Adhesive tape

Abstract

To provide an adhesive tape that can be more easily and more quickly removed from an adherend. [Solution] The adhesive tape comprises a base layer and adhesive layers on both sides of the base layer, the base layer having a thickness of 10 to 100 μm, a breaking strength of 20 to 90 MPa, a breaking elongation of 400 to 1500%, and a 100% modulus of 1 to 5 MPa, and the adhesive composition forming the adhesive layer contains 1 to 40 mass% of filler particles with an average particle size of 0.1 to 40 μm, relative to 100 mass% of the adhesive composition.

Description

[Technical Field]

[0001] This invention relates to adhesive tape. [Background technology]

[0002] Adhesive tape is widely used as a joining method in various industrial fields such as office automation equipment, IT and home appliances, and automobiles for purposes 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 or discarded products in various industrial fields such as home appliances and automobiles. When recycling or 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 as a label. However, in recent years, adhesive tape has been attached to various parts of the product, making the process of peeling off the adhesive tape complicated. Furthermore, in products with many components densely mounted, in order to remove a single component from among the densely packed components, it is necessary to pull the adhesive tape off at a high angle (for example, 60° or more) relative to the surface to which it is attached. However, pulling at such a high angle puts a load on the adhesive tape, and in particular, if one tries to stretch the adhesive tape as quickly as possible, the adhesive tape may tear. Therefore, in the adhesive tape removal process, there is a demand for a reduction in work costs by making the adhesive tape easier and quicker to remove.

[0005] Therefore, the present invention is an invention made in view of the above problems, and an object thereof is to provide an adhesive tape that can be removed more simply and quickly from an adherend.

Means for Solving the Problems

[0006] 〔1〕An adhesive tape comprising a base material layer and adhesive layers on both sides of the base material layer, wherein the base material layer has a thickness of 10 to 100 μm, a breaking strength of 20 to 90 MPa, an elongation at break of 400 to 1500%, and a 100% modulus of 1 to 5 MPa, The adhesive composition for forming the adhesive layer contains 1 to 40% by mass of filler particles having an average particle size of 0.1 to 40 μm with respect to 100% by mass of the adhesive composition, and is characterized in that it is an adhesive tape. 〔2〕The adhesive tape according to the above 〔1〕, wherein the rubber hardness of the base material layer is 60 to 90 A. 〔3〕The adhesive tape according to the above 〔1〕 or 〔2〕, wherein the elongation at break of the base material layer is 400 to 1000%. 〔4〕The adhesive tape according to any one of the above 〔1〕 to 〔3〕, wherein the base material layer contains a styrene-based block copolymer or a hydrogenated product thereof. 〔5〕The base material layer contains a hydrogenated product of a block copolymer composed of at least a hard segment X and a soft segment Y, and the soft segment Y in the hydrogenated product is composed of a random copolymer of a linear structural unit and a structural unit having a side chain. The adhesive tape according to any one of the above 〔1〕 to 〔4〕. 〔6〕The base material layer contains a hydrogenated product of a block copolymer composed of at least a polymer block (A) and a polymer block (B), The polymer block (A) is mainly composed of a structural unit derived from a styrene-based compound, The polymer block (B) is a block composed of a random copolymer of a linear hydrogenated butadiene structural unit (b1) and a hydrogenated isoprene structural unit (b2) having a side chain. The adhesive tape according to any one of the above 〔1〕 to 〔5〕. [7] The adhesive tape according to any one of [1] to [6] above, wherein the base layer mainly contains styrene-ethylene / butadiene-styrene copolymer (SEBS) or styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS). [8] The adhesive tape according to any one of [1] to [7] above, wherein the content of the filler particles is 3.5 to 40% by mass based on 100% by mass of the adhesive composition. [Effects of the Invention]

[0007] The present invention can provide an adhesive tape that can be removed more easily and quickly from the adherend. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram illustrating the method of attaching the adhesive tape 1 to the acrylic plate 2 when evaluating impact resistance in the embodiment. [Figure 2] This is a schematic diagram of the test specimen prepared when evaluating impact resistance in the example. [Figure 3] This is a schematic diagram illustrating the method for setting up test specimens on a U-shaped measuring stand when evaluating impact resistance in the embodiment. [Modes for carrying out the invention]

[0009] 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. "Adhesive tape" The adhesive tape of this embodiment comprises a base layer and adhesive layers on both sides of the base layer. The base layer of the adhesive tape of this embodiment has a thickness of 10 to 100 μm, a breaking strength of 20 to 90 MPa, a breaking elongation of 400 to 1500%, and a 100% modulus of 1 to 5 MPa. Furthermore, the adhesive composition forming the adhesive layer of the adhesive tape of this embodiment contains filler particles with an average particle size of 0.1 to 40 μm at a concentration of 1 to 40% by mass per 100% by mass of the adhesive composition. The adhesive tape of this embodiment, with this configuration, can be removed more easily and quickly from the adherend (the object to which the adhesive tape is applied). Specifically, the base layer of the adhesive tape of this embodiment has a breaking strength of 20 to 90 MPa, a breaking elongation of 400 to 1500%, and a 100% modulus of 1 to 5 MPa. As a result, in the initial stage of peeling the adhesive tape from the adherend (initial stretching of the adhesive tape), the worker can pull it with relatively little force, and throughout the peeling process, the worker can pull the adhesive tape from the adherend at a relatively fast speed without tearing (it can be peeled again). Furthermore, since the base layer of the adhesive tape of this embodiment has a thickness of 10 to 100 μm, the strength of the adhesive tape and the ease of pulling the adhesive tape can be ensured. Furthermore, the adhesive layer of the adhesive tape in this embodiment is formed from an adhesive composition containing 1 to 40% by mass of filler particles with an average particle size of 0.1 to 40 μm. As a result, when the adhesive tape is pulled to peel it off the adherend, the filler particles are exposed from the thinned adhesive layer due to the stretching of the adhesive tape, reducing the adhesive strength of the adhesive layer to the adherend and making it easier to peel off the adhesive tape. Therefore, with the adhesive tape of this embodiment, the adhesive tape can be removed from the object to which it is attached more easily and quickly.

[0010] <Base material layer> In this embodiment, the adhesive tape comprises a base layer between adhesive layers on both sides, the base layer having a thickness of 10 to 100 μm, a breaking strength of 20 to 90 MPa, a breaking elongation of 400 to 1500%, and a 100% modulus of 1 to 5 MPa.

[0011] In this embodiment, the base 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 tape. It is preferable that it contains the following base material, and may also contain other components as needed. The base layer may be a single layer, or it may be a multi-layer structure of two, three, or more layers.

[0012] In this embodiment, the base layer has a breaking strength of 20 to 90 MPa, preferably 30 to 90 MPa, and more preferably 40 to 90 MPa. A breaking strength of 20 MPa or more allows the worker to peel the adhesive tape from the adherend without tearing, even when pulling it at a relatively fast speed. Furthermore, a breaking strength of 90 MPa or less prevents the worker from experiencing excessive stress when pulling the adhesive tape. The breaking strength of the base material layer in adhesive tape is determined by punching out a dumbbell-shaped piece of the base material layer with a gauge length of 20 mm and a width of 5 mm, and then 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 base layer.

[0013] In this embodiment, the base layer has a breaking elongation of 400 to 1500%, preferably 400 to 1200%, and more preferably 400 to 1000%. A breaking elongation of 400% or more prevents excessive stress from being generated 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 when peeling off the adhesive tape, allowing for work in a small space. The elongation at break of the base layer in adhesive tape is measured by punching out a dumbbell-shaped piece of the base layer with a gauge length of 20 mm and a width of 5 mm, and then 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 tensile elongation measured when it breaks. Furthermore, the elongation at break can be adjusted by selecting appropriate materials and by applying stretching during the manufacturing process of the base layer.

[0014] In this embodiment, the base layer has a 100% modulus of 1 to 5 MPa, preferably 1 to 4.5 MPa, and 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 stages of peeling it off. The 100% modulus of the base layer in adhesive tape refers to the stress value measured when the elongation is 100%, after punching out a dumbbell-shaped piece of the base 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 base layer.

[0015] In this embodiment, the base layer preferably has a rubber hardness of 60 to 90A, more preferably 60 to 85A, and even more preferably 65 to 85A. A rubber hardness of 60A or higher effectively prevents the adhesive tape from tearing when it is stretched and peeled off. A rubber hardness of 90A or lower makes the base layer softer, which, for example, allows the adhesive tape to absorb impact more easily when an object to which the tape is attached is dropped, thus protecting the object from impact (improving the impact resistance of the adhesive tape). The rubber hardness of the base layer in adhesive tape 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.

[0016] The base layer has a thickness of 10 to 300 μm, preferably 20 to 250 μm, and more preferably 30 to 200 μm. A thickness of 10 μm or more ensures the strength of the adhesive tape, while a thickness of 300 μm or less avoids the problem of the adhesive tape becoming difficult to pull due to excessive thickness. In this specification, "thickness of the base layer" refers to the average value of the thicknesses measured at any five points in the base layer using the TH-104 paper and film thickness measuring instrument (manufactured by Testa-Sangyo Co., Ltd.).

[0017] There are no particular restrictions on the ratio of the thickness of the adhesive layer to the base 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 base layer, expressed as [thickness of adhesive layer / thickness of base 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 adhesive layer to the thickness of the base 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 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, as the adhesive layer may not be able to follow the shape.

[0018] <<Materials for base material>> The base material is not particularly limited as long as a base layer having the above-mentioned specific physical properties can be obtained, but examples include styrene-based resins such as polystyrene, styrene-isoprene copolymer, styrene-isoprene-styrene copolymer, styrene-isoprene-butadiene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene copolymer, styrene-ethylene-propylene copolymer, styrene-butadiene-isoprene copolymer, styrene-ethylene-ethylene / propylene-styrene block copolymer, and styrene-ethylene / butadiene-styrene copolymer; polyurethane resins such as ester-based polyurethane and ether-based polyurethane; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; polycarbonate; polymethylpentene; polysulfone; polyether-ether-ketone; polyethersulfone; polyetherimide; polyimide film; fluororesin; nylon; and acrylic resin. These may be used individually or in combination of two or more. Among these, styrene-based resins are preferred because they easily provide the specific physical properties mentioned above.

[0019] The styrene-based resin is preferably a styrene-based block copolymer and / or a hydrogenated styrene-based block copolymer, such as styrene-isoprene copolymer, styrene-isoprene-styrene copolymer, styrene-isoprene-butadiene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-butadiene-isoprene copolymer, styrene-ethylene / butadiene-styrene copolymer, or styrene-ethylene-ethylene / propylene-styrene block copolymer. More specifically, it is preferable that the block copolymer is hydrogenated and composed of at least a polymer block (A) mainly consisting of structural units derived from a styrene-based compound (hereinafter abbreviated as styrene-based compound units), and a polymer block (B) mainly consisting of structural units derived from isoprene (hereinafter abbreviated as isoprene units), structural units derived from butadiene (hereinafter abbreviated as butadiene units), or structural units derived from a mixture of isoprene and butadiene (hereinafter abbreviated as isoprene and butadiene units).

[0020] In the following explanation, isoprene units, butadiene units, and isoprene and butadiene units in polymer block (B) constituting the styrene-based block copolymer may be collectively referred to as structural units derived from conjugated dienes or conjugated diene units. Furthermore, hydrogenated block copolymers may be referred to as hydrogenated block copolymers or hydrogenated block copolymers, and in hydrogenated block copolymers, structural units derived from hydrogenated conjugated dienes in polymer block (B) may be referred to as hydrogenated conjugated diene units. In addition, in the above styrene-based block copolymer, polymer block (A) mainly composed of styrene-based compound units is the hard segment, and polymer block (B) mainly composed of conjugated diene units or hydrogenated conjugated diene units is the soft segment.

[0021] The polymer block (A) and polymer block (B) will be described in order below.

[0022] 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 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). Examples of styrene-based compounds that constitute polymer block (A) 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 aromatic vinyl compounds 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.

[0023] 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-vinylcarbasol, 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.

[0024] 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.

[0025] 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.

[0026] 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. Furthermore, all "weight-average molecular weight" as described herein and in the claims is the weight-average molecular weight on a standard polystyrene basis, determined by gel permeation chromatography (GPC) measurement, and more specifically, the value measured according to the method described in the examples. 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 the weight-average molecular weight of the second polymer block A can be determined by subtracting them from the weight-average molecular weight of the styrene resin. Alternatively, in the case of a triblock copolymer having an ABA structure, the total weight-average molecular weight of polymer blocks (A) can be calculated as the weight-average molecular weight of the styrene resin and 1 The 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.

[0027] 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.

[0028] Polymer block (B) mainly consists of isoprene units, butadiene units, or isoprene and butadiene units. "Mainly consists of" here 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 isoprene and / or butadiene 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). Furthermore, polymer block (B) may also include 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, completely alternating, partially block-like, block, or a combination of two or more of these.

[0029] 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.

[0030] 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-vinylcarbasol, 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.

[0031] 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.

[0032] 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 more detailed conditions are as described in the examples.

[0033] As long as polymer blocks (A) and polymer blocks (B) are bonded together, the bonding structure of the styrene resin is not limited and can be linear, branched, radial, or a combination of two or more of these. Among these, the bonding structure of polymer blocks (A) and polymer blocks (B) is preferably linear. Examples of such polymer blocks 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 preferably used. 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.

[0034] 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.

[0035] In this embodiment, the polymer block (B) and / or optionally present polymer block (C) in the styrene resin preferably have crystalline structural units such as ethylene units and propylene units. Furthermore, the polymer block (B) and / or optionally present polymer block (C) preferably also have side chains to suppress excessive crystallinity. Styrene resins having these structural units exhibit excellent tensile strength.

[0036] 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.

[0037] 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.

[0038] 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 molded by 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).

[0039] In this embodiment, the styrene-based resin includes hydrogenated block copolymers such as styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS) and styrene-(ethylene-butylene)-styrene block copolymer (SEBS).

[0040] Furthermore, regardless of whether or not it is a styrene-based resin, in this embodiment, it is preferable that the base layer contains a hydrogenated block copolymer (sometimes referred to as a hydrogenated block copolymer) composed of at least a hard segment X and a soft segment Y, and that the soft segment Y in the hydrogenated copolymer is composed of a random copolymer of linear structural units and structural units having side chains. In particular, it is preferable that the base layer mainly contains a hydrogenated block copolymer comprising the hard segment X described above and a soft segment Y composed of a random copolymer of linear structural units and structural units having side chains. The random presence of linear structural units that contribute to crystallinity and structural units that contribute to extensibility within the soft segment Y constituting the hydrogenated block copolymer makes it easier to achieve both improved extensibility and fracture strength. That is, the steric hindrance of the structural units having side chains in the soft segment Y allows it to exhibit extensibility without impairing it, while the presence of linear structural units in the soft segment Y increases the cohesive force and thus the fracture strength by forming a crystalline structure between molecules when stretched.

[0041] In particular, when articles in which a pair of adherends are joined via adhesive tape are used in applications where they are heated and exposed to high temperatures, the base layer may become brittle due to thermal melting, making it difficult to peel off by stretching. In contrast, by using a base layer mainly composed of a hydrogenated block copolymer containing the soft segment Y composed of the random copolymer described above, even if the intermolecular entanglement in the hard segment X is resolved by heat, the intermolecular entanglement in the linear structural units of the soft segment Y is maintained, making the base layer less susceptible to heating and melting, thus suppressing brittleness. As a result, the adhesive tape can be removed from adherends more easily and quickly, not only from objects in their normal state but also from objects after heating.

[0042] Furthermore, the main component in the above-mentioned base material layer refers to the component that is present in more than 50% by mass of the base material (polymer component) constituting the base material layer.

[0043] The block copolymer that is a precursor of the above-mentioned hydrogenated block copolymer is preferably a triblock copolymer or higher, as this facilitates the expression of the effects of hard segment X and soft segment Y in the hydrogenated block copolymer. A triblock copolymer is preferred. As the block copolymer that is a precursor of the above-mentioned hydrogenated block copolymer having a soft segment, for example, styrene-based block copolymers, urethane-based block copolymers, acrylic-based block copolymers, etc., can be used. The hard segment and soft segment in the styrene-based block copolymer before hydrogenation are the same as those of polymer blocks (A) and (B) described above. The hard segment and soft segment in the urethane-based block copolymer and acrylic-based block copolymer before hydrogenation can be the same as those in general urethane-based block copolymers and acrylic-based block copolymers.

[0044] In the above-described hydrogenated block copolymer, the soft segment Y is composed of a random copolymer of linear structural units and structural units having side chains, formed by adding hydrogen to the soft segment in the precursor block copolymer. The soft segment Y in the above-described hydrogenated block copolymer may also contain structural units other than linear structural units and structural units having side chains. In the above-described hydrogenated block copolymer, the hydrogenation rate of the soft segment Y is preferably 50 mol% or more, more preferably 75 mol% or more, and even more preferably 95 mol% or more.

[0045] The above-mentioned hydrogenated block copolymer can exhibit the above-mentioned functions as long as it has a hard segment X and a soft segment Y composed of a random copolymer of linear structural units and structural units having side chains. Therefore, the type is not particularly limited, and for example, hydrogenated styrene-based block copolymers having the hard segment X and the soft segment Y, hydrogenated urethane-based block copolymers having the hard segment X and the soft segment Y, hydrogenated acrylic-based block copolymers having the hard segment X and the soft segment Y, etc. can be used.

[0046] In particular, hydrogenated styrene-based block copolymers comprising at least a polymer block (A) which is a hard segment X, and a polymer block (B) which is a soft segment Y composed of a random copolymer of linear structural units and structural units having side chains are preferred. In other words, hydrogenated block copolymers comprising at least a polymer block (A) mainly composed of styrene-based compound units and a polymer block (B) mainly composed of conjugated diene units are preferred, and it is more preferable that the polymer block (B) in the hydrogenated block copolymer is composed of a random copolymer of linear hydrogenated butadiene structural units (b1) and hydrogenated isoprene structural units (b2) having side chains.

[0047] In other words, it is preferable that the base layer contains a hydrogenated block copolymer comprising at least polymer block (A) and polymer block (B), wherein polymer block (A) mainly consists of structural units derived from styrene compounds, and polymer block (B) is a block composed of a random copolymer of linear hydrogenated butadiene structural units (b1) and hydrogenated isoprene structural units (b2) having side chains. This is because a hydrogenated styrene-based block copolymer having the above structure easily forms a base layer with specific physical properties, and because it has a polymer block (B) as a soft segment Y composed of a random copolymer of linear hydrogenated butadiene structural units (b1) and hydrogenated isoprene structural units (b2) having side chains, it is easier to exert the effects of the hydrogenated block copolymer described above. Details of polymer block (A), which is the hard segment X, and polymer block (B), which is the soft segment Y, in the hydrogenated styrene-based block copolymer are as previously described.

[0048] As hydrogenated polymers for block copolymers composed of a polymer block (A) mainly consisting of styrene-based compound units, and a polymer block (B) which is composed of a random copolymer of linear hydrogenated butadiene structural units (b1) and hydrogenated isoprene structural units (b2) having side chains, specific examples include styrene-ethylene / butylene-styrene block copolymers (SEBS) and styrene-ethylene-ethylene / propylene-styrene block copolymers (SEEPS). Styrene-ethylene-ethylene / propylene-styrene block copolymers are hydrogenated block copolymers formed from styrene-butadiene-isoprene-styrene. Commercially available SEEPS can be used, for example, Septon 4044, Septon 4055, Septon 4077, and Septon 4099 from Kuraray Co., Ltd. Styrene-ethylene-butylene-styrene block copolymers are hydrogenated block copolymers from styrene-isoprene / butadiene-styrene. Commercially available styrene-isoprene / butadiene-styrene block copolymers can be used, for example, Septon 8004, 8006, and 8007 from Kuraray Co., Ltd.

[0049] In particular, the base layer preferably contains styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS) or styrene-(ethylene-butylene)-styrene block copolymer (SEBS) as its main component, and more preferably contains styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS) as its main component. SEEPS has smaller side chains than SEBS in the polymer block (B), so intermolecular entanglement interactions are more easily exhibited. For this reason, a base layer mainly composed of SEEPS can more effectively suppress the reduction in fracture strength due to thermal embrittlement.

[0050] The various resins mentioned above, which can be used as base materials, can be manufactured by known methods. For example, styrene resins can be manufactured 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.

[0051] 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. 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.

[0052] 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.

[0053] 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; glycoethers 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.

[0054] 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: Ranen-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.

[0055] The styrene-based resin obtained in this way 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.

[0056] -Other ingredients- Other components in the 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 resins; polymer components other than the substrate material; additives such as 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, silica beads, organic beads, 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 base layer can be appropriately selected within a range that does not impair the properties of the adhesive tape.

[0057] Tackifying resins can be used to improve the adhesion between the adhesive layer of adhesive tape and the base material layer, as well as to enhance heat resistance.

[0058] 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.

[0059] 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.

[0060] There are no particular restrictions on the anti-aging agent, and any known agent can be appropriately selected according to the purpose. Examples include phenol-based 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, phenol-based 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 base 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 set the amount used appropriately, taking into consideration the balance between initial adhesion, heat durability, and discoloration prevention.

[0061] Generally, phenol compounds with sterically hindered groups can be used as phenol-based antioxidants, with monophenol, bisphenol, and polyphenol types being typical. 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 types.

[0062] There are no particular restrictions on the amount of phenol-based 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 per 100 parts by mass of the base material, and using it in the range of 0.5 to 3 parts by mass effectively improves the heat stability of the base material. As a result, an adhesive tape can be obtained that maintains good initial adhesion and has even better heat durability.

[0063] <Adhesive layer> In this embodiment, the adhesive tape has an adhesive layer on both sides of the base layer for exhibiting adhesive strength. The adhesive layer in the present invention is formed from an adhesive composition and contains filler particles with an average particle size of 0.1 to 40 μm in an amount of 1 to 40% by mass per 100% by mass of the adhesive composition. The adhesive composition in the present invention preferably contains filler particles and an adhesive resin. In addition, the adhesive composition may optionally contain other components besides filler particles and an adhesive resin.

[0064] 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 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 of the adhesive tape, even though it is fixing two rigid adherends 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%.

[0065] The breaking strength of the adhesive layer is not particularly limited and 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 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 an adhesive tape is thick and has a high breaking strength, it may not be possible to stretch it sufficiently 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, and then broken.

[0066] 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.

[0067] 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 40 μm to 110 μm, and particularly preferably 50 μm to 100 μm. "Thickness of the adhesive layer" refers to the thickness of the adhesive layer on one side of the adhesive tape. When the adhesive tape has adhesive layers on both sides, the average thickness of the adhesive layer on one side and the average thickness of the adhesive layer on the other side may be the same or different, but it is preferable that they be the same thickness. In this specification, the thickness of the adhesive layer can be measured by the following method. Specifically, the adhesive tape is immersed in liquid nitrogen for 1 minute, and then, using tweezers, the adhesive tape is folded in the liquid nitrogen along the width direction to create a section for observing the cross-section in the thickness direction of the adhesive tape. After the section is returned to room temperature in a desiccator, it is fixed to a sample stage so that an electron beam is incident perpendicularly on the cross-section, and the cross-section is observed using an electron microscope. Based on the scale of the electron microscope, the thickness of the adhesive layer on the adhesive tape is measured at 10 locations, and the arithmetic mean is taken as the thickness of the adhesive layer. The thickness of the adhesive layer is the length measured from one surface to the other surface along the lamination direction.

[0068] The adhesive layer in this embodiment is formed from an adhesive composition containing at least filler particles within a predetermined range, with an average particle size within a predetermined range, and an adhesive resin. The components contained in the adhesive composition constituting the adhesive layer will be described below.

[0069] - Filler particles - In this embodiment, the adhesive composition, which is a precursor to the adhesive layer, contains filler particles with an average particle size of 0.1 to 40 μm. Because the adhesive composition, which is a precursor to the adhesive layer, contains these filler particles, when the adhesive tape is stretched, the filler particles are exposed from the adhesive layer, thereby reducing the adhesion area between the adhesive layer and the adherend. Therefore, even when the stretching direction of the adhesive tape is at a relatively large angle with respect to the adhesive surface of the adherend (hereinafter sometimes referred to as the "adhesion surface"), for example, perpendicular (sometimes referred to as the "90° direction"), and even when stretched at a high speed, the adhesive tape can be peeled off more easily and quickly.

[0070] 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.

[0071] 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 carbonate, 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.

[0072] 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.

[0073] Among the organic filler particles, as the silicone-based filler, specifically, silicone rubber particles obtained by three-dimensionally crosslinking linear organopolysiloxane (see Japanese Patent Laid-Open Nos. 63-77942, 3-93834, and 04-198324), powdered silicone rubber (see U.S. Patent No. 3843601, Japanese Patent Laid-Open Nos. 62-270660 and 59-96,122), etc. can be used. Furthermore, silicone composite particles having a structure coated with a silicone resin, which is a polyorganosilsesquioxane cured product having a three-dimensionally crosslinked structure represented by (R’SiO 3 / 2 ) n (where R’ represents a substituted or unsubstituted monovalent hydrocarbon group) (see Japanese Patent Laid-Open No. 7-196815) can also be used. As such silicone particles, Treflil E-500, Treflil E-600, Treflil E-601, Treflil E-850, etc. are commercially available from Toray Dow Corning Silicone Co., Ltd. under the above trade names, and KMP-600, KMP-601, KMP-602, KMP-605, etc. are commercially available from Shin-Etsu Chemical Co., Ltd. and can be used.

[0074] In addition, as another silicone-based filler, acrylic-modified silicone particles can be used. Examples of the acrylic-modified silicone particles include an emulsion graft polymer of a polyorganosiloxane represented by the following general formula (1), an acrylate monomer and / or a methacrylate monomer, and a functional group-containing monomer copolymerizable therewith.

[0075]

Chemical Formula

[0076] (In the above general formula (1), 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 , X3 , X 4 , X 5 , and X 6 Each of these independently represents a substituted or unsubstituted C1-C20 alkyl group, a C6-C20 allyl group, a C1-C20 alkoxy group, or a hydroxyl group, Y 1 and Y 2 Each is independent of X 1 or -[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 allyl 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.

[0077] In general formula (1), R 1 or R 2The 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 this formula include phenyl groups, tolyl groups, and naphthyl groups. R 1 or R 2 Preferably, it is a methyl group.

[0078] In general formula (1), X 1 ~X 9 The alkyl groups with 1 to 20 carbon atoms and the alkyl groups with 6 to 20 carbon atoms represented by R are: 1 or R 2 Examples of groups similar to the alkyl and allyl groups exemplified above include the groups shown. 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.

[0079] In general formula (1), 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 film will have poor flexibility, 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 (1) 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.

[0080] Examples of acrylic acid ester monomers or methacrylic acid ester monomers include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and cyclohexyl methacrylate.

[0081] Examples of functional group-containing monomers copolymerizable with 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.

[0082] The acrylic-modified silicone powder is preferably obtained by mixing 100 parts by mass of polyorganosiloxane represented by the general formula (1) 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.

[0083] Acrylic-modified silicone particles are granulated and powdered by the following methods: spray drying, airflow drying, etc., but a spray dryer is preferred in terms of productivity. Powdering is preferably done by hot drying, and processing at 80 to 150°C is preferable.

[0084] As acrylic-modified silicone particles, commercially available products such as Charine R-170S and Charine R-200 (both manufactured by Nisshin Chemical Industry Co., Ltd.) can also be used.

[0085] There are no particular restrictions on the shape of the filler particles; they can be appropriately selected according to the purpose, and may be regular or irregular in shape. Specific examples of filler particle shapes include polygonal, cubic, elliptical, spherical, needle-shaped, plate-shaped, and flaky shapes. These filler particles may be used individually or in combination of two or more types. Furthermore, these filler particles may be aggregated. Among these, elliptical, spherical, and polygonal shapes are preferred for the filler particles. When the filler particles are 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.

[0086] There are no particular restrictions on the particle size distribution (D90 / D10) of the filler particles, and it can be appropriately selected depending on 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 is within the 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 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 is less than 2.5, the tensile 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 can be obtained, for example, by measuring the average particle size of the filler particles using a laser diffraction scattering method (microtrac) and converting it into a particle size distribution.

[0087] The average particle size of the filler particles is 0.1 to 40 μm, preferably 5 to 40 μm, more preferably 10 to 35 μm, even more preferably 10 to 30 μm, and particularly 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 adhesive tape's base material is thin, and it exhibits excellent impact resistance, shear adhesion, and splitting adhesion. On the other hand, if the particle size of the filler particles is less than 0.1 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 measuring instrument (Microtrac) that employs laser diffraction scattering.

[0088] When using silicone rubber particles or silicone composite particles as filler particles, the average particle size of the silicone rubber particles or silicone composite particles is preferably 0.1 to 40 μm, and more preferably 5 to 40 μm. If the average particle size is less than 0.1 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 particles as filler particles, the average particle size of the acrylic-modified silicone particles is preferably 0.1 to 40 μm, more preferably 5 to 40 μm, even more preferably 5 to 30 μm, and even more preferably 10 to 25 μm. If the average particle size is less than 0.1 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.

[0089] 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, and it can be appropriately selected depending on the purpose. However, it is preferable that the ratio of the average particle size of the filler particles to the average thickness of the adhesive layer, expressed as [volume 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 adhesive tape's base material is thin. Furthermore, when the ratio is 95 / 100 or less, it is advantageous in that the adhesive performance, such as impact resistance, shear adhesion strength, and splitting adhesion strength, is also superior.

[0090] The content of filler particles in the adhesive layer is 1 to 40% by mass per 100% by mass of the adhesive composition, but is preferably 3.5 to 40% by mass, preferably 5 to 37% by mass, and more preferably 15 to 35% by mass. A filler particle content of 1% by mass or more per 100% by mass of the adhesive composition allows for easier and quicker removal of the adhesive tape. Furthermore, a filler particle content of 40% by mass or less per 100% by mass of the adhesive composition 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.

[0091] Furthermore, when using the above-mentioned silicone rubber particles or silicone composite particles as filler particles, the content of the silicone rubber particles or silicone composite particles is preferably 15 to 35% by mass per 100% by mass of the adhesive composition. Furthermore, when using the above-mentioned acrylic-modified silicone particles as filler particles, the content of the acrylic-modified silicone particles is preferably 1.0 to 20% by mass per 100% by mass of the adhesive composition.

[0092] 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.

[0093] -Adhesive resin- There are no particular restrictions on the adhesive resin, and it can be appropriately selected from known materials. Examples include acrylic adhesive resins, rubber adhesive resins, urethane adhesive resins, and silicone adhesive resins. These may be used individually or in combination of two or more. Among these, acrylic adhesive resins are preferred.

[0094] --Acrylic adhesive resin-- There are no particular restrictions on the acrylic adhesive resin, and it can be appropriately selected depending on the purpose. For example, it may contain an acrylic polymer and, if necessary, additives such as a tackifying resin or a crosslinking agent.

[0095] Acrylic polymers can be produced, for example, by polymerizing (meth)acrylate monomers. As the (meth)acrylate monomer, for example, alkyl (meth)acrylates 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.

[0096] 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.

[0097] Alkyl (meth)acrylates having an alkyl group with 1 to 12 carbon atoms are preferably used in an amount of 80 to 98.5% by mass, and more preferably in an amount of 90 to 98.5% by mass, relative to the total amount of monomers used in the production of the acrylic polymer.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] Specific examples of vinyl monomers having an amide group include (meth)acrylic monomers such as N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, and N,N-dimethylacrylamide.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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).

[0108] 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 million (manufactured by Tosoh Corporation)

[0109] As for the acrylic adhesive resin, it is preferable to use one that contains a tackifying resin in order to improve adhesion to the substrate and surface bonding strength.

[0110] 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. However, a softening point of 30°C to 180°C is preferred, and a softening point of 70°C to 140°C is more preferred for forming an adhesive layer with high adhesive performance. When using a (meth)acrylate-based tackifying resin, its glass transition temperature is preferably 30°C to 200°C, and more preferably 50°C to 160°C.

[0111] 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.

[0112] There are no particular restrictions on the amount of tackifying resin used, and it can be appropriately selected according to the purpose. However, it is preferable to use 5 to 65 parts by mass per 100 parts by mass of acrylic polymer, and more preferably 8 to 55 parts by mass, as this makes it easier to ensure adhesion to the adherend.

[0113] 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.

[0114] 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 it is more preferable to use isocyanate-based crosslinking agents and epoxy-based crosslinking agents, which have high reactivity with acrylic polymers.

[0115] 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.

[0116] As an indicator of the degree of crosslinking, the gel fraction value, which is measured by the amount of insoluble matter 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, 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.

[0117] The gel fraction refers to the value measured by the following method. The adhesive composition is applied to a release sheet so that the thickness after drying is 50 μm, dried at 100°C for 3 minutes, and aged at 40°C for 2 days. A 50 mm square is then cut out and used as the sample. Next, the mass of the sample before immersion in toluene (G1) is measured in advance. 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, and the mass of the residue after drying at 110°C for 1 hour (G2) is measured. The gel fraction is then determined according to the following formula (4). The mass of filler 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...Equation (4)

[0118] --Rubber-based adhesive resin-- There are no particular restrictions on the rubber-based adhesive resin, and examples include rubber materials that can be commonly used as adhesive resins, such as synthetic rubber-based adhesive resins and natural rubber-based adhesive resins, as well as those containing additives such as tackifying resins as needed.

[0119] Examples of rubber materials include block copolymers of aromatic vinyl compounds and conjugated diene compounds, specifically 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. These may be used individually or in combination of two or more. Among these, using two or more styrene-based resins in combination is more preferable because it can provide the adhesive tape with excellent adhesive properties and holding power, and using a combination of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer is particularly preferable.

[0120] Styrene resins may be single-structured, such as linear, branched, or multi-branched structures, or they may be mixed and used in combination with other structures. When a styrene resin rich in linear structures is used in the adhesive layer, it can provide excellent adhesive performance to the adhesive tape. On the other hand, styrene resins with branched or multi-branched structures but with styrene blocks at the molecular ends can adopt a pseudo-crosslinked structure, providing excellent cohesive force and thus high holding power. For this reason, it is preferable to mix and use styrene resins according to the required properties.

[0121] As for the styrene-based resin, it is preferable to use one that contains the structural unit represented by the following chemical formula (2) in an amount of 10% to 80% by mass, more preferably in an amount of 12% to 60% by mass, even more preferably in an amount of 15% to 40% by mass, and particularly preferably in an amount of 17% to 35% by mass, relative to the total mass of the styrene-based resin. This allows for excellent adhesion and heat resistance to be obtained. Note that in the following chemical formula (2), * represents a bond with another atom.

[0122] [ka]

[0123] When using a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer in combination as the styrene-based resin, the content of the styrene-isoprene copolymer relative to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is preferably 0% to 80% by mass, more preferably 0% to 77% by mass, even 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, the adhesive tape can achieve both excellent adhesive performance and heat durability.

[0124] 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 an adhesive tape with good workability in the manufacturing process while also possessing heat resistance, which is therefore preferable.

[0125] Here, the weight-average molecular weight of the styrene-isoprene copolymer 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: 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 million (manufactured by Tosoh Corporation)

[0126] There are no particular restrictions on the method for producing styrene-based resins; a conventionally known method can be appropriately selected. A block copolymer can be obtained by an anionic living polymerization method, and a coupling agent can be added as needed to carry out the reaction, thereby obtaining the styrene-based resin. Specifically, there are no particular restrictions on the method for producing the styrene-isoprene copolymer, and a 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] There are no particular restrictions on the tackifying resin contained in the rubber-based adhesive resin, and it can be appropriately selected according to the purpose, but it is preferable to use a tackifying resin with a softening point of 80°C or higher. This makes it possible to obtain an adhesive tape with excellent initial adhesion and heat resistance.

[0131] The tackifying resin is preferably one that is solid at room temperature (23°C). Specific examples include petroleum resins such as C5-type petroleum resins, C9-type petroleum resins, C5-type / C9-type petroleum resins, and alicyclic petroleum resins, as well as polymerized rosin resins, terpene resins, rosin resins, terpene-phenol resins, styrene resins, coumarone-indene resins, xylene resins, and phenol resins. These may be used individually or in combination of two or more. Among these, using a combination of C5-type petroleum resin and polymerized rosin resin is preferable for achieving both superior initial adhesion and heat resistance.

[0132] Petroleum resin is easily compatible with the structural unit represented by the chemical formula (1) that constitutes styrene-based resin, and as a result, the initial adhesive strength and heat durability of the adhesive tape can be further improved.

[0133] Examples of C5-type petroleum resins include Escorets 1202, Escorets 1304, Escorets 1401 (all manufactured by ExxonMobil), Wingtack 95 (manufactured by Goodyear Tyre & Rubber Company), Quinton K100, Quinton R100, Quinton F100 (all manufactured by Zeon Corporation), Picotack 95, and Picopel 100 (manufactured by Rika Hercules Co., Ltd.).

[0134] Examples of C9-based petroleum resins include Nippon Oil Neopolymer L-90, Nippon Oil Neopolymer 120, Nippon Oil Neopolymer 130, Nippon Oil Neopolymer 140, Nippon Oil Neopolymer 150, Nippon Oil Neopolymer 170S, Nippon Oil Neopolymer 160, Nippon Oil Neopolymer E-100, Nippon Oil Neopolymer E-130, Nippon Oil Neopolymer 130S, and Nippon Oil Neopolymer S (all manufactured by JX Nippon Oil & Energy Corporation), and Petcool (registered trademark) (manufactured by Tosoh Corporation).

[0135] As C5 / C9 petroleum resins, copolymers of C5 petroleum resin and C9 petroleum resin can be used. For example, Escorets 2101 (manufactured by ExxonMobil), Quinton G115 (manufactured by Zeon Corporation), and Harcotac 1149 (manufactured by Rika Hercules Corporation) can be used.

[0136] Alicyclic petroleum resins can be obtained by hydrogenating C9 petroleum resins, and examples include Escorets 5300 (manufactured by ExxonMobil), Alcon P-100 (manufactured by Arakawa Chemical Industries, Ltd.), and Rigalite R101 (manufactured by Rika Hercules Co., Ltd.).

[0137] There are no particular restrictions on the amount of tackifying resin used, and it can be appropriately selected according to the purpose. However, it is preferable to use it 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 of components constituting the rubber-based adhesive resin. By using the tackifying resin within the above preferred range, it becomes easier to achieve both excellent break elongation and heat durability of the adhesive tape while improving interfacial adhesion between the adhesive layer and the substrate layer.

[0138] There are no particular restrictions on the amount of tackifying resin with a softening point of 80°C or higher used, and it can be appropriately selected according to the purpose. However, it is preferable to use it in the range of 3% to 100% by mass relative to the total amount of styrene resin, more preferably in the range of 5% to 80% by mass, and particularly preferable to use it in the range of 5% to 80% by mass to obtain an adhesive tape that achieves both even better adhesion and excellent heat resistance.

[0139] Furthermore, in order to obtain adhesive properties and initial adhesion in a constant temperature environment, a tackifying resin with a softening point of -5°C or lower can be used in combination with a tackifying resin with a softening point of 80°C or higher.

[0140] There are no particular restrictions on the tackifying resin having a softening point of -5°C or lower; it can be appropriately selected from known tackifying resins depending on the purpose, but it is preferable to use a tackifying resin that is liquid at room temperature.

[0141] Specific examples of tackifying resins with a softening point of -5°C or lower include process oils, polyesters, and liquid rubbers such as polybutene. These may be used individually or in combination of two or more. Among these, using polybutene as the tackifying resin with a softening point of -5°C or lower is preferable for achieving even better initial adhesion.

[0142] Tackifying resins with a softening point of -5°C or lower are preferably used in an amount of 0% to 40% by mass relative to the total amount of tackifying resin, and more preferably in an amount of 0% to 30% by mass.

[0143] Furthermore, as a tackifying resin with a softening point of -5°C or lower, it is preferable to use it in an amount of 0% to 40% by mass relative to the total amount of styrene-based resin, and more preferably in an amount of 0% to 30% by mass, as this improves initial adhesion, allows for good adhesion, and provides sufficient heat resistance.

[0144] There are no particular restrictions on the mass ratio of the tackifying resin with a softening point of 80°C or higher to the tackifying resin with a softening point of -5°C or lower, and it can be appropriately selected according to the purpose. However, it is preferable to use a mass ratio of the tackifying resin with a softening point of 80°C or higher to the tackifying resin with a softening point of -5°C or lower, expressed as [mass of tackifying resin with a softening point of 80°C or higher / mass of tackifying resin with a softening point of -5°C or lower], in the range of 5 to 50, and more preferably in the range of 10 to 30, in order to obtain an adhesive tape that achieves both excellent initial adhesion and excellent holding power.

[0145] There are no particular restrictions on the mass ratio of styrene resin to tackifying resin, and it can be appropriately selected according to the purpose. However, it is preferable to use a mass ratio of styrene resin to tackifying resin, expressed as [styrene resin / tackifying resin], in the range of 0.5 to 10.0, and more preferably in the range of 0.6 to 9.0, as this can improve initial adhesion and provide excellent heat resistance. Furthermore, a mass ratio [styrene resin / tackifying resin] greater than 1 is preferable in order to prevent peeling due to the repulsive force of the adhesive tape when applied to curved surfaces of the adherend (repulsion resistance).

[0146] --Urethane-based adhesive resin-- A urethane-based adhesive resin refers to an adhesive resin that contains a urethane polymer as a base polymer. Typically, the above-mentioned urethane-based adhesive resin consists of a urethane polymer obtained by reacting a polyol with a polyisocyanate compound as a base polymer, and may contain additives such as tackifying resins as needed. The urethane polymer is not particularly limited, and an appropriate one can be selected from various urethane polymers that can function as an adhesive (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. As tackifying resins that can be contained in the urethane-based adhesive resin, the tackifying resins exemplified above for acrylic-based adhesive resins and styrene-based adhesive resins can be used.

[0147] -Other ingredients- The adhesive composition constituting the adhesive layer in this embodiment may optionally further contain other components in addition to filler particles and adhesive resin, as needed. There are no particular limitations on the other components in the adhesive layer; they 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, anti-aging agents, UV absorbers, fillers, polymerization inhibitors, surface modifiers, antistatic agents, defoaming agents, 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 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.

[0148] The adhesive composition forming the adhesive layer may, in addition to the adhesive resin described above, optionally contain a crosslinking agent. This is because the cohesive force of the adhesive layer can be increased by including a crosslinking agent. The type of crosslinking agent is not particularly limited and can be appropriately selected from conventionally 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 can be used alone or in combination of two or more types. Among these, the use of isocyanate-based crosslinking agents and epoxy-based crosslinking agents is preferred from the viewpoint of improving cohesive force. Specific isocyanate-based crosslinking agents are as described above. The amount of crosslinking agent used is not particularly limited and can be selected from a range of approximately 0.005 to 10 parts by mass, preferably approximately 0.01 to 5 parts by mass, per 100 parts by mass of adhesive resin, for example.

[0149] The adhesive composition for forming the adhesive layer may be foamable or in a foamed state. For this purpose, the adhesive composition may contain a foaming agent during formulation. Very preferably, the foaming agent is an expanded or expandable form of microballoon. However, chemical foaming agents may be used alone or in combination with other foaming agents. The adhesive composition may be foamable or foamed physically, i.e., by the formulation of gaseous or supercritical liquid substances or mixtures of substances.

[0150] In particular, it is preferable that the foaming described above be carried out by incorporating microballoons and then inflating them.

[0151] A "microballoon" is understood to be a micro-hollow bead having an inflatable thermoplastic polymer shell. These beads are filled with a low-boiling point liquid or liquefied gas. Polyacrylonitrile, PVDC, PVC, or polyacrylate are particularly used as shell materials. Suitable low-boiling point liquids include lower alkane hydrocarbons, such as isobutane or isopentane, which are encapsulated as liquefied gases within the polymer shell under pressure.

[0152] In particular, the outer polymer shell softens due to the action of heat on the microballoon. Simultaneously, the liquid foaming agent gas present in the shell 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 polymer shell is maintained, a closed-cell foam is obtained.

[0153] A variety of microballoons are commercially available and are distinguished by their size (diameter of 6-45 μm in the unexpanded state) and the initiation temperature required for expansion (75-220°C). One example of a commercially available microballoon is the ExpanseL® DU type (DU = dry, unexpanded) from Akzo Nobel.

[0154] Unexpanded microballoons are available as solids or aqueous dispersions with a microballoon content of approximately 40-45% by mass. Furthermore, polymer-bound microballoons (masterbatches), such as polymer-bound microballoons with a microballoon concentration of approximately 65% ​​by mass in ethyl vinyl acetate, are also available. Both microballoon dispersions and masterbatches are suitable as manufacturing methods for foaming adhesive compositions.

[0155] Foamed adhesive compositions can also be produced using so-called pre-expanded microballoons. In this category, expansion occurs before the microballoons are mixed into the polymer matrix. Pre-expanded microballoons are commercially available, for example, under the name Dualite® or Akzo Nobel's designation Expansion xxx DE (dry expanded product).

[0156] When the adhesive composition contains microballoons, at least 90% of the total hollow space formed by the microballoons in the adhesive layer preferably has a maximum diameter of 20 to 75 μm, more preferably 25 to 65 μm. "Maximum diameter" is understood to mean the maximum elongation of the microballoon in any spatial direction.

[0157] The diameter can be determined by observing the edges of the adhesive tape, which has been frozen and then fractured, under 500x magnification using a scanning electron microscope (REM). The diameter of each individual microballoon can then be visually determined.

[0158] When using microballoons for foaming, the microballoons can be supplied to the formulation in batches, as a paste, or as uncut or cut powder. Furthermore, the microballoons may exist suspended in a solvent.

[0159] The proportion of microballoons in the adhesive composition is preferably 0.5% to 2.5% by mass, and more preferably 1.0% to 2.0% by mass, based on the entire adhesive composition. The above values ​​represent the values ​​of unexpanded microballoons.

[0160] The adhesive composition may contain expandable microhollow beads in addition to the filler particles described above, and regardless of the inclusion of expandable microhollow beads, it may also contain non-expandable microhollow beads different from the filler particles described above. The microhollow beads only need to have almost all gas-containing cavities permanently sealed by a dense film, and it is not relevant whether the shell film consists solely of an elastic and thermoplastic stretchable polymer mixture or, for example, an elastic and non-thermoplastic glass within the temperature range permissible in plastic processing.

[0161] Other beads that can be included in the adhesive composition include, for example, polymer solid beads, glass hollow beads, glass solid beads, ceramic hollow beads, ceramic solid beads and / or carbon solid beads ("carbon microballoons").

[0162] The relative density of the adhesive composition (adhesive layer) when foamed is preferably 450 to 950 kg / m³. 3 Preferably 600-800 kg / m 3 That is the case.

[0163] Relative density refers to the ratio of the density of a foamed adhesive composition to the density of an unfoamed adhesive composition of the same formulation. The relative density of the adhesive composition is preferably 0.20 to 0.99, more preferably 0.30 to 0.90, and particularly 0.50 to 0.85.

[0164] (Adhesive composition) The adhesive layer can be formed using an adhesive such as a water-based adhesive containing the above-mentioned adhesive composition, a solvent-type adhesive, a hot-melt adhesive, or an active energy ray-curing adhesive. A water-based adhesive refers to an adhesive in which the adhesive composition (adhesive layer forming component) is contained in a solvent mainly composed of water (water-based solvent), and typically includes what is called a water-dispersible adhesive (a form in which at least a part of the adhesive composition is dispersed in water). A solvent-type adhesive refers to a form in which the adhesive composition is contained in an organic solvent. In the adhesive tape of this embodiment, it is preferable to form the adhesive layer using a solvent-type adhesive from the viewpoint of suitably realizing adhesive properties such as shear adhesion strength.

[0165] <Other layers> In the adhesive tape of this embodiment, there are no particular limitations, and other layers may be provided as appropriate depending on the purpose. Examples include a primer layer, an antistatic layer, a non-combustible layer, a decorative layer, a conductive layer, a thermal conductive layer, and a release layer.

[0166] <Shape, characteristics, etc. of adhesive tape> The adhesive tape of this embodiment is not particularly limited in shape and dimensions, as long as it comprises a base layer and adhesive layers on both sides of the base layer. For example, it includes adhesive tape having a shape and dimensions suitable for attaching to a predetermined object (e.g., adhesive tape after die-cutting) and sheet-like long adhesive tape (e.g., adhesive tape before being processed into a specific shape). Furthermore, the adhesive tape of this embodiment can optionally have a non-adhesive gripping area for, for example, attachment to or removal from an object.

[0167] 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 base layer, but it is preferably 15 μm to 800 μm, more preferably 30 μm to 540 μm, even more preferably 60 μm to 320 μm, and particularly preferably 70 μm to 250 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.).

[0168] The hardness (Type A hardness (Shore A hardness)) of the adhesive tape is not particularly limited and can be appropriately selected depending on the purpose, but 10 to 90 is preferred, 20 to 85 is more preferred, and 64 to 85 is even more preferred. If the Shore A hardness of the adhesive tape is within the above preferred range, the re-peeling work by pulling off the adhesive tape becomes easier. On the other hand, if the Shore A hardness is less than 10, the adhesive tape may tear when stretched and peeled off, and if it exceeds 90, the stress required to stretch and re-peel the adhesive tape may become too high, making re-peeling impossible. The rubber hardness of adhesive tape 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.

[0169] The stress of the adhesive tape 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 adhesive tape at 25% elongation is between 0.15 MPa and 82 MPa, suitable adhesive strength can be obtained for the adhesive tape, and it can be peeled off relatively easily even when elongation peeling occurs. On the other hand, if the stress of the adhesive tape at 25% elongation is less than 0.15 MPa, there is a risk that the adhesive tape will peel off when a load is applied in the shear direction to the adhesive tape, even though it is fixing two hard adherends together. 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 25% elongation stress of adhesive tape refers to the stress value measured when the adhesive tape 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 elongated by 25%.

[0170] There are no particular restrictions on the breaking strength of the adhesive tape, and it can be appropriately selected depending on the purpose, but 20 MPa to 100.0 MPa is preferred, 20 MPa to 90.0 MPa is more preferred, 30 MPa to 85.0 MPa is even more preferred, and 40 MPa to 85.0 MPa is particularly preferred. If the breaking strength of the adhesive tape is within the above preferred range, it is possible to suppress the tape from tearing when stretching and peeling it off quickly, and the load required to stretch the tape does not become excessive, making it easier to peel off and re-peel it. On the other hand, if the breaking strength of the adhesive tape is less than 20 MPa, the tape may tear when stretching and peeling it off quickly, and if it exceeds 100.0 MPa, it may not be possible to stretch the tape sufficiently and re-peel it off when attempting to stretch and re-peel it. Furthermore, the force required to stretch and deform the adhesive tape also depends on the thickness of the tape. For example, even if you try to stretch and re-peel an adhesive tape that is thick and has high breaking strength, you may not be able to stretch it sufficiently and therefore be unable to re-peel it. The breaking strength of adhesive tape is determined by punching out a dumbbell-shaped piece of adhesive tape with a gauge length of 20 mm and a width of 5 mm, and then using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of 23°C and 50% RH, pulling it lengthwise at a tensile speed of 500 mm / min. The stress value measured at the time of fracture refers to the stress value measured when the tape breaks.

[0171] There are no particular restrictions on the elongation at break of the adhesive tape, and it can be appropriately selected depending on the purpose, but 400% to 1500% is preferred, 400% to 1300% is more preferred, and 400% to 1000% is even more preferred. When the elongation at break of the adhesive tape is 400% or more, even if the adhesive tape is firmly adhered to the substrate, the stress required to stretch the tape horizontally to vertically relative to the surface of the substrate when re-peeling off the tape will not be too great, and the tape will not stretch excessively when peeling it off, allowing it to be easily removed. Furthermore, when the elongation at break is 1500% or less, the stretching distance horizontally to vertically relative to the surface of the substrate when re-peeling off the adhesive tape will not be too long, allowing work to be done in a small space. On the other hand, if the elongation at break is less than 400%, when re-peeling the adhesive tape, it may not be possible to peel it off with breakage when stretching it horizontally to vertically from the surface to which it is attached. If it exceeds 1500%, when re-peeling the adhesive tape, the stretching distance horizontally to vertically from the surface to which it is attached becomes too long, which can make the work difficult. The break elongation of adhesive tape refers to the tensile elongation measured when the tape breaks after being punched into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled lengthwise at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH.

[0172] The adhesive tape of this embodiment can be peeled off even when pulled perpendicular to the surface to which it is applied (90° direction) under predetermined conditions. Specifically, the adhesive tape of this embodiment, when evaluated according to the "90° stretch peeling (high speed) evaluation" described in the Examples section below, either "the adhesive tape broke 0 times out of 3" or "the adhesive tape broke 1 time out of 3, and / or the area of ​​adhesive composition remaining on the adherend was less than 1 / 5 of the initial application area." Having such physical properties makes it possible to remove the adhesive tape from the adherend even more easily and quickly.

[0173] 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.

[0174] 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 20N / 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 stretching it horizontally to vertically from the surface to which it is attached to the adherend. The 180° peel adhesive strength of the adhesive tape refers to the value measured in accordance with JIS Z 0237.

[0175] <Method for manufacturing adhesive tape> In this embodiment, there are no particular limitations on the method for manufacturing the adhesive tape, and a known method can be appropriately selected. The method for manufacturing the adhesive tape in this embodiment preferably includes an adhesive layer formation step, a base 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 base layer formation step are performed simultaneously.

[0176] The adhesive layer formation process is not particularly limited as long as an adhesive layer can be formed, and can be appropriately selected according to the purpose. Examples include methods for forming an adhesive layer on the surface of a release sheet by heat pressing, casting by extrusion molding, uniaxial stretching, sequential secondary stretching, simultaneous biaxial stretching, inflation, tube method, calendar method, and solution method. Among these, casting by extrusion molding and the solution method 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 that has been sealed with cray or polyvinyl alcohol, and then one or both sides of that paper have been treated with a release agent such as a silicone resin. These may be used individually or in combination of two or more types.

[0177] The substrate layer formation process is not particularly limited as long as it can form a substrate 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 tube 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 tube method, the calendering method, and the solution method are preferred for imparting suitable flexibility and extensibility to the substrate layer. Furthermore, the base 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.

[0178] The lamination process involves laminating a substrate layer and an adhesive layer. There are no particular restrictions on the method of laminating the substrate layer and the adhesive layer; any known method can be appropriately selected. For example, one method involves laminating the substrate layer with the adhesive layer, which is attached to a release sheet formed in the adhesive layer formation process, under pressure.

[0179] <Uses of adhesive tape> Adhesive tape can be suitably used in various industrial fields for fixing and temporarily securing parts, such as fixing sheet metal parts together or 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 use as labels to display product information.

[0180] 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]

[0181] 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.

[0182] The adhesive tapes obtained in each example and comparative example were measured and evaluated according to the following method.

[0183] (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 Tables 1 and 2 below.

[0184] (2) Measurement of the 100% modulus of the substrate layer Each base layer was punched out in a dumbbell shape with a gauge length of 20 mm and a width of 5 mm. Under measurement conditions of 23°C and 50% RH, a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) was used to measure the stress value when the base layer was stretched to 100% by pulling it in the longitudinal direction at a tensile speed of 500 mm / min. The results are shown in Tables 1 and 2 below.

[0185] (3) Measurement of rubber hardness A durometer (spring-type rubber hardness tester) (model: GS-719G, manufactured by Teclock Co., Ltd.) was used to measure the Type A hardness (Shore A) of each adhesive tape in accordance with JIS K 6253. The results are shown in Tables 1 and 2 below.

[0186] (4) Measurement of the thickness of the substrate layer The thickness of five arbitrary points within the substrate layer was measured using a TH-104 paper / film thickness measuring instrument (manufactured by Testa-Sangyo Co., Ltd.). The average of these measurements was used as the thickness of the substrate layer. The results are shown in Tables 1 and 2 below.

[0187] (5) Measurement of the thickness of the adhesive layer After immersing the adhesive tape in liquid nitrogen for 1 minute, the tape was folded and split along its width using tweezers in the liquid nitrogen to create a section for observing the cross-section in the thickness direction. After returning the section to room temperature in a desiccator, it was fixed to a sample stage so that the electron beam was incident perpendicularly on the cross-section, and the cross-section was observed using an electron microscope (Miniscope® TM3030Plus, manufactured by Hitachi High-Technologies Corporation). Based on the electron microscope scale, the thickness of the adhesive layer in the adhesive tape was measured at 10 locations, and the arithmetic mean was taken as the thickness of the adhesive layer. The thickness of the adhesive layer is the length measured from one surface to the other surface along the lamination direction. The results are shown in Tables 1 and 2 below.

[0188] (6) Measurement of the average particle size of filler particles The average particle size of filler particles was measured using a laser diffraction scattering device (Microtrac). The results are shown in Tables 1 and 2 below.

[0189] (7) Evaluation of 90° stretch peeling (high speed) Each piece of adhesive tape was cut to a length of 60 mm and a width of 10 mm. Of these, 10 mm in length and 10 mm in width was left to protrude as a gripping hand, and one side of the adhesive tape was attached to a clean, smooth aluminum plate (length 150 mm, width 50 mm, thickness 2 mm, alloy number A1050) under conditions of 23°C and 50% RH. Next, a clean, smooth acrylic plate (length 150 mm, width 50 mm, thickness 2 mm, 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 laminated structure of the aluminum plate, adhesive tape, and acrylic plate was then compressed by applying a load of 5 kg with a roller for one back-and-forth motion, and then left to stand for 3 days under conditions of 23°C and 50% RH to obtain the test specimen. Under ambient conditions of 23°C and 50% RH, the gripping portion of the adhesive tape on the test specimen was stretched at a tensile speed of 1000 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) with the load limiter set to -15N, at a 90° (perpendicular) angle to the acrylic plate side relative to the adhesive surface of the adhesive tape. During this process, the occurrence of breakage in the adhesive tape and the degree of residue of the adhesive composition on the adherend (at least one of the aluminum plate and the acrylic plate) after the adhesive tape was removed were visually confirmed. The above method was used for three tests, and the re-peelability (peeling in the vertical direction) was evaluated based on the following evaluation criteria. The results are shown in Tables 1 and 2 below. [Evaluation Criteria] ◎: The adhesive tape did not break in 0 out of 3 attempts. ○: The adhesive tape broke once out of three attempts, and / or the area of ​​adhesive composition remaining on the adherend was less than 1 / 5 of the initial application area. △: The adhesive tape broke in 1 out of 3 attempts, and the adhesive tape did not stretch, with the area of ​​adhesive tape remaining on the adherend being 4 / 5 or more of the initial application area. ×: The adhesive tape broke in 2 or more out of 3 attempts, and / or the adhesive tape did not stretch and could not be re-peeled. ◎ and ○ indicate items that are perfectly usable.

[0190] (8) Evaluation of 90° stretch peeling (low speed) In the "Evaluation of Vertical Extension Peeling (High Speed)" described above, the tensile speed of the adhesive tape was changed from 1000 mm / min to 500 mm / min, and the same test was conducted and evaluated. The results are shown in Tables 1 and 2 below.

[0191] (9) Evaluation of impact resistance Two pieces of each adhesive tape were prepared, each cut to a length of 20 mm and a width of 5 mm. As shown in Figure 1, the adhesive tapes 1 were attached parallel to an acrylic plate (50 mm long, 50 mm wide, 2 mm thick, Acrylite L, color: clear, manufactured by Mitsubishi Rayon Co., Ltd.) 2, with a 40 mm gap between them. Next, as shown in Figure 2, the acrylic plate 2 with the adhesive tapes 1 attached was attached to the center of an ABS plate (150 mm long, 100 mm wide, 2 mm thick, Tough Ace R, manufactured by Sumitomo Bakelite Co., Ltd., color: natural, no texture) 3. A load of 2 kg was applied to the laminated structure of the acrylic plate 2, the adhesive tapes 1, and the ABS plate 3, and the plates were pressed together by pressing with a roller for one back-and-forth motion. After that, the plate was left to stand for 24 hours under conditions of 40°C and 50% RH to obtain the test specimen. As shown in Figure 3, a U-shaped measuring stand (150 mm long, 100 mm wide, 45 mm high, and 5 mm thick, made of aluminum) 4 was placed on the base of a DuPont impact tester (manufactured by Tester Industries Co., Ltd.), and the test specimen was placed on it so that the acrylic plate 2 of the test specimen was facing downwards (Figure 3). Under conditions of an atmosphere of 23°C and 50% RH, a stainless steel impacting pin (25 mm in diameter, 300 g in mass) 5 was dropped from the ABS plate 3 side to the center of the ABS plate 3. At this time, the height of the impacting pin 5 was changed by 10 cm starting from 10 cm, and the impacting pin 5 was dropped 5 times at 10-second intervals for each height, and the height at which peeling or breakage of the adhesive tape on the test specimen was observed was measured, and the impact resistance was evaluated based on the evaluation criteria below. The results are shown in Tables 1 and 2 below. [Evaluation Criteria] ◎: When the Gekishin 5 was dropped from a height of 60 cm or more, the adhesive tape did not peel off or break. ○: When the strike core 5 was dropped from a height of 30cm to 50cm, the adhesive tape did not peel off or break. △: When the striking core 5 was dropped from a height of 10 cm to less than 30 cm, the adhesive tape peeled off or broke. ×: When the height of the striking core 5 reached 10 cm, the adhesive tape peeled off or broke. ◎ and ○ indicate items that are not problematic in terms of use.

[0192] (10) Evaluation of 180° peel adhesion strength The 180° peel adhesion strength was measured in accordance with JIS Z 0237. Specifically, each adhesive tape was cut to a length of 150 mm and a width of 20 mm, and one side of the adhesive tape was backed with a PET film with a thickness of 25 μm. Next, the other side of the adhesive tape was attached to a stainless steel plate (length 100 mm, width 30 mm, thickness 3 mm) under an atmosphere of 23°C and 50% RH. A load of 2 kg was applied to the laminated structure of the adhesive tape and the stainless steel plate, and the material was pressed together by pressing it back and forth once with a roller. After that, the material was left to stand for 1 hour under an atmosphere of 23°C and 50% RH to prepare the test specimen. The adhesive tape on the aforementioned test specimen was peeled in a 180° direction at a tensile speed of 300 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of an atmosphere of 23°C and 50% RH, and the 180° peel adhesion strength of the adhesive tape was measured. The results are shown in Tables 1 and 2 below.

[0193] (11) Evaluation of stretch peeling (after heating) Each piece of adhesive tape was cut to a length of 60 mm and a width of 10 mm. Of these, 10 mm in length and 10 mm in width was left to protrude as a gripping hand, and one side of the adhesive tape was attached to a clean, smooth stainless steel plate 1 (length 150 mm, width 30 mm, thickness 2 mm) under conditions of 23°C and 50% RH. Next, a clean, smooth stainless steel plate 2 (length 150 mm, width 30 mm, thickness 2 mm) was attached to the side of the adhesive tape opposite to the side to which stainless steel plate 1 was attached. A load of 5 kg was applied to the laminated structure of stainless steel plate 1, the adhesive tape, and stainless steel plate 2, and the layers were pressed together by pressing with a roller for one back-and-forth motion. After that, the structure was left to stand for 10 minutes under conditions of 200°C, and this was used as the test specimen. After allowing the specimens to cool sufficiently to room temperature under conditions of 23°C and 50% RH, the gripping portion of the adhesive tape on the test specimen was grasped by hand and stretched horizontally relative to the adhesive surface of the tape. At this time, it was confirmed whether stainless steel plates 1 and 2 could be separated. The results are shown in Tables 1 and 2 below. [Evaluation Criteria] ○: Stainless steel plate 1 and stainless steel plate 2 were successfully removed. ×: The adhesive tape broke, making it impossible to separate stainless steel plate 1 and stainless steel plate 2.

[0194] Next, the materials used in the examples and comparative examples are as follows.

[0195] <Material for base material> ·Base material (1) (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 then vacuum-dried to obtain the base material (1). The obtained base material (1) was a styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS) with 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%. Furthermore, a toluene solution of the base material (1) was obtained by dissolving the above base material (1) in toluene and adjusting the solid content to 20%.

[0196] ·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, 300 mL of isoprene and 300 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 a 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 then vacuum-dried to obtain the base material (2). The obtained base material (2) was a styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS) with a styrene content of 30% by mass, a weight-average molecular weight of 98,000, a molecular weight distribution of 1.02, and a hydrogenation rate of 98%. Furthermore, a toluene solution of base material (2) was obtained by dissolving base material (2) in toluene and adjusting the solid content to 20%.

[0197] ·Base material (3) (SEEPS+MAM) To 100 parts by mass of the solid content of base material (1), 15 parts by mass of an acrylic block copolymer (methyl methacrylate-acrylate-methyl methacrylate block copolymer (MAM), Clarity LA2330 manufactured by Kuraray Co., Ltd.) was taken and diluted and mixed while dissolving in toluene to obtain a toluene solution of base material (3), which is a mixture of SEEPS and MAM.

[0198] ·Base material (4) (SIS) As the base material (4), styrene-isoprene-styrene block copolymer (SIS) resin (Quintac 3620, manufactured by Nippon Zeon Co., Ltd.) was used. Furthermore, the base material (4) was diluted with toluene to obtain a toluene solution of the base material (4).

[0199] • Base material (5) (urethane) As the base material (5), a film of an ester-based polyurethane compound (Mobilon Film MF100T, manufactured by Nisshinbo Textile Co., Ltd.) was used.

[0200] ·Base material (6) (PET) As the base material (6), a polyethylene terephthalate (PET) film (Lumira-S10, manufactured by Toray Industries, Inc.) was used.

[0201] ·Base material (7) (SEBS) As the base material (7), styrene-ethylene-butadiene-styrene copolymer (SEBS) resin (Septone 8004, manufactured by Kuraray Co., Ltd.) was used. The base material (7) had a styrene content of 31% by mass. Furthermore, a toluene solution of the base material (7) was obtained by adjusting the solid content of the base material (7) to 20% using toluene.

[0202] <Adhesive composition> The filler particles contained in the adhesive composition of the present invention were as follows:

[0203] <<Filler particles>> • Filler particles (1) (silicone-based filler) As filler particles (1), silicone composite powder (KMP-601, manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 12 μm) was used.

[0204] • Filler particles (2) (aluminum hydroxide) As filler particles (2), aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., BW153, average particle size 18 μm) was used.

[0205] • Filler particles (3) (silicone-based filler) As filler particles (3), silicone composite powder (KMP-602 manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 30 μm) was used.

[0206] • Filler particles (4) (silicone-based filler) As filler particles (4), silicone composite powder (KMP-600, manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 5 μm) was used.

[0207] <<Preparation of Adhesive Composition>> • Adhesive composition (1) 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), which 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) with a solid content of 35% by mass. Next, 30 parts by mass of filler particles (1) were added to 100 parts by mass of the solid content of the obtained adhesive resin solution (1). 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.

[0208] • Adhesive composition (2) To 100 parts by mass of the solid content of the adhesive resin solution (1), 50 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, nonvolatile 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 (2) with a solid content of 40% by mass.

[0209] • Adhesive composition (3) To 100 parts by mass of the solid content of the adhesive resin solution (1), 30 parts by mass of filler particles 3 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 (3) 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.

[0210] · Adhesive composition (4) To 100 parts by mass of the solid content of the adhesive resin solution (1), 30 parts by mass of filler particles 4 were added. Subsequently, a crosslinking agent (Varock 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 (4) at 1.3 parts by mass based on 100 parts by mass of the adhesive resin solution (1), and after stirring and mixing uniformly, ethyl acetate was added to obtain an adhesive composition (4) with a solid content of 40% by mass.

[0211] · Adhesive composition (5) To 100 parts by mass of the solid content of the adhesive resin solution (1), 50 parts by mass of filler particles 1 were added. Subsequently, a crosslinking agent (Varock 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 (1) at 1.3 parts by mass based on 100 parts by mass of the adhesive resin solution (1), and after stirring and mixing uniformly, ethyl acetate was added to obtain an adhesive composition (5) with a solid content of 40% by mass.

[0212] · Adhesive composition (6) To 100 parts by mass of the solid content of the adhesive resin solution (1), 75 parts by mass of filler particles 1 were added. Subsequently, a crosslinking agent (Varock 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 (1) at 1.3 parts by mass based on 100 parts by mass of the adhesive resin solution (1), and after stirring and mixing uniformly, ethyl acetate was added to obtain an adhesive composition (6) with a solid content of 40% by mass.

[0213] Subsequently, examples and comparative examples will be described.

[0214] [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 an adhesive layer was prepared by drying at 80°C for 3 minutes. Next, a toluene solution of the base material (1) was applied to the release liner using an applicator so that the thickness after drying was 50 μm, and the base layer was prepared by drying at 60°C for 5 minutes. After peeling off the release liner from the base material layer, the adhesive layer from which the release liner had been peeled off was bonded to both sides of the base material layer, and the laminated structure of the base material layer and the adhesive layer was laminated by applying pressure of 0.2 MPa to produce an adhesive tape (1). The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0215] [Example 2] In the production of adhesive tape (1) in Example 1, adhesive tape (2) was manufactured in the same manner as in Example 1, except that adhesive composition (1) was changed to adhesive composition (2). The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0216] [Example 3] In the production of the adhesive tape (1) of Example 1, the adhesive tape (3) was produced in the same manner as in Example 1, except that the toluene solution of the base material (1) was replaced with the toluene solution of the base material (2) to create the base layer. The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0217] [Example 4] In the production of the adhesive tape (1) of Example 1, the adhesive tape (4) was produced in the same manner as in Example 1, except that the toluene solution of the base material (1) was replaced with the toluene solution of the base material (3) to create the base layer. The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0218] [Example 5] In the production of the adhesive tape (1) of Example 1, adhesive tape (5) was manufactured in the same manner as in Example 1, except that adhesive composition (1) was changed to adhesive composition (3). The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0219] [Example 6] In the production of the adhesive tape (1) of Example 1, adhesive tape (6) was manufactured in the same manner as in Example 1, except that adhesive composition (1) was changed to adhesive composition (4). The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0220] [Example 7] In the production of the adhesive tape (1) of Example 1, adhesive tape (7) was produced in the same manner as in Example 1, except that adhesive composition (1) was changed to adhesive composition (5). The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0221] [Example 8] In the production of the adhesive tape (1) of Example 1, the adhesive tape (8) was produced in the same manner as in Example 1, except that the toluene solution of the base material (1) was replaced with the toluene solution of the base material (7) to create the base layer. The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 1.

[0222] [Comparative Example 1] In the production of the adhesive tape (1) of Example 1, the adhesive tape (9) was produced in the same manner as in Example 1, except that the toluene solution of the base material (1) was replaced with the toluene solution of the base material (4) to create the base layer. The obtained adhesive tapes were evaluated using the method described above, and the results are shown in Table 2.

[0223] [Comparative Example 2] In the production of the adhesive tape (1) of Example 1, an adhesive tape (10) was produced in the same manner as in Example 1, except that the base material layer was changed to the base material (5). The obtained adhesive tape was evaluated by the above method, and the results are shown in Table 2.

[0224] [Comparative Example 3] In the production of the adhesive tape (1) of Example 1, an adhesive tape (11) was produced in the same manner as in Example 1, except that the thickness of the base material layer was changed to 300 μm. The obtained adhesive tape was evaluated by the above method, and the results are shown in Table 2.

[0225] [Comparative Example 4] In the production of the adhesive tape (1) of Example 1, an adhesive tape (12) was produced in the same manner as in Example 1, except that the base material layer was changed to the base material (6). The obtained adhesive tape was evaluated by the above method, and the results are shown in Table 2.

[0226] [Comparative Example 5] In the production of the adhesive tape (1) of Example 1, an adhesive tape (13) was produced in the same manner as in Example 1, except that the adhesive composition (1) was changed to the adhesive composition (6). The obtained adhesive tape was evaluated by the above method, and the results are shown in Table 2.

[0227] [Table 1]

[0228] [Table 2]

[0229] As shown in Tables 1 and 2, the examples with a thickness of 10 to 100 μm, a breaking strength of 20 to 90 MPa, a breaking elongation of 400 to 1500%, and a 100% modulus within the range of 1 to 5 MPa exhibited superior 90° stretch peel (high speed) and adhesive strength compared to the comparative examples with values ​​outside these ranges. Therefore, it was found that the adhesive tapes of the examples could be removed from the adherend more easily and quickly. Furthermore, adhesive tapes using SEEPS, SEEPS+MAM, and SEBS as base materials were shown to exhibit superior stretch peel after heating. [Industrial applicability]

[0230] According to the present invention, it is possible to provide an adhesive tape that can be removed from an adherend more easily and quickly. [Explanation of symbols]

[0231] 1: Adhesive tape 2: Acrylic sheet 3:ABS board 4: U-shaped measuring stand 5: Strike core

Claims

1. An adhesive tape comprising a base layer and an adhesive layer, The aforementioned substrate layer has a thickness of 10 to 100 μm, a breaking strength of 20 to 90 MPa, a breaking elongation of 400 to 1500%, and a 100% modulus of 1 to 5 MPa. The substrate layer includes a block copolymer composed of at least polymer block (A) and polymer block (B), The polymer block (A) mainly consists of structural units derived from styrene compounds, The polymer block (B) is a block composed of a random copolymer of linear hydrogenated butadiene structural units (b1) and hydrogenated isoprene structural units (b2) having side chains. The adhesive composition that forms the adhesive layer comprises at least an adhesive resin and filler particles, The adhesive resin is selected from the group consisting of acrylic adhesive resins, rubber adhesive resins, and urethane adhesive resins. The filler particles are organic filler particles with an average particle size of 0.1 to 40 μm. An adhesive tape containing 1 to 40% by mass of the filler particles per 100% by mass of the adhesive composition, and having a 180° peel adhesive strength of 15 N / 20 mm to 50 N / 20 mm.

2. The adhesive tape according to claim 1, wherein the rubber hardness of the base layer is 60 to 90A.

3. The adhesive tape according to claim 1 or 2, wherein the elongation at break of the base layer is 400 to 1000%.

4. The adhesive tape according to any one of claims 1 to 3, wherein the base layer comprises a styrene-based block copolymer or a hydrogenated thereof.

5. The adhesive tape according to any one of claims 1 to 4, wherein the substrate layer is composed of at least a hard segment X and a soft segment Y, and the soft segment Y includes a block copolymer composed of a random copolymer of linear structural units and structural units having side chains.

6. The adhesive tape according to any one of claims 1 to 5, wherein the base layer comprises styrene-ethylene / butadiene-styrene copolymer (SEBS) or styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS).

7. An adhesive tape according to any one of claims 1 to 6, which can be stretched and peeled off.

8. An electronic device in which components are fixed using the adhesive tape described in any one of claims 1 to 7.

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