adhesive tape

Abstract

To provide an adhesive tape which can easily peeled off from an adherend surface by extention to a direction horizontal to the adherend surface, even when the adherend surface is a mat surface from which the adhesive tape is difficult to be repeeled due to adhesion enhancing in the lapse of time, while making high load holding force and drop impact resistance, considered as conflicting performances, compatible with each other.SOLUTION: An adhesive tape has a substrate layer and adhesive layers on one face or two faces of the substrate layer. The adhesive layer contains an acrylic block copolymer (X) with storage elastic modulus in a range of 0.10-0.30 MPa and an acrylic block copolymer (Y) with storage elastic modulus in a range of 0.01-0.05 MPa. A content ratio of the acrylic block copolymer (X) to the acrylic block copolymer (Y) is in a range of 90 / 10-30 / 70. The substrate layer has rupture stress in a range of 1-100 MPa and has rupture extensibility of 300-3,000%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Adhesive tapes have excellent workability and high adhesive reliability. Therefore, adhesive tapes are widely used as joining means for fixing components constituting relatively large electronic devices such as flat-screen televisions, home appliances, and office automation equipment, as well as relatively small electronic devices such as mobile electronic terminals, cameras, and personal computers. More specifically, in various industrial fields such as office automation equipment, IT, home appliances, and automobiles, adhesive tapes are used for component fixing applications, such as fixing metal plates or exterior components to housings constituting large electronic devices, and fixing rigid components such as exterior components or batteries to small electronic devices, as well as for temporary fixing of such components, and also for labeling purposes that display product information.

[0003] In recent years, in order to conserve resources and protect the global environment, there has been an increasing trend in the above-mentioned industrial fields to disassemble used products and reuse or recycle the reusable or reusable parts used in the products. In this case, if adhesive tape is used, it is necessary to peel the adhesive tape attached to the parts. However, adhesive tape usually has high adhesive strength and is attached to many parts of the product, so the work of peeling it off involves considerable effort. Therefore, there is a demand for adhesive tape that can be relatively easily peeled and removed when reused or re-used.

[0004] Patent Document 1 is an example of a technology relating to an easily peelable and removable adhesive tape. Patent Document 1 discloses an adhesive tape that has an adhesive portion and a tab portion, and that can be peeled from an adherend attached to both sides of the adhesive portion by clamping the tab portion and stretching it in a direction approximately parallel to the adhesive surface (horizontal direction). Furthermore, when the space between internal components is narrow, as in the case of small electronic devices, it is difficult to stretch and peel an adhesive tape attached to the space in a direction parallel to the adhesive surface. Therefore, Patent Document 2 discloses an adhesive tape that can be removed again by stretching it in a direction 30° to the adhesive surface. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-124289 [Patent Document 2] Special Publication No. 2016-504449 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, peelable and removable adhesive tapes are used to secure components of various devices, from small to large, and therefore must be able to firmly secure the components even when subjected to a heavy load. On the other hand, even when a device with components secured thereto is dropped and subjected to a large impact, the adhesive tape must maintain a securely secured state without peeling from the components. However, it is difficult to achieve both retention properties under a heavy load and drop impact resistance. Improving one property tends to degrade the other property. Therefore, there is a problem in that adhesive tapes cannot fully achieve both retention properties under a heavy load and drop impact resistance.

[0007] Furthermore, for the reuse or re-use of components of various devices, adhesive tapes are required to have the property of being relatively easily peelable and removable. However, when the surface of the adherend is a matte surface, the adhesion is more likely to increase over time than when the surface of the adherend is a smooth surface. Therefore, when the adhesive tape is attached to the matte surface and then stretched horizontally to be peeled off, there are problems such as adhesive residue remaining on the surface of the adherend or the adhesive tape being torn and therefore not being easily peelable. Therefore, adhesive tapes are required to have the properties of high adhesive strength and excellent removability so that the adhesive tape can be easily stretched and peeled off even when the adherend surface is a matte surface, in addition to being able to firmly fix each component.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide an adhesive tape that combines the contradictory properties of high load holding power and drop impact resistance, and that can be easily peeled off by stretching it horizontally against the adherend surface, even on matte surfaces that become difficult to re-peel due to increased adhesion over time. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a pressure-sensitive adhesive tape having a base layer and a pressure-sensitive adhesive layer on one or both sides of the base layer, wherein the pressure-sensitive adhesive layer contains an acrylic block copolymer (X) having a storage modulus in the range of 0.10 MPa to 0.30 MPa and an acrylic block copolymer (Y) having a storage modulus in the range of 0.01 MPa to 0.05 MPa, and the content ratio of the acrylic block copolymer (X) to the acrylic block copolymer (Y) is in the range of 90 / 10 to 30 / 70, and the base layer has a breaking stress in the range of 1 MPa to 100 MPa and a breaking elongation of 300% to 3000%. [Effects of the Invention]

[0010] The present invention can provide an adhesive tape that combines the conflicting properties of high load holding power and drop impact resistance, and that can be easily peeled from an adherend by stretching it horizontally without tearing or leaving adhesive residue on the adherend surface, even if the adherend surface has a matte surface that becomes difficult to re-peel due to increased adhesion over time. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view of an adhesive tape according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic plan view illustrating a test piece used to evaluate drop impact resistance in Examples and Comparative Examples. [Figure 3] FIG. 2 is a schematic diagram illustrating a method for evaluating drop impact resistance in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited to the present embodiment.

[0013] The pressure-sensitive adhesive tape of this embodiment has a base layer and a pressure-sensitive adhesive layer on one or both sides of the base layer. In the pressure-sensitive adhesive tape of this embodiment, the pressure-sensitive adhesive layer contains an acrylic block copolymer (X) having a storage modulus in the range of 0.10 MPa to 0.30 MPa and an acrylic block copolymer (Y) having a storage modulus in the range of 0.01 MPa to 0.05 MPa, and the content ratio of the acrylic block copolymer (X) to the acrylic block copolymer (Y) is in the range of 90 / 10 to 30 / 70. In addition, in the pressure-sensitive adhesive tape of this embodiment, the base layer has a breaking stress in the range of 1 MPa to 100 MPa and a breaking elongation of 300% to 3000%.

[0014] FIG. 1 is a schematic cross-sectional view of a pressure-sensitive adhesive tape according to one embodiment of the present invention, showing an example of a pressure-sensitive adhesive tape 1 having pressure-sensitive adhesive layers 2 on both sides of a base layer 3, wherein the pressure-sensitive adhesive layer 2 contains acrylic block copolymers (X) and (Y) in a predetermined ratio, the acrylic block copolymers having storage moduli in different ranges, and the base layer 3 has predetermined physical properties.

[0015] The pressure-sensitive adhesive tape of this embodiment is a stretch-releasing pressure-sensitive adhesive tape that can be stretched and peeled from a state in which it is adhered to an adherend. According to the pressure-sensitive adhesive tape of this embodiment, the pressure-sensitive adhesive layer provided on the base layer having predetermined physical properties contains two types of acrylic block copolymers with different storage moduli, thereby achieving the contradictory properties of high load holding power and drop impact resistance, and can be easily peeled by stretching the tape horizontally, preventing tearing of the tape and leaving adhesive residue on the adherend, even on smooth surfaces and matte surfaces that become difficult to re-peel due to increased adhesion over time.

[0016]

[0013] More specifically, in the pressure-sensitive adhesive tape of this embodiment, acrylic block copolymers (X) and (Y) having different storage moduli are mixed in a predetermined ratio in the pressure-sensitive adhesive layer, so that the high cohesive strength exerted by the high storage modulus acrylic block copolymer (X) allows the pressure-sensitive adhesive layer to maintain high holding power against high loads, while the impact absorption exerted by the low storage modulus acrylic block copolymer (Y) improves the drop impact resistance of the pressure-sensitive adhesive layer, thereby achieving a balance between high load holding power and drop impact resistance. The present inventors discovered that the combination of the type and storage modulus of the acrylic block copolymer contained in the pressure-sensitive adhesive layer results in differences in high load holding power and drop impact resistance, which led to the present invention.

[0017] Furthermore, when an adhesive tape is applied to an adherend having a matte surface, the adhesive layer is more likely to penetrate the irregularities of the matte surface, resulting in higher adhesion of the adhesive tape to the adherend over time compared to when the adhesive tape is applied to a smooth surface. Therefore, when an adhesive tape applied to a matte surface is stretched horizontally to peel it off from the adherend, a greater force is required, making the tape more likely to tear during the stretching process and leaving adhesive residue on the adherend. In contrast, according to the adhesive tape of the present embodiment, the adhesive layer provided on the base layer having predetermined physical properties is primarily composed of an acrylic block copolymer containing acrylic block copolymers (X) and (Y) having different storage moduli. This ensures strong adhesion even when applied to a matte surface, the adhesion of which tends to increase over time, and is less likely to tear or leave adhesive residue when the adhesive tape is stretched horizontally to peel it off, allowing for easy peeling.

[0018] The pressure-sensitive adhesive tape of this embodiment comprises a pressure-sensitive adhesive layer on at least one surface of a base layer in contact with the base layer. The pressure-sensitive adhesive tape of this embodiment may be a single-sided adhesive tape comprising one pressure-sensitive adhesive layer on one surface of the base layer in contact with the base layer, or a double-sided adhesive tape comprising two pressure-sensitive adhesive layers on both surfaces of the base layer in contact with the base layer. In the double-sided adhesive tape, the pressure-sensitive adhesive layers on each surface of the base layer may be the same or different. In particular, the pressure-sensitive adhesive tape of this embodiment is preferably a double-sided adhesive tape, and the pressure-sensitive adhesive layers on each surface of the base layer each contain an acrylic block copolymer (X) having a storage modulus in the range of 0.10 MPa to 0.30 MPa and an acrylic block copolymer (Y) having a storage modulus in the range of 0.01 MPa to 0.05 MPa, and the content ratio of the acrylic block copolymer (X) to the acrylic block copolymer (Y) is preferably in the range of 90 / 10 to 30 / 70.

[0019] The adhesive tape of this embodiment is not only a general term for a tape having an adhesive layer on one or both sides of a base layer and wound into a roll, but also includes a plate-shaped tape having an adhesive layer on one or both sides of a base layer and having a release liner attached thereto.

[0020] The pressure-sensitive adhesive tape of this embodiment can be peeled by stretching; specifically, it can be peeled from a state in which it is adhered to an adherend by stretching it at least in a direction horizontal to the adherend surface. Here, the horizontal direction refers to a direction in which, when the tape is stretched, the angle (sometimes referred to as the stretching angle) between the surface of the tape facing the adherend and the adherend surface is 0°, i.e., 0° peeling. The pressure-sensitive adhesive tape of this embodiment can be peeled by stretching it at least in a direction horizontal to the adherend surface. However, it is preferable that the pressure-sensitive adhesive tape can be peeled not only in the horizontal direction but also in a direction forming a desired angle with respect to the adherend surface, for example, in the vertical direction, regardless of the surface roughness of the adherend surface. That is, the stretching angle of the pressure-sensitive adhesive tape of this embodiment is preferably in the range of 0° to 90°.

[0021] The pressure-sensitive adhesive tape of this embodiment will be described in detail below.

[0022] 1. Adhesive layer The pressure-sensitive adhesive layer in this embodiment contains an acrylic block copolymer (X) having a storage modulus in the range of 0.10 MPa to 0.30 MPa and an acrylic block copolymer (Y) having a storage modulus in the range of 0.01 MPa to 0.05 MPa, and the pressure-sensitive adhesive layer contains the acrylic block copolymer (X) and the acrylic block copolymer (Y) in a ratio of 90 / 10 to 30 / 70.

[0023] [1] Composition The pressure-sensitive adhesive layer in this embodiment is formed from a pressure-sensitive adhesive composition containing at least a pressure-sensitive adhesive resin. The pressure-sensitive adhesive composition may contain only the pressure-sensitive adhesive resin, or may contain other components in addition to the pressure-sensitive adhesive resin. In this embodiment, the pressure-sensitive adhesive resin essentially contains an acrylic block copolymer.

[0024] The pressure-sensitive adhesive layer and the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer are mainly composed of a pressure-sensitive adhesive resin containing an acrylic block copolymer, where the main component refers to the component contained in the pressure-sensitive adhesive composition in the largest amount, and can be 30% by mass or more, preferably 40% by mass or more, with 50% by mass or more, 60% by mass or more, 70% by mass or more, and 80% by mass or more being particularly preferred.

[0025] <1> adhesive resin The adhesive resin contained in the pressure-sensitive adhesive composition contains an acrylic block copolymer (X) having a storage modulus in the range of 0.10 MPa to 0.30 MPa and an acrylic block copolymer (Y) having a storage modulus in the range of 0.01 MPa to 0.05 MPa in a predetermined ratio. The adhesive resin is mainly composed of an acrylic block copolymer containing the acrylic block copolymer (X) and the acrylic block copolymer (Y).

[0026] The content of the acrylic block copolymer in the adhesive resin should be the highest, and is preferably 50% by mass or more, more preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, and 90% by mass or more, in that order. It is particularly preferable that the content be 100% by mass, i.e., the adhesive resin be composed only of the acrylic block copolymer.

[0027] The total proportion of the acrylic block copolymer (X) and the acrylic block copolymer (Y) in the acrylic block copolymer is preferably 80% by mass or more, and more preferably 90% by mass or more, and is particularly preferably 100% by mass, i.e., the adhesive resin is composed only of the acrylic block copolymer (X) and the acrylic block copolymer (Y). This is because, when the content of the acrylic block copolymer in the adhesive resin and the total proportion of the acrylic block copolymer (X) and the acrylic block copolymer (Y) in the acrylic block copolymer are within the above ranges, the effects of the acrylic block copolymers (X) and (Y) can be fully exhibited.

[0028] In this embodiment, the content ratio (X / Y) of the acrylic block copolymer (X) to the acrylic block copolymer (Y) is within the range of 90 / 10 to 30 / 70. By having the content ratio of the acrylic block copolymer (X) to the acrylic block copolymer (Y) within this range, the conflicting properties of high load holding power and drop impact resistance are both achieved, and even from a matte surface where adhesion increases over time and removability becomes difficult, removability can be easily achieved by stretching. If the content ratio (X / Y) exceeds the upper limit of the above range, the proportion of the acrylic block copolymer (X) increases, resulting in increased cohesive strength of the pressure-sensitive adhesive layer, while the proportion of the acrylic block copolymer (Y) decreases, resulting in insufficient drop impact resistance. On the other hand, if the content ratio (X / Y) is below the lower limit of the above range, the proportion of the acrylic block copolymer (Y) increases, resulting in increased impact absorption of the pressure-sensitive adhesive layer, while the proportion of the acrylic block copolymer (X) decreases, resulting in the pressure-sensitive adhesive layer not achieving the desired cohesive strength, resulting in insufficient high load holding power and removability. The content ratio (X / Y) of the acrylic block copolymer (X) to the acrylic block copolymer (Y) may be within a range of 90 / 10 to 30 / 70, more preferably within a range of 85 / 15 to 35 / 65, and even more preferably within a range of 80 / 20 to 40 / 60. By setting the content ratio (X / Y) of the acrylic block copolymer (X) to the acrylic block copolymer (Y) within the above range, it is possible to further improve the balance between high load retention due to high cohesive strength and impact absorption, and also to obtain good removability when applied to an adherend with a matte surface.

[0029] The content ratio (X / Y) of the acrylic block copolymer (X) to the acrylic block copolymer (Y) is the ratio of the blending amount (parts by mass) of the acrylic block copolymer (X) to the blending amount (parts by mass) of the acrylic block copolymer (Y).

[0030] (1) Acrylic block copolymer (X) The storage modulus of the acrylic block copolymer (X) is preferably in the range of 0.10 MPa to 0.30 MPa, more preferably in the range of 0.13 MPa to 0.27 MPa, and even more preferably in the range of 0.15 MPa to 0.25 MPa. By adjusting the modulus of the acrylic block copolymer (X) to fall within the above range, the cohesive strength of the pressure-sensitive adhesive layer can be increased, thereby achieving high holding power against a high load, and by blending with the acrylic block copolymer (Y) in a predetermined range, excellent compatibility of high load holding power, drop impact resistance, and removability to a matte surface can be achieved.

[0031] The storage modulus of the acrylic block copolymer (X) can be measured at 23°C and a frequency of 1 Hz by using a test piece prepared by applying the acrylic block copolymer (X) to a release liner (Film Vina 75E-0010GT) with an applicator so that the thickness after drying is 50 μm, overlapping the acrylic copolymer (X) layers to a thickness of 2 mm, and then clamping the test piece between parallel plates with a diameter of 7.9 mm attached to a viscoelasticity tester, Ares 2kSTD, manufactured by Rheometrics. The storage modulus of the acrylic block copolymer (X) from the pressure-sensitive adhesive layer can be measured by extracting the acrylic block copolymer (X) from a solution prepared by dissolving the pressure-sensitive adhesive layer in a solvent, and then measuring the storage modulus in the same manner as described above.

[0032] The storage modulus of the acrylic block copolymer (X) can be adjusted, for example, by the weight ratio of the hard block to the soft block (p, q, r in general formula (1) described later). The storage modulus of the acrylic block copolymer (Y) described later can also be adjusted in a similar manner.

[0033] The weight-average molecular weight of the acrylic block copolymer (X) is not particularly limited as long as it is within a range in which the effects of the acrylic block copolymer (X) can be exhibited, but can be 50,000 or more, preferably 60,000 or more, more preferably 70,000 or more, and even more preferably 80,000 or more. The weight-average molecular weight can be 300,000 or less, preferably 150,000 or less, and even more preferably 145,000 or less. More specifically, the weight-average molecular weight of the acrylic block copolymer (Y) is preferably within the range of 50,000 to 300,000, more preferably 60,000 to 300,000, more preferably 70,000 to 150,000, and especially preferably 80,000 to 145,000. When the weight-average molecular weight of the acrylic block copolymer (X) is within the above range, the storage modulus of the acrylic block copolymer (X) can be easily adjusted to a predetermined range, and when blended with the acrylic block copolymer (Y) within the predetermined range, the acrylic block copolymer (X) exhibits excellent high load holding power, drop impact resistance, and removability from a matte surface.

[0034] The number-average molecular weight of the acrylic block copolymer (X) is not particularly limited as long as it is within a range that allows the effects of the acrylic block copolymer (X) to be exhibited, but can be 50,000 or more, preferably 60,000 or more, more preferably 70,000 or more, and even more preferably 80,000 or more. The number-average molecular weight can be 300,000 or less, preferably 150,000 or less, and even more preferably 145,000 or less. More specifically, the number-average molecular weight of the acrylic block copolymer (Y) is preferably within the range of 50,000 to 300,000, more preferably 60,000 to 300,000, more preferably 70,000 to 150,000, and especially preferably 80,000 to 145,000. When the number average molecular weight of the acrylic block copolymer (X) is within the above range, the storage modulus of the acrylic block copolymer (X) can be easily adjusted to a predetermined range, and when blended with the acrylic block copolymer (Y) within the predetermined range, the acrylic block copolymer (X) exhibits excellent high load holding power, drop impact resistance, and removability from a matte surface.

[0035] The weight-average molecular weight and number-average molecular weight of the acrylic block copolymer (X) are values ​​measured by GPC in terms of standard polystyrene, and the measurement conditions are as follows. As a GPC device, for example, "HLC-8329GPC" manufactured by Tosoh Corporation can be used. The weight-average molecular weight and number-average molecular weight of the acrylic block copolymer (Y), which will be described later, can also be measured by the same method. -Measurement conditions- Sample concentration: 0.5% by mass (tetrahydrofuran (THF) solution) Sample injection volume: 100 μL · Eluent: THF · Flow rate: 1.0mL / min · Measurement temperature: 40℃ Column: TSKgel GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0036] The molecular weight distribution (ratio of weight average molecular weight / number average molecular weight) of the acrylic block copolymer (X) is preferably within the range of 1.0 to 2.0, more preferably within the range of 1.0 to 1.7, and even more preferably within the range of 1.0 to 1.5. When the molecular weight distribution of the acrylic block copolymer (X) is within the above range, when it is blended with the acrylic block copolymer (Y) within a predetermined range, the acrylic block copolymer (X) exhibits excellent high load holding power, drop impact resistance, and removability from adherend surfaces, particularly matte surfaces.

[0037] The acrylic block copolymer (X) may be any block copolymer that exhibits a storage modulus within a predetermined range, and may be a diblock copolymer (sometimes referred to as an acrylic diblock copolymer), a triblock copolymer (sometimes referred to as an acrylic triblock copolymer), or a block copolymer with a triblock or higher structure. The acrylic block copolymer (X) may be used alone or in combination with two or more different types. Among these, the acrylic block copolymer (X) is preferably a triblock copolymer having a polymer block [A1] mainly composed of methacrylic acid alkyl ester monomer units and a polymer block [B1] mainly composed of acrylic acid alkyl ester monomer units. This is because using an acrylic triblock copolymer exhibiting a predetermined storage modulus as the acrylic block copolymer (X) can exhibit higher cohesive strength.

[0038] In the acrylic block copolymer (X), the polymer block [A1] mainly composed of methacrylic acid alkyl ester monomer units and the polymer block [B1] mainly composed of acrylic acid alkyl ester monomer units may be abbreviated as polymer block [A1] and polymer block [B1], respectively.

[0039] Furthermore, in this specification, the term "methacrylic acid alkyl ester monomer unit" refers to a structural unit derived from a methacrylic acid alkyl ester monomer when the methacrylic acid alkyl ester monomer is (co)polymerized or graft polymerized, i.e., a repeating unit derived from a methacrylic acid ester monomer. Similarly, in this specification, the term "acrylic acid alkyl ester monomer unit" refers to a structural unit derived from an acrylic acid alkyl ester monomer when the acrylic acid alkyl ester monomer is (co)polymerized or graft polymerized, i.e., a repeating unit derived from an acrylic acid ester monomer.

[0040] The acrylic block copolymer (X) may have a triblock structure, and can be represented by, for example, the following structural formulas (X1) to (X4). [A1]-[B1]-[A1] …(X1) [B1]-[A1]-[A1] …(X2) [B1]-[A1]-[B1] …(X3) [A1]-[B1]-[B1] …(X4) (In the above formulas (X1) to (X4), [A1] represents a polymer block [A1] mainly composed of methacrylic acid alkyl ester monomer units, and [B1] represents a polymer block [B1] mainly composed of acrylic acid alkyl ester monomer units. The two [A1]s in formula (X1) may be the same or different in structure. The two [A1]s in formula (X2) are different in structure. The two [B1]s in formula (X3) may be the same or different in structure. The two [B1]s in formula (X4) are different in structure.) In the structural formulas (X1) to (X4), the polymer block [A1] functions as a hard segment, and the polymer block [B1] functions as a soft segment. Of these, a triblock copolymer represented by the formula (X1) is preferred.

[0041] The polymer block [A1], which is the hard segment, may contain one type of methacrylic acid alkyl ester monomer as a monomer unit, or may contain two or more types of methacrylic acid alkyl ester monomer as a monomer unit. Examples of the methacrylic acid alkyl ester monomer constituting the monomer unit of the polymer block [A1] include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, and 2-hexyldecyl methacrylate. Among these, methyl methacrylate is preferred from the viewpoints of excellent high load holding power and excellent removability and dismantling properties when the adhesive tape is stretched and peeled off.

[0042] The polymer block [B1], which is the soft segment, may contain one type of alkyl acrylate monomer as a monomer unit, or may contain two or more types of alkyl acrylate monomer as monomer units. Examples of alkyl acrylate monomers constituting the monomer units of the polymer block [B1] include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate. Among these, from the viewpoint of achieving both high adhesive strength and good removability, the polymer block [B1] is preferably selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, and copolymers thereof.

[0043] The glass transition temperature of the polymer block [A1] is not particularly limited as long as the acrylic block copolymer (X) can exhibit the desired physical properties, but is, for example, preferably from 20° C. to 150° C., more preferably from 30° C. to 140° C., and even more preferably from 40° C. to 130° C. By setting the glass transition temperature of the polymer block [A1] within the above range, it is possible to achieve excellent high load holding power due to high cohesive strength, and excellent removability and dismantlability when the pressure-sensitive adhesive tape is stretched and peeled off.

[0044] The glass transition temperature of the polymer block [B1] is not particularly limited as long as the acrylic block copolymer (X) can exhibit the desired physical properties, but is preferably, for example, from −80° C. to 40° C., more preferably from −70° C. to 30° C., and even more preferably from −60° C. to 20° C. By setting the glass transition temperature of the polymer block [B1] within the above range, excellent impact resistance can be achieved.

[0045] The glass transition temperatures of the polymer blocks [A1] and [B1] constituting the acrylic block copolymer (X) are the extrapolated onset temperatures of the transition regions of the polymer blocks [A1] and [B1] observed in the curve obtained by analyzing the acrylic block copolymer (X) using a differential scanning calorimeter (DSC). Multiple glass transition temperatures originating from the polymer blocks [A1] and [B1] of the acrylic block copolymer (X) are observed based on the curve obtained by DSC measurement, and the glass transition temperatures originating from each of the polymer blocks [A1] and [B1] can be assigned based on the glass transition temperatures of polymers having similar chemical structures (monomer composition, stereoregularity, etc.) to each polymer block.

[0046] The proportion of the polymer block [A1] in the acrylic block copolymer (X) is preferably within a range of 10% to 30% by mass, more preferably within a range of 14% to 27% by mass, and even more preferably within a range of 18% to 25% by mass, because when the proportion of the polymer block [A1] in the acrylic block copolymer (X) is within the above range, the acrylic block copolymer (X) exhibits excellent high load holding power, drop impact resistance, and removability to a matte surface when blended with the acrylic block copolymer (Y) within a predetermined range. When two or more types of polymer blocks [A1] are contained in one acrylic block copolymer (X), the proportion of the polymer blocks [A1] in the acrylic block copolymer (X) means the proportion of the total mass of the polymer blocks [A1] in the mass of the acrylic block copolymer (X).

[0047] The proportion of the polymer block [B1] in the acrylic block copolymer (X) is preferably within the range of 70% to 90% by mass, more preferably within the range of 73% to 86% by mass, and even more preferably within the range of 75% to 82% by mass. When the proportion of the polymer block [B1] in the acrylic block copolymer (X) is within the above range, the acrylic block copolymer (X) exhibits excellent high-load holding power, drop impact resistance, and removability from a mat surface when blended with the acrylic block copolymer (Y) within a predetermined range. When two or more types of polymer blocks [B1] are contained in one acrylic block copolymer (X), the proportion of the polymer block [B1] in the acrylic block copolymer (X) refers to the proportion of the total mass of the polymer blocks [B] in the mass of the acrylic block copolymer (X).

[0048] The acrylic block copolymer (X) may be modified, if necessary, in the molecular side chain or at the molecular main chain terminal with a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, or a trimethoxysilyl group, as long as the effects of the present invention are not impaired.

[0049] More specifically, preferred examples of the acrylic block copolymer (X) include triblock copolymers having a repeating unit represented by the following general formula (1).

[0050] [ka]

[0051] (In the above general formula (1), A, B, and C each independently represent a repeating unit, A and C each independently represent a methacrylic acid alkyl ester monomer unit, B represents an acrylic acid alkyl ester monomer unit, p, q, and r each independently represent the degree of polymerization of each monomer unit, and A and C may be methacrylic acid alkyl ester monomer units having the same chemical structure or may be methacrylic acid alkyl ester monomer units having different chemical structures. In the above general formula (1), * is a bond representing a bond to another atom.)

[0052] In the general formula (1), A and C represent repeating units different from B, and each represents a methacrylic acid alkyl ester monomer unit. A and C in the general formula (1) constitute the polymer block [A1] in the acrylic block copolymer (X). That is, "-(A)" in the general formula (1) p The polymer block of the "-" part and the "-(C) r The polymer blocks in the "-" portion correspond to the polymer block [A1] in the acrylic block copolymer (X). A and C in the general formula (1) are each independent and may be the same methacrylic acid alkyl ester monomer unit or may be methacrylic acid alkyl ester monomer units having different chemical structures. That is, the polymer block [A1] in the acrylic block copolymer (X) may contain a polymer block of one type of structure, or may contain polymer blocks of two or more different structures.

[0053] The methacrylic acid alkyl ester monomer units in A and C in general formula (1) are preferably represented by the following general formula (2).

[0054] [ka]

[0055] (In the above general formula (2), R 1 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituted by a substituent R 2 and the substituent R 2 represents a halogen atom, an amino group, or a cyano group.

[0056] In the above general formula (2), R 1 From the viewpoint of removability and high load holding power, R is more preferably an alkyl group having 1 to 12 carbon atoms, and even more preferably an alkyl group having 1 to 4 carbon atoms. 1 The C1-12 alkyl group may be linear, branched, or cyclic, and from the viewpoint of adhesive strength, linear or branched is preferred, with linear being more preferred. Examples of the C1-12 alkyl group include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, hexyl, octyl, nonyl, decyl, undecyl, and dodecyl, as well as cyclic alkyl groups such as cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and dicyclopentanyl. Examples of the C1-4 alkyl group include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and t-butyl, as well as cyclic alkyl groups such as cyclobutyl. As the alkyl group having 1 to 4 carbon atoms, from the viewpoint of removability and high load holding power, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group is preferred, and a methyl group is more preferred.

[0057] Preferred R in the above general formula (2) 1is an alkyl group selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and a cyclobutyl group, and one or more hydrogen atoms in the alkyl group are substituted by a substituent R 2 It may be substituted with (a halogen atom, an amino group, a cyano group).

[0058] In A and C in the above general formula (1), the specific monomers constituting the methacrylic acid alkyl ester monomer units can be the same as the methacrylic acid alkyl ester monomers constituting the monomer units of the above-mentioned polymer block [A1].

[0059] In the general formula (1), B represents a repeating unit different from A and C, and represents an acrylic acid alkyl ester monomer unit. B in the general formula (1) constitutes the polymer block [B1] in the acrylic block copolymer (X). That is, "-(B)" in the general formula (1) q The polymer block in the "-" portion corresponds to the polymer block [B1] in the acrylic block copolymer (X).

[0060] The acrylic acid alkyl ester monomer unit in B in general formula (1) is preferably represented by the following general formula (3).

[0061] [ka]

[0062] (In the above general formula (3), R 3 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituted by a substituent R 4 and the substituent R 4 represents a halogen atom, an amino group, or a cyano group.

[0063] In the above general formula (3), R 3From the viewpoint of adhesiveness, the alkyl group is more preferably an alkyl group having 1 to 12 carbon atoms, and even more preferably an alkyl group having 4 to 8 carbon atoms. The alkyl group may be linear, branched, or cyclic, and from the viewpoint of adhesiveness, linear or branched groups are preferred.

[0064] In the above general formula (3), examples of the alkyl group having 1 to 12 carbon atoms are the same as the examples of the alkyl group having 1 to 12 carbon atoms in the above general formula (2).

[0065] Preferred R in the above general formula (3) 3 is an alkyl group selected from the group consisting of n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, hexyl, octyl, cyclohexyl, cycloheptyl, and cyclooctyl, and one or more hydrogen atoms in the alkyl group are substituted by the substituent R 4 It may be substituted with (a halogen atom, an amino group, a cyano group).

[0066] In B in the above general formula (1), the specific monomer constituting the acrylate alkyl ester monomer unit can be the same as the acrylate alkyl ester monomer constituting the monomer unit of the above-mentioned polymer block [B1].

[0067] In the general formula (1), p, q, and r each independently represent the degree of polymerization of each monomer unit. The values ​​of p, q, and r are related to the molecular weight, etc. p / (p+q+r) is preferably 0.06 to 0.20, more preferably 0.11 to 0.16. q / (p+q+r) is preferably 0.61 to 0.88, more preferably 0.68 to 0.77. r / (p+q+r) is preferably 0.06 to 0.20, more preferably 0.11 to 0.16. By setting p / (p+q+r), q / (p+q+r), and r / (p+q+r) within the above ranges, the triblock acrylic block copolymer (X) can ensure a high storage modulus and exhibit high cohesive strength, thereby improving the holding power of the pressure-sensitive adhesive layer, especially when a high load is applied. Furthermore, the removability over time can be improved, not only from smooth surfaces but also from matte surfaces.

[0068] A and C in general formula (1) may be the same repeating unit or different repeating units, but it is preferable that A and C in general formula (1) are the same repeating unit. In other words, it is preferable that the acrylic block copolymer (X) is represented by the above formula (X1), and is a triblock copolymer in which the two [A1]s in formula (X1) are the same (have the same structure). This is because a higher storage modulus can be ensured, making it easier to ensure high load holding power, removability over time, and adhesive strength excellent in storage stability. Specifically, when the acrylic block copolymer (X) has a repeating unit represented by general formula (4) described below, R 1 and R 5 and are the same group, p / (p+q+r) is 0.06 to 0.20, q / (p+q+r) is 0.61 to 0.88, and r / (p+q+r) is 0.06 to 0.20.

[0069] When A and C in the general formula (1) are different repeating units, the "-(A)" contained in the molecule of the triblock copolymer represented by the general formula (1) is p - Total weight of polymer blocks (of the said "-(A) pThe total weight of the polymer blocks is referred to as "-(B)" q - Total weight of polymer blocks of the "-(B)" part q The total weight of the polymer blocks of the - portion is referred to as b. From the viewpoint of adhesive properties, the mass ratio of a / b is preferably within the range of 5 / 90 to 15 / 70, more preferably within the range of 9 / 82 to 12 / 75.

[0070] In addition, when A and C in the general formula (1) are different repeating units, the "-(C)" contained in the molecule of the triblock copolymer represented by the general formula (1) is r - Total weight of polymer blocks of the "-(C)" part r The total weight of the polymer blocks is referred to as "-(B)" q The proportion of the "-" portion to the total weight of the polymer blocks is preferably in the range of 5 / 90 to 15 / 70, more preferably 9 / 82 to 12 / 75, in terms of the mass ratio c / b, from the viewpoint of adhesive properties.

[0071] When A and C in the general formula (1) are the same repeating unit, when A and C in the general formula (1) are the same repeating unit, "-(A)" contained in the molecule of the triblock copolymer (X) p The polymer block of the "-" part and the "-(C) r - Total weight of polymer blocks (-(A) p The polymer block of the "-" part and the "-(C) r The total weight of the polymer blocks is referred to as "-(B)" q The ratio (d / b) of the - portion to the total weight (referred to as b) of the polymer blocks can be the same as the weight ratio calculated from the weights of the polymer block [A1] and the polymer block [B1] in the acrylic block copolymer (X). Specifically, d / b can be within a range of 10 / 90 to 30 / 70, preferably within a range of 14 / 86 to 27 / 73, and more preferably within a range of 18 / 82 to 25 / 75. In addition, when A and C in the general formula (1) are the same repeating unit, it is said that "(A) pThe total weight of the polymer blocks of the - part and -(C) r The sum of the weight of the "-" portion and the total weight of the polymer blocks is the weight of the polymer block [A1] in the acrylic block copolymer (X).

[0072] The acrylic block copolymer (X) preferably has a repeating unit represented by the following general formula (4).

[0073] [ka]

[0074] (In the above general formula (4), R 1 and R 5 each independently represents an alkyl group having 1 to 4 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituted by a substituent R 2 may be substituted with, and the substituent R 2 represents a halogen atom, an amino group, or a cyano group; R 3 represents an alkyl group having 4 to 8 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituted by a substituent R 4 may be substituted with, and the substituent R 4 represents a halogen atom, an amino group, or a cyano group, and p, q, and r each independently represent the degree of polymerization of each monomer unit.

[0075] In the above general formula (4), R 1 is R in the above general formula (2). 1 In the above general formula (4), R 3 is R in the above general formula (3). 3 In the above general formula (4), R 5 is R in the above general formula (2). 1 The same aspects as above can be applied.

[0076] In addition, in the general formula (4), p, q, and r can be applied in the same manner as p, q, and r in the general formula (1). 1 and R5 may be the same or different.

[0077] In the above general formula (4), R 1 is preferably selected from the group consisting of linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and t-butyl groups, and cyclobutyl groups. 3 is preferably selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, hexyl, octyl, nonyl, decyl, or undecyl groups. 5 is preferably selected from the group consisting of linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and t-butyl groups, and cyclobutyl groups. 1 , R 3 and R 5 When are each selected from the above functional group group, it is preferable that p / (p+q+r) in the above general formula (4) is 0.06 to 0.20, q / (p+q+r) is 0.61 to 0.88, and r / (p+q+r) is 0.06 to 0.20.

[0078] The triblock copolymer that can be the acrylic block copolymer (X) is not particularly limited as long as it has the physical properties of the acrylic block copolymer (X), but preferred forms of the triblock copolymer include polymethyl methacrylate block-polyn-butyl acrylate block-polymethyl methacrylate, polyethyl methacrylate block-polyn-butyl acrylate block-polyethyl methacrylate, polypropyl methacrylate block-polyn-butyl acrylate block-polypropyl methacrylate, polymethyl methacrylate block-polyt-butyl acrylate block-polymethyl methacrylate, polymethyl methacrylate block-polypropyl acrylate block-polymethyl methacrylate, etc. Among the above, polymethyl methacrylate block-polyn-butyl acrylate block-polymethyl methacrylate is preferred because it is more likely to exhibit the effects of the acrylic block copolymer (X).

[0079] (2) Acrylic block copolymer (Y) The storage modulus of the acrylic block copolymer (Y) is preferably in the range of 0.01 MPa to 0.05 MPa, more preferably in the range of 0.01 MPa to 0.04 MPa, and even more preferably in the range of 0.01 MPa to 0.03 MPa. By setting the storage modulus of the acrylic block copolymer (Y) within the above range, the pressure-sensitive adhesive layer further enhances the impact absorption effect derived from the acrylic block copolymer (Y), and excellent compatibility of high load holding power, drop impact resistance, and removability to matte surfaces is achieved by blending with the acrylic block copolymer (X) in a predetermined range.

[0080] The storage modulus of the acrylic block copolymer (Y) can be measured by the same method as the above-mentioned method for measuring the storage modulus of the acrylic block copolymer (X).

[0081] The storage modulus of the acrylic block copolymer (Y) from the pressure-sensitive adhesive layer can be measured by the same method as the above-mentioned method for measuring the storage modulus of the acrylic block copolymer (X) from the pressure-sensitive adhesive layer.

[0082] The weight-average molecular weight of the acrylic block copolymer (Y) is not particularly limited as long as it is within a range that allows the effects of the acrylic block copolymer (Y) to be exhibited. However, it is preferably 30,000 or more, more preferably 40,000 or more, and even more preferably 50,000 or more. The weight-average molecular weight is preferably 200,000 or less, more preferably 150,000 or less, even more preferably 100,000 or less, and even more preferably 80,000 or less. More specifically, the weight-average molecular weight of the acrylic block copolymer (Y) is preferably within the range of 30,000 to 200,000, more preferably 40,000 to 200,000, and even more preferably 50,000 to 200,000. When the weight-average molecular weight of the acrylic block copolymer (Y) is within the above range, excellent high-load holding power, drop impact resistance, and removability from a matte surface are achieved when blended with the acrylic block copolymer (X) within a predetermined range.

[0083] The number-average molecular weight of the acrylic block copolymer (Y) is not particularly limited as long as it is within a range that allows the effects of the acrylic block copolymer (Y) to be exhibited. However, it is preferably 30,000 or more, more preferably 40,000 or more, and even more preferably 50,000. The number-average molecular weight is preferably 200,000 or less, more preferably 150,000 or less, even more preferably 100,000 or less, and even more preferably 80,000 or less. More specifically, the number-average molecular weight of the acrylic block copolymer (Y) is preferably within the range of 30,000 to 200,000, more preferably 40,000 to 200,000, and even more preferably 50,000 to 200,000. When the number-average molecular weight of the acrylic block copolymer (Y) is within the above range, excellent high-load holding power, drop impact resistance, and removability from a matte surface are achieved when blended with the acrylic block copolymer (X) within a predetermined range.

[0084] The weight average molecular weight of the acrylic block copolymer (Y) can be measured by the same method as the method for measuring the weight average molecular weight of the acrylic block copolymer (X) described above.

[0085] The molecular weight distribution (ratio of weight average molecular weight / number average molecular weight) of the acrylic block copolymer (Y) is preferably in the range of 1.0 to 2.0, more preferably in the range of 1.0 to 1.7, and even more preferably in the range of 1.0 to 1.5. When the molecular weight distribution of the acrylic block copolymer (Y) is in the above range, blending with the acrylic block copolymer (X) in a predetermined range results in excellent high load holding power, drop impact resistance, and removability to a matte surface.

[0086] The acrylic block copolymer (Y) may be any block copolymer having a storage modulus within the above-mentioned range, and may be a diblock copolymer or a triblock or higher block copolymer. The acrylic block copolymer (Y) may be used alone or in combination with two or more different types. Among these, the acrylic block copolymer (Y) is preferably a triblock copolymer or a diblock copolymer having a polymer block [A2] mainly composed of methacrylic acid alkyl ester monomer units and a polymer block [B2] mainly composed of acrylic acid alkyl ester monomer units. The acrylic block copolymer (Y) may contain only a diblock copolymer, only a triblock copolymer, or both a diblock copolymer and a triblock copolymer. Among these, the acrylic block copolymer (Y) is preferably a triblock copolymer, since it is more likely to exhibit a predetermined storage modulus and more likely to exhibit the effects of the hard segment and the soft segment.

[0087] In the acrylic block copolymer (Y), the polymer block [A2] mainly composed of methacrylic acid alkyl ester monomer units and the polymer block [B2] mainly composed of acrylic acid alkyl ester monomer units may be abbreviated as polymer block [A2] and polymer block [B2], respectively.

[0088] The diblock acrylic block copolymer (Y) can be represented by, for example, the following structural formula (Y1). [A2]-[B2] …(Y1) The triblock acrylic block copolymer (Y) can be represented by, for example, the following structural formulas (Y2) to (Y5). [A2]-[B2]-[A2] …(Y2) [B2]-[A2]-[A2] …(Y3) [B2]-[A2]-[B2] …(Y4) [A2]-[B2]-[B2] …(Y5) (In the above formulas (Y1) to (Y5), [A2] represents a polymer block mainly composed of methacrylic acid alkyl ester monomer units, and [B2] represents a polymer block mainly composed of acrylic acid alkyl ester monomer units. The two [A2]s in formula (Y2) may be the same or different in structure. The two [A2]s in formula (Y3) are different in structure. The two [B2]s in formula (Y4) may be the same or different in structure. The two [B1]s in formula (Y5) are different in structure.) In the structural formulas (Y1) to (Y5), the polymer block [A2] functions as a hard segment, and the polymer block [B2] functions as a soft segment. Among these, the acrylic block copolymer (Y) is more preferably an acrylic triblock copolymer represented by the above formula (Y2).

[0089] Specific examples of the methacrylic acid alkyl ester monomer constituting the monomer unit of the polymer block [A2] in the acrylic block copolymer (Y) include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, and 2-hexyldecyl methacrylate. Among these, methyl methacrylate is preferred from the viewpoints of high load-holding strength and dismantling properties. The polymer block [A2] may contain one type of methacrylic acid alkyl ester monomer as a monomer unit, or may contain two or more types of methacrylic acid alkyl ester monomers as monomer units.

[0090] Specific examples of the alkyl acrylate monomer constituting the monomer unit of the polymer block [B2] in the acrylic block copolymer (Y) include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate. From the viewpoint of achieving both high adhesive strength and good removability, the polymer block [B2] is preferably selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, and copolymers thereof. The polymer block [B2] may contain one type of alkyl acrylate monomer as a monomer unit, or may contain two or more types of alkyl acrylate monomer as monomer units.

[0091] The proportion of the polymer block [A2] in the acrylic block copolymer (Y) is preferably within the range of 2% to 16% by mass, more preferably within the range of 5% to 14% by mass, and even more preferably within the range of 8% to 12% by mass. When the proportion of the polymer block [A2] in the acrylic block copolymer (Y) is within the above range, the acrylic block copolymer (Y) exhibits excellent high-load holding power, drop impact resistance, and removability from a mat surface when blended with the acrylic block copolymer (X) within a predetermined range. When two or more types of polymer blocks [A2] are contained in one acrylic block copolymer (Y), the proportion of the polymer block [A2] in the acrylic block copolymer (Y) refers to the proportion of the total mass of the polymer blocks [A2] in the mass of the acrylic block copolymer (Y).

[0092] The proportion of the polymer block [B2] in the acrylic block copolymer (Y) is preferably within the range of 84% to 98% by mass, more preferably within the range of 86% to 95% by mass, and even more preferably within the range of 88% to 92% by mass. When the proportion of the polymer block [B2] in the acrylic block copolymer (Y) is within the above range, the acrylic block copolymer (Y) exhibits excellent high-load holding power, drop impact resistance, and removability from a mat surface when blended with the acrylic block copolymer (X) within a predetermined range. When two or more types of polymer blocks [B2] are contained in one acrylic block copolymer (Y), the proportion of the polymer block [B2] in the acrylic block copolymer (Y) refers to the proportion of the total mass of the polymer blocks [B2] in the mass of the acrylic block copolymer (Y).

[0093] The glass transition temperature of the polymer block [A2] is not particularly limited, but is preferably from 20° C. to 150° C., more preferably from 30° C. to 140° C., and even more preferably from 40° C. to 130° C. By setting the glass transition temperature of the polymer block [A2] within the above range, it is possible to achieve excellent high load holding power due to high cohesive strength, and excellent removability and dismantlability when the pressure-sensitive adhesive tape is stretched and peeled off.

[0094] The glass transition temperature of the polymer block [B2] is not particularly limited, but is preferably −80° C. to 40° C., more preferably −70° C. to 30° C., and even more preferably −60° C. to 20° C. By setting the glass transition temperature of the polymer block [B2] within the above range, excellent impact resistance can be achieved.

[0095] The glass transition temperatures of the polymer blocks [A2] and [B2] constituting the acrylic block copolymer (Y) can be determined in the same manner as the glass transition temperatures of the polymer blocks [A1] and [B1] constituting the acrylic block copolymer (X) described above.

[0096] The acrylic block copolymer (Y) may be modified, if necessary, in the molecular side chain or at the molecular main chain terminal with a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, or a trimethoxysilyl group, as long as the effects of the present invention are not impaired.

[0097] More specifically, preferred examples of the diblock acrylic block copolymer (Y) include acrylic diblock copolymers having a repeating unit represented by the following general formula (5).

[0098] [ka]

[0099] (In the above general formula (5), D and E each independently represent a repeating unit, D represents a methacrylic acid alkyl ester monomer unit, E represents an acrylic acid alkyl ester monomer unit, and s and t each independently represent the degree of polymerization of each monomer unit. In the above general formula (5), * represents a bond to another atom.)

[0100] D in the general formula (5) constitutes the polymer block [A2] in the diblock acrylic block copolymer (Y). That is, "-(D)" in the general formula (5) constitutes the polymer block [A2] in the diblock acrylic block copolymer (Y). SThe polymer block of the "-" portion corresponds to the polymer block [A2] in the diblock acrylic block copolymer (Y). Furthermore, E in the general formula (5) constitutes the polymer block [B2] in the diblock acrylic block copolymer (Y). That is, "-(E)" in the general formula (5) t The polymer block in the "-" portion corresponds to the polymer block [B2] in the diblock acrylic block copolymer (Y).

[0101] The methacrylic acid alkyl ester monomer unit in D in the general formula (5) can have the same form as the methacrylic acid alkyl ester monomer units in A and C in the general formula (1) described above.

[0102] The acrylic acid alkyl ester monomer unit in E in the general formula (5) can be the same as the acrylic acid alkyl ester monomer unit in B in the general formula (1) described above. E in the general formula (5) may contain one type of methacrylic acid alkyl ester monomer as a monomer unit, or may contain two or more types of methacrylic acid alkyl ester monomers as monomer units.

[0103] The diblock acrylic block copolymer (Y) preferably has a repeating unit represented by the following general formula (6).

[0104] [ka]

[0105] (In the above general formula (6), R 6 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituted by a substituent R 8 and the substituent R 8 represents a halogen atom, an amino group, or a cyano group; R 7 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituted by a substituent R 9and the substituent R 9 represents a halogen atom, an amino group, or a cyano group, and s and t each independently represent the degree of polymerization of each monomer unit.

[0106] In the above general formula (6), R 6 is R in the above general formula (2). 1 In the above general formula (6), R 7 is R in the above general formula (3). 3 In the general formula (6), s and t can have the same configuration as p and q in the general formula (1).

[0107] In the general formulas (5) and (6), s and t each independently represent the degree of polymerization of each monomer unit. The values ​​of s and t are related to the molecular weight, etc. s / (s+t) is preferably 0.02 to 0.20, more preferably 0.10 to 0.16. t / (s+t) is preferably 0.80 to 0.98, more preferably 0.84 to 0.90. By setting s / (s+t) and t / (s+t) within the above ranges, it becomes possible to adjust the storage modulus and other physical properties of the diblock acrylic block copolymer (Y) within predetermined ranges.

[0108] The diblock copolymer that can be the acrylic block copolymer (Y) is not particularly limited as long as it can have the physical properties of the acrylic block copolymer (Y) described above. Preferred forms of the diblock copolymer include polymethyl methacrylate block-polyn-butyl acrylate block, polyethyl methacrylate block-polyn-butyl acrylate block, polypropyl methacrylate block-polyn-butyl acrylate block, polymethyl methacrylate block-polyt-butyl acrylate block, and polymethyl methacrylate block-polypropyl acrylate block.

[0109] More specifically, preferred examples of the triblock acrylic block copolymer (Y) include acrylic triblock copolymers having a repeating unit represented by the following general formula (7).

[0110] [ka]

[0111] (In the above general formula (7), F, G, and H each independently represent a repeating unit, F and H each independently represent a methacrylic acid alkyl ester monomer unit, G represents an acrylic acid alkyl ester monomer unit, u, v, and w each independently represent the degree of polymerization of each monomer unit, and F and H may be methacrylic acid alkyl ester monomer units having the same chemical structure or may be methacrylic acid alkyl ester monomer units having different chemical structures. In the above general formula (7), * is a bond representing a bond to another atom.)

[0112] In the general formula (7), F and H represent repeating units different from G, and represent methacrylic acid alkyl ester monomer units. F and H in the general formula (7) constitute the polymer block [A2] in the acrylic block copolymer (Y). That is, "-(F)" in the general formula (1) u The polymer block of the "-" part and the "-(H) w The polymer blocks in the "-" portion correspond to the polymer block [A2] in the acrylic block copolymer (Y).

[0113] In the general formula (7), F and H are each independent and may be methacrylic acid alkyl ester monomer units having the same chemical structure or different chemical structures. That is, the polymer block [A2] in the acrylic block copolymer (Y) may contain a polymer block of one type of structure or may contain polymer blocks of two or more different structures.

[0114] Details of F and H in the general formula (7) can be the same as the details of A and C in the general formula (1) described above. The methacrylic acid alkyl ester monomer unit in F and H in the general formula (7) is preferably represented by the general formula (2) described above.

[0115] In the general formula (7), G represents a repeating unit different from F and H, and represents an acrylic acid alkyl ester monomer unit. G in the general formula (7) constitutes the polymer block [B2] in the acrylic block copolymer (Y). That is, "-(G)" in the general formula (7) v The polymer block in the "-" portion corresponds to the polymer block [B2] in the acrylic block copolymer (Y).

[0116] Details of G in general formula (7) can be the same as the details of B in general formula (1) above. In addition, the acrylate alkyl ester monomer unit in G in general formula (7) is preferably represented by the above general formula (3).

[0117] In the general formula (7), u, v, and w each independently represent the degree of polymerization of each monomer unit. The values ​​of u, v, and w are related to the molecular weight, etc. u / (u+v+w) is preferably 0.01 to 0.10, more preferably 0.05 to 0.08. v / (u+v+w) is preferably 0.79 to 0.98, more preferably 0.84 to 0.90. w / (u+v+w) is preferably 0.01 to 0.10, more preferably 0.05 to 0.08. By setting u, v, and w within the above ranges, it becomes possible to adjust the storage modulus and other physical properties of the acrylic triblock copolymer, which is the acrylic block copolymer (Y), within predetermined ranges.

[0118] In general formula (7), F and H may be the same repeating unit or different repeating units, but it is preferable that F and H in general formula (7) are the same repeating unit, as this makes it easier to adjust the storage modulus and the like to a desired range. In other words, it is preferable that the triblock acrylic block copolymer (Y) is represented by the above formula (Y2), and that the two [A2] in formula (Y2) have the same structure.

[0119] Specifically, when the triblock acrylic block copolymer (Y) has a repeating unit represented by the general formula (8) described later, R 11 and R 15 and are preferably the same group, u / (u+v+w) is 0.01 to 0.20, v / (u+v+w) is 0.60 to 0.98, and w / (u+v+w) is 0.01 to 0.20. By setting u / (u+v+w), v / (u+v+w), and w / (u+v+w) within the above ranges, it is possible to adjust the storage modulus and other physical properties of the triblock acrylic block copolymer (Y) within predetermined ranges.

[0120] The triblock acrylic block copolymer (Y) preferably has a repeating unit represented by the following general formula (8).

[0121] [ka]

[0122] (In the above general formula (8), R 11 and R 15 are each independently R in the general formula (4). 1 and R 5 is defined similarly to R 13 is R in the above general formula (4) 3 where u, v, and w each independently represent the degree of polymerization of each monomer unit.

[0123] In the above general formula (8), R 11is R in the above general formula (2). 1 In the above general formula (8), R 13 is R in the above general formula (3). 3 In the above general formula (8), R 15 is R in the above general formula (2). 1 The same aspects as above can be applied.

[0124] In addition, in the general formula (8), u, v, and w can be applied in the same manner as u, v, and w in the general formula (7). 11 and R 15 may be the same or different.

[0125] In the above general formula (8), R 11 is preferably selected from the group consisting of linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and t-butyl groups, and cyclobutyl groups. 13 is preferably selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, hexyl, octyl, nonyl, decyl, or undecyl groups. 15 is preferably selected from the group consisting of a linear or branched alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and the like, and a cyclobutyl group. 11 , R 13 , R 15 are each selected from the above functional group group, it is preferable that u / (u+v+w) is 0.01 to 0.20, v / (u+v+w) is 0.60 to 0.98, and w / (u+v+w) is 0.01 to 0.20.

[0126] When F and H in the general formula (7) are different repeating units, the "-(F)" contained in the molecule of the triblock acrylic block copolymer (Y) u- Total weight of polymer blocks of the "-" part (the "-(F) u The total weight of the polymer blocks of "-" part is referred to as a2. q - Total weight of polymer blocks of the "-" part (the "-(G) v The total weight of the polymer blocks of - is referred to as b2. From the viewpoint of adhesive properties, the mass ratio of a2 / b2 is preferably within the range of 1 / 98 to 8 / 84, and more preferably within the range of 4 / 92 to 6 / 88.

[0127] When F and H in the general formula (7) are different repeating units, the "-(H)" contained in the molecule of the triblock acrylic block copolymer (Y) w Total weight of polymer blocks of "-" part (the "-(H)" w The total weight of the polymer blocks of "-" parts is referred to as c2. v From the viewpoint of adhesive properties, the ratio of the "-" portion to the total weight of the polymer blocks is preferably in the range of 1 / 98 to 8 / 84, more preferably 4 / 92 to 6 / 88, in terms of the mass ratio c2 / b2.

[0128] When F and H in the general formula (7) are the same repeating unit, the "-(F)" contained in the molecule of the triblock copolymer (Y) u The polymer block of the - part and the -(H) w - Total weight of polymer blocks (F) u The polymer block of the - part and the -(H) w The total weight of the polymer blocks of "-" parts is referred to as d2.) and "-(G) v The ratio (d2 / b2) of the - portion to the total weight of the polymer blocks (referred to as b2) can be the same as the weight ratio calculated from the weights of the polymer block [A2] and the polymer block [B2] in the above-mentioned acrylic block copolymer (Y). Specifically, the mass ratio of d2 / b2 can be within the range of 2 / 98 to 16 / 84, preferably within the range of 5 / 95 to 14 / 86, and more preferably within the range of 8 / 92 to 12 / 88. In addition, when F and H in the general formula (7) are the same repeating unit, "-(F) u The total weight of the polymer blocks in the - and -(H) w The sum of the weight of the "-" portion and the total weight of the polymer blocks is the weight of the polymer block [A2] in the acrylic block copolymer (Y).

[0129] The triblock copolymer that can be the acrylic block copolymer (Y) is not particularly limited as long as it can have the physical properties of the acrylic block copolymer (Y), but preferred forms of the triblock copolymer include polymethyl methacrylate block-polyn-butyl acrylate block-polymethyl methacrylate, polyethyl methacrylate block-polyn-butyl acrylate block-polyethyl methacrylate, polypropyl methacrylate block-polyn-butyl acrylate block-polypropyl methacrylate, polymethyl methacrylate block-polyt-butyl acrylate block-polymethyl methacrylate, polymethyl methacrylate block-polypropyl acrylate block-polymethyl methacrylate, etc. Among these, polymethyl methacrylate block-polyn-butyl acrylate block-polymethyl methacrylate is preferred.

[0130] (others) The acrylic block copolymer constituting the adhesive resin may contain only one or more acrylic block copolymers (X) having a storage modulus within the specified range and one or more acrylic block copolymers (Y) having a storage modulus within the specified range, or may contain an optional acrylic block copolymer (Z) in addition to the acrylic block copolymers (X) and (Y). When the acrylic block copolymer contains the acrylic block copolymers (X), (Y), and (Z), the total content of the acrylic block copolymers (X) and (Y) in the total amount of the acrylic block copolymers may be an amount that does not inhibit the effects of containing the acrylic block copolymers (X) and (Y).

[0131] <2> tackifying resin The pressure-sensitive adhesive composition in this embodiment may contain one or more tackifying resins in addition to the pressure-sensitive adhesive resins containing the acrylic block copolymer (X) and acrylic block copolymer (Y). In other words, the pressure-sensitive adhesive layer in this embodiment may further contain one or more tackifying resins. When the pressure-sensitive adhesive layer contains a tackifying resin, a pressure-sensitive adhesive tape with even more excellent adhesive strength can be achieved.

[0132] The tackifier resin preferably has a softening point of 95° C. or higher. More preferably, the softening point is 95° C. to 180° C., and more preferably 95° C. to 140° C., in order to form a pressure-sensitive adhesive layer with high adhesive performance. When a (meth)acrylate tackifier resin is used, the glass transition temperature is preferably 30° C. to 200° C., and more preferably 50° C. to 160° C.

[0133] As the tackifier resin, a tackifier resin having a softening point (softening temperature) of 95°C or higher can be preferably used. A pressure-sensitive adhesive layer containing a tackifier resin having a softening point equal to or higher than the above-mentioned lower limit can realize a pressure-sensitive adhesive tape with superior adhesive strength. Among the tackifier resins exemplified above, terpene-based tackifier resins (e.g., terpene-modified phenolic resins) and rosin-based tackifier resins (e.g., esterified products of polymerized rosin) having the above softening points can be preferably used. The upper limit of the softening point of the tackifier resin is not particularly limited, and can be, for example, approximately 200°C or lower. The softening point of the tackifier resin is defined here as a value measured by the softening point test method (ring and ball method) specified in either JIS K 5902 or JIS K 2207.

[0134] The amount of the tackifier resin used is not particularly limited and can be appropriately selected depending on the purpose. In this embodiment, the tackifier resin is preferably contained in an amount of 10 to 75 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, per 100 parts by mass of the total amount of adhesive resins. When the content of the tackifier resin in the adhesive layer is within the above range, adhesion to the adherend can be easily ensured.

[0135] Specific examples of the tackifier resin include rosin-based tackifier resins, polymerized rosin-based tackifier resins, polymerized rosin ester-based tackifier resins, rosin phenol-based tackifier resins, stabilized rosin ester-based tackifier resins, disproportionated rosin ester-based tackifier resins, hydrogenated rosin ester-based tackifier resins, terpene-based tackifier resins, terpene phenol-based tackifier resins, petroleum resin-based tackifier resins, and (meth)acrylate-based tackifier resins. These may be used alone or in combination of two or more. Among these, preferred tackifier resins are polymerized rosin ester-based tackifier resins, rosin phenol-based tackifier resins, disproportionated rosin ester-based tackifier resins, hydrogenated rosin ester-based tackifier resins, terpene phenol-based resins, and (meth)acrylate-based resins.

[0136] <3> Crosslinking agent The pressure-sensitive adhesive composition of the present embodiment may contain a crosslinking agent to further improve the cohesive strength of the pressure-sensitive adhesive layer. The crosslinking agent is not particularly limited and can be appropriately selected depending on the purpose. Examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, and aziridine-based crosslinking agents. These may be used alone or in combination of two or more. Among these, crosslinking agents that are mixed with the acrylic polymer after production to promote a crosslinking reaction are preferred, and it is more preferred to use isocyanate-based crosslinking agents and epoxy-based crosslinking agents that are highly reactive with the acrylic polymer.

[0137] Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, triphenylmethane isocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and trimethylolpropane-modified tolylene diisocyanate. These may be used alone or in combination of two or more. Among these, trifunctional polyisocyanate-based compounds such as tolylene diisocyanate and its trimethylolpropane adduct, and triphenylmethane isocyanate are particularly preferred.

[0138] <4> Filler The pressure-sensitive adhesive composition in this embodiment essentially contains at least a pressure-sensitive adhesive resin containing the above-mentioned acrylic block copolymer (X) and acrylic block copolymer (Y), and preferably further contains one or more fillers. In other words, in this embodiment, the pressure-sensitive adhesive layer may further contain one or more fillers. By containing a filler, the filler is exposed from the pressure-sensitive adhesive layer when the pressure-sensitive adhesive tape is stretched, thereby reducing the adhesive area between the pressure-sensitive adhesive layer and the adherend. This makes it possible to more easily and quickly peel off the pressure-sensitive adhesive tape even when the pressure-sensitive adhesive tape is stretched at a relatively large angle, for example, perpendicular (90°), to the application surface of the adherend (hereinafter sometimes referred to as the "adhesion surface"), or even when the pressure-sensitive adhesive tape is stretched at a high speed.

[0139] The type of the filler is not particularly limited and can be appropriately selected within a range that does not impair the effects of the present invention, and may be an inorganic filler or an organic filler. These may be used alone or in combination of two or more types.

[0140] Specific examples of the organic filler material include acrylic resins such as polymethyl methacrylate, polyolefin resins such as polyethylene resin and polypropylene resin, polyester resin, polystyrene resin, phenolic resin, polyurethane resin, polyamide resins such as nylon, polyimide resin, benzoguanamine resin, urea-formalin resin, styrene / methacrylic acid copolymer, fluororesin, polycarbonate resin, polyvinylidene chloride resin, epoxy resin, etc. Further examples of the organic filler include thermosetting resin-based hollow fillers.

[0141] Specific examples of the inorganic filler material include aluminum hydroxide, magnesium hydroxide, aluminum oxide, silicon oxide, magnesium oxide, zinc oxide, titanium oxide, zirconium oxide, iron oxide, silicon carbide, boron nitride, aluminum nitride, titanium nitride, silicon nitride, titanium boride, carbon, nickel, copper, aluminum, titanium, gold, silver, zirconium hydroxide, basic magnesium carbonate, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, tin oxide, tin oxide hydrate, borax, zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium-calcium carbonate, calcium carbonate, barium carbonate, acid Examples of suitable inorganic materials include molybdenum oxide, antimony oxide, red phosphorus, mica, clay, kaolin, talc, zeolite, wollastonite, smectite, silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, ultrafine amorphous silica, etc.), silicone, potassium titanate, magnesium sulfate, sepiolite, zonolite, aluminum borate, barium sulfate, barium titanate, zirconia oxide, cerium, tin, indium, carbon, sulfur, thorium, cobalt, molybdenum, strontium, chromium, barium, lead, tin oxide, indium oxide, diamond, magnesium, platinum, zinc, manganese, and stainless steel. Silicone is an inorganic polymer with an inorganic-organic hybrid structure, with the inorganic component siloxane bond as the main chain and side chains connected by organic groups such as alkyl chains. Among these, fillers such as silicone, aluminum hydroxide, and nickel are preferred, and silicone (silicone-based filler) is even more preferred because it can highly effectively exhibit the stretch-release properties due to the inclusion of the above-mentioned filler and can further increase the impact resistance of the tape.

[0142] The inorganic filler may be surface-treated, such as by silane coupling treatment or stearic acid treatment, in order to improve dispersibility in the pressure-sensitive adhesive composition.

[0143] Among the above inorganic fillers, silicone-based fillers include, specifically, silicone rubber particles obtained by three-dimensionally crosslinking linear organopolysiloxanes (see JP-A-63-77942, JP-A-3-93834, and JP-A-04-198324), powdered silicone rubber (see U.S. Pat. No. 3,843,601, JP-A-62-270660, and JP-A-59-96122), etc. Furthermore, silicone composite particles (see JP-A-7-196815) can also be used, in which the surfaces of the silicone rubber particles obtained by the above method are coated with a silicone resin that is a cured product of polyorganosilsesquioxane having a three-dimensional network-like crosslinked structure represented by (R'SiO3 / 2)n (R' represents a substituted or unsubstituted monovalent hydrocarbon group).

[0144] Examples of such silicone particles that can be used include Trefil E-500, Trefil E-600, Trefil E-601, and Trefil E-850, which are commercially available under the above-mentioned trade names from Dow Corning Toray Silicone Co., Ltd., and KMP-600, KMP-601, KMP-602, and KMP-605, which are commercially available from Shin-Etsu Chemical Co., Ltd.

[0145] Another example of a silicone-based filler that can be used is acrylic-modified silicone particles. Examples of the acrylic-modified silicone particles include emulsion graft polymers of polyorganosiloxane represented by the following general formula (9), an acrylic acid ester monomer and / or a methacrylic acid ester monomer, and a functional group-containing monomer copolymerizable therewith.

[0146] [ka]

[0147] (In the above general formula (9), R 1 and R 2 each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X 1 , X 2 , X3 , X 4 , X 5 , and X 6 each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a hydroxyl group; Y 1 and Y 2 are each independently, X 1 or -[O-Si(X 7 )(X 8 )] c -X 9 and X represents a group represented by 7 , X 8 , and X 9 each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a hydroxyl group; X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 and Y 1 and Y 2 at least two groups in the formula (I) are hydroxyl groups, and a, b, and c are each independently a positive number satisfying 0≦a≦1,000, 100≦b≦10,000, and 1≦c≦1,000.

[0148] Examples of the acrylic acid ester monomer or methacrylic acid ester monomer include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and cyclohexyl methacrylate.

[0149] Examples of functional group-containing monomers copolymerizable with the above-mentioned acrylic acid ester monomers and / or methacrylic acid ester monomers include monomers having unsaturated bonds such as carboxyl groups, amide groups, hydroxyl groups, vinyl groups, and allyl groups.

[0150] The acrylic-modified silicone particles are preferably obtained by emulsion graft polymerization of 100 parts by mass of polyorganosiloxane represented by general formula (9) with 10 to 100 parts by mass of an acrylic acid ester monomer and / or a methacrylic acid ester monomer and 0.01 to 20 parts by mass of a functional group-containing monomer copolymerizable therewith. The conditions for emulsion graft polymerization are not particularly limited, and known radical initiators typically used for acrylic polymers can be used as the initiator during polymerization. Known anionic surfactants or nonionic surfactants can also be used as the emulsifier.

[0151] The acrylic-modified silicone particles can be granulated and powdered by spray drying, airflow drying, or the like. Among these, a spray dryer is preferred from the viewpoint of productivity. Hot drying is preferred for powdering, and treatment is preferably carried out at 80 to 150°C. In addition, commercially available products such as Chaline R-170S and Chaline R-200 (both manufactured by Nissin Chemical Industry Co., Ltd.) can also be used as the acrylic-modified silicone particles.

[0152] The shape of the filler is not particularly limited and can be appropriately selected depending on the purpose, and may be regular or irregular. Specific examples of the filler shape include polygonal, cubic, elliptical, spherical, needle-like, plate-like, and scale-like shapes. Fillers of these shapes may be used alone or in combination of two or more. Furthermore, fillers of these shapes may be aggregated. Among these, elliptical, spherical, and polygonal shapes are preferred as the shape of the filler, with spherical shapes being more preferred. This is because, when the pressure-sensitive adhesive tape is stretched, the adhesive layer slides well on the adherend, allowing the pressure-sensitive adhesive tape to be peeled off more easily and quickly.

[0153] The particle size distribution (D90 / D10) of the filler is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 2.5 to 20, and from the viewpoint of impact resistance, is more preferably 2.5 to 15, and even more preferably 2.5 to 5. When the particle size distribution (D90 / D10) of the filler is within the preferred range, the adhesive tape can be peeled more easily and quickly, is less likely to tear even when the adhesive tape substrate is thin, and has excellent impact resistance, shear adhesive strength, and split adhesive strength. On the other hand, when the particle size distribution (D90 / D10) of the filler is less than 2.5, stretch releasability may be impaired, and when it exceeds 20, adhesive properties such as impact resistance, shear adhesive strength, and split adhesive strength may be impaired.

[0154] The particle size distribution (D90 / D10) of the filler can be obtained by measuring the average particle size of the filler using, for example, a measuring device (Microtrac) that uses a laser diffraction scattering method and converting it into a particle size distribution.

[0155] The average particle size of the filler is 0.1 to 40 μm, preferably 1 to 40 μm, more preferably 3 to 35 μm, even more preferably 5 to 30 μm, and particularly preferably 10 to 25 μm. When the average particle size of the filler is within the preferred range, the adhesive tape can be peeled off more easily and quickly, is less likely to tear even when the adhesive tape base is thin, and has excellent impact resistance, shear adhesive strength, and split adhesive strength. On the other hand, if the filler particle size is less than 0.1 μm, stretch releasability may be impaired, and if it exceeds 40 μm, adhesive performance such as impact resistance, shear adhesive strength, and split adhesive strength may be impaired.

[0156] The average particle size of the filler refers to the volume average particle size, and can be measured, for example, by using a measuring device (Microtrac) that uses a laser diffraction scattering method.

[0157] In the present embodiment, the ratio of the average particle size of the filler to the average thickness of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose. However, the ratio of the average particle size of the filler to the average thickness of the adhesive layer, expressed as [volume average particle size of the filler / average thickness of the adhesive layer], is preferably 5 / 100 or more, more preferably 5 / 100 to 95 / 100, even more preferably 10 / 100 to 75 / 100, and particularly preferably 20 / 100 to 60 / 100. A ratio of 5 / 100 or more allows for easier and faster peeling of the adhesive tape, and is less likely to tear even when the adhesive tape substrate is thin. Furthermore, a ratio of 95 / 100 or less is advantageous in that it provides better adhesive properties such as impact resistance, shear adhesive strength, and split adhesive strength.

[0158] The content of the filler in the pressure-sensitive adhesive layer of this embodiment is preferably 0 to 300 parts by mass, more preferably 1 to 100 parts by mass, preferably 10 to 60 parts by mass, and even more preferably 20 to 50 parts by mass, relative to 100 parts by mass of the adhesive resin. When the filler content is 1% by mass or more relative to 100 parts by mass of the adhesive resin, the adhesive tape can be more easily and quickly peeled off. Furthermore, when the filler content is 100 parts by mass or less relative to 100 parts by mass of the adhesive resin, it is possible to prevent the pressure-sensitive adhesive composition from remaining on the adherend, deterioration in impact resistance, and weakening of shear adhesive strength and split adhesive strength. The content of the filler in the pressure-sensitive adhesive layer of the present embodiment can be adjusted appropriately when preparing the pressure-sensitive adhesive composition, which is a precursor of the pressure-sensitive adhesive layer.

[0159] The volume ratio of the filler to the entire volume of the pressure-sensitive adhesive layer in this embodiment is not particularly limited, as long as the inclusion of the filler does not impair the high-load holding power or impact resistance of the pressure-sensitive adhesive tape, and does not reduce the adhesive strength or removability. For example, it can be in the range of 11 to 44 volume%, preferably 13 to 42 volume%, more preferably 15 to 40 volume%, and even more preferably 17 to 38 volume%. When the volume ratio of the filler is equal to or greater than the predetermined value, the pressure-sensitive adhesive tape can be more easily and quickly peeled off. Furthermore, when the volume ratio of the filler is equal to or less than the predetermined value, it is possible to prevent the pressure-sensitive adhesive layer from remaining on the adherend, deterioration in impact resistance, and weakening of shear adhesive strength and split adhesive strength.

[0160] The volume ratio of the filler to the volume of the entire adhesive layer can be calculated using the following formula. The density of each material is a value measured in accordance with JIS Z 8804. The volume ratio of the filler to the volume of the entire adhesive layer is, in other words, the volume ratio of the filler to the volume of the adhesive that forms the adhesive layer. When two or more types of adhesive resins are included, the volume of each adhesive resin (volume A1 of adhesive resin A1, volume A2 of adhesive resin A2, etc.) is calculated using the following formula (1), and their sum is taken as the volume A of the entire adhesive resin. Mass of adhesive resin A (g) / Density of adhesive resin A (g / cm 3 ) = Volume A of adhesive resin (cm 3 ) Formula (1) Filler mass B (g) / Filler density B (g / cm 3 ) = Filler volume B (cm 3 ) Formula (2) Filler volume B (cm 3 ) / (volume A of adhesive resin (cm 3 ) + filler volume B (cm 3 )) × 100 = Filler volume ratio (%) Formula (3) Furthermore, when the PSA layer and the PSA forming it contain a component C other than the adhesive resin and filler, the volume of the other components is also calculated from the weight and density, and the volume of the filler B is divided by the sum of the volume A of the adhesive resin, the volume B of the filler, and the volume C of the other components, to calculate the volume ratio of the filler. Specifically, when the PSA layer and the PSA forming it contain a tackifier resin, in addition to the volume A of the adhesive resin and the volume B of the filler, the volume C of the tackifier resin is calculated using the following formula (4), and the volume ratio of the filler (%) can be calculated using the following formula (5). Mass of tackifying resin C (g) / Density of tackifying resin C (g / cm 3 ) = Volume of tackifying resin C (cm 3 ) Formula (4) Filler volume B (cm 3 ) / (volume A of adhesive resin (cm 3 ) + filler volume B (cm 3 ) + volume of tackifying resin C (cm 3 )) × 100 = Filler volume ratio (%) Formula (5)

[0161] <5> Other ingredients In this embodiment, the pressure-sensitive adhesive layer may optionally contain other components in addition to the above-described adhesive resin and filler. The other components are not particularly limited and can be appropriately selected within a range that does not impair the properties of the pressure-sensitive adhesive tape. Examples include polymer components other than the adhesive resin, crosslinking agents, antioxidants, UV absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, antifoaming agents, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, plasticizers, softeners, flame retardants, and metal deactivators. These may be used alone or in combination of two or more. The content of the other components in the pressure-sensitive adhesive layer may be appropriately selected within a range that does not impair the properties of the pressure-sensitive adhesive tape.

[0162] (2) Physical properties In this embodiment, the storage modulus G'(23°C) of the pressure-sensitive adhesive layer at 23°C is preferably in the range of 0.01 MPa to 100.0 MPa, more preferably in the range of 0.05 MPa to 10.0 MPa, and even more preferably in the range of 0.10 MPa to 10.0 MPa. This is because when the storage modulus of the pressure-sensitive adhesive layer is in the above range, the pressure-sensitive adhesive layer exhibits excellent high load holding power, drop impact resistance, and removability from a matte surface.

[0163] The storage modulus G'(23°C) of the adhesive layer at 23°C was measured by stacking the adhesive layers to a thickness of 2 mm to form a test piece, attaching parallel plates with a diameter of 7.9 mm to a viscoelasticity tester, Ares 2kSTD, manufactured by Rheometrics, and sandwiching the test piece between them at a temperature of 23°C and a frequency of 1 Hz.

[0164] The pressure-sensitive adhesive layer preferably has a stress at 25% elongation of 0.04 to 0.4 MPa, more preferably 0.05 to 0.1 MPa. When the stress at 25% elongation of the pressure-sensitive adhesive layer is within this preferred range, the pressure-sensitive adhesive tape can have a suitable adhesive strength, and can be relatively easily peeled off even during stretch-peeling. Furthermore, when the stress at 25% elongation of the pressure-sensitive adhesive layer is 0.04 MPa or more, the pressure-sensitive adhesive tape is unlikely to peel off even when a load is applied in the shear direction of the pressure-sensitive adhesive tape while fixing hard adherends together, and when the stress is 0.4 MPa or less, the force required to stretch the pressure-sensitive adhesive tape when peeling it off is not excessive.

[0165] The stress of the pressure-sensitive adhesive layer at 25% elongation refers to the stress value measured when the pressure-sensitive adhesive layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the longitudinal direction at a tensile speed of 300 mm / min using a Tensilon tensile tester (model: RTF1210, manufactured by A&D Co., Ltd.) under measurement atmosphere conditions of 23°C and 50% RH, and elongated by 25%.

[0166] The pressure-sensitive adhesive layer preferably has a breaking strength of 0.5 to 2.1 MPa, more preferably 1.0 to 2.1 MPa. When the breaking strength of the pressure-sensitive adhesive layer is within the above-mentioned preferred range, tearing of the pressure-sensitive adhesive tape can be prevented even when the pressure-sensitive adhesive tape is stretched and peeled off, and the load required to stretch the pressure-sensitive adhesive tape does not become excessive, facilitating re-peeling by peeling. Furthermore, when the breaking strength of the pressure-sensitive adhesive layer is 0.5 MPa or more, adhesive residue due to cohesive failure of the pressure-sensitive adhesive layer is unlikely to occur when the pressure-sensitive adhesive tape is stretched and peeled off, and when it is 2.1 MPa or less, sufficient adhesiveness can be obtained.

[0167] The breaking strength of the adhesive layer refers to the stress value measured when the adhesive layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the longitudinal direction at a tensile speed of 300 mm / min using a Tensilon tensile tester (model: RTF1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until breaking.

[0168] The pressure-sensitive adhesive layer preferably has a breaking elongation of 450 to 1300%, more preferably 500 to 1200%, and even more preferably 600 to 1100%. When the breaking elongation of the pressure-sensitive adhesive layer is within the above preferred range, it is possible to achieve both favorable adhesiveness and removability (ease of peeling).

[0169] The breaking elongation of the pressure-sensitive adhesive layer refers to the tensile elongation measured when the pressure-sensitive adhesive layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the longitudinal direction at a tensile speed of 300 mm / min using a Tensilon tensile tester (model: RTF1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until breaking.

[0170] The pressure-sensitive adhesive layer preferably has an average thickness of 5 μm to 150 μm, more preferably 10 μm to 120 μm, even more preferably 20 μm to 110 μm, and particularly preferably 30 μm to 100 μm. When the pressure-sensitive adhesive tape has pressure-sensitive adhesive layers on both sides, the "average thickness of the pressure-sensitive adhesive layer" refers to the average thickness of the pressure-sensitive adhesive layer on one side of the pressure-sensitive adhesive tape. When the pressure-sensitive adhesive tape has pressure-sensitive adhesive layers on both sides, the average thickness of the pressure-sensitive adhesive layer on one side and the average thickness of the pressure-sensitive adhesive layer on the other side may be the same or different, but are preferably the same average thickness.

[0171] The average thickness of the pressure-sensitive adhesive layer can be measured by the following method. Specifically, the pressure-sensitive adhesive tape is immersed in liquid nitrogen for 1 minute, and then the tape is folded and split in the liquid nitrogen using tweezers along the width direction of the tape to prepare a section for observing the split surface in the thickness direction of the pressure-sensitive adhesive tape. The section is returned to room temperature in a desiccator, and then fixed to a sample stage so that an electron beam is incident perpendicularly to the split surface. The split surface is observed using an electron microscope. The thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape is measured at 10 locations using the scale of the electron microscope, and the arithmetic mean value is taken as the average thickness of the pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer is the length measured from one surface to the other surface along the lamination direction.

[0172] 2.Base material layer In this embodiment, the base layer has the function of supporting the pressure-sensitive adhesive layer and imparting extensibility to the pressure-sensitive adhesive sheet. In this embodiment, the base layer has a breaking stress of 1 to 100 MPa and a breaking elongation of 300 to 3000%.

[0173] The substrate layer may have a single layer structure, or a multi-layer structure of two, three or more layers, so long as it has predetermined physical properties.

[0174] (1) Physical properties In the present embodiment, the base layer preferably has a breaking stress of 1 to 100 MPa. A breaking stress of 1 MPa or more allows the adhesive tape to be peeled from the adherend without tearing even when pulled. Furthermore, a breaking stress of 100 MPa or less can prevent the adhesive tape from being subjected to excessive stress when pulled. In particular, the breaking stress of the base layer is preferably 10 MPa or more, or more than 10 MPa and 90 MPa or less, more preferably 15 to 90 MPa, more preferably 30 to 90 MPa, and even more preferably 50 to 90 MPa. By setting the breaking stress of the base layer within the above range, the adhesive tape can be easily stretched without tearing not only in the horizontal direction but also in the vertical direction when stretching the adhesive tape from an adherend having a matte or smooth surface, and removability from the adherend can be further improved.

[0175] The breaking stress of the base material layer refers to the stress value measured when the base material layer was punched into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until breaking.

[0176] The breaking stress can be adjusted by selecting an appropriate material and by applying stretching during the manufacturing process of the base layer.

[0177] The base layer preferably has a breaking elongation of 300 to 3000%. A breaking elongation of 400% or more prevents excessive stress when peeling off the adhesive tape, even when the adhesive tape is firmly adhered to an adherend. Furthermore, a breaking elongation of 3000% or less prevents the adhesive tape from being stretched too far when peeling off, enabling work in a small space. A more preferred range of the breaking elongation of the base layer is 500 to 2500%, preferably 530 to 1700%, even more preferably 560 to 1300%, and even more preferably 600 to 1200%. Setting the breaking elongation within the above range can prevent excessive stress when the adhesive tape is stretched in the desired direction for peeling, thereby improving releasability by stretching.

[0178] The breaking elongation of the base material layer refers to the tensile elongation measured when the base material layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and broken.

[0179] The breaking elongation can be adjusted by appropriately selecting the material of the base layer and by applying stretching during the manufacturing process of the base layer.

[0180] The base layer preferably has a 50% modulus of 0.1 to 5 MPa. A 50% modulus of 0.1 MPa or more can suppress defects associated with deformation, such as slippage, when a load is applied to the adhesive tape or the adherend. Furthermore, a 50% modulus of 5 MPa or less allows an operator to pull the adhesive tape from the adherend with a relatively light force in the initial stage of peeling it off. A more preferred range for the 50% modulus of the base layer is 0.5 to 4.5 MPa, and even more preferably 1 to 4 MPa. By setting the 50% modulus of the base layer within the above range, the adhesive tape can be stretched and peeled off from the adherend without the need for excessive force in the initial stage.

[0181] The 50% modulus of the base material layer refers to the stress value measured when the base material layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and the elongation reaches 50%.

[0182] The 50% modulus can be adjusted by appropriately selecting the material and by applying stretching during the manufacturing process of the base layer.

[0183] The base layer preferably has a rubber hardness of 25 to 90A, more preferably 30 to 85A, and even more preferably 35 to 80A. A rubber hardness of 25A or more can prevent the adhesive tape from tearing when stretched and peeled off. Furthermore, a rubber hardness of 90A or less makes the base layer soft, and for example, when an adherend to which the adhesive tape is attached is dropped, the adhesive tape can more easily absorb the impact, thereby protecting the adherend from the impact. In other words, the impact resistance of the adhesive tape can be improved.

[0184] The rubber hardness of the base layer is Shore A hardness, and refers to a value measured in accordance with JIS K 6253 using a durometer (spring type rubber hardness tester) (model: GS-719G, manufactured by Teclock Corporation).

[0185] Furthermore, the rubber hardness can be adjusted by appropriately selecting the material, for example, by changing the molecular weight of the resin, or by changing the monomer unit if a styrene monomer unit is contained.

[0186] The base layer preferably has an average thickness of 10 to 500 μm. A thickness of 10 μm or more ensures the strength of the adhesive tape, while a thickness of 500 μm or less prevents the adhesive tape from becoming too thick and difficult to pull. In particular, the average thickness of the base layer is preferably 20 to 250 μm, and more preferably 30 to 200 μm. By keeping the average thickness of the base layer within the above range, it becomes possible to more effectively exhibit the releasability when stretched and the strength to withstand impact.

[0187] In this specification, the "thickness of the base layer" refers to the average value of the thickness measured at any five points in the base layer using a TH-104 paper / film thickness measuring instrument (manufactured by Tester Sangyo Co., Ltd.).

[0188] In the present embodiment, the thickness ratio between the pressure-sensitive adhesive layer and the base layer is not particularly limited and can be appropriately selected depending on the purpose. However, the ratio of the thickness of the pressure-sensitive adhesive layer to the thickness of the base layer, expressed as [thickness of pressure-sensitive adhesive layer / thickness of base layer], is preferably 1 / 6 to 6 / 1, more preferably 1 / 3 to 3 / 1, and even more preferably 1 / 2 to 2 / 1. When the thickness ratio of the pressure-sensitive adhesive layer to the thickness of the base layer is within the preferred range, the pressure-sensitive adhesive tape can achieve excellent adhesion and removability (ease of peeling). On the other hand, if the ratio is greater than 6 / 1, there is a possibility that only the pressure-sensitive adhesive layer will remain on the adherend during the removability step of the pressure-sensitive adhesive tape. Furthermore, if the ratio is less than 1 / 6, there is a concern that the pressure-sensitive adhesive layer will not be able to conform to the surface of the adherend if it has an uneven shape, resulting in a decrease in adhesive strength. Note that when pressure-sensitive adhesive layers are provided on both sides of the base layer, the "thickness of the pressure-sensitive adhesive layer" when calculating the thickness ratio between the pressure-sensitive adhesive layer and the base layer refers to the sum of the thicknesses of the pressure-sensitive adhesive layers provided on both sides of the base layer.

[0189] (2) Composition The substrate layer is not particularly limited as long as it has the above-mentioned properties, and is usually composed of a substrate composition containing a resin as a main component. That is, a resin layer such as a resin film or a resin sheet can be used as the substrate layer. The substrate layer may be composed only of a resin, or may contain any component other than the resin.

[0190] (resin) The resin constituting the substrate layer is not particularly limited as long as it has the above-mentioned properties, and examples thereof include styrene-based resins, polyurethane resins, polyolefin resins, polyester resins, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyether ether ketone, polyether sulfone, polyetherimide, polyimide, fluorine resins, nylon, acrylic resins, etc. These may be used alone or in combination of two or more, but it is preferable to use two or more.

[0191] Among these, styrene-based resins or polyurethane resins are preferred because they can easily obtain suitable breaking stress and breaking elongation, and styrene-based resins are more preferred.The styrene-based resins are resins that exhibit thermoplasticity, so they are excellent in formability such as extrusion molding and injection molding, and are easy to form into a substrate layer.In addition, styrene-based resins are particularly easy to obtain excellent breaking elongation among the group of resins generally called thermoplastic resins, and can be suitably used as a substrate for a pressure-sensitive adhesive sheet. For the reasons mentioned above, the base layer preferably contains a styrene resin or a polyurethane resin as the main component, and more preferably a styrene resin as the main component. The styrene resin and polyurethane resin are described in more detail below. The main component refers to the component with the highest content in the total mass (100% by mass) of the base layer, and typically accounts for 50% or more.

[0192] -Styrene-based resin- When the base layer contains a styrene resin as a main component, the proportion (mass %) of the styrene resin relative to the total resin components of the base layer is preferably 50 to 100 mass %, more preferably 60 to 100 mass %, even more preferably 65 to 100 mass %, and particularly preferably 70 to 100 mass %. When the proportion of the styrene resin is within the above preferred range, a base layer with excellent breaking elongation and breaking stress can be obtained.

[0193] The styrene-based resin may have a single structure, such as a linear structure, a branched structure, or a multi-branched structure, or may be a mixture of different structures. A styrene-based resin rich in linear structures can provide the substrate layer with excellent elongation at break. On the other hand, a branched or multi-branched structure in which styrene blocks are arranged at the molecular end can form a pseudo-crosslinked structure and provide excellent cohesive strength. Therefore, it is preferable to use a mixture of styrene-based resins according to the required mechanical properties.

[0194] The styrene-based resin preferably contains structural units represented by the following chemical formula (A) in an amount of 5 to 50% by mass, more preferably 5 to 40% by mass, even more preferably 10 to 30% by mass, and particularly preferably 15 to 25% by mass, relative to the total mass of the styrene-based resin. When the proportion of structural units represented by the following chemical formula (A) relative to the total mass of the styrene-based resin is within the above-mentioned preferred range, it becomes easier to achieve suitable ranges for elongation at break and stress at break. In addition, * in the following chemical formula (A) represents a bond to another atom, and this also applies to chemical formulas described below.

[0195] [ka]

[0196] The styrene-based resin is not particularly limited, but a vinyl aromatic block copolymer of an aromatic vinyl compound and a conjugated diene compound is preferred.Specific examples include styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer, styrene-isoprene-butadiene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene block copolymer, styrene-ethylene-propylene block copolymer, and hydrogenated products of these copolymers.These can be used alone or in combination of two or more.

[0197] Among these, it is particularly preferable to use a styrene-based resin in combination with a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer.

[0198] When a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer are used in combination as the styrene-based resin, the content of the styrene-isoprene copolymer relative to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is preferably 0 to 80 mass%, more preferably 0 to 70 mass%, even more preferably 0 to 50 mass%, and particularly preferably 0 to 30 mass%. When the content of the styrene-isoprene copolymer is within the above preferred range, it is possible to achieve both excellent thermal durability while maintaining excellent elongation at break and stress at break.

[0199] The styrene-isoprene copolymer preferably has a weight-average molecular weight, measured in terms of standard polystyrene using gel permeation chromatography (GPC), in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. When the weight-average molecular weight of the styrene-isoprene copolymer is within the above preferred range, it is possible to ensure flowability during heating and compatibility when diluted with a solvent, which is preferable because it allows for a substrate layer to be obtained that has good workability in the production process and thermal durability.

[0200] Here, the weight average molecular weight of the styrene-isoprene copolymer measured by GPC is a value converted into standard polystyrene using a GPC apparatus (SC-8020, manufactured by Tosoh Corporation), and the measurement conditions are as follows. -Measurement conditions- Sample concentration: 0.5% by mass (tetrahydrofuran solution) Sample injection volume: 100 μL Eluent: tetrahydrofuran · Flow rate: 1.0mL / min · Measurement temperature: 40℃ Column: TSKgel® GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation) The method for producing the styrene-isoprene copolymer, the styrene-isoprene-styrene copolymer, and the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. The block copolymer can be obtained by an anionic living polymerization method, and if necessary, a coupling agent is added and reacted.

[0201] Specifically, the method for producing a styrene-isoprene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods, such as a method in which a styrene block and an isoprene block are sequentially polymerized by an anionic living polymerization method.

[0202] The method for producing a styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. Examples include a method in which a styrene block and an isoprene block are sequentially polymerized by an anionic living polymerization method, and a method in which a block copolymer having a living active end is produced and then reacted with a coupling agent to produce a coupled block copolymer.

[0203] The method for producing the mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. For example, a method of mixing the styrene-isoprene copolymer produced by the above method with a styrene-isoprene-styrene copolymer can be mentioned. As a method for producing a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer, it is also possible to produce them as a mixture simultaneously in one polymerization step.

[0204] In a more specific embodiment, the anionic living polymerization method involves first polymerizing styrene monomer in a polymerization solvent using an anionic polymerization initiator to form a polystyrene block having a living active end. Second, polymerizing isoprene from the living active end of the polystyrene block to obtain a styrene-isoprene diblock copolymer having a living active end. Third, reacting a portion of the styrene-isoprene diblock copolymer having a living active end with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. Fourth, using a polymerization terminator, deactivating the living active end of the remaining styrene-isoprene diblock copolymer having a living active end to form a styrene-isoprene diblock copolymer. This styrene-isoprene diblock copolymer may also be used as the vinyl aromatic block copolymer.

[0205] Furthermore, the styrene-based resin is preferably a hydrogenated styrene-based block copolymer (sometimes referred to as a hydrogenated styrene-based block copolymer). Among these, a hydrogenated styrene-based block copolymer composed of a polymer block A mainly composed of styrene-based compound units and a polymer block B composed of a random copolymer of linear hydrogenated butadiene structural units and hydrogenated isoprene structural units having side chains is preferred. The random presence of linear structural units contributing to crystallinity and structural units having side chains contributing to extensibility within polymer block B makes it easier to achieve both improved extensibility and strength at break. Specific examples of such hydrogenated styrene-based block copolymers include styrene-ethylene / butylene-styrene block copolymer (SEBS) and styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS). The styrene-ethylene-ethylene / propylene-styrene block copolymer is a hydrogenated block copolymer formed from styrene-butadiene-isoprene-styrene. The styrene-ethylene-butylene-styrene block copolymer is a hydrogenated styrene-isoprene / butadiene-styrene block copolymer, and among these, a hydrogenated styrene-isoprene-butadiene-styrene block copolymer is particularly preferred.

[0206] -Polyurethane resin- When the base layer contains a polyurethane resin as a main component, the proportion (mass %) of the polyurethane resin relative to all resin components in the base layer material is preferably 50 to 100 mass %, more preferably 60 to 100 mass %, even more preferably 65 to 100 mass %, and particularly preferably 70 to 100 mass %. By keeping the proportion of the polyurethane resin within the above preferred range, a base layer with excellent breaking elongation and breaking stress can be obtained.

[0207] The polyurethane resin is not particularly limited and can be appropriately selected depending on the purpose, but preferably has a softening point of 45°C or higher, and more preferably has a softening point of 55°C or higher. The upper limit of the softening point is preferably 110°C or lower. In this specification, the "softening point" refers to a value measured in accordance with JIS K 2207 (ring and ball method) (hereinafter, the same measurement method is used for softening point).

[0208] As the polyurethane resin, a reaction product of polyol (b1-1) and polyisocyanate (b1-2) can be suitably used. Specific examples of the reaction product include ester-based polyurethanes and ether-based polyurethanes. These can be used alone or in combination of two or more.

[0209] The polyol (b1-1) is not particularly limited and can be appropriately selected depending on the purpose. Examples include polyester polyols, polyether polyols, polycarbonate polyols, and acrylic polyols. These may be used alone or in combination of two or more. Among these, polyester polyols and polyether polyols are preferred as the polyol (b1-1) because they can provide the mechanical properties of the substrate layer. When heat resistance is required in the substrate layer, it is preferred to use polyester polyols, and when water resistance and biodegradability are required, it is preferred to use polyether polyols.

[0210] Examples of the polyester polyol include polyesters obtained by an esterification reaction between a low-molecular-weight polyol and a polycarboxylic acid, polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymer polyesters thereof.

[0211] Examples of low-molecular-weight polyols that can be used to produce the polyester polyols include aliphatic alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3-butanediol, each of which has a weight-average molecular weight of approximately 60 to 280, and cyclohexanedimethanol.

[0212] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; and anhydrides or esters thereof.

[0213] Examples of the polyether polyol include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0214] As the polycarbonate polyol, for example, a product obtained by reacting a carbonate ester and / or phosgene with a low-molecular-weight polyol described below can be used.

[0215] Examples of the carbonate ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, and diphenyl carbonate.

[0216] Examples of low-molecular-weight polyols that can be used in the production of the polycarbonate polyols and that can react with carbonate esters and / or phosgene include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, Examples of suitable phenolic compounds include 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol A, bisphenol F, and 4,4'-biphenol.

[0217] The polyisocyanate (b1-2) is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, etc., and examples thereof include alicyclic polyisocyanates, etc. These may be used alone or in combination of two or more.

[0218] Examples of the alicyclic polyisocyanate include isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4-methylcyclohexane diisocyanate, 2,6-methylcyclohexane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, dimer acid diisocyanate, bicycloheptane triisocyanate, etc. These may be used alone or in combination of two or more.

[0219] The method for producing the polyurethane resin (b1) by reacting the polyol (b1-1) with the polyisocyanate (b1-2) is not particularly limited and can be appropriately selected from conventionally known production methods. For example, there is a method in which the polyol (b1-1) placed in a reaction vessel is heated under normal pressure or reduced pressure to remove moisture, and then the polyisocyanate (b1-2) is supplied all at once or in portions and reacted.

[0220] The reaction of polyol (b1-1) with polyisocyanate (b1-2) is preferably carried out in such a manner that the equivalent ratio (NCO / OH equivalent ratio) of the isocyanate groups (NCO) in polyisocyanate (b1-2) to the hydroxyl groups (OH) in polyol (b1-1) is in the range of 1.0 to 20.0, more preferably 1.1 to 13.0, even more preferably 1.2 to 5.0, and particularly preferably 1.5 to 3.0.

[0221] The reaction conditions for the polyol (b1-1) and the polyisocyanate (b1-2) are not particularly limited and can be appropriately selected taking into consideration various conditions such as safety, quality, and cost. The reaction temperature is preferably 70 to 120°C, and the reaction time is preferably 30 minutes to 5 hours.

[0222] When reacting the polyol (b1-1) with the polyisocyanate (b1-2), a catalyst such as a tertiary amine catalyst or an organometallic catalyst may be used as needed.

[0223] The reaction may be carried out in a solvent-free environment or in the presence of an organic solvent. The organic solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the organic solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone; ether ester solvents such as methyl cellosolve acetate and butyl cellosolve acetate; aromatic hydrocarbon solvents such as toluene and xylene; and amide solvents such as dimethylformamide and dimethylacetamide. These may be used alone or in combination of two or more.

[0224] The organic solvent may be removed during the production of the polyurethane resin (b1) or after the production of the polyurethane (b1) by an appropriate method such as heating under reduced pressure or drying at normal pressure.

[0225] (Other ingredients) The substrate layer may optionally contain other components in addition to the resins described above. The other components in the substrate layer are not particularly limited and can be appropriately selected as long as they do not impair the properties of the pressure-sensitive adhesive tape. Examples include tackifying resins; polymers other than the resins described above; crosslinking agents, antioxidants, UV absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, antifoaming agents, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, additives such as organic pigments, inorganic pigments, pigment dispersants, silica beads, and organic beads; and inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony pentoxide. These may be used alone or in combination of two or more.

[0226] The content of other components in the base layer can be appropriately selected within a range that does not impair the properties of the adhesive tape.

[0227] 3. Any configuration The adhesive tape of this embodiment essentially comprises a substrate layer and a pressure-sensitive adhesive layer provided on at least one surface of the substrate layer, but may also comprise a release sheet on the surface of the pressure-sensitive adhesive layer opposite the substrate layer. The release sheet is not particularly limited and can be appropriately selected depending on the purpose. Examples include paper such as kraft paper, glassine paper, and wood-free paper; resin films such as polyethylene, polypropylene (biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP)), and polyethylene terephthalate (PET); laminated paper in which the above-mentioned paper and a resin film are laminated; and paper in which the above-mentioned paper has been sealed with clay or polyvinyl alcohol and one or both sides of which has been subjected to a release treatment with a silicone resin or the like. These may be used alone or in combination of two or more.

[0228] The physical properties and thickness of the pressure-sensitive adhesive tape specified in this specification refer to the physical properties and thickness of the pressure-sensitive adhesive tape excluding the release liner.

[0229] 4. Adhesive tape The adhesive tape of the present embodiment is not particularly limited in shape or size as long as it comprises a base layer and a pressure-sensitive adhesive layer on at least one surface of the base layer, and includes, for example, an adhesive tape having a shape and size suitable for attachment to a predetermined adherend (for example, an adhesive tape in a state after being punched) and a long sheet-like adhesive tape (for example, an adhesive tape before being processed into a specific shape). Furthermore, the adhesive tape of the present embodiment can be optionally provided with a non-adhesive gripping region, for example, for attachment to or removal from an adherend.

[0230] The (average) thickness of the pressure-sensitive adhesive tape of this embodiment is not particularly limited and can be appropriately selected depending on the (average) thicknesses of the pressure-sensitive adhesive layer and the base layer, but is preferably 20 to 1000 μm, more preferably 30 to 600 μm, even more preferably 50 to 400 μm, and particularly preferably 80 to 300 μm. By setting the thickness of the pressure-sensitive adhesive tape within the above range, the stretchability and removability when the pressure-sensitive adhesive tape is stretched horizontally relative to the adherend surface and peeled off can be improved, and excellent impact resistance and holding power can be exhibited.

[0231] In this specification, the "thickness of the adhesive tape" refers to the average thickness of a total of 25 points, measured by cutting the adhesive tape lengthwise at 5 locations at 100 mm intervals and widthwise at 5 locations at 100 mm intervals on each cut surface, using a TH-104 thickness meter for paper and film (manufactured by Tester Sangyo Co., Ltd.).

[0232] The hardness (Type A hardness (Shore A hardness)) of the pressure-sensitive adhesive tape of this embodiment is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 to 80, more preferably 20 to 75, and even more preferably 30 to 70. When the Shore A hardness of the pressure-sensitive adhesive tape is within the above-mentioned preferred range, the pressure-sensitive adhesive tape can be easily peeled off. On the other hand, if the Shore A hardness is less than 10, the pressure-sensitive adhesive tape may tear when stretched to peel it off, and if it exceeds 80, when an attempt is made to stretch the pressure-sensitive adhesive tape to make it removable, the stress required for stretching may become too high, making it impossible to remove.

[0233] The rubber hardness of the adhesive tape is Shore A hardness, and refers to a value measured in accordance with JIS K 6253 using a durometer (spring type rubber hardness tester) (model: GS-719G, manufactured by Teclock Corporation).

[0234] The stress at 25% elongation of the pressure-sensitive adhesive tape of this embodiment is preferably 0.15 to 10 MPa, more preferably 0.16 to 10 MPa, even more preferably 0.17 to 5 MPa, and most preferably 0.18 to 4.5 MPa. When the stress at 25% elongation of the pressure-sensitive adhesive tape is 0.15 MPa to 10 MPa, the pressure-sensitive adhesive tape can have an adhesive strength suitable for the pressure-sensitive adhesive tape, and can be relatively easily peeled off even during stretch-peeling. On the other hand, when the stress at 25% elongation of the pressure-sensitive adhesive tape is less than 0.15 MPa, there is a risk that the pressure-sensitive adhesive tape will peel off when a load is applied in the shear direction of the pressure-sensitive adhesive tape while fixing hard adherends together. Furthermore, when the stress at 25% elongation of the pressure-sensitive adhesive tape exceeds 10 MPa, the force required to stretch the pressure-sensitive adhesive tape when peeling it off tends to be excessive.

[0235] The stress at 25% elongation of adhesive tape refers to the stress value measured when the adhesive tape is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the length direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH, and stretched to 25%.

[0236] The breaking stress of the pressure-sensitive adhesive tape of this embodiment is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 to 100.0 MPa, more preferably 3 to 90.0 MPa, even more preferably 5 to 80.0 MPa, and particularly preferably 10 to 80.0 MPa. When the breaking stress of the pressure-sensitive adhesive tape is within the above-mentioned preferred range, the pressure-sensitive adhesive tape can be prevented from tearing even when it is rapidly stretched to be peeled off, and the load for stretching the pressure-sensitive adhesive tape does not become excessive, making the peeling operation easy. If the breaking stress of the pressure-sensitive adhesive tape is too small, the pressure-sensitive adhesive tape may tear when it is rapidly stretched to be peeled off. If the breaking stress of the pressure-sensitive adhesive tape is too large, the pressure-sensitive adhesive tape may not be stretched sufficiently to be peeled off when it is stretched to be peeled off. In particular, in the pressure-sensitive adhesive tape of this embodiment, by making the breaking stress of the pressure-sensitive adhesive tape more than 5 MPa, preferably 10 MPa or more, the drop resistance is improved, and when the pressure-sensitive adhesive tape is stretched to peel off from a smooth surface or a matte surface, even when the tape is stretched to peel off in the vertical direction, which increases adhesion and makes cohesive failure more likely, in addition to the horizontal direction, the pressure-sensitive adhesive tape is less likely to tear during stretching, exhibiting good removability and increasing the degree of freedom in the stretching angle relative to the adherend surface. Note that the force required to stretch and deform the pressure-sensitive adhesive tape also depends on the thickness of the pressure-sensitive adhesive tape; for example, even when an adhesive tape that is thick and has a high breaking stress is stretched to make it removable, it may not be stretched sufficiently and may not be removably.

[0237] The breaking stress of adhesive tape refers to the stress value measured when the tape is punched into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled lengthwise at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH, until it breaks.

[0238] The breaking elongation of the pressure-sensitive adhesive tape of this embodiment is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 400 to 2000%. When the breaking elongation of the pressure-sensitive adhesive tape is 400% or more, even when the pressure-sensitive adhesive tape is firmly adhered to an adherend, excessive stress caused by stretching the pressure-sensitive adhesive tape in the horizontal to vertical direction relative to the adherend surface can be suppressed when the pressure-sensitive adhesive tape is removably attached, allowing the tape to be stretched with a moderate force and the pressure-sensitive adhesive tape to be easily peeled without excessive stretching. On the other hand, when the breaking elongation is 2000% or less, the distance stretched in the horizontal to vertical direction relative to the adherend surface when the pressure-sensitive adhesive tape is removably attached is not too long, allowing work to be done in a small space. Among these, the breaking elongation of the pressure-sensitive adhesive tape is more preferably 500 to 1800%, and even more preferably 600 to 1200%. By keeping the thickness within the above range, when the adhesive tape is stretched horizontally to vertically relative to the surface of the adherend and peeled off, the adhesive tape does not break and the stretching distance does not become too long, thereby further improving workability.

[0239] The breaking elongation of adhesive tape refers to the tensile elongation measured when the adhesive tape is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the lengthwise direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH, until breaking.

[0240] The pressure-sensitive adhesive tape of this embodiment has excellent impact resistance, particularly excellent drop impact resistance. Excellent drop impact resistance means that when articles bonded via the pressure-sensitive adhesive tape are dropped from a desired height, the bonded state of the articles can be maintained even when subjected to impact upon dropping. Drop impact resistance can be confirmed, for example, by the method described in the "Evaluation of Drop Impact Resistance" section of the Examples section below. In the drop impact resistance evaluation, the height of the impact point at which peeling or destruction of the pressure-sensitive adhesive tape occurs can be appropriately selected within a range that does not impair the effects of the present invention. However, since particularly excellent drop impact resistance can be obtained, a height of 50 cm or more is preferred, particularly 60 cm or more is preferred, 70 cm or more is even more preferred, 80 cm or more is even more preferred, and 120 cm or more is particularly preferred.

[0241] The storage modulus G' (23°C) of the pressure-sensitive adhesive tape of this embodiment is 1.0 × 10 4 ~1.0×10 8 Pa, preferably 5.0×10 4 ~5.0×10 7 Pa, more preferably 1.0×10 5 ~1.0×10 7 More preferably, it is 3.0×10 Pa. 5 ~8.0×10 6 It is even more preferable that the storage modulus G' (23°C) of the pressure-sensitive adhesive tape is within the above range. When the pressure-sensitive adhesive tape has a storage modulus G' (23°C) within the above range, the pressure-sensitive adhesive tape can easily conform to distortions of the adherend and excellent adhesive strength can be easily obtained, and the dimensional stability of the pressure-sensitive adhesive tape can also be ensured, resulting in favorable application workability.

[0242] The 180° peel adhesive strength of the pressure-sensitive adhesive tape of this embodiment is preferably 3 N / 20 mm to 50 N / 20 mm, more preferably 5 N / 20 mm to 45 N / 20 mm, and even more preferably 7 N / 20 mm to 40 N / 20 mm. When the 180° peel adhesive strength is within the above-mentioned preferred range, the pressure-sensitive adhesive tape has an appropriate adhesive strength without peeling or slippage from the adherend, and when stretched horizontally relative to the adhesive surface of the adherend and re-peelable, the tape can be easily peeled off without leaving any adhesive residue on the adherend. The 180° peel adhesive strength of the pressure-sensitive adhesive tape refers to the value measured in accordance with JIS Z 0237, and is measured using a pressure-sensitive adhesive tape cut to a size of 20 mm wide and 100 mm long. In an environment of 23°C and 50% RH, the adhesive surface of the pressure-sensitive adhesive sheet to be measured is pressed against the surface of a SUS plate by rolling a 2 kg roller back and forth once, and then left in an environment of 23°C and 50% RH for 1 hour.The peel strength [N / 20 mm width] is then measured using a tensile tester in accordance with JIS Z 0237:2000 at a pulling speed of 300 mm / min and a peel angle of 180 degrees.If the pressure-sensitive adhesive tape is double-sided, a 25 μm thick polyethylene terephthalate (PET) film is attached to the other adhesive surface, and the adhesive surface to be measured is then pressed against the SUS plate for measurement.

[0243] The pressure-sensitive adhesive tape of this embodiment can be applied to not only smooth surfaces of adherends but also matte surfaces, and can be easily peeled off without tearing or leaving adhesive residue on the adherend by stretching it horizontally relative to the adherend. In particular, when the adherend surface is a matte surface, adhesion increases over time, making it difficult to remove. However, the pressure-sensitive adhesive tape of this embodiment has a laminated structure consisting of a pressure-sensitive adhesive layer containing a predetermined composition and a substrate layer satisfying predetermined physical properties, and therefore exhibits good adhesion to matte surfaces while being easily stretched for removal. The term "smooth surface" as used herein means that the arithmetic surface roughness Ra of the adherend surface is less than 0.20 μm, preferably 0.15 μm or less, and more preferably 0.10 μm or less. Furthermore, the term "matte surface" means that the arithmetic surface roughness Ra of the adherend surface is 0.20 μm or more, preferably 0.25 μm or more, and more preferably 0.30 μm or more. The arithmetic surface roughness Ra of the adherend is a value measured by the method described in the Examples section below.

[0244] The pressure-sensitive adhesive tape of the present embodiment preferably has a shear adhesive strength of 1 MPa or more, preferably 0.7 to 4.0 MPa, more preferably 1.0 to 4.0 MPa, and even more preferably 1.5 to 4.0 MPa. When the shear adhesive strength is within the above preferred range, it is possible to easily achieve both high load-holding power and adhesiveness.

[0245] The shear adhesive strength of an adhesive tape can be measured by the following method. First, the adhesive tape is cut into a piece 20 mm wide x 20 mm long and attached to the surface of a clean, smooth stainless steel plate 1 (hairline polished with #360 waterproof abrasive paper) in an atmosphere of 23°C and 50% RH so that the adhesive area is 20 mm x 20 mm. The opposite side is attached to the surface of a clean, smooth stainless steel plate 2 (hairline polished with #360 waterproof abrasive paper) in an area of ​​20 mm x 20 mm. Then, the two are pressed together by moving them back and forth with a 5 kg roller once, and left in an environment of 23°C for 24 hours to prepare a test piece. With the stainless steel plate 1 constituting the test piece fixed, a Tensilon tensile tester is used to measure the shear adhesive strength when the stainless steel plate 2 is pulled in the shear direction of the adhesive tape at a rate of 300 mm / min in an atmosphere of 23°C and 50% RH.

[0246] 5. Manufacturing method of adhesive tape The method for producing the pressure-sensitive adhesive tape of the present embodiment is not particularly limited and can be appropriately selected from known methods. The method for producing the pressure-sensitive adhesive tape of the present embodiment preferably includes a pressure-sensitive adhesive layer forming step, a base layer forming step, and a lamination step, and further includes other layer forming steps as necessary. The pressure-sensitive adhesive tape can also be produced by a multilayer simultaneous formation step in which the pressure-sensitive adhesive layer forming step and the base layer forming step are carried out simultaneously.

[0247] The pressure-sensitive adhesive layer forming step is not particularly limited as long as it can form a pressure-sensitive adhesive layer and can be appropriately selected depending on the purpose, and examples include methods of forming a pressure-sensitive adhesive layer on the surface of a release sheet by heat pressing, extrusion casting, uniaxial stretching, sequential secondary stretching, simultaneous biaxial stretching, inflation, tube printing, calendaring, solution printing, etc. Among these, extrusion casting and solution printing are preferred.

[0248] The base layer forming step is not particularly limited as long as it can form a base layer and can be appropriately selected depending on the purpose, and examples include a heat press method, a casting method using extrusion molding, a uniaxial stretching method, a sequential secondary stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, a calendar method, and a solution method. These methods may be used alone or in combination of two or more. Among these, the casting method using extrusion molding, the inflation method, the tube method, the calendar method, and the solution method are preferred in terms of imparting suitable flexibility and extensibility to the base layer.

[0249] The substrate layer may be surface-treated in order to further improve adhesion to the pressure-sensitive adhesive layer.

[0250] The surface treatment method is not particularly limited and can be appropriately selected from known methods as long as it does not impair the properties of the adhesive tape. Examples include sandblasting, surface polishing / rubbing, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet irradiation treatment, and oxidation treatment.

[0251] The lamination step is a step of laminating a substrate layer and a pressure-sensitive adhesive layer. The method for laminating the substrate layer and the pressure-sensitive adhesive layer is not particularly limited and can be appropriately selected from known methods, such as a method of laminating the substrate layer and the pressure-sensitive adhesive layer attached to the release sheet formed in the pressure-sensitive adhesive layer-forming step by applying pressure.

[0252] 6.Applications The pressure-sensitive adhesive tape of this embodiment can be attached to the surface of an object (adherend) and stretched relative to the surface, allowing it to be removed from the object (adherend). Alternatively, the pressure-sensitive adhesive tape of this embodiment can be used to join two objects (adherends) and stretched from between the two objects (adherends), allowing it to be removed from the two objects. In either case, the pressure-sensitive adhesive tape is preferably stretched at least horizontally, and more preferably at an angle of 0° to 90° relative to the adherend surface.

[0253] The pressure-sensitive adhesive tape of the present embodiment can be suitably used for component fixing and temporary fixing in various industrial fields, such as fixing metal plates constituting relatively large electronic devices such as flat-screen televisions, home appliances, and office automation equipment, fixing exterior parts to housings, and fixing exterior parts and rigid parts such as batteries to relatively small electronic devices such as portable electronic terminals, cameras, and personal computers, as well as for applications such as labels displaying product information.

[0254] Although the embodiments of the present invention have been described above, the pressure-sensitive adhesive tape according to the present invention is not limited to the above examples and can be modified as appropriate. [Example]

[0255] The present invention will be described in detail below using examples, but the scope of the present invention is not limited to the following examples.

[0256] 1. Evaluation Method The evaluation methods used in the examples and comparative examples are shown below.

[0257] (1) Storage modulus G' of acrylic copolymers (1) to (4) The storage modulus G' of each of the acrylic copolymers (1) to (4) prepared in Synthesis Examples 1 to 4 described below was measured at 23°C and a frequency of 1 Hz by using a test piece prepared by applying each of the acrylic copolymers (1) to (4) described below using an applicator to a release liner (Film Vina 75E-0010GT) so that the thickness after drying would be 50 μm, and then stacking the resulting acrylic copolymer layers to a thickness of 2 mm. Parallel plates with a diameter of 7.9 mm were attached to a viscoelasticity tester, Ares 2kSTD, manufactured by Rheometrics, and the test piece was sandwiched between them.

[0258] (2) Storage modulus G' of the entire acrylic copolymer contained in the pressure-sensitive adhesive composition The storage modulus G' of the entire acrylic copolymer (one type alone or a mixture of two or more types) contained in the pressure-sensitive adhesive composition described below was measured at 23°C and a frequency of 1 Hz by using a test piece prepared by applying the pressure-sensitive adhesive composition (acrylic copolymer composition) before the addition of the tackifying resin, silicone particles, and ethyl acetate onto a release liner (Film Vina 75E-0010GT) using an applicator so that the thickness after drying would be 50 μm, and then stacking the acrylic copolymer composition layers to a thickness of 2 mm. Parallel plates with a diameter of 7.9 mm were attached to a viscoelasticity tester, Ares 2kSTD, manufactured by Rheometrics, and the test piece was sandwiched between them.

[0259] (3) Measurement of the breaking stress and breaking elongation of the base layer Each substrate layer was punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and the breaking stress and breaking elongation of the substrate layer were measured by pulling them in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH.

[0260] (4) Measurement of 50% modulus of the base layer Each substrate layer was punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and the stress value when the substrate layer was stretched by 50% was measured by pulling it in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH.

[0261] (5) Measurement of the thickness of the base layer and adhesive layer The base layer and adhesive layer were cut lengthwise at 5 locations at 100 mm intervals and widthwise at 5 locations, and the thickness of each cut surface was measured at 5 locations at 100 mm intervals widthwise using a TH-104 thickness measuring instrument for paper and film (manufactured by Tester Sangyo Co., Ltd.) The average value of the thickness at these 25 locations was used as the thickness of the base layer and adhesive layer.

[0262] (6) Measurement of the average particle size of the filler The average particle size (primary particle size) of the filler was measured using a measuring device (Microtrac) that uses a laser diffraction scattering method.

[0263] (7) Evaluation of high load holding power One side of each adhesive tape, cut to a 25mm wide x 25mm long piece, was bonded to a 25mm wide x 80mm wide SUS304 steel plate (JIS Z0237) by pressing it back and forth with a 5kg roller at a speed of 300mm per minute at room temperature, and then left at 23°C for 30 minutes. The other side of the test piece was then bonded to a 25mm wide x 80mm wide SUS304 steel plate (JIS Z0237) by pressing it back and forth with a 5kg roller at a speed of 300mm per minute at room temperature. The test piece was then left at 40°C for 30 minutes. A 5kg weight was then attached to the grip of the test piece, and the test was initiated by hanging it down. The time to drop was measured at 23°C and 50% RH. For high load retention, a drop time of 120 minutes or more was considered a pass. A drop time of less than 120 minutes was considered a fail.

[0264] (8) Removability 1 (initial removability from smooth adherend surfaces in the 0° and 90° directions) The adhesive tape, measuring 10 mm wide and 60 mm long, was applied to a clean, smooth aluminum plate (average surface roughness (Ra): 0.06 μm) with the 10 mm wide x 10 mm long portion of the tape serving as a grip, protruding from the aluminum plate. The other side of the tape was then applied to an aluminum plate with the same average surface roughness (Ra) and pressed back and forth with a roller once under a 2 kg load to prepare a test specimen. The test specimen had the grip of the adhesive tape protruding from the aluminum plate, and the remaining portion of the adhesive tape was sandwiched between the two aluminum plates. After application, the test specimen was left in an atmosphere of 40°C and 50% RH for 24 hours, and then the grip portion was stretched by hand in the longitudinal direction of the adhesive tape at a 90° angle to the adherend surface at a speed of approximately 300 mm / min at 23°C and 50% RH. For another test piece, the gripping portion of the adhesive tape was stretched by hand in the longitudinal direction of the adhesive tape at a speed of approximately 300 mm / min in a 0° direction relative to the adherend surface. Ten tests were conducted for each of the 0° and 90° stretching directions, and the degree of tape breakage and adhesive residue on the adherend after the tape was peeled off was visually evaluated according to the following criteria. (standard) ○: The adhesive tape was peeled off cleanly all 10 times without breaking or leaving any adhesive residue. △: The adhesive tape was peeled off cleanly 6 to 9 times without breaking or leaving any adhesive residue. ×: After 5 to 10 tries, the adhesive tape broke or adhesive residue remained, or the adhesive tape could not be stretched and peeled off.

[0265] (9) Removability 2 (initial removability from mat-covered surface in 0° and 90° directions) The adhesive tape, measuring 10 mm wide and 60 mm long, was applied to a clean, matte-printed aluminum plate (average surface roughness (Ra): 0.47 μm). The adhesive tape was applied so that the 10 mm wide and 10 mm long portion of the adhesive tape served as a gripping handle, protruding from the aluminum plate. The other side of the adhesive tape was then applied to an aluminum plate with the same average surface roughness (Ra), and a 2 kg load was applied and pressed back and forth with a roller once to prepare a test specimen. The test specimen had the adhesive tape's gripping handle protruding from the aluminum plate, and the adhesive tape portion other than the gripping handle was sandwiched between the two aluminum plates. After application, the test specimen was left in an atmosphere of 40°C and 50% RH for 24 hours. Then, at 23°C and 50% RH, the gripping handle was stretched by hand in the longitudinal direction of the adhesive tape at a 90° angle to the adherend surface at a speed of approximately 300 mm / min. For another test piece, the gripping portion of the adhesive tape was stretched by hand in the longitudinal direction of the adhesive tape at a speed of approximately 300 mm / min in a 0° direction relative to the adherend surface. Ten tests were conducted for each of the 0° and 90° stretching directions, and the degree of tape breakage and adhesive residue on the adherend after the tape was peeled off was visually evaluated according to the following criteria. (standard) ○: The adhesive tape was peeled off cleanly all 10 times without breaking or leaving any adhesive residue. △: The adhesive tape was peeled off cleanly 6 to 9 times without breaking or leaving any adhesive residue. ×: After 5 to 10 tries, the adhesive tape broke or adhesive residue remained, or the adhesive tape could not be stretched and peeled off.

[0266] The average surface roughness (a) of the adherends used in the evaluations of removability 1 and 2 was measured by the following method. The average surface roughness (Ra) of the smooth aluminum plate and matte-printed aluminum plate used as the adherend was evaluated using a three-dimensional roughness meter, Birdscan (VertScan R3300G, manufactured by Ryoka Systems Co., Ltd.). Measurements were taken at 10 arbitrary points on the adhesive surface of each aluminum plate with the tape, and the average of the obtained Ra values ​​was taken as the average surface roughness (Ra) of each aluminum plate. <Measurement conditions> Objective lens: 5x Internal lens: 0.5x Measurement mode: Phase mode Scan range: +10, -40 Wavelength filter: 520 Interpolation:Full Approximation surface: Polynomial approximation 1st order

[0267] (10) Drop impact resistance As shown in Figure 2, two pieces of each adhesive tape 1 were prepared, each cut to a length of 20 mm and a width of 2 mm. The adhesive tapes 1 were attached parallel to a polycarbonate plate 11 (length 50 mm, width 25 mm, thickness 0.2 mm, manufactured by Takiron C.I. Co., Ltd.) with a 40 mm gap between them. An acrylic plate 12 (length 50 mm, width 25 mm, thickness 2.5 mm, Acrylite L, colorless, manufactured by Mitsubishi Rayon Co., Ltd.) was attached to the opposite side of the adhesive tape 1, and the plate was pressed with a 4 kg weight for 10 seconds. After that, the plate was left to stand at 40°C and 50% RH for 24 hours to prepare test piece 10. Note that Figure 2 is a schematic plan view of the test piece 10 as seen from the acrylic plate 12 side, and for the sake of explanation, the position of the acrylic plate 12 is shifted in the illustration, but in reality, the outer periphery of the acrylic plate 12 and the outer periphery of the polycarbonate plate 11 were arranged so as to overlap in plan view.

[0268] Next, as shown in FIG. 3 (left), assuming an article with adhesive tape affixed to an adherend, a 300 g stainless steel load 21 was attached to the polycarbonate plate 11 side of test piece 10. A U-shaped measurement platform 22 (length t: 150 mm, width (no symbol in the figure): 100 mm, height h: 45 mm, thickness w: 5 mm, made of aluminum) was placed on the base of a DuPont impact tester (manufactured by Tester Sangyo Co., Ltd.), and test piece 10 was dropped onto U-shaped measurement platform 22 with the acrylic plate 12 side facing downward under conditions of 23°C and 50% RH. Arrow X in FIG. 3 (left) indicates the direction in which test piece 10 with load 21 attached was dropped. FIG. 3 (right) is a schematic diagram showing the state in which test piece 10 was dropped onto U-shaped measurement platform 22 with the acrylic plate 12 side facing downward. The highest point in the height direction of the U-shaped measuring table 22 was set as the reference point O, and the height H from the reference point O to the position P of the adhesive surface of the test piece 10 with the load 21 was changed in increments of 10 cm starting from 10 cm, and the test piece 10 was dropped five times at each height, and the height H at which peeling or breakage of the adhesive tape 1 on the test piece 10 was observed was measured.

[0269] 2. Preparation of Materials and Adhesive Compositions The materials for the substrate layer used in producing the pressure-sensitive adhesive tapes of Examples and Comparative Examples, as well as the preparation of the pressure-sensitive adhesive compositions, will be described below.

[0270] <Material for base material (1)> A nitrogen-purged, dried pressure vessel was charged with 3,000 mL of cyclohexane as a solvent and 9.2 mL of 10.5% by weight sec-butyllithium (cyclohexane solution) as an initiator. The mixture was heated to 60°C, and 100 mL of styrene was added and polymerized for 60 minutes. At the same temperature, 270 mL of isoprene and 350 mL of butadiene were then added, followed by a 90-minute reaction. Next, 100 mL of styrene was added at the same temperature and polymerized for 60 minutes. The polymerization was then terminated with 0.52 mL of methanol, yielding a polymerization reaction solution containing a block copolymer. To this reaction mixture, 29.3 g of palladium carbon (palladium loading: 5% by weight) was added as a hydrogenation catalyst, and the hydrogenation reaction was carried out at 150°C under a hydrogen pressure of 2 MPa for 10 hours. After cooling and depressurization, the palladium carbon was removed by filtration, and the filtrate was concentrated and further dried in vacuo to yield the substrate material (1). The obtained substrate material (1) was a resin composition (1) of styrene-ethylenebutylene-styrene copolymer and styrene-ethylenebutylene copolymer, in which the proportion of styrene-ethylenebutylene copolymer relative to the total amount of resin composition (1) was 0.5 mass%, the styrene-derived structural unit represented by the following chemical formula (A) was 29 mass%, the weight average molecular weight was 98,000, the molecular weight distribution was 1.03, and the hydrogenation rate was 98%.

[0271] [ka]

[0272] <Raw material for base material (2)> As the substrate material (2), a resin composition (2) consisting of a mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer (hereinafter sometimes referred to as "SIS") was used. The mixture contained 25% by weight of styrene-derived structural units represented by the above chemical formula (A), and the proportion of styrene-isoprene copolymer to the total amount of the resin composition (2) was 17% by weight.

[0273] <<Silicone filler (1)>> As the silicone filler (1), silicone resin / rubber composite particles (KMP-601, manufactured by Shin-Etsu Chemical Co., Ltd., volume average particle size: 12 μm, particle size distribution (D90 / D10): 4.4) with a silicone resin surface and silicone rubber interior were used.

[0274] <<Adhesive resin>> (Synthesis Example 1: Acrylic Copolymer (1)) A mixed solution was prepared in a 1000 ml flask with an argon atmosphere by adding 500 ml of dry toluene and 80 ml of a dry toluene solution containing 0.75 g of bis(pentamethylcyclopentadienyl)samarium tetrahydrofuranate complex [(C5Me5)2SmMe(THF)] as a polymerization initiator. 12.0 ml of methyl methacrylate (MMA) was added to the mixed solution at 0 °C and stirred at 0 °C for 30 minutes. A 20 ml sample was then taken from the system (Sample 1). After polymerization of the MMA, the polymerization reaction system was cooled to -78 °C, and 88.0 ml of n-butyl acrylate (nBA) was added as the second monomer. The mixture was stirred at -78 °C for 3 hours. A 20 ml sample was then taken from the system (Sample 2). After polymerization of the nBA, 12.0 ml of MMA was added as the third monomer at -78 °C and the mixture was stirred. After the solution became homogeneous, it was heated to 0°C and stirred for another hour. 50 ml of methanol was added to the resulting reaction mixture, and the mixture was allowed to react at room temperature for 2 hours to terminate the polymerization. The reaction solution after termination of the polymerization was poured into a large amount of hexane, and a white precipitate was obtained. A portion of the white precipitate was then sampled (Sample 3).

[0275] NMR, DSC, and GPC (gel permeation chromatography) measurements were performed on each of the polymers in Samples 1 to 3. Based on the measurement results, the number average molecular weight (Mn), the PMMA / PnBA (polymethyl methacrylate block / polyn-butyl acrylate block) ratio, etc. were determined, and it was confirmed that the white precipitate was an acrylic triblock copolymer (PMMA-b-PnBA-b-PMMA) of polymethyl methacrylate (PMMA) block-polyn-butyl acrylate (PnBA) block-polymethyl methacrylate (PMMA) block. The glass transition temperature of the PMMA block of the acrylic copolymer (1) (PMMA-b-PnBA-b-PMMA, hereafter referred to as triblock copolymer (1)) was 113.7°C, and the glass transition temperature of the PnBA block was -46.8°C. The weight average molecular weight (Mn) of the entire triblock copolymer (1) was 95,936, and the Mw / Mn (molecular weight distribution) of the entire triblock copolymer (1) was 1.09. The proportions of the polymer blocks in triblock copolymer (1) were confirmed to be PMMA (11% by mass), PnBA (78% by mass), and PMMA (11% by mass). The elastic modulus of triblock copolymer (1) represented by PMMA-b-PnBA-b-PMMA was 0.20 MPa.

[0276] (Synthesis Example 2: Acrylic Copolymer (2)) A mixed solution was prepared in a 1000 ml flask with an argon atmosphere by adding 500 ml of dry toluene and 80 ml of a dry toluene solution containing 0.75 g of bis(pentamethylcyclopentadienyl)samarium tetrahydrofuranate complex [(C5Me5)2SmMe(THF)] as a polymerization initiator. 4.3 ml of methyl methacrylate (MMA) was added to the mixed solution at 0 °C and stirred at 0 °C for 30 minutes. A 20 ml sample was taken from the system (Sample 7). After the polymerization of MMA, the reaction system was cooled to -78 °C, and 80.0 ml of n-butyl acrylate (nBA) was added as the second monomer. The mixture was stirred at -78 °C for 3 hours. A 20 ml sample was taken from the system (Sample 8). After the polymerization of nBA, 4.3 ml of MMA was added as the third monomer at -78 °C and the mixture was stirred. After the solution became homogeneous, it was heated to 0°C and stirred for another hour. 50 ml of methanol was added to the resulting reaction mixture, and the mixture was allowed to react at room temperature for 2 hours to terminate the polymerization. The reaction solution after the termination of the polymerization was poured into a large amount of hexane, and a white precipitate was obtained. A portion of the white precipitate was then sampled (Sample 9).

[0277] NMR, DSC, and GPC (gel permeation chromatography) measurements were performed on each of the polymers in Samples 7 to 9. Based on the measurement results, the number average molecular weight (Mn), the PMMA / PnBA (polymethyl methacrylate block / polyn-butyl acrylate block) ratio, etc. were determined, and it was confirmed that the white precipitate was an acrylic triblock copolymer (PMMA-b-PnBA-b-PMMA) having polymethyl methacrylate (PMMA) block-polyn-butyl acrylate (PnBA) block-polymethyl methacrylate (PMMA) block. The glass transition temperature of the PMMA block portion of the acrylic copolymer (2) (PMMA-b-PnBA-b-PMMA, hereafter referred to as triblock copolymer (2)) was 101.2°C, and the glass transition temperature of the PnBA block portion was -47.2°C. The weight average molecular weight (Mn) of the entire triblock copolymer (2) was 75,609, and the Mw / Mn (molecular weight distribution) of the entire triblock copolymer (2) was 1.09. The proportions of the polymer blocks in triblock copolymer (2) were confirmed to be PMMA (5% by mass), PnBA (90% by mass), and PMMA (5% by mass). The elastic modulus of triblock copolymer (2) represented by PMMA-b-PnBA-b-PMMA was 0.02 MPa.

[0278] (Synthesis Example 3: Acrylic Copolymer (3)) A mixed solution was prepared in a 1000 ml flask with an argon atmosphere by adding 500 ml of dry toluene and 80 ml of a dry toluene solution containing 0.75 g of bis(pentamethylcyclopentadienyl)samarium tetrahydrofuranate complex [(C5Me5)2SmMe(THF)] as a polymerization initiator. 16.5 ml of methyl methacrylate (MMA) was added to the mixed solution at 0 °C and stirred at 0 °C for 30 minutes. A 20 ml sample was then taken from the system (Sample 4). After the MMA polymerization, the polymerization reaction system was cooled to -78 °C, and 75.0 ml of n-butyl acrylate (nBA) and 63.0 ml of 2-ethylhexyl acrylate (2EHA) were added as the second monomer. The mixture was stirred at -78 °C for 3 hours. A 20 ml sample was then taken from the system (Sample 5). After the polymerization of nBA, 16.5 ml of MMA was added to the polymerization system as the third monomer at -78°C, and the solution was stirred. After the solution became homogeneous, it was heated to 0°C and stirred for an additional hour. The polymerization was terminated by adding 50 ml of methanol to the resulting reaction mixture and reacting at room temperature for 2 hours. The reaction solution after polymerization termination was poured into a large amount of hexane, and a white precipitate was obtained. A portion of the white precipitate was then sampled (Sample 6).

[0279] NMR, DSC, and GPC (gel permeation chromatography) measurements were performed on each of the polymers in Samples 4 to 6. Based on the measurement results, the number average molecular weight (Mn), PMMA / PnBA / P2EHA (polymethyl methacrylate / polyn-butyl acrylate / poly2-ethylhexyl acrylate) ratio, etc. were determined, and it was confirmed that the white precipitate was an acrylic triblock copolymer (PMMA-b-PnBA / 2EHA-b-PMMA) of polymethyl methacrylate (PMMA) block-polyn-butyl acrylate (PnBA) / poly2-ethylhexyl acrylate (2EHA) block-polymethyl methacrylate (PMMA) block. The glass transition temperatures of the PMMA block and PnBA block of the acrylic copolymer (3) (PMMA-b-PnBA / 2EHA-b-PMMA, hereafter referred to as triblock copolymer (3)) were 105.8°C and -55.6°C, respectively. The weight-average molecular weight (Mn) of the entire triblock copolymer (3) was 144,560, and the Mw / Mn (molecular weight distribution) of the entire triblock copolymer (3) was 1.08. The proportions of the polymer blocks in triblock copolymer (3) were confirmed to be PMMA (10% by mass), PnBA (44% by mass), 2EHA (36% by mass), and PMMA (10% by mass). The elastic modulus of triblock copolymer (3) represented by PMMA-b-PnBA / 2EHA-b-PMMA was 0.15 MPa.

[0280] (Synthesis Example 4: Acrylic Copolymer (4)) 97.97 parts by mass of n-butyl acrylate, 2 parts by mass of acrylic acid, and 0.03 parts by mass of 4-hydroxybutyl acrylate were added to ethyl acetate containing 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator, and solution polymerization was carried out at 77°C for 8 hours to obtain acrylic random copolymer (4). Mw was 700,000, and Mw / Mn (molecular weight distribution) was 4.7. The elastic modulus of acrylic random copolymer (4) was 0.08 MPa.

[0281] The storage modulus of each of the acrylic copolymers obtained in Synthesis Examples 1 to 4 is shown in Table 1 below.

[0282] [Table 1]

[0283] <Preparation of Pressure-Sensitive Adhesive Composition> Adhesive composition (1) A pressure-sensitive adhesive composition (1) with a solid content of 40% by mass was obtained by adding 60 parts by mass of the triblock copolymer (1) obtained in Synthesis Example 1 described above, 40 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring to homogeneity.

[0284] Adhesive composition (2) A pressure-sensitive adhesive composition (2) with a solid content of 40% by mass was obtained by adding 40 parts by mass of the triblock copolymer (1) obtained in Synthesis Example 1 described above, 60 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring until homogeneous, thereby obtaining a pressure-sensitive adhesive composition (2) with a solid content of 40% by mass.

[0285] Adhesive composition (3) A pressure-sensitive adhesive composition (3) with a solid content of 40% by mass was obtained by adding 60 parts by mass of the triblock copolymer (3) obtained in Synthesis Example 1 described above, 40 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring to homogeneity.

[0286] Adhesive composition (4) A pressure-sensitive adhesive composition (4) with a solid content of 40% by mass was obtained by adding 80 parts by mass of the triblock copolymer (1) obtained in Synthesis Example 1 described above, 20 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring to homogeneity.

[0287] Adhesive composition (5) A pressure-sensitive adhesive composition (5) with a solid content of 40% by mass was obtained by adding 60 parts by mass of the triblock copolymer (1) obtained in Synthesis Example 1 described above, 40 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (2) (YS Polystar T130, Yasuhara Chemical Co., Ltd., softening point 130°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring until homogeneous, thereby obtaining a pressure-sensitive adhesive composition (5) with a solid content of 40% by mass.

[0288] Adhesive composition (6) A pressure-sensitive adhesive composition (6) with a solid content of 40% by mass was obtained by adding 80 parts by mass of the triblock copolymer (3) obtained in Synthesis Example 1 described above, 20 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring to homogeneity.

[0289] Adhesive composition (7) A pressure-sensitive adhesive composition (7) with a solid content of 40% by mass was obtained by adding 100 parts by mass of the triblock copolymer (1) obtained in Synthesis Example 1 described above, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring until homogeneous.

[0290] Adhesive composition (8) A pressure-sensitive adhesive composition (8) with a solid content of 40% by mass was obtained by adding 100 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 1 described above, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring to homogeneity.

[0291] Adhesive composition (9) To 95 parts by mass of the triblock copolymer (1) obtained in Synthesis Example 1 described above, 5 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) were added ethyl acetate, and the mixture was stirred and mixed to homogeneity, thereby obtaining a pressure-sensitive adhesive composition (9) with a solid content of 40% by mass.

[0292] Adhesive composition (10) To 10 parts by mass of the triblock copolymer (1) obtained in Synthesis Example 1 described above, 90 parts by mass of the triblock copolymer (2) obtained in Synthesis Example 2, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) were added ethyl acetate, and the mixture was stirred and mixed to homogeneity, thereby obtaining a pressure-sensitive adhesive composition (10) with a solid content of 40% by mass.

[0293] Adhesive composition (11) To 100 parts by mass of the acrylic random copolymer obtained in Synthesis Example 4 described above, 42 parts by mass of a rosin-based tackifying resin (Haritac PCJ, manufactured by Harima Chemicals Co., Ltd., softening point 135°C), 34 parts by mass of silicone particles (1), and ethyl acetate were added and stirred until homogeneous, thereby obtaining a mixture (1) with a solid content of 40% by mass. Next, to 100 parts by mass of the mixture (1), 1.6 parts by mass of a crosslinking agent (Burnoc D-40, manufactured by DIC Corporation; trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by weight, nonvolatile content 40% by weight) was added, and then stirred until homogeneous, thereby obtaining a composition for adhesive layer (11).

[0294] Adhesive composition (12) A pressure-sensitive adhesive composition (12) with a solid content of 40% by mass was obtained by adding 100 parts by mass of the triblock copolymer (3) obtained in Synthesis Example 1 described above, 42 parts by mass of a terpene phenol-based tackifying resin (1) (Tamanol 803L, Arakawa Chemical Industries, Ltd., softening point 150°C), and 34 parts by mass of silicone particles (1) to ethyl acetate and stirring to homogeneity.

[0295] 3.Adhesive tape manufacturing Example 1 The substrate material (1) was diluted with toluene to a solid content of 20% by mass to prepare a substrate layer-forming coating solution (1). The coating solution (1) was then applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd.) using an applicator so that the thickness after drying was 50 μm, and the coating solution (1) was dried at 65° C. for 15 minutes to prepare a substrate (1A). The breaking strength, breaking elongation, and 50% modulus of the substrate (1A) were measured using the above-mentioned measurement methods.

[0296] Next, the pressure-sensitive adhesive composition (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd.) using an applicator to a thickness of 50 μm after drying, and dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive layer with a release liner. The volume ratio of the filler to the total volume of the pressure-sensitive adhesive layer was 21% by volume.

[0297] Next, both sides of the substrate (1A) were subjected to corona treatment so that the wet tension was 48 mN / m, and then the above-mentioned pressure-sensitive adhesive layer was bonded to each side of the substrate (1A) to create a laminated structure of release liner / pressure-sensitive adhesive layer / substrate (1A) / pressure-sensitive adhesive layer / release liner, and a pressure of 0.2 MPa was applied to the laminated structure to laminate the pressure-sensitive adhesive layers onto both sides of the substrate (1A), thereby producing the pressure-sensitive adhesive tape of Example 1 in the form of a double-sided pressure-sensitive adhesive tape.

[0298] Example 2 An adhesive tape of Example 2 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, adhesive composition (1) was changed to adhesive composition (2).

[0299] Example 3 An adhesive tape of Example 3 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, the adhesive composition (1) was changed to the adhesive composition (3).

[0300] Example 4 An adhesive tape of Example 4 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, adhesive composition (1) was changed to adhesive composition (4).

[0301] Example 5 An adhesive tape of Example 5 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, the adhesive composition (1) was changed to the adhesive composition (5).

[0302] Example 6 The coating solution (1) for forming the base layer was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., the same applies hereinafter) using an applicator so that the thickness after drying would be 70 μm, and the coating solution was dried at 65° C. for 15 minutes to prepare a base material (1B). The breaking strength, breaking elongation, and 50% modulus of the base material (1B) were measured using the above-mentioned measurement methods.

[0303] The adhesive tape of Example 6 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, the substrate (1A) was changed to the substrate (1B) and the thickness of the adhesive composition (1) after drying was changed to 40 μm.

[0304] Example 7 The substrate material (2) was diluted with toluene to a solid content of 30% by mass to prepare a coating solution (2). The coating solution (2) was then applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd.) using an applicator so that the thickness after drying was 50 μm, and the coating solution (2) was dried at 65° C. for 15 minutes to prepare a substrate (2). The breaking strength, breaking elongation, and 50% modulus of the substrate (2) were measured using the above-mentioned measurement methods.

[0305] An adhesive tape of Example 7 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, the substrate (1A) was changed to the substrate (2).

[0306] Example 8 An adhesive tape of Example 8 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, the adhesive composition (1) was changed to the adhesive composition (6).

[0307] Comparative Example 1 An adhesive tape of Comparative Example 1 was produced in the same manner as in Example 1, except that the adhesive composition (1) in the production of the adhesive tape of Example 1 was changed to the adhesive composition (7).

[0308] Comparative Example 2 An adhesive tape of Comparative Example 2 was produced in the same manner as in Example 1, except that the adhesive composition (1) in the production of the adhesive tape of Example 1 was changed to the adhesive composition (8).

[0309] Comparative Example 3 An adhesive tape of Comparative Example 3 was produced in the same manner as in Example 1, except that the adhesive composition (1) in the production of the adhesive tape of Example 1 was changed to the adhesive composition (9).

[0310] Comparative Example 4 An adhesive tape of Comparative Example 4 was produced in the same manner as in Example 1, except that the adhesive composition (1) in the production of the adhesive tape of Example 1 was changed to the adhesive composition (10).

[0311] Comparative Example 5 The adhesive tape of Comparative Example 5 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, the adhesive composition (1) was changed to the adhesive composition (7) and the substrate (1A) was changed to the substrate (2).

[0312] Comparative Example 6 The adhesive tape of Comparative Example 6 was produced by forming the adhesive tape into a double-sided adhesive tape in the same manner as in Example 1, except that the adhesive composition (1) in the production of the adhesive tape of Example 1 was changed to the adhesive composition (11), and then leaving it in a 40°C environment for 48 hours.

[0313] Comparative Example 7 An adhesive tape of Comparative Example 7 was produced in the same manner as in Example 1, except that in the production of the adhesive tape of Example 1, the adhesive composition (1) was changed to the adhesive composition (12).

[0314] The breaking strength, breaking elongation, and 50% modulus of each of the substrates (1A), (1B), and (2), as well as the results of evaluation of the pressure-sensitive adhesive tapes obtained in the Examples and Comparative Examples by the above-mentioned methods, are shown in Tables 2 and 3.

[0315] [Table 2]

[0316] [Table 3]

[0317] The pressure-sensitive adhesive tapes of Examples 1 to 8 had high high load holding power and excellent drop impact resistance, and were able to achieve both high load holding power and drop impact resistance, and also had good removability from smooth and matte surfaces. On the other hand, the pressure-sensitive adhesive tapes of Comparative Examples 1 to 7 were unable to achieve both high load holding power, high drop impact resistance, and removability from smooth and matte surfaces. [Explanation of symbols]

[0318] 1...adhesive tape, 2...adhesive layer, 3...base layer, 10...test piece, 11...polycarbonate plate, 12...acrylic plate, 21...load

Claims

1. a base layer and a pressure-sensitive adhesive layer on one or both sides of the base layer; the pressure-sensitive adhesive layer contains an acrylic block copolymer (X) having a storage modulus in the range of 0.10 MPa to 0.30 MPa, an acrylic block copolymer (Y) having a storage modulus in the range of 0.01 MPa to 0.05 MPa, and one or more fillers; the acrylic block copolymer (X) is a triblock copolymer having a polymer block [A1] composed of a methacrylic acid alkyl ester monomer unit and a polymer block [B1] composed of an acrylic acid alkyl ester monomer unit, the proportion of the polymer block [A1] in the acrylic block copolymer (X) is within the range of 10% by mass to 30% by mass, the acrylic block copolymer (Y) is a triblock or diblock copolymer having a polymer block [A2] composed of a methacrylic acid alkyl ester monomer unit and a polymer block [B2] composed of an acrylic acid alkyl ester monomer unit, the proportion of the polymer block [A2] in the acrylic block copolymer (Y) is within the range of 2% by mass to 16% by mass, the filler is a silicone-based filler, the total proportion of the acrylic block copolymer (X) and the acrylic block copolymer (Y) in the pressure-sensitive adhesive layer is 80% by mass or more, the content ratio of the acrylic block copolymer (X) to the acrylic block copolymer (Y) is within the range of 90 / 10 to 30 / 70, the base layer has a breaking stress in the range of 1 MPa to 100 MPa and a breaking elongation of 300% to 3000%, An adhesive tape that can be stretched and peeled off.

2. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the weight average molecular weight of the acrylic block copolymer (X) is within the range of 50,000 to 300,000.

3. 3. The pressure-sensitive adhesive tape according to claim 1, wherein the weight average molecular weight of the acrylic block copolymer (Y) is within the range of 30,000 to 200,000.

4. The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer contains one or more tackifying resins.

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