Adhesive tape, joint, and method for disassembling the joint

Abstract

To provide an adhesive tape that can be peeled easily and has peeling resistance in the thickness direction.SOLUTION: The inventive adhesive tape has a first adhesive layer, a first substrate layer and a foamed layer, and a third adhesive layer in this order. The first substrate layer has a strength at break of 1.0-100.0 MPa and an elongation at break of 400-1500%. The foam of the foamed layer has a 25% compression strength of 40-160 kPa and the foam has a tensile strength of 3.0-15.0 MPa.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive tape, a joint, and a method for disassembling a joint. [Background technology]

[0002] Adhesive tapes offer excellent workability and high adhesive reliability, and are therefore widely used as a joining means in various industrial fields such as office automation equipment, IT and home appliances, and automobiles for applications such as fixing parts, temporarily fixing parts, and labeling product information (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2001-89726 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Incidentally, in recent years, from the perspective of environmental protection, there has been a growing demand for the recycling and reuse of used products or defective products that occurred during the manufacturing process in various industrial fields such as home appliances and automobiles. When recycling and reusing various products, it is necessary to dismantle the product and remove each component, but when removing each component, it is necessary to peel off the adhesive tape used to fix the component or for labels. However, in recent years, adhesive tape has been placed in various places in products, and the work of peeling off the adhesive tape that adheres each component (substrate) has become complicated, and there is a demand for a reduction in work costs. Furthermore, adhesive tapes are required to be easy to remove, as well as resistant to peeling in the thickness direction of the tape. Specifically, the adhesive surfaces of the various components in a product to which the adhesive tape adheres (for example, the housing and the components fixed to the housing) may have gaps of varying sizes within the adhesive surface area due to slight distortions in the components. The adhesive tape is required to remain adhered to each component even if such gaps exist, and even if the distortion of the components or the size of the gaps fluctuates (resistance to peeling in the thickness direction of the tape) due to the elasticity of the tape itself.

[0005] Therefore, this disclosure is an invention made in view of the above problems, and aims to provide an adhesive tape that achieves both ease of peeling and resistance to peeling in the thickness direction, a joint that facilitates the peeling of the adhesive tape and can sufficiently maintain adhesion between adherends, and a method for disassembling the joint for easy disassembly of the joint. [Means for solving the problem]

[0006] [1] The present disclosure comprises, in order, a first adhesive layer, a first substrate layer, a foam layer and a third adhesive layer, The first base material layer has a breaking strength of 1.0 to 100.0 MPa and a breaking elongation of 400 to 1500%. The adhesive tape is characterized in that the 25% compressive strength of the foam in the foam layer is 40 to 160 kPa, and the tensile strength of the foam is 3.0 to 15.0 MPa. [2] In this embodiment, it is preferable to have a second adhesive layer between the first substrate layer and the foam layer. [3] In this embodiment, the first adhesive layer adjacent to the first substrate layer is formed from an adhesive composition containing filler particles with an average particle size of 10 to 40 μm and an adhesive resin, The amount of filler particles in the adhesive layer containing the filler particles is preferably 3 to 50 parts by mass per 100 parts by mass of the adhesive resin. [4] In this embodiment, the second adhesive layer adjacent to the first substrate layer is formed from an adhesive composition containing filler particles with an average particle size of 10 to 40 μm and an adhesive resin, The amount of filler particles in the adhesive layer containing the filler particles is preferably 3 to 50 parts by mass per 100 parts by mass of the adhesive resin. [5] In this embodiment, it is preferable to have a fourth adhesive layer between the second adhesive layer and the foam layer. [6] In this embodiment, it is preferable to have a second base material layer between the second adhesive layer and the fourth adhesive layer. [7] This embodiment is a bonding body comprising an adhesive tape as described in any of [1] to [6] above, a first adherend that adheres to the surface of the first adhesive layer of the adhesive tape, and a second adherend that adheres to the surface of the third adhesive layer of the adhesive tape. [8] This embodiment is a method for dismantling the joint described in [7] above, The method for dismantling a jointed body includes the step of stretching at least the first base material layer of the adhesive tape to separate the second adherend from the first adherend. [9] This embodiment is a bonding body comprising the adhesive tape described in [6] above, a first adherend that adheres to the surface of the first adhesive layer of the adhesive tape, and a second adherend that adheres to the surface of the third adhesive layer of the adhesive tape.

[10] This embodiment is a method for dismantling the joint described in [9] above, The method for dismantling a joint comprises the step of separating the second adherend from the first adherend by stretching at least the first base layer of the adhesive tape while leaving the second base layer of the adhesive tape on the surface of the second adherend. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an adhesive tape that facilitates peeling and maintains resistance to peeling in the thickness direction, a joint that facilitates the peeling of the adhesive tape and can sufficiently maintain adhesion between adherends, and a method for disassembling the joint for easy disassembly of the joint. [Modes for carrying out the invention]

[0008] The following describes embodiments of the present invention (hereinafter referred to as "this embodiment") in detail, but the present invention is not limited to this embodiment.

[0009] [Adhesive tape] The adhesive tape of this embodiment comprises, in order, a first adhesive layer, a first base layer, a foam layer, and a third adhesive layer, wherein the breaking strength of the first base layer is 1.0 to 100.0 MPa, the breaking elongation of the first base layer is 400 to 1500%, and the 25% compressive strength of the foam in the foam layer is 40 to 160 kPa, and the tensile strength of the foam is 3 to 15.0 MPa. Furthermore, it is preferable that the adhesive tape of this embodiment includes a second adhesive layer between the first base layer and the foam layer. Moreover, it is preferable that the adhesive tape of this embodiment includes a fourth adhesive layer between the second adhesive layer and the foam layer. And it is even more preferable that the adhesive tape of this embodiment includes a second base layer between the second adhesive layer and the fourth adhesive layer. The adhesive tape of this embodiment makes it possible to achieve both ease of peeling and resistance to peeling in the thickness direction. Specifically, in the adhesive tape of this embodiment, the breaking strength of the first base material layer is 1.0 to 100.0 MPa and the breaking elongation of the first base material layer is 400 to 1500%. When peeling the adhesive tape from between parts of a product to be reworked or recycled (hereinafter, the object to which the adhesive tape adheres will also be referred to as the first adherend and the second adherend), the first base material layer stretches sufficiently, and the first base material layer does not tear, allowing the first base material layer to be peeled (removed) from between the first adherend and the second adherend together with at least the first adhesive layer (preferably the first adhesive layer and an optional second adhesive layer). As a result, the first adherend and the second adherend can be easily separated and disassembled, and the peeling work of the adhesive tape can be facilitated. Furthermore, the foam layer has a 25% compressive strength of 40-160 kPa and a tensile strength of 3.0-15.0 MPa, which imparts appropriate elasticity to the adhesive tape. This allows the tape to maintain adhesion between components (first and second adherends) even with slight distortions in the components (resistance to adhesion) (resistance to peeling in the tape thickness direction). The following describes the first, second, third, and fourth embodiments of the adhesive tape of this embodiment.

[0010] 《Adhesive tape of the first embodiment》 The adhesive tape of the first embodiment according to this embodiment comprises, in order, a first adhesive layer, a first base material layer, a foam layer, and a third adhesive layer, wherein the breaking strength of the first base material layer is 1.0 to 100.0 MPa, the breaking elongation of the first base material layer is 400 to 1500%, the 25% compressive strength of the foam in the foam layer is 40 to 160 kPa, and the tensile strength of the foam is 3.0 to 15.0 MPa.

[0011] <First base layer> In the first embodiment, the adhesive tape comprises a first base layer between a first adhesive layer forming the adhesive surface on one side of the adhesive tape and a third adhesive layer forming the adhesive surface on the other side. The first base layer has a breaking strength of 1.0 to 100.0 MPa and a breaking elongation of 400 to 1500%.

[0012] In the first embodiment, the first substrate layer is not particularly limited as long as it has the above-mentioned properties, and can be appropriately selected from known materials that can be used for adhesive tapes. It is preferable that it contains the following first substrate material, and may also contain other components as needed. The first base material layer may be a single layer, or it may be a multi-layer structure of two, three, or more layers.

[0013] In the first embodiment, the first base material layer has a breaking strength of 1.0 to 100.0 MPa, preferably 5 to 95 MPa, more preferably 15 to 92 MPa, and even more preferably 25.0 to 90.0 MPa. A breaking strength of 1.0 MPa or higher ensures that when the adhesive tape is peeled off to separate and dismantle the first and second adherends, the first base material layer stretches sufficiently when pulled, allowing it to be peeled (removed) from between the first and second adherends without tearing the first base material layer. This allows for easy separation and dismantling of the first and second adherends. Furthermore, a breaking strength of 100.0 MPa or lower prevents excessive stress on the worker when pulling the adhesive tape. The breaking strength of the first base material layer is determined by punching out a dumbbell-shaped piece of the first base material layer with a gauge length of 20 mm and a width of 5 mm, and using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH, pulling it lengthwise at a tensile speed of 500 mm / min, and referring to the stress value measured when it breaks. Furthermore, the fracture strength can be adjusted by selecting appropriate materials and by methods such as stretching during the manufacturing process of the first base material layer.

[0014] In the first embodiment, the first base layer has a breaking elongation of 400 to 1500%, preferably 400 to 1400%, more preferably 500 to 1300%, and even more preferably 600 to 1200%. A breaking elongation (also referred to as breaking elongation) of 400% or more prevents excessive stress when peeling off the adhesive tape, even when the tape is firmly adhered to the substrate. Furthermore, a breaking elongation of 1500% or less prevents excessive stretching distance when peeling off the adhesive tape, allowing for work in a small space. The elongation at break of the first base material layer is measured when the first base material layer is punched out in 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, and then fractured. Furthermore, the elongation at break can be adjusted by selecting an appropriate material and by applying stretching during the manufacturing process of the first base layer.

[0015] In the first embodiment, the first base material layer preferably has a 100% modulus of 1 to 5 MPa, more preferably 1 to 4.5 MPa, and even more preferably 1 to 4 MPa. A 100% modulus of 1 MPa or higher suppresses problems associated with shape deformation such as slippage when a load is applied to the adhesive tape or adherend. Furthermore, a 100% modulus of 5 MPa or lower allows the worker to pull the adhesive tape off the adherend with relatively little force in the initial stage of peeling it off. The 100% modulus of the first base material layer refers to the stress value measured when the elongation is 100%, after punching out a dumbbell-shaped piece of the first base material layer with a gauge length of 20 mm and a width of 5 mm, and pulling it 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. Furthermore, the 100% modulus can be adjusted by selecting appropriate materials and by methods such as stretching during the manufacturing process of the first base material layer.

[0016] In the first embodiment, the first base material layer preferably has a rubber hardness of 20 to 90A, more preferably 30 to 85A, and even more preferably 60 to 85A. A rubber hardness of 20A or higher prevents the adhesive tape from tearing when it is stretched and peeled off. A rubber hardness of 90A or lower makes the first base material layer softer, which, for example, allows the adhesive tape to absorb impact more easily when an object to which the adhesive tape is attached is dropped, thus protecting the object from impact (improving the impact resistance of the adhesive tape). The rubber hardness of the first base layer is measured on a Shore A scale, using a durometer (spring-type rubber hardness tester) (model: GS-719G, manufactured by Teclock Co., Ltd.) in accordance with JIS K 6253. Furthermore, the rubber hardness can be adjusted by selecting materials as appropriate, for example, by changing the molecular weight of the resin or, if styrene monomer units are included, by changing those monomer units.

[0017] The first base layer has a thickness of 10 to 1000 μm, preferably 10 to 300 μm, and more preferably 20 to 200 μm. A thickness of 10 μm or more ensures the strength of the adhesive tape, while a thickness of 1000 μm or less avoids the problem of the tape becoming too thick and difficult to pull. In this specification, "thickness of the first substrate layer" refers to the average value of the thicknesses of any five points in the first substrate layer, measured using the TH-104 paper and film thickness measuring instrument (manufactured by Tester Sangyo Co., Ltd.).

[0018] There are no particular restrictions on the ratio of the thickness of the first adhesive layer to the thickness of the first substrate layer, and it can be appropriately selected according to the purpose. However, the ratio of the thickness of the adhesive layer to the thickness of the first substrate layer, expressed as [thickness of the first adhesive layer / thickness of the first substrate layer], is preferably 1 / 5 to 5 / 1, more preferably 1 / 3 to 3 / 1, and even more preferably 1 / 2 to 2 / 1. When the ratio of the thickness of the first adhesive layer to the thickness of the first substrate layer is within this preferred range, excellent adhesion and re-peelability (ease of removal) of the adhesive tape can be obtained. On the other hand, if the ratio is greater than 5 / 1, there is a possibility that only the first adhesive layer will remain on the adherend during the re-peeling process of the adhesive tape. Also, if the ratio is less than 1 / 5, there is a concern that the adhesive strength will decrease if the surface of the adherend has an uneven shape, for example, because the first adhesive layer will not be able to follow the shape.

[0019] <<Material for first base material>> The stress of the first base layer at 25% elongation is preferably 0.15 MPa to 82 MPa, more preferably 0.15 MPa to 10 MPa, even more preferably 0.15 MPa to 5 MPa, and most preferably 0.15 MPa to 4.5 MPa. When the stress of the first base layer at 25% elongation is 0.15 MPa to 82 MPa, suitable adhesive strength for the first base layer can be obtained, and it can be peeled off relatively easily even when elongation peeling occurs. On the other hand, if the stress of the first base layer at 25% elongation is less than 0.15 MPa, it is difficult to obtain non-adhesion force at the interface between the first adhesive layer and the first base layer, which may impair the holding power of the adhesive tape, for example. Also, if the stress of the adhesive tape at 25% elongation exceeds 82 MPa, the force required to elongate the adhesive tape when peeling it off tends to become excessive. The stress of the first base layer at 25% elongation refers to the stress value measured when the adhesive tape, punched out in a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, is stretched 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, and elongated by 25%. The first substrate material is not particularly limited as long as a first substrate layer having the above-mentioned specific physical properties can be obtained. Examples include styrene resins, which are copolymers and / or hydrogenated products thereof containing blocks mainly composed of styrene compound units and blocks mainly composed of conjugated diene units; polyurethane resins such as ester polyurethanes and ether polyurethanes; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; polycarbonate; polymethylpentene; polysulfone; polyetheretherketone; polyethersulfone; polyetherimide; polyimide film; fluororesin; nylon; and acrylic resin. These may be used individually or in combination of two or more, but it is preferable to use two or more in combination. Among these, styrene-based resins and polyurethane resins are preferred because they easily provide suitable tensile strength and elongation at break, with styrene-based resins being more preferred, and combinations of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, or hydrogenated styrene-isoprene-butadiene-styrene copolymer being particularly preferred.

[0020] -Styrene resin- Because styrene-based resins are thermoplastic resins, they exhibit excellent moldability in processes such as extrusion molding and injection molding, making it easy to form the first base layer. Furthermore, styrene-based resins generally exhibit particularly excellent elongation at break among the group of resins called thermoplastic resins, making them suitable for use as the first base layer of adhesive sheets.

[0021] Therefore, in the first base material, the proportion of styrene-based resin to the total resin components is preferably 50% to 100%, more preferably 60% to 100%, even more preferably 65% ​​to 100%, and particularly preferably 70% to 100%. By having the proportion of styrene-based resin within the above preferred range, a first base layer with excellent elongation at break and tensile strength can be obtained.

[0022] Here, the styrene-based resin is a copolymer and / or a hydrogenated thereof containing a block mainly composed of styrene-based compound units (hereinafter also referred to as polymer block (A)) and a block mainly composed of conjugated diene units (also referred to as polymer block (B)). Examples of styrene-based compounds include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, diphenylethylene, 1-vinylnaphthalene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, and 4-(phenylbutyl)styrene. These may be used individually or in combination of two or more. Among these, styrene, α-methylstyrene, and mixtures thereof are preferred from the viewpoint of manufacturing cost and balance of physical properties, with styrene being more preferred. Furthermore, while not limited to the following, examples of conjugated dienes include 1,3-butadiene, 2-methyl-1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 1,3-hexadiene. Among these, 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene) are preferred from the viewpoint of versatility. These may be used individually or in combination of two or more.

[0023] Examples of styrene-based resins include, for example, styrene-isoprene copolymers, styrene-isoprene-styrene copolymers, styrene-isoprene-butadiene-styrene copolymers, styrene-butadiene-styrene copolymers, styrene-ethylene-butylene copolymers, styrene-ethylene-butylene-styrene copolymers, styrene-ethylene-propylene copolymers, styrene-ethylene-propylene-styrene copolymers, and hydrogenated versions thereof.

[0024] Polymer block (A) mainly consists of styrene-based compound units. "Mainly consists of" here means that polymer block (A) contains 50% by mass or more of styrene-based compound units based on its total mass. The content of styrene-based compound units in polymer block (A) is more preferably 70% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may be substantially 100% by mass, based on the total mass of polymer block (A). However, unless it interferes with the objectives and effects of the present invention, polymer block (A) may contain structural units derived from unsaturated monomers other than styrene compounds (hereinafter abbreviated as "other unsaturated monomer units") in a proportion of 10% by mass or less. Examples of such other unsaturated monomers include at least one selected from the group consisting of butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-pentadiene, 1,3-hexadiene, isobutylene, methyl methacrylate, methyl vinyl ether, N-vinylcarbazole, β-pinene, 8,9-p-menthene, dipentene, methylenenorbornene, 2-methylenetetrahydrofuran, etc. When polymer block (A) contains such other unsaturated monomer units, the bonding configuration is not particularly limited and may be random or tapered.

[0025] A styrene-based resin only needs to have at least one of the polymer blocks (A) described above. If a styrene-based resin set has two or more polymer blocks (A), these polymer blocks (A) may be identical or different. In this specification, "different polymer blocks" means that at least one of the monomer units constituting the polymer block, weight-average molecular weight, molecular weight distribution, stereoregularity, and, if there are multiple monomer units, the ratio of each monomer unit and the copolymerization form (random, gradient, block) is different.

[0026] Polymer block (B) mainly consists of conjugated diene units. Here, "mainly consists of" means that polymer block (B) contains 50% by mass or more of structural units based on its total mass. The content of structural units derived from conjugated dienes in polymer block (B) is more preferably 70% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may be substantially 100% by mass, based on the total mass of polymer block (B).

[0027] As long as polymer blocks (A) and polymer block (B) are bonded together, the bonding structure of the styrene-based resin is not limited and can be linear, branched, polybranched, radial, or a combination of two or more of these bonding patterns. Styrene-based resins rich in linear structures can provide excellent elongation at break to the first substrate layer. On the other hand, those with branched or polybranched structures but with styrene blocks at the molecular ends can adopt a pseudo-crosslinked structure and provide excellent cohesive force. For this reason, it is preferable to mix and use styrene-based resins according to the required mechanical properties. In particular, the bonding form between polymer block (A) and polymer block (B) is preferably linear. Examples include diblock copolymers represented as AB, triblock copolymers represented as ABA, tetrablock copolymers represented as ABAB, pentablock copolymers represented as ABABA, and (AB)nX type copolymers (where X represents a coupling agent residue and n represents an integer of 3 or more). Among these, linear triblock copolymers or diblock copolymers are preferred, and ABA type triblock copolymers are preferred. In this specification, when identical polymer blocks are linearly linked via a bifunctional coupling agent, the entire linked polymer block is treated as a single polymer block. Accordingly, polymer blocks that should strictly be written as YXY (where X represents a coupling residue), including the examples above, are represented as Y as a whole, unless it is necessary to distinguish them from a single polymer block Y. In this specification, polymer blocks of this type containing coupling agent residues are treated as described above. For example, a block copolymer containing coupling agent residues that should strictly be written as ABXBA (where X represents a coupling agent residue) is represented as ABA and treated as an example of a triblock copolymer.

[0028] Furthermore, the styrene resin may contain polymer blocks (C) made of other polymerizable monomers other than polymer blocks (A) and polymer block (B), as long as the objectives of the present invention are not impaired. In this case, when polymer block (C) is represented by C, examples of block copolymer structures include ABC-type triblock copolymers, ABCA-type tetrablock copolymers, ABAC-type tetrablock copolymers, and the like.

[0029] As for the styrene-based resin, it is preferable to use one in which the styrene-based compound units represented by the following general formula (1), etc., are present in a range of 5% to 75% by mass, more preferably in a range of 5% to 50% by mass, even more preferably in a range of 10% to 45% by mass, and particularly preferably in a range of 10% to 40% by mass, relative to the total mass of the styrene-based resin. When the ratio of styrene-based compound units to the total mass of the styrene-based resin is within the above preferred range, it becomes easier to obtain fracture elongation and fracture strength within a preferred range. [ka]

[0030] The styrene resin may have one or more functional groups such as carboxyl groups, hydroxyl groups, acid anhydride groups, amino groups, and epoxy groups in its molecular chain and / or at its molecular ends, as long as it does not impair the purpose and effects of the present invention, or it may not have any functional groups.

[0031] Here, when using a combination of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer as the styrene-based resin, the content of styrene-isoprene copolymer relative to the total mass of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer is preferably 0% to 80% by mass, more preferably in the range of 0% to 70% by mass, even more preferably in the range of 0% to 50% by mass, and particularly preferably in the range of 0% to 30% by mass. When the content of styrene-isoprene copolymer is within the above preferred range, it is possible to achieve both excellent elongation at break and tensile strength while also maintaining thermal durability.

[0032] Furthermore, it is preferable to use a styrene-isoprene copolymer whose weight-average molecular weight, measured using gel permeation chromatography (GPC) on a standard polystyrene basis, is 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. Having the weight-average molecular weight of the styrene-isoprene copolymer within this preferred range ensures good heat fluidity and compatibility during solvent dilution, thus allowing for the production of a first substrate layer with good workability in the manufacturing process while also possessing heat resistance, which is preferable.

[0033] Here, the weight-average molecular weight is measured using the GPC method, and the value is equivalent to that of standard polystyrene, measured using a GPC instrument (SC-8020, manufactured by Tosoh Corporation). The measurement conditions are as follows. -Measurement conditions- • Sample concentration: 0.5% by mass (tetrahydrofuran solution) • Sample injection volume: 100 μL • Eluent: THF (tetrahydrofuran) · Flow rate: 1.0mL / min · Measurement temperature: 40℃ • This column: TSKgel(registered trademark) GMHHR-H(20) 2 bottles • Guard column: TSKgel HXL-H • Detector: Differential refractometer • Standard polystyrene molecular weight: 10,000 to 20,000,000 (manufactured by Tosoh Corporation)

[0034] There are no particular limitations on the method for producing styrene-isoprene copolymers, styrene-isoprene-styrene copolymers, and mixtures of styrene-isoprene copolymers and styrene-isoprene-styrene copolymers. A conventionally known production method can be appropriately selected, and the copolymers can be obtained by obtaining block copolymers by anionic living polymerization and, if necessary, adding a coupling agent and reacting them. Specifically, there are no particular restrictions on the method for producing the styrene-isoprene copolymer, and any conventionally known production method can be appropriately selected. For example, a method in which styrene blocks and isoprene blocks are sequentially polymerized by anionic living polymerization can be used.

[0035] There are no particular limitations on the method for producing the styrene-isoprene-styrene copolymer, and any conventionally known production method can be appropriately selected. Examples include a method of sequentially polymerizing a styrene block and an isoprene block by an anionic living polymerization method, and a method of producing a block copolymer by first producing a block copolymer having living active ends and then reacting it with a coupling agent.

[0036] There are no particular limitations on the method for producing a mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, and a conventionally known production method can be appropriately selected. For example, a method of mixing the styrene-isoprene copolymer produced by the above method with the styrene-isoprene-styrene copolymer can be used.

[0037] Furthermore, as a method for producing a mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, it is also possible to produce the mixture simultaneously in a single polymerization step. In a more specific embodiment, using an anionic living polymerization method, firstly, styrene monomers are polymerized in a polymerization solvent using an anionic polymerization initiator to form a polystyrene block having living active ends. Secondly, isoprene is polymerized from the living active ends of the polystyrene block to obtain a styrene-isoprene block copolymer having living active ends. Thirdly, a portion of the styrene-isoprene block copolymer having living active ends is reacted with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. Fourthly, the remaining portion of the styrene-isoprene block copolymer having living active ends is deactivated using a polymerization inhibitor to form a styrene-isoprene block copolymer.

[0038] Here, the styrene-based resin is preferably a hydrogenated styrene-isoprene copolymer, a styrene-isoprene-styrene copolymer, a styrene-isoprene-butadiene-styrene copolymer, and a styrene-butadiene-styrene copolymer. More specifically, a hydrogenated copolymer is preferred, which is a block copolymer that has been hydrogenated and is composed of at least a polymer block (A) mainly consisting of styrene-based compound units and a polymer block (B) mainly consisting of structural units derived from isoprene (hereinafter also referred to as isoprene units), structural units derived from butadiene (hereinafter also referred to as butadiene units), or structural units derived from a mixture of isoprene and butadiene (hereinafter also referred to as isoprene and butadiene units).

[0039] When the styrene-based resin is a hydrogenated copolymer obtained by hydrogenating a block copolymer composed of at least a polymer block (A) and a polymer block (B) mainly composed of isoprene units, butadiene units, or isoprene and butadiene units, the polymer block (A) and polymer block (B) described above preferably have the following configurations.

[0040] Preferably, the weight-average molecular weight of at least one polymer block (A) in the styrene-based resin is 3,000 to 15,000, and more preferably 3,000 to 12,000. By having at least one polymer block (A) with a weight-average molecular weight within the above range, the mechanical strength of the styrene-based resin containing the styrene-based resin is further improved.

[0041] Furthermore, the total weight-average molecular weight of the polymer blocks (A) in the styrene-based resin is preferably 3,500 to 15,000, more preferably 4,500 to 15,000, even more preferably 4,500 to 12,000, particularly preferably 5,000 to 11,000, and most preferably 8,000 to 11,000, from the viewpoint of mechanical strength. Note that "weight-average molecular weight" is the weight-average molecular weight on a standard polystyrene basis, determined by the gel permeation chromatography (GPC) measurement described above. The weight-average molecular weight of each polymer block (A) in the styrene resin can be determined by measuring the sampled liquid each time polymerization of each polymer block is completed during the manufacturing process. Alternatively, in the case of a triblock copolymer having an ABA structure, for example, the weight-average molecular weight of the first polymer block A and polymer block B can be determined by the above method, and then subtracted from the weight-average molecular weight of the styrene resin to determine the weight-average molecular weight of the second polymer block A. Another method is to use the same method as the weight-average molecular weight of the total polymer block (A) in the case of a triblock copolymer having an ABA structure. 1The weight-average molecular weight of the second polymer block A can also be determined by calculating the total content of polymer block (A) confirmed by H-NMR measurement, then calculating the weight-average molecular weight of the first deactivated polymer block A by GPC measurement, and subtracting this value.

[0042] The styrene resin preferably contains polymer blocks (A) (or the total content of polymer blocks (A) if there are multiple polymer blocks (A)) at a ratio of 5 to 75% by mass, more preferably 5 to 50% by mass, and even more preferably 10 to 40% by mass, relative to the total amount of styrene resin. When the polymer block (A) content is within the above range, the resulting styrene resin exhibits superior flexibility. Furthermore, the content of polymer blocks (A) in styrene resins is: 1 This value was obtained using 1H NMR spectroscopy.

[0043] Polymer block (B) mainly consists of isoprene units, butadiene units, or isoprene and butadiene units. Here, polymer block (B) may contain other monomers as described above, and polymer block (B) may also contain structural units derived from conjugated diene compounds other than isoprene and butadiene, such as at least one selected from 2,3-dimethylbutadiene, 1,3-pentadiene, 1,3-hexadiene, etc. As described above, polymer block (B) mainly consists of isoprene units, butadiene units, or isoprene and butadiene units. Using butadiene units, or isoprene and butadiene units, is preferable because it provides excellent mechanical strength (especially rubber elasticity) for the styrene resin. Furthermore, it is even more preferable that it is mainly composed of isoprene and butadiene units. The mixing ratio of isoprene and butadiene is not particularly limited, but from the viewpoint of improving various performances, a molar ratio of isoprene / butadiene = 10 / 90 to 90 / 10 is preferred, 30 / 70 to 70 / 30 is more preferred, and 40 / 60 to 60 / 40 is even more preferred. In addition, when polymer block (B) is mainly composed of isoprene and butadiene units, there are no particular restrictions on their bonding configuration, and it can consist of random, tapered, perfectly alternating, partially block-like, block, or a combination of two or more of these.

[0044] The bonding configurations of isoprene and butadiene constituting the polymer block (B) can be 1,2-bonds and 1,4-bonds in the case of butadiene, and 1,2-bonds, 3,4-bonds and 1,4-bonds in the case of isoprene. In styrene-based resins, the total content of 1,2-bonds and 3,4-bonds in the polymer block (B) is preferably 40 mol% or more, more preferably 60 mol% or more, even more preferably 80 mol% or more, even more preferably 85 mol% or more, and most preferably 90 mol% or more. It is also preferable that it be 95 mol% or less. Furthermore, if polymer block (B) consists solely of butadiene, the above-mentioned "total content of 1,2-bonds and 3,4-bonds" shall be read as "content of 1,2-bonds" and applied accordingly. The content of 1,2-bonds and 3,4-bonds is: 1 This value was calculated by 1H-NMR measurement. In this specification, if polymer block (B) contains isoprene units, the sum of the 1,2-bonds and 3,4-bonds is referred to as the vinyl bond amount, and if polymer block (B) consists of butadiene units, the 1,2-bond amount is sometimes referred to as the vinyl bond amount.

[0045] Polymer block (B) may contain structural units derived from polymerizable monomers other than isoprene units and butadiene units, usually preferably 30% by mass or less, more preferably 10% by mass or less, based on the total mass of polymer block (B), as long as it does not hinder the objectives and effects of the present invention. Examples of such other polymerizable monomers include aromatic vinyl compounds such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, pt-butylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, and vinylanthracene, as well as at least one compound selected from the group consisting of methyl methacrylate, methyl vinyl ether, N-vinylcarbazole, β-pinene, 8,9-p-menthene, dipentene, methylenenorbornene, and 2-methylenetetrahydrofuran. When polymer block (B) contains structural units derived from monomers of polymers other than isoprene units and butadiene units, the bonding configuration is not particularly limited and may be random or tapered.

[0046] A styrene-based resin only needs to have at least one of the polymer blocks (B) described above. If a styrene-based resin has two or more polymer blocks (B), these polymer blocks (B) may be the same or different.

[0047] Furthermore, the hydrogenation rate of polymer block (B) is preferably 50 mol% or more, more preferably 75 mol% or more, and even more preferably 95 mol% or more. The above hydrogenation rate is determined by the amount of carbon-carbon double bonds in the structural units derived from the conjugated diene compound in polymer (B). 1 The values ​​were calculated using 1H-NMR spectroscopy, and the more detailed conditions are as described in the examples.

[0048] When the styrene resin is the hydrogenated copolymer described above, the weight-average molecular weight of the styrene resin is preferably 50,000 to 500,000, more preferably 60,000 to 400,000, even more preferably 65,000 to 300,000, and particularly preferably 70,000 to 115,000.

[0049] The fluidity of styrene resins is preferably such that the melt flow rate measured at 230°C and 21.6N is 0.01 to 300 g / 10 min. When forming films using the T-die method or inflation method, it is more preferably 0.01 to 100 g / 10 min, and when forming tubes or injection molding using the extrusion method, it is more preferably 0.1 to 100 g / 10 min. All "melt flow rates" in this specification are values ​​measured in accordance with JIS K 7210 (1999).

[0050] In the first embodiment, if the styrene-based resin is the hydrogenated copolymer described above, the styrene-based resin includes a hydrogenated block copolymer, styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS). The styrene-ethylene-ethylene / propylene-styrene block copolymer is a hydrogenated product of a block copolymer formed from styrene-butadiene-isoprene-styrene. Commercially available SEEPS can be used, for example, Septon 4033, Septon 4044, Septon 4055, Septon 4077, and Septon 4099 manufactured by Kuraray Co., Ltd.

[0051] Styrene resins can be produced by solution polymerization, emulsion polymerization, or solid-phase polymerization. Among these, solution polymerization is preferred, and known methods such as ionic polymerization (anionic polymerization, cationic polymerization, etc.) and radical polymerization can be applied. Among these, anionic polymerization is preferred. In anionic polymerization, aromatic vinyl compounds and conjugated diene compounds are sequentially added in the presence of a solvent, an anionic polymerization initiator, and optionally a Lewis base to obtain a block copolymer, a coupling agent is added as needed to cause a reaction, and then the block copolymer is hydrogenated to obtain a styrene resin.

[0052] Examples of organolithium compounds that can be used as polymerization initiators in the above method include methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, and pentyllithium. Examples of dilithium compounds that can be used as polymerization initiators include naphthalenedithium and dilithiohexylbenzene.

[0053] Examples of coupling agents include dichloromethane, dibromomethane, dichloroethane, dibromoethane, dibromobenzene, and phenyl benzoate. The amounts of these polymerization initiators and coupling agents used are appropriately determined based on the desired weight-average molecular weight of the target styrene resin. Typically, initiators such as alkyllithium compounds and dilithium compounds are used in a ratio of 0.01 to 0.2 parts by mass per 100 parts by mass of the total monomers such as the styrene compound, butadiene, and isoprene used in polymerization. When coupling agents are used, they are preferably used in a ratio of 0.001 to 0.8 parts by mass per 100 parts by mass of the total monomers.

[0054] The solvent is not particularly limited as long as it does not adversely affect the anionic polymerization reaction. Examples include aliphatic hydrocarbons such as cyclohexane, methylcyclohexane, n-hexane, and n-pentane; and aromatic hydrocarbons such as benzene, toluene, and xylene. The polymerization reaction is usually carried out at a temperature of 0 to 100°C, preferably 10 to 70°C, for 0.5 to 50 hours, preferably 1 to 30 hours.

[0055] During the above-mentioned anionic polymerization, the amount of 1,2-bonds and 3,4-bonds in the unhydrogenated block copolymer can be increased by adding an organic Lewis base, and the amount of 1,2-bonds and 3,4-bonds can be controlled by the amount of the organic Lewis base added. Examples of organic Lewis bases that can be used include amines such as triethylamine, N,N,N',N'-tetramethylethylenediamine (TMEDA), and N-methylmorpholine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; amides such as dimethylacetamide; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran (THF), and dioxane; glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; sulfoxides such as dimethyl sulfoxide; and ketones such as acetone and methyl ethyl ketone. These organic Lewis bases can be used individually or in combination of two or more. The amount of organic Lewis base added is determined by how much the amount of vinyl bonds in the isoprene units and / or butadiene units constituting the polymer block (B) is controlled. Therefore, there is no strict limit on the amount of Lewis base added, but it is generally preferable to use an amount of 0.1 to 1,000 moles, preferably 1 to 100 moles, per gram of lithium atom contained in the alkyllithium compound or dilithium compound used as a polymerization initiator.

[0056] After polymerization is carried out by the method described above, the polymerization reaction is stopped by adding active hydrogen compounds such as alcohols, carboxylic acids, and water, and a hydrogenation reaction is carried out in an inert organic solvent in the presence of a hydrogenation catalyst. The hydrogenation reaction can be carried out with a hydrogen pressure of 0.1 to 20 MPa, preferably 0.5 to 15 MPa, more preferably 0.5 to 5 MPa, a reaction temperature of 20 to 250°C, preferably 50 to 180°C, more preferably 70 to 180°C, and a reaction time of usually 0.1 to 100 hours, preferably 1 to 50 hours. Examples of hydrogenation catalysts include Raney nickel; heterogeneous catalysts in which metals such as Pt, Pd, Ru, Rh, and Ni are supported on elements such as carbon, alumina, and diatomaceous earth; Ziegler catalysts consisting of combinations of transition metal compounds with alkylaluminum compounds, alkyllithium compounds, etc.; and metallocene catalysts.

[0057] The styrene resin obtained in this manner can be acquired by solidifying the polymerization reaction solution by pouring it into methanol or the like, then heating or drying under reduced pressure, or by performing so-called steam stripping, in which the polymerization reaction solution is poured into hot water with steam and the solvent is removed by azeotropic removal, followed by heating or drying under reduced pressure.

[0058] -Polyurethane resin- There are no particular restrictions on the polyurethane resin, and it can be appropriately selected according to the purpose, but it is preferable to have a softening point of 40°C or higher, and more preferably one with a softening point of 50°C or higher. Furthermore, it is preferable that the upper limit of the softening point be 100°C or lower. The softening point refers to the value measured in accordance with JIS K 2207 (ring ball method) (the same applies to the softening point hereafter).

[0059] As the polyurethane resin, a reaction product of polyol (b1-1) and polyisocyanate (b1-2) can be suitably used.

[0060] There are no particular restrictions on the polyol (b1-1), and it can be appropriately selected depending on the purpose. Examples include polyester polyol, polyether polyol, polycarbonate polyol, and acrylic polyol. These may be used individually or in combination of two or more. Among these, polyester polyol and polyether polyol are preferred as polyol (b1-1) because they allow for obtaining the mechanical properties of the first base material layer. When heat resistance is required in the first base material layer, polyester polyol is preferred, and when water resistance or biodegradability is required, polyether polyol is preferred.

[0061] Examples of polyester polyols include polyesters obtained by esterifying a low molecular weight polyol with a polycarboxylic acid, polyesters obtained by ring-opening polymerization of cyclic ester compounds such as ε-caprolactone, and copolymer polyesters thereof.

[0062] Examples of low molecular weight polyols that can be used in the production of 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, and cyclohexanedimethanol, all of which generally have a weight-average molecular weight of around 50 to 300.

[0063] Examples of polycarboxylic acids 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 their anhydrides or esterified products.

[0064] Examples of polyether polyols include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as initiators.

[0065] As the polycarbonate polyol, for example, one obtained by reacting a carbonate ester and / or phosgene with a low molecular weight polyol, as described later, can be used.

[0066] Examples of carbonate esters include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, and diphenyl carbonate.

[0067] Examples of low molecular weight polyols that can react with carbonate esters and / or phosgene and can be used in the production of polycarbonate polyols 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, 1 Examples include ,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.

[0068] There are no particular restrictions on the polyisocyanates (b1-2), and they can be appropriately selected depending on the purpose. For example, alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, etc., can be used, with alicyclic polyisocyanates being a prime example. These may be used individually or in combination of two or more.

[0069] Examples of alicyclic polyisocyanates include isophorone diisocyanate, 1,3-bis(isocyanate methyl)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, and bicycloheptane triisocyanate. These may be used individually or in combination of two or more.

[0070] There are no particular limitations on the method for producing polyurethane resin (b1) by reacting polyol (b1-1) and polyisocyanate (b1-2), and a conventionally known production method can be appropriately selected. For example, one method involves heating the polyol (b1-1) placed in a reaction vessel under atmospheric pressure or reduced pressure to remove moisture, and then supplying the polyisocyanate (b1-2) all at once or in portions to react.

[0071] The reaction between polyol (b1-1) and polyisocyanate (b1-2) is preferably carried out in a range of 1.0 to 20.0, more preferably in a range of 1.1 to 13.0, even more preferably in a range of 1.2 to 5.0, and particularly preferably in a range of 1.5 to 3.0.

[0072] There are no particular restrictions on the reaction conditions between the polyol (b1-1) and polyisocyanate (b1-2). These conditions can be appropriately selected considering various factors such as safety, quality, and cost. However, a reaction temperature of 70°C to 120°C and a reaction time of 30 minutes to 5 hours are preferred.

[0073] When reacting polyol (b1-1) with polyisocyanate (b1-2), catalysts such as tertiary amine catalysts and organometallic catalysts can be used as needed.

[0074] Furthermore, the above reaction may be carried out in a solvent-free environment or in the presence of an organic solvent. There are no particular restrictions on the organic solvent, and it can be appropriately selected depending on the purpose. Examples 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 individually or in combination of two or more. Organic solvents may be removed during or after the production of polyurethane resin (b1) by appropriate methods such as reduced-pressure heating or atmospheric-pressure drying.

[0075] -Other ingredients- Other components in the first substrate layer are not particularly limited and can be appropriately selected within a range that does not impair the properties of the adhesive tape. Examples include: tackifying resin; polymer components other than the material for the first substrate; additives such as crosslinking agents, anti-aging agents, UV absorbers, fillers, polymerization inhibitors, surface modifiers, antistatic agents, defoamers, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, silica beads, organic beads, etc.; and inorganic fillers such as silicon dioxide, aluminum oxide, titanium dioxide, zirconia, and antimony pentoxide. These may be used individually or in combination of two or more. The content of other components in the first base layer can be appropriately selected within a range that does not impair the properties of the adhesive tape.

[0076] The tackifying resin can be used to improve the adhesion between the adhesive layer of the adhesive tape and the first substrate layer, and to improve its heat resistance.

[0077] There are no particular restrictions on the tackifying resin, and it can be appropriately selected according to the purpose, but it is preferable that it has a softening point of 80°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, and particularly preferably 110°C or higher.

[0078] As the tackifying resin, for example, those described in the section "-Rubber-based adhesive resin-" below can be used, and the preferred embodiments are the same.

[0079] There are no particular restrictions on the anti-aging agent, and any known agent can be appropriately selected according to the purpose. Examples include phenolic anti-aging agents, phosphorus-based anti-aging agents (sometimes referred to as "processing stabilizers"), amine-based anti-aging agents, and imidazole-based anti-aging agents. These may be used individually or in combination of two or more. Among these, phenolic anti-aging agents and phosphorus-based anti-aging agents are preferred, and using them in combination is preferable because it can effectively improve the heat stability of the first substrate material, resulting in an adhesive tape that maintains good initial adhesion and has even better heat durability. Note that phosphorus-based anti-aging agents may slightly discolor (yellowing) over time in high-temperature environments, so it is preferable to appropriately set the amount used, taking into consideration the balance between initial adhesion, heat durability, and discoloration prevention.

[0080] Generally, phenolic compounds with sterically hindered groups can be used as phenolic antioxidants, with monophenol, bisphenol, and polyphenol types being typical examples. Specific examples include 2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), 4,4'-butylidenebis-(3-methyl-6-t-butylphenol), tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane, and n-octadecyl-3-(4'-hydroxy-3'5'-di-t-butylphenyl)propionate. These may be used individually or in combination of two or more.

[0081] There are no particular restrictions on the amount of phenolic antioxidant used, and it can be appropriately selected depending on the purpose. However, it is preferable to use it in the range of 0.1 to 5 parts by mass, and more preferably in the range of 0.5 to 3 parts by mass, per 100 parts by mass of the first base material. This effectively improves the heat resistance stability of the first base material, and as a result, an adhesive tape can be obtained that maintains good initial adhesion and has even better heat durability.

[0082] <Adhesive layer> In the first embodiment, the adhesive tape comprises a first adhesive layer and a third adhesive layer as adhesive layers. The first adhesive layer and the third adhesive layer are adhesive layers that form the adhesive surface of the adhesive tape that adheres to the object to be adhered. Each adhesive layer is formed by an adhesive composition containing an adhesive resin, and may also contain filler particles and other components as needed. Furthermore, each adhesive layer may consist of the same adhesive composition or each may consist of a different adhesive composition.

[0083] The characteristics of each adhesive layer in the first embodiment will be described below. The stress of the adhesive layer at 25% elongation is not particularly limited and can be appropriately selected depending on the purpose, but 0.04 MPa to 0.4 MPa is preferred, and 0.05 MPa to 0.1 MPa is more preferred. When the stress of the adhesive layer at 25% elongation is within the preferred range, suitable adhesive strength for the adhesive tape can be obtained, and it can be peeled off relatively easily even when elongation peeling occurs. On the other hand, if the stress of the adhesive layer at 25% elongation is less than 0.04 MPa, the adhesive tape may peel off when a load is applied in the shear direction to the adhesive tape, even though hard adherends are fixed together. If it exceeds 0.4 MPa, the force required to elongate the adhesive tape when peeling it off may become excessive. The 25% elongation stress of the adhesive layer refers to the stress value measured when the adhesive layer is punched out in a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled lengthwise at a tensile speed of 300 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 elongated by 25%.

[0084] There are no particular restrictions on the breaking strength of the adhesive layer, and it can be appropriately selected depending on the purpose, but 0.5 MPa to 2.1 MPa is preferred, and 1.0 MPa to 2.1 MPa is more preferred. When the breaking strength of the adhesive layer is within the above preferred range, it is possible to suppress the tearing of the adhesive tape when stretching and peeling it off, and the load required to stretch the adhesive tape does not become excessive, making it easier to peel off again by pulling. On the other hand, if the breaking strength of the adhesive layer is less than 0.5 MPa, adhesive residue may occur due to cohesive failure of the adhesive layer when stretching and peeling the adhesive tape, and if it exceeds 2.1 MPa, sufficient adhesion may not be obtained. The force required to stretch and deform the adhesive tape also depends on the thickness of the adhesive tape, and for example, even if you try to stretch and peel off an adhesive tape that is thick and has a high breaking strength, you may not be able to stretch it enough and therefore not be able to peel it off. The breaking strength of the adhesive layer in adhesive tape refers to the stress value measured when the adhesive layer is punched out in a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled lengthwise at a tensile speed of 300 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.

[0085] The elongation at break of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but 450% to 1,300% is preferred, 500% to 1,200% is more preferred, and 600% to 1,100% is even more preferred. By having the elongation at break of the adhesive layer within the above preferred range, it is possible to achieve both good adhesion and re-peelability (ease of removal). The elongation at break of the adhesive layer in adhesive tape refers to the tensile elongation measured when the adhesive layer is punched out in a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled lengthwise at a tensile speed of 300 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.

[0086] There are no particular restrictions on the thickness of the adhesive layer, and it can be appropriately selected depending on the purpose, but it is preferably 5 μm to 150 μm, more preferably 20 μm to 120 μm, even more preferably 30 μm to 110 μm, and particularly preferably 50 μm to 100 μm. "Thickness of the adhesive layer" refers to the thickness of one adhesive layer in the adhesive tape. The average thickness of each adhesive layer may be the same or different from one another. In this specification, "thickness of the adhesive layer" refers to the average value of the thickness of the adhesive layer at any five points in the adhesive tape, measured using the TH-104 paper and film thickness measuring instrument (manufactured by Tester Sangyo Co., Ltd.).

[0087] In the first embodiment, the first adhesive layer is preferably 10 to 150 μm thick, more preferably 20 to 130 μm thick, and even more preferably 30 to 110 μm thick, as this facilitates adhesion to the adherend. The third adhesive layer is preferably 10 to 100 μm thick, and more preferably 30 to 80 μm thick, as this facilitates adhesion to the adherend. The second adhesive layer may have the same thickness as the first or third adhesive layer, or it may have a different thickness.

[0088] In the first embodiment, at least the third adhesive layer, preferably the adhesive layers on both sides adjacent to the foam layer (the second and third adhesive layers in the first embodiment, and the third and fourth adhesive layers in the second and third embodiments described later), has a peak value of loss tangent (tanδ) at a frequency of 1 Hz preferably between -30°C and 0°C, and more preferably between -20°C and -5°C. Setting the peak value of the loss tangent of the adhesive layer within this range makes it easier to impart good adhesion to the adherend at room temperature. The loss tangent (tanδ) can be calculated from the storage modulus (G') and loss modulus (G'') obtained by dynamic viscoelasticity measurements using temperature dispersion, using the formula tanδ = G'' / G'. The peak value of the loss tangent (tanδ) at a certain frequency can be obtained from dynamic viscoelasticity measurements using temperature dispersion. The dynamic viscoelastic properties can be adjusted by appropriately selecting the type and ratio of monomers used in the copolymer constituting the adhesive resin, the type and amount of polymerization initiator used, the type and amount of crosslinking agent and tackifying resin used, the polymerization method, and so on.

[0089] The dynamic viscoelastic properties of the aforementioned adhesive layer are defined by the loss tangent of the dynamic viscoelastic spectrum, or the loss tangent and storage modulus, at a specific frequency and temperature. Furthermore, they are defined by the temperature at which the loss tangent of the dynamic viscoelastic spectrum at a specific frequency shows a peak, or by the peak value of the loss tangent. For the measurement of dynamic viscoelasticity, a viscoelasticity tester (manufactured by Rheometrics, trade name: Ares 2KSTD) is used. The test specimen is placed between the parallel discs that constitute the measuring section of the tester, and the storage modulus (G') and loss modulus (G'') are measured at a frequency of 1 Hz from -50°C to 150°C. The test specimen has an adhesive layer approximately 2 mm thick and is placed between the parallel discs for measurement.

[0090] - Filler particles -

[0091] In the first embodiment, the adhesive layer adjacent to the first base layer is preferably a first adhesive layer formed from an adhesive composition containing filler particles with an average particle size of 10 to 40 μm and an adhesive resin. Furthermore, the content of filler particles in the adhesive composition for forming the first adhesive layer containing filler particles is preferably 3 to 50 parts by mass per 100 parts by mass of adhesive resin. Similarly, the second adhesive layer adjacent to the first base layer is preferably formed from an adhesive composition containing filler particles with an average particle size of 10 to 40 μm and an adhesive resin. Furthermore, the content of filler particles in the second adhesive layer containing filler particles is preferably 3 to 50 parts by mass per 100 parts by mass of adhesive resin. Preferably, the adhesive layer adjacent to the first base layer is at least the first adhesive layer. Furthermore, if a second adhesive layer is provided between the first base layer and the foam layer as necessary, as in the adhesive tape of the second embodiment described later, the adhesive layer adjacent to the first base layer may be the first adhesive layer and the second adhesive layer described later. Moreover, in this specification, when simply referred to as an adhesive layer, the adhesive layer includes both the first adhesive layer and the second adhesive layer.

[0092] Because the adhesive layer or the adhesive composition forming the adhesive layer contains the filler particles, when the first base layer is stretched to peel the adhesive tape from between the first and second adherends, the adjacent adhesive layer also stretches in accordance with the first base layer, and the filler particles are exposed from the adhesive layer. As a result, the adhesive area between the first adhesive layer and the adherend is reduced. Therefore, the adhesive tape can be peeled off more easily, thus simplifying the peeling process. Alternatively, as in the adhesive tape of the second embodiment described later, if a second adhesive layer is provided between the first base material layer and the foam layer as needed, the adhesive area between the second adhesive layer and the layer adjacent to it (e.g., the foam layer) becomes smaller. Therefore, the adhesive tape can be peeled off more easily, further simplifying the peeling process.

[0093] There are no particular restrictions on the type of filler particles, and they can be appropriately selected within a range that does not impair the effects of the present invention. They may be inorganic filler particles or organic filler particles. These may be used individually or in combination of two or more types.

[0094] Specific examples of inorganic filler particles 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 carbonate-calcium, calcium carbonate, barium carbonate, Examples include molybdenum oxide, antimony oxide, red phosphorus, mica, clay, kaolin, talc, zeolite, wollastonite, smectite, silica (quartz, fumed silica, precipitated silica, anhydrous silicic acid, fused silica, crystalline silica, ultrafine amorphous silica, etc.), potassium titanate, magnesium sulfate, sepiolite, zonolite, aluminum borate, barium sulfate, barium titanate, zirconia oxide, cerium, tin, indium, carbon, sulfur, therium, cobalt, molybdenum, strontium, chromium, barium, lead, tin oxide, indium oxide, diamond, magnesium, platinum, zinc, manganese, and stainless steel. Among these, aluminum hydroxide and nickel are preferred. Furthermore, the inorganic filler may be subjected to surface treatments such as silane coupling treatment or stearic acid treatment to improve its dispersibility in the adhesive resin.

[0095] Specific examples of organic filler particles include polystyrene-based fillers, benzoguanamine-based fillers, polyethylene-based fillers, polypropylene-based fillers, silicone-based fillers, urea-formaldehyde-based fillers, styrene / methacrylic acid copolymers, fluorine-based fillers, acrylic-based fillers, polycarbonate-based fillers, polyurethane-based fillers, polyamide-based fillers, epoxy resin-based fillers, and thermosetting resin-based hollow fillers.

[0096] Furthermore, among organic filler particles, silicone-based fillers can be specifically silicone rubber particles formed by three-dimensionally crosslinking linear organopolysiloxanes (see Japanese Patent Publication No. 63-77942, Japanese Patent Publication No. 3-93834, and Japanese Patent Publication No. 04-198324), powdered silicone rubber (see U.S. Patent No. 3,843,601, Japanese Patent Publication No. 62-270660, and Japanese Patent Publication No. 59-96,122). Moreover, the surface of the silicone rubber particles obtained by the above method can be (R'SiO 3 / 2 ) n Silicone composite particles coated with a silicone resin, which is a polyorganosilsesquioxane cured product having a three-dimensional network-like crosslinked structure represented by (R' represents a substituted or unsubstituted monovalent hydrocarbon group) (see Japanese Patent Publication No. 7-196815), can also be used. More specifically, silicone composite particles in which the surface of silicone rubber particles is coated with silicone resin are more preferable. Such silicone-based fillers include Toray Dow Corning Silicone Co., Ltd., which sells products such as Torayfil E-500, Torayfil E-600, Torayfil E-601, and Torayfil E-850 under the above product names, and Shin-Etsu Chemical Co., Ltd., which sells products such as KMP-600, KMP-601, KMP-602, and KMP-605. Alternatively, acrylic-modified silicone can be used as another silicone-based filler.

[0097] The adhesive layer in this embodiment contains an adhesive resin and filler particles, and preferably contains an adhesive resin, an acrylic-modified silicone, and an optional component, microballoons, as described later. In this embodiment, the filler particles present in the adhesive layer, particularly the acrylic-modified silicone, exhibit high affinity to the coexisting adhesive resin, making it difficult to determine the acrylic-modified silicone content and whether or not acrylic modification is present from the adhesive tape. If it is difficult to determine the presence or absence of filler particles, particularly acrylic-modified silicone, and their content in the adhesive layer or adhesive composition in this embodiment, for example, as an alternative to defining the presence or content of filler particles, particularly acrylic-modified silicone, the frictional force of the outer surface of the adhesive layer in this embodiment may be in the range of 0.1 to 5.0 N. In other words, in this embodiment, a specific means of achieving a frictional force of 0.1 to 5.0 N on the outer surface of the adhesive layer is to provide an adhesive layer containing an adhesive resin and an acrylic-modified silicone.

[0098] The frictional force of the outer surface of the adhesive layer of the adhesive tape in this embodiment is preferably 0.1 to 5.0 N, preferably 0.3 to 4.0 N, and more preferably 0.5 to 3.0 N. In this embodiment, if the frictional force of the outer surface of the adhesive layer is within the above range, when the adhesive tape is pulled to peel it off the adherend, the frictional resistance of the adhesive tape on the adherend surface decreases, effectively reducing the adhesive force of the adhesive layer to the adherend and making it easier to peel off the adhesive tape. In this embodiment, the outer surface of the adhesive layer refers to the surface that adheres to the adherend, or in other words, the outermost surface of the adhesive layer that is opposite to the base material layer among the two opposing surfaces of the adhesive layer. In the adhesive tape of this embodiment, the frictional force of the outer surface of at least one of the multiple adhesive layers is 0.1 to 5.0 N. Furthermore, the frictional force of the outer surfaces of both adhesive layers provided on both sides of the base material layer may also be 0.1 to 5.0 N. As described above, the frictional force of the adhesive layer in this specification refers to the frictional force of the surface of the adhesive layer that is in contact with the adherend, and the frictional force of the adhesive layer is measured by the test method described in the example below for measuring frictional force. More specifically, the frictional force of the outer surface of the adhesive layer in this specification refers to the frictional force against cotton canvas at 23°C, and is preferably 0.1 to 5.0 N, more preferably 0.3 to 4.0 N, and even more preferably 0.5 to 3.0 N. In addition, the cotton canvas described in this specification is made of cotton and is No. 9 cotton canvas [(applied to old JIS L3102) raw yarn twist (warp 10 / 2, weft 10 / 3), density (warp 44 - 48 threads / inch, weft 33 - 37 threads / inch), weight 510 g / m 2 )], and the measurement atmosphere of the frictional force is a temperature of 23°C and a humidity of 50%.

[0099] In this embodiment, when the acrylic-modified silicone is present in the adhesive layer, the frictional force on the surface of the adhesive layer tends to be low. Also, when the frictional force of the adhesive layer is low, it has the effect that it is easy to slide and peel during 90° peeling. The frictional force of the adhesive layer described in this specification refers to the frictional force on the surface of the adhesive layer on the side contacting the adherend (other than the base material layer), and the frictional force of the adhesive layer is measured by the test method described in the measurement of the frictional force explained in the column of the examples described later.

[0100]

[0101]

Chemical formula

[0102] (In the above general formula (2), R 1 and R 2 each independently represent 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 、X 3 、X 4 、X 5 、X 6 and X 1 each independently represent 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, and Y 2 and Y 1 each independently represent Xor -[O-Si(X 7 )(X 8 )] c -X 9 The group shown is X 7 , X 8 , and X 9 Each of these independently represents a substituted or unsubstituted C1-C20 alkyl group, a C6-C20 aryl group, a C1-C20 alkoxy group, 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 of the groups are hydroxyl groups, and a, b, and c are independently positive numbers satisfying 0 ≤ a ≤ 1,000, 100 ≤ b ≤ 10,000, and 1 ≤ c ≤ 1,000.

[0103] In general formula (2), R 1 or R 2 The C1-C20 alkyl group represented by may be linear, branched, or cyclic. Specifically, examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, cyclopentyl, cyclohexyl, and cycloheptyl groups. These alkyl groups may be substituted with halogen atoms, acryloxy, methacryloxy, carboxyl, alkoxy, alkenyloxy, amino, alkyl, alkoxy, or (meth)acryloxy-substituted amino groups. R 1 or R 2 Examples of aryl groups with 6 to 20 carbon atoms represented by R include phenyl groups, tolyl groups, and naphthyl groups. 1 or R 2 Preferably, it is a methyl group.

[0104] In general formula (2), X 1 ~X 9 The alkyl groups with 1 to 20 carbon atoms and the aryl groups with 6 to 20 carbon atoms represented by R are: 1 or R 2 Examples of groups similar to the alkyl and aryl groups exemplified above include the alkyl and aryl groups, respectively. X 1 ~X 9 Examples of alkoxy groups with 1 to 20 carbon atoms represented by θ include methoxy, ethoxy, propoxy, butoxy, hexyloxy, heptyloxy, octyloxy, decyloxy, and tetradecyloxy groups.

[0105] In general formula (2), a, b, and c are positive numbers between 0 ≤ a ≤ 1,000, 100 ≤ b ≤ 10,000, and 1 ≤ c ≤ 1,000, respectively, but a is preferably a positive number between 0 and 200. If a is greater than 1,000, the strength of the resulting film will be insufficient. b is preferably a positive number between 1,000 and 5,000. If b is less than 100, the flexibility of the film will be poor, and if it is greater than 10,000, it will be difficult to form a solid, granular structure. c is preferably a positive number between 1 and 200. Furthermore, the polyorganosiloxane represented by general formula (2) has at least two, preferably two to four, hydroxyl groups in one molecule from the standpoint of crosslinking, and it is preferable that these hydroxyl groups are located at both ends of the molecular chain.

[0106] Examples of acrylic acid ester monomers or methacrylic acid ester monomers used in the above-mentioned acrylic-modified silicones include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and cyclohexyl methacrylate.

[0107] 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.

[0108] The acrylic-modified silicone is preferably obtained by mixing 100 parts by mass of polyorganosiloxane represented by the general formula (2) above 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 thereto, and then performing emulsion graft polymerization. The conditions for emulsion graft polymerization are not particularly limited, and known radical initiators commonly used for acrylic polymers can be used as initiators during polymerization. In addition, known anionic surfactants and nonionic surfactants can be used as emulsifiers.

[0109] The acrylic-modified silicone usable in the adhesive composition of this embodiment may be any form containing a polymer in which a portion of the polyorganosiloxane is modified by a (meth)acrylic monomer, and is not particularly limited to solid, powder, particulate, or solution form. Furthermore, the shape of the acrylic-modified silicone usable in the adhesive composition of this embodiment is not particularly limited and can be appropriately selected according to the purpose, and may be regular or irregular in shape. Specific examples of granular acrylic-modified silicone include polygonal, cubic, elliptical, spherical, needle-shaped, plate-shaped, and flaky shapes, but among these, elliptical, spherical, and polygonal shapes are preferred, and spherical is more preferred. When the particle shape is elliptical, spherical, or polygonal, the adhesive layer slides well against the adherend when the adhesive tape is stretched, allowing the adhesive tape to be peeled off more easily and quickly. These particle shapes may be used individually or in combination of two or more. Furthermore, when granular acrylic-modified silicone is used, the average particle size of the acrylic-modified silicone is preferably 10 to 400 μm, and more preferably 15 to 400 μm. When granular acrylic-modified silicone is used in this embodiment, it is granulated and powdered by the following methods. These methods include spray drying and airflow drying, but a spray dryer is preferred in terms of productivity. Powdering is preferably done by hot drying, and the process is preferably carried out at 80 to 150°C. As silicone compounds that can be used in this embodiment, commercially available products such as Charine R-170, Charine R-170S, Charine R-770, Charine R-773, and Charine R-200 (all manufactured by Nisshin Chemical Industry Co., Ltd.) can also be used.

[0110] There are no particular restrictions on the particle size distribution (D90 / D10) of the filler particles added to the adhesive composition of this embodiment, and it can be appropriately selected according to the purpose, but 2.5 to 20 is preferred, 2.5 to 15 is more preferred in terms of impact resistance, and 2.5 to 5 is even more preferred. When the particle size distribution (D90 / D10) of the filler particles added to the adhesive composition is within a preferred range, the adhesive tape can be peeled off more easily and quickly, it is less likely to tear even when the thickness of the first substrate of the adhesive tape is thin, and it has excellent impact resistance, shear adhesion strength, and splitting adhesion strength. On the other hand, if the particle size distribution (D90 / D10) of the filler particles added to the adhesive composition is less than 2.5, the stretchable peelability may be impaired, and if it exceeds 20, the adhesive performance such as impact resistance, shear adhesion strength, and splitting adhesion strength may be impaired. The particle size distribution (D90 / D10) of filler particles added to an adhesive composition can be obtained, for example, by measuring the particle size of the filler particles using a measuring instrument (Microtrac) that employs laser diffraction scattering and converting it to a particle size distribution. Furthermore, "filler particles added to an adhesive composition" in this specification refers to the filler particles themselves when added to the adhesive composition, and is distinguished from filler particles present in the adhesive layer. More specifically, "average particle size" and "number-average primary particle diameter" in this specification are distinguished because their measurement methods differ. In this specification, "average particle size" refers to the volume-average particle diameter measured by laser diffraction scattering of individual filler particles. On the other hand, in this specification, "number-average primary particle diameter" refers to the number average of the primary particle diameter calculated from electron microscope images in an adhesive tape containing a mixture of one or more types of filler particles and / or microballoons.

[0111] The average particle size of the filler particles added to the adhesive composition is 5 to 40 μm, preferably 10 to 35 μm, more preferably 10 to 30 μm, and even more preferably 10 to 25 μm. When the average particle size of the filler particles is within this preferred range, the adhesive tape can be peeled off more easily and quickly, it is less likely to tear even when the thickness of the first substrate of the adhesive tape is thin, and it exhibits excellent impact resistance, shear adhesion, and splitting adhesion. On the other hand, if the average particle size of the filler particles is less than 5 μm, the stretchable peelability may be impaired, and if it exceeds 40 μm, the adhesive performance such as impact resistance, shear adhesion, and splitting adhesion may be impaired. The average particle size of filler particles refers to the volume-average particle size, which can be measured, for example, using a laser diffraction scattering method measuring instrument (Microtrac). Furthermore, the above average particle size includes not only primary particles but also aggregates of secondary particles and other materials.

[0112] Furthermore, when using the above-mentioned silicone rubber particles or silicone composite particles as filler particles added to the adhesive composition, the average particle size of the silicone rubber particles or silicone composite particles added to the adhesive composition is preferably 5 to 40 μm. If the average particle size is less than 5 μm, the effect of reducing the adhesive area by the filler particles when the adhesive tape is stretched tends to decrease, and if it is greater than 40 μm, the adhesive strength of the adhesive tape tends to decrease. Furthermore, when using the above-mentioned acrylic-modified silicone as filler particles, the average particle size of the acrylic-modified silicone is preferably 5 to 40 μm. If the average particle size is less than 5 μm, the effect of reducing the adhesive area by the filler particles when the adhesive tape is stretched tends to decrease, and if it is greater than 40 μm, the adhesive strength of the adhesive tape tends to decrease. On the other hand, in this embodiment, the number-average primary particle diameter of the filler particles present in the adhesive layer is 3 to 45 μm, preferably 5 to 42 μm, more preferably 8 to 40 μm, even more preferably 9 to 35 μm, and most preferably 10 to 32 μm. In this specification, "number-average primary mean particle diameter of filler particles" refers to the size of filler particles present in the adhesive layer, and the number-average primary mean particle diameter of filler particles present in the adhesive layer is measured using the following method. First, an adhesive tape cooled under liquid nitrogen was randomly cut in three places using a microtome, and three fragments were taken as samples. Then, a 400x magnification photograph was taken of each sample using a scanning electron microscope, and the filler particles, which are solid particles, were selected from the three photographs. Subsequently, the cross-sectional area of ​​the solid particles, calculated by binarization processing (e.g., Otsu's binarization process) using image analysis software, was considered as the area of ​​a circle, and the equivalent circle diameter of each solid particle was measured. Then, the total number of solid particles in the three photographs and the corresponding equivalent circle diameter were calculated, and the number-average primary mean particle diameter of the filler particles was calculated from the following formula (A).

number

[0113] There are no particular restrictions on the ratio of the average particle size of the filler particles to the average thickness of the adhesive layer containing the filler particles, and it can be appropriately selected depending on the purpose. However, it is preferable that the ratio of the primary average particle size of the filler particles to the average thickness of the adhesive layer, expressed as [primary average particle size of filler particles / average thickness of the adhesive layer], be 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. When the ratio is 5 / 100 or more, the adhesive tape can be peeled off more easily and quickly, and it is less likely to tear even when the thickness of the first base material of the adhesive tape is thin. Furthermore, when the ratio is 95 / 100 or less, it is advantageous in that the adhesive performance such as impact resistance, shear adhesive strength, and splitting adhesive strength is also superior.

[0114] The content of filler particles in the adhesive layer or the adhesive composition for forming the adhesive layer is 3 to 50 parts by mass per 100 parts by mass of adhesive resin, preferably 10 to 50 parts by mass, and more preferably 15 to 40 parts by mass. A filler particle content of 3 parts by mass or more per 100 parts by mass of adhesive resin allows for easier and quicker removal of the adhesive tape. Furthermore, a filler particle content of 50 parts by mass or less per 100 parts by mass of adhesive resin prevents the adhesive composition from remaining on the adherend, reduces impact resistance, and weakens shear and splitting adhesive strengths. The content of filler particles in the adhesive layer can be adjusted as appropriate when preparing the adhesive composition.

[0115] Furthermore, when using the above-mentioned silicone rubber particles or silicone composite particles as filler particles to be added to the adhesive composition, the content of the silicone rubber particles or silicone composite particles added to the adhesive composition is preferably 3 to 20 parts by mass per 100 parts by mass of the adhesive resin. Furthermore, when using the above-mentioned acrylic-modified silicone as filler particles to be added to the adhesive composition, the amount of acrylic-modified silicone added to the adhesive composition is preferably 10 to 50 parts by mass per 100 parts by mass of the adhesive resin.

[0116] The volume ratio of filler particles to the total volume of the adhesive layer is preferably 4-40%, more preferably 5-30%, even more preferably 5-20%, and most preferably 5-15%. A volume ratio of 4% or more of filler particles allows the adhesive tape to be removed more easily and quickly. Furthermore, a volume ratio of 40% or less of filler particles prevents adhesive composition from remaining on the adherend, reduces impact resistance, and weakens shear and splitting adhesive strengths. The volume ratio of filler particles to the adhesive layer can be calculated using the following formulas (1) to (3). Adhesive resin *1 Mass A(g) / adhesive resin *1 Density A (g / cm³) 3 ) = Volume A of adhesive resin*1 (cm³) 3 )...Equation (1) Mass of filler particles B (g) / Density of filler particles B (g / cm³) 3 ) = volume B of filler particles (cm³) 3 )...Equation (2) Volume B of filler particles (cm³) 3 ) / (Adhesive resin *1 Volume A(cm³) 3 ) + volume B (cm³) of filler particles 3 )) × 100 = Volume ratio of filler particles (%) ... Equation (3) Furthermore, in the above formulas (1) and (3), *1 The adhesive resin represented by may also contain other components described below. The density is a value measured in accordance with JIS Z 8804.

[0117] -Adhesive resin- The adhesive layer of this embodiment essentially contains an adhesive resin. There are no particular restrictions on the adhesive resin, and it can be appropriately selected from known ones, such as acrylic adhesive resins, rubber adhesive resins, urethane adhesive resins, silicone adhesive resins, or other adhesive resins. These may be used individually or in combination of two or more. Among these, it is preferable that the adhesive resin includes an acrylic adhesive resin.

[0118] --Acrylic adhesive resin-- There are no particular restrictions on the acrylic adhesive resin, and it can be appropriately selected depending on the purpose. Examples include acrylic polymers, and those containing additives such as tackifying resins and crosslinking agents as needed.

[0119] Acrylic polymers can be produced, for example, by polymerizing (meth)acrylate monomers. As the (meth)acrylate monomer mentioned above, for example, an alkyl (meth)acrylate having an alkyl group with 1 to 12 carbon atoms can be used. Specific examples of alkyl(meth)acrylates having an alkyl group with 1 to 12 carbon atoms include methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, t-butyl(meth)acrylate, n-hexyl(meth)acrylate, n-octyl(meth)acrylate, isooctyl(meth)acrylate, isononyl(meth)acrylate, cyclohexyl(meth)acrylate, and 2-ethylhexyl(meth)acrylate. These may be used individually or in combination of two or more.

[0120] As the alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms, it is preferable to use an alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms, more preferable to use an alkyl (meth)acrylate having an alkyl group having 4 to 8 carbon atoms, and it is particularly preferable to use n-butyl acrylate in order to ensure excellent adhesion to the adherend.

[0121] Alkyl (meth)acrylates having an alkyl group with 1 to 12 carbon atoms are preferably used in a range of 80 to 98.5% by mass, and more preferably in a range of 90 to 98.5% by mass, relative to the total amount of monomers used in the production of the acrylic polymer.

[0122] In addition to the monomers mentioned above, highly polar vinyl monomers can be used as monomers for the production of acrylic polymers, as needed. Examples of highly polar vinyl monomers include (meth)acrylic monomers such as (meth)acrylic monomers having hydroxyl groups, (meth)acrylic monomers having carboxyl groups, and (meth)acrylic monomers having amide groups; vinyl acetate; ethylene oxide-modified succinic acid acrylate; and sulfonic acid group-containing monomers such as 2-acrylamido-2-methylpropanesulfonic acid. These may be used individually or in combination of two or more.

[0123] Specific examples of vinyl monomers having hydroxyl groups include (meth)acrylic monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate.

[0124] It is preferable to use vinyl monomers having hydroxyl groups when using an adhesive resin that contains an isocyanate-based crosslinking agent. Specifically, it is preferable to use 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, or 6-hydroxyhexyl (meth)acrylate as vinyl monomers having hydroxyl groups.

[0125] The vinyl monomer having a hydroxyl group is preferably used in an amount of 0.01 to 1.0% by mass, and more preferably in an amount of 0.03 to 0.3% by mass, relative to the total amount of monomers used in the production of the acrylic polymer.

[0126] Specific examples of vinyl monomers having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, and (meth)acrylic monomers such as ethylene oxide-modified succinic acid acrylate. Among these, acrylic acid is preferred. Specific examples of vinyl having an amide group include N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, and (meth)acrylic monomers such as N,N-dimethylacrylamide.

[0127] The highly polar vinyl monomer is preferably used in an amount of 1.5% to 20% by mass, more preferably in an amount of 1.5% to 10% by mass, and even more preferably in an amount of 2% to 8% by mass, relative to the total amount of monomer used in the production of the acrylic polymer, as this allows for the formation of an adhesive layer with a balanced cohesive force, holding power, and adhesion.

[0128] There are no particular restrictions on the method for producing acrylic polymers, and any known method can be appropriately selected depending on the purpose. For example, methods include polymerizing monomers using polymerization methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. Among these, acrylic polymers are preferably produced by solution polymerization or bulk polymerization.

[0129] During polymerization, peroxide-based thermal polymerization initiators such as benzoyl peroxide and lauroyl peroxide, azo thermal polymerization initiators such as azobisisobutylnitrile, acetophenone-based photopolymerization initiators, benzoin ether-based photopolymerization initiators, benzyl ketal-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, benzoin-based photopolymerization initiators, and benzophenone-based photopolymerization initiators may be used as needed. In this embodiment, the acrylic polymer may be a homopolymer, a polypolymer (a binary to heptagonal copolymer), or a mixture thereof.

[0130] The weight-average molecular weight of the acrylic polymer obtained by the above method is preferably 300,000 to 3,000,000, and more preferably 500,000 to 2,500,000, as measured in terms of standard polystyrene using gel permeation chromatography (GPC).

[0131] Here, the weight-average molecular weight of the acrylic polymer is measured using the GPC method, and the value is equivalent to that of standard polystyrene, measured using a GPC instrument (HLC-8329GPC, manufactured by Tosoh Corporation). The measurement conditions are as follows. [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℃ • This column: TSKgel GMHHR-H (20) x 2 • Guard column: TSKgel HXL-H • Detector: Differential refractometer • Standard polystyrene molecular weight: 10,000 to 20,000,000 (manufactured by Tosoh Corporation)

[0132] In this embodiment, the acrylic polymer is preferably a triblock copolymer represented by the following general formula (I) or a diblock copolymer represented by the general formula (V) described later. The preferred embodiments of the acrylic polymer in this embodiment will be described below.

[0133] <Triblock copolymer> The adhesive layer of the adhesive tape of this embodiment is given by the following general formula (I): [ka] The material contains a triblock copolymer having a repeating unit represented by the above general formula (I), where A, B, and C each independently represent a repeating unit, A and C each independently represent an alkyl methacrylate monomer unit, B represents an alkyl acrylate monomer unit, p, q, and r each independently represent the degree of polymerization of each monomer unit, and A and C may be the same or different alkyl methacrylate monomer units having different chemical structures. In the above general formula (I), * represents a bond with another atom.

[0134] In the above general formula (I), A and C represent repeating units different from B, and represent alkyl methacrylate monomer units. Furthermore, A and C are independent of each other and may be the same alkyl methacrylate monomer unit, or they may be alkyl methacrylate monomer units having different chemical structures. In this specification, "alkyl methacrylate monomer unit" refers to a constituent unit derived from the alkyl methacrylate monomer when the alkyl methacrylate monomer is (co)polymerized or graft polymerized, i.e., a repeating unit derived from the methacrylate monomer. In the present invention, the alkyl methacrylate monomer unit is defined by the following general formula (II): [ka] (In the above general formula (II), R 3 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituents R4 The substituent R may be substituted, and 4 (where represents a halogen atom, an amino group, or a cyano group.)

[0135] In the above general formula (II), R 3 From the viewpoint of re-peelability and high load-holding capacity, alkyl groups having 1 to 12 carbon atoms are more preferred, and alkyl groups having 1 to 4 carbon atoms are even more preferred. 1 The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and from the viewpoint of adhesive strength, linear or branched is preferred, and linear is more preferred. Examples of the alkyl group having 1 to 12 carbon atoms include linear or branched alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, isopentyl group, hexyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group, as well as cyclic alkyl groups such as cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, and dicyclopentanyl group. Examples of alkyl groups having 1 to 4 carbon atoms include linear or branched alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, and t-butyl group, as well as cyclic alkyl groups such as cyclobutyl group. From the viewpoint of re-peelability and high load-holding capacity, the alkyl groups having 1 to 4 carbon atoms are preferably methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and t-butyl groups, with methyl being more preferred.

[0136] Preferred R in the above general formula (II) 3 is an alkyl group consisting of a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, or cyclobutyl group, and one or more hydrogen atoms in the alkyl group are substituents R 2 They may be substituted with (halogen atoms, amino groups, or cyano groups).

[0137] In this embodiment, the alkyl methacrylate monomer is not particularly limited, and examples 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 viewpoint of high load-holding capacity and disassembly.

[0138] In the above general formula (I), B represents a repeating unit different from A and C, and represents an alkyl acrylate monomer unit. In this specification, "alkyl acrylate monomer unit" refers to a constituent unit derived from an alkyl acrylate monomer when an alkyl acrylate monomer is (co)polymerized or graft polymerized, i.e., a repeating unit derived from an acrylate monomer. In the present invention, the alkyl acrylate monomer unit is given by the following general formula (III): [ka] (In the above general formula (III), R 5 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituents R 6 The substituent R may be substituted, and 4 (where represents a halogen atom, an amino group, or a cyano group.) Preferably, it is represented by .

[0139] In the above general formula (III), R 5 From the viewpoint of adhesion, alkyl groups having 1 to 12 carbon atoms are more preferred, and alkyl groups having 4 to 8 carbon atoms are even more preferred. The alkyl group may be linear, branched, or cyclic, and from the viewpoint of adhesion, linear or branched is preferred.

[0140] Furthermore, the examples of alkyl groups having 1 to 12 carbon atoms in the above general formula (III) are the same as the examples of alkyl groups having 1 to 12 carbon atoms in the above general formula (I).

[0141] Preferred R in the above general formula (III) 5 is an alkyl group of any of the following: n-butyl group, isobutyl group, t-butyl group, n-pentyl group, isopentyl group, hexyl group, octyl group, cyclohexyl group, cycloheptyl group, or cyclooctyl group, and one or more hydrogen atoms in the alkyl group are substituent R 6 They may be substituted with (halogen atoms, amino groups, or cyano groups).

[0142] In this embodiment, examples of alkyl acrylate monomers 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, n-butyl acrylate, 2-ethylhexyl acrylate, and copolymers thereof are preferred from the viewpoint of achieving both adhesive strength and re-peelability.

[0143] In the above general formula (I), 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 0.02 to 0.40, and more preferably 0.05 to 0.37. q / (p+q+r) is preferably 0.20 to 0.95, and more preferably 0.25 to 0.90. r / (p+q+r) is preferably 0.02 to 0.40, and more preferably 0.05 to 0.37.

[0144] In this embodiment, the triblock copolymer is defined by the following general formula (IV): [ka] (In the above general formula (IV), R 3 and R 7 each independently represent an alkyl group having 1 to 4 carbon atoms, and one or more hydrogen atoms in the alkyl group may be substituted with a substituent R 4 , and the substituent R 4 represents a halogen atom, an amino group, or a cyano group, R 5 represents an alkyl group having 4 to 8 carbon atoms, and one or more hydrogen atoms in the alkyl group may be substituted with a substituent R 6 , and the substituent R 6 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.) It preferably has a repeating unit represented by

[0145] In the above general formula (IV), R 1 can apply the same aspect as R 3 in the above general formula (II). In the above general formula (IV), R 5 can apply the same aspect as R 5 in the above general formula (III). In the above general formula (IV), R 7 can apply the same aspect as R 3 in the above general formula (II). Also, in the above general formula (IV), p, q, and r can apply the same aspect as p, q, and r in the above general formula (I). Furthermore, in the above general formula (IV), R 3 and R 7 may be the same or different.

[0146] In this embodiment, when the triblock copolymer is represented by the above general formula (IV), R 3 is preferably selected from the group consisting of linear or branched alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, and cyclobutyl group, and R 5It is preferably 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, an n-pentyl group, an isopentyl group, a hexyl group, an octyl group, a nonyl group, a decyl group, or an undecyl group, R 7 The group 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, and preferably has a p / (p+q+r) of 0.02 to 0.40, a q / (p+q+r) of 0.20 to 0.95, and a r / (p+q+r) of 0.02 to 0.40.

[0147] In the present invention, it is preferable that A and C in the general formula (I) of the triblock copolymer are the same. Specifically, if the triblock copolymer has repeating units represented by the general formula (IV) above, R 1 and R 5 Preferably, the two groups are the same, p / (p+q+r) is 0.02 to 0.40, q / (p+q+r) is 0.20 to 0.95, and r / (p+q+r) is 0.02 to 0.40. In a triblock copolymer having repeating units represented by the above general formula (I), when A and C are the same (ABA-type triblock copolymer), a higher elastic modulus can be secured, making it easier to secure adhesive strength with high load-holding capacity, excellent re-peelability over time, and superior storage stability.

[0148] --Molecular weight-- The triblock copolymer preferably has a weight-average molecular weight Mw of 50,000 to 300,000, and a number-average molecular weight Mn of 50,000 to 300,000. More preferably, the triblock copolymer has a weight-average molecular weight Mw of 100,000 to 250,000 and a number-average molecular weight Mn of 100,000 to 250,000, and even more preferably, the triblock copolymer has a weight-average molecular weight Mw of 130,000 to 230,000 and a number-average molecular weight Mn of 130,000 to 230,000. It is preferable from the viewpoint of adhesion, re-peelability, and high load-holding capacity if the weight-average molecular weight Mw of the triblock copolymer is within the above range, and it is also preferable from the viewpoint of adhesion, re-peelability, and high load-holding capacity if the number-average molecular weight Mn of the triblock copolymer is within the above range. Here, the weight-average molecular weight Mw and number-average molecular weight Mn of the triblock polymer are measured using a GPC instrument (HLC-8329GPC, manufactured by Tosoh Corporation) and are expressed as standard polystyrene equivalent values. The measurement conditions are as follows. -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℃ • This column: TSKgel GMHHR-H (20) x 2 • Guard column: TSKgel HXL-H • Detector: Differential refractometer • Standard polystyrene molecular weight: 10,000 to 20,000,000 (manufactured by Tosoh Corporation)

[0149] --stereoregularity-- The triblock copolymer and / or the partial structure (e.g., block) of the triblock copolymer preferably have stereoregularity (tacticity). Specifically, the triblock copolymer and / or the partial structure (e.g., block) of the triblock copolymer may have isotactic, syndiotactic, or atactic stereoregularity, or it may have multiple blocks having any of these stereoregularities.

[0150] A preferred form of the triblock copolymer is the one in general formula (I) -(A) p The syndiotacticity of the polymer block in the - section preferably shows a proportion of rr triplets of 65% or more, and more preferably a proportion of rr triplets of 75-95%. As a preferred form of the triblock copolymer, in the general formula (I), the syndiotacticity of the polymer block of the "-(C) r -" part preferably shows a ratio of rr triads of 65% or more, and more preferably the ratio of rr triads is 75 to 95%. As a preferred form of the triblock copolymer, the polymer block of the "-(B) q -" part in the general formula (I) preferably shows atacticity.

[0151] When the triblock copolymer has a polymer block of the "-(A) p -" part with a ratio of rr triads of 65% or more, it has the effect of good re-peeling property and holding power at high temperatures.

[0152] Generally, the syndiotacticity of a polymer is expressed by the ratio of the chains (triads) composed of three monomer units being rr. In this specification, it is calculated by NMR measurement of the polymer. Specifically, 13 Since the signal peaks representing the triad sequences in C-NMR differ depending on conditions such as the type of polymer, measurement solvent, or measurement temperature, it is necessary to identify and quantify the signals according to the conditions of each measurement. In this specification, measurements are performed at 50 °C on a sample dissolved in deuterated chloroform.

[0153] Preferred forms of the triblock copolymer include polymethyl methacrylate block - poly(n-butyl acrylate) block - polymethyl methacrylate, polyethyl methacrylate block - poly(n-butyl acrylate) block - polyethyl methacrylate, polypropyl methacrylate block - poly(n-butyl acrylate) block - polypropyl methacrylate, polymethyl methacrylate block - poly(t-butyl acrylate) block - polymethyl methacrylate, polymethyl methacrylate block - polypropyl acrylate block - polymethyl methacrylate, and the like.

[0154] The triblock copolymer preferably has an overall molecular weight distribution in the ratio of weight-average molecular weight to number-average molecular weight of 1.0 to 2.3, and more preferably in the range of 1.00 to 1.50.

[0155] In this embodiment, when A and C in general formula (I) are different repeating units, the "-(A)" contained in the molecule of the triblock copolymer p - Total weight of the polymer block in the "-(A)" section (the "-(A)" section) p The total weight of the polymer blocks in the "-" section is referred to as a. ) and "-(B) q - Total weight of the polymer block in the "-(B)" section (the "-(B)" section) q The total weight of the polymer block in the - section is referred to as b. The ratio of a to b is preferably in the range of 2 / 98 to 67 / 33, and more preferably in the range of 5 / 95 to 60 / 40, from the viewpoint of adhesive properties.

[0156] In this embodiment, when A and C in general formula (I) are different repeating units, the "-(C)" contained in the molecule of the triblock copolymer r - Total weight of the polymer block in the section (the said "-(C)" r The total weight of the polymer blocks in the "-" section is referred to as c. ) and "-(B) q From the viewpoint of adhesive properties, the ratio of the total weight of the polymer block in the - section to the mass ratio of c / b is preferably in the range of 2 / 98 to 67 / 33, and more preferably in the range of 5 / 95 to 60 / 40.

[0157] In this embodiment, when A and C in general formula (I) are the same repeating unit, the "-(A)" contained in the molecule of the triblock copolymer p -" polymer block and "-(C) r - Total weight of polymer blocks in section ("-(A)") p -" polymer block and "-(C) r The total weight of the polymer blocks in the "-" section is referred to as d. ) and "-(B) qThe ratio of the total weight of the polymer block in the - section (referred to as b) to the mass ratio of d / b is preferably in the range of 5 / 95 to 80 / 20, and more preferably in the range of 10 / 90 to 75 / 25, from the viewpoint of adhesive properties.

[0158] The triblock copolymer may, if necessary, be modified with functional groups such as hydroxyl groups, carboxyl groups, acid anhydride groups, amino groups, or trimethoxysilyl groups in the molecular side chains or at the molecular main chain ends, as long as the effects of the present invention are not impaired.

[0159] --Manufacturing method for triblock copolymer-- The method for producing the triblock copolymer is not particularly limited and can be appropriately selected from conventionally known production methods, such as a method of sequentially polymerizing the block copolymer by anionic living polymerization or cationic living polymerization. Furthermore, if the triblock copolymer has stereoregularity (e.g., syndiotacticity), known methods using organometallic complexes may be used.

[0160] One example of a method for producing the aforementioned triblock copolymer is a method in which, in an inert polymerization solvent, a polymerization initiator is used to sequentially polymerize the main component alkyl methacrylate monomer and the main component alkyl acrylate monomer and / or monomers mainly composed of alkyl methacrylate monomer, in order to achieve a desired block bonding sequence.

[0161] In this embodiment, one method for producing a triblock copolymer involves, firstly, polymerizing an alkyl methacrylate monomer in a polymerization solvent using a polymerization initiator, thereby producing a polyalkyl methacrylate block (general formula (I) "-(A) pSecondly, an alkyl acrylate monomer is polymerized from the living active end of the above alkyl methacrylate to form a binary block copolymer of alkyl methacrylate-alkyl acrylate having a living active end (corresponding to the "-(A)" portion in general formula (I)). p -(B) q Thirdly, a portion of the methacrylate-alkyl acrylate binary block copolymer having a living active end is reacted with a coupling agent to obtain a coupled methacrylate-alkyl acrylate-alkyl methacrylate triblock copolymer (corresponding to the "-(A)" portion of general formula (I)). p -(B) q -(C) r ― This forms the (corresponding to the " portion). At this time, polymerization is stopped by reacting with a polymerization inhibitor such as alcohol, if necessary.

[0162] Examples of polymerization initiators include organolithium compounds or organometallic compounds such as organometallic complexes. Examples of the above-mentioned organolithium compounds include alkyllithium compounds such as t-butyllithium, and compounds obtained by reacting alkyllithium with 1,1-diphenylethylene, diphenylmethane, etc. Furthermore, these organolithium compounds may be used in combination with inorganic salts such as lithium chloride, lithium salts of alkoxides such as lithium 2-(2-methoxyethoxy)ethoxide, and organoaluminum compounds such as diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum. Examples of the organometallic complexes mentioned above include rare earth metal complexes having a pentamethylcyclopentadienyl group as a ligand, such as bis(pentamethylcyclopentadienyl)samarium methyltetrahydrofuranate and bis(pentamethylcyclopentadienyl)yttrium methyltetrahydrofuranate. Furthermore, these organometallic complexes may be used in combination with alkylaluminum compounds such as trimethylaluminum.

[0163] As the polymerization solvent mentioned above, hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as chloroform, methylene chloride, and carbon tetrachloride; and ether solvents such as tetrahydrofuran and diethyl ether can be used. A preferred example of the triblock copolymer according to this embodiment is a polymer containing 90 to 99% by mass of n-butyl acrylate monomer units.

[0164] <Other adhesive resins> The adhesive layer of the adhesive tape of this embodiment preferably contains a triblock copolymer having repeating units represented by the general formula (I) above as the adhesive resin. If necessary, it may further contain other adhesive resins besides the triblock copolymer, such as a diblock copolymer, an acrylic adhesive resin, a rubber adhesive resin, or other adhesive resins. Alternatively, it may contain a diblock copolymer, an acrylic adhesive resin, a rubber adhesive resin, or other adhesive resins instead of the triblock copolymer. In this embodiment, the adhesive layer of the adhesive tape preferably consists of 50 to 100% by mass of the triblock copolymer, and more preferably consists of 70 to 100% by mass of the triblock copolymer, relative to the total adhesive resin. When the content of the triblock copolymer in the adhesive resin used in the adhesive layer is within the above range, it is easier to achieve both adhesion, decomposability, and high load-holding capacity.

[0165] --Diblock copolymer-- The adhesive layer of the adhesive tape in this embodiment is given by the following general formula (V): [ka] The material may also contain a diblock copolymer having a repeating unit represented by the above general formula (V), where D and E each independently represent a repeating unit, D represents an alkyl methacrylate monomer unit, E represents an alkyl acrylate monomer unit, and s and t each independently represent the degree of polymerization of each monomer unit. In the above general formula (V), * represents a bond with another atom. In this embodiment, the adhesive layer of the adhesive tape preferably consists of the above-mentioned diblock copolymer at a ratio of 0 to 40% by mass, and more preferably at a ratio of 0 to 20% by mass, relative to the total adhesive resin. When the content of the above-mentioned diblock copolymer in the adhesive resin used in the adhesive layer is within the above range, it is easier to achieve both adhesion, decomposability, and high load-holding capacity. Furthermore, in this embodiment, using a combination of a triblock copolymer and a diblock copolymer as the adhesive resin makes it easier to ensure high elastic modulus and initial adhesion, thereby making it easier to ensure high load-holding capacity, re-peelability over time, and initial adhesion. In particular, when the adhesive tape is pulled, the filler such as acrylic-modified silicone in the adhesive layer can be kept exposed on the surface for a long period of time, resulting in an excellent synergistic effect in combination with the effect of the filler. The alkyl methacrylate monomer unit and alkyl acrylate monomer unit in the above general formula (V) can be in the same form as the alkyl methacrylate monomer unit and alkyl acrylate monomer unit in the above general formula (I). The diblock copolymer has the following general formula (VI): [ka] (In the above general formula (VI), R 8 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituents R 9 The substituent R may be substituted, and 9 R represents a halogen atom, an amino group, or a cyano group. 10 represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are substituents R 11may be replaced, and the substituent R 11 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. It is preferable to have a repeating unit represented by.).

[0166] In the above general formula (VI), R 8 is the same as R 3 in the above general formula (II), and the same embodiment can be applied. In the above general formula (VI), R 10 is the same as R 5 in the above general formula (III), and the same form can be applied. In the above general formula (VI), s and t can have the same form as p and q in the above general formula (I).

[0167] Also, in the present embodiment, it is preferable that the weight average molecular weight Mw of the diblock copolymer is 50,000 to 300,000, and the number average molecular weight Mn is 50,000 to 300,000. For the measurement of the weight average molecular weight, the measurement method of the weight average molecular weight of the triblock copolymer in the present invention can be used.

[0168] In the above general formula (VI), s and t each independently represent the degree of polymerization of each monomer unit. The respective values of s and t are related to the molecular weight and the like. s / (s + t) is preferably 0.01 to 0.99, more preferably 0.1 to 0.9. t / (s + t) is preferably 0.01 to 0.99, more preferably 0.1 to 0.9.

[0169] In the present embodiment, when the diblock copolymer and the triblock copolymer are used in combination, the content of the diblock copolymer is not particularly limited and can be appropriately selected according to the purpose. In the present embodiment, it is preferable to contain 0 to 100 parts by mass, more preferably 1 to 50 parts by mass, and even more preferably 10 to 50 parts by mass of the diblock copolymer with respect to 100 parts by mass of the triblock copolymer. When the content range of the tackifier resin in the adhesive layer is within the above range, it becomes easier to ensure the adhesion to the adherend.

[0170] As an acrylic adhesive resin, it is preferable to use one that contains a tackifying resin in order to improve adhesion to the adherend and surface bonding strength. There are no particular restrictions on the tackifying resin contained in the acrylic adhesive resin, and it can be appropriately selected according to the purpose, but it is preferable that the softening point is 30°C to 180°C, and more preferably 70°C to 140°C for forming an adhesive layer with high adhesive performance. When using a (meth)acrylate-based tackifying resin, it is preferable that its glass transition temperature is 30°C to 200°C, and more preferably 50°C to 160°C.

[0171] Specific examples of tackifying resins contained in acrylic adhesive resins include rosin-based tackifying resins, polymerized rosin-based tackifying resins, polymerized rosin ester-based tackifying resins, rosin-phenol-based tackifying resins, stabilized rosin ester-based tackifying resins, disproportionated rosin ester-based tackifying resins, hydrogenated rosin ester-based tackifying resins, terpene-based tackifying resins, terpene-phenol-based tackifying resins, petroleum resin-based tackifying resins, and (meth)acrylate-based tackifying resins. These may be used individually or in combination of two or more. Among these, polymerized rosin ester-based tackifying resins, rosin-phenol-based tackifying resins, disproportionated rosin ester-based tackifying resins, hydrogenated rosin ester-based tackifying resins, terpene-phenol-based resins, and (meth)acrylate-based resins are preferred as tackifying resins.

[0172] There are no particular restrictions on the amount of tackifying resin used, and it can be appropriately selected depending on the purpose. However, it is preferable to use an amount in the range of 5 to 65 parts by mass per 100 parts by mass of acrylic polymer, and more preferably in the range of 8 to 55 parts by mass, as this makes it easier to ensure adhesion to the adherend. Furthermore, for at least the third adhesive layer, preferably the adhesive layers on both sides adjacent to the foam layer (the third adhesive layer in the first embodiment, and the second, third, and fourth adhesive layers in the second, third, and fourth embodiments described later), it is even more preferable to use tackifying resin in an amount of 5 to 40 parts by mass per 100 parts by mass of acrylic polymer.

[0173] As for the acrylic adhesive resin, it is preferable to use one that contains a crosslinking agent in order to further improve the cohesive strength of the adhesive layer.

[0174] There are no particular restrictions on the crosslinking agent, and it 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 individually or in combination of two or more. Among these, a crosslinking agent that is mixed after the production of the acrylic polymer to allow the crosslinking reaction to proceed is preferred, and isocyanate-based and epoxy-based crosslinking agents, which have high reactivity with acrylic polymers, are more preferable.

[0175] Examples of isocyanate-based crosslinking agents include tolylene diisocyanate, triphenylmethane isocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and trimethylolpropane-modified tolylene diisocyanate. These may be used individually or in combination of two or more. Among these, trifunctional polyisocyanate compounds such as tolylene diisocyanate and its trimethylolpropane adducts, and triphenylmethane isocyanate are particularly preferred.

[0176] As an indicator of the degree of crosslinking, the gel fraction value, which is the amount of insoluble material measured after immersing the adhesive layer in toluene for 24 hours, is used. There are no particular restrictions on the gel fraction of the adhesive layer in this embodiment, and it can be appropriately selected according to the purpose, but 10% to 70% by mass is preferred, 25% to 65% by mass is more preferred, and 35% to 60% by mass is even more preferred for obtaining an adhesive layer with good cohesiveness and adhesion.

[0177] The gel fraction refers to the value measured by the following method. An adhesive composition containing adhesive resin and, if necessary, additives is applied to a release sheet so that the thickness after drying is 50 μm. The sheet is dried at 100°C for 3 minutes and aged at 40°C for 2 days. The resulting sample is cut into 50 mm squares. Next, the mass of the sample before immersion in toluene (G1) is measured. After immersion in toluene solution at 23°C for 24 hours, the toluene-insoluble portion of the sample is separated by filtration through a 300-mesh wire mesh. The mass of the residue after drying at 110°C for 1 hour (G2) is measured, and the gel fraction is determined according to the following formula (4). The mass of conductive fine particles in the sample (G3) is calculated from the mass of the sample (G1) and the composition of the adhesive composition. Gel fraction (mass%) = (G2-G3) / (G1-G3) × 100 ... Formula (4)

[0178] --Rubber-based adhesive resin-- The rubber-based adhesive resin that can be used in the adhesive layer of this embodiment is not particularly limited, and generally, rubber materials that can be used as adhesive resins (for example, synthetic rubber-based adhesive resins or natural rubber-based adhesive resins, etc.) are included. The rubber material may also contain additives such as tackifying resins as needed.

[0179] Specific examples of the above-mentioned rubber material include block copolymers of aromatic vinyl compounds and conjugated diene compounds. Preferred block copolymers include styrene-isoprene copolymers, styrene-isoprene-styrene copolymers, styrene-isoprene-butadiene-styrene copolymers, styrene-butadiene-styrene copolymers, styrene-ethylene-butylene copolymers, styrene-ethylene-propylene copolymers, and hydrogenated versions thereof, as well as other styrene-based resins. The rubber material may be used alone or in combination of two or more types. Among these, the use of two or more styrene-based resins in combination is more preferable because it imparts excellent adhesive properties and holding power to the adhesive tape. In particular, it is preferable to use a mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer.

[0180] The styrene-based resin described above may be a single resin having a linear, branched, or multi-branched structure, or it may be a mixture of resins having different structures. When a styrene-based resin rich in the linear structure is used in the adhesive layer, the adhesive tape has excellent adhesive performance. On the other hand, a resin having a branched or multi-branched structure and with styrene blocks at the molecular ends can form a pseudo-crosslinked structure, and therefore exhibits excellent cohesive force, thus providing high holding power to the adhesive layer. For this reason, it is preferable to mix the styrene-based resins used as adhesive resins according to the required properties. The styrene-based resin described above preferably contains structural units represented by the following general formula (3) in an amount of 10% to 80% by mass, more preferably 12% to 60% by mass, even more preferably 15% to 40% by mass, and particularly preferably 17% to 35% by mass, relative to the total mass of the styrene-based resin. This allows for excellent adhesion and heat resistance. [ka]

[0181] When using a combination of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer as the styrene resin used in the adhesive resin of the present embodiment, the content of the styrene-isoprene copolymer with respect to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is preferably 0% to 80% by mass, more preferably 0% to 77% by mass, still more preferably 0% to 75% by mass, and particularly preferably 0% to 70% by mass. When the content of the styrene-isoprene copolymer is within the above preferred range, an adhesive tape having both excellent adhesion performance and heat durability can be provided.

[0182] The weight average molecular weight (Mw) of the above styrene-isoprene copolymer is preferably in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and still more preferably in the range of 50,000 to 300,000. The weight average molecular weight is a value measured using gel permeation chromatography (GPC) in terms of standard polystyrene. When the weight average molecular weight of the styrene-isoprene copolymer is within the above range, heat fluidity or compatibility during solvent dilution can be ensured, so that a good workability can be ensured in the manufacturing process and an adhesive tape with heat durability can be obtained, which is preferable.

[0183] The measurement of the weight average molecular weight (Mw) of the styrene-isoprene copolymer by the above GPC is a value in terms of standard polystyrene measured using a GPC device (SC-8020, manufactured by Tosoh Corporation), and the measurement conditions are as follows. -Measurement conditions- · Sample concentration: 0.5% by mass (THF (tetrahydrofuran) solution) · Sample injection volume: 100 μL · Eluent: THF · Flow rate: 1.0 mL / min · Measurement temperature: 40 °C · This column: 2 pieces of TSKgel (registered trademark) GMHHR-H(20) · Guard column: TSKgel HXL-H • Detector: Differential refractometer • Standard polystyrene molecular weight: 10,000 to 20,000,000 (manufactured by Tosoh Corporation)

[0184] The method for producing the styrene-based resin used in the adhesive resin of this embodiment is not particularly limited and can be appropriately selected from known production methods. For example, the target styrene-based resin can be produced by preparing a block copolymer by anionic living polymerization and then adding a coupling agent as needed and reacting it. Furthermore, the method for producing the styrene-isoprene copolymer, which is a preferred example of the styrene-based resin, is not particularly limited and can be appropriately selected from known production methods. For example, a method of sequentially polymerizing a styrene block and an isoprene block by anionic living polymerization can be used.

[0185] Furthermore, the method for producing the styrene-isoprene-styrene copolymer, which is a preferred example of the styrene-based resin, is not particularly limited and can be appropriately selected from known production methods. For example, this could involve sequentially polymerizing a styrene block and an isoprene block by an anionic living polymerization method, or producing a block copolymer by first producing a block copolymer having living active ends and then reacting it with a coupling agent.

[0186] The method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from known production methods. For example, one method is to mix the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer produced by the above method using known mixing means.

[0187] Furthermore, another method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer may be to produce the mixture simultaneously in a single polymerization step. A more specific method for producing the above-mentioned styrene-isoprene copolymer and mixture of styrene-isoprene-styrene copolymer may include the following first to fourth steps using anionic living polymerization. The first step involves polymerizing styrene monomers in a polymerization solvent using an anionic polymerization initiator to form polystyrene blocks having living active ends. The second step involves polymerizing isoprene from the living active ends of a polystyrene block to obtain a styrene-isoprene block copolymer having living active ends. The third step involves reacting a portion of the styrene-isoprene block copolymer having living active ends with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. The fourth step is to deactivate the living active ends of the remaining styrene-isoprene block copolymer, which has living active ends, using a polymerization inhibitor, thereby forming a styrene-isoprene block copolymer.

[0188] The tackifying resin used in combination with the rubber-based adhesive resin is not particularly limited and can be appropriately selected depending on the purpose. For example, it is preferable to use a tackifying resin with a softening point of 80°C or higher. This makes it possible to provide an adhesive tape that combines excellent initial adhesion with heat durability.

[0189] As the tackifying resin used in combination with the rubber-based adhesive resin, a resin that is solid at room temperature (23°C) is preferred. Specific examples of such tackifying resins include petroleum resins, polymerized rosin resins, terpene resins, rosin resins, terpene-phenol resins, styrene resins, coumarone-indene resins, xylene resins, or phenol resins. Examples of such petroleum resins include C5-type petroleum resins, C9-type petroleum resins, C5-type / C9-type petroleum resins, and alicyclic petroleum resins. These resins may be used individually or in combination of two or more. Among these, when used in combination with the rubber-based adhesive resin, a combination of C5-type petroleum resin and polymerized rosin resin is preferred from the viewpoint of achieving both even better initial adhesion and heat durability. The above-mentioned petroleum resin is easily compatible with the styrene monomer units represented by the general formula (3) that constitute the styrene-based resin. Therefore, the initial adhesive strength and heat durability of the adhesive tape can be further improved.

[0190] Examples of the above-mentioned C5-type petroleum resins include the Escorets series from ExxonMobil (Escorets 1202, Escorets 1304, or Escorets 1401), Wingtack 95 from Goodyear Tire & Rubber Company, the Quinton series from Nippon Zeon Corporation (Quinton K100, Quinton R100, or Quinton F100), or Picotack 95 or Picopail 100 from Rika Hercules Corporation.

[0191] Examples of the above-mentioned C9-type petroleum resins include the Nisseki Neopolymer series manufactured by JX Nippon Oil & Energy Corporation (Nisseki Neopolymer L-90, Nisseki Neopolymer 120, Nisseki Neopolymer 130, Nisseki Neopolymer 140, Nisseki Neopolymer 150, Nisseki Neopolymer 170S, Nisseki Neopolymer 160, Nisseki Neopolymer E-100, Nisseki Neopolymer E-130, Nisseki Neopolymer 130S, or Nisseki Neopolymer S), and Petocol (registered trademark) manufactured by Tosoh Corporation.

[0192] The above-mentioned C5 / C9 petroleum resin can be a copolymer of C5 petroleum resin and C9 petroleum resin. Specific examples of C5 / C9 petroleum resins include, for example, Escorets 2101 manufactured by ExxonMobil, Quinton G115 manufactured by Zeon Corporation, or Harcotac 1149 manufactured by Rika Hercules Corporation.

[0193] The above-mentioned alicyclic petroleum resins can be obtained by hydrogenating C9 petroleum resins. Examples include Escorets 5300 manufactured by ExxonMobil, Alcon P-100 manufactured by Arakawa Chemical Industries, Ltd., and Rigalite R101 manufactured by Rika Hercules, Inc.

[0194] The amount of tackifying resin used in combination with the rubber-based adhesive resin is not particularly limited and can be appropriately selected according to the purpose. It is preferable to use the tackifying resin in the range of 0% to 100% by mass, more preferably in the range of 0% to 70% by mass, even more preferably in the range of 0% to 50% by mass, and particularly preferably in the range of 0% to 30% by mass, relative to the total amount (100% by mass) of the components constituting the rubber-based adhesive resin. Using the tackifying resin within this preferred range improves adhesion at the interface between the adhesive layer and the substrate layer, and makes it easier to achieve both excellent break elongation and thermal durability of the adhesive tape.

[0195] There are no particular restrictions on the amount of tackifying resin having a softening point of 80°C or higher used, and it can be appropriately selected according to the purpose. For example, it is preferable to use 3% to 100% by mass of tackifying resin having a softening point of 80°C or higher relative to the total amount of styrene resin, more preferably in the range of 5% to 80% by mass, and particularly preferable to use in the range of 5% to 80% by mass when there is an emphasis on providing an adhesive tape that achieves both even better adhesion and excellent heat resistance.

[0196] Furthermore, in order to obtain adhesiveness or initial adhesion in a constant temperature environment, a tackifying resin having a softening point of 80°C or higher may be used in combination with a tackifying resin having a softening point of -5°C or lower. The tackifying resin having a softening point of -5°C or lower is not particularly limited and can be appropriately selected from known tackifying resins depending on the purpose. For example, it is preferable to use a liquid tackifying resin at room temperature (20°C to 27°C).

[0197] Specific examples of tackifying resins having a softening point of -5°C or lower include process oils, polyesters, or liquid rubbers such as polybutene. These liquid rubbers may be used individually or in combination of two or more. From the viewpoint of exhibiting even better initial adhesion, it is preferable to use polybutene as the tackifying resin having a softening point of -5°C or lower.

[0198] The tackifying resin having a softening point of -5°C or lower preferably accounts for 0% to 40% by mass, and more preferably 0% to 30% by mass, relative to the total amount of the tackifying resin (100% by mass).

[0199] Furthermore, the tackifying resin having a softening point of -5°C or lower is preferably used in an amount of 0% to 40% by mass relative to the total amount (100% by mass) of the styrene-based resin used as the adhesive resin. If the viewpoint of improving initial adhesion, having good adhesion, and exhibiting sufficient heat resistance is important, it is more preferable to use it in an amount of 0% to 30% by mass.

[0200] There are no particular restrictions on the mass ratio of the tackifying resin having a softening point of 80°C or higher to the tackifying resin having a softening point of -5°C or lower, and it can be appropriately selected according to the purpose. It is preferable to use a mass ratio of the tackifying resin having a softening point of 80°C or higher to the tackifying resin having a softening point of -5°C or lower, expressed as [mass of tackifying resin having a softening point of 80°C or higher / mass of tackifying resin having a softening point of -5°C or lower], in the range of 5 to 50. If the viewpoint of obtaining an adhesive tape that achieves both excellent initial adhesion and excellent holding power is important, it is more preferable to use a range of 10 to 30.

[0201] There are no particular restrictions on the mass ratio of the styrene resin to the tackifying resin used in combination with the rubber adhesive resin, and it can be appropriately selected according to the purpose. For example, it is preferable to use a mass ratio of styrene resin to tackifying resin represented as [styrene resin / tackifying resin used in combination with rubber adhesive resin] in the range of 0.5 to 10.0, which can improve initial adhesion, and it is more preferable to use a range of 0.6 to 9.0 when the viewpoint of obtaining excellent heat durability is important. Furthermore, it is preferable for the mass ratio [styrene resin / tackifying resin used in combination with rubber adhesive resin] to be greater than 1, for example, in order to prevent peeling due to the repulsive force of the adhesive tape when it is applied to curved surfaces of the adherend (repulsion resistance).

[0202] -Other ingredients- Other components included in the adhesive layer of this embodiment are not particularly limited and can be appropriately selected within a range that does not impair the properties of the adhesive tape. Examples include polymer components other than the adhesive resin, crosslinking agents, antioxidants, UV absorbers, fillers, polymerization inhibitors, surface modifiers, antistatic agents, defoamers, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, plasticizers, softeners, flame retardants, metal deactivators, silica beads, organic beads, and other additives; and inorganic fillers such as silicon dioxide, aluminum oxide, titanium dioxide, zirconia, and antimony pentoxide. These other components may be used individually or in combination of two or more. The content of other components in the adhesive layer can be appropriately selected within a range that does not impair the properties of the adhesive tape.

[0203] -Other adhesive resins- In this embodiment, as the adhesive resin, a mixed adhesive resin other than the above-mentioned adhesive resin may be used, such as an acrylic mixed adhesive, a rubber mixed adhesive, a urethane mixed adhesive, an adhesive composition, an adhesive, or an adhesive resin, as described below. (Acrylic mixed adhesive) The above-mentioned mixed adhesive may be an acrylic mixed adhesive containing an acrylic polymer as a base resin, from the viewpoint of adhesive properties (e.g., shear adhesion), molecular design, and long-term stability. In this specification, "base resin" refers to the main component of the resin component contained in the mixed adhesive (e.g., a component present in more than 50% by mass).

[0204] (Acrylic polymer) The above-mentioned acrylic polymer is preferably a polymer of monomer raw materials that contains, for example, an alkyl (meth)acrylate as the main monomer component, and further contains a secondary monomer component that is copolymerizable with the main monomer component. Here, the main monomer component refers to a component that accounts for more than 50% by mass of the total monomer components in the above-mentioned monomer raw materials.

[0205] In this embodiment, as the alkyl (meth)acrylate, for example, a compound represented by the following general formula (4) can be suitably used. [ka] (R in equation (4) above) 13 R represents a hydrogen atom or a methyl group. 14 This refers to a chain-like alkyl group having 1 to 20 carbon atoms (hereinafter, this range of carbon atoms may be referred to as "C1-20"). From the viewpoint of the storage modulus of the adhesive resin, R in the above general formula (4) 14A C1-14 (e.g., C2-10, more preferably C4-8) linear alkyl (meth)acrylate is preferred, R 13 R is a hydrogen atom 14 Alkyl acrylates in which the C4-8 chain alkyl group is more preferred. 14 Alkyl (meth)acrylates, in which the C1-20 chain alkyl group is, can be used individually or in combination of two or more. Preferred alkyl (meth)acrylates include n-butyl acrylate and 2-ethylhexyl acrylate. From the viewpoint of adhesive properties and prevention of adhesive residue, n-butyl acrylate is more preferred.

[0206] The proportion of the main monomer component in the total monomer components is preferably 70% by mass or more (for example, 85% by mass or more, more preferably 90% by mass or more). There is no particular upper limit to the proportion of the main monomer component, but it is preferably 99.5% by mass or less (for example, 99% by mass or less).

[0207] A monomer copolymerizable with the main monomer, alkyl(meth)acrylate, is useful for introducing crosslinking points into acrylic polymers or for enhancing the cohesive force of acrylic polymers. As the monomer of the minor component, one or more functional group-containing monomers such as carboxyl group-containing monomers, hydroxyl group-containing monomers, acid anhydride group-containing monomers, amide group-containing monomers, amino group-containing monomers, keto group-containing monomers, monomers having nitrogen atom-containing rings, alkoxysilyl group-containing monomers, imide group-containing monomers, and epoxy group-containing monomers can be used. For example, from the viewpoint of improving cohesive force, an acrylic polymer copolymerized with a carboxyl group-containing monomer and / or a hydroxyl group-containing monomer as the monomer of the minor component is preferred. Suitable examples of the carboxyl group-containing monomer include acrylic acid and methacrylic acid. Examples of the hydroxyl group-containing monomers mentioned above include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, as well as unsaturated alcohols. Among these, hydroxyalkyl (meth)acrylates are preferred, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are more preferred.

[0208] The amount of monomers of the above-mentioned auxiliary components can be appropriately selected to achieve the desired cohesive force and is not particularly limited. Generally, from the viewpoint of achieving a good balance between adhesive strength and cohesive strength, the amount of monomers of the auxiliary components is appropriate to be 0.5% by mass or more of the total monomer components forming the acrylic polymer, preferably 1% by mass or more. Furthermore, the amount of monomers of the auxiliary components is appropriate to be 30% by mass or less of the total monomer components, preferably 10% by mass or less (for example, 5% by mass or less). When hydroxyl group-containing monomers are copolymerized into the acrylic polymer, the content of hydroxyl group-containing monomers is preferably in the range of about 0.001 to 10% by mass (for example, 0.01 to 5% by mass, preferably 0.05 to 2% by mass) of the total monomer components used in the synthesis of the acrylic polymer. This makes it possible to achieve an adhesive resin with a higher level of balance between adhesive strength and cohesive strength.

[0209] The acrylic polymers of this disclosure may be copolymerized with monomers other than those mentioned above (other monomers) to the extent that they do not significantly impair the effects of the present invention. These other monomers can be used, for example, to adjust the glass transition temperature of the acrylic polymer, adjust the adhesive properties (e.g., peelability), etc. Examples of monomers that can improve the cohesive strength of adhesive resins include sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, vinyl esters, aromatic vinyl compounds, etc. These other monomers may be used individually or in combination of two or more. Among these, vinyl esters are particularly preferred. Specifically, vinyl esters include vinyl acetate, vinyl propionate, vinyl laurate, etc. Among these, vinyl acetate is preferred. The content of these other monomers is preferably about 30% by mass or less (for example, 0.01 to 30% by mass, more preferably 0.1 to 10% by mass) of the total monomer components used in the synthesis of the acrylic polymer.

[0210] The copolymerization composition of the above-mentioned acrylic polymer is preferably designed so that the glass transition temperature (Tg) of the polymer is -15°C or lower (for example, -70°C or higher and -15°C or lower), more preferably -25°C or lower (for example, -60°C or higher and -25°C or lower), and even more preferably -40°C or lower (for example, -60°C or higher and -40°C or lower). Setting the Tg of the acrylic polymer to be below the above-mentioned upper limit is preferable from the viewpoint of impact resistance of the adhesive tape, etc.

[0211] The Tg of an acrylic polymer can be adjusted by appropriately changing the monomer composition (i.e., the type and ratio of monomers used in the synthesis of the polymer). Here, the Tg of an acrylic polymer refers to the value calculated from Fox's formula shown below, based on the Tg of the homopolymer of each monomer constituting the polymer and the mass fraction (mass-based copolymerization ratio) of the monomers. Fox's formula is a relationship between the Tg of a copolymer and the glass transition temperature Tgj of the homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below. 1 / Tg = Σ(Mj / Tgj) (In the above Fox formula, Tg represents the glass transition temperature (K) of the copolymer, Mj represents the mass fraction (mass-based copolymerization ratio) of monomer j in the copolymer, and Tgj represents the glass transition temperature (K) of the homopolymer of monomer j.) The Tg of the homopolymer shall be the value specified in conventionally known literature or materials.

[0212] In this embodiment, the following values ​​are specifically used as the Tg of the above-mentioned homopolymer. 2-Ethylhexyl acrylate 203.15K Butyl acrylate 218.15K Vinyl acetate 305.15K Acrylic acid 379.15K Methacrylic acid 501.15K 2-Hydroxyethyl acrylate 258.15K For homopolymers other than those specified above, the Tg values ​​shall be those listed in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). If the Tg value for a homopolymer is not listed in the Polymer Handbook, the value obtained by the measurement method described in, for example, Japanese Patent Publication No. 2007-51271 shall be used.

[0213] The method for producing acrylic polymers is not particularly limited. Any commonly known polymerization method for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization, can be appropriately employed. For example, acrylic polymers are preferably produced by solution polymerization. When performing solution polymerization, the monomer supply method can be appropriately adopted, such as a batch supply method where all monomer raw materials are supplied at once, a continuous supply (dropping) method, or a divided supply (dropping) method. Furthermore, the polymerization temperature can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc. For example, the polymerization temperature can be set to approximately 20°C to 170°C (e.g., 40°C to 140°C). Alternatively, photopolymerization (for example, carried out in the presence of a photopolymerization initiator) or active energy ray irradiation polymerization (carried out by irradiation with active energy rays such as beta rays or gamma rays) may be used.

[0214] The solvent used for solution polymerization (polymerization solvent) can be appropriately selected from known organic solvents. For example, aromatic compounds such as toluene (e.g., aromatic hydrocarbons), aliphatic or alicyclic hydrocarbons such as ethyl acetate are preferably used.

[0215] The polymerization initiator used for polymerization can be appropriately selected from known polymerization initiators depending on the type of polymerization method. For example, one or more azo polymerization initiators such as 2,2'-azobisisobutyronitrile can be preferably used. Other examples of polymerization initiators include peroxide initiators such as benzoyl peroxide and hydrogen peroxide; persulfates such as potassium persulfate; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds. Yet another example of polymerization initiators is a redox polymerization initiator, which is a combination of a peroxide and a reducing agent. The above polymerization initiators may be used individually or in combination of two or more. The amount of polymerization initiator used can be the usual amount, for example, it can be selected from a range of about 0.005 to 1 part by mass (e.g., 0.01 to 1 part by mass) per 100 parts by mass of the total monomer components.

[0216] The weight-average molecular weight (Mw) of the base resin (preferably an acrylic polymer) in this disclosure is not particularly limited, but for example, 10 × 10 4 500 x 10 4 The following ranges are possible. From the viewpoint of balancing cohesive force and adhesive force at a high level, the Mw of the base resin (preferably an acrylic polymer) is preferably 10 × 10 4 ~150×10 4 , fer20×10 4 ~110×10 4 (For example, 20 x 10 4 ~75×10 4 ), more preferably 35 × 10 4 ~90×10 4 (For example, 35 x 10 4 ~65×10 4 ) is within the range. Here, the measured value of Mw refers to the value obtained by gel permeation chromatography (GPC) on a standard polystyrene basis. As the GPC apparatus, for example, "HLC-8320GPC" (column: TSKgelGMH-H(S), manufactured by Tosoh Corporation) can be used. The same applies to the examples described later.

[0217] (Rubber-based mixed adhesive) In this embodiment, the adhesive resin may be composed of a rubber-based mixed adhesive. A preferred embodiment of the rubber-based mixed adhesive contains a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as the base resin. The monovinyl-substituted aromatic compound refers to a compound in which a functional group having one vinyl group is bonded to an aromatic ring. An example of the aromatic ring is a benzene ring (which may be a benzene ring substituted with a functional group that does not have a vinyl group (e.g., an alkyl group)). Specific examples of the monovinyl-substituted aromatic compound include styrene, α-methylstyrene, vinyltoluene, or vinylxylene. Specific examples of the conjugated diene compound include 1,3-butadiene or isoprene. Such block copolymers can be used individually or in combination of two or more as the base resin.

[0218] In the above block copolymer, the X block (also referred to as a rigid segment or rigid block) has a copolymerization ratio of the monovinyl-substituted aromatic compound (two or more may be used in combination) of preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass. In the above block copolymer, the Y block (also referred to as a flexible segment or flexible block) has a copolymerization ratio of the conjugated diene compound (two or more may be used in combination) of preferably 70% by mass or more, more preferably 90% by mass or more, and substantially 100% by mass. Such a block copolymer can realize an adhesive tape with higher performance.

[0219] The block copolymer described above is preferably a diblock polymer, a triblock polymer, a radial polymer, or a mixture thereof. In triblock polymers and radial polymers, it is preferable that X blocks (e.g., styrene blocks) are arranged at the ends of the polymer chains. This is because X blocks arranged at the ends of polymer chains readily aggregate to form domains, thereby forming a pseudo-crosslinked structure and improving the cohesiveness of the adhesive resin. As for the block copolymer of this disclosure, from the viewpoint of adhesive strength (peel strength) and repulsion resistance to the adherend, for example, the diblock polymer ratio is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and particularly preferably 70% by mass or more. Furthermore, from the viewpoint of resistance to continuously applied stress, a block copolymer with a diblock polymer ratio of 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less can be used. For example, the use of a block copolymer with a diblock polymer ratio of 60 to 85% by mass is preferred.

[0220] (Styrene-based block copolymer) In a preferred embodiment of the adhesive resin of this disclosure, a mixed adhesive in which the base resin is a styrene-based block copolymer is preferred. As the styrene-based block copolymer, for example, it is preferable that the base resin contains at least one of a styrene-isoprene block copolymer and a styrene-butadiene block copolymer. Of the styrene-based block copolymer contained in the adhesive resin, it is preferable that the proportion of styrene-isoprene block copolymer accounts for 70% by mass or more, that the proportion of styrene-butadiene block copolymer accounts for 70% by mass or more, or that the total proportion of styrene-isoprene block copolymer and styrene-butadiene block copolymer accounts for 70% by mass or more. It is preferable that substantially the entirety (for example, 95 to 100% by mass) of the styrene-based block copolymer is a styrene-isoprene block copolymer. It is preferable that substantially the entirety (for example, 95 to 100% by mass) of the styrene-based block copolymer is a styrene-butadiene block copolymer. With this composition, an adhesive tape with excellent rebound resistance and a good balance with other adhesive properties can be suitably realized.

[0221] The above-mentioned styrene-based block copolymer is preferably in the form of a diblock polymer, a triblock polymer, a radial polymer, or a mixture thereof. In triblock polymers and radial polymers, it is preferable that styrene blocks are arranged at the ends of the polymer chains. This is because styrene blocks arranged at the ends of polymer chains readily aggregate to form styrene domains, thereby forming a pseudo-crosslinked structure and improving the cohesiveness of the adhesive resin. In styrene-based block copolymers, the upper and lower limits of the diblock polymer ratio can be derived from the values ​​for the above-mentioned block copolymers.

[0222] The styrene content of the above-mentioned styrene-based block copolymer is preferably 5 to 40% by mass relative to the total amount of the styrene-based block copolymer. From the viewpoint of repulsion resistance and retention force, the styrene content of the styrene-based block copolymer is preferably 10% by mass or more, more preferably more than 10% by mass, and even more preferably 12% by mass or more. Furthermore, from the viewpoint of adhesive strength to the adherend, a styrene-based block copolymer with a styrene content of 35% by mass or less (for example, 30% by mass or less, more preferably 25% by mass or less, for example, less than 20% by mass) is preferred. For example, a styrene-based block copolymer with a styrene content of 12% by mass or more and less than 20% by mass is particularly preferred.

[0223] (Urethane-based mixed adhesive) The adhesive resin can be composed of a urethane-based mixed adhesive. Here, a urethane-based mixed adhesive refers to an adhesive that contains a urethane polymer as a base resin. The above urethane-based mixed adhesive consists of a urethane resin that contains a urethane polymer obtained by reacting a polyol with a polyisocyanate compound as a base resin. There are no particular limitations on the urethane polymer, but an appropriate one can be selected from various urethane polymers that can function as an adhesive resin (ether-based polyurethane, ester-based polyurethane, carbonate-based polyurethane, etc.). Examples of polyols include polyether polyol, polyester polyol, polycarbonate polyol, and polycaprolactone polyol. Examples of polyisocyanate compounds include diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate.

[0224] (Adhesive composition) The adhesive resin in this embodiment may be an adhesive formed from an aqueous adhesive composition, a solvent-type adhesive composition, a hot-melt adhesive composition, or an active energy ray-curable adhesive composition. An aqueous adhesive composition refers to an adhesive composition in which an adhesive (adhesive layer-forming component) is contained in a solvent (aqueous solvent) mainly composed of water, and includes compositions such as a water-dispersible adhesive composition (a composition in which at least a portion of the adhesive is dispersed in water). A solvent-type adhesive composition refers to an adhesive composition in which an adhesive is contained in an organic solvent. This disclosure is preferably implemented in an embodiment comprising an adhesive formed from a solvent-type adhesive composition, with an emphasis on suitably realizing adhesive properties such as shear adhesion.

[0225] (Acrylic oligomers) The adhesive composition of this disclosure may contain an acrylic oligomer. By using an acrylic oligomer, impact resistance and rebound resistance can be improved in a balanced manner. Furthermore, when the adhesive composition is cured by active energy ray irradiation (e.g., UV irradiation), acrylic oligomers have the advantage of being less likely to cause curing inhibition (e.g., inhibition of polymerization of unreacted monomers) compared with tackifying resins such as rosin resins and terpene resins. Note that an acrylic oligomer is defined as a polymer that contains an acrylic monomer as a constituent monomer component, and has a smaller Mw than the above-mentioned acrylic polymer.

[0226] The proportion of acrylic monomers in the total monomer components constituting the acrylic oligomer is, for example, more than 50% by mass, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. In one preferred embodiment, the acrylic oligomer has a monomer composition consisting substantially only of acrylic monomers.

[0227] As constituent monomer components of the acrylic oligomer, chain-like alkyl (meth)acrylates, functional group-containing monomers, and other monomers exemplified as monomers that can be used in the above-mentioned acrylic polymer can be used. Furthermore, the above-mentioned constituent monomers may also contain alicyclic hydrocarbon group-containing (meth)acrylates. As constituent monomer components of the acrylic oligomer, one or more of the various monomers exemplified above can be used.

[0228] The above chain-like alkyl (meth)acrylate is R in formula (II) above. 3 Alkyl (meth)acrylates having 1 to 12 carbon atoms (for example, more preferably C1-8) are preferably used. Preferred examples include methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl methacrylate, t-butyl acrylate, and 2-ethylhexyl acrylate. Among these, methyl methacrylate is more preferred.

[0229] Preferred examples of the above-mentioned functional group-containing monomers include monomers having a nitrogen atom-containing ring (e.g., a nitrogen atom-containing heterocycle) such as N-vinyl-2-pyrrolidone and N-acryloylmorpholine; amino group-containing monomers such as N,N-dimethylaminoethyl (meth)acrylate; amide group-containing monomers such as N,N-diethyl (meth)acrylamide; carboxyl group-containing monomers such as acrylic acid and methyl methacrylate; and hydroxyl group-containing monomers such as ethylhexyl acrylate.

[0230] The above-mentioned alicyclic hydrocarbon group-containing (meth)acrylate may be one or more (meth)acrylates containing an alicyclic hydrocarbon group having 4 to 20 carbon atoms. The number of carbon atoms constituting the above-mentioned alicyclic hydrocarbon group is preferably 5 or more (for example, 6 or more, more preferably 8 or more), and also preferably 16 or less (for example, 12 or less, more preferably 10 or less). Examples of the above-mentioned alicyclic hydrocarbon group-containing (meth)acrylate include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, or dicyclopentanyl (meth)acrylate. Among these, dicyclopentanyl methacrylate is more preferred.

[0231] The proportion of the alicyclic hydrocarbon group-containing (meth)acrylate in the total monomer components constituting the above acrylic oligomer (i.e., the copolymerization ratio) is preferably about 30 to 90% by mass (for example, 50 to 80% by mass, more preferably 55 to 70% by mass) from the viewpoint of adhesion or cohesiveness.

[0232] A preferred form of the acrylic oligomer includes a linear alkyl (meth)acrylate and / or an alicyclic hydrocarbon group-containing (meth)acrylate as monomer components constituting the acrylic oligomer. In this embodiment, the proportion of the linear alkyl group-containing and alicyclic hydrocarbon group-containing (meth)acrylic acid esters in the total monomer components constituting the acrylic oligomer is preferably about 80% by mass or more (for example, 90-100% by mass, more preferably 95-100% by mass). It is more preferable that the monomer components constituting the acrylic oligomer consist substantially of linear alkyl (meth)acrylate and / or an alicyclic hydrocarbon group-containing (meth)acrylate.

[0233] When an acrylic oligomer is a copolymer of monomer mixtures containing a linear alkyl (meth)acrylate and an alicyclic hydrocarbon group-containing (meth)acrylate, the composition ratio of the linear alkyl (meth)acrylate to the alicyclic hydrocarbon group-containing (meth)acrylate is not particularly limited. In one preferred embodiment, the mass ratio (M) of the linear alkyl (meth)acrylate in the constituent monomer components of the acrylic oligomer is Ch ) and the mass ratio of alicyclic hydrocarbon group-containing (meth)acrylate (M Ali ) and the mass ratio (M Ch :M Ali The ratio is 1:9 to 9:1, preferably 2:8 to 7:3 (for example, 3:7 to 6:4, more preferably 3:7 to 5:5).

[0234] The composition of the monomer components constituting the acrylic oligomer (i.e., the polymerization composition) is not particularly limited and can be set so that the Tg of the acrylic oligomer is between 10°C and 300°C. Here, the Tg of the acrylic oligomer refers to a value calculated based on the composition of the monomer components constituting the acrylic oligomer, in the same manner as the Tg based on the monomer composition. From the viewpoint of initial adhesion, the Tg of the acrylic oligomer is preferably 180°C or lower (for example, 160°C or lower). Furthermore, from the viewpoint of the cohesiveness of the adhesive resin, the Tg is preferably 60°C or higher (for example, 100°C or higher, more preferably 120°C or higher).

[0235] The weight-average molecular weight (Mw) of acrylic oligomers is not particularly limited, but for example, 0.1 × 10⁻⁶ 4 ~3×10 4 To that extent, from the viewpoint of improving adhesive properties (e.g., adhesive strength or repulsion resistance), the Mw of the acrylic oligomer is 1.5 × 10 4 The following is preferable: 1 × 10 4 The following is more preferable: 0.8 × 10 4 (For example, 0.6 × 10) 4 The following are even more preferable. Also, from the viewpoint of the cohesiveness of the adhesive resin, the above Mw is 0.2 × 10 4 (For example, 0.3 × 10) 4The above is preferable. The molecular weight of the acrylic oligomer can be adjusted as needed during polymerization using a chain transfer agent.

[0236] Acrylic oligomers can be formed by polymerizing their constituent monomer components. The polymerization method or mode of acrylic oligomers is not particularly limited, and various known polymerization methods (e.g., solution polymerization, emulsion polymerization, bulk polymerization, photopolymerization, or radiation polymerization) can be employed. The types and amounts of polymerization initiators (e.g., azo polymerization initiators such as AIBN) that can be used as needed are generally as described above and will be omitted here.

[0237] The content of the acrylic oligomer in the adhesive composition of this disclosure is preferably, for example, 0.5 parts by mass or more per 100 parts by mass of the acrylic polymer. From the viewpoint of better exhibiting the effects of the acrylic oligomer, the content of the acrylic oligomer is preferably 1 part by mass or more (for example, 1.5 parts by mass or more, more preferably 2 parts by mass or more). Furthermore, from the viewpoint of the curability of the adhesive composition or compatibility with the acrylic polymer, the content of the acrylic oligomer is preferably less than 50 parts by mass (for example, less than 10 parts by mass), and even more preferably less than 8 parts by mass (for example, less than 7 parts by mass, more preferably 5 parts by mass or less). Even with such a small amount of addition, improvements in impact resistance and rebound resistance can be achieved by using the acrylic oligomer.

[0238] (Adhesion agent) The adhesive resin or adhesive composition of this disclosure may also contain a tackifier. The tackifier is not particularly limited. Examples of tackifiers that can be used include rosin-based tackifiers, terpene-based tackifiers, hydrocarbon-based tackifiers, epoxy-based tackifiers, polyamide-based tackifiers, elastomer-based tackifiers, phenol-based tackifiers, or ketone-based tackifiers. The tackifiers may be used individually or in combination of two or more.

[0239] Specific examples of rosin-based tackifying resins include unmodified rosins such as gum rosin, wood rosin, and tall rosin (raw rosin (mainly composed of a tricyclic diterpenoid isomer with 20 carbon atoms called resin acid)); modified rosins obtained by hydrogenation, disproportionation, polymerization, etc. (hydrogenated rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins; the same applies hereinafter); and various other rosin derivatives. Specific examples of the above rosin derivatives include rosin esters such as compounds obtained by esterifying unmodified rosin with alcohols (i.e., rosin esters) and compounds obtained by esterifying modified rosin with alcohols (i.e., modified rosin esters); unsaturated fatty acid modified rosins obtained by modifying unmodified rosin or modified rosin with unsaturated fatty acids; unsaturated fatty acid modified rosin esters obtained by modifying rosin esters with unsaturated fatty acids; rosin alcohols obtained by reducing the carboxyl groups in unmodified rosin, modified rosin, unsaturated fatty acid modified rosins, or unsaturated fatty acid modified rosin esters; metal salts of rosins (especially rosin esters) such as unmodified rosin, modified rosin, and various rosin derivatives; and rosinphenol resins obtained by adding phenol to rosins (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and then thermal polymerization. When an acrylic polymer is used as the base resin, it is preferable to use a rosin-based tackifier. From the viewpoint of improving adhesive properties such as adhesive strength, it is more preferable to use two or three or more types of rosin-based tackifying resins that differ in type and properties (e.g., softening point) in combination.

[0240] Specific examples of terpene-based tackifying resins include terpene resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers; and modified terpene resins obtained by modifying these terpene resins (phenol modification, aromatic modification, hydrogenation modification, hydrocarbon modification, etc.). Specific examples of the above modified terpene resins include terpene-modified phenol resins, styrene-modified terpene resins, aromatic-modified terpene resins, and hydrogenated terpene resins. When using an acrylic polymer as the base resin, it is preferable to use a terpene-based tackifying resin, such as a terpene-modified phenol resin. In particular, from the viewpoint of improving adhesive properties such as adhesive strength, it is more preferable to use one or more types of the above terpene-based tackifying resins (e.g., terpene-modified phenol resins) that differ in type and properties (e.g., softening point) in combination.

[0241] Specific examples of hydrocarbon-based tackifying resins include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic-aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, or coumarone-indene resins, among other hydrocarbon resins.

[0242] In this disclosure, the tackifying resin is preferably one with a softening point (softening temperature) of about 70°C or higher (preferably about 100°C or higher, more preferably about 110°C or higher). By using an adhesive resin or adhesive composition containing the various tackifying resins having the softening points described above, an adhesive tape with superior adhesive strength can be realized. Among the tackifying resins exemplified above, terpene-based tackifying resins (e.g., terpene-modified phenolic resins), rosin-based tackifying resins (e.g., esterified polymerized rosin), etc., having the above softening point can be preferably used. The upper limit of the softening point of the tackifying resin is not particularly limited and can be, for example, about 200°C or lower (e.g., about 180°C or lower).

[0243] In this embodiment, the amount of tackifier used is not particularly limited and can be adjusted as appropriate according to the desired adhesive performance (adhesion strength, etc.). For example, the amount of tackifier used may be, on a solid content basis, preferably about 10 to 100 parts by mass, more preferably 20 to 80 parts by mass, and even more preferably 30 to 60 parts by mass of tackifier per 100 parts by mass of acrylic polymer.

[0244] When the adhesive resin is composed of a rubber-based mixed adhesive, it is preferable that the rubber-based mixed adhesive contains a high-softening-point resin having a softening point of 120°C or higher as the tackifying resin. Adhesive tapes containing such high-softening-point resins are preferable from the viewpoint of repulsion resistance or holding power. In one preferred embodiment, the high-softening-point resin may include a tackifying resin having a softening point of preferably 125°C or higher, more preferably 130°C or higher, even more preferably 135°C or higher, and particularly preferably 140°C or higher. Furthermore, from the viewpoint of adhesive strength to the adherend, the softening point of the high-softening-point resin is usually preferably 200°C or lower, more preferably 180°C or lower, even more preferably 170°C or lower, and particularly preferably 160°C or lower.

[0245] Specific examples of the high-softening-point resins mentioned above include terpene phenol resins, polymerized rosin, or esterified polymerized rosin. These high-softening-point resins may be used individually or in combination of two or more. It is preferable that the high-softening-point resin includes one or more terpene phenol resins. For example, a terpene phenol resin having a softening point of 120°C to 200°C (e.g., 120°C to 180°C, or 125°C to 170°C) can be used as the high-softening-point resin.

[0246] The terpene phenol resin described above preferably has a softening point of 120°C or higher and a hydroxyl value (OH value) of 40 mg KOH / g or higher (for example, 40 to 200 mg KOH / g, more preferably 40 to 160 mg KOH / g). A hydroxyl value within the above range of the terpene phenol resin can lead to the realization of a higher-performance adhesive tape. The hydroxyl value in this specification is measured by potentiometric titration as specified in JIS K 0070:1992. A more specific measurement method can be found in Japanese Patent Application Publication No. 2014-55235.

[0247] In this disclosure, for example, the rubber-based mixed adhesive is preferably a mixed adhesive obtained by mixing a high softening point resin (h1) with a hydroxyl value of 40 mg KOH / g or more and less than 80 mg KOH / g and a high softening point resin (h2) with a hydroxyl value of 80 mg KOH / g or more (e.g., 80 to 160 mg KOH / g, e.g., 80 to 140 mg KOH / g). In this case, the amount of high softening point resin (h1) and high softening point resin (h2) used is preferably in the mass ratio (h1:h2) range of 1:5 to 5:1, and more preferably in the range of 1:3 to 3:1 (e.g., 1:2 to 2:1). It is preferable that both the high softening point resin (h1) and the high softening point resin (h2) are terpene phenol resins.

[0248] In this embodiment, from the viewpoint of repulsion resistance and holding power, the lower limit of the high softening point resin content is preferably 20 parts by mass or more, 30 parts by mass or more (for example, 35 parts by mass or more) per 100 parts by mass of the base resin. Furthermore, from the viewpoint of adhesive strength or low-temperature characteristics, the upper limit of the high softening point resin content is preferably 100 parts by mass or less, 80 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less per 100 parts by mass of the base resin.

[0249] In this disclosure, the rubber-based mixed adhesive may contain, in place of, or in addition to the high-softening-point resin, a low-softening-point resin having a softening point of less than 120°C. The rubber-based mixed adhesive may also contain a high-softening-point resin having a softening point of 120°C or higher, and a low-softening-point resin having a softening point of less than 120°C.

[0250] As the low softening point resin mentioned above, a resin having a softening point of 40°C or higher (for example, 60°C or higher) is preferred. When considering repulsion resistance or retention strength, a low softening point resin having a softening point of 80°C or higher (more preferably 100°C or higher) and less than 120°C is preferred. Alternatively, a low softening point resin having a softening point of 110°C or higher and less than 120°C may be used.

[0251] In this embodiment, it is preferable that the rubber-based mixed adhesive contains at least one of petroleum resin and terpene resin (e.g., unmodified terpene resin) as the low-softening point resin. For example, it is preferable that the main component of the low-softening point resin (i.e., the component accounting for more than 50% by mass of the low-softening point resin) is petroleum resin, terpene resin, or a mixture of petroleum resin and terpene resin. When adhesion and compatibility are important, it is preferable that the main component of the low-softening point resin is terpene resin (e.g., β-pinene polymer). It is also possible that substantially the entire amount of the low-softening point resin (e.g., 95% by mass or more) is composed of terpene resin.

[0252] The low softening point resin described above is preferably a tackifying resin with a hydroxyl value of 0 or more and less than 80 mgKOH / g. The tackifying resin with a hydroxyl value of 0 or more and less than 80 mgKOH / g may be used individually from among the various tackifying resins described above, or two or more may be used in appropriate combinations. The low softening point resin is preferably, for example, a terpene phenol resin, petroleum resin (e.g., C5 petroleum resin), terpene resin (e.g., β-pinene polymer), rosin-based resin (e.g., polymerized rosin), or rosin derivative resin (e.g., an ester of the polymerized rosin), etc., with a hydroxyl value of 0 or more and less than 80 mgKOH / g.

[0253] When prioritizing adhesion to the adherend, the content of the low softening point resin is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the base resin. Furthermore, when prioritizing resistance to repulsion, the content of the low softening point resin is preferably 120 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, even more preferably 50 parts by mass or less, and particularly preferably 40 parts by mass or less.

[0254] When the tackifying resin is a mixture containing a low softening point resin and a high softening point resin, the mass ratio of the low softening point resin to the high softening point resin is preferably 1:5 to 3:1, and more preferably 1:5 to 2:1. In this disclosure, it is preferable that the rubber-based mixed adhesive contains more high softening point resin than low softening point resin as the tackifying resin, for example, the mass ratio of the low softening point resin to the high softening point resin is preferably 1:1.2 to 1:5. This makes it possible to realize an adhesive tape with higher performance.

[0255] In this disclosure, the content of the tackifying resin per 100 parts by mass of the base resin (e.g., rubber polymer) is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more. Furthermore, when low-temperature characteristics (e.g., adhesive strength and impact resistance under low-temperature conditions) are important, the content of the tackifying resin per 100 parts by mass of the base resin is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 100 parts by mass or less, and particularly preferably 80 parts by mass.

[0256] (Other additives) In this disclosure, the adhesive composition may optionally contain a crosslinking agent. The type of crosslinking agent is not particularly limited and can be appropriately selected from known crosslinking agents. Examples of such crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, and metal chelate-based crosslinking agents. One type of crosslinking agent may be used alone, or two or more types may be used in combination. In particular, from the viewpoint of improving cohesive force, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred. The amount of crosslinking agent used is not particularly limited and can be selected from a range of about 10 parts by mass or less (for example, about 0.005 to 10 parts by mass, preferably about 0.01 to 5 parts by mass) per 100 parts by mass of the base resin (e.g., acrylic polymer).

[0257] The above adhesive composition may contain various known fillers that can be included in adhesives or adhesive resins. Various particulate or fibrous materials may be used as fillers. Examples of materials constituting the particulate material include metals such as copper, nickel, aluminum, chromium, iron, and stainless steel; metal oxides such as alumina, zirconia, and zinc oxide; carbides such as silicon carbide, boron carbide, and nitrogen carbide; nitrides such as aluminum nitride, silicon nitride, and boron nitride; inorganic materials such as calcium carbide, calcium carbonate, aluminum hydroxide, glass, and silica; polymers such as polystyrene, acrylic resin (e.g., polymethyl methacrylate), phenolic resin, benzoguanamine resin, urea resin, silicone resin, polyester, polyurethane, polyethylene, polypropylene, polyamide (e.g., nylon), polyimide, and polyvinylidene chloride. In addition, natural raw material particles such as volcanic ash, clay, and sand may be used as particulate material. Furthermore, the adhesive composition may also contain hollow particulate matter as a filler, i.e., microballoons (for example, hollow particles made of inorganic or organic materials) as described below. Examples of microballoons used in the adhesive composition include glass balloons (e.g., hollow glass balloons), hollow metal oxide balloons (e.g., hollow alumina balloons), and hollow porcelain balloons (e.g., hollow ceramic balloons). As the fibrous material, various synthetic fiber materials or natural fiber materials can be used. These may be used individually or in combination of two or more. The amount of filler added is not particularly limited and can be appropriately selected based on its purpose, application, or common technical knowledge.

[0258] The above adhesive composition may optionally contain various common additives such as leveling agents, crosslinking aids, plasticizers, softeners, colorants (dyes, pigments), antistatic agents, anti-aging agents, UV absorbers, antioxidants, or light stabilizers. Furthermore, adhesive strength modifiers such as silicone oligomers may be added to the adhesive composition (e.g., an acrylic adhesive composition). Such additives can be used by conventional methods if they are known.

[0259] -Adhesive- In this embodiment, an adhesive composed of a vinyl aromatic block copolymer and an adhesive resin may be used as the adhesive resin. The adhesive is preferably a block copolymer formed from at least two blocks selected from the group consisting mainly of a polystyrene block formed from a vinyl aromatic (X block), preferably styrene; a diene polymer block formed mainly by polymerization of a 1,3-diene compound (Y block), such as isoprene or butadiene; and a copolymer block formed by polymerization of both isoprene and butadiene. The block copolymer may also be partially or completely hydrogenated in the diene block. Similarly, a block copolymer of vinyl aromatic and isobutylene can also be used as an adhesive. A preferred adhesive is a block copolymer and has polystyrene end blocks.

[0260] The block copolymer obtained from the X block and the Y block may contain the same or different Y block as each block. The block copolymer may have a linear XYX structure. Radial block copolymers and star-shaped and linear multiblock copolymers can also be used in this embodiment. Furthermore, the XY-block copolymer may be used as an adhesive. These copolymers may be used individually or in combination of two or more types.

[0261] In place of the polystyrene block described above, polymer blocks based on other aromatic-containing homopolymers and copolymers (preferably copolymers polymerized from C8-C12 aromatic compounds) (for example, polymer blocks obtained by polymerizing aromatic compounds having a glass transition temperature of over 75°C) can also be used as X blocks, such as aromatic blocks obtained by polymerizing α-methylstyrene. Furthermore, the same or different A-blocks can also be similarly contained.

[0262] In this embodiment, the X block is also referred to as the “hard block,” and the Y block is also referred to as the “soft block.” This reflects the selection of polymer blocks corresponding to their glass transition temperatures (the X block is at least 25°C, in particular at least 50°C, and the Y block is at most 25°C, in particular at most -25°C).

[0263] In this embodiment, the block copolymer has 10% to 35% by mass, preferably 20% to 32% by mass of polyvinyl aromatic moiety.

[0264] More preferably, the lower limit of the content of vinyl aromatic block copolymer, particularly styrene block copolymer, is at least 20% by mass, preferably at least 30% by mass, and especially preferably at least 35% by mass, based on the total amount of adhesive (100% by mass).

[0265] If the proportion of vinyl aromatic block copolymer is too low, the cohesive force of the adhesive will be relatively weak.

[0266] The upper limit for the content of vinyl aromatic block copolymer, particularly styrene block copolymer, is 80% by mass or less, preferably 65% ​​by mass or less, and most preferably a maximum of 60% by mass or less, relative to the total amount of adhesive (100% by mass). If the content of vinyl aromatic block copolymer is too high, the adhesive will have almost no adhesive properties.

[0267] Block copolymers containing soft and hard blocks with significantly different glass transition temperatures generally form domain structures at room temperature. This tends to generate cohesive forces through physical crosslinking of the adhesive. Furthermore, unmodified block copolymers of styrene blocks and diene / butylene / isobutylene / ethylene / propylene blocks can generally only maintain shear stability up to 85°C or a maximum of 100°C, and within this temperature range, the hard block begins to soften depending on the composition.

[0268] The adhesive may be based on a selected styrene block copolymer. The pressure-sensitive adhesion of the polymer mixture can be achieved by adding an elastomer phase of a miscible adhesive resin. Possible mixed components to be added to the adhesive include anti-aging agents, processing aids, colorants, optical gloss agents, stabilizers, end-block reinforcing resins, and optionally, other polymers that preferably have elastomer properties. The types and amounts of these mixed components can be selected as needed.

[0269] From the viewpoint of increasing the desired cohesiveness, the adhesive may have at least one adhesive resin in addition to at least one vinyl aromatic block copolymer. The adhesive resin is preferably compatible with the elastomer block of the block copolymer. Particularly preferable is that, with respect to the total adhesive resin, at least 75% by mass is a hydrocarbon resin, a terpene resin, or a mixture thereof.

[0270] Examples of adhesion-imparting agents for adhesives include non-polar hydrocarbon resins. Preferably, these non-polar hydrocarbon resins include hydrogenated or unhydrogenated polymers of dicyclopentadiene, unhydrogenated, partially, selectively, or fully hydrogenated hydrocarbon resins based on C5-, C5 / C9-, or C9- monomer streams, and polyterpene resins based on α-pinene and / or β-pinene and / or δ-limonene. These adhesive resins may be used alone or as a mixture of two or more. In this case, they can be used as both solid and liquid resins at room temperature. Since hydrogenated or unhydrogenated rosin-based resins are utilized in the adhesive up to a maximum of 25% based on the total amount of resin, the adhesive will not become excessively polar.

[0271] As further additives, the following components (a) to (h) may generally be used. Component (a): For example, a plasticizer such as a softening oil, or a low molecular weight liquid polymer such as low molecular weight polybutene. Component (b): Primary antioxidant such as sterically hindered phenol. Component (c): Secondary antioxidants such as phosphates or thioethers, for example. Component (d): Process stabilizers such as C-radical scavengers, for example. Component (e): For example, a photoprotective agent such as a UV absorber or a sterically hindered amine. Ingredient (f): Process aid Ingredients (g): End block reinforcing resin, Component (h): possibly other polymers with elastomeric properties, appropriately available elastomers, in particular unsaturated polydienes such as natural or synthetic polyisoprene or polybutadiene, which are based on pure hydrocarbons, substantially chemically saturated elastomers (e.g., saturated ethylene-propylene copolymers, α-olefin copolymers, polyisobutylene, butyl rubber, ethylene-propylene rubber), and chemically functionalized hydrocarbons (e.g., allyl polyolefins containing halogenated acrylates or vinyl ether-containing polyolefins).

[0272] The above adhesive may be colored using a coloring agent or pigment as necessary, and the color of the adhesive may be white, black, or chromatic.

[0273] In this embodiment, the adhesive resin may be an adhesive resin comprising an elastomer (i) based on at least one polyvinyl aromatic-polydiene-block copolymer, an adhesive resin (ii) containing at least one adhesive resin, an optionally added softening resin (iii), and an optionally added other additive (iv).

[0274] The above elastomer (i) preferably consists of a polyvinyl aromatic-polydiene-block copolymer, particularly a polyvinyl aromatic-polybutadiene-block copolymer, for at least 90% by mass. The proportion of polyvinyl aromatics in the polyvinyl aromatic-polydiene-block copolymer is 12 to 35% by mass, preferably 20 to 32% by mass. The blending ratio of elastomer (i) to the total amount of adhesive resin (100% by mass) is preferably 40 to 55% by mass, more preferably 45 to 55% by mass. Furthermore, it is preferable that the adhesive resin (ii) consists of a hydrocarbon resin that is essentially compatible with the polydiene block and essentially incompatible with the polyvinyl aromatic block, preferably in an amount of 90% by mass or more, and more preferably 95% by mass or more. The blending ratio of the adhesive resin (ii) to the total amount of adhesive resin (100% by mass) is preferably at least 40% by mass, and more preferably 40 to 60% by mass. Furthermore, the amount of softening resin (iii) relative to the total amount of adhesive resin (100% by mass) is 0% to a maximum of 5% by mass. Furthermore, the adhesive resin may contain microballoons (for example, microballoons described later). When microballoons are included, the proportion of microballoons to the total amount of adhesive resin (100% by mass) is preferably at least 0.5% by mass, more preferably 0.5 to 2.5% by mass, and even more preferably 1.0 to 2.0% by mass. Furthermore, when an adhesive resin is used as the adhesive layer, the thickness of the adhesive layer is preferably 20 to 75 μm, and more preferably 25 to 65 μm.

[0275] The adhesive resin in this embodiment includes a pressure-sensitive adhesive based on elastomer (i) (for example, at least one polyvinyl aromatic-polydiene-block copolymer) and at least one adhesive resin (ii).

[0276] The above elastomer (i) is XY, XYX, (XY) n (XY)n Z or (XYX) n Preferably, it is at least one polyvinyl aromatic-polydiene-block copolymer in the form of a block copolymer having the Z structure. Note that XY, XYX, (XY) n (XY) n Z or (XYX) n In Z, X independently represents polymer blocks formed by the polymerization of at least one vinyl aromatic compound, Y independently represents polymer blocks formed by the polymerization of conjugated dienes having 4 to 18 carbon atoms, or partially hydrogenated derivatives of such polymers in a polydiene block, Z represents the remainder of the coupling reagent or polymerization initiator, and n represents an integer of 2 or more.

[0277] The adhesive resin is preferably composed of synthetic rubber, and it is particularly preferable that all synthetic rubbers constituting the adhesive resin are block copolymers having the above-described structure. Therefore, the adhesive resin may contain a mixture of different block copolymers having the above-described structure.

[0278] In other words, the above block copolymer (vinyl aromatic block copolymer) comprises one or more rubber-like blocks Y (also referred to as soft blocks) and one or more glass-like blocks X (also referred to as hard blocks). Particularly preferably, at least one synthetic rubber constituting the adhesive resin is a block copolymer having the composition XY, XYX, (XY)2Z, (XY)3Z, or (XY)4Z, where the above-described meanings apply to X, Y, and Z. A particularly preferred form of the adhesive resin is a block copolymer in which all synthetic rubber constituting the adhesive resin has the composition XY, XYX, (XY)2Z, (XY)3Z, or (XY)4Z. The above-described meanings apply to X, Y, and Z. In particular, the synthetic rubber of the adhesive resin is preferably a mixture of block copolymers having the configurations XY, XYX, (XY)2Z, (XY)3Z, or (XY)4Z, and more preferably contains at least a diblock copolymer (excluding the above general formula (V)) XY and / or a triblock copolymer (excluding the above general formula (I)) XYZ or (XY)2X.

[0279] Furthermore, diblock and triblock copolymers (excluding the above general formulas (I) and (V)), and (XY) n - or (XY) n A mixture consisting of Z-block copolymers (where n is 3 or greater) is preferable.

[0280] Furthermore, diblock copolymers (excluding the above general formula (V)) and radial multiblock copolymers (XY) n or (XY) n A mixture consisting of Z (where n is 3 or greater) is favorable.

[0281] The adhesive resin of this embodiment preferably uses a pressure-sensitive adhesive based on a block copolymer comprising a polymer block X (X block) mainly formed from vinyl aromatics, preferably styrene, and a polymer block Y (Y block) mainly formed from 1,3-dienes, such as butadiene and isoprene, or copolymers of both, particularly butadiene polymerization. In this case, these products may be partially hydrogenated in the diene block. Among the partially hydrogenated derivatives, block copolymers in which any vinyl groups, i.e., repeating units present in an unsaturated state in the side chains, such as 1,2-polybutadiene, 1,2-polyisoprene, or 3,4-polyisoprene, are present in a hydrogenated state are particularly suitable. Preferably, the block copolymer of the adhesive resin has polystyrene-terminated blocks.

[0282] The block copolymer resulting from the X block and the Y block may contain the same or different Y blocks. The block copolymer may have a linear XYX structure. Similarly, radial block copolymers, as well as star-shaped and linear multiblock copolymers, may also be used. Other components may include a binary XYZ block copolymer. All of the above polymers can be used individually or as mixtures of each other.

[0283] Instead of the preferred polystyrene block described above, polymer blocks based on other aromatic compounds (preferably C8-C12 aromatic compounds) having a glass transition temperature above 75°C, such as α-methylstyrene-containing aromatic blocks, can also be used as vinyl aromatics. Furthermore, the same or different X blocks may also be included.

[0284] The vinyl aromatics for the composition of the X block preferably include styrene, α-methylstyrene, and / or other styrene derivatives. Therefore, the X block may exist as a homopolymer or copolymer. Polystyrene is a particularly preferred X block.

[0285] The preferred conjugated dienes as monomers for the composition of soft block Y are preferably selected from the group consisting of butadiene, isoprene, ethyl butadiene, phenyl butadiene, piperylene, pentadiene, hexadiene, ethylhexadiene, and dimethyl butadiene, as well as any mixtures thereof. Soft block Y may also exist as a homopolymer or copolymer.

[0286] The conjugated diene used as the monomer in the flexible block Y is particularly preferably selected from butadiene and isoprene. For example, the flexible block Y is a polymer made of polyisoprene, polybutadiene, or partially hydrogenated derivatives of polymers of both, such as polybutylene butadiene in particular; or a mixture of butadiene and isoprene. Most preferably, block B is polybutadiene.

[0287] The selection of blocks for "hard block X" and "soft block Y" reflects their respective glass transition temperatures (the glass transition temperature of hard block X is 25°C or higher, more preferably 50°C; on the other hand, the glass transition temperature of soft block Y is preferably 25°C or lower, more preferably -25°C or lower).

[0288] In this embodiment, the lower limit of the proportion of vinyl aromatic block copolymer, particularly styrene block copolymer, is at least 40% by mass, preferably at least 45% by mass, relative to the total amount (100% by mass) of the adhesive resin. The lower the proportion of vinyl aromatic block copolymer, the weaker the cohesive force of the adhesive resin becomes, resulting in easier separation during delamination. In addition, the glass transition temperature of the elastomer phase increases, reducing impact resistance. Furthermore, the risk of residue remaining on the adhesive substrate during delamination also increases.

[0289] On the other hand, the upper limit of the proportion of vinyl aromatic block copolymer, particularly styrene block copolymer, is preferably 55% by mass in total with respect to the total amount of adhesive resin. Conversely, the higher the proportion of vinyl aromatic block copolymer, the less pressure-sensitive the adhesive becomes.

[0290] In this embodiment, the proportion of vinyl aromatic block copolymer, particularly styrene block copolymer, is at least 40% by mass, more preferably 45-55% by mass, relative to the total amount of adhesive resin (100% by mass).

[0291] The adhesive resin may include, in addition to at least one vinyl aromatic block copolymer, at least one adhesive resin (ii) to enhance the adhesiveness to a desired level. Preferably, the adhesive resin (ii) is compatible with the elastomer block of the block copolymer.

[0292] "Adhesive resin" is understood to be consistent with the general understanding of those skilled in the art, and refers to oligomeric or polymeric resins that enhance the adhesive properties (tack, intrinsic tackiness) of an adhesive compared to other adhesives that are otherwise identical, although they do not include adhesive resins.

[0293] In this embodiment, the adhesive resin is selected in a proportion of 90% or more by mass, preferably 95% or more by mass (based on the total resin proportion), which has a DACP (diacetone alcohol cloud point) of more than +5°C, preferably more than +10°C and less than +65°C (when polyisoprene-block copolymer is present in the elastomer), and preferably less than +50°C (when polyisoprene-block copolymer is not present in the elastomer). In addition, at least one resin has an MMAP (mixed methylcyclohexaneaniline point) of at least +50°C, preferably at least +60°C and up to +100°C (when polyisoprene-block copolymer is present in the elastomer), and preferably up to +90°C (when polyisoprene-block copolymer is not present in the elastomer). At least one adhesive resin has a softening point (ring-spherical type) of 70°C or higher, preferably 100°C or higher and up to 150°C.

[0294] The tackifier used in combination with the adhesive resin described above is preferably a non-polar hydrocarbon resin, such as a hydrogenated or non-hydrogenated polymer of dicyclopentadiene, an unhydrogenated or partially, selectively, or fully hydrogenated hydrocarbon resin based on a C5-, C5 / C9-, or C9- monomer stream, or a polyterpene resin based on α-pinene and / or β-pinene and / or δ-limonene. The aforementioned adhesive resins can be used alone or in mixtures. In some cases, a hydrogenated or non-hydrogenated adhesive resin containing oxygen may be used, preferably in a proportion of up to 10% of the total amount of resin in the adhesive resin.

[0295] In this embodiment, it is particularly preferable that the adhesive resin (based on the total resin proportion) comprises at least 75% by mass of a hydrocarbon resin, a terpene resin, or a mixture thereof. The adhesive resin contains at least one adhesive resin in an amount of preferably 40 to 60% by mass relative to the total amount of adhesive resin (100 by mass).

[0296] In this embodiment, the blending ratio of the (viscous) softening resin (iii) at room temperature is up to a maximum of 5% by mass relative to the total amount (100% by mass) of the adhesive resin. However, the (viscous) softening resin (iii) does not need to be blended at room temperature. For example, the use of low-viscosity softeners such as mineral oil and vegetable oil can be significantly avoided. When using the softening resin (iii), a viscous softening resin having a melt viscosity of at least 25 Pa*s, particularly at least 50 Pa*s, and a softening temperature of <25°C at 25°C and 1 Hz is preferred. The melt viscosity is determined according to Test VI.

[0297] The above adhesive resin may optionally contain other additives (iv). For example, components (b) to (h) above may be used as such other additives (iv). The above component (b) is preferably blended in a ratio of 0.2 to 1% by mass, based on 100% by mass of the total amount of the adhesive resin. Component (c) may include secondary antioxidants such as phosphites, thioesters, or thioethers, and it is preferable that component (c) is blended in a ratio of preferably 0.2 to 1% by mass based on 100% by mass of the total amount of the adhesive resin. The above component (d) is preferably blended in a ratio of 0.2 to 1% by mass relative to the total amount (100% by mass) of the adhesive resin. The above component (e) is preferably blended in a ratio of 0.2 to 1% by mass relative to the total amount (100 by mass) of the adhesive resin. Component (f) is preferably blended in a ratio of 0.2 to 1% by mass relative to the total amount (100% by mass) of the adhesive resin. The component (g) is preferably blended in a ratio of 0.2 to 10% by mass relative to the total amount of adhesive resin (100% by mass). Component (h): In some cases, a further polymer, preferably of elastomeric properties, in a proportion of preferably 0.2 to 10% by mass based on the total amount (100% by mass) of the adhesive resin; correspondingly, available elastomers include, among others, elastomers based on pure hydrocarbons, such as unsaturated polydienes such as natural or synthetic polyisoprene or polybutadiene; chemically substantially saturated elastomers, such as saturated ethylene-propylene copolymers, α-olefin copolymers, polyisobutylene, butyl rubber, ethylene-propylene rubber; and chemically functionalized hydrocarbons, such as halogen-containing, acrylate-containing, allyl-containing, or vinyl ether-containing polyolefins.

[0298] The types and amounts of the mixed components of the other additives mentioned above can be selected as needed. If additive (iv) is used and is migratory, additives of the same type as (iv) can be used in the same way. The adhesive resin does not have to contain some, preferably all, of the other additives mentioned above.

[0299] In this embodiment, the adhesive resin may further contain additives other than those described above. These additional additives are not particularly limited and include, for example, crystalline or amorphous oxides, hydroxides, carbonates, nitrides, halides, carbides, or mixed oxide- / hydroxide- / halide compounds of aluminum, silicon, zirconium, titanium, tin, zinc, iron, or alkali (earth) metals. These additional additives may also be aluminiums, such as aluminum oxides, boehmite, bayerite, gibbsite, diaspore, and similar materials. Particularly preferred examples are layered silicates, such as bentonite, montmorillonite, hydrotalcite, hectorite, kaolinite, boehmite, mica, vermiculite, or mixtures thereof. Furthermore, carbon black or other transformations of carbon, such as carbon nanotubes, can also be used as additives.

[0300] Furthermore, the adhesive resin may be colored using dyes or pigments as needed. The color of the adhesive resin may be, for example, white, black, or chromatic.

[0301] When considering the adjustment of the thermal shear strength of the adhesive resin, silica, more preferably precipitated silica surface-modified with dimethyldichlorosilane, may be added.

[0302] The adhesive layer of this embodiment may contain microballoons. The microballoons in the adhesive layer have a number-average primary particle size of 10 to 60 μm. On the other hand, the microballoons used as raw materials when preparing the adhesive composition have an average particle size of 10 to 50 μm. When microballoons with a predetermined number-average primary particle size are present in the adhesive layer, numerous cavities or shear yields are generated near the microballoons dispersed in the matrix, absorbing energy during impact, thus improving impact resistance. However, if the filling rate of microballoons in the adhesive layer is increased to prioritize the required impact resistance, the elastic modulus improves, and cut processability improves, but the relative amount of adhesive resin decreases, resulting in a decrease in adhesive performance. This tendency is particularly pronounced when using adhesive tape with an adhesive layer and a base layer, as it causes poor anchoring of the adhesive layer to the base layer. However, when the above-mentioned filler particles and microballoons are added to the adhesive layer in combination, high adhesive strength can be maintained while ensuring impact resistance. The reason for this is not clear, but it is thought that when filler particles and microballoons of different particle sizes and materials are mixed, aggregation of fillers or balloons is suppressed by each other, resulting in a better dispersion state in the adhesive layer.

[0303] The microballoon in this embodiment is a hollow body, and the average particle size (=outer diameter) of the hollow body alone is 10 to 50 μm. The microballoon may also contain volatile hydrocarbons such as butane or isobutane, if necessary. Note that the average particle size (=outer diameter) of the hollow body (alone) of 10 to 50 μm refers to the average particle size after the microballoon has expanded. When adding the microballoons in this embodiment to the adhesive composition, it is preferable to use inflated microballoons that have been pre-inflated by heat treatment or the like, rather than uninflated microballoons. Alternatively, when forming a precursor for the adhesive layer (such as a coating of the adhesive layer resin composition) or the adhesive layer using uninflated microballoons, the microballoons may be inflated. Examples of uninflated microballoons include uninflated microballoons made of thermoplastic resin.

[0304] On the other hand, the number-average primary particle diameter of the microballoons present in the adhesive layer also represents the outer diameter after the microballoons have expanded. In this embodiment, the microballoons included in the adhesive layer may be hollow bodies with a number-average primary particle diameter of 10 to 60 μm, and it is preferable that they are already expanded microballoons.

[0305] In this embodiment, the average particle size of the microballoons added to the adhesive composition after inflation is preferably 10 to 50 μm, more preferably 15 to 50 μm, and even more preferably 18 to 45 μm. When the average particle size of the microballoons is within this preferred range, the adhesive tape can be peeled off more easily and quickly, it is less likely to tear even when the thickness of the adhesive tape substrate is thin, and it exhibits excellent impact resistance, shear adhesion, and splitting adhesion. On the other hand, if the average particle size of the microballoons is less than 10 μm, the desired impact resistance cannot be obtained, and if it exceeds 50 μm, the adhesive performance such as shear adhesion and splitting adhesion may be impaired. In this specification, "average particle size of microballoons" refers to the size of individual microballoon particles before they are added to the adhesive composition, and is the volume-average particle size measured using a laser diffraction scattering device (Microtrac). The average particle size of the microballoons was measured using the measurement conditions described in the Examples section below.

[0306] In this specification, "number-average primary mean particle diameter of microballoons" refers to the size of individual microballoon particles present in the adhesive layer, and the number-average primary mean particle diameter of microballoons present in the adhesive layer is measured using the following method. First, an adhesive tape cooled under liquid nitrogen was randomly cut in three places using a microtome, and three fragments were taken as samples. Then, a 400x magnification photograph was taken of each sample using a scanning electron microscope, and from the three photographs taken, hollow particles were identified as microballoons and solid particles as filler particles. Subsequently, the cross-sectional areas of the hollow and solid particles, calculated by binarization processing (e.g., Otsu's binarization process) using image analysis software, were considered as the area of ​​a circle, and the equivalent circle diameter of the hollow and solid particles was measured. Then, the total number of hollow and solid particles in the three photographs and their corresponding equivalent circle diameters were calculated, and the number-average primary mean particle diameter of the hollow microballoons was calculated from the following formula (B).

number

[0307] In this embodiment, the external shape of the microballoon is not particularly limited and can be appropriately selected depending on the purpose, and examples include spherical, elliptical, polygonal, cubic, rod-shaped, needle-shaped, plate-shaped, scale-shaped, or irregular shapes.

[0308] In this embodiment, the microballoon has a sealed structure with an outer shell. Either a microballoon using an organic material (e.g., thermoplastic resin) or an inorganic material (e.g., borosilicate glass, silica, carbon, ceramic, etc.) for its outer shell can be used, but an organic microballoon is preferred. When using an organic microballoon, the outer shell softens, particularly when heat is applied to it. Simultaneously, the liquid foaming agent gas sealed inside the hollow body changes to a gaseous state. During this process, the microballoon irreversibly expands and inflates three-dimensionally. Expansion ends when the internal and external pressures become equal. Since the outer shell is maintained, a closed-cell foam can be obtained.

[0309] In this embodiment, it is preferable that the microballoons included in the adhesive layer are inflated microballoons. Furthermore, in this embodiment, in the adhesive composition that forms the adhesive layer, uninflated microballoons are used to form the adhesive layer. Examples of such uninflated microballoons include uninflated microballoons made of thermoplastic resin. In this embodiment, microballoons are preferably those in which the outer shell surface layer is made of the first resin. More specifically, the preferred microballoons in this embodiment are preferably hollow particles having a surface layer containing the first resin.

[0310] The first resin described above is preferably a thermoplastic resin. Furthermore, the first resin is preferably an acrylonitrile-based resin, and specific examples include vinylidene chloride / acrylonitrile copolymer, methyl methacrylate / acrylonitrile copolymer, methacrylonitrile / acrylonitrile copolymer, and the like. Specific examples of the above microballoons include the Dualite® series from Dualite Corporation, the Expancel series from Akzo Nobel, the Matsumoto Microsphere® series from Matsumoto Oil & Fat Pharmaceutical Co., Ltd., hollow glass particles (silica balloons, alumina balloons, etc.), and hollow ceramic particles.

[0311] In this embodiment, it is preferable to coat part or all of the surface of the microballoons with an inorganic material (e.g., inorganic fine particles). The inorganic material is preferably at least one or more inorganic powders selected from the group consisting of calcium carbonate, surface-treated calcium carbonate, titanium dioxide, silicon dioxide, talc, clay, and carbon black. Surface coating of the microballoons with an inorganic material is preferable from the viewpoint of improving productivity, dispersibility, and impact resistance. Furthermore, the inorganic material may be surface-treated with a titanate-based coupling agent or an aluminate-based coupling agent as needed. The microballoons used in this embodiment are hollow particles having a surface layer containing a first resin, and it is preferable that an inorganic material is attached to the surface of the surface layer. Furthermore, in this embodiment, it is preferable that calcium carbonate is attached to part or all of the surface of the microballoons. This further improves the impact resistance effect.

[0312] In this embodiment, the ratio of the number-average primary particle diameter of microballoons to the average thickness of the adhesive layer is not particularly limited and can be appropriately selected according to the purpose. The ratio of the number-average primary particle diameter of microballoons to the thickness of the adhesive layer, expressed as [number-average primary particle diameter of microballoons / average thickness of the adhesive layer], is preferably in the range of 0.1 to 1.0, more preferably 0.2 to 0.9, even more preferably 0.2 to 0.8, and particularly preferably 0.3 to 0.7. A ratio of 0.1 or higher makes it easier to obtain suitable impact resistance, and a ratio of 1.0 or lower is advantageous in that adhesive performance such as shear adhesion and splitting adhesion is also better.

[0313] The microballoon content in the adhesive layer is 1 to 30 parts by mass per 100 parts by mass of adhesive resin, preferably 2 to 25 parts by mass, more preferably 3 to 23 parts by mass, and even more preferably 4 to 20 parts by mass. By having a microballoon content of 1 part by mass or more per 100 parts by mass of adhesive resin, it is possible to ensure both impact resistance and cutability, or ease of peeling. Furthermore, by having a microballoon content of 50 parts by mass or less per 100 parts by mass of adhesive resin, it is possible to prevent the adhesive layer from remaining on the adherend, a decrease in impact resistance, and a decrease in shear adhesion or splitting adhesion. The microballoon content in the adhesive layer can be adjusted as appropriate when preparing the adhesive composition.

[0314] The volume ratio of microballoons to the total volume of the adhesive layer is preferably 3 to 40 vol%, more preferably 5 to 35 vol%, even more preferably 8 to 30 vol%, and most preferably 10 to 30 vol%. A microballoon volume ratio of 3 vol% or more allows the adhesive tape to be removed more easily and quickly. Furthermore, a microballoon volume ratio of 40 vol% or less prevents the adhesive layer from remaining on the adherend, reduces impact resistance, and prevents a decrease in shear or splitting adhesive strength.

[0315] The volume ratio of microballoons to the adhesive layer in this specification can be calculated using the following formulas (4) to (6). Adhesive resin *1 Mass A(g) / adhesive resin *1 Density A (g / cm³) 3 ) = adhesive resin *1 Volume A(cm³) 3 )...Equation (4) Microballoon mass B (g) / Microballoon density B (g / cm³) 3 ) = Volume B of the microballoon (cm³) 3 )...Equation (5) Volume B of a microballoon (cm³)3 ) / (Adhesive resin *1 Volume A(cm³) 3 ) + Volume B of the microballoon (cm³) 3 )) × 100 = Volume percentage of microballoons (volume %) ... Equation (6) In addition, in formulas (4) and (6) above, the adhesive resin represented by *1 may contain other components as described below. The above density values ​​were measured in accordance with JIS Z 8804.

[0316] <Foam layer> In the first embodiment, the adhesive tape comprises a foam layer, the foam of the foam layer having a 25% compressive strength of 40 to 160 kPa and a tensile strength of 3.0 to 15.0 MPa. This imparts appropriate elasticity to the adhesive tape, allowing it to continue to adhere to each component (first component, second component) even if there is slight distortion in the component (adherent) (having resistance to peeling in the tape thickness direction).

[0317] In the first embodiment, the foam in the foam layer has a 25% compressive strength of 40 to 160 kPa, preferably 50 to 140 kPa, and more preferably 60 to 130 kPa. By using a foam with a 25% compressive strength within this range, excellent adhesion to the adherend is achieved, and it conforms well to adherends with uneven shapes or rough surfaces. Furthermore, because the foam with this compressive strength has appropriate cushioning properties, the pressure during application is concentrated at the joint, easily pushing out air present at the adhesive interface. Therefore, even when joining rigid bodies, excellent adhesion can be achieved without creating gaps that could allow water to enter, for example.

[0318] The foam in the foam layer preferably has a closed-cell structure. This allows for more reliable sealing of the space between the first and second adherends, for example, when bonded together using adhesive tape, thereby improving airtightness and effectively preventing water from seeping in from the cut surface of the foam. The shape of the cells forming the closed-cell structure is not particularly limited, but closed cells with a shape in which the average cell diameter in the flow direction, width direction, or both is longer than the average cell diameter in the thickness direction of the foam are preferred because they have appropriate cushioning properties.

[0319] The average bubble diameter in the thickness direction of the foam is preferably 1 to 100 μm, more preferably 10 to 50 μm, and the average bubble diameter in the flow direction and width direction of the foam is preferably 1.2 to 700 μm, more preferably 10 to 500 μm, and even more preferably 50 to 300 μm. By setting the average bubble diameter within this range, closed cells can be easily formed even when the width of the adhesive tape is narrowed, and the water infiltration path from the cross-section of the foam can be effectively blocked.

[0320] The ratio of average bubble diameters is not particularly limited, but the ratio of the average bubble diameter in the flow direction of the foam to the average bubble diameter in the thickness direction of the foam (average bubble diameter in the flow direction / average bubble diameter in the thickness direction) is preferably 1.2 to 15, and more preferably 3 to 8. Furthermore, the ratio of the average bubble diameter in the width direction of the foam to the average bubble diameter in the thickness direction of the foam (average bubble diameter in the width direction / average bubble diameter in the thickness direction) is preferably 1.2 to 15, and more preferably 3 to 8. It is even more preferable that both the flow direction and the width direction are within the above ratio range. If the ratio is 1.2 or higher, flexibility in the thickness direction is easier to ensure, thus improving conformability. If it is 15 times or less, variations in the flexibility and tensile strength of the foam in the flow direction and width direction are less likely to occur.

[0321] Furthermore, the ratio of the average bubble diameter in the flow direction to the average bubble diameter in the width direction is preferably 0.25 to 4 times, and more preferably 0.33 to 3 times, when the flow direction is set to 1. Within this ratio range, variations in the flexibility and tensile strength of the foam in the flow direction and width direction are less likely to occur.

[0322] The average bubble diameter in the width direction and flow direction of the foam is measured as follows: First, the foam is cut into 1 cm sections in both the width direction and the flow direction. Next, the central portion of the cut surface of the foam is magnified 50 times using a scanning electron microscope (SEM), and then the cross-section in the width direction or flow direction of the foam is photographed so that the entire length of the foam's thickness is captured in the photograph. In the obtained photographs, the diameter of all bubbles present in the 2 mm section of the cut surface before magnification in the flow direction or width direction is measured, and the average bubble diameter is calculated from the average value.

[0323] The average bubble diameter in the thickness direction of the foam is measured as follows: First, measure the thickness of the foam to be photographed with a scanning electron microscope (SEM). Next, take SEM photographs under the same conditions as for measuring the average bubble diameter in the flow direction of the foam. Then, visually count the number of bubbles in the thickness direction at any point in the foam in the obtained photographs, and calculate the average bubble diameter in the thickness direction using the following formula. Average bubble diameter in the thickness direction (μm) = Foam thickness (μm) / Number of bubbles This measurement is taken at three arbitrary locations, and the average value is taken as the average bubble diameter in the thickness direction.

[0324] The foam structure of the foam is preferably configured with a foaming ratio of 2 to 6.5 times, and more preferably 3 to 5.5 times, as this allows for adjustment of compressive and tensile strength within the above ranges, making it easier to achieve excellent adhesion to the adherend. In this specification, the foaming ratio refers to the ratio obtained by dividing the specific gravity of the resin constituting the foam by the specific gravity of the foam itself.

[0325] For the 25% compressive strength, the sample is cut into 50mm squares and stacked until it reaches a thickness of approximately 10mm. The sample is then sandwiched between plates with a larger surface area and compressed at a speed of 10mm / min at 23°C until it reaches approximately 2.5mm (25% of its original thickness). The machine is then stopped, and the strength is measured after 20 seconds.

[0326] The compressive and tensile strengths of the foam can be adjusted as appropriate depending on the material and foam structure used. The type of foam is not particularly limited as long as it has the above-mentioned compressive and tensile strengths, but polyolefin foams made of polyethylene, polypropylene, ethylene-propylene copolymer polymer, ethylene-vinyl acetate copolymer polymer, etc., polyurethane foams, rubber foams made of acrylic rubber or other elastomers can be used, and among these, polyolefin foams can be preferably used because they are easy to produce thin foams with excellent conformability to the unevenness of the adherend surface and excellent cushioning and absorption properties.

[0327] The thickness of the foam can be adjusted as appropriate depending on the application, but it is preferably 50 to 1200 μm. For fixing components of electronic devices, especially small, thin portable electronic devices, a thin tape thickness is required, so the thickness of the foam is more preferably 50 to 300 μm, even more preferably 50 to 250 μm, and most preferably 75 to 150 μm.

[0328] Furthermore, the tensile strength of the foam is 3.0 to 15.0 MPa, preferably 4.0 to 13.0 MPa, and more preferably 5.0 to 12.0 MPa. The elongation at break is 100 to 1000%, preferably 300 to 700%. By using a foam with tensile strength and elongation at break within this range, it is possible to suppress deterioration of processability, tearing, and reduction in application workability of the adhesive tape, even with a flexible foamed foam.

[0329] The aforementioned tensile strength is the maximum strength measured using a Tensilon tensile testing machine on a sample with a gauge length of 2 cm and a width of 1 cm, under measurement conditions of 23°C and 50% RH, and a tensile speed of 300 mm / min.

[0330] Examples of such foams include crosslinked polyolefin resin foams, which are obtained by irradiating a foamable polyolefin resin sheet, formed using a polyolefin resin, with an electron beam to crosslink the resin, and then foaming the sheet. Conventional polyolefin resins can be used, but those containing 40% by mass or more of a polyethylene resin obtained using a metallocene compound containing a tetravalent transition metal are preferred.

[0331] The foam may be subjected to surface treatments such as corona treatment, flame treatment, plasma treatment, hot air treatment, ozone / ultraviolet treatment, or application of an easy-adhesion treatment agent to improve adhesion with the adhesive layer or other layers. Good adhesion with the adhesive can be obtained by surface treatment to achieve a wetting index of 36 mN / m or higher, preferably 40 mN / m, using a wetting reagent.

[0332] <Other layers> In the adhesive tape of the first embodiment, there are no particular limitations, and other layers may be provided as appropriate depending on the purpose, such as a primer layer, an antistatic layer, a non-combustible layer, a decorative layer, a conductive layer, a thermal conductive layer, a release layer, and so on.

[0333] <Shape, characteristics, etc. of adhesive tape> The adhesive tape of the first embodiment is not particularly limited in shape and dimensions, and includes, for example, adhesive tape having a shape and dimensions suitable for being attached to a predetermined substrate (e.g., adhesive tape in a die-cut state) and long sheets of adhesive tape (e.g., adhesive tape before being processed into a specific shape). Furthermore, in the adhesive tape of the first embodiment, a non-adhesive gripping area can be arbitrarily provided, for example, by covering the adhesive layer on the surface side of the adhesive tape with a non-adhesive film or the like, or by leaving the adhesive layer on the surface side absent (by peeling it off or not forming it from the time of manufacture), for the purpose of attaching it to an object or peeling it off an object.

[0334] There are no particular restrictions on the thickness of the adhesive tape, and it can be appropriately selected depending on the thickness of the adhesive layer and the first substrate layer, but it is preferably 85 μm to 2400 μm, more preferably 130 μm to 840 μm, even more preferably 150 μm to 570 μm, and particularly preferably 180 μm to 500 μm. In this specification, "thickness of adhesive tape" refers to the average value of the thickness of any five points on the adhesive tape measured using the TH-104 paper and film thickness measuring instrument (manufactured by Tester Sangyo Co., Ltd.).

[0335] The adhesive tape also has excellent impact resistance. Impact resistance can be confirmed, for example, by the method described in "Evaluation of Impact Resistance" in the Examples section described later. In the evaluation of impact resistance, the height of the impact point at which the adhesive tape peels or breaks can be appropriately selected within a range that does not impair the effects of the present invention, but it is preferably 30 cm or more, more preferably 40 cm or more, even more preferably 50 cm or more, and particularly preferably 60 cm or more. If the height is less than 30 cm, sufficient impact resistance tends not to be obtained.

[0336] The 180° peel adhesive strength of the adhesive tape is not particularly limited and can be appropriately selected depending on the purpose, but 10N / 20mm to 50N / 20mm is preferred, 15N / 20mm to 45N / 20mm is more preferred, and 18N / 20mm to 40N / 20mm is even more preferred. When the 180° peel adhesive strength is within the above preferred range, the adhesive tape has appropriate adhesive strength without causing peeling or shifting from the adherend, and can be easily peeled off when stretched and re-peeled. The 180° peel adhesive strength of adhesive tape refers to the value measured in accordance with JIS Z 0237.

[0337] <Method for manufacturing adhesive tape> In the first embodiment, the method for manufacturing the adhesive tape is not particularly limited and can be appropriately selected from known methods. The method for manufacturing the adhesive tape of the first embodiment preferably includes an adhesive layer formation step, a first substrate layer formation step, a foam layer formation step, and a lamination step, and may further include other layer formation steps as needed. It can also be manufactured by a multilayer simultaneous formation step in which the adhesive layer formation step and the first substrate layer formation step are performed simultaneously.

[0338] The adhesive layer formation process is not particularly limited as long as it can form each adhesive layer, and can be appropriately selected according to the purpose. Examples include forming the adhesive layer on the surface of the release sheet by methods such as heat pressing, casting by extrusion molding, uniaxial stretching, sequential secondary stretching, simultaneous biaxial stretching, inflation, tubing, calendering, and solution methods. Among these, casting by extrusion molding and solution methods are preferred. There are no particular restrictions on the release sheet, and it can be appropriately selected according to the purpose. Examples include paper such as kraft paper, glassine paper, and fine paper; resin films such as polyethylene, polypropylene (biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP)), and polyethylene terephthalate (PET); laminated paper obtained by laminating the paper and the resin film; and paper treated with a sealant such as clay or polyvinyl alcohol, with one or both sides treated with a release agent such as a silicone resin. These may be used individually or in combination of two or more types.

[0339] The first base material layer formation step is not particularly limited as long as it can form the first base material layer, and can be appropriately selected according to the purpose. Examples include the heat press method, the casting method by extrusion molding, the uniaxial stretching method, the sequential secondary stretching method, the simultaneous biaxial stretching method, the inflation method, the tubing method, the calendering method, and the solution method. These methods may be used individually or in combination of two or more. Among these, the casting method by extrusion molding, the inflation method, the tubing method, the calendering method, and the solution method are preferred for imparting suitable flexibility and extensibility to the first base material layer. Furthermore, the first base material layer may be surface-treated to further improve its adhesion to the adhesive layer. There are no particular restrictions on the surface treatment method, and any known method can be appropriately selected as long as it does not impair the properties of the adhesive tape. Examples include sandblasting, surface polishing / friction, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet irradiation treatment, and oxidation treatment.

[0340] In the foam layer formation process, there are no particular restrictions as long as a foam layer can be formed, and the process can be appropriately selected according to the purpose. Specifically, in the foam layer formation process, for example, raw materials for forming the foam are supplied so as to be applied onto a release sheet. If, for example, a material that is foamed after application is used as the raw material, another release sheet is supplied from above onto the surface of the casting raw material. Then, by passing the material through a roll coater or the like in this laminated state, the thickness is adjusted while foaming the raw material. It is not required whether or not a release sheet supplied from above is used, but using this release sheet makes it easy to adjust the thickness of the foam before hardening, and a skin layer can be formed on the surface of the foam obtained after heat treatment. Furthermore, when using a material that is foamed before application (for example, an emulsion composition) as a raw material, the raw material is applied to the release paper using known means such as a doctor knife or doctor roll to adjust it to the desired thickness. These processes make it possible to obtain a laminate in which a release sheet is laminated on at least one side of the foam layer before curing. Subsequently, this laminate is heated using a heat treatment device. This allows it to harden and dry, forming a foam layer.

[0341] Furthermore, when using a crosslinked polyolefin resin foam as the foam, a polyolefin resin and a pyrolysis-type foaming agent are supplied to an extruder and melt-kneaded to obtain raw materials, which are then extruded from the extruder into a sheet to form a foamable polyolefin resin sheet. The sheet is then irradiated with an electron beam to crosslink the resin, and the foam is subsequently foamed, stretched, and thinned to obtain the foam. Conventional polyolefin resins can be used, but those containing 40% by mass or more of polyethylene resin obtained using a metallocene compound containing a tetravalent transition metal are preferred. Alternatively, after foaming the foam, the foamed sheet may be sliced ​​in the thickness direction, stretched with a hot roll, and then coated to produce the foam.

[0342] The lamination process involves laminating a first base material layer, each adhesive layer, and a foam layer. There are no particular restrictions on the method of laminating the first base material layer, each adhesive layer, and the foam layer; an appropriate method can be selected from known methods. For example, a method can be used in which the adhesive layer, the first base material layer, and the foam layer, which are attached to the release sheet formed in the adhesive layer formation process, are laminated under pressure. Specifically, the first adhesive layer is laminated to the first base material layer, and the third adhesive layer is laminated to the foam layer. Then, the laminate on the first base material layer side and the laminate on the foam layer side are laminated with the foam layer in between, thereby obtaining the adhesive tape of the first embodiment.

[0343] 《Adhesive tape of the second embodiment》 The adhesive tape of the second embodiment according to this embodiment comprises, in order, a first adhesive layer, a first base material layer, a second adhesive layer, a foam layer, and a third adhesive layer, wherein the breaking strength of the first base material layer is 1.0 to 100.0 MPa, the breaking elongation of the first base material layer is 400 to 1500%, the 25% compressive strength of the foam in the foam layer is 40 to 160 kPa, and the tensile strength of the foam layer is 3.0 to 15.0 MPa. The adhesive tape of the second embodiment is defined as having a second adhesive layer between the first base material layer and the foam layer, compared to the adhesive tape of the first embodiment described above. In this embodiment, the second adhesive layer is a layer that enables the adhesive tape to be joined together with the portion on the first base material layer side and the portion on the foam layer side. When peeling off the adhesive tape of the second embodiment, it is preferable that the second adhesive layer stretches in accordance with the first substrate layer. This reduces the amount of residue left on the adherend by the second adhesive layer.

[0344] The following describes the different constituent elements of the adhesive tape of the second embodiment compared to the adhesive tape of the first embodiment described above, while the same constituent elements will not be explained. Furthermore, in the third embodiment, similar to the first and second embodiments, it is preferable that the adhesive layer adjacent to the first base layer, specifically the first adhesive layer, and preferably the first and second adhesive layers, contain a predetermined amount of filler particles as described above. In the third embodiment, by containing filler particles in the adhesive layer adjacent to the first base layer, particularly the first adhesive layer, the adhesive tape can be peeled off more easily, thus facilitating the peeling process. In addition, by also containing filler particles in the second adhesive layer, the adhesive force can be reduced when peeling the adhesive tape from between the first and second adherends, even when peeling it from between the fourth adhesive layer (described later), making it even easier to peel off the adhesive tape.

[0345] The adhesive composition forming the second adhesive layer may contain an adhesive resin similar to that described in the first embodiment above, and, as in the first embodiment above, may also contain filler particles and other components as needed in addition to the adhesive resin. Furthermore, the second adhesive layer may have the same adhesive composition as the first or third adhesive layer, or a different adhesive composition. In addition, the second adhesive layer may have the same range of properties and thickness as the first or third adhesive layer.

[0346] Furthermore, in the second embodiment, similar to the first embodiment, it is preferable that the adhesive layer adjacent to the first base layer, specifically the first adhesive layer, and preferably the first and second adhesive layers, contain a predetermined amount of filler particles as described above. In the second embodiment, by containing filler particles in the adhesive layer adjacent to the first base layer, particularly the first adhesive layer, the adhesive tape can be peeled off more easily, thus facilitating the peeling process. In addition, by also containing filler particles in the second adhesive layer, the adhesive force can be easily reduced when peeling the adhesive tape from between the first and second adherends, making it even easier to peel off the adhesive tape.

[0347] <Shape, characteristics, etc. of adhesive tape> The adhesive tape of the second embodiment may have the same shape, properties, and thickness as the adhesive tape of the first embodiment.

[0348] <Method for manufacturing adhesive tape> In the second embodiment, the method for manufacturing the adhesive tape is not particularly limited and can be appropriately selected from known methods. Specifically, in the adhesive tape of the second embodiment, the first base layer, each adhesive layer, and the foam layer can be obtained in the same manner as the adhesive layer formation step, the first base layer formation step, and the foam layer formation step in the manufacturing method of the adhesive tape of the first embodiment. Furthermore, in the adhesive tape of the second embodiment, the adhesive tape can be obtained by pressurizing and laminating the adhesive layer, the first base layer, and the foam layer while they are attached to the release sheet. Specifically, the first adhesive layer and the second adhesive layer, while attached to the release sheet, are laminated to both sides of the first base layer, and the third adhesive layer, while attached to the release sheet, is laminated to the surface of the foam layer. Subsequently, the adhesive tape of the second embodiment can be obtained by laminating the laminate on the first base layer side and the laminate on the foam layer side so that they face each other.

[0349] 《Adhesive tape of the third embodiment》 The adhesive tape of the third embodiment according to this embodiment comprises, in order, a first adhesive layer, a first base material layer, a second adhesive layer, a fourth adhesive layer, a foam layer, and a third adhesive layer, wherein the breaking strength of the first base material layer is 1.0 to 100.0 MPa, the breaking elongation of the first base material layer is 400 to 1500%, the 25% compressive strength of the foam in the foam layer is 40 to 160 kPa, and the tensile strength of the foam layer is 3.0 to 15.0 MPa. The adhesive tape of the third embodiment is characterized by having a fourth adhesive layer between the second adhesive layer and the foam layer, compared to the adhesive tape of the second embodiment described above. Therefore, the adhesive tape of the third embodiment makes it easier to peel the adhesive tape from between the first adherend and the second adherend compared to the adhesive tape of the second embodiment. Specifically, when peeling off the adhesive tape of the second embodiment, the second adhesive layer stretches to follow the first substrate layer, and at that time, there is a risk that the second adhesive layer will peel off while tearing the foam layer, which remains on the adherend. Therefore, in the adhesive tape of the second embodiment, if the second adhesive layer peels off while tearing the foam layer, the residue, including the torn foam layer, must be peeled off the adherend after the first adherend and the second adherend have been separated. In contrast, in the adhesive tape of the third embodiment, the adhesive strength between adjacent adhesive layers (between the second adhesive layer and the fourth adhesive layer) tends to be lower than the adhesive strength between the adhesive layer and the first substrate or between the adhesive layer and the foam layer (because the anchoring effect is not easily exerted between the adhesive layers). Therefore, in the adhesive tape of the third embodiment, the presence of the fourth adhesive layer reduces the tearing of the foam layer by the second adhesive layer, which peels off together with the first substrate layer. Consequently, in the adhesive tape of the third embodiment, the foam layer as residue is less likely to tear, so the residue can be easily removed, making the peeling process easier.

[0350] The following describes the different constituent elements of the adhesive tape of the third embodiment compared to the adhesive tape of the first embodiment described above, while the same constituent elements will not be explained. <Adhesive layer> The adhesive tape of the third embodiment, compared to the adhesive tape of the first embodiment, includes a second adhesive layer and a fourth adhesive layer between the foam layer and the first base layer. More specifically, in the adhesive tape of the third embodiment, the second adhesive layer is positioned on the first base layer side and the fourth adhesive layer is positioned on the foam layer side between the first base layer and the foam layer. Furthermore, compared to the adhesive tape of the second embodiment (particularly the adhesive layer), the configuration of the adhesive layer of the third embodiment includes a fourth adhesive layer between the second adhesive layer and the foam layer. The fourth adhesive layer, together with the second adhesive layer, is a layer that enables the bonding of the portion of the adhesive tape on the first base layer side and the portion on the foam layer side. The adhesive composition forming the fourth adhesive layer may contain an adhesive resin similar to that described in the first embodiment, and, as in the first embodiment, may also contain filler particles and other components as needed. Furthermore, the fourth adhesive layer may have the same adhesive composition as the first, second, and third adhesive layers, or a different adhesive composition. In addition, the fourth adhesive layer may have the same range of properties and thickness as the first, second, and third adhesive layers.

[0351] Furthermore, in the third embodiment, similar to the first or second embodiment, it is preferable that the adhesive layer adjacent to the first base layer, specifically the first adhesive layer, preferably the first and second adhesive layers, contain a predetermined amount of filler particles as described above. In the third embodiment, by including filler particles in the adhesive layer adjacent to the first base layer, particularly the first adhesive layer, the adhesive tape can be peeled off more easily, thus facilitating the peeling process. In addition, by including filler particles in the second adhesive layer, the adhesive force can be reduced when peeling the adhesive tape from between the first and second adherends, even between the fourth adhesive layer and the second adherend, making it even easier to peel off the adhesive tape.

[0352] <Shape, characteristics, etc. of adhesive tape> The adhesive tape of the third embodiment may have the same shape, properties, and thickness as the adhesive tape of the first or second embodiment.

[0353] <Method for manufacturing adhesive tape> In the third embodiment, the method for manufacturing the adhesive tape is not particularly limited and can be appropriately selected from known methods. Specifically, in the adhesive tape of the third embodiment, the first base layer, each adhesive layer, and the foam layer can be obtained in the same manner as the adhesive layer formation step, the first base layer formation step, and the foam layer formation step in the manufacturing method of the adhesive tape of the first embodiment. Furthermore, in the adhesive tape of the third embodiment, the adhesive tape can be obtained by pressurizing and laminating the adhesive layer, the first base layer, and the foam layer while they are attached to the release sheet. Specifically, the first and second adhesive layers, while attached to the release sheet, are laminated to both sides of the first base layer, and the third and fourth adhesive layers, while attached to the release sheet, are laminated to both sides of the foam layer. Subsequently, the laminate on the first base layer side and the laminate on the foam layer side are laminated so that the second and fourth adhesive layers face each other, thereby obtaining the adhesive tape of the third embodiment.

[0354] 《Adhesive tape of the fourth embodiment》 The adhesive tape of the fourth embodiment of this disclosure comprises, in order, a first adhesive layer, a first base layer, a second adhesive layer, a second base layer, a fourth adhesive layer, a foam layer, and a third adhesive layer, wherein the first base layer has a breaking strength of 1.0 to 100.0 MPa and a breaking elongation of 400 to 1500%, and the foam layer has a 25% compressive strength of 40 to 160 kPa and a tensile strength of 3.0 to 15.0 MPa. The adhesive tape of the fourth embodiment is defined as having a second base material layer between the second adhesive layer and the fourth adhesive layer, compared to the adhesive tape of the third embodiment described above. Therefore, the adhesive tape of the third embodiment can be manufactured more easily than the adhesive tape of the second embodiment. Specifically, as described above, the adhesive tape of the third embodiment can be obtained by laminating the laminate on the first base material layer side and the laminate on the foam layer side so that the second adhesive layer and the fourth adhesive layer face each other. In contrast, the adhesive tape of the fourth embodiment can be obtained by first attaching the second base material layer to the surface of the adhesive layer of one of the laminates, and then attaching the other laminate to the surface of the second base material layer, before laminating the laminate on the first base material layer side and the laminate on the foam layer side. In other words, in the adhesive tape of the fourth embodiment, the process of attaching the second adhesive layer and the fourth adhesive layer is not performed with the adhesive layer surfaces of the second and fourth adhesive layers exposed, so the lamination of the laminate on the first base material layer side and the laminate on the foam layer side can be performed more easily. Furthermore, according to the adhesive tape of the fourth embodiment, when separating the first and second adherends bonded together with the adhesive tape, if the first base material layer is pulled out from between each adherend together with the first and second adhesive layers, the interface between the second adhesive layer and the second base material layer peels off, which suppresses the stress caused by the conformation of the foam layer, making it easy to pull out. Also, after separation, there may be residue of the adhesive tape with the second base material layer on its surface between each adherend. In that case, since the second base material layer on the surface of the residue is non-adhesive, re-adhesion between each adherend can be avoided, making it easier to separate the joined body.

[0355] The following describes the constituent elements of the adhesive tape of the fourth embodiment, which differ from those of the adhesive tapes of the first, second, and third embodiments described above, while the same constituent elements will not be described. <Second base layer> The adhesive tape of the fourth embodiment is defined as having a second base material layer between the second adhesive layer and the fourth adhesive layer, compared to the adhesive tape of the third embodiment. The material of the second base layer is not particularly limited, but examples include resin sheets, nonwoven fabrics, paper, metal foil, woven fabric, rubber sheets, foamed sheets, and laminates thereof (especially laminates including resin sheets). Examples of resins constituting the resin sheet include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), fully aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluororesins, and polyether ether ketone (PEEK). Examples of nonwoven fabrics include nonwoven fabrics of natural fibers (cellulose fibers); and nonwoven fabrics of synthetic resin fibers such as polypropylene resin fibers, polyethylene resin fibers, and polyester resin fibers. Examples of metal foils include copper foil, stainless steel foil, and aluminum foil. Examples of paper include Japanese paper and kraft paper. As the second base material layer, a resin sheet is preferred among the above, and more preferably a resin sheet made of polyethylene terephthalate, from the viewpoint of ease of handling.

[0356] The thickness of the second substrate layer is not particularly limited, but is preferably 2 to 200 μm, more preferably 5 to 100 μm, even more preferably 10 to 50 μm, and even more preferably 10 to 30 μm.

[0357] Furthermore, the elongation at break of the second base material layer is 500% or less, preferably 400% or less, and more preferably 300% or less. Having an elongation at break of 500% or less facilitates the disassembly of adherends joined using adhesive tape.

[0358] <Shape, characteristics, etc. of adhesive tape> The adhesive tape of the fourth embodiment may have the same shape, properties, and thickness as the adhesive tape of the first, second, or third embodiment.

[0359] <Method for manufacturing adhesive tape> In the fourth embodiment, the method for manufacturing the adhesive tape is not particularly limited and can be appropriately selected from known methods. Specifically, in the adhesive tape of the fourth embodiment, the first base layer, each adhesive layer, and the foam layer can be obtained in the same manner as the adhesive layer formation step, the first base layer formation step, and the foam layer formation step in the manufacturing method of the adhesive tape of the first embodiment. Furthermore, in the adhesive tape of the fourth embodiment, the adhesive tape can be obtained by pressurizing and laminating the adhesive layer, the first base layer, the second base layer, and the foam layer while they are attached to the release sheet. Specifically, the first and second adhesive layers, while attached to the release sheet, are laminated to both sides of the first base layer, and the third and fourth adhesive layers, while attached to the release sheet, are laminated to both sides of the foam layer. Subsequently, the second base layer is bonded to the surface of the second adhesive layer on the laminate on the first base layer side, or to the surface of the fourth adhesive layer on the laminate on the foam layer side. Next, the adhesive tape of the fourth embodiment can be obtained by laminating a laminate without the second base layer onto the surface of a laminate with the second base layer attached, such that the second adhesive layer and the fourth adhesive layer face each other with the second base layer in between.

[0360] Uses of adhesive tape The adhesive tape of this embodiment can be suitably used for fixing parts in various industrial fields, such as fixing sheet metal parts together or fixing exterior parts to housings in relatively large electronic devices such as flat-screen TVs, home appliances, and office automation equipment, as well as fixing rigid parts such as exterior parts and batteries to relatively small electronic devices such as portable electronic terminals, cameras, and personal computers, and for applications such as labels that display product information.

[0361] [zygote] The bonding body of this embodiment comprises the adhesive tape of the above-described embodiment of the present invention, a first adherend that adheres to the surface of the first adhesive layer of the adhesive tape, and a second adherend that adheres to the surface of the third adhesive layer of the adhesive tape. According to the bonding body of this embodiment, the adhesive tape can be easily peeled off, and sufficient adhesion between adherends in the bonding body can be maintained. Here, the bonding body of this embodiment more specifically includes the adhesive tape of the first embodiment (bonding body of the first embodiment) described above, or a bonding body using the adhesive tape of the second embodiment or the adhesive tape of the third embodiment (bonding body of the second embodiment), and a bonding body using the adhesive tape of the fourth embodiment described above (bonding body of the third embodiment).

[0362] <First adherend, second adherend> The first and second adherends are not particularly limited and can be components of products used in various industrial fields such as office automation equipment, IT and home appliances, and automobiles. An example of a combination of the first and second adherends is to use one adherend as the housing of the product and the other adherend as a component such as a battery, electronic component, structural component, or display element incorporated into the product. The first and second adherends can then be fixed or temporarily fixed with adhesive tape. Alternatively, an example of a combination of the first and second adherends is to use one adherend as a display unit for displaying a label showing product information, and the other adherend as the label itself. Furthermore, the materials forming the surfaces of the first and second adherends can be arbitrarily chosen depending on the first and second adherends, but they can be, for example, made of resin or metal.

[0363] The first adhesive surface of the first adherend to which the adhesive tape is attached, and the second adhesive surface of the second adherend to which the adhesive tape is attached, can be smooth flat surfaces, but the adhesive surfaces may also be curved.

[0364] [Method for disassembling the joint] The method for dismantling the joint of this embodiment is a method for dismantling the joint of the embodiment of the present invention described above, and includes a step of separating the second adherend from the first adherend. According to the method for dismantling the joint of this embodiment, the joint can be easily dismantled. Here, the method for dismantling the joint of this embodiment more specifically includes a method for dismantling the joint of the first embodiment (method for dismantling the joint of the first embodiment), a method for dismantling the joint of the second embodiment (method for dismantling the joint of the second embodiment), and a method for dismantling the joint of the third embodiment (method for dismantling the joint of the third embodiment).

[0365] Method for disassembling the joint of the first embodiment The method for disassembling the joint according to the first embodiment is the method for disassembling the joint according to the first embodiment, and comprises the step of stretching at least the first base material layer of the adhesive tape to separate the second adherend from the first adherend. The adhesive tape used in the first embodiment comprises, in order, a first adhesive layer, a first base material layer, a foam layer, and a third adhesive layer. In the method for disassembling the joint of the first embodiment, in order to separate (disassemble) the second adherend from the first adherend, specifically, at least the first base material layer of the adhesive tape is stretched, thereby peeling (removing) at least the first adhesive layer (preferably the first adhesive layer) together with the first base material layer from between the first adherend and the second adherend. This makes it possible to separate (disassemble) the second adherend from the first adherend. At this time, since the foam layer is not as stretchable as the first base material layer, the foam layer and the third adhesive layer may remain attached to the adherend and become residue. In this case, for example, the residue can be removed after separating (disassembling) the second adherend from the first adherend.

[0366] In the first embodiment, in order to separate (disassemble) the second adherend from the first adherend, layers other than the first base material layer of the adhesive tape, such as the foam layer, may also be stretched. However, if the first base material layer is stretched, the foam layer will not stretch as easily, and there is a risk that the foam layer may tear along the way.

[0367] Method for disassembling the joint in the second embodiment The method for disassembling the joint of the second embodiment is the method for disassembling the joint of the second embodiment described above, and comprises the step of stretching at least the first base material layer of the adhesive tape to separate the second adherend from the first adherend. The adhesive tape used in the second or third embodiment comprises a first adhesive layer, a first base material layer, a second adhesive layer, a foam layer, and a third adhesive layer in that order, and optionally further comprises a fourth adhesive layer between the second adhesive layer and the foam layer. In the method for disassembling the joint of the second embodiment, in order to separate (disassemble) the second adherend from the first adherend, specifically, at least the first base material layer of the adhesive tape is stretched, thereby peeling (removing) at least the first adhesive layer (preferably the first and second adhesive layers) together with the first base material layer from between the first and second adherends. This makes it possible to separate (disassemble) the second adherend from the first adherend. At this time, since the foam layer is not as stretchable as the first base material layer, the foam layer and the third adhesive layer may remain attached to the adherend and become residue. In this case, for example, the residue can be removed after separating (disassembling) the second adherend from the first adherend.

[0368] In the second embodiment, in order to separate (disassemble) the second adherend from the first adherend, layers other than the first base layer of the adhesive tape, such as the foam layer, may also be stretched. However, if the first base layer is stretched, the foam layer will not stretch as easily, and there is a risk that the foam layer may tear along the way. Furthermore, because the adhesive tape has a second adhesive layer, the adhesive strength between the second adhesive layer and the foam layer is relatively lower than the adhesive strength between the first base material layer and the second adhesive layer. Therefore, when the first base material layer is stretched, the second adhesive layer tends to peel off along with the first base material layer. Furthermore, if the adhesive tape includes a fourth adhesive layer, the adhesive strength between the second adhesive layer and the fourth adhesive layer is relatively lower than the adhesive strength between the first substrate layer and the second adhesive layer, and the adhesive strength between the fourth adhesive layer and the foam layer. Therefore, when the first substrate layer is stretched, the second adhesive layer also peels off following the first substrate layer, while the fourth adhesive layer tends to remain attached to the substrate along with the foam layer.

[0369] Method for disassembling the joint in the third embodiment The method for disassembling the joint of the third embodiment is a method for disassembling the joint of the third embodiment described above, comprising the step of separating the second adherend from the first adherend by stretching at least the first base layer of the adhesive tape while leaving the second base layer of the adhesive tape on the surface of the second adherend. The adhesive tape used in the third embodiment comprises, in order, a first adhesive layer, a first base layer, a second adhesive layer, a second base layer, a fourth adhesive layer, a foam layer, and a third adhesive layer. In the third embodiment, the method for dismantling the jointed body involves separating (dismantling) the second adherend from the first adherend by stretching at least the first base material layer of the adhesive tape while leaving the second base material layer on the surface of the second adherend, thereby peeling (removing) at least the first adhesive layer (preferably the first and second adhesive layers) together with the first base material layer from between the first and second adherends. In the second embodiment, a method for leaving the second base material layer on the surface of the second adherend is to avoid removing the second base material layer when stretching the first base material layer and removing it from between the first and second adherends, or more specifically, not pulling the second base material layer together with the first base material layer, or not continuing to pull it together. In the method for dismantling the joint of the third embodiment, when at least the first adhesive layer is peeled away from the first adherend and the second adherend, the second base material layer, the fourth adhesive layer, the foam layer, and the third adhesive layer remain attached to the adherend and become residue. Therefore, after separating (dismantling) the second adherend from the first adherend, the residue is removed.

[0370] In the third embodiment, when the first base layer is peeled off together with the first and second adhesive layers, there will be residue of adhesive tape having the second base layer on its surface between the first and second adherends. However, since the second base layer is non-adhesive, re-adhesion between the first and second adherends can be avoided, making disassembly easier. Furthermore, in the third embodiment, if, for example, a second base material is used in the adhesive tape, when stretching at least the first base material layer of the adhesive tape, the second base material layer, etc. (for example, all layers of the adhesive tape) may also be stretched together with the first base material layer. In this case, the second base material layer, etc. (for example, the portion of the adhesive tape including the second base material layer, the fourth adhesive layer, the foam layer, and the third adhesive layer) will tear during the stretching process, so the first base material layer can be peeled off together with the first and second adhesive layers while leaving residue including the second base material layer, etc. on the surface of the second adherend.

[0371] Although embodiments of the present invention have been described above, the adhesive tape of the present invention is not limited to the above examples and can be modified as appropriate. [Examples]

[0372] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0373] The measurement and evaluation of the adhesive tapes obtained in each example and comparative example were performed based on the following method.

[0374] (1) Measurement of the breaking strength and elongation of the base material layer Each base material layer was punched out in a dumbbell shape with a gauge length of 20 mm and a width of 5 mm. The breaking strength and elongation at break of the base material layer were measured by pulling it 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. The results are shown in Table 1 below.

[0375] (2) Measurement of the thickness of the base layer, adhesive layer, and foam layer The thickness of five arbitrary points within the base layer, adhesive layer, and foam layer was measured using a TH-104 paper and film thickness measuring instrument (manufactured by Tester Sangyo Co., Ltd.). The average of these measurements was used as the thickness of the base layer and adhesive layer.

[0376] (3) Measurement of 25% compressive strength Foam cut into 50mm squares was stacked until it reached a thickness of approximately 10mm, and then sandwiched between plates with a larger surface area. The foam was compressed by approximately 2.5mm (25% of its original thickness) at a speed of 10mm / min at 23°C, then stopped, and the strength was measured after 20 seconds. This strength was defined as the 25% compressive strength. The strength was measured using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.).

[0377] (4) Measurement of the tensile strength of the foam layer Test specimens of the foam layer were cut to a length of 2 cm and a width of 1 cm. These specimens were measured using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of 23°C and 50% RH, at a tensile speed of 300 mm / min. The maximum strength among the obtained measurements was defined as the tensile strength.

[0378] (5) Evaluation of stretchable peelability Each piece of adhesive tape was cut to a length of 60 mm and a width of 10 mm. Of these, with 10 mm in length and 10 mm in width protruding to serve as a gripping hand, one side of the adhesive tape (the third adhesive layer side) was attached to a clean, smooth aluminum plate (150 mm in length, 50 mm in width, 2 mm in thickness, alloy number A1050) under conditions of 23°C and 50% RH. Next, a clean, smooth acrylic plate (150 mm in length, 50 mm in width, 2 mm in thickness, Acrylite L, color: colorless, manufactured by Mitsubishi Rayon Co., Ltd.) was attached to the side of the adhesive tape opposite to the side to which the aluminum plate was attached (the first adhesive layer side). A load of 5 kg was applied to the laminated structure of the aluminum plate, the adhesive tape, and the acrylic plate, and the material was pressed down by rolling it back and forth once while applying pressure. After that, the material was left to stand for 3 days under conditions of 23°C and 50% RH to obtain the test specimen. Under conditions of an atmosphere of 23°C and 50% RH, the gripping portion of the adhesive tape (first adhesive layer, first base layer, and second adhesive layer) of the test specimen was stretched horizontally with respect to the application surface of the adhesive tape using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) at a tensile speed of 300 mm / min. The above method was used to perform the test 10 times, and the re-peelability (stretch peelability) was evaluated based on the evaluation criteria below. The results are shown in Tables 1-3 below. [Evaluation Criteria] ◎: The number of times the material could be pulled out from between the acrylic plate and the aluminum plate without cutting at least the first base layer was 9 or more out of 10 attempts. ○: The number of times the material could be pulled out from between the acrylic plate and the aluminum plate without cutting at least the first base layer was 5 to 9 times out of 10 attempts. ×: The number of times the material could be pulled out from between the acrylic and aluminum plates without cutting at least the first base layer was 4 to 1 out of 10 attempts. ×: The number of times the material could be pulled out from between the acrylic plate and the aluminum plate without cutting at least the first base layer was 0 out of 10 attempts. ◎ and ○ indicate items that are perfectly usable.

[0379] (6) Method for evaluating conformability in the thickness direction The adhesive tapes obtained in the examples and comparative examples were cut into frame shapes with outer dimensions of 50 mm x 40 mm and a width of 1 mm. The first adhesive layer of the cut adhesive tape was attached to a stainless steel plate 1 (thickness 2 mm, outer dimensions 65 mm x 45 mm) with a 10 mm diameter hole in the center. Next, the third adhesive layer of the above adhesive tape is bonded to the stainless steel plate 2 (2 mm thick, outer dimensions 65 mm x 45 mm) at 23°C, with an adhesive strength of 50 N / cm². 2 The bonded body was obtained by applying pressure with a load for 5 seconds and then leaving it in a 23°C environment for 24 hours. Next, to evaluate the conformability of the adhesive tape in the thickness direction, conformability evaluation samples were prepared using spacers with thicknesses in 0.05 mm increments, such that the distance between stainless steel plate 1 and stainless steel plate 2 of the joint obtained above was +0.00 mm, +0.05 mm, +0.10 mm, +0.15 mm, +0.20 mm, ..., +0.50 mm relative to the thickness of the adhesive tape. After leaving the conformability evaluation samples in a 23°C, 50% RH environment for 48 hours, an internal air pressure of 15 kPa was applied for 5 seconds through a hole in the center of stainless steel plate 1 to evaluate whether or not there was air leakage. ◎: Even when a gap 1.30 times the thickness of the adhesive tape is provided No air leaks were detected at all. ○: Even when a gap 1.25 times the thickness of the adhesive tape is provided No air leaks were detected at all. △: Even when a gap 1.20 times the thickness of the adhesive tape is provided No air leaks were detected at all. ×: Air leakage was observed when a gap 1.20 times the thickness of the adhesive tape was provided.

[0380] (7) Measurement of frictional force The frictional force of the adhesive layer of the adhesive tape (at 23°C) was measured in accordance with the measuring device defined in JIS K7125. A stainless steel plate (40cm) with felt on one side was used as the sliding surface. 2 A felt surface and cotton canvas #9 were prepared by bonding them together with double-sided tape (DIC #8800CH) via a 200g load. The cotton canvas #9 referred to here is No. 9 cotton canvas (based on the old JIS L3102), with yarn twist (warp 10 / 2, weft 10 / 3), density (warp 44-48 threads / inch, weft 33-37 threads / inch), and weight 510g / m². 2 )] refers to the following. Next, the adhesive tape to be used for evaluation was cut to a size of 100 mm wide x 200 mm long and fixed to a smooth, horizontal test table so that the adhesive layer surface of the tape to be measured was facing upwards. The stress value was measured when the sliding piece slid on the adhesive layer surface of the tape to be measured. Note that the stress value obtained by this measurement method is a continuous measurement of static friction force because the frictional force against the adhesive layer surface is high. For this reason, a graph of the stress value and the distance the sliding piece moved was created, and the stress value for a distance of 50 mm was extracted from the distance range in which the stress value was relatively stable, and the arithmetic mean of the peak values ​​of the extracted stress values ​​was taken as the friction force.

[0381] (8) Measurement of average particle size and number average primary particle size (Measurement of average particle size) The average particle size of filler particles used in adhesive compositions was measured using a laser diffraction scattering measuring instrument (Microtrac). (Measurement of number-mean primary particle size) Adhesive tape cooled under liquid nitrogen was randomly cut in three places using a microtome, and three fragments were used as samples. A scanning electron microscope (STEM) was used to take 400x magnification images of each sample. From the three resulting images, solid particles were separated from the fillers. Then, using image analysis software, the cross-sectional area of ​​the solid particles was calculated (e.g., Otsu's binarization process) and treated as the area of ​​a circle. The equivalent diameter of each solid particle was then measured. The total number of solid particles in the three images and their corresponding equivalent diameters were calculated, and the number-average primary mean particle diameter of the filler particles was calculated using the following equation (A).

number

[0382] Next, the materials used in the examples and comparative examples are as follows. <Material for base material> ·Base material (1) (SIS) As the base material (1), SIS resin (Quintac 3620, manufactured by Nippon Zeon Co., Ltd.) was used. ·Base material (2) (SEEPS) In a nitrogen-purged and dried pressure vessel, 3,000 mL of cyclohexane was charged as the solvent, and 9.2 mL of sec-butyllithium (cyclohexane solution) at a concentration of 10.5% by mass was charged as an initiator. After raising the temperature to 60°C, 100 mL of styrene was added and polymerization was carried out for 60 minutes. Subsequently, 270 mL of isoprene and 350 mL of butadiene were added at the same temperature, and the mixture was reacted for 90 minutes. Then, 100 mL of styrene was added at the same temperature, and polymerization was carried out for 60 minutes. After that, polymerization was stopped with 0.52 mL of methanol to obtain a polymerization reaction solution containing the block copolymer. To this reaction mixture, 29.3 g of palladium carbon (palladium loading: 5% by mass) was added as a hydrogenation catalyst, and the hydrogenation reaction was carried out at a hydrogen pressure of 2 MPa and 150°C for 10 hours. After cooling and release of pressure, the palladium carbon was removed by filtration, the filtrate was concentrated, and further vacuum-dried to obtain the base material (2). The obtained base material (2) had a styrene content of 30% by mass, a weight-average molecular weight of 98,000, a molecular weight distribution of 1.03, and a hydrogenation rate of 98%.

[0383] • Base material (3) (urethane) As the base material (3), an ester-based polyurethane sheet (manufactured by Nisshinbo Textiles Inc., Mobilon Film MF50T, 50 μm thick) was used.

[0384] ·Base material (4) (PET) As the base material (4), a PET film (Toray Industries, Inc., Lumirror S10, 12 μm thick) was used.

[0385] ·Base material (5) (PET) As the base material (5), a PET film (Toray Industries, Inc., Lumirror S10, 50 μm thick) was used.

[0386] <Filler particles> • Filler particles (1) (silicone-based filler) As filler particles (1), silicone composite particles (KMP-601 manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 12 μm) were used.

[0387] • Filler particles (2) (silicone-based filler) As filler particles (2), silicone composite particles (KMP-602 manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 30 μm) were used.

[0388] <Adhesive resin> • Method for preparing adhesive resin (1) (acrylic) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, 75.94 parts by mass of n-butyl acrylate, 5 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of cyclohexyl acrylate, 4 parts by mass of acrylic acid, 0.06 parts by mass of 4-hydroxybutyl acrylate, and 200 parts by mass of ethyl acetate were charged, and the mixture was heated to 65°C while stirring and blowing in nitrogen to obtain mixture (1). Next, 4 parts by mass of 2,2'-azobisisobutyronitrile solution (2.5% by mass of solids) that had been previously dissolved in ethyl acetate was added to mixture (1), and the mixture was held at 65°C for 10 hours while stirring to obtain mixture (2). Next, mixture (2) was diluted with 98 parts by mass of ethyl acetate and filtered through a 200-mesh wire mesh to obtain an acrylic copolymer solution (1) with a weight-average molecular weight of 1.6 million (polystyrene equivalent). Next, 100 parts by mass of the acrylic copolymer solution (1) was mixed and stirred with 5 parts by mass of polymerized rosin ester tackifying resin (D-125, Arakawa Chemical Industries, Ltd.) and 15 parts by mass of petroleum-based tackifying resin (FTR® 6125, manufactured by Mitsui Chemicals, Inc.), and then ethyl acetate was added to obtain an adhesive resin solution (1) containing an adhesive resin (1) with a solid content of 35% by mass.

[0389] • Method for preparing adhesive resin (2) (acrylic) A mixed solution was prepared 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 to a 1000 ml flask whose interior was purged with argon. To this mixed solution, 12.0 ml of methyl methacrylate (MMA) was added at 0°C and the mixture was stirred at 0°C for 30 minutes. Then, 20 ml of the solution was sampled from the system (Sample 1). After the polymerization of 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, and the mixture was stirred at -78°C for 3 hours. Then, 20 ml of the solution was sampled from the system (Sample 2). After the polymerization of nBA, 12.0 ml of MMA was added to this polymerization system as the third monomer at -78°C and the solution was stirred. After the solution became homogenized, the temperature was raised to 0°C and the mixture was stirred for another hour. Polymerization was stopped by adding 50 ml of methanol to the resulting reaction mixture and allowing it to react at room temperature for 2 hours. The reaction solution after polymerization cessation was poured into a large amount of hexane to obtain a precipitated white precipitate. A portion of the white precipitate was then sampled (Sample 3).

[0390] NMR, DSC, and GPC (gel permeation chromatography) measurements were performed on each polymer in samples 1 to 3 above. Based on these measurement results, the number-average molecular weight (Mn), PMMA / PnBA (polymethyl methacrylate block / polyacrylate n-butyl block) ratio, etc., were determined, and it was confirmed that the above white precipitate is a triblock copolymer of polymethyl methacrylate (PMMA) block - polyacrylate n-butyl (PnBA) block - polymethyl methacrylate (PMMA) block (PMMA-b-PnBA-b-PMMA, hereinafter referred to as triblock copolymer (1)). Furthermore, it was confirmed that the syndiotacticity of the PMMA block portion of the triblock copolymer (1) was 71%, the glass transition temperature of the PMMA block portion was 113.7°C, the glass transition temperature of the PnBA block portion was -46.8°C, the total Mn content of the copolymer was 95936, the total Mw / Mn (molecular weight distribution) of the copolymer was 1.09, and the proportion of each polymer block was PMMA (11 wt%) - PnBA (78 wt%) - PMMA (11 wt%). The white precipitate obtained above was diluted with ethyl acetate to obtain an adhesive resin solution (2) containing an adhesive resin (2) with a solid content of 45% by mass.

[0391] <Adhesive composition> • Adhesive composition (1) To 100 parts by mass of the solid content of the adhesive resin solution (1) obtained above, 30 parts by mass of filler particles (1) were added. Subsequently, 1.3 parts by mass of a crosslinking agent (Barnock D-40, manufactured by DIC Corporation; trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by mass, nonvolatile content 40% by mass) was added to the solution containing the filler particles (1) based on 100 parts by mass of the adhesive resin solution (1). After stirring and mixing until homogeneous, ethyl acetate was added to obtain an adhesive composition (1) with a solid content of 40% by mass.

[0392] • Adhesive composition (2) To 100 parts by mass of the solid content of the adhesive resin solution (2) obtained above, 30 parts by mass of filler particles (1) were added, and after stirring and mixing until homogeneous, ethyl acetate was added to obtain an adhesive composition (2) with a solid content of 45% by mass.

[0393] • Adhesive composition (3) To 100 parts by mass of the solid content of the adhesive resin solution (1) obtained above, 30 parts by mass of filler particles (2) were added. Subsequently, 1.3 parts by mass of a crosslinking agent (Barnock D-40, manufactured by DIC Corporation; trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by mass, non-volatile content 40% by mass) was added to the solution containing the filler particles (2) based on 100 parts by mass of the adhesive resin solution (1). After stirring and mixing until homogeneous, ethyl acetate was added to obtain an adhesive composition (3) with a solid content of 40% by mass.

[0394] • Adhesive composition (4) To 100 parts by mass of the solid content of the adhesive resin solution (1) obtained above, 1.3 parts by mass of a crosslinking agent (Barnock D-40, manufactured by DIC Corporation; trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by mass, nonvolatile content 40% by mass) and ethyl acetate were added to obtain an adhesive composition (4) with a solid content of 40% by mass.

[0395] <Foam> • Foam (1) (PE foam) A black polyolefin foam (thickness: 150 μm, foaming ratio: 3x, 25% compressive strength: 70 kPa, tensile strength: 10 MPa) was prepared.

[0396] • Foam (2) (PE foam) A black polyolefin foam (thickness: 150 μm, foaming ratio: 2.2 times, 25% compressive strength: 150 kPa, tensile strength: 14 MPa) was prepared.

[0397] • Foam (3) (PE foam) A black polyolefin foam (thickness: 150 μm, foaming ratio: 5x, 25% compressive strength: 190 kPa, tensile strength: 5 MPa) was prepared.

[0398] • Foam (4) (PE foam) A black polyolefin foam (thickness: 100 μm, foaming ratio: 1.9 times, 25% compressive strength: 50 kPa, tensile strength: 16 MPa) was prepared.

[0399] Next, we will describe the examples and comparative examples. [Example 1] The adhesive composition (1) was applied to a release liner (film vinyl 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) using an applicator so that the thickness after drying was 50 μm, and adhesive layers for the first and second adhesive layers were prepared by drying at 80°C for 3 minutes. Next, toluene was added to the base material (1) and stirred until uniform. The mixture was then applied to a release liner using an applicator so that the thickness after drying was 50 μm, and the first base layer was prepared by drying at 60°C for 5 minutes. After peeling off the release liner from the first substrate layer, the adhesive layer from which the release liner had been peeled off was bonded to both sides of the first substrate layer, whose surface was treated with corona to achieve a wetting index of 60 mN / m, thereby forming a first adhesive layer and a second adhesive layer. These layers were then laminated with a roll at a linear pressure of 5 kg / cm and aged at 40°C for 48 hours. Next, the adhesive composition (4) was coated onto the release liner to a thickness of 50 μm after drying, and dried at 80°C for 3 minutes to form adhesive layers for the third and fourth adhesive layers. Next, a foam (1) was prepared as the foam layer, and after corona treatment to achieve a wetting index of 60 mN / m, one adhesive layer each for the third adhesive layer and the fourth adhesive layer were attached to both sides, then laminated with a roll at a linear pressure of 5 kg / cm, and aged at 40°C for 48 hours. Next, the base material (4) was prepared as a second base layer, and the second adhesive layer, which had been matured as described above, was bonded to one side of it. Then, the fourth adhesive layer, which had been matured as described above, was bonded to the other side of the second base layer, and the adhesive tape (1) was manufactured by laminating it with a roll at a linear pressure of 5 kg / cm.

[0400] [Example 2] An adhesive tape (2) was obtained in the same manner as in Example 1, except that the first base material layer used base material (2) instead of base material (1).

[0401] [Example 3] An adhesive tape (3) was obtained in the same manner as in Example 1, except that the base material (3) was used as the first base layer.

[0402] [Example 4] An adhesive tape (4) was obtained in the same manner as in Example 2, except that adhesive composition (2) was used instead of adhesive composition (1) as the adhesive composition for the first and second adhesive layers.

[0403] [Example 5] An adhesive tape (5) was obtained in the same manner as in Example 2, except that adhesive composition (3) was used instead of adhesive composition (1) as the adhesive composition for the first and second adhesive layers.

[0404] [Example 6] An adhesive tape (6) was obtained in the same manner as in Example 2, except that foam (2) was used instead of foam (1) as the foam layer.

[0405] [Example 7] An adhesive tape (7) was obtained in the same manner as in Example 2, except that foam (3) was used instead of foam (1) as the foam layer.

[0406] [Example 8] The adhesive composition (1) was applied to a release liner (film vinyl 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) using an applicator so that the thickness after drying was 50 μm, and adhesive layers for the first and second adhesive layers were prepared by drying at 80°C for 3 minutes. Next, toluene was added to the base material (2) and stirred until uniform. The mixture was then applied to a release liner using an applicator so that the thickness after drying was 50 μm, and the first base layer was prepared by drying at 60°C for 5 minutes. After peeling off the release liner from the first substrate layer, the adhesive layer from which the release liner had been peeled off was bonded to both sides of the first substrate layer, whose surface was treated with corona to achieve a wetting index of 60 mN / m, thereby forming a first adhesive layer and a second adhesive layer. These layers were then laminated with a roll at a linear pressure of 5 kg / cm and aged at 40°C for 48 hours. Next, the adhesive composition (4) was applied to the release liner so that its thickness after drying was 50 μm, and dried at 80°C for 3 minutes to form an adhesive layer for the third adhesive layer. Next, a foam (1) was prepared as the foam layer, and after corona treatment to achieve a wetting index of 60 mN / m, the adhesive layer for the third adhesive layer was bonded to one side, and then laminated with a roll at a linear pressure of 5 kg / cm, and aged at 40°C for 48 hours. Next, the second adhesive layer, which had finished maturing as described above, was attached to the side of the foam layer to which the third adhesive layer had been attached as described above, opposite to the third adhesive layer, and the adhesive tape (8) was manufactured by laminating it with a roll at a linear pressure of 5 kg / cm.

[0407] [Example 9] The adhesive composition (1) was applied to a release liner (film vinyl 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) using an applicator so that the thickness after drying was 50 μm, and an adhesive layer for the first adhesive layer was prepared by drying at 80°C for 3 minutes. Next, toluene was added to the base material (2) and stirred until uniform. The mixture was then applied to a release liner using an applicator so that the thickness after drying was 50 μm, and the first base layer was prepared by drying at 60°C for 5 minutes. After peeling off the release liner from the first substrate layer, the adhesive layer from which the release liner had been peeled off was bonded to one side of the first substrate layer, whose surface had been corona-treated to achieve a wetting index of 60 mN / m, thereby forming the first adhesive layer. This layer was then laminated with a roll at a linear pressure of 5 kg / cm and aged at 40°C for 48 hours. Next, the adhesive composition (4) was applied to the release liner so that its thickness after drying was 50 μm, and dried at 80°C for 3 minutes to form an adhesive layer for the third adhesive layer. Next, a foam (1) was prepared as the foam layer, and after corona treatment to achieve a wetting index of 60 mN / m, the adhesive layer for the third adhesive layer was bonded to one side, and then laminated with a roll at a linear pressure of 5 kg / cm, and aged at 40°C for 48 hours. Next, the side of the first substrate layer with the first adhesive layer prepared above, opposite to the first adhesive layer, was treated with corona to achieve a wetting index of 60 mN / m. This was then bonded to the side of the foam layer with the third adhesive layer prepared above, opposite to the third adhesive layer, and laminated with a roll at a linear pressure of 5 kg / cm to produce an adhesive tape (9).

[0408] [Example 10] The adhesive composition (1) was applied to a release liner (film vinyl 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) using an ...

Claims

1. It comprises, in order, a first adhesive layer, a first substrate layer, a foam layer, and a third adhesive layer. The first substrate layer has a breaking strength of 1.0 to 100.0 MPa and a breaking elongation of 400 to 1500%. The first substrate layer has a rubber hardness of 20 to 90A. An adhesive tape having a 25% compressive strength of 40 to 160 kPa and a tensile strength of 3.0 to 15.0 MPa in the foam layer.

2. The first adhesive layer adjacent to the first substrate layer is formed from an adhesive composition containing filler particles with an average particle size of 10 to 40 μm and an adhesive resin. The adhesive tape according to claim 1, wherein the amount of filler particles in the adhesive layer containing the filler particles is 3 to 50 parts by mass per 100 parts by mass of the adhesive resin.

3. The adhesive tape according to claim 1 or 2, wherein the first substrate layer has a 100% modulus of 1 to 5 MPa.

4. The first substrate material of the first substrate layer contains a styrene-based resin, The adhesive tape according to any one of claims 1 to 3, wherein the styrene resin is a hydrogenated copolymer obtained by hydrogenating a block copolymer composed of at least a polymer block (A) mainly consisting of styrene compound units and a polymer block (B) mainly consisting of isoprene units, butadiene units, or isoprene and butadiene units.

5. The adhesive tape according to any one of claims 1 to 4, further comprising a second adhesive layer between the first base material layer and the foam layer.

6. The second adhesive layer adjacent to the first substrate layer is formed from an adhesive composition containing filler particles with an average particle size of 10 to 40 μm and an adhesive resin. The adhesive tape according to claim 5, wherein the amount of filler particles in the adhesive layer containing the filler particles is 3 to 50 parts by mass per 100 parts by mass of the adhesive resin.

7. The adhesive tape according to claim 5 or 6, further comprising a fourth adhesive layer between the second adhesive layer and the foam layer.

8. The adhesive tape according to claim 7, further comprising a second base material layer between the second adhesive layer and the fourth adhesive layer.

9. A bonding body comprising an adhesive tape according to any one of claims 1 to 8, a first adherend that adheres to the surface of the first adhesive layer of the adhesive tape, and a second adherend that adheres to the surface of the third adhesive layer of the adhesive tape.

10. A method for dismantling a joint according to claim 9, A method for disassembling a joint, comprising the step of stretching at least the first base material layer of the adhesive tape to separate the second adherend from the first adherend.

11. A method for disassembling a joint comprising an adhesive tape according to claim 8, a first adherend that adheres to the surface of the first adhesive layer of the adhesive tape, and a second adherend that adheres to the surface of the third adhesive layer of the adhesive tape, A method for dismantling a joint, comprising the step of separating the second adherend from the first adherend by stretching at least the first base layer of the adhesive tape while leaving the second base layer of the adhesive tape on the surface of the second adherend.

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