Adhesive tape

Abstract

To provide an adhesive tape having both excellent low temperature adhesiveness and excellent high speed detachability.SOLUTION: An adhesive tape includes an adhesive layer formed by an adhesive composition, where the adhesive layer has a glass transition temperature measured by dynamic viscoelasticity measurement in a measurement temperature range of -40°C or higher and 200°C or lower at a measurement frequency of 1 Hz of 4°C or lower, and the adhesive layer has a half value width of a peak of loss tangent measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz in a measurement temperature range of -40°C or higher and 200°C or lower of 44°C or lower.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Conventionally, pressure-sensitive adhesive tapes having a pressure-sensitive adhesive layer formed using a pressure-sensitive adhesive composition have been widely used to fix components in electronic devices, vehicles, houses, and building materials (e.g., Patent Documents 1 to 3). Specifically, for example, pressure-sensitive adhesive tapes are used to adhere a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to adhere a touch panel module to a display panel module. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-052050 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-021067 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-120876 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, as electronic devices have become more diverse in their applications and are becoming thinner and smaller, the physical properties required for bonding electronic device components have become more diverse, and manufacturing bases for electronic device components are expanding all over the world.

[0005] Because the environmental conditions in regions where manufacturing bases are located vary widely, such as temperature and humidity, and as manufacturing bases continue to expand, conventional adhesive tapes may not be able to be used in environments where they can fully demonstrate their functionality. In conventional adhesive tapes, the adhesive layer softens and the tack improves as the temperature rises, so in environments with a certain temperature, the risk of problems such as peeling occurring when the adhesive tape is applied is reduced. However, in low-temperature environments, the adhesive layer hardens and the tack decreases, so the risk of problems such as peeling occurring when the adhesive tape is applied increases.

[0006] Furthermore, depending on the manufacturing site, the adhesive tape application process may not be automated. In such cases, the adhesive tape application process is performed manually, but because human work is prone to errors when applying the adhesive tape, there is a need for an adhesive tape that is easy to peel and can be reapplied quickly.

[0007] An object of the present invention is to provide a pressure-sensitive adhesive tape that can achieve both excellent low-temperature application properties and excellent high-speed easy peelability. [Means for solving the problem]

[0008] Disclosure 1 is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed using a pressure-sensitive adhesive composition, wherein the pressure-sensitive adhesive layer has a glass transition temperature of 4°C or lower as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and within a measurement temperature range of -40°C or higher and 200°C or lower, and wherein the pressure-sensitive adhesive layer has a half-width of a loss tangent peak of 44°C or lower as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and within a measurement temperature range of -40°C or higher and 200°C or lower. Disclosure 2 is the pressure-sensitive adhesive tape of Disclosure 1, wherein the pressure-sensitive adhesive composition contains a (meth)acrylic copolymer, the (meth)acrylic copolymer has a structural unit derived from an alkyl (meth)acrylate and a structural unit derived from a monomer having a crosslinkable functional group, and the (meth)acrylic copolymer has a content of the structural unit derived from the monomer having a crosslinkable functional group of 0.01 mass % or more and 20 mass % or less. Disclosure 3 is the pressure-sensitive adhesive tape of Disclosure 2, wherein the alkyl (meth)acrylate includes an alkyl (meth)acrylate having a linear alkyl group, and the (meth)acrylic copolymer contains 65 mass% or more of structural units derived from the alkyl (meth)acrylate having the linear alkyl group. Disclosure 4 is the pressure-sensitive adhesive tape of Disclosure 2 or 3, wherein the alkyl (meth)acrylate comprises an alkyl (meth)acrylate having an alkyl group with 6 to 7 carbon atoms, and the (meth)acrylic copolymer contains 65 mass% or more of structural units derived from the alkyl (meth)acrylate having an alkyl group with 6 to 7 carbon atoms. Disclosure 5 is the pressure-sensitive adhesive tape of Disclosure 2, 3, or 4, wherein the alkyl(meth)acrylate contains an alkyl(meth)acrylate having a boiling point of 250° C. or lower. Disclosure 6 is the pressure-sensitive adhesive tape of Disclosure 2, 3, 4, or 5, wherein the alkyl(meth)acrylate contains an alkyl(meth)acrylate that, when made into a homopolymer, has a glass transition temperature of −50° C. or lower. Disclosure 7 is the pressure-sensitive adhesive tape of Disclosure 2, 3, 4, 5, or 6, wherein the alkyl(meth)acrylate includes n-hexyl(meth)acrylate. Disclosure 8 is the pressure-sensitive adhesive tape of Disclosure 2, 3, 4, 5, 6, or 7, wherein the alkyl(meth)acrylate includes n-heptyl(meth)acrylate. The present disclosure 9 is the pressure-sensitive adhesive tape of the present disclosure 2, 3, 4, 5, 6, 7, or 8, wherein the monomer having a crosslinkable functional group includes a hydroxyl group-containing monomer, and the (meth)acrylic copolymer has a content of structural units derived from the hydroxyl group-containing monomer of 0.01 mass% or more and 2.0 mass% or less. Disclosure 10 is the pressure-sensitive adhesive tape of Disclosures 2, 3, 4, 5, 6, 7, 8, or 9, wherein the monomer having a crosslinkable functional group includes a carboxy group-containing monomer, and the (meth)acrylic copolymer has a content of structural units derived from the carboxy group-containing monomer of 0.1 mass% or more and 10 mass% or less. Disclosure 11 is a pressure-sensitive adhesive tape according to Disclosures 2, 3, 4, 5, 6, 7, 8, 9, or 10, wherein the (meth)acrylic copolymer further comprises at least one structural unit selected from the group consisting of structural units derived from monomers having a cyclic ether structure other than an epoxy structure or an oxetane structure, and structural units derived from monomers having a non-cyclic ether structure. Disclosure 12 is the pressure-sensitive adhesive tape of Disclosure 11, wherein the (meth)acrylic copolymer contains 0.01% by mass or more and 50% by mass or less of structural units derived from monomers having a cyclic ether structure other than the epoxy structure and the oxetane structure, and structural units derived from monomers having the acyclic ether structure. Disclosure 13 is the pressure-sensitive adhesive tape of Disclosures 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, wherein the (meth)acrylic copolymer further has a structural unit derived from a monomer having no crosslinkable functional group and having a glass transition temperature of 0°C or higher as a homopolymer. Disclosure 14 is the pressure-sensitive adhesive tape of Disclosure 13, wherein the (meth)acrylic copolymer does not have the crosslinkable functional group and has a content of structural units derived from monomers whose homopolymer has a glass transition temperature of 0°C or higher of 0.1% by mass or more and 70% by mass or less. Disclosure 15 is the pressure-sensitive adhesive tape of Disclosures 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or 14, wherein the (meth)acrylic copolymer has a weight-average molecular weight of 300,000 or more and 1,500,000 or less and a polydispersity index of 7.0 or less. Disclosure 16 is the pressure-sensitive adhesive tape of Disclosures 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, wherein the pressure-sensitive adhesive composition contains a crosslinking agent, and the crosslinking agent comprises at least one selected from the group consisting of an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent. Disclosure 17 is the pressure-sensitive adhesive tape of Disclosure 16, wherein the crosslinking agent includes the isocyanate-based crosslinking agent and the epoxy-based crosslinking agent. Disclosure 18 is the pressure-sensitive adhesive tape of Disclosure 16 or 17, wherein the content of the crosslinking agent in the pressure-sensitive adhesive composition relative to 100 parts by mass of the (meth)acrylic copolymer is 0.01 parts by mass or more and 10 parts by mass or less. Disclosure 19 is the pressure-sensitive adhesive tape of Disclosures 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18, wherein the pressure-sensitive adhesive composition contains a tackifier, and the content of the tackifier in the pressure-sensitive adhesive composition per 100 parts by mass of the (meth)acrylic copolymer is 10 parts by mass or more and 50 parts by mass or less. Disclosure 20 is the pressure-sensitive adhesive tape of Disclosure 19, wherein the tackifier includes at least one selected from the group consisting of a rosin ester tackifier, a terpene tackifier, and a (meth)acrylic tackifier. Disclosure 21 is the pressure-sensitive adhesive tape of Disclosure 20, wherein the tackifier comprises the rosin ester-based tackifier and the terpene-based tackifier. Disclosure 22 is the pressure-sensitive adhesive tape of Disclosure 19, 20, or 21, wherein the tackifier includes a tackifier having a softening point of 80°C or higher and 170°C or lower. Disclosure 23 is the pressure-sensitive adhesive tape of Disclosure 19, 20, 21, or 22, wherein the tackifier includes a tackifier having a hydroxyl value of 20 mgKOH / g or more and 150 mgKOH / g or less. Disclosure 24 is the pressure-sensitive adhesive tape of Disclosures 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 pressure-sensitive adhesive layer has a peak height of loss tangent of 1.50 or more as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of −40°C or more and 200°C or less. Disclosure 25 is a pressure-sensitive adhesive layer having a shear storage modulus of 5.0 × 10 at 23°C measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C to 200°C. 4 Pa or more 25×10 4 25. The pressure-sensitive 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, or 24, wherein the compressive strength is 100 MPa or less. Disclosure 26 is a pressure-sensitive adhesive layer having a shear storage modulus of 3.0 × 10 at 80°C measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C to 200°C. 4The pressure-sensitive adhesive tape of the present 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, or 25, wherein the compressive strength is 100% or less Pa. Disclosure 27 is the pressure-sensitive adhesive tape 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, or 26, wherein the pressure-sensitive adhesive layer has a gel fraction of 20% by mass or more and 70% by mass or less. Disclosure 28 is the pressure-sensitive adhesive tape 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, or 27, wherein the pressure-sensitive adhesive layer has a thickness of 5 μm or more. Disclosure 29 is a pressure-sensitive 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, having a base layer and pressure-sensitive adhesive layers on both sides of the base layer, with the pressure-sensitive adhesive layer being on at least one side of the base layer. Disclosure 30 is the adhesive tape 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, or 28, which does not have a substrate layer. Disclosure 31 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, 29, or 30, in which a 180° peel strength of the adhesive tape from a SUS plate measured after preparing the adhesive tape and the tape in a 0°C environment and leaving them to stand for 5 minutes at 23°C is 10 N / 25 mm or more. The present disclosure 32 is an adhesive tape according to the present 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 used for fixing electronic equipment components or vehicle-mounted components. The present invention will be described in detail below.

[0009] The present inventors investigated adjusting the glass transition temperature and half-width of loss tangent measured by dynamic viscoelasticity measurement in a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer to fall within specific ranges. As a result, they found that it is possible to obtain a pressure-sensitive adhesive layer that can suppress a decrease in tack even at low temperatures, and that is less likely to disperse stress and suppress an increase in adhesive strength during peeling (particularly during high-speed peeling). They also found that the use of a pressure-sensitive adhesive tape having such a pressure-sensitive adhesive layer can achieve both excellent low-temperature adhesion and excellent high-speed easy removability, leading to the completion of the present invention.

[0010] In this specification, the type of each structural unit in the (meth)acrylic copolymer described below and the type of each component in the pressure-sensitive adhesive composition may be one type or two or more types, unless otherwise specified. Furthermore, in this specification, unless otherwise specified, the terms "content ratio" and "content amount" refer to the total content ratio of all types of structural units that define the "content ratio" or, when two or more types of components that define the "content amount" are included, the total content ratio of all types of said structural units and the total content amount of all types of said components.

[0011] The pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer formed using a pressure-sensitive adhesive composition. The glass transition temperature of the pressure-sensitive adhesive layer described below, the half-width of the loss tangent peak of the pressure-sensitive adhesive layer described below, the height of the loss tangent peak of the pressure-sensitive adhesive layer described below, the shear storage modulus of the pressure-sensitive adhesive layer described below, the gel fraction of the pressure-sensitive adhesive layer described below, and the content of biological carbon in the pressure-sensitive adhesive layer described below can be adjusted to the values ​​described below by adjusting the type and content of each component constituting the pressure-sensitive adhesive composition. Examples of methods for forming the pressure-sensitive adhesive layer using the pressure-sensitive adhesive composition include a method in which the pressure-sensitive adhesive composition is applied to a release film or the like, and then the pressure-sensitive adhesive composition is dried by heating, etc. The pressure-sensitive adhesive layer may contain the uncrosslinked pressure-sensitive adhesive composition, or may contain a crosslinked product of the pressure-sensitive adhesive composition.

[0012] The pressure-sensitive adhesive layer has a glass transition temperature (hereinafter sometimes simply referred to as "glass transition temperature of the pressure-sensitive adhesive layer") of 4°C, as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C to 200°C. When the glass transition temperature of the pressure-sensitive adhesive layer is 4°C or less, the pressure-sensitive adhesive layer is less likely to lose tack even in a low-temperature environment, and the pressure-sensitive adhesive tape of the present invention therefore has excellent low-temperature adhesion properties. The upper limit of the glass transition temperature of the pressure-sensitive adhesive layer is preferably 2°C, more preferably 0°C, and even more preferably -2°C. Furthermore, the lower limit of the glass transition temperature of the pressure-sensitive adhesive layer is preferably −25° C. When the glass transition temperature of the pressure-sensitive adhesive layer is −25° C. or higher, the pressure-sensitive adhesive layer does not become too soft at room temperature, thereby providing the pressure-sensitive adhesive tape of the present invention with superior processability and handleability. The lower limit of the glass transition temperature of the pressure-sensitive adhesive layer is more preferably −20° C., even more preferably −18° C., and even more preferably −15° C. In this specification, the "glass transition temperature" refers to the temperature at which a maximum due to micro-Brownian motion appears among the maximum loss tangents (tan δ) obtained by dynamic viscoelasticity measurement. When there are multiple maximum loss tangents, the "glass transition temperature" refers to the temperature at which the lowest maximum loss tangent appears among the maximum loss tangents in the temperature range of -25°C to 50°C.

[0013] Specific methods for adjusting the glass transition temperature of the pressure-sensitive adhesive layer include, for example, a method of using a linear alkyl (meth)acrylate as a constituent monomer of the (meth)acrylic copolymer and adjusting its content ratio, a method of adjusting the content of a tackifier, a method of using a tackifier with a low softening point as a tackifier, adjusting the content of a crosslinking agent or the content ratio of a monomer having a crosslinkable functional group in the (meth)acrylic copolymer, and adjusting the gel fraction of the pressure-sensitive adhesive layer accordingly.

[0014] The pressure-sensitive adhesive layer has an upper limit of the half-width of the peak of the loss tangent (hereinafter sometimes simply referred to as the "loss tangent of the pressure-sensitive adhesive layer"), measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C to 200°C, of ​​44°C. When the half-width of the peak of the loss tangent of the pressure-sensitive adhesive layer is 44°C or less, the pressure-sensitive adhesive layer has a small loss tangent at around room temperature, making it difficult to disperse stress. Therefore, the pressure-sensitive adhesive tape of the present invention is prevented from increasing in adhesive strength when peeled at high speed, and can exhibit excellent high-speed easy releasability. The upper limit of the half-width of the peak of the loss tangent of the pressure-sensitive adhesive layer is preferably 42°C, more preferably 40°C, and even more preferably 38°C. Furthermore, the preferred lower limit of the half-value width of the loss tangent peak of the pressure-sensitive adhesive layer is 20°C. When the half-value width of the loss tangent of the pressure-sensitive adhesive layer is 20°C or more, the pressure-sensitive adhesive does not impair its impact absorption properties, and the pressure-sensitive adhesive tape of the present invention has better drop impact resistance. The more preferred lower limit of the half-value width of the loss tangent of the pressure-sensitive adhesive layer is 23°C, even more preferred is 25°C, and even more preferred is 26°C. In addition, when there are multiple peaks of the loss tangent of the pressure-sensitive adhesive layer, in this specification, the above-mentioned "half width of the peak of the pressure-sensitive adhesive layer" means the half width of the peak at the lowest temperature among the peaks of the loss tangent of the pressure-sensitive adhesive layer in the temperature range of -25°C to 50°C. Furthermore, in this specification, "half width" means the full width at half maximum.

[0015] Specific methods for adjusting the half-value width of the loss tangent peak of the pressure-sensitive adhesive layer include, for example, a method of adjusting the peak height of the loss tangent of the pressure-sensitive adhesive layer, which will be described later, and a method of adjusting the content ratio of a linear alkyl (meth)acrylate, an alkyl (meth)acrylate having an alkyl group having 6 to 7 carbon atoms, an alkyl (meth)acrylate having a glass transition temperature of -50°C or less when made into a homopolymer, or an alkyl (meth)acrylate having a boiling point of 250°C or less, as a constituent monomer of the (meth)acrylic copolymer.

[0016] The pressure-sensitive adhesive layer preferably has a lower limit of 1.50 and an upper limit of 2.0 for the peak height of the loss tangent measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C to 200°C. When the peak height of the loss tangent of the pressure-sensitive adhesive layer is 1.50 or more, the half-value width of the loss tangent of the pressure-sensitive adhesive layer becomes smaller, making it more difficult to disperse stress. Therefore, the pressure-sensitive adhesive tape of the present invention is more prevented from increasing in adhesive strength when peeled at high speed, thereby exhibiting superior high-speed releasability. When the peak height of the loss tangent of the pressure-sensitive adhesive layer is 2.0 or less, the pressure-sensitive adhesive does not impair its impact absorption properties, and the pressure-sensitive adhesive tape of the present invention is therefore superior in drop impact resistance. The half-value width of the loss tangent of the pressure-sensitive adhesive layer is more preferably 1.53, more preferably 1.80, even more preferably 1.55, even more preferably 1.70, and even more preferably 1.57. In addition, when the pressure-sensitive adhesive layer has multiple loss tangent peaks, in this specification, the "peak height of the pressure-sensitive adhesive layer" refers to the height of the peak at the lowest temperature among the loss tangent peaks of the pressure-sensitive adhesive layer in the temperature range of -25°C or higher and 50°C or lower.

[0017] The pressure-sensitive adhesive layer has a shear storage modulus at 23°C measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C to 200°C (hereinafter, may be simply referred to as "shear storage modulus of the pressure-sensitive adhesive layer at 23°C") of preferably 5.0 × 10 4 Pa, with a preferred upper limit of 25×10 4 The pressure-sensitive adhesive layer has a shear storage modulus of 5.0×10 Pa at 23°C. 4 By having a shear storage modulus of 25×10 Pa or more, the pressure-sensitive adhesive layer does not become too soft at room temperature, and therefore the pressure-sensitive adhesive tape of the present invention does not lose its processability or handling properties during use. 4 By setting the shear storage modulus at 23°C to 6.0 x 10 Pa or less, the tack of the pressure-sensitive adhesive layer is less likely to decrease even in a low-temperature environment, and the pressure-sensitive adhesive tape of the present invention has better low-temperature application properties.4 Pa, a more preferable upper limit is 22 × 10 4 Pa, and a more preferable lower limit is 7.0 × 10 4 Pa, and a more preferable upper limit is 20×10 4 It is Pa.

[0018] The pressure-sensitive adhesive layer has a shear storage modulus at 80°C (hereinafter, sometimes simply referred to as "the shear storage modulus of the pressure-sensitive adhesive layer at 80°C") measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C to 200°C) of preferably 3.0 × 10 4 The pressure-sensitive adhesive layer has a shear storage modulus of 3.0×10 Pa at 80°C. 4 By setting the shear storage modulus at 80°C to 2.6 x 10 Pa or less, the pressure-sensitive adhesive layer can be prevented from excessively softening in a high-temperature environment, and therefore the pressure-sensitive adhesive tape of the present invention has superior adhesive strength at high temperatures. 4 Pa, and a more preferable upper limit is 2.3 × 10 4 It is Pa. The preferred lower limit of the shear storage modulus of the pressure-sensitive adhesive layer at 80°C is 0.5 × 10 4 The pressure-sensitive adhesive layer has a shear storage modulus of 0.5×10 Pa at 80°C. 4 When the shear storage modulus at 80°C is 1.0 x 10 Pa or more, the pressure-sensitive adhesive layer has an appropriate tack at room temperature, and therefore the pressure-sensitive adhesive tape of the present invention has excellent adhesion at room temperature. 4 Pa, and a more preferable lower limit is 1.2 × 10 4 Pa, and an even more preferable lower limit is 1.5 × 10 4 It is Pa.

[0019] The pressure-sensitive adhesive layer has a shear storage modulus at −15° C. measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of −40° C. to 200° C. (hereinafter, may be simply referred to as “shear storage modulus of the pressure-sensitive adhesive layer at −15° C.”) of preferably 100×10 6The shear storage modulus of the pressure-sensitive adhesive layer at −15° C. is 100×10 6 By setting the shear storage modulus at -15°C to 50 x 10 Pa or less, the tack of the pressure-sensitive adhesive layer is less likely to decrease even in a low-temperature environment, and the pressure-sensitive adhesive tape of the present invention has better low-temperature application properties. 6 Pa, and a more preferable upper limit is 20×10 6 It is Pa. The lower limit of the shear storage modulus of the pressure-sensitive adhesive layer at −15° C. is not particularly limited, but a preferred lower limit is 0.1×10 6 It is Pa.

[0020] The glass transition temperature, loss tangent, and shear storage modulus of the pressure-sensitive adhesive layer are measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz. Specifically, the pressure-sensitive adhesive layers are first stacked to form a laminate approximately 1 mm thick, which is then cut into a 6 mm wide and 10 mm long specimen. The specimen is then subjected to dynamic viscoelasticity measurement using a dynamic viscoelasticity measuring device in shear mode under a nitrogen atmosphere at a temperature range of -40°C to 200°C, a heating rate of 5°C / min, a frequency of 1 Hz, and a strain of 0.08%. Examples of such dynamic viscoelasticity measuring devices include the DVA-200 (manufactured by IT Instrumentation & Control Co., Ltd.). Furthermore, the half-value width of the loss tangent of the pressure-sensitive adhesive layer and the peak height of the loss tangent of the pressure-sensitive adhesive layer can be obtained from the dynamic viscoelasticity spectrum obtained by the dynamic viscoelasticity measurement.

[0021] The pressure-sensitive adhesive composition preferably contains a (meth)acrylic copolymer. The (meth)acrylic copolymer preferably has a structural unit derived from an alkyl (meth)acrylate. In this specification, the term "(meth)acrylic" means acrylic or methacrylic, and the term "(meth)acrylate" means acrylate or methacrylate.

[0022] The alkyl(meth)acrylate in the structural unit derived from the alkyl(meth)acrylate preferably contains an alkyl(meth)acrylate having a linear alkyl group (hereinafter sometimes referred to as "alkyl(meth)acrylate (a)"), from the viewpoint of easily adjusting the glass transition temperature and half width of the loss tangent of the pressure-sensitive adhesive layer to the above-mentioned ranges.

[0023] Examples of the alkyl (meth)acrylate (a) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, and n-nonyl (meth)acrylate.

[0024] The content of the structural units derived from the alkyl (meth)acrylate (a) in the (meth)acrylic copolymer is preferably 65% ​​by mass or more, and 98% by mass or more. When the content of the structural units derived from the alkyl (meth)acrylate (a) is 65% by mass or more, the glass transition temperature and the half-width of the loss tangent of the pressure-sensitive adhesive layer can be easily adjusted within the above-mentioned ranges. When the content of the structural units derived from the alkyl (meth)acrylate (a) is 98% by mass or less, the (meth)acrylic copolymer can contain structural units derived from the monomer having the crosslinkable functional group. This makes it easier for the pressure-sensitive adhesive layer to form a crosslinked structure, thereby tending to have appropriate bulk strength. The content of the structural units derived from the alkyl (meth)acrylate (a) is more preferably 75% by mass or more, and more preferably 95% by mass or more, and even more preferably 80% by mass or more, and even more preferably 92% by mass or more. The content of the structural unit derived from the alkyl (meth)acrylate (a) can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13C-NMR measurement or the like) and calculation can be performed from the integrated intensity ratio of the hydrogen peak derived from the alkyl (meth)acrylate (a).

[0025] The alkyl (meth)acrylate in the structural unit derived from the alkyl (meth)acrylate preferably includes a (meth)acrylate having an alkyl group having 6 to 7 carbon atoms (hereinafter sometimes referred to as "alkyl (meth)acrylate (b)"), from the viewpoint of making it easier to adjust the half-value width of the loss tangent of the pressure-sensitive adhesive layer to the above-mentioned range and to make it easier to appropriately design the bulk strength.

[0026] Examples of the alkyl (meth)acrylate (b) include n-hexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, 2-methylpentyl (meth)acrylate, 4-methyl-2-pentyl (meth)acrylate, n-heptyl (meth)acrylate, 1-methylhexyl (meth)acrylate, etc. Among these, (meth)acrylates having an alkyl group with 6 carbon atoms are preferred, and n-hexyl (meth)acrylate is more preferred.

[0027] The content of the structural units derived from the alkyl (meth)acrylate (b) in the (meth)acrylic copolymer is preferably 65% ​​by mass or more, and 98% by mass or more. When the content of the structural units derived from the alkyl (meth)acrylate (b) is 65% by mass or more, the glass transition temperature of the pressure-sensitive adhesive layer can be easily adjusted to the above-mentioned range, and the pressure-sensitive adhesive tape of the present invention exhibits excellent low-temperature adhesion. When the content of the structural units derived from the alkyl (meth)acrylate (b) is 98% by mass or less, the (meth)acrylic copolymer can contain structural units derived from the monomer having the crosslinkable functional group. This makes it easier for the pressure-sensitive adhesive layer to form a crosslinked structure, resulting in appropriate bulk strength. The content of the structural units derived from the alkyl (meth)acrylate (b) is more preferably 75% by mass or more, and more preferably 95% by mass or more, and even more preferably 80% by mass or more, and even more preferably 92% by mass or more. The content of the structural unit derived from the alkyl (meth)acrylate (b) can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13 C-NMR measurement or the like) and calculate from the integrated intensity ratio of the hydrogen peak derived from the alkyl (meth)acrylate (b).

[0028] When the (meth)acrylic copolymer contains structural units derived from a (meth)acrylate having an alkyl group containing 7 carbon atoms, the content of the structural units derived from a (meth)acrylate having an alkyl group containing 7 carbon atoms in the (meth)acrylic copolymer is preferably up to 90% by mass. When the content of the structural units derived from a (meth)acrylate having an alkyl group containing 7 carbon atoms is 90% by mass or less, the (meth)acrylic copolymer can contain structural units derived from a monomer having the crosslinkable functional group, which makes it easier for the pressure-sensitive adhesive layer to form a crosslinked structure and therefore tends to have appropriate bulk strength. A more preferred upper limit of the content of the structural units derived from a (meth)acrylate having an alkyl group containing 7 carbon atoms is 75% by mass, and an even more preferred upper limit is 50% by mass. Furthermore, from the viewpoint that the glass transition temperature of the pressure-sensitive adhesive layer can be easily adjusted within the above-mentioned range and the pressure-sensitive adhesive tape of the present invention has better low-temperature application properties, the lower limit of the content of the structural unit derived from a (meth)acrylate having an alkyl group having 7 carbon atoms is preferably 10 mass %, and more preferably 20 mass %.

[0029] The alkyl (meth)acrylate preferably includes, as the alkyl (meth)acrylate (a) and the alkyl (meth)acrylate (b), an alkyl (meth)acrylate having a linear alkyl group having 6 to 7 carbon atoms, that is, at least one selected from the group consisting of n-hexyl (meth)acrylate and n-heptyl (meth)acrylate, and more preferably n-hexyl (meth)acrylate.

[0030] The content of the structural units derived from n-hexyl (meth)acrylate in the (meth)acrylic copolymer is preferably 65% ​​by mass or more at a lower limit and 98% by mass or more at a higher limit. When the content of the structural units derived from n-hexyl (meth)acrylate is 65% by mass or more, the glass transition temperature of the pressure-sensitive adhesive layer can be easily adjusted to the above-mentioned range, and the pressure-sensitive adhesive tape of the present invention has better low-temperature application properties. When the content of the structural units derived from n-hexyl (meth)acrylate is 98% by mass or less, the (meth)acrylic copolymer can contain structural units derived from the monomer having a crosslinkable functional group. This makes it easier for the pressure-sensitive adhesive layer to form a crosslinked structure, thereby tending to have appropriate bulk strength. The content of the structural units derived from n-hexyl (meth)acrylate is more preferably 75% by mass or more at a lower limit and 95% by mass or more at a higher limit, and even more preferably 80% by mass or more at a higher limit and 92% by mass or more at a higher limit. The content of the structural unit derived from n-hexyl (meth)acrylate can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13 C-NMR measurement or the like) and calculate from the integrated intensity ratio of the peak of hydrogen derived from the n-hexyl (meth)acrylate.

[0031] When the (meth)acrylic copolymer contains structural units derived from n-heptyl (meth)acrylate, the content of the structural units derived from n-heptyl (meth)acrylate in the (meth)acrylic copolymer is preferably up to 90% by mass. By having the content of the structural units derived from n-heptyl (meth)acrylate of 90% by mass or less, the (meth)acrylic copolymer can contain structural units derived from the monomer having the crosslinkable functional group, which makes it easier for the pressure-sensitive adhesive layer to form a crosslinked structure, thereby making it easier for the pressure-sensitive adhesive layer to have appropriate bulk strength. The upper limit of the content of the structural units derived from n-heptyl (meth)acrylate is more preferably 75% by mass, and even more preferably 50% by mass. Furthermore, from the viewpoint of making it easier to adjust the glass transition temperature of the pressure-sensitive adhesive layer within the above-mentioned range and making the pressure-sensitive adhesive tape of the present invention have better low-temperature application properties, the lower limit of the content of the structural unit derived from the n-heptyl (meth)acrylate is preferably 10 mass %, and more preferably 20 mass %. The content of the structural unit derived from n-heptyl (meth)acrylate was determined by mass spectrometry of the (meth)acrylic copolymer and 1 H-NMR measurement can be carried out, and the concentration can be calculated from the integrated intensity ratio of the hydrogen peak derived from the n-heptyl (meth)acrylate.

[0032] The alkyl (meth)acrylate preferably contains an alkyl (meth)acrylate having a boiling point of 250°C or lower. By containing an alkyl (meth)acrylate having a boiling point of 250°C or lower, it becomes easier to adjust the half-width of the loss tangent peak of the pressure-sensitive adhesive layer to within the above-mentioned range. The upper limit of the boiling point of the alkyl (meth)acrylate having a boiling point of 250°C or lower is more preferably 220°C, and even more preferably 200°C. Furthermore, the lower limit of the boiling point of the alkyl (meth)acrylate having a boiling point of 250°C or less is preferably 100°C, more preferably 150°C, from the viewpoint of providing an appropriate bulk strength. In this specification, the "boiling point of alkyl (meth)acrylate" means the boiling point at 101 kPa.

[0033] Examples of alkyl (meth)acrylates having a boiling point of 250°C or less include n-butyl acrylate (boiling point: 145°C), n-butyl methacrylate (boiling point: 163°C), n-hexyl acrylate (boiling point: 195°C), n-hexyl methacrylate (boiling point: 88°C), n-heptyl acrylate (boiling point: 222°C), n-heptyl methacrylate (boiling point: 229°C), 1-methylheptyl acrylate (boiling point: 218°C), 1-methylheptyl methacrylate (boiling point: 79°C), 2-ethylhexyl acrylate (boiling point: 215°C), and 2-ethylhexyl methacrylate (boiling point: 214°C). Of these, n-hexyl acrylate and n-hexyl methacrylate are preferred.

[0034] The alkyl (meth)acrylate preferably contains an alkyl (meth)acrylate that has a glass transition temperature of -50°C or lower when made into a homopolymer. By containing an alkyl (meth)acrylate that has a glass transition temperature of -50°C or lower when made into a homopolymer, it becomes easier to adjust the half-value width of the loss tangent peak of the pressure-sensitive adhesive layer to within the above-mentioned range. The upper limit of the glass transition temperature of the alkyl (meth)acrylate that has a glass transition temperature of -50°C or lower when made into a homopolymer is more preferably -55°C, and even more preferably -60°C. Furthermore, the lower limit of the glass transition temperature of the alkyl (meth)acrylate having a glass transition temperature of -50°C or less is preferably -100°C, more preferably -80°C, from the viewpoint of easily having an appropriate bulk strength. In this specification, the term "glass transition temperature when made into a homopolymer" refers to the glass transition temperature measured by differential scanning calorimetry of a homopolymer in which the weight-average molecular weight of the alkyl (meth)acrylate is 100,000 or more and 2,000,000 or less. The glass transition temperature when made into the homopolymer can be measured, for example, in a nitrogen atmosphere (nitrogen flow, flow rate 50 mL / min) using a differential scanning calorimeter (Seiko Instruments Inc., "220C" or the like) according to JIS K6240:2011, at a measurement temperature of -100°C to 200°C and a heating rate of 10°C / min.

[0035] Examples of the alkyl(meth)acrylate having a glass transition temperature of −50° C. or lower when made into a homopolymer include n-butyl acrylate (glass transition temperature when made into a homopolymer: −54° C.), n-hexyl acrylate (glass transition temperature when made into a homopolymer: −65° C.), and n-heptyl acrylate (glass transition temperature when made into a homopolymer: −68° C.). Of these, n-hexyl acrylate is preferred.

[0036] The alkyl (meth)acrylate may include alkyl (meth)acrylates other than the alkyl (meth)acrylate (a), the alkyl (meth)acrylate (b), the alkyl (meth)acrylate having a boiling point of 250°C or less, and the alkyl (meth)acrylate having a glass transition temperature of -50°C or less.

[0037] The alkyl (meth)acrylate may be composed solely of petroleum-derived materials, but preferably contains biologically derived materials. In recent years, the depletion of petroleum resources and carbon dioxide emissions from the combustion of petroleum-derived products have become a major concern, and efforts have been made to conserve petroleum resources by using bio-derived materials instead of petroleum-derived materials. The alkyl (meth)acrylate contains a bio-derived material, which is preferable from the viewpoint of saving petroleum resources. Furthermore, since the bio-derived material is originally produced by absorbing carbon dioxide from the atmosphere, even if it is burned, it is thought that the total amount of carbon dioxide in the atmosphere will not increase, which is also preferable from the viewpoint of reducing carbon dioxide emissions.

[0038] When the alkyl(meth)acrylate in the structural unit derived from the alkyl(meth)acrylate contains a biologically-derived material, the alkyl(meth)acrylate is preferably synthesized by esterifying an alcohol, which is a biologically-derived material, with (meth)acrylic acid. Examples of methods for obtaining the above-mentioned biologically derived alcohol include converting linoleic acid derived from castor oil into linoleic acid hydroperoxide using lipoxygenase, then obtaining a mixture containing n-hexylaldehyde using isomerase, and then distilling the resulting mixture to obtain n-hexylaldehyde containing biologically derived carbon.Furthermore, n-hexyl alcohol containing biologically derived carbon can be obtained inexpensively and easily by hydrogenating the obtained n-hexylaldehyde containing biologically derived carbon.

[0039] The (meth)acrylic copolymer preferably has a structural unit derived from a monomer having a crosslinkable functional group. When the (meth)acrylic copolymer has a structural unit derived from the monomer having a crosslinkable functional group, the pressure-sensitive adhesive layer is more likely to form a crosslinked structure, which makes it easier to have appropriate bulk strength, and therefore the pressure-sensitive adhesive tape of the present invention has better handleability.

[0040] Examples of the monomer having a crosslinkable functional group include a carboxy group-containing monomer, a hydroxy group-containing monomer, a glycidyl group-containing monomer, an amide group-containing monomer, a nitrile group-containing monomer, etc. Among these, the monomer having a crosslinkable functional group preferably includes at least one selected from the group consisting of a carboxy group-containing monomer and a hydroxy group-containing monomer, since this makes it easy to adjust the degree of crosslinking of the pressure-sensitive adhesive composition. The monomer having a crosslinkable functional group preferably has a (meth)acryloyl group. In this specification, the term "(meth)acryloyl" means acryloyl or methacryloyl.

[0041] Examples of the carboxy group-containing monomer include unsaturated monocarboxylic acids such as (meth)acrylic acid, (meth)acryloylacetic acid, (meth)acryloylpropionic acid, (meth)acryloylbutyric acid, (meth)acryloylpentanoic acid, and crotonic acid, and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-methyl-2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1-methyl-2-hydroxypropyl (meth)acrylate, 1-methyl-3-hydroxypropyl (meth)acrylate, 1-ethyl-2-hydroxyethyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 7-hydroxyheptyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 9-hydroxynonyl (meth)acrylate, and polypropylene glycol mono(meth)acrylate. The glycidyl group-containing monomer may, for example, be glycidyl (meth)acrylate. Examples of the amide group-containing monomer include dimethyl(meth)acrylamide, isopropyl(meth)acrylamide, and dimethylaminopropyl(meth)acrylamide. Examples of the nitrile group-containing monomer include (meth)acrylonitrile.

[0042] The preferred lower limit of the content of the structural unit derived from the monomer having a crosslinkable functional group in the (meth)acrylic copolymer is 0.01% by mass, and the preferred upper limit is 20% by mass. When the content of the structural unit derived from the monomer having a crosslinkable functional group is within the above range, the pressure-sensitive adhesive layer is more likely to form a crosslinked structure, which makes it easier to have appropriate bulk strength, resulting in the pressure-sensitive adhesive tape of the present invention being easier to handle. The more preferred lower limit of the content of the structural unit derived from the monomer having a crosslinkable functional group is 0.05% by mass, and the more preferred upper limit is 10% by mass, and even more preferred lower limit is 0.1% by mass, and even more preferred upper limit is 7.0% by mass, and even more preferred lower limit is 1.0% by mass. The content of the structural unit derived from the monomer having a crosslinkable functional group in the (meth)acrylic copolymer can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13 C-NMR measurement or the like) and calculate from the integrated intensity ratio of the hydrogen peak derived from the monomer having the crosslinkable functional group.

[0043] The preferred lower limit of the content of the structural units derived from the hydroxyl group-containing monomer in the (meth)acrylic copolymer is 0.01% by mass, and the preferred upper limit is 2.0% by mass. When the content of the structural units derived from the hydroxyl group-containing monomer is within the above range, the pressure-sensitive adhesive layer is more likely to form a crosslinked structure, which makes it easier to have appropriate bulk strength, resulting in the pressure-sensitive adhesive tape of the present invention being easier to handle. The more preferred lower limit of the content of the structural units derived from the hydroxyl group-containing monomer is 0.05% by mass, more preferably 1.0% by mass, and even more preferably 0.1% by mass. The content of the structural units derived from the hydroxyl group-containing monomer in the (meth)acrylic copolymer can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13 C-NMR measurement or the like) and calculate from the integrated intensity ratio of the hydrogen peak derived from the hydroxyl group-containing monomer.

[0044] The preferred lower limit of the content of the structural units derived from the carboxyl group-containing monomer in the (meth)acrylic copolymer is 0.01% by mass, and the preferred upper limit is 10% by mass. When the content of the structural units derived from the carboxyl group-containing monomer is within the above range, the pressure-sensitive adhesive layer is more likely to form a crosslinked structure, which makes it easier to have appropriate bulk strength, resulting in the pressure-sensitive adhesive tape of the present invention being easier to handle. The more preferred lower limit of the content of the structural units derived from the carboxyl group-containing monomer is 1.0% by mass, and the more preferred upper limit is 8.0% by mass, and the even more preferred lower limit is 3.0% by mass, and the even more preferred upper limit is 6.0% by mass. The content of the structural units derived from the carboxyl group-containing monomer in the (meth)acrylic copolymer can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13 C-NMR measurement or the like) and calculate from the integrated intensity ratio of the hydrogen peak derived from the carboxy group-containing monomer.

[0045] The (meth)acrylic copolymer preferably has at least one structural unit selected from the group consisting of structural units derived from monomers having a cyclic ether structure other than an epoxy structure or an oxetane structure, and structural units derived from monomers having an acyclic ether structure (hereinafter, sometimes simply referred to as "structural units derived from monomers having a non-crosslinkable ether structure"). When the (meth)acrylic copolymer has structural units derived from monomers having a non-crosslinkable ether structure, it becomes easier to design it to have excellent high-speed easy peelability.

[0046] Examples of the monomer having a cyclic ether structure other than the epoxy structure and the oxetane structure include monomers having a cyclic ether structure such as tetrahydrofurfuryl (meth)acrylate. Examples of the monomer having an acyclic ether structure include (meth)acrylates having an acyclic ether structure such as 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and ethyl carbitol (meth)acrylate.

[0047] The content of the structural units derived from the monomer having a non-crosslinkable ether structure in the (meth)acrylic copolymer is preferably 0.01% by mass at the lower limit and 50% by mass at the upper limit. Having a content of the structural units derived from the monomer having a non-crosslinkable ether structure of 0.01% by mass or more facilitates a design that imparts excellent high-speed easy peelability. Having a content of the structural units derived from the monomer having a non-crosslinkable ether structure of 50% by mass or less prevents the glass transition temperature of the pressure-sensitive adhesive layer from increasing too much, thereby further suppressing a decrease in tack even at low temperatures. The content of the structural units derived from the monomer having a non-crosslinkable ether structure is more preferably 0.1% by mass at the lower limit and 30% by mass at the upper limit, even more preferably 1.0% by mass at the lower limit and 20% by mass at the upper limit. The content of the structural unit derived from the monomer having a non-crosslinkable ether structure can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13 C-NMR measurement or the like) and calculation can be performed from the integrated intensity ratio of the hydrogen peak derived from the monomer having the non-crosslinkable ether structure.

[0048] The (meth)acrylic copolymer may contain structural units derived from monomers other than the structural units derived from the alkyl (meth)acrylate, the structural units derived from the monomer having a crosslinkable functional group, and the structural units derived from the monomer having a non-crosslinkable ether structure, within the scope of not impairing the object of the present invention.

[0049] Examples of the other monomers include benzyl (meth)acrylate, etc. Furthermore, examples of the other monomers that can be used include various monomers that are commonly used as raw materials for (meth)acrylic copolymers, such as vinyl acetate and styrene.

[0050] The (meth)acrylic copolymer preferably has a structural unit derived from a monomer that does not have a crosslinkable functional group and that, when made into a homopolymer, has a glass transition temperature of 0° C. or higher. By having the structural unit derived from a monomer that does not have a crosslinkable functional group and that, when made into a homopolymer, has a glass transition temperature of 0° C. or higher, the resulting pressure-sensitive adhesive layer has appropriate bulk strength and is more excellent in retention performance and heat resistance at high temperatures. The monomer having no crosslinkable functional group and having a glass transition temperature of 0°C or higher when made into a homopolymer may be one included in the alkyl(meth)acrylates or a monomer other than the alkyl(meth)acrylates. The monomer having no crosslinkable functional group and having a glass transition temperature of 0°C or higher when made into a homopolymer may be one included in the monomer having an acyclic ether structure or the other monomers.

[0051] Examples of the crosslinkable functional group in the monomer that does not have the above crosslinkable functional group and has a homopolymer Tg of 0° C. or higher include a carboxy group, a hydroxyl group, a glycidyl group, an amide group, and a nitrile group.

[0052] Examples of the monomer that does not have a crosslinkable functional group and has a glass transition temperature of 0°C or higher when made into a homopolymer include n-hexyl methacrylate (glass transition temperature when made into a homopolymer: 0°C), t-butyl acrylate (glass transition temperature when made into a homopolymer: 14°C), t-butyl methacrylate (glass transition temperature when made into a homopolymer: 107°C), cyclohexyl acrylate (homopolymer Tg: 15°C), isobornyl acrylate (homopolymer Tg: 97°C), isobornyl methacrylate (homopolymer Tg: 110°C), tetrahydrofurfuryl methacrylate (homopolymer Tg: 35°C), vinyl acetate (homopolymer Tg: 29°C), and styrene (homopolymer Tg: 100°C).

[0053] The (meth)acrylic copolymer preferably has a lower limit of 0.1% by mass and an upper limit of 70% by mass for the content of structural units derived from a monomer having a glass transition temperature of 0°C or higher when the homopolymer is formed. When the content of structural units derived from a monomer having a glass transition temperature of 0°C or higher when the homopolymer is formed is within this range, the pressure-sensitive adhesive layer has appropriate bulk strength and exhibits superior retention performance and heat resistance at high temperatures. The more preferred lower limit of the content of structural units derived from a monomer having a glass transition temperature of 0°C or higher when the homopolymer is formed is 1.0% by mass and an even more preferred upper limit is 50% by mass. The content of the structural unit derived from a monomer having a glass transition temperature of 0°C or higher when the homopolymer is obtained can be determined by mass spectrometry and / or nuclear magnetic resonance spectroscopy ( 1 H-NMR measurement, 13 C-NMR measurement or the like) and calculate from the integrated intensity ratio of hydrogen peaks derived from a monomer having a glass transition temperature of 0° C. or higher when the homopolymer is obtained.

[0054] The monomer having a crosslinkable functional group, the monomer having a non-crosslinkable ether structure, and other monomers preferably contain biologically derived materials, but may also consist solely of petroleum-derived materials. Theoretically, all of the acrylic monomers constituting the (meth)acrylic copolymer may be monomers containing biologically-derived materials. From the viewpoint of cost and productivity of the pressure-sensitive adhesive composition, it is also possible to adopt a monomer containing a relatively inexpensive and easily available biologically-derived material and combine this with a monomer consisting solely of a petroleum-derived material.

[0055] The weight-average molecular weight of the (meth)acrylic copolymer is not particularly limited and may be, for example, in the range of approximately 30,000 to 2,000,000. The preferred lower limit of the weight-average molecular weight (Mw) of the (meth)acrylic copolymer is 300,000, and the preferred upper limit is 1,500,000. When the weight-average molecular weight of the (meth)acrylic copolymer is within the above range, the pressure-sensitive adhesive layer has appropriate bulk strength, thereby further improving the handleability of the pressure-sensitive adhesive tape of the present invention. The more preferred lower limit of the weight-average molecular weight of the (meth)acrylic copolymer is 500,000, and the more preferred upper limit is 1,400,000, and the even more preferred lower limit is 700,000, and the even more preferred upper limit is 1,300,000.

[0056] Examples of methods for adjusting the weight average molecular weight of the (meth)acrylic copolymer include a method of changing the type or amount of a polymerization initiator or the monomer concentration during the polymerization reaction, a method of adding a small amount of a chain transfer agent such as dodecyl mercaptan, a method of changing the type of polymerization reaction solvent to control chain transfer to the solvent, and a method of changing the temperature and time during the reaction.

[0057] The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the (meth)acrylic copolymer (polydispersity, Mw / Mn) is preferably 7.0. When the polydispersity of the (meth)acrylic copolymer is 7.0 or less, the pressure-sensitive adhesive layer has appropriate bulk strength, thereby further improving the handleability of the pressure-sensitive adhesive tape of the present invention. The more preferred upper limit of the polydispersity of the (meth)acrylic copolymer is 5.0. Furthermore, the polydispersity of the (meth)acrylic copolymer is not particularly limited, but a preferred lower limit is 1.1. When the polydispersity of the (meth)acrylic copolymer is 1.1 or more, tackiness is imparted to the pressure-sensitive adhesive layer, and the low-temperature application property of the pressure-sensitive adhesive tape of the present invention can be further improved. A more preferred lower limit of the polydispersity (Mw / Mn) of the (meth)acrylic copolymer is 2.0.

[0058] The (meth)acrylic copolymer more preferably has a weight-average molecular weight of 300,000 or more and 1,500,000 or less and a polydispersity of 7.0 or less. When the weight-average molecular weight and polydispersity of the (meth)acrylic copolymer satisfy these ranges, the pressure-sensitive adhesive layer has appropriate bulk strength, thereby further improving the handleability of the pressure-sensitive adhesive tape of the present invention.

[0059] In this specification, the weight-average molecular weight is a weight-average molecular weight measured by GPC (gel permeation chromatography) in terms of standard polystyrene. Specifically, a (meth)acrylic copolymer is diluted 50 times with tetrahydrofuran (THF) 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 a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the (meth)acrylic copolymer is measured, and these values ​​are used as the weight-average molecular weight and number-average molecular weight (Mn) of the (meth)acrylic copolymer. An example of the gel permeation chromatograph is the 2690 Separations Module (manufactured by Waters). Furthermore, the polydispersity (Mw / Mn) can be calculated using the obtained weight-average molecular weight (Mw) and number-average molecular weight (Mn).

[0060] The (meth)acrylic copolymer can be obtained by polymerizing a mixture of constituent monomers as raw materials through a radical reaction in the presence of a polymerization initiator. Examples of the radical reaction method include living radical polymerization, free radical polymerization, etc. Living radical polymerization can provide a copolymer having a more uniform molecular weight and composition compared to free radical polymerization, and can suppress the generation of low molecular weight components, etc., so that the resulting pressure-sensitive adhesive composition can exhibit stronger cohesive strength and therefore can exhibit better adhesion to the adherend. The method for polymerizing the monomer mixture can be a conventionally known method, such as solution polymerization (boiling point polymerization or constant temperature polymerization), UV polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, etc. Among these, solution polymerization and UV polymerization are preferred because the resulting pressure-sensitive adhesive composition can exhibit superior adhesion to the adherend. When solution polymerization is used as the method for polymerizing the monomer mixture, examples of the reaction solvent include ethyl acetate, toluene, methyl ethyl ketone, dimethyl sulfoxide, ethanol, acetone, and diethyl ether.

[0061] Examples of the polymerization initiator include organic peroxides and azo compounds. Examples of the 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 the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. Furthermore, when the radical reaction method is the living radical polymerization, the polymerization initiator may be, for example, an organic tellurium polymerization initiator. The organic tellurium polymerization initiator is not particularly limited as long as it is one that is generally used in living radical polymerization, and examples thereof include organic tellurium compounds, organic telluride compounds, etc. Note that, in the living radical polymerization, in addition to the organic tellurium polymerization initiator, the azo compound may also be used for the purpose of accelerating the polymerization rate.

[0062] The preferred lower limit of the content of the (meth)acrylic copolymer in the pressure-sensitive adhesive composition is 50% by mass, and the preferred upper limit is 99.5% by mass. By ensuring that the content of the (meth)acrylic copolymer is within this range, the pressure-sensitive adhesive tape of the present invention can achieve both superior low-temperature application properties and superior high-speed easy peelability. The more preferred lower limit of the content of the (meth)acrylic copolymer is 55% by mass, and the more preferred upper limit is 95% by mass, and the even more preferred lower limit is 70% by mass, and the even more preferred upper limit is 90% by mass, and the even more preferred upper limit is 80% by mass.

[0063] The pressure-sensitive adhesive composition preferably contains a tackifier. By containing a tackifier in the pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer has superior adhesive strength, and peeling of the pressure-sensitive adhesive tape of the present invention can be more effectively prevented.

[0064] The tackifier is not particularly limited, and examples thereof include rosin-based tackifiers, rosin ester-based tackifiers, terpene-based tackifiers, coumarone-indene-based tackifiers, alicyclic saturated hydrocarbon-based tackifiers, C5-based petroleum tackifiers, C9-based petroleum tackifiers, C5-C9 copolymer-based petroleum tackifiers, and (meth)acrylic tackifiers composed of (meth)acrylic compounds. These tackifiers may be used alone or in combination of two or more. Among these, from the viewpoint of low-temperature application properties, at least one selected from the group consisting of rosin ester-based tackifiers, terpene-based tackifiers, and (meth)acrylic tackifiers is preferred, and a rosin ester-based tackifier and a terpene-based tackifier are more preferred.

[0065] Examples of the rosin-based tackifier include rosin-based resins, rosin polyol-based resins, etc. Examples of the rosin ester-based tackifier include polymerized rosin ester-based resins, hydrogenated rosin ester-based resins, etc. Examples of the terpene-based tackifier include terpene-based resins, terpene phenol-based resins, etc. The rosin ester tackifier and the terpene tackifier are preferably derived from a living organism. Examples of the rosin ester tackifier derived from a living organism include a rosin ester tackifier derived from a natural resin such as pine resin. Examples of the terpene tackifier derived from a living organism include a terpene tackifier derived from plant essential oils.

[0066] Specific examples of the rosin ester tackifier include Pencel D-135, Pine Crystal KE-359, Ester Gum AA-V, and Ester Gum H (all manufactured by Arakawa Chemical Industries, Ltd.). Specific examples of the terpene-based tackifier include YS Resin PX1250 and YS Polystar G150 (both manufactured by Yasuhara Chemical Co., Ltd.).

[0067] The (meth)acrylic tackifier is made of a (meth)acrylic compound having a weight average molecular weight of less than 30,000. Examples of the (meth)acrylic compound having a weight-average molecular weight of less than 30,000 include an acrylic oligomer having a weight-average molecular weight of less than 30,000 and an acrylic monomer having a weight-average molecular weight of less than 30,000, and among these, an acrylic oligomer having a weight-average molecular weight of less than 30,000 is preferred.

[0068] The acrylic oligomer having a weight average molecular weight of less than 30,000 used as the (meth)acrylic tackifier has a weight average molecular weight of less than 30,000. Furthermore, the weight-average molecular weight of the acrylic oligomer having a weight-average molecular weight of less than 30,000 is preferably 1,000 or more and less than 30,000. When the weight-average molecular weight of the acrylic oligomer having a weight-average molecular weight of less than 30,000 is within the above range, the adhesive strength of the pressure-sensitive adhesive layer is further improved. The weight-average molecular weight of the acrylic oligomer having a weight-average molecular weight of less than 30,000 is more preferably 1,500 or more and less than 20,000, and even more preferably 2,000 or more and less than 10,000. The weight average molecular weight of the acrylic oligomer having a weight average molecular weight of less than 30,000 can be measured by the same method as the method for measuring the weight average molecular weight of the (meth)acrylic copolymer described above.

[0069] The glass transition temperature of the acrylic oligomer having a weight-average molecular weight of less than 30,000 used as the (meth)acrylic tackifier preferably has a lower limit of 0°C and an upper limit of 300°C. When the glass transition temperature of the acrylic oligomer having a weight-average molecular weight of less than 30,000 is within the above range, the adhesive strength of the pressure-sensitive adhesive layer is further improved. The lower limit of the glass transition temperature of the acrylic oligomer is more preferably 20°C, and even more preferably 40°C. The glass transition temperature of the acrylic oligomer having a weight average molecular weight of less than 30,000 may be, for example, 0°C or higher and 300°C or lower, 20°C or higher and 300°C or lower, or 40°C or higher and 300°C or lower. The glass transition temperature of the acrylic oligomer having a weight-average molecular weight of less than 30,000 can be measured, for example, by differential scanning calorimetry under a nitrogen atmosphere (nitrogen flow, flow rate 50 mL / min) in accordance with JIS K6240:2011 at a measurement temperature of -100°C to 200°C and a heating rate of 10°C / min.

[0070] Examples of the constituent monomers of the acrylic oligomer having a weight-average molecular weight of less than 30,000 and the acrylic monomers having a weight-average molecular weight of less than 30,000 include the same monomers as those used in the constituent units derived from the alkyl(meth)acrylate, the constituent units derived from the monomers having a crosslinkable functional group, the constituent units derived from the monomers having a non-crosslinkable ether structure, and the constituent units derived from the other monomers in the (meth)acrylic copolymer described above.

[0071] Specific examples of the constituent monomers of the acrylic oligomer having a weight average molecular weight of less than 30,000 and the acrylic monomers having a weight average molecular weight of less than 30,000 include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, and isooctyl (meth)acrylate. alkyl (meth)acrylates such as nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate; esters of (meth)acrylic acid and alicyclic alcohols (alicyclic hydrocarbon group-containing (meth)acrylates) such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate; and (meth)acrylates obtained from terpene compound derivative alcohols. The acrylic oligomer having a weight average molecular weight of less than 30,000 preferably contains, as a monomer unit, an acrylic monomer having a relatively bulky structure, typified by alkyl (meth)acrylates having a branched alkyl group such as isobutyl (meth)acrylate and t-butyl (meth)acrylate; esters of (meth)acrylic acid and alicyclic alcohols (alicyclic hydrocarbon group-containing (meth)acrylates) such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; and (meth)acrylates having a cyclic structure such as aryl (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate, from the viewpoint of further improving the adhesiveness of the pressure-sensitive adhesive layer. In addition to the above, monomers having a crosslinkable functional group can be used as constituent monomer components of the acrylic oligomer having a weight-average molecular weight of less than 30,000. Suitable examples of the monomer having a crosslinkable functional group in the acrylic oligomer include monomers having a nitrogen atom-containing ring (typically a nitrogen atom-containing heterocycle) such as N-vinyl-2-pyrrolidone and N-acryloylmorpholine; amino group-containing monomers such as N,N-dimethylaminoethyl (meth)acrylate; amide group-containing monomers such as N,N-diethyl (meth)acrylamide; carboxy group-containing monomers such as acrylic acid and methacrylic acid; and hydroxy group-containing monomers such as 2-hydroxyethyl (meth)acrylate. These functional group-containing monomers can be used alone or in combination of two or more. Among these, carboxy group-containing monomers are preferred, with acrylic acid being particularly preferred. For example, using a carboxy group-containing monomer as the monomer having a crosslinkable functional group can improve adhesion to highly polar adherends. Furthermore, by including a constituent unit derived from the monomer having a crosslinkable functional group as a constituent monomer of the acrylic oligomer having a weight average molecular weight of less than 30,000, the adhesive strength of the pressure-sensitive adhesive layer can be further improved.

[0072] The tackifier preferably contains a tackifier having a softening point of 80°C or higher and 170°C or lower. By containing a tackifier having a softening point of 80°C or higher and 170°C or lower, it becomes easier to adjust the glass transition temperature of the pressure-sensitive adhesive layer to within the above-mentioned range, and the pressure-sensitive adhesive tape of the present invention becomes more excellent in low-temperature application properties. In addition, the pressure-sensitive adhesive tape of the present invention becomes more excellent in heat resistance. The softening point of the tackifier more preferably has a lower limit of 90°C, a more preferred upper limit of 160°C, an even more preferred lower limit of 100°C, and an even more preferred upper limit of 150°C. In this specification, the "softening point" refers to a softening point measured by a method in accordance with JIS K 2207 (ring and ball method).

[0073] The tackifier preferably contains a tackifier having a hydroxyl value of 20 mgKOH / g or more and 150 mgKOH / g or less. By containing a tackifier having a hydroxyl value of 20 mgKOH / g or more and 150 mgKOH / g or less, the degree of crosslinking of the pressure-sensitive adhesive layer is more easily increased, thereby further improving the heat resistance and adherend selectivity of the pressure-sensitive adhesive tape of the present invention. The hydroxyl value of the tackifier is more preferably 30 mgKOH / g (lower limit), 140 mgKOH / g (upper limit), 40 mgKOH / g (lower limit), and 130 mgKOH / g (upper limit). The hydroxyl value can be measured according to JIS K1557 (phthalic anhydride method).

[0074] In the pressure-sensitive adhesive composition, the preferred lower limit of the content of the tackifier relative to 100 parts by mass of the (meth)acrylic copolymer is 10 parts by mass, and the preferred upper limit is 50 parts by mass. When the content of the tackifier is 10 parts by mass or more, the adhesive strength of the pressure-sensitive adhesive layer is further improved, and peeling of the pressure-sensitive adhesive tape of the present invention can be more effectively prevented. When the content of the tackifier is 50 parts by mass or less, it becomes easier to adjust the glass transition temperature of the pressure-sensitive adhesive layer within the above-mentioned range, and the pressure-sensitive adhesive tape of the present invention has better low-temperature application properties. A more preferred lower limit of the content of the tackifier is 20 parts by mass, a more preferred upper limit is 45 parts by mass, an even more preferred lower limit is 30 parts by mass, and an even more preferred upper limit is 40 parts by mass.

[0075] When the pressure-sensitive adhesive composition contains the (meth)acrylic tackifier, the content of the (meth)acrylic tackifier relative to 100 parts by mass of the (meth)acrylic copolymer is preferably 0.1 parts by mass at the lower limit and 50 parts by mass at the upper limit. By ensuring that the content of the (meth)acrylic tackifier is within this range, the low-temperature application properties of the pressure-sensitive adhesive tape of the present invention can be further improved. The content of the (meth)acrylic tackifier is more preferably 1 part by mass at the lower limit and 30 parts by mass at the upper limit.

[0076] The pressure-sensitive adhesive composition preferably contains a crosslinking agent, from the viewpoint of being able to appropriately adjust the degree of crosslinking. Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, and a metal chelate-based crosslinking agent. Among these, from the viewpoint of easily forming a stable crosslinked structure, the crosslinking agent preferably contains at least one selected from the group consisting of an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent, and more preferably contains an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent. When the crosslinking agent contains at least one selected from the group consisting of an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent, the pressure-sensitive adhesive layer more easily forms a crosslinked structure, resulting in appropriate bulk strength and making the pressure-sensitive adhesive tape of the present invention more easy to handle. The crosslinking agent may be used alone or in combination of two or more. When two or more crosslinking agents are used in combination, two or more of the same type of crosslinking agent may be used (for example, two types of isocyanate crosslinking agents may be used), or one or more different types of crosslinking agents may be used in combination (for example, one or more isocyanate crosslinking agents and one or more epoxy crosslinking agents).

[0077] In the pressure-sensitive adhesive composition, the content of the crosslinking agent relative to 100 parts by mass of the (meth)acrylic copolymer is preferably 0.01 parts by mass at the lower limit and 10 parts by mass at the upper limit. When the content of the crosslinking agent is within this range, the pressure-sensitive adhesive layer more easily forms a crosslinked structure, resulting in appropriate bulk strength and superior handleability of the pressure-sensitive adhesive tape of the present invention. The content of the crosslinking agent is more preferably 0.1 parts by mass at the lower limit and 7.0 parts by mass at the upper limit, still more preferably 0.2 parts by mass at the lower limit and 5.0 parts by mass at the upper limit. In this specification, the "content of crosslinking agent" means the content of the solid content of the crosslinking agent.

[0078] The pressure-sensitive adhesive composition may further contain a crosslinking catalyst for accelerating crosslinking by the crosslinking agent. Examples of the crosslinking catalyst include dibutyltin dilaurate, dibutyltin diacetate, and dioctyltin dilaurate as crosslinking catalysts for the isocyanate-based crosslinking agents.

[0079] The pressure-sensitive adhesive composition may contain additives such as a silane coupling agent, a plasticizer, a softener, a filler, a dye, or a pigment, as needed, within the scope of not impairing the object of the present invention.

[0080] The preferred lower limit of the gel fraction of the pressure-sensitive adhesive layer is 20% by mass, and the preferred upper limit is 70% by mass. When the gel fraction of the pressure-sensitive adhesive layer is within the above range, the bulk strength of the pressure-sensitive adhesive layer is further improved, and the pressure-sensitive adhesive tape of the present invention becomes more excellent in handleability. The more preferred lower limit of the gel fraction of the pressure-sensitive adhesive layer is 25% by mass, and the more preferred upper limit is 60% by mass, and even more preferred lower limit is 30% by mass, and even more preferred upper limit is 50% by mass, and even more preferred upper limit is 45% by mass. The gel fraction of the pressure-sensitive adhesive layer is measured by the following method. That is, first, a pressure-sensitive adhesive tape having the pressure-sensitive adhesive layer is cut into a flat rectangular shape of 20 mm wide and 40 mm long to prepare a test piece, and the test piece 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 test piece after drying is measured, and the gel fraction is calculated using the following formula (I). Note that no release film for protecting the pressure-sensitive adhesive layer is laminated on the test piece. Furthermore, when the pressure-sensitive adhesive tape of the present invention is a non-support type tape that does not have a substrate layer, the measurement is performed using a test piece obtained by adhering it to a substrate and cutting it, or the calculation is performed without using a substrate layer, assuming W0 in the following formula (I) to be 0. Gel fraction (mass%) = 100 × (W2 - W0) / (W1 - W0) (I) (W0: Mass of the base layer, W1: Mass of the test piece before immersion, W2: Mass of the test piece after immersion and drying)

[0081] The preferred lower limit of the bio-derived carbon content in the pressure-sensitive adhesive layer is 10%. When the bio-derived carbon content in the pressure-sensitive adhesive layer is 10% or more, the pressure-sensitive adhesive tape of the present invention is excellent in terms of saving petroleum resources and reducing carbon dioxide emissions, and can reduce the environmental burden. The more preferred lower limit of the bio-derived carbon content in the pressure-sensitive adhesive layer is 40%, and the even more preferred lower limit is 60%. Furthermore, the upper limit of the content of bio-derived carbon in the pressure-sensitive adhesive layer is not particularly limited, and may be 100%, but is, for example, 95% or 90%. Biologically derived carbon contains a certain percentage of the radioactive isotope (C-14), whereas petroleum-derived carbon contains almost no C-14. Therefore, the "biologically derived carbon content" in this specification can be calculated by measuring the concentration of C-14 contained in the PSA layer. Specifically, this can be measured in accordance with ASTM D6866-24, a standard widely used in the bioplastics industry.

[0082] The preferred lower limit of the thickness of the pressure-sensitive adhesive layer is 5 μm. When the thickness of the pressure-sensitive adhesive layer is 5 μm or more, the pressure-sensitive adhesive layer has sufficient adhesive strength, and peeling of the pressure-sensitive adhesive tape of the present invention can be more effectively prevented. The more preferred lower limit of the thickness of the pressure-sensitive adhesive layer is 10 μm, and even more preferred lower limit is 15 μm. The upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but a preferred upper limit is 100 μm. By keeping the thickness of the pressure-sensitive adhesive layer at 100 μm or less, an excessive increase in the adhesive strength of the pressure-sensitive adhesive layer is suppressed, and the pressure-sensitive adhesive tape of the present invention can exhibit better high-speed easy peelability. A more preferred upper limit of the thickness of the pressure-sensitive adhesive layer is 75 μm, and an even more preferred upper limit is 50 μm.

[0083] The pressure-sensitive adhesive tape of the present invention may have a layer other than the pressure-sensitive adhesive layer.

[0084] The pressure-sensitive adhesive tape of the present invention may be a non-support type tape that does not have a substrate layer, or a support type tape that has a substrate layer. When the pressure-sensitive adhesive tape of the present invention is a support type tape that has a substrate layer, it may be a single-sided pressure-sensitive adhesive tape that has a pressure-sensitive adhesive layer on one side of the substrate layer, or a double-sided pressure-sensitive adhesive tape that has the pressure-sensitive adhesive layer on at least one side of the substrate layer.

[0085] When the pressure-sensitive adhesive tape of the present invention is a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of a base layer, it is sufficient that the glass transition temperature and half width of the loss tangent of at least one of the pressure-sensitive adhesive layers satisfy the above-mentioned ranges, but it is preferable that the glass transition temperature and half width of the loss tangent of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layers on both sides satisfy the above-mentioned ranges.

[0086] Examples of the substrate used for the substrate layer include a film, a nonwoven fabric, a foam substrate, etc. The substrate used for the substrate layer is preferably a substrate made of a biologically derived material, from the viewpoint of increasing the content of biologically derived carbon in the entire pressure-sensitive adhesive tape. Examples of the above-mentioned biologically-derived materials include polyesters (PES) such as polyethylene terephthalate (PET), polyethylene furanoate (PEF), polylactic acid (PLA), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polybutylene succinate (PBS), polyethylene (PE), polypropylene (PP), polyurethane (PU), triacetyl cellulose (TAC), cellulose, and polyamide (PA), which are derived from plants.

[0087] Furthermore, from the perspective of reducing the use of new petroleum resources and reducing the environmental burden by suppressing carbon dioxide emissions, substrates made from recycled resources may be used. Examples of resource recycling methods include collecting waste materials such as packaging containers, home appliances, automobiles, construction materials, and food, as well as waste generated during manufacturing processes, and then cleaning, decontaminating, or decomposing the extracted materials by heating or fermentation to reuse them as raw materials. Examples of substrates made from recycled resources include films and nonwoven fabrics made from PET, PBT, PE, PP, PA, etc., which are made from recycled plastics that have been re-resinized. Furthermore, collected waste materials may be burned and used as thermal energy for the production of substrates and their raw materials, or the oils and fats contained in the collected waste materials may be mixed with petroleum, fractionated, and purified, and then used as raw materials.

[0088] The substrate used in the substrate layer may include a foam substrate, from the viewpoint of improving the flexibility and low-temperature adhesion of the substrate. The foam substrate is preferably a foam substrate containing at least one selected from the group consisting of PE, PP, and PU, and from the viewpoint of achieving a high degree of both flexibility and strength, a foam substrate containing PE is more preferred. Examples of the constituents of the foam substrate containing PE include PE made from sugarcane.

[0089] A preferred method for producing the foam base material is, for example, to prepare a foamable resin composition containing a PE resin containing sugarcane-derived PE and a foaming agent, and then foam the foaming agent when extruding the foamable resin composition into a sheet using an extruder, and optionally crosslink the resulting polyolefin foam.

[0090] The preferred lower limit of the thickness of the foam substrate is 50 μm, and the preferred upper limit is 5000 μm. By having the thickness of the foam substrate within this range, it is possible to exhibit high impact resistance while also exhibiting high flexibility that allows it to be adhered to the shape of the adherend. The more preferred upper limit of the thickness of the foam substrate is 1000 μm, and even more preferred upper limit is 300 μm.

[0091] The substrate used in the substrate layer is preferably a film containing PES or a film containing PA from the viewpoint of substrate strength, and is preferably a film containing PA from the viewpoint of heat resistance and oil resistance. Examples of the 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.

[0092] The preferred lower limit of the thickness of the substrate is 50 μm, and the preferred upper limit is 5000 μm. By having the thickness of the substrate within this range, the adhesive tape exhibits high flexibility that allows it to be adhered closely to the shape of the adherend and bonded to it, and also has firmness and excellent handleability. The more preferred upper limit of the thickness of the substrate is 1000 μm, and even more preferred upper limit is 300 μm.

[0093] The pressure-sensitive adhesive tape of the present invention has a total thickness (the sum of the thickness of the base layer and the thickness of the pressure-sensitive adhesive layer) of preferably 3 μm at its lower limit and 6000 μm at its upper limit. When the total thickness of the pressure-sensitive adhesive tape of the present invention is within this range, the adhesive strength of the pressure-sensitive adhesive tape of the present invention is further increased. The upper limit of the total thickness of the pressure-sensitive adhesive tape of the present invention is more preferably 1200 μm, and even more preferably 500 μm.

[0094] The method for producing the pressure-sensitive adhesive tape of the present invention is not particularly limited, and the tape can be produced by a conventionally known production method. For example, in the case of a double-sided pressure-sensitive adhesive tape having a substrate, the following method can be mentioned. First, a pressure-sensitive adhesive composition A is prepared by adding a solvent to the (meth)acrylic copolymer and, if necessary, a tackifier, a crosslinking agent, etc. The obtained pressure-sensitive adhesive composition A is applied to the surface of a substrate, and the solvent in the composition is completely dried and removed by heating to form a pressure-sensitive adhesive layer A. Next, a release film is superimposed on the formed pressure-sensitive adhesive layer A with its release-treated surface facing the pressure-sensitive adhesive layer A. Next, a release film separate from the above release film is prepared, and PSA composition B, prepared in the same manner as PSA composition A, is applied to the release-treated surface of this release film. The solvent in the composition is then completely dried and removed to produce a laminate film in which PSA layer B is formed on the surface of the release film. The obtained laminate film is overlaid on the back surface of the substrate on which PSA layer A is formed, with PSA layer B facing the back surface of the substrate to produce a laminate. The laminate is then pressed with a rubber roller or the like to obtain a double-sided PSA tape having PSA layers on both sides of the substrate layer, and the surfaces of the PSA layers covered with release films.

[0095] Alternatively, two sets of laminate films may be prepared in a similar manner, and these laminate films may be superimposed on each of both surfaces of a substrate with the adhesive layer of the laminate film facing the substrate to prepare a laminate. This laminate may then be pressed with a rubber roller or the like to obtain a double-sided adhesive tape having adhesive layers on both surfaces of the substrate layer and the surfaces of the adhesive layers covered with release films.

[0096] The 180° peel strength of the adhesive tape of the present invention from a SUS plate is measured after preparing a SUS plate and the adhesive tape in a 0°C environment and leaving it to stand for 5 minutes, then attaching the adhesive tape to the SUS plate in a 0°C environment and leaving it to stand at 23°C for 5 minutes (hereinafter, this may be simply referred to as the "low-temperature adhesive strength of the adhesive tape"), with the SUS plate. The preferred lower limit is 10 N / 25 mm, and the preferred upper limit is 30 N / 25 mm. When the low-temperature adhesive strength of the adhesive tape is 10 N / 25 mm or more, the adhesive tape of the present invention has superior low-temperature adhesiveness and can further suppress peeling during use in a low-temperature environment. When the low-temperature adhesive strength of the adhesive tape is 30 N / 25 mm or less, the adhesive layer does not become too soft, and the adhesive tape of the present invention has superior handleability. The lower limit of the low-temperature application adhesive strength of the pressure-sensitive adhesive tape is more preferably 12 N / 25 mm, the upper limit is more preferably 25 N / 25 mm, the lower limit is still more preferably 13 N / 25 mm, and the upper limit is still more preferably 20 N / 25 mm. When attaching the adhesive tape to a SUS plate in a 0°C environment, if there is a separator such as a release PET film that protects the adhesive layer of the adhesive tape, the separator on the side of the adhesive tape on which the 180° peel force is measured is peeled off and the adhesive tape is attached to the SUS plate. The low-temperature adhesion strength of the pressure-sensitive adhesive tape is measured by the following method. That is, first, the obtained adhesive tape was cut into a size of 25 mm wide x 100 mm long, and then the release film on one side (the side not being measured) was peeled off, and the exposed adhesive layer was backed with a 50 μm thick PET film (Toyobo Co., Ltd., "E5200#50" or the like) to prepare a test specimen. After the SUS plate and the prepared test specimen were left to stand for 5 minutes in an environment of 0 ° C, the release PET film on the other side (the side to be measured) of the prepared test specimen was peeled off, and the prepared test specimen was pressed against a SUS plate (SUS304 plate washed with alcohol and wiped dry) using a 2 kg rubber roller reciprocating once at a speed of 10 mm / s in an environment of 0 ° C, and then left to stand for 5 minutes in an environment of 23 ° C to prepare a measurement sample. The obtained measurement sample can then be subjected to a peel test in accordance with JIS Z 0237:2009 using a tensile tester (Shimadzu Corporation's "Autograph AGS-X" or the like) at 23°C and a peel rate of 300 mm / min, in which the adhesive tape is peeled off from the SUS plate in a direction of 180°.

[0097] The pressure-sensitive adhesive tape of the present invention may be colored. The color with which the pressure-sensitive adhesive tape of the present invention is colored is not particularly limited, and examples thereof include white, black, gray, etc. Among these, black and gray are preferred from the viewpoint of further improving the light-shielding properties of the pressure-sensitive adhesive tape of the present invention.

[0098] The pressure-sensitive adhesive tape of the present invention can be colored, for example, by adding a pigment (dye) to the pressure-sensitive adhesive composition.

[0099] The use of the pressure-sensitive adhesive tape of the present invention is not particularly limited, but it is preferably used for fixing electronic device components or vehicle-mounted components. Specifically, the pressure-sensitive adhesive tape of the present invention can be suitably used for adhesively fixing electronic device components in large portable electronic devices, adhesively fixing vehicle-mounted components (for example, vehicle-mounted panels), etc. [Effects of the Invention]

[0100] According to the present invention, it is possible to provide a pressure-sensitive adhesive tape that can achieve both low-temperature application properties and high-speed easy peelability. DETAILED DESCRIPTION OF THE INVENTION

[0101] The following examples further illustrate aspects of the present invention, but the present invention is not limited to these examples. The materials used in the examples and comparative examples are as follows.

[0102] <n-Hexyl acrylate containing bio-derived carbon> Linoleic acid derived from castor oil was converted to linoleic acid hydroperoxide using lipoxygenase, and then a mixture containing n-hexylaldehyde was obtained using isomerase. The resulting mixture was distilled to obtain n-hexylaldehyde containing bio-derived carbon. The obtained n-hexylaldehyde containing bio-derived carbon was then hydrogenated to obtain n-hexyl alcohol containing bio-derived carbon. The obtained n-hexyl alcohol containing bio-derived carbon was esterified with acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) to prepare n-hexyl acrylate containing bio-derived carbon.

[0103] <n-heptyl acrylate containing bio-derived carbon> Ricinoleic acid derived from castor oil was cracked to obtain a mixture containing undecylenic acid and n-heptyl alcohol. The undecylenic acid was then separated from the resulting mixture by distillation to obtain n-heptyl alcohol containing bio-derived carbon. The resulting n-heptyl alcohol containing bio-derived carbon was esterified with acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) to prepare n-heptyl acrylate containing bio-derived carbon.

[0104] <1-Methylheptyl acrylate containing bio-derived carbon> Ricinoleic acid derived from castor oil was fused in an alkali to obtain a mixture containing sepacic acid and 1-methylheptyl alcohol. The sepacic acid was then separated from the resulting mixture by distillation to obtain 1-methylheptyl alcohol containing bio-derived carbon. The resulting 1-methylheptyl alcohol containing bio-derived carbon was esterified with acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) to prepare 1-methylheptyl acrylate containing bio-derived carbon.

[0105] <2-hydroxyethyl acrylate containing bio-derived carbon> Ethanol containing bio-derived carbon was obtained by fermenting sugars contained in sugarcane. The obtained bio-derived ethanol was dehydrated to obtain ethylene, which was then oxidized to obtain ethylene oxide, and water was added to obtain ethylene glycol containing bio-derived carbon. The obtained bio-derived ethylene glycol was esterified with acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) to prepare 2-hydroxyethyl acrylate containing bio-derived carbon.

[0106] <Bio-derived carbon-free constituent monomers> 2-Ethylhexyl acrylate (Nippon Shokubai Co., Ltd.) Acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) 2-Methoxyethyl acrylate (Tokyo Chemical Industry Co., Ltd.)

[0107] <Tackifier> Tackifier A: Rosin ester tackifier (softening point: 150°C, hydroxyl value: 35mgKOH / g) Tackifier B: Rosin ester tackifier (manufactured by Arakawa Chemical Industries, Ltd., "KE-359", softening point: 100°C, hydroxyl value: 40 mgKOH / g) Tackifier C: Terpene-based tackifier (terpene phenol-based resin) (Yasuhara Chemical Co., Ltd., "YS Polystar G150", softening point: 150°C, hydroxyl value: 130 mgKOH / g)

[0108] <Crosslinking agent> Isocyanate crosslinking agent (Covestro, "Desmodur L-75") Epoxy crosslinking agent (Mitsubishi Gas Chemical Company, Inc., "Tetrad X")

[0109] Example 1 (1) Preparation of (meth)acrylic copolymer Ethyl acetate was added as a polymerization solvent to a reaction vessel, and nitrogen was bubbled through. The reaction vessel was then heated while nitrogen was flowing in to initiate reflux. Next, a polymerization initiator solution prepared by diluting 0.1 parts by mass of azobisisobutyronitrile 10 times with ethyl acetate was added to the reaction vessel, and 94.9 parts by mass of n-hexyl acrylate containing bio-derived carbon, 0.1 parts by mass of 2-hydroxyethyl acrylate containing bio-derived carbon, and 5.0 parts by mass of acrylic acid were added dropwise over two hours. After the dropwise addition, a polymerization initiator solution prepared by diluting 0.1 parts by mass of azobisisobutyronitrile 10 times with ethyl acetate was added again to the reaction vessel, and the polymerization reaction was carried out for four hours to obtain a (meth)acrylic copolymer-containing solution. The resulting (meth)acrylic copolymer-containing solution was diluted 50-fold with tetrahydrofuran (THF), and the resulting diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm) to prepare a measurement sample. This measurement sample was fed to a gel permeation chromatograph (Waters, "2690 Separations Module") and subjected to GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the (meth)acrylic copolymer was measured, and the weight-average molecular weight and number-average molecular weight were obtained. The obtained weight-average molecular weight and number-average molecular weight were used to calculate the polydispersity. The results are shown in Table 1.

[0110] (2) Manufacturing of adhesive tapes To the resulting (meth)acrylic copolymer-containing solution, 14.0 parts by mass of tackifier A, 10.0 parts by mass of tackifier B, 10.0 parts by mass of tackifier C, and an isocyanate-based crosslinking agent were added so that the solid content of the crosslinking agent was 2.5 parts by mass per 100 parts by mass of the acrylic copolymer in the (meth)acrylic copolymer-containing solution, thereby preparing a pressure-sensitive adhesive composition. The resulting pressure-sensitive adhesive composition was applied to the release-treated surface of a 75 μm-thick release PET film so that the thickness of the pressure-sensitive adhesive layer after drying would be 35 μm, and then dried at 110°C for 5 minutes to form a pressure-sensitive adhesive layer. The resulting pressure-sensitive adhesive layer was then placed on the release-treated surface of a 75 μm-thick release PET film and aged at 40°C for 48 hours to obtain a pressure-sensitive adhesive tape (non-support type).

[0111] (3) Measurement of gel fraction of adhesive layer The release PET film on one side of the resulting adhesive tape was peeled off, and the tape was laminated to a 23 μm thick base PET film (Futamura Chemical Co., Ltd., "FE2002") and cut into a flat rectangular shape 20 mm wide and 40 mm long. The release PET film on the other side of the adhesive tape was then peeled off 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 (% by mass) was calculated using the following formula (I). The results are shown in Table 1. Gel fraction (mass%) = 100 × (W2 - W0) / (W1 - W0) (I) (W0: Mass of the substrate, W1: Mass of the test piece before immersion, W2: Mass of the test piece after immersion and drying)

[0112] (4) Measurement of the glass transition temperature of the adhesive layer The release film of the resulting adhesive tape was peeled off, and the adhesive layers were stacked to form a 1 mm thick laminate, which was then cut into a 6 mm wide and 10 mm long specimen. The resulting specimen was then subjected to dynamic viscoelasticity measurements in shear mode under a nitrogen atmosphere at a temperature range of -40°C to 200°C, a heating rate of 5°C / min, a frequency of 1 Hz, and a strain of 0.08%, to determine the glass transition temperature (°C) of the adhesive layer. The results are shown in Table 1.

[0113] (5) Measurement of the half-width and peak height of the loss tangent of the adhesive layer The half-width (°C) of the loss tangent peak and the height of the loss tangent peak of the pressure-sensitive adhesive layer were obtained from the dynamic viscoelasticity spectrum obtained by the dynamic viscoelasticity measurement at the above-mentioned "(4) Glass transition temperature of the pressure-sensitive adhesive layer." The results are shown in Table 1.

[0114] (6) Measurement of shear storage modulus of adhesive layer The dynamic viscoelasticity measurement at the above-mentioned "(4) Glass transition temperature of the pressure-sensitive adhesive layer" gave the shear storage modulus (Pa) of the pressure-sensitive adhesive layer at -15°C, 23°C, and 80°C. The results are shown in Table 1.

[0115] (Examples 2 to 33, Comparative Examples 1 to 3) Pressure-sensitive adhesive tapes were obtained in the same manner as in Example 1, except that the types and blending amounts of the monomers constituting the (meth)acrylic copolymer and the types and blending amounts of each component of the pressure-sensitive adhesive composition were as shown in Tables 1 to 4. In Examples 21 and 22, the types and blending amounts of the monomers constituting the (meth)acrylic copolymer and the amount of polymerization initiator added were changed as appropriate, and pressure-sensitive adhesive tapes were obtained in the same manner as in Example 1, except that the types and blending amounts of each component of the pressure-sensitive adhesive composition were as shown in Tables 1 to 4. Furthermore, for Examples 2 to 33 and Comparative Examples 1 to 3, the weight average molecular weight of the (meth)acrylic copolymer, the gel fraction of the pressure-sensitive adhesive layer, the glass transition temperature of the pressure-sensitive adhesive layer, the half-width of the loss tangent peak of the pressure-sensitive adhesive layer, the height of the loss tangent peak of the pressure-sensitive adhesive layer, and the shear storage modulus of the pressure-sensitive adhesive layer were measured in the same manner as in Example 1. The results are shown in Tables 1 to 4.

[0116] <Evaluation> The pressure-sensitive adhesive tapes obtained in the examples and comparative examples were evaluated by the following methods, and the results are shown in Tables 1 to 4.

[0117] (low temperature adhesion) (1) Measurement of 180° peel strength against SUS when pressure-sensitive adhesive tape is applied at 0°C The resulting adhesive tape was cut to a size of 25 mm wide x 100 mm long, and the release film on one side (the side not being measured) was peeled off. The exposed adhesive layer was backed with a 50 μm thick PET film (Toyobo Co., Ltd., "E5200#50") to prepare a test specimen. The SUS plate and the prepared test specimen were left standing for 5 minutes in a 0°C environment, and then the release PET film on the other side (the side to be measured) of the prepared test specimen was peeled off. The test specimen was then pressed against a SUS plate (a SUS304 plate that had been washed with alcohol and then wiped dry) using a 2 kg rubber roller reciprocating once at a speed of 10 mm / s in a 0°C environment, and then left standing for 5 minutes in a 23°C environment to prepare a measurement sample. A peel test was performed on the obtained measurement samples in accordance with JIS Z 0237:2009 using a tensile testing machine (Shimadzu Corporation, "Autograph AGS-X") at 23°C and a peel rate of 300 mm / min, in which the adhesive tape was peeled off in a direction of 180° from the SUS plate, and the 180° peel force F1 (N / 25 mm) against the SUS when the adhesive tape was pressed against it at 0°C was measured.

[0118] (2) Measurement of 180° peel strength against SUS when pressure-sensitive adhesive tape is applied at 23°C The 180° peel force F2 (N / 25 mm) against SUS when adhesive tape was adhered at 23°C was measured in the same manner as in "(1) Measurement of 180° peel force against SUS when adhesive tape was adhered at 0°C" above, except that the SUS plate and test piece were not left to stand for 5 minutes in a 0°C environment, and the test piece was pressed against the SUS plate (SUS304 plate that had been washed with alcohol and then wiped dry) by moving a 2 kg rubber roller back and forth once at a speed of 10 mm / s in a 23°C environment.

[0119] (3) Calculation of low-temperature adhesive strength loss rate Using F1 and F2 obtained by the above-mentioned method, the low-temperature adhesion adhesive strength reduction rate (%) was calculated using the following formula (II): Low-temperature adhesion adhesive strength loss rate (%) = {(F2-F1) / F2} x 100 (II) (F1: 180° peel strength from SUS when adhesive tape is applied at 0°C, F2: 180° peel strength from SUS when adhesive tape is applied at 23°C)

[0120] (4) Evaluation of low-temperature adhesion The low-temperature adhesion of the adhesive tape was evaluated as follows: if the calculated low-temperature adhesion adhesive strength reduction rate (%) was 10% or less, it was marked as "◎", if it was more than 10% but not more than 25%, it was marked as "○", if it was more than 25% but not more than 50%, it was marked as "△", and if it was more than 50%, it was marked as "×".

[0121] (High-speed easy peelability) (1) Measurement of 180° peel strength against SUS when adhesive tape is peeled off at a peeling speed of 1500 mm / min The resulting adhesive tape was cut to a size of 25 mm wide x 100 mm long, and the release film on one side (the side not being measured) was peeled off, and the exposed adhesive layer was backed with a 50 μm thick PET film (Toyobo Co., Ltd., "E5200#50") to prepare a test specimen. The release PET film on the other side (the side being measured) of the prepared test specimen was peeled off, and the specimen was pressed against a SUS plate (SUS304 plate that had been washed with alcohol and wiped dry) using a 2 kg rubber roller going back and forth once at a speed of 10 mm / s in an environment of 23°C, and then left to stand in an environment of 23°C for 5 minutes to prepare a measurement sample. A peel test was performed on the obtained measurement samples in accordance with JIS Z 0237:2009 using a tensile testing machine (Shimadzu Corporation, "Autograph AGS-X"), in which the adhesive tape was peeled off from the SUS plate in a direction of 180° at 23°C and a peel rate of 1500 mm / min, and the 180° peel force F3 (N / 25 mm) from the SUS plate when the adhesive tape was peeled off at a peel rate of 1500 mm / min was measured.

[0122] (2) Measurement of 180° peel strength against SUS when adhesive tape is peeled off at a peeling speed of 300 mm / min In the peel test, the 180° peel force F4 (N / 25 mm) against SUS when the adhesive tape was peeled off at a peeling speed of 300 mm / min was measured using the same method as described above in "(1) Measurement of the 180° peel force against SUS when the adhesive tape was peeled off at a peeling speed of 1500 mm / min," except that the adhesive tape was peeled off from the SUS plate at a peeling speed of 300 mm / min.

[0123] (3) Calculation of adhesive strength increase rate during high-speed peeling Using F3 and F4 obtained by the above-mentioned method, the increase rate (%) of adhesive strength during high-speed peeling was calculated using the following formula (III). Adhesive strength increase rate during high-speed peeling (%)={(F3-F4) / F4}×100 (III) (F3: 180° peel force against SUS when adhesive tape is peeled at a peeling speed of 1500 mm / min, F4: 180° peel force against SUS when adhesive tape is peeled at a peeling speed of 300 mm / min)

[0124] (4) Evaluation of high-speed peelability The high-speed removability of the adhesive tape was evaluated as follows: if the calculated adhesive strength increase rate (%) during high-speed peeling was 10% or less, it was marked "◎"; if it was more than 10% and less than 20%, it was marked "○"; if it was more than 20% and less than 30%, it was marked "△"; and if it was more than 30%, it was marked "×".

[0125] [Table 1]

[0126] [Table 2]

[0127] [Table 3]

[0128] [Table 4] [Industrial Applicability]

[0129] According to the present invention, it is possible to provide a pressure-sensitive adhesive tape that can achieve both excellent low-temperature application properties and excellent high-speed easy peelability.

Claims

1. a pressure-sensitive adhesive layer formed using a pressure-sensitive adhesive composition; the pressure-sensitive adhesive layer has a glass transition temperature of 4°C or lower, as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C or higher and 200°C or lower; The pressure-sensitive adhesive layer has a half-width of a loss tangent peak of 44°C or less, as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of -40°C or more and 200°C or less. An adhesive tape characterized by:

2. the pressure-sensitive adhesive composition contains a (meth)acrylic copolymer, The (meth)acrylic copolymer has a structural unit derived from an alkyl (meth)acrylate and a structural unit derived from a monomer having a crosslinkable functional group, The pressure-sensitive adhesive tape according to claim 1 , wherein the (meth)acrylic copolymer contains the structural unit derived from the monomer having a crosslinkable functional group in an amount of 0.01% by mass or more and 20% by mass or less.

3. The alkyl(meth)acrylate includes an alkyl(meth)acrylate having a linear alkyl group, The (meth)acrylic copolymer contains 65% by mass or more of the structural units derived from the alkyl (meth)acrylate having the linear alkyl group. The adhesive tape according to claim 2, wherein

4. The alkyl(meth)acrylate includes an alkyl(meth)acrylate having an alkyl group having 6 to 7 carbon atoms, The (meth)acrylic copolymer contains 65% by mass or more of structural units derived from alkyl (meth)acrylate having an alkyl group having 6 to 7 carbon atoms.

4. The adhesive tape according to claim 2 or 3, wherein

5. The pressure-sensitive adhesive tape according to claim 2 or 3, wherein the alkyl (meth)acrylate contains an alkyl (meth)acrylate having a boiling point of 250°C or lower.

6. 4. The pressure-sensitive adhesive tape according to claim 2, wherein the alkyl (meth)acrylate contains an alkyl (meth)acrylate having a glass transition temperature of −50° C. or lower when made into a homopolymer.

7. 4. The pressure-sensitive adhesive tape according to claim 2, wherein the alkyl(meth)acrylate comprises n-hexyl(meth)acrylate.

8. 4. The pressure-sensitive adhesive tape according to claim 2, wherein the alkyl(meth)acrylate comprises n-heptyl(meth)acrylate.

9. the monomer having a crosslinkable functional group includes a hydroxyl group-containing monomer, The pressure-sensitive adhesive tape according to claim 2 or 3, wherein the (meth)acrylic copolymer contains structural units derived from the hydroxyl group-containing monomer in an amount of 0.01% by mass or more and 2.0% by mass or less.

10. the monomer having a crosslinkable functional group includes a carboxy group-containing monomer, The pressure-sensitive adhesive tape according to claim 2 or 3, wherein the (meth)acrylic copolymer contains structural units derived from the carboxyl group-containing monomer in an amount of 0.1% by mass or more and 10% by mass or less.

11. The pressure-sensitive adhesive tape according to claim 2 or 3, wherein the (meth)acrylic copolymer further comprises at least one structural unit selected from the group consisting of structural units derived from monomers having a cyclic ether structure other than an epoxy structure or an oxetane structure, and structural units derived from monomers having an acyclic ether structure.

12. The pressure-sensitive adhesive tape according to claim 11, wherein the (meth)acrylic copolymer contains 0.01% by mass or more and 50% by mass or less of the structural units derived from the monomer having a cyclic ether structure other than an epoxy structure or an oxetane structure, and the structural units derived from the monomer having a non-cyclic ether structure.

13. The pressure-sensitive adhesive tape according to claim 2 or 3, wherein the (meth)acrylic copolymer further comprises a structural unit derived from a monomer having no crosslinkable functional group and having a glass transition temperature of 0°C or higher as a homopolymer.

14. The pressure-sensitive adhesive tape according to claim 13, wherein the (meth)acrylic copolymer does not have the crosslinkable functional group and has a content of structural units derived from a monomer whose homopolymer has a glass transition temperature of 0°C or higher of 0.1% by mass or more and 70% by mass or less.

15. 4. The pressure-sensitive adhesive tape according to claim 2, wherein the (meth)acrylic copolymer has a weight-average molecular weight of 300,000 or more and 1,500,000 or less and a polydispersity index of 7.0 or less.

16. The pressure-sensitive adhesive composition contains a crosslinking agent, The pressure-sensitive adhesive tape according to claim 2 or 3, wherein the crosslinking agent comprises at least one selected from the group consisting of an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent.

17. The pressure-sensitive adhesive tape according to claim 16 , wherein the crosslinking agent comprises the isocyanate-based crosslinking agent and the epoxy-based crosslinking agent.

18. In the pressure-sensitive adhesive composition, the content of the crosslinking agent relative to 100 parts by mass of the (meth)acrylic copolymer is 0.01 parts by mass or more and 10 parts by mass or less. The adhesive tape according to claim 16.

19. The pressure-sensitive adhesive composition contains a tackifier, In the pressure-sensitive adhesive composition, the content of the tackifier relative to 100 parts by mass of the (meth)acrylic copolymer is 10 parts by mass or more and 50 parts by mass or less. The adhesive tape according to claim 2 or 3.

20. 20. The pressure-sensitive adhesive tape according to claim 19, wherein the tackifier comprises at least one selected from the group consisting of a rosin ester tackifier, a terpene tackifier, and a (meth)acrylic tackifier.

21. The adhesive tape according to claim 20, wherein the tackifier comprises the rosin ester-based tackifier and the terpene-based tackifier.

22. The adhesive tape according to claim 19, wherein the tackifier comprises a tackifier having a softening point of 80°C or higher and 170°C or lower.

23. The pressure-sensitive adhesive tape according to claim 19, wherein the tackifier comprises a tackifier having a hydroxyl value of 20 mgKOH / g or more and 150 mgKOH / g or less.

24. 4. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layer has a peak height of loss tangent of 1.50 or more as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of −40° C. or more and 200° C. or less.

25. The pressure-sensitive adhesive layer has a shear storage modulus of 5.0×10 at 23° C., as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of −40° C. to 200° C. ４ Pa or more 25×10 ４ 4. The adhesive tape according to claim 1, 2 or 3, wherein the viscosity is 0.05 Pa or less.

26. The pressure-sensitive adhesive layer has a shear storage modulus of 3.0×10 at 80° C., as measured by dynamic viscoelasticity measurement at a measurement frequency of 1 Hz and a measurement temperature range of −40° C. to 200° C. ４ 4. The adhesive tape according to claim 1, 2 or 3, wherein the viscosity is 0.05 Pa or less.

27. The pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive layer has a gel fraction of 20% by mass or more and 70% by mass or less.

28. 4. The adhesive tape according to claim 1, wherein the adhesive layer has a thickness of 5 [mu]m or more.

29. A substrate layer and pressure-sensitive adhesive layers on both sides of the substrate layer, 4. The adhesive tape according to claim 1, wherein the adhesive layer is provided on at least one surface of the base layer.

30. The adhesive tape according to claim 1, 2 or 3, which does not have a substrate layer.

31. 4. The adhesive tape according to claim 1, 2 or 3, wherein a 180° peel strength of the adhesive tape from the SUS plate is measured after preparing an SUS plate and the adhesive tape in a 0°C environment, leaving them to stand for 5 minutes, and then attaching the adhesive tape to the SUS plate in a 0°C environment and leaving them to stand at 23°C for 5 minutes, and the 180° peel strength of the adhesive tape from the SUS plate is 10 N / 25 mm or more.

32. The adhesive tape according to claim 1, 2 or 3, which is used for fixing electronic equipment parts or vehicle-mounted parts.

Images