a) in the total content of component unit (a) and component unit (b) include 25% by mass or more and 100% by mass or less, 40% by mass or more and 90% by mass or less, 50% by mass or more and 80% by mass or less, etc.

[0086] When the above-mentioned constituent unit (a) contains the above-mentioned constituent unit (a'), and the above-mentioned constituent unit (b) contains the above-mentioned constituent unit (b'), the preferred lower limit of the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') in the adhesive layer is 20% by mass. When the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') in the adhesive layer is 20% by mass or more, the polarity of the adhesive layer is further reduced, and chemical components become less likely to penetrate the adhesive layer. As a result, the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferred lower limit of the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') in the adhesive layer is 25% by mass, and an even more preferred lower limit is 30% by mass. Furthermore, a preferred upper limit of the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') in the adhesive layer is 70% by mass. The adhesive layer has superior adhesive performance when the total content ratio of the constituent unit (a') and the constituent unit (b') in the adhesive layer is 70% by mass or less. A more preferable upper limit for the total content ratio of the constituent unit (a') and the constituent unit (b') in the adhesive layer is 60% by mass, and an even more preferable upper limit is 50% by mass. Examples of the total content ratio of the constituent unit (a') and the constituent unit (b') in the adhesive layer include 20% by mass or more and 70% by mass or less, 25% by mass or more and 60% by mass or less, 30% by mass or more and 50% by mass or less, etc. Furthermore, in this specification, "total content ratio of the constituent unit (a') and the constituent unit (b')" means the content ratio of the constituent unit (a') or the constituent unit (b') alone present in the adhesive layer when only one of the constituent unit (a') or the constituent unit (b') is present.

[0087] When the above-mentioned constituent unit (a) contains the above-mentioned constituent unit (a'), and the above-mentioned constituent unit (b) contains the above-mentioned constituent unit (b'), the preferred lower limit of the proportion of the above-mentioned constituent unit (a') in the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') is 10% by mass. By having a proportion of the above-mentioned constituent unit (a') in the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') of 10% by mass or more, the adhesive tape of this embodiment exhibits superior bending rigidity. A more preferred lower limit for the proportion of the above-mentioned constituent unit (a') in the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') is 20% by mass, and an even more preferred lower limit is 30% by mass. Furthermore, a preferred upper limit for the proportion of the above-mentioned constituent unit (a') in the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') is 100% by mass. By having the proportion of the above-mentioned constituent unit (a') in the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') be 100% by mass or less, the adhesive tape of this embodiment achieves both excellent adhesive performance and bending rigidity. A more preferable upper limit for the proportion of the above-mentioned constituent unit (a') in the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') is 80% by mass, and an even more preferable upper limit is 60% by mass. Examples of the proportion of the above-mentioned constituent unit (a') in the total content ratio of the above-mentioned constituent unit (a') and the above-mentioned constituent unit (b') include 10% by mass or more and 100% by mass or less, 20% by mass or more and 80% by mass or less, 30% by mass or more and 60% by mass or less, etc.

[0088] When the adhesive layer contains the acrylic copolymer and the elastomer (E1), the preferred upper limit of the elastomer (E1) content per 100 parts by mass of the acrylic copolymer is 60 parts by mass. By having an elastomer (E1) content within this range, the adhesive performance of the adhesive tape of this embodiment can be maintained while the polarity of the adhesive tape is reduced, thereby further suppressing the penetration of chemicals. A more preferred upper limit for the elastomer (E1) content is 55 parts by mass, and an even more preferred upper limit is 50 parts by mass. Furthermore, the elastomer (E1) content may be greater than 0 parts by mass, but the preferred lower limit is 10 parts by mass. By having an elastomer (E1) content of 10 parts by mass or more, the flexibility of the adhesive layer is further improved, and the resulting adhesive tape has superior shock absorption properties. A more preferred lower limit for the elastomer (E1) content is 15 parts by mass, an even more preferred lower limit is 20 parts by mass, and an even more preferred lower limit is 30 parts by mass. Examples of the elastomer (E1) content include more than 0 parts by mass and 60 parts by mass or less, 10 parts by mass or more and 55 parts by mass or less, 15 parts by mass or more and 50 parts by mass or less, 20 parts by mass or more and 50 parts by mass or less, 30 parts by mass or more and 50 parts by mass or less, etc.

[0089] The adhesive layer preferably contains a tackifying resin. By including a tackifying resin in the adhesive layer, the adhesive strength and bending rigidity of the adhesive tape of this embodiment are further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals.

[0090] Examples of the tackifying resins mentioned above include rosin resins, rosin ester resins, hydrogenated rosin resins, terpene resins, terpene phenol resins, coumarone indene resins, alicyclic saturated hydrocarbon resins, C5 petroleum resins, C9 petroleum resins, and C5-C9 copolymer petroleum resins. Among these, rosin ester resins or terpene phenol resins are preferred from the viewpoint of compatibility with the acrylic copolymer, and among these, rosin ester resins or terpene phenol resins having hydroxyl groups are more preferred from the viewpoint of further improving the adhesive strength and bending rigidity of the adhesive tape of this embodiment. These tackifying resins may be used alone or in combination of two or more types.

[0091] Examples of rosin ester resins having the hydroxyl group mentioned above include Pencel D-135 and Super Ester A-75 (both manufactured by Arakawa Chemical Industries, Ltd.). Examples of terpene phenol resins include YS Polystar G150 and YS Polystar T160 (both manufactured by Yasuhara Chemical Co., Ltd.).

[0092] If the adhesive layer contains the tackifying resin, it is preferable that the tackifying resin contains bio-derived carbon. By including a bio-derived carbon in the tackifying resin, the content of bio-derived carbon in the adhesive layer described later can be increased, and the environmental burden of the adhesive tape of this embodiment can be further reduced. Specific examples of bio-derived carbon-containing tackifying resins include Pine Crystal KE-604, Pine Crystal KR-140 (all rosin-based resins, manufactured by Arakawa Chemical Industries), Pine Crystal KE-100, Pine Crystal KE-359, Super Ester A-75 (all rosin ester-based resins, manufactured by Arakawa Chemical Industries), and Tamanol 803L (terpene phenol-based resin, manufactured by Arakawa Chemical Industries).

[0093] If the adhesive layer contains the tackifying resin, it is preferable that the tackifying resin has a softening point of 70°C or higher and 170°C or lower. By including a tackifying resin with a softening point of 70°C or higher, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. By including a tackifying resin with a softening point of 170°C or lower, the adhesive layer does not become too hard, the adhesive strength of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. It is more preferable that the tackifying resin contains a tackifying resin with a softening point of 100°C or higher and 160°C or lower, even more preferable that it contains a tackifying resin with a softening point of 120°C or higher and 150°C or lower, and even more preferable that it contains a tackifying resin with a softening point of 130°C or higher and 140°C or lower. In this specification, "softening point of tackifying resin" means the softening temperature measured by JIS K2207 (ring-ball method).

[0094] If the adhesive layer contains the tackifying resin, it is preferable that the tackifying resin has a hydroxyl value of 25 mg KOH / g or more. By including a tackifying resin with a hydroxyl value of 25 mg KOH / g or more, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. It is more preferable that the tackifying resin includes a tackifying resin with a hydroxyl value of 30 mg KOH / g or more, and even more preferable that it includes a tackifying resin with a hydroxyl value of 35 mg KOH / g or more. There is no particular upper limit to the hydroxyl value of the tackifying resin, but from the viewpoint of compatibility with the aromatic block copolymer (X), a preferred upper limit is 50 mg KOH / g. Examples of the hydroxyl value of the tackifying resin include 25 mg KOH / g to 50 mg KOH / g, 30 mg KOH / g to 50 mg KOH / g, and 35 mg KOH / g to 50 mg KOH / g. In this specification, the hydroxyl value of the tackifying resin can be measured by JIS K1557 (phthalic anhydride method).

[0095] When the adhesive layer contains the tackifying resin, the preferred upper limit of the tackifying resin content is 50 parts by mass per 100 parts by mass of the acrylic copolymer. By having a tackifying resin content of 50 parts by mass or less, the adhesive strength of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferred upper limit for the tackifying resin content is 40 parts by mass, an even more preferred upper limit is 30 parts by mass, an even more preferred upper limit is 20 parts by mass, and a particularly preferred upper limit is 10 parts by mass. When the adhesive layer contains the tackifying resin, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. From this viewpoint, a preferred lower limit for the tackifying resin content is 0.1 parts by mass, and a more preferred lower limit is 1.0 part by mass. Furthermore, if the adhesive layer contains the tackifying resin, the content of the tackifying resin can be, for example, 0.1 parts by mass or more and 50 parts by mass or less, 1.0 part by mass or more and 40 parts by mass or less, 1.0 part by mass or more and 30 parts by mass or less, 1.0 part by mass or more and 20 parts by mass or less, 1.0 part by mass or more and 10 parts by mass or less, etc. In addition, the adhesive layer does not have to contain the tackifying resin, and from the viewpoint of further improving the shock absorption of the resulting adhesive tape and making it more suitable for fixing electronic equipment components or in-vehicle components, it is preferable that the adhesive layer does not contain the tackifying resin.

[0096] The adhesive layer may be colored. If the adhesive layer is colored, light-shielding properties can be imparted to the adhesive layer, thereby suppressing deterioration of the adherend to the adhesive tape of this embodiment due to light and ultraviolet rays. Therefore, the adhesive tape of this embodiment can be more suitably used for fixing electronic equipment components or automotive components.

[0097] If the adhesive layer is colored, it is preferable that the adhesive layer contains a coloring agent. Examples of the coloring agent include pigments and dyes. Among these, pigments are preferred because they have excellent heat resistance and the resulting adhesive tape can be more suitably used for fixing electronic equipment components or automotive components. Examples of the pigments include carbon black, aniline black, and titanium dioxide. Among these, carbon black is preferred because it is relatively inexpensive and chemically stable. Examples of the dyes include azo dyes, anthraquinone dyes, and phthalocyanine dyes.

[0098] If the adhesive layer contains a coloring agent, the preferred upper limit of the coloring agent content per 100 parts by mass of the acrylic copolymer is 5.0 parts by mass. A coloring agent content of 5.0 parts by mass or less provides sufficient adhesive strength to the adhesive layer. A more preferred upper limit for the coloring agent content is 4.0 parts by mass, an even more preferred upper limit is 3.5 parts by mass, and an even more preferred upper limit is 2.0 parts by mass. If the adhesive layer contains a coloring agent, the preferred lower limit for the coloring agent content is 0.2 parts by mass. A coloring agent content of 0.2 parts by mass or more provides sufficient light-shielding properties to the adhesive layer. A more preferred lower limit for the coloring agent content is 0.5 parts by mass, an even more preferred lower limit is 0.8 parts by mass, and an even more preferred lower limit is 1.0 part by mass. Furthermore, if the adhesive layer contains the coloring agent, the amount of coloring agent can be, for example, 0.2 parts by mass or more and 5.0 parts by mass or less, 0.5 parts by mass or more and 4.0 parts by mass or less, 0.8 parts by mass or more and 3.5 parts by mass or less, 1.0 part by mass or more and 2.0 parts by mass or less, etc. Also, the adhesive layer does not have to contain a coloring agent, and from the viewpoint of further improving the chemical resistance of the adhesive layer, it is preferable that the adhesive layer does not contain a coloring agent.

[0099] Preferably, the adhesive layer has a structure derived from a crosslinking agent. Because the adhesive layer has a structure derived from a crosslinking agent, the cohesive force of the adhesive layer is increased, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A method for providing the adhesive layer with a structure derived from a crosslinking agent is, for example, to apply an adhesive composition containing a crosslinking agent to a release film or the like, and then heat-dry it.

[0100] The above adhesive composition preferably contains a crosslinking agent. The inclusion of a crosslinking agent in the adhesive composition makes it easier to create an adhesive layer with a structure derived from the crosslinking agent. Therefore, the cohesive force of the adhesive layer is increased, further improving the bending rigidity of the adhesive tape of this embodiment, and enabling the adhesive tape of this embodiment to exhibit excellent adhesive performance even when exposed to chemicals. From the viewpoint of storage stability of the adhesive composition, the crosslinking agent may be added to the adhesive composition immediately before forming the adhesive layer.

[0101] Examples of the crosslinking agents include isocyanate-based crosslinking agents, aziridine-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-based crosslinking agents. Among these, isocyanate-based crosslinking agents are preferred from the viewpoint of further improving the cohesive strength of the adhesive layer.

[0102] The preferred lower limit of the crosslinking agent content per 100 parts by mass of the acrylic copolymer is 0.05 parts by mass, and the preferred upper limit is 5.0 parts by mass. By having the crosslinking agent content within the above range, the degree of crosslinking of the adhesive layer is appropriately adjusted, further improving the adhesive strength and bending rigidity of the adhesive tape of this embodiment, and enabling the adhesive tape of this embodiment to exhibit excellent adhesive performance even when exposed to chemicals. A more preferred lower limit for the crosslinking agent content is 0.10 parts by mass, a more preferred upper limit is 3.0 parts by mass, an even more preferred lower limit is 0.15 parts by mass, an even more preferred upper limit is 2.0 parts by mass, an even more preferred upper limit is 1.0 part by mass, and a particularly preferred upper limit is 0.5 parts by mass. Examples of the crosslinking agent content include 0.05 parts by mass or more and 5.0 parts by mass or less, 0.10 parts by mass or more and 3.0 parts by mass or less, 0.15 parts by mass or more and 2.0 parts by mass or less, 0.15 parts by mass or more and 1.0 part by mass or less, 0.15 parts by mass or more and 0.5 parts by mass or less.

[0103] The adhesive layer described above may contain conventionally known additives such as antioxidants, organic fillers, inorganic fillers, surfactants, stabilizers, and softeners, as needed.

[0104] The preferred lower limit for the gel fraction of the adhesive layer is 10% by mass, and the preferred upper limit is 70% by mass. When the gel fraction of the adhesive layer is 10% by mass or more, the cohesive force of the adhesive layer is further increased, so the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. When the gel fraction of the adhesive layer is 70% by mass or less, the flexibility of the adhesive layer is further improved, so the adhesive strength of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferred lower limit for the gel fraction of the adhesive layer is 20% by mass, a more preferred upper limit is 60% by mass, an even more preferred lower limit is 30% by mass, an even more preferred upper limit is 50% by mass, and an even more preferred lower limit is 40% by mass. Examples of gel fractions for the adhesive layer include 10% to 70% by mass, 20% to 60% by mass, 30% to 50% by mass, and 40% to 50% by mass.

[0105] The gel fraction of the adhesive layer described above can be measured by the following method. Specifically, first, a test specimen is prepared by cutting the adhesive tape having the adhesive layer into a planar rectangular shape with a width of 20 mm and a length of 40 mm. The test specimen is immersed in ethyl acetate at 23°C for 24 hours, then removed from the ethyl acetate and dried at 110°C for 1 hour. The mass of the dried test specimen is measured, and the gel fraction is calculated using the following formula (I). Note that the test specimen does not have a release film laminated on it to protect the adhesive layer. Furthermore, if the adhesive tape of this embodiment is a non-support type adhesive tape without a base material, the measurement can be performed using a test specimen obtained by attaching it to a base material and then cutting it, or without using a base material, W in the following formula (I) can be calculated. ０ Calculate by setting to 0. Gel fraction (mass%) = 100 × (W ２ -W ０ ) / (W １ -W ０ ) (I) (W ０ : Mass of the base material, W １ : Mass of the test specimen before immersion, W ２ (Mass of the test specimen after immersion and drying)

[0106] Methods for adjusting the gel fraction of the adhesive layer include, for example, adjusting the type and content ratio of constituent units derived from polar functional group-containing monomers contained in the acrylic copolymer in the adhesive layer, adjusting the type and content of crosslinking agents to be contained in the adhesive layer, and adjusting the irradiance and irradiation time of electron beams or ultraviolet rays used when electron beam irradiation or ultraviolet irradiation is performed to form the adhesive layer.

[0107] The preferred lower limit for the bio-derived carbon content in the adhesive layer is 10%. A bio-derived carbon content of 10% or more in the adhesive layer results in an adhesive tape that is superior in terms of conserving petroleum resources and reducing carbon dioxide emissions, thereby reducing environmental impact. A more preferred lower limit for the bio-derived carbon content in the adhesive layer is 15%, an even more preferred lower limit is 18%, and an even more preferred lower limit is 20%. Furthermore, there is no particular upper limit for the bio-derived carbon content in the adhesive layer, and it may be 100%. Examples of bio-derived carbon content in the adhesive layer include 10% to 100%, 15% to 100%, 18% to 100%, and 20% to 100%.

[0108] While bio-derived carbon contains a certain percentage of the radioactive isotope C-14, petroleum-derived carbon contains almost no C-14. Therefore, the "biologically derived carbon content" as used herein can be calculated by measuring the concentration of C-14 contained in the adhesive layer. Specifically, it can be measured in accordance with ASTM D6866-24, a standard widely used in the bioplastics industry.

[0109] The content of bio-derived carbon in the adhesive layer can be adjusted by changing the composition of the adhesive layer. Specifically, examples include a method of synthesizing the acrylic copolymer using an alkyl (meth)acrylate containing bio-derived carbon or a polar functional group-containing monomer containing bio-derived carbon, or a method of incorporating a tackifying resin containing bio-derived carbon into the adhesive layer.

[0110] The adhesive layer described above preferably has a foamed structure. Having a foamed structure in the adhesive layer results in a more shock-absorbing adhesive tape, making it more suitable for fixing electronic equipment components or automotive components.

[0111] Methods for forming a foamed structure in the adhesive layer include, for example, a method in which foaming particles are incorporated into the adhesive composition forming the adhesive layer, and then applied to a release film or the like and heat-dried to form a foamed structure; a method in which gas is forcibly mixed and dispersed into the adhesive composition forming the adhesive layer to form a foamed structure; and a method in which liquefied gas is mixed into the adhesive composition forming the adhesive layer to form a foamed structure. Among these, the method in which foaming particles are incorporated into the adhesive composition, and then applied to a release film or the like and heat-dried to form a foamed structure is preferred from the viewpoint that the bubbles formed in the adhesive layer are easily dispersed when the adhesive composition is dried at high temperature, resulting in an adhesive tape with better shock absorption properties and being more suitable for fixing electronic equipment components or automotive components. In other words, it is preferable that the adhesive layer has bubbles derived from foaming particles.

[0112] Examples of the foaming particles mentioned above include those that foam when heated, and may also be thermally expanded particles. Specifically, examples include thermally decomposed foaming agents and thermally expandable microcapsules, and among these, it is preferable that the foaming particles include thermally expandable microcapsules.

[0113] The above-mentioned thermally expandable microcapsules are particles in which a volatile substance such as a low-boiling point solvent is encapsulated inside an outer resin shell. When heated, the outer resin shell softens, and the encapsulated volatile substance volatilizes or expands. As a result, the outer shell expands due to the resulting pressure, increasing the particle size. Therefore, when heated, the thermally expandable microcapsules become hollow particles with air bubbles inside the outer shell. Consequently, in the adhesive layer, the inclusion of thermally expandable microcapsules in the foaming particles prevents gas generated from the foaming particles from escaping to the outside of the adhesive layer, making it easier to maintain an appropriate amount of air bubbles within the adhesive layer and thus improving the foaming ratio of the adhesive layer. As a result, the stress relaxation properties of the adhesive layer are further improved, and the resulting adhesive tape has superior shock absorption properties, making it more suitable for fixing electronic equipment components or automotive components.

[0114] The outer shell resin of the above-mentioned heat-expandable microcapsules is preferably a thermoplastic resin. Examples of the above-mentioned thermoplastic resin include one or more resins selected from vinyl polymers and copolymers thereof such as ethylene, styrene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, butadiene, and chloroprene, polyamides such as nylon 6 and nylon 66, and polyesters such as polyethylene terephthalate. Among these, copolymers of acrylonitrile are preferred from the viewpoint that the encapsulated volatile substances do not easily permeate and the average particle size of the foamed particles, described later, can be adjusted to a suitable range.

[0115] Examples of volatile substances encapsulated inside the above-mentioned thermally expandable microcapsules include hydrocarbons with 3 to 7 carbon atoms such as propane, propylene, butene, n-butane, isobutane, isopentane, neopentane, n-pentane, hexane, and heptane; petroleum ethers; methane halogens such as methyl chloride and methylene chloride; and CCl ３ F, CCl ２ F ２ Examples include one or more low-boiling point liquids selected from chlorofluorocarbons, tetramethylsilanes, trimethylethylsilanes, and other tetraalkylsilanes. Among these, hydrocarbons having 3 to 7 carbon atoms are preferred.

[0116] The preferred upper limit for the average particle size of the foamed particles is 60 μm. When the average particle size of the foamed particles is 60 μm or less, the stress relaxation properties of the adhesive layer are further improved, the shock absorption properties of the adhesive tape of this embodiment are further improved, and it becomes more suitable for use in fixing electronic equipment components or automotive components. A more preferred upper limit for the average particle size of the foamed particles is 55 μm, and an even more preferred upper limit is 50 μm. A preferred lower limit for the average particle size of the foamed particles is 15 μm. When the average particle size of the foamed particles is 15 μm or more, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. A more preferred lower limit for the average particle size of the foamed particles is 20 μm, and an even more preferred lower limit is 25 μm. Examples of the average particle size of the foamed particles include 15 μm to 60 μm, 20 μm to 55 μm, 25 μm to 50 μm, etc. Furthermore, in this specification, the "average particle size of the foaming particles" refers to the average particle diameter of the foaming particles in an unfoamed state, obtained by observing the adhesive composition containing the foaming particles. The average particle size of the foaming particles can also be obtained by randomly selecting particles using an optical microscope or the like and calculating the average of 10 points.

[0117] Furthermore, the expansion initiation temperature of the foaming particles (also called the "foaming initiation temperature") is not particularly limited, but examples include a temperature range of 95°C to 150°C. The "expansion initiation temperature of foaming particles" refers to the temperature at which the foaming particles begin to expand, and can be measured using a thermomechanical analyzer (TMA) or the like.

[0118] Examples of commercially available foaming particles include Expancel 920DU40 (manufactured by Nippon Philite Co., Ltd., average particle size 40 μm), Expancel 920DU80 (manufactured by Nippon Philite Co., Ltd., average particle size 80 μm), EMC-20(B)R (manufactured by Nippon Philite Co., Ltd., average particle size 20 μm), and Advancel EML101 (manufactured by Sekisui Chemical Co., Ltd., average particle size 50 μm).

[0119] If the adhesive layer has a foamed structure, it may have an open-cell structure or a closed-cell structure, but it is preferable to have a closed-cell structure. By having a closed-cell structure in the adhesive layer, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. In addition, since the fracture strength of the adhesive layer is increased, cohesive failure of the adhesive layer can be further suppressed, and the adhesive strength of the adhesive tape of this embodiment is further improved. The cell structure can be confirmed, for example, by observing it at a magnification of 150 to 200 times using an optical microscope (for example, Keyence's "VHX-6000").

[0120] If the adhesive layer has a foamed structure, the deemed density of the adhesive layer has a preferred lower limit of 0.59 g / cm³. ３ Therefore, a preferred upper limit is 1.15 g / cm³. ３ Therefore, by having the deemed density of the adhesive layer within the above range, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. The resulting adhesive tape maintains excellent shock absorption while easily providing better deformation resistance (especially bending resistance). A more preferable lower limit for the deemed density of the adhesive layer is 0.65 g / cm³. ３ A more preferable upper limit is 1.12 g / cm³. ３ A more preferable lower limit is 0.70 g / cm³. ３ A more preferable upper limit is 1.10 g / cm³. ３ A more preferable lower limit is 0.75 g / cm³. ３ A more preferable upper limit is 1.05 g / cm³. ３ A particularly preferred lower limit is 0.80 g / cm³. ３ A particularly preferred upper limit is 1.00 g / cm³. ３ A very preferable upper limit is 0.90 g / cm³. ３ The deemed density of the adhesive layer is, for example, 0.59 g / cm³. ３ 1.15g / cm or more ３ Below, 0.65g / cm ３ 1.12g / cm or more ３Below, 0.70g / cm ３ 1.10g / cm or more ３ Below, 0.75g / cm ３ 1.05g / cm or more ３ , 0.80 g / cm ３ 1.00g / cm or more ３ , 0.80 g / cm ３ 0.90g / cm or more ３ The following are some examples.

[0121] The deemed density of the adhesive layer described above can be measured using an electronic hydrometer (for example, Mirage's "ED120T") in accordance with JIS K7222 or similar standards.

[0122] Methods for adjusting the deemed density of the adhesive layer include, for example, adjusting the type and content of foaming agents such as foaming particles, and changing the composition of the adhesive layer.

[0123] When the adhesive layer has a foamed structure, the average major diameter of the bubbles in the adhesive layer is preferably 10 μm at the lower limit and preferably 80 μm at the upper limit. Having an average major diameter of 10 μm or more of bubbles in the adhesive layer improves the stress relaxation properties of the adhesive layer, further improving the shock absorption properties of the adhesive tape of this embodiment, making it more suitable for fixing electronic equipment components or automotive components. Having an average major diameter of 80 μm or less of bubbles in the adhesive layer improves the bending rigidity of the adhesive tape of this embodiment, allowing it to exhibit excellent adhesive performance even when exposed to chemicals. Furthermore, increasing the tensile strength of the adhesive layer further suppresses cohesive failure of the adhesive layer, thus improving the adhesive strength of the adhesive tape of this embodiment. The more preferable lower limit for the average major diameter of the bubbles in the adhesive layer is 15 μm, the more preferable upper limit is 70 μm, the even more preferable lower limit is 20 μm, the even more preferable upper limit is 65 μm, the even more preferable upper limit is 60 μm, the particularly preferable upper limit is 55 μm, and the very preferable upper limit is 50 μm. Examples of the average major diameter of the bubbles in the adhesive layer include 10 μm to 80 μm, 15 μm to 70 μm, 20 μm to 65 μm, 20 μm to 60 μm, 20 μm to 55 μm, 20 μm to 50 μm, and so on.

[0124] The average minor diameter of the bubbles in the adhesive layer is preferably 10 μm at the lower limit and preferably 75 μm at the upper limit. When the average minor diameter of the bubbles in the adhesive layer is 10 μm or more, the adhesive layer has appropriate flexibility, and the stress relaxation properties of the adhesive layer are further improved, resulting in an adhesive tape with better shock absorption. When the average minor diameter of the bubbles in the adhesive layer is 75 μm or less, the bending rigidity of the adhesive layer is further improved, and the adhesive tape obtained has better bending resistance. In addition, since the fracture strength of the adhesive layer is increased, cohesive failure of the adhesive layer can be further suppressed, resulting in improved adhesive strength and thus improved step-following ability of the adhesive tape of this embodiment. The more preferable lower limit for the average short diameter of the bubbles in the adhesive layer is 15 μm, the more preferable upper limit is 70 μm, the even more preferable lower limit is 20 μm, the even more preferable upper limit is 65 μm, the even more preferable upper limit is 60 μm, the particularly preferable upper limit is 55 μm, and the very preferable upper limit is 50 μm. Examples of the average short diameter of the bubbles in the adhesive layer include 10 μm to 75 μm, 15 μm to 70 μm, 20 μm to 65 μm, 20 μm to 60 μm, 20 μm to 55 μm, 20 μm to 50 μm, etc.

[0125] The aspect ratio of the air bubbles in the adhesive layer described above has a preferred lower limit of 1.00 and a preferred upper limit of 3.50. When the aspect ratio of the air bubbles in the adhesive layer is 1.00 or higher, the structure of the air bubbles in the adhesive layer becomes flattened, and the adhesive layer has appropriate flexibility. As a result, the stress relaxation properties of the adhesive layer are further improved, and the resulting adhesive tape has better shock absorption properties. When the aspect ratio of the air bubbles in the adhesive layer is 3.50 or lower, the bending rigidity of the adhesive layer is further improved, and the resulting adhesive tape has better bending resistance. In addition, since the fracture strength of the adhesive layer is increased, cohesive failure of the adhesive layer can be further suppressed, and as a result the adhesive strength of the adhesive layer is further improved, the step-following ability of the adhesive tape of this embodiment is further improved. A more preferred lower limit for the aspect ratio of the air bubbles in the adhesive layer is 1.25, a more preferred upper limit is 3.00, an even more preferred lower limit is 1.50, and an even more preferred upper limit is 2.50. Examples of aspect ratios for bubbles in the adhesive layer include 1.00 to 3.50, 1.25 to 3.00, 1.50 to 2.50, etc. In this specification, "aspect ratio of bubbles" means the value obtained by dividing the average major diameter of the bubbles by the average minor diameter of the bubbles (average major diameter of bubbles / average minor diameter of bubbles).

[0126] The average major diameter, average minor diameter, and aspect ratio of the bubbles in the adhesive layer can be determined, for example, as follows: Using a razor (Feather Corporation), the adhesive layer is sliced ​​with a plane parallel to the MD (Machine Direction) direction and the thickness direction to obtain an MD cut sample. The obtained MD cut sample is photographed using a digital microscope (for example, Keyence Corporation's "VHX-6000") under conditions such as a magnification of 200x and a measurement screen size of 1.8 mm × 1.3 mm. In the obtained photographed image, the bubble with the largest major diameter and the bubble with the second largest major diameter are selected, and the major and minor diameters of these bubbles are measured to calculate the aspect ratio. Perform this operation for three captured images. The average of the major axes of the six bubbles is taken as the average major axis of the bubbles in the adhesive layer, the average of the minor axes of the six bubbles is taken as the average minor axis of the bubbles in the adhesive layer, and the average of the aspect ratios of the six bubbles is taken as the aspect ratio of the bubbles in the adhesive layer. If the above MD direction is unknown, slice the adhesive layer with a plane parallel to the thickness direction to obtain a cut sample. Slice the sample so that the cutting direction is shifted by 30° from the direction from which the previous cut sample was cut, and measure the aspect ratio in the same manner as above. Repeat the above measurement until returning to the cutting direction of the first measurement. The average of the major axes of the twelve bubbles measured is taken as the average major axis of the bubbles in the adhesive layer, the average of the minor axes of the twelve bubbles is taken as the average minor axis of the bubbles in the adhesive layer, and the average of the aspect ratios of the twelve bubbles is taken as the aspect ratio of the bubbles in the adhesive layer.

[0127] Methods for adjusting the average major diameter of the bubbles in the adhesive layer include, for example, a method of forming the adhesive layer by mechanically stretching and compressing it, a method of including a surfactant or stabilizer in the adhesive composition that forms the adhesive layer, and a method of selecting foaming particles with different particle sizes.

[0128] The thickness of the adhesive layer described above has a preferred lower limit of 50 μm and a preferred upper limit of 500 μm. When the thickness of the adhesive layer is 50 μm or more, the adhesive strength of the adhesive layer is further improved. When the thickness of the adhesive layer is 500 μm or less, the adhesive layer has appropriate flexibility, so the stress relaxation properties of the adhesive layer are further improved, and the adhesive layer has better shock absorption properties. In addition, the step-following ability of the adhesive tape of this embodiment is further improved. A more preferred lower limit for the thickness of the adhesive layer is 80 μm, a more preferred upper limit is 400 μm, an even more preferred lower limit is 100 μm, an even more preferred upper limit is 300 μm, an even more preferred upper limit is 250 μm, and a particularly preferred upper limit is 200 μm. Examples of the thickness of the adhesive layer include 50 μm to 500 μm, 80 μm to 400 μm, 100 μm to 300 μm, 100 μm to 250 μm, 100 μm to 200 μm, and so on.

[0129] In this specification, thickness can be measured using a dial thickness gauge (for example, Mitutoyo's "ABS Digimatic Indicator").

[0130] If the adhesive layer has a foamed structure, it is preferable that the average major diameter of the bubbles in the adhesive layer is 0.80 times or less the thickness of the adhesive layer. By having an average major diameter of bubbles of 0.80 times or less the thickness of the adhesive layer, the bending rigidity of the adhesive tape of this embodiment is further improved, and the adhesive tape of this embodiment can exhibit excellent adhesive performance even when exposed to chemicals. In addition, since the fracture strength of the adhesive layer is increased, cohesive failure of the adhesive layer can be further suppressed, and the adhesive strength of the adhesive tape of this embodiment is further improved. It is more preferable that the average major diameter of the bubbles is 0.70 times or less the thickness of the adhesive layer, even more preferable that it is 0.60 times or less, and even more preferable that it is 0.30 times or less. It is also preferable that the average major diameter of the bubbles is 0.05 times or more the thickness of the adhesive layer. When the average major diameter of the bubbles is 0.05 times or more the thickness of the adhesive layer, the stress relaxation properties of the adhesive layer are further improved, the shock absorption properties of the adhesive tape of this embodiment are further improved, and it becomes more suitable for use in fixing electronic equipment components or automotive components. It is more preferable that the average major diameter of the bubbles is 0.10 times or more the thickness of the adhesive layer. That is, it is preferable that the average major diameter of the bubbles is 0.05 times or more and 0.80 times or less the thickness of the adhesive layer, more preferably 0.10 times or more and 0.70 times or less, even more preferably 0.10 times or more and 0.60 times or less, and even more preferably 0.1 times or more and 0.30 times or less the thickness of the adhesive layer.

[0131] If the adhesive layer has a foamed structure, it is preferable that the adhesive layer has a structure in which no air bubbles are exposed on the surface in the thickness direction. Because the adhesive layer does not have air bubbles exposed on the surface in the thickness direction, the area of ​​the adhesive interface between the adhesive layer and the adherend is increased, and the adhesive strength of the adhesive tape of this embodiment is further improved.

[0132] One method for creating a structure in which no air bubbles are exposed on the surface in the thickness direction of the adhesive layer is to use an adhesive composition containing large foaming particles, thereby suppressing the floating of foaming particles to the liquid surface during the solution coating of the adhesive composition in the adhesive layer formation process.

[0133] The adhesive tape of this embodiment may have layers other than the adhesive layer described above.

[0134] The adhesive tape of this embodiment may or may not have a base material. If the adhesive tape of this embodiment has a base material, the resulting adhesive tape can be given better reworkability. If the adhesive tape of this embodiment does not have a base material, the resulting adhesive tape will be thinner, making it more suitable for fixing electronic equipment components or automotive components. In particular, if the adhesive tape of this embodiment does not have a base material, it is preferable that the adhesive tape of this embodiment consists only of the adhesive layer described above.

[0135] If the adhesive tape of this embodiment has a base material, it may be a single-sided adhesive tape having the adhesive layer on one side of the base material, or it may be a double-sided adhesive tape having adhesive layers on both sides of the base material.

[0136] If the adhesive tape of this embodiment has a base material, the base material is preferably made of a bio-derived material, from the viewpoint of increasing the bio-derived carbon content of the adhesive tape as a whole. Examples of the bio-derived material include polyesters (PES) such as polyethylene terephthalate (PET), polyethylene furanoate (PEF), polylactic acid (PLA), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polybutylene succinate (PBS), as well as polyethylene (PE), polypropylene (PP), polyurethane (PU), triacetylcellulose (TAC), cellulose, and polyamide (PA), all of which are derived from plants.

[0137] Furthermore, from the perspective of reducing environmental impact by decreasing the use of new petroleum resources and suppressing carbon dioxide emissions, base materials made from recycled resources may be used. Methods for recycling resources include, for example, recovering waste from packaging containers, home appliances, automobiles, construction materials, food, etc., or waste generated in the manufacturing process, and using the extracted materials again as raw materials by washing, decontamination, or decomposition by heating or fermentation. Examples of base materials using the above recycled resources include films and nonwoven fabrics made from PET, PBT, PE, PP, PA, etc., using recovered plastics that have been re-resinated as raw materials. Alternatively, the recovered waste may be burned and used as thermal energy for the manufacture of base materials and their raw materials, or the oils and fats contained in the recovered waste may be mixed with petroleum, fractionally distilled, and refined to be used as raw materials.

[0138] When the adhesive tape of this embodiment has a base material, examples of base material types used for the base material include films and nonwoven fabrics. Among these, films are preferred from the viewpoint of the base material having excellent stiffness and further improving the bending rigidity of the adhesive tape of this embodiment, and films containing PES or films containing PA are preferred. Examples of PA include nylon 11, nylon 1010, nylon 610, nylon 510, nylon 410, etc., which are made from castor oil, and nylon 56, etc., which are made from cellulose.

[0139] The preferred lower limit for the thickness of the above-mentioned substrate is 3.5 μm, and the preferred upper limit is 1000 μm. When the thickness of the above-mentioned substrate is within the above range, the balance between the flexibility and rigidity of the substrate is improved, the bending rigidity of the adhesive tape of this embodiment is further improved, and it is easier to obtain excellent shock absorption. A more preferred lower limit for the thickness of the above-mentioned substrate is 5 μm, a more preferred upper limit is 500 μm, an even more preferred lower limit is 6.5 μm, an even more preferred upper limit is 300 μm, an even more preferred lower limit is 10 μm, an even more preferred upper limit is 200 μm, a particularly preferred lower limit is 30 μm, and a particularly preferred upper limit is 100 μm. Examples of the thickness of the above-mentioned substrate include 3.5 μm to 1000 μm, 5 μm to 500 μm, 6.5 μm to 300 μm, 10 μm to 200 μm, 30 μm to 100 μm, etc.

[0140] In this embodiment, if the adhesive layer has a foamed structure, the adhesive tape may have a foamed adhesive layer and a second adhesive layer without a foamed structure on at least one side of the foamed adhesive layer. Therefore, the adhesive tape of this embodiment may have the second adhesive layer on one side of the foamed adhesive layer, or it may have the second adhesive layer on both sides of the foamed adhesive layer. By having the second adhesive layer on at least one side of the foamed adhesive layer in this embodiment, the interlayer strength of the resulting adhesive tape is further improved, and the adhesive strength of the adhesive tape of this embodiment is further improved.

[0141] The adhesive contained in the second adhesive layer described above is not particularly limited as long as it does not impair the effects of the present invention, and conventionally known adhesives can be used. Specifically, examples include acrylic adhesives, urethane adhesives, rubber adhesives, silicone adhesives, etc. Among these, acrylic adhesives are preferred from the viewpoint of the design range of the adhesive and the wide range of adherend selectivity, and acrylic adhesives containing the above-mentioned acrylic copolymer in the adhesive layer having the foam structure described above are more preferred from the viewpoint of further improving the adhesive strength of the adhesive tape of this embodiment.

[0142] The thickness of the second adhesive layer described above has a preferred lower limit of 5 μm and a preferred upper limit of 100 μm. When the thickness of the second adhesive layer is 5 μm or more, the second adhesive layer is able to exhibit adhesive strength to various materials, thereby improving the handling of the adhesive tape of this embodiment. When the thickness of the second adhesive layer is 100 μm or less, the adhesive tape of this embodiment can exhibit better deformation resistance. A more preferred lower limit for the thickness of the second adhesive layer is 10 μm, a more preferred upper limit is 90 μm, an even more preferred lower limit is 15 μm, and an even more preferred upper limit is 80 μm. Examples of the thickness of the second adhesive layer include 5 μm to 100 μm, 10 μm to 90 μm, 15 μm to 80 μm, etc.

[0143] The method for manufacturing the adhesive tape of this embodiment is not particularly limited, and conventionally known methods can be used. For example, the method for manufacturing an adhesive tape consisting only of the adhesive layer described above is as follows. First, a solvent is added to an acrylic copolymer, tackifying resin, foamed particles, etc., to prepare a solution of the adhesive composition. Next, the prepared adhesive composition solution is applied to the release surface of a release film, and the solvent in the solution is dried and removed to form an adhesive layer having a foamed structure. Then, by placing the release surface of the release film on top of the formed adhesive layer, an adhesive tape can be obtained in which the surface of the adhesive layer is covered with the release film.

[0144] Furthermore, the method for manufacturing an adhesive tape having the above-mentioned substrate and having the adhesive layer on at least one side of the substrate is as follows. That is, in the same manner as the method for manufacturing an adhesive tape consisting only of the above-mentioned adhesive layer, the formed foamed adhesive layer is bonded to the substrate, pressed together using a rubber roller to create a laminated and integrated structure, and then cured in a 40°C environment for 72 hours to obtain an adhesive tape having an adhesive layer on one side of the substrate. Alternatively, the adhesive composition may be directly applied to the substrate, dried to form an adhesive layer, and then the release treatment surface of a release film may be placed on top of the formed adhesive layer. Alternatively, an adhesive tape having adhesive layers on both sides of the substrate can be obtained by placing an arbitrary adhesive layer prepared on the other side of the substrate and then laminating and integrating it.

[0145] Furthermore, the method for manufacturing an adhesive tape having the second adhesive layer on at least one side of the adhesive layer is as follows. Specifically, in the same manner as the method for manufacturing an adhesive tape consisting only of the adhesive layer described above, the adhesive layer having a foamed structure formed and the fabricated second adhesive layer are superimposed, then laminated and integrated by pressing them together using a rubber roller, and then cured for 72 hours in a 40°C environment to produce an adhesive tape having the second adhesive layer on one side of the adhesive layer. In addition, by performing the same operation on the other side of the adhesive layer in the adhesive tape having the second adhesive layer on one side of the fabricated adhesive layer, an adhesive tape having the second adhesive layer on both sides of the adhesive layer can be produced.

[0146] Furthermore, adhesive tapes having the second adhesive layer on at least one side of the adhesive layer can also be manufactured using a multilayer extrusion extruder. Specifically, the adhesive composition forming the adhesive layer and the adhesive composition forming the second adhesive layer are supplied to a multilayer extrusion extruder, and after melt-mixing, a sheet-like adhesive tape base roll in which the adhesive layer and the second adhesive layer are laminated is extruded to produce the tape.

[0147] In this embodiment, when a chemical immersion test is performed on the adhesive tape, which is conducted by laminating the adhesive tape to SUS to create a laminate, and then immersing the laminate in a mixed solution of isopropanol and water in a volume ratio of 7:3 at 65°C and 90% RH for 48 hours, the preferred lower limit of the ratio of the 180° peel strength of the adhesive tape to SUS at 23°C before the chemical immersion test (which may also be simply referred to as the "adhesion retention rate of the adhesive tape before and after the chemical immersion test") is 25%. By having an adhesion retention rate of 25% or more, the adhesive tape of this embodiment is more likely to maintain its adhesive strength even when exposed to chemicals. A more preferable lower limit for the adhesion retention rate of the above adhesive tape before and after the chemical immersion test is 30%, and an even more preferable lower limit is 40%. There is no particular upper limit for the adhesion retention rate of the above adhesive tape before and after the chemical immersion test, but 95% is a practical upper limit. Examples of adhesion retention rates of the above adhesive tape before and after the chemical immersion test include 25% to 95%, 30% to 95%, and 40% to 95%.

[0148] The adhesion retention rate of the above adhesive tape before and after chemical immersion testing is calculated by the following method. Specifically, one adhesive layer of the adhesive tape is backed with a 50 μm thick PET film (Toyobo Co., Ltd., "E5100"), and a test piece with a width of 5 mm and a length of 40 mm is prepared. Next, the prepared test piece is attached to a SUS plate by rolling it back and forth once at a speed of 300 mm / min using a 2 kg rubber roller, and then cured at 23°C for 72 hours to prepare a measurement sample. The measurement sample is then placed in an oven set to 65°C and 90% RH and left to stand for 48 hours, after which the measurement sample is removed and left to stand at 23°C and 50% RH for 24 hours. Then, in accordance with JIS Z0237, a peel test was performed using a tensile testing machine (Shimadzu Corporation, "AG-IS") under the conditions of 23°C, 50% RH, and a peel rate of 300 mm / min. The 180° peel force (N / 5 mm) of the adhesive tape against SUS at 23°C before the chemical immersion test, which was left standing for 48 hours in an environment of 65°C and 90% RH, was measured. Next, a similar measurement sample was prepared, and an immersion test was performed on the prepared sample by immersing it in a mixed solution of isopropanol and water in a volume ratio of 7:3 in an environment of 65°C and 90% RH for 48 hours, after which it was left standing for 24 hours in an environment of 23°C and 50% RH. Then, in accordance with JIS Z0237, a peel test was performed using a tensile testing machine (Shimadzu Corporation, "AG-IS") under the conditions of 23°C, 50% RH, and a peeling speed of 300 mm / min. The 180° peel force (N / 5 mm) of the adhesive tape against SUS at 23°C was measured after a chemical immersion test in an environment of 65°C and 90% RH for 48 hours. Using the measured 180° peel force, the adhesion retention rate of the adhesive tape before and after the chemical immersion test can be calculated using the following formula: Adhesion retention rate of adhesive tape before and after chemical immersion test (%) = {(180° peel force of the adhesive tape against SUS at 23°C after the chemical immersion test) / (180° peel force of the adhesive tape against SUS at 23°C before the chemical immersion test)} × 100

[0149] Methods for adjusting the adhesion retention rate of the above-mentioned adhesive tape before and after chemical immersion testing include, for example, adjusting the type of constituent units of the acrylic copolymer or the elastomer (E1).

[0150] The thickness of the adhesive tape in this embodiment has a preferred lower limit of 60 μm and a preferred upper limit of 300 μm. A thickness of 60 μm or more in this embodiment improves the shock absorption of the resulting adhesive tape. A thickness of 300 μm or less in this embodiment improves the bending rigidity of the adhesive tape, making it more suitable for fixing electronic equipment components or automotive components. A more preferred lower limit for the thickness of the adhesive tape in this embodiment is 80 μm, a more preferred upper limit is 250 μm, an even more preferred lower limit is 100 μm, and an even more preferred upper limit is 200 μm. Examples of the thickness of the adhesive tape in this embodiment include 60 μm to 300 μm, 80 μm to 250 μm, 100 μm to 200 μm, etc. Furthermore, "thickness of adhesive tape" in this specification does not include the thickness of the separator, such as a release film, that protects the outermost adhesive layer of the adhesive tape.

[0151] The adhesive tape of this embodiment has a preferred upper limit of 70% for light transmittance at a wavelength of 550 nm. By having a light transmittance of 70% or less at a wavelength of 550 nm, the adhesive tape of this embodiment can be more suitably used for fixing internal components of electrical and electronic equipment. A more preferred upper limit for the light transmittance of the adhesive tape of this embodiment at a wavelength of 550 nm is 60%, an even more preferred upper limit is 50%, an even more preferred upper limit is 40%, a particularly preferred upper limit is 30%, and a very preferred upper limit is 10%. There is no particular lower limit for the light transmittance of the adhesive tape of this embodiment at a wavelength of 550 nm, with 0% being the most preferred. Examples of the light transmittance of the adhesive tape of this embodiment at a wavelength of 550 nm include 0% to 70%, 0% to 60%, 0% to 50%, 0% to 40%, 0% to 30%, and 0% to 10%. Furthermore, the transmittance of the adhesive tape of this embodiment at a wavelength of 550 nm can be measured using a spectrophotometer (such as the "V-670" manufactured by JASCO Corporation).

[0152] The adhesive tape of this embodiment is not particularly limited in its use, but because it can exhibit excellent adhesive performance even when exposed to chemicals, it can be suitably used for fixing parts in products that are cleaned or disinfected with alcohol-based solvents during the manufacturing process, and is more suitably used for fixing electronic equipment parts or automotive parts. Examples of the electronic equipment include televisions, monitors, and portable electronic devices, and examples of the automotive parts include automotive electronic equipment.

[0153] An electronic device including the adhesive tape of this embodiment is also one of these embodiments. The electronic device of this embodiment is not particularly limited as long as it includes the adhesive tape, but examples include electronic devices in which electronic components are bonded and fixed together with the adhesive tape, and specifically, examples include smartphones and display devices in which a display and a housing are bonded together with the adhesive tape, or a fixed cover panel and a housing having irregularities.

[0154] According to the present invention, it is possible to provide an adhesive tape that can exhibit excellent adhesive performance even when exposed to chemicals. Furthermore, according to the present invention, it is possible to provide an electronic device that includes the adhesive tape.

[0155] This is a schematic diagram illustrating the compression test method.

[0156] The embodiments of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The materials used in the examples and comparative examples are as follows.

[0157] <Preparation of n-heptyl acrylic acid containing bio-derived carbon> Ricinoleic acid derived from castor oil was cracked to obtain a mixture containing undecylenic acid and n-heptyl alcohol. Then, undecylenic acid was separated from the obtained mixture by distillation to obtain n-heptyl alcohol containing bio-derived carbon. By esterifying the obtained n-heptyl alcohol containing bio-derived carbon with acrylic acid (manufactured by Nippon Shokubai Co., Ltd.), n-heptyl acrylic acid containing bio-derived carbon was prepared.

[0158] <Preparation of Isobornyl Methacrylate Containing Biologically Derived Carbon> Pinene extracted from pine resin was isomerized to obtain camphene containing biologically derived carbon. By reacting camphene containing biologically derived carbon with methacrylic acid (manufactured by Mitsubishi Chemical Corporation), isobornyl methacrylate containing biologically derived carbon was prepared.

[0159] <Preparation of Isobornyl Acrylate Containing Biologically Derived Carbon> Pinene extracted from pine resin was isomerized to obtain camphene containing biologically derived carbon. By reacting camphene containing biologically derived carbon with acrylic acid (manufactured by Nippon Shokubai Co., Ltd.), isobornyl acrylate containing biologically derived carbon was prepared.

[0160] <Biologically derived, carbon-free monomers> ・Methyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) ・Methyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) ・n-butyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) ・Ethylene-butylene macromonomer (ethylene-butylene macromonomer with an acryloyl group at one end, manufactured by Kraton Polymers, "HPVM-L1253", number average molecular weight: 7000) ・Acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) ・2-hydroxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) ・4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0161] <Elastomers (E1)> ・Styrene-based elastomer A: SIS block copolymer (manufactured by Zeon Corporation, "Quintac 3620", styrene ratio 14%, diblock ratio 12%) ・Styrene-based elastomer B: SIS block copolymer (manufactured by Zeon Corporation, "Quintac 3280", styrene ratio 25%, diblock ratio 17%) ・Styrene-based elastomer C: SEPS block copolymer (manufactured by Kuraray Co., Ltd., "SEPTON 2063", styrene ratio 13%) ・Styrene-based elastomer D: SEBS block copolymer (manufactured by ENEOS Material Corporation, "DYNARON 8600P", styrene ratio 15%)

[0162] <Expandable Particles> - Thermally expandable microcapsule A: Expancel 920DU40 (manufactured by Nippon Philite Co., Ltd., average particle size 40 μm) - Thermally expandable microcapsule B: EMC-20(B)R (manufactured by Nippon Philite Co., Ltd., average particle size 20 μm)

[0163] <Tackifying Resin> ・Terpene-based resin: YS Resin PX1000 (manufactured by Yasuhara Chemical Co., Ltd.)

[0164] <Coloring agent> ・Carbon black: Multi-rack A903 Black (manufactured by Toyo Color Co., Ltd.)

[0165] <Crosslinking agent> ・Isocyanate-based crosslinking agent: Desmodulo L-75 (manufactured by Covestro)

[0166] (Synthesis of acrylic copolymers A to O) A reactor equipped with a thermometer, stirrer, and condenser was prepared. A mixture of the constituent unit monomers shown in Tables 1 and 2 and 80 parts by mass of ethyl acetate were added to the reactor, and the reactor was heated and reflux was started. Subsequently, 0.01 parts by mass of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added to the reactor as a polymerization initiator, and polymerization was started under reflux. Next, 0.01 parts by mass of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added 1 hour and 2 hours after the start of polymerization, and further, 0.05 parts by mass of t-hexylperoxypivalate was added 4 hours after the start of polymerization to continue the polymerization reaction. Eight hours after the start of polymerization, an ethyl acetate solution of the acrylic copolymer was obtained. The weight-average molecular weight of the obtained acrylic copolymer was measured using a 2690 Separations Module (Waters Co., Ltd.) as the measuring instrument, a GPCKF-806L column (Showa Denko Corporation), and ethyl acetate as the solvent, under conditions of a sample flow rate of 1 mL / min and a column temperature of 40°C. The results are shown in Tables 1 and 2.

[0167]

[0168]

[0169] (Example 1) (1) Preparation of adhesive tape To the solution of acrylic copolymer A obtained in "(Synthesis of acrylic copolymer)" described above, 0.75 parts by mass of isocyanate-based crosslinking agent and 30 parts by mass of ethyl acetate as a solvent were added to 100 parts by mass of the solid content of acrylic copolymer A, and the mixture was thoroughly stirred to prepare a solution containing an adhesive composition. The prepared solution containing the adhesive composition was applied to the release surface of a 50 μm thick release PET film, and then heated at 115°C for 1 hour to dry the solvent and foam the adhesive composition layer, thereby forming an adhesive layer with a thickness of 200 μm. The obtained adhesive layer did not have a foamed structure. The obtained adhesive layer was bonded to the release surface of a 50 μm thick release PET film, and then cured at 40°C for 48 hours to obtain an adhesive tape having only an adhesive layer, and an adhesive tape with a release PET film in which the surface of the adhesive layer is protected by the release PET film.

[0170] (2) Measurement of the bio-derived carbon content of the adhesive layer The release PET films on both sides were peeled off from the obtained adhesive tape, and the bio-derived carbon content of the obtained adhesive layer was measured in accordance with ASTM D6866-24. The results are shown in Table 3.

[0171] (3) Measurement of the gel fraction of the adhesive layer The release PET film was peeled off one side of the obtained adhesive tape and bonded to a 23 μm thick base PET film (Futamura Chemical Co., Ltd., "FE2002"), and cut into a flat rectangular shape with a width of 20 mm and a length of 40 mm. The release PET film was then peeled off the other side of the adhesive tape to prepare a test piece, and its mass was measured. The test piece was immersed in ethyl acetate at 23°C for 24 hours, then removed from the ethyl acetate and dried at 110°C for 1 hour. The mass of the dried test piece was measured, and the gel fraction (mass %) was calculated using the above formula (I). The results are shown in Table 3.

[0172] (4) 180° peel strength of adhesive tape on SUS at 23°C The release PET film on one side (the side not measured) of the obtained adhesive tape was peeled off, and the adhesive layer was pressed onto a 23 μm thick polyethylene terephthalate film by running a 2 kg rubber roller back and forth once at a speed of 300 mm / min. After that, it was cut to a width of 25 mm x length of 75 mm to prepare a test piece. Next, the adhesive layer on the other side of the prepared test piece was attached to a SUS304 plate (a SUS304 plate that had been washed with ethanol and then wiped dry), and pressed by running a 2 kg rubber roller back and forth once at a speed of 300 mm / min. After that, it was cured for 20 minutes in an environment of 23°C and 50% RH to prepare a test sample. The obtained test samples were tested in accordance with JIS Z 0237:2009, by peeling the adhesive layer from the SUS304 plate at 23°C, 50% RH, a tensile speed of 300 mm / min, and a peel angle of 180°. The 180° peel force of the adhesive tape against SUS at 23°C was measured. The results are shown in Table 3.

[0173] (5) Calculation of the slope of the line in the compression test of the adhesive tape First, aluminum alloy plates (SHAANXISHEW-ESTEELPIPE, "Aluminum 6061-T6", thickness 1.6 mm, width 25.4 mm, length 203.2 mm) were attached to both sides of the obtained adhesive tape by applying a load of 1 MPa for 20 seconds at a 65°C environment to laminate and integrate them, and then the laminate was cured by leaving it undisturbed at a 23°C environment for 24 hours to produce laminate 1. Next, the produced laminate 1 was set up in a Tensilon (A&D Company, Limited) used as a measuring instrument in accordance with JIS K7171 as shown in Figure 1 (distance between compression jigs: 57.15 mm, distance between fixing jigs: 177.8 mm), and a compression test was performed on the laminate 1 under the conditions of a temperature of 22 to 24°C, a humidity of 45 to 55%, and a compression speed of 0.05 mm / s, until the load reached 50 N. Then, using the least squares method, the slope of the regression line (stress / deformation) was calculated for all data points in the obtained stress-deformation curve where the stress falls within the interval of 20 N to 50 N, thereby obtaining the slope of the line in the compression test of the adhesive tape described above. The results are shown in Table 3.

[0174] (6) Calculation of the adhesion retention rate of the adhesive tape before and after chemical immersion test One adhesive layer of the obtained adhesive tape was backed with a 50 μm thick PET film (Toyobo Co., Ltd., "E5100"), and a test piece with a width of 5 mm and a length of 40 mm was prepared. Next, the prepared test piece was attached to a SUS plate by rolling it back and forth once at a speed of 300 mm / min using a 2 kg rubber roller, and then cured at 23°C for 72 hours to prepare a measurement sample. The measurement sample was then placed in an oven set to 65°C and 90% RH and left to stand for 48 hours, after which the measurement sample was removed and left to stand in an environment of 23°C and 50% RH for 24 hours. Then, in accordance with JIS Z0237, a peel test was performed using a tensile testing machine (Shimadzu Corporation, "AG-IS") under the conditions of 23°C, 50% RH, and a peel rate of 300 mm / min. The 180° peel force (N / 5 mm) of the adhesive tape against SUS at 23°C was measured before the chemical immersion test, in which the tape was left standing for 48 hours in an environment of 65°C and 90% RH. Next, a similar measurement sample was prepared, and the prepared sample was subjected to an immersion test in a mixed solution of isopropanol and water in a volume ratio of 7:3, in an environment of 65°C and 90% RH for 48 hours, after which it was left standing for 24 hours in an environment of 23°C and 50% RH. Then, in accordance with JIS Z0237, a peel test was conducted using a tensile testing machine (Shimadzu Corporation, "AG-IS") under the conditions of 23°C, 50% RH, and a peel rate of 300 mm / min. After a chemical immersion test in an environment of 65°C and 90% RH for 48 hours, the 180° peel force (N / 5 mm) of the adhesive tape against SUS at 23°C was measured. Using the measured 180° peel force, the adhesion retention rate of the adhesive tape before and after the chemical immersion test was calculated using the following formula. The results are shown in Table 3. Adhesion retention rate of adhesive tape before and after chemical immersion test (%) = {(180° peel force of the adhesive tape against SUS at 23°C after the chemical immersion test) / (180° peel force of the adhesive tape against SUS at 23°C before the chemical immersion test)} × 100

[0175] (Examples 2-11, 14-18, 20-29, Comparative Examples 1-4) Except for the fact that the composition and thickness of the adhesive layer were as shown in Tables 3-5 in "(1) Preparation of adhesive tape" described above, adhesive tape was prepared and various measurements were performed in the same manner as in Example 1. The results are shown in Tables 3-5.

[0176] (Examples 12-13) (1) Preparation of adhesive tape Adhesive tape was prepared in the same manner as in Example 1, except that the composition and thickness of the adhesive layer were as shown in Table 3. The adhesive layer in Examples 12-13 had a foamed structure, and the obtained adhesive layer was cut using a razor (Feather Corporation) and the surface in the thickness direction of the adhesive layer was observed using an optical microscope (for example, Keyence Corporation, "VHX-6000"), and it was found that the obtained adhesive layer had a structure in which no air bubbles were exposed on the surface in the thickness direction.

[0177] (2) Measurement of the bio-derived carbon content of the adhesive layer The bio-derived carbon content was measured using the same method as in Example 1. The results are shown in Table 3.

[0178] (3) Measurement of the gel fraction of the adhesive layer The gel fraction of the adhesive layer was measured using the same method as in Example 1. The results are shown in Table 3.

[0179] (4) Measurement of the deemed density of the adhesive layer The deemed density of the adhesive layer of the obtained adhesive tape is measured in accordance with JIS K7222 (g / cm³) ３ The following was measured. The results are shown in Table 3.

[0180] (5) Calculation of the ratio of the average major diameter of the bubbles to the thickness of the adhesive layer Using a razor (Feather Co., Ltd.), the adhesive layer of the obtained adhesive tape was sliced ​​in a plane parallel to the thickness direction to obtain cut samples. The slice was made so that the cutting direction was shifted by 30° from the direction in which the previous cut sample was made, and the aspect ratio was measured in the same manner as above. The above measurement was repeated until it returned to the cutting direction of the first measurement, and the average of the major diameters of the total of 12 bubbles measured was taken as the average major diameter of the bubbles in the adhesive layer. Then, using the obtained average major diameter of the bubbles in the adhesive layer, the ratio of the average major diameter of the bubbles to the thickness of the adhesive layer was calculated. The results are shown in Table 3.

[0181] (6) 180° peel force of adhesive tape against SUS at 23°C The 180° peel force of the adhesive tape against SUS at 23°C was measured using the same method as in Example 1. The results are shown in Table 3.

[0182] (7) Calculation of the slope of the line in the compression test of the adhesive tape The slope of the line in the compression test of the adhesive tape was calculated using the same method as in Example 1. The results are shown in Table 3.

[0183] (8) Calculation of the adhesion retention rate of the adhesive tape before and after the chemical immersion test The adhesion retention rate of the adhesive tape before and after the chemical immersion test was calculated using the same method as in Example 1. The results are shown in Table 3.

[0184] (Example 19) An adhesive layer was formed in the same manner as in Example 1, except that the composition and thickness of the adhesive layer were as shown in Table 4. The adhesive layer in Example 19 did not have a foamed structure. The obtained adhesive layer was bonded to one side of the substrate shown in Table 4, and then pressed down by running a 2 kg rubber roller back and forth once at a speed of 300 mm / min. Furthermore, an adhesive layer with the same composition and thickness was prepared and bonded to the other side of the substrate, and then pressed down by running a 2 kg rubber roller back and forth once at a speed of 300 mm / min to laminate and integrate it, and then cured for 1 hour in an environment of 23°C to obtain an adhesive tape having adhesive layers on both sides of the substrate. In Table 4, "PET film" refers to Lumirror (thickness: 50 μm) manufactured by Toray Industries, Inc. The various measurements were carried out in the same manner as in Example 1, except that, in "(2) Measurement of the bio-derived carbon content of the adhesive layer" and "(3) Measurement of the gel fraction of the adhesive layer" described above, only the adhesive layer was removed from the obtained adhesive tape using a cutter knife and then measured using the same method as in Example 1. The results are shown in Table 4.

[0185] <Evaluation> The adhesive tapes obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 3 to 5.

[0186] (Adhesive performance when exposed to chemicals) In the above-mentioned "(6) Adhesion retention rate of adhesive tape before and after chemical immersion test", the adhesive performance of the adhesive tape when exposed to chemicals was evaluated using the 180° peel force against SUS at 23°C after the chemical immersion test, according to the following criteria: A: The 180° peel force at 23°C after chemical immersion was 5.0 N / mm or more. B: The 180° peel force at 23°C after chemical immersion was 3.0 N / mm or more and less than 5.0 N / mm. C: The 180° peel force at 23°C after chemical immersion was 2.0 N / mm or more and less than 3.0 N / mm. D: The 180° peel force at 23°C after chemical immersion was less than 2.0 N / mm.

[0187]

[0188]

[0189]

[0190] According to the present invention, it is possible to provide an adhesive tape that can exhibit excellent adhesive performance even when exposed to chemicals. Furthermore, according to the present invention, it is possible to provide an electronic device that includes the adhesive tape.

[0191] 1. Laminate 2. Compression jig 3. Fixing jig

Claims

1. An adhesive tape having at least one adhesive layer, wherein the adhesive layer contains at least one selected from the group consisting of an acrylic copolymer having constituent units derived from a (meth)acrylic compound and an elastomer (E1) other than an acrylic elastomer, the adhesive tape has a 180° peel force of 8 N / 25 mm or more against SUS at 23°C, and the adhesive tape is subjected to a compression test in accordance with JIS K7171, in which a laminate formed by laminating aluminum alloy plates to both sides of the adhesive tape is compressed until the load reaches 50 N at a temperature of 22 to 24°C, a humidity of 45 to 55%, and a compression speed of 0.05 mm / s, and the slope of the regression line (stress / deformation) calculated using the least squares method for all data points in the stress-deformation curve obtained, where the stress is within the interval of 20 N to 50 N, is 15.5 N / mm or more.

2. The acrylic copolymer has an SP value of 9.45 (cal / cm²). ３ ) １／２ The following constituent units (a) derived from a (meth)acrylic compound are present, and the elastomer (E1) has an SP value of 9.45 (cal / cm³). ３ ) １／２ The adhesive tape according to claim 1, which satisfies at least one of the following conditions: having a constituent unit (b) derived from a compound.

3. The adhesive tape according to claim 2, wherein the adhesive layer contains the acrylic copolymer, and the acrylic copolymer has the constituent unit (a).

4. The adhesive tape according to claim 3, wherein the content of the constituent unit (a) in the acrylic copolymer is 30% by mass or more.

5. The aforementioned constituent unit (a) has an SP value of 9.20 (cal / cm³). ３ ) １／２ The adhesive tape according to claim 3 or 4, comprising a constituent unit (a') derived from the following (meth)acrylic compound.

6. The adhesive tape according to claim 5, wherein the content of the constituent unit (a') in the acrylic copolymer is 5% by mass or more.

7. The adhesive tape according to claim 3, 4, 5, or 6, wherein the constituent unit (a) includes a constituent unit derived from an alkyl (meth)acrylate having an alkyl group having 12 or more carbon atoms.

8. The adhesive tape according to claim 3, 4, 5, 6, or 7, wherein the constituent unit (a) includes a constituent unit derived from a macromonomer having a number average molecular weight of 2,000 or more and 30,000 or less.

9. The adhesive tape according to claim 8, wherein the constituent unit (a) includes a constituent unit derived from an olefin polymer having a polymerizable unsaturated double bond at its terminal, and the content ratio of the constituent unit derived from the olefin polymer having a polymerizable unsaturated double bond at its terminal in the acrylic polymer is 5% by mass or more and 30% by mass or less.

10. The adhesive tape according to claim 2, 3, 4, 5, 6, 7, 8, or 9, wherein the adhesive layer contains the elastomer (E1), and the elastomer (E1) has the constituent unit (b).

11. The adhesive tape according to claim 10, wherein the content ratio of the constituent unit (b) in the elastomer (E1) is 50% by mass or more.

12. The aforementioned constituent unit (b) has an SP value of 9.20 (cal / cm³). ３ ) １／２ The adhesive tape according to claim 10 or 11, comprising a constituent unit (b') derived from the following compound.

13. The adhesive tape according to claim 12, wherein the content ratio of the constituent unit (b') in the elastomer (E1) is 50% by mass or more.

14. The adhesive tape according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, wherein the adhesive layer contains the acrylic copolymer and the elastomer (E1), the acrylic copolymer having the constituent unit (a), and the elastomer (E1) having the constituent unit (b).

15. The adhesive tape according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or 14, wherein the total content ratio of the constituent unit (a) and the constituent unit (b) in the adhesive layer is 40% by mass or more.

16. The adhesive tape according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, wherein the proportion of the constituent unit (a) in the total content ratio of the constituent unit (a) and the constituent unit (b) is 25% by mass or more.

17. When at least one of the following conditions is satisfied: the constituent unit (a) contains a constituent unit (a') derived from a (meth)acrylic compound having an SP value of 9.20 (cal / cm ３ ), １／２ and the constituent unit (b) contains a constituent unit (b') derived from a compound having an SP value of 9.20 (cal / cm ３ ), １／２ the adhesive tape according to any one of claims 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16, wherein the total content ratio of the constituent unit (a') and the constituent unit (b') in the adhesive layer is 20% by mass or more.

18. The constituent unit (a) has an SP value of 9.20 (cal / cm³). ３ ) １／２ It contains the following constituent unit (a') derived from a (meth)acrylic compound, and the constituent unit (b) has an SP value of 9.20 (cal / cm³). ３ ) １／２ The adhesive tape according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17, wherein the total content ratio of the constituent unit (a') and the constituent unit (b') in the adhesive layer is 50% by mass or less, in which case the adhesive tape satisfies at least one of the following conditions: it contains a constituent unit (b') derived from a compound, and the total content ratio of the constituent unit (a') and the constituent unit (b') in the adhesive layer is 50% by mass or less.

19. The aforementioned constituent unit (a) has an SP value of 9.20 (cal / cm³). ３ ) １／２ It contains the following constituent unit (a') derived from a (meth)acrylic compound, and the constituent unit (b) has an SP value of 9.20 (cal / cm³). ３ ) １／２ The adhesive tape according to claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18, wherein the adhesive tape satisfies at least one of the following conditions, and the proportion of the constituent unit (a') in the total content ratio of the constituent unit (a') and the constituent unit (b') is 10% by mass or more.

20. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19, wherein the acrylic copolymer has constituent units derived from an alkyl (meth)acrylate having a linear or branched alkyl group with 6 to 8 carbon atoms.

21. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, wherein the constituent units derived from the (meth)acrylic acid ester include a constituent unit having an aliphatic cyclic structure derived from the (meth)acrylic acid ester.

22. The adhesive tape according to claim 21, wherein the acrylic copolymer has constituent units derived from isobornyl methacrylate.

23. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22, wherein the acrylic copolymer has constituent units derived from an alkyl (meth)acrylate, which has a glass transition temperature of 0°C or higher when formed as a homopolymer.

24. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23, wherein the acrylic copolymer has constituent units derived from a polar functional group-containing monomer, and the content of constituent units derived from the polar functional group-containing monomer in the acrylic copolymer is 0.1% by mass or more.

25. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24, wherein the acrylic copolymer has constituent units derived from a vinyl aromatic compound, and the content ratio of constituent units derived from the vinyl aromatic compound in the acrylic copolymer is 2.5% by mass or more and 15% by mass or less.

26. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25, wherein the acrylic copolymer has a weight-average molecular weight of 300,000 or more and 1,500,000 or less.

27. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or 26, wherein the elastomer (E1) comprises at least one elastomer selected from styrene-based elastomers, olefin-based elastomers, and urethane-based elastomers.

28. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, or 27, wherein the adhesive layer contains the acrylic copolymer and the elastomer (E1), and the content of the elastomer (E1) is 60 parts by mass or less per 100 parts by mass of the acrylic copolymer.

29. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28, wherein the adhesive layer does not contain a tackifying resin, or the adhesive layer contains a tackifying resin, and the content of the tackifying resin is 50 parts by mass or less per 100 parts by mass of the acrylic copolymer.

30. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29, wherein the adhesive layer contains a coloring agent.

31. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30, wherein the adhesive layer has a structure derived from a crosslinking agent.

32. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or 31, wherein the adhesive layer has a bio-derived carbon content of 15% or more.

33. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32, wherein the adhesive layer has a gel fraction of 10% by mass or more and 70% by mass or less.

34. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, or 33, wherein the adhesive layer has a foamed structure and the adhesive layer has bubbles derived from foaming particles.

35. The adhesive tape according to claim 34, wherein the foaming particles include thermally expandable microcapsules.

36. The adhesive tape according to claim 34 or 35, wherein the foaming particles have an average particle size of 60 μm or less.

37. The adhesive tape according to claim 34, 35, or 36, wherein the adhesive layer has an average major diameter of air bubbles that is 0.8 times or less the thickness of the adhesive layer.

38. The adhesive layer has a deemed density of 0.59 g / cm³. ３ 1.15g / cm or more ３ The adhesive tape according to claim 34, 35, 36, or 37, which is as follows:

39. The adhesive tape according to claim 34, 35, 36, 37, or 38, wherein the adhesive layer has a structure in which no air bubbles are exposed on the surface in the thickness direction.

40. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 or 39, comprising only the adhesive layer.

41. An adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40, which does not have a base material.

42. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 or 39, which has a base material and the adhesive layer is on at least one surface of the base material.

43. The adhesive tape according to claim 34, 35, 36, 37, 38, or 39, wherein the adhesive layer has a foamed structure, and comprises the adhesive layer and a second adhesive layer that does not have a foamed structure on at least one surface of the adhesive layer.

44. When performing an immersion test on the laminate after bonding the adhesive tape to SUS, in which the laminate is immersed for 48 hours in a mixed solution of isopropanol and water in a volume ratio of 7:3 at 65°C and 90% RH, the 180° peel force against SUS at 23°C before the chemical immersion test of the adhesive tape, which was left standing at 65°C and 90% RH for 48 hours, is compared to the 180° peel force against SUS at 23°C after being left standing at 65°C and 90% RH for 48 hours. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, or 43, wherein the ratio of the 180° peel strength of the adhesive tape to SUS at 23°C after a chemical immersion test is 25% or more.

45. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, or 44, used for fixing internal components of electrical and electronic equipment or in-vehicle components.

46. ​​Electronic device comprising the adhesive tape described in claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45.

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